WO2022065095A1 - Piston temperature estimation device, piston temperature control device, piston temperature estimation method, and piston temperature control method - Google Patents

Piston temperature estimation device, piston temperature control device, piston temperature estimation method, and piston temperature control method Download PDF

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Publication number
WO2022065095A1
WO2022065095A1 PCT/JP2021/033479 JP2021033479W WO2022065095A1 WO 2022065095 A1 WO2022065095 A1 WO 2022065095A1 JP 2021033479 W JP2021033479 W JP 2021033479W WO 2022065095 A1 WO2022065095 A1 WO 2022065095A1
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Prior art keywords
temperature
piston
estimation
unit
mouth
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PCT/JP2021/033479
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French (fr)
Japanese (ja)
Inventor
拓朗 三田
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いすゞ自動車株式会社
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Publication of WO2022065095A1 publication Critical patent/WO2022065095A1/en

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    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M1/00—Pressure lubrication
    • F01M1/08—Lubricating systems characterised by the provision therein of lubricant jetting means
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01M—LUBRICATING OF MACHINES OR ENGINES IN GENERAL; LUBRICATING INTERNAL COMBUSTION ENGINES; CRANKCASE VENTILATING
    • F01M5/00—Heating, cooling, or controlling temperature of lubricant; Lubrication means facilitating engine starting
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P3/00—Liquid cooling
    • F01P3/06—Arrangements for cooling pistons
    • F01P3/10—Cooling by flow of coolant through pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F01—MACHINES OR ENGINES IN GENERAL; ENGINE PLANTS IN GENERAL; STEAM ENGINES
    • F01P—COOLING OF MACHINES OR ENGINES IN GENERAL; COOLING OF INTERNAL-COMBUSTION ENGINES
    • F01P7/00—Controlling of coolant flow
    • F01P7/14—Controlling of coolant flow the coolant being liquid
    • F01P7/16—Controlling of coolant flow the coolant being liquid by thermostatic control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D45/00—Electrical control not provided for in groups F02D41/00 - F02D43/00

Definitions

  • the present disclosure relates to a piston temperature estimation device, a piston temperature control device, a piston temperature estimation method, and a piston temperature control method.
  • Patent Documents 1 and 2 Conventionally, a method of estimating the temperature of the piston of an internal combustion engine and controlling the temperature of the piston according to the estimated temperature is known (see, for example, Patent Documents 1 and 2).
  • the top surface temperature of the piston is estimated based on the fuel injection amount and the engine rotation speed.
  • the oil jet is controlled based on the estimated top surface temperature of the piston.
  • the temperature of the piston is calculated based on the second cooling loss generated from the combustion chamber to the piston and the temperature of the combustion gas.
  • the oil jet is controlled based on the calculated piston temperature.
  • the temperature of the mouth of the cavity is the highest, and the temperature of other parts other than the mouth is different from the temperature of the mouth.
  • the temperature estimation point is the top surface of the piston, and in the method described in Patent Document 2, it is not clear which part of the piston the temperature estimation point is. Therefore, in the methods described in Patent Documents 1 and 2, the temperature of a predetermined portion other than the mouth portion of the piston is estimated and the predetermined portion is not controlled to an appropriate temperature, and the piston is not used. There is a risk that the life of the piston cannot be extended.
  • An object of the present disclosure is to provide a piston temperature estimation device, a piston temperature control device, a piston temperature estimation method, and a piston temperature control method that can appropriately estimate the piston temperature so as to extend the life of the piston.
  • the piston temperature estimation device is based on a mouth temperature estimation unit that estimates the temperature of the mouth portion of the cavity of the piston constituting the internal combustion engine and the temperature of the mouth portion estimated by the mouth temperature estimation unit.
  • the piston includes a temperature estimation unit for estimating the temperature of other parts other than the mouth portion.
  • the piston temperature control device includes the above-mentioned piston temperature estimation device and a temperature control unit that controls the temperature of the other part based on the temperature of the other part obtained by the processing of the piston temperature estimation device. , Equipped with.
  • the piston temperature estimation method is based on a step of estimating the temperature of the mouth portion of the cavity of the piston constituting the internal combustion engine and the estimated temperature of the mouth portion, other than the mouth portion of the piston. Perform the steps of estimating the temperature of the other part.
  • the piston temperature control method controls the temperature of the other part based on the step of executing the above-mentioned piston temperature estimation method and the temperature of the other part obtained by executing the piston temperature estimation method. Step and perform.
  • a piston temperature estimation device a piston temperature control device, a piston temperature estimation method, and a piston temperature control method that can appropriately estimate the piston temperature so as to extend the life of the piston.
  • Sectional drawing which shows the schematic structure of the engine which concerns on 1st Embodiment and 2nd Embodiment of this disclosure.
  • the block diagram which shows the structure of the piston temperature control apparatus which concerns on 1st Embodiment and 2nd Embodiment of this disclosure. Relationship between the temperature of the mouth portion and the temperature of the other portion in the state where the cooling oil is injected and the state where the cooling oil is not injected according to the first embodiment and the second embodiment of the present disclosure.
  • FIG. 1 is a cross-sectional view showing a schematic configuration of an engine.
  • the engine 10 shown in FIG. 1 is a diesel engine mounted on an automobile such as a truck.
  • the engine 10 includes a cylinder 20 and a piston 40.
  • the internal combustion engine of the present disclosure is not limited to a diesel engine, and may be a gasoline engine or the like.
  • the cylinder 20 is provided with a cooling passage 21.
  • the cooling water of the cylinder 20 is supplied to the cooling passage 21.
  • a liner 22 is provided on the inner peripheral surface of the cylinder 20.
  • the liner 22 may not be provided.
  • An injector 24 is provided on the cylinder head 23 above the cylinder 20 so as to face the center of the top surface of the piston 40.
  • the cylinder head 23 is provided with an intake port 25 and an exhaust port 26 so as to be located on the left and right sides of the injector 24.
  • the intake port 25 and the exhaust port 26 are provided with an intake valve 27 and an exhaust valve 28, respectively.
  • the piston 40 is installed so as to be able to reciprocate in the cylinder 20 along the liner 22.
  • the piston 40 is made of, for example, an aluminum alloy.
  • a cavity 42 is provided on the top surface of the piston upper portion 41 of the piston 40.
  • the piston upper portion 41 has a cooling channel 44 formed along the circumferential direction, an introduction hole 45 for introducing oil into the cooling channel 44, and a discharge hole 46 for discharging oil from the cooling channel 44. It is provided. Oil is introduced into the cooling channel 44 from the oil jet 61 through the introduction hole 45. The introduced oil circulates in the cooling channel 44 and is discharged from the discharge hole 46, so that the piston 40 is efficiently cooled.
  • the oil injected from the oil jet 61 may be referred to as "cooling oil”.
  • a ring groove 47 formed along the circumferential direction is provided on the outer periphery of the piston upper portion 41 of the piston 40.
  • a piston ring 48 that is in sliding contact with the liner 22 is mounted on the ring groove 47.
  • the skirt portion 49 of the piston 40 is provided with a pair of pin boss portions 50 facing each other (only one pin boss portion 50 is shown in FIG. 1).
  • the pair of pin boss portions 50 are each provided with pin fitting holes 51 penetrating from the center side of the piston 40 toward the outer peripheral side of the piston.
  • the upper end of the connecting rod 53 is connected to the pin fitting hole 51 via the piston pin 52.
  • the lower end of the connecting rod 53 is connected to the crankshaft 55 via the crankpin 54.
  • the crankshaft 55 converts the reciprocating motion of the piston 40 into a rotary motion.
  • the oil jet 61 includes a supply valve 62 and a nozzle 63.
  • the supply valve 62 When the supply valve 62 is “closed”, the cooling oil is not injected from the nozzle 63.
  • the supply valve 62 When the supply valve 62 is “open”, cooling oil is injected from the nozzle 63. Since the configuration of the oil jet 61 is known, detailed description thereof will be omitted.
  • An oil passage 65 is provided between the oil jet 61 and an oil pan (not shown).
  • the oil passage 65 is provided with a variable oil pump 64 capable of changing the flow rate of oil.
  • the portion of the oil passage 65 on the oil jet 61 side of the variable oil pump 64 is connected to a supply passage (not shown) that supplies oil to a portion of the engine 10 that requires lubrication.
  • the variable oil pump 64 supplies the oil (lubricating oil) stored in the oil pan to a portion requiring lubrication, an oil jet 61, or the like.
  • FIG. 2 is a block diagram showing the configuration of the piston temperature control device.
  • FIG. 3 is a graph showing the relationship between the temperature of the mouth portion and the temperature of the other portion in the state where the cooling oil is injected and the state where the cooling oil is not injected.
  • the piston temperature control device 100 includes a piston temperature estimation device 110, a storage unit 120, and a temperature control unit 130.
  • the piston temperature estimation device 110 and the temperature control unit 130 have, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like as hardware.
  • a CPU Central Processing Unit
  • ROM Read Only Memory
  • RAM Random Access Memory
  • the piston temperature estimation device 110 includes an acquisition unit 111, a mouth temperature estimation unit 112, a determination unit 113, and another unit temperature estimation unit 114.
  • the acquisition unit 111 acquires engine status information representing the engine status from various sensors.
  • the mouth temperature estimation unit 112 estimates the temperature of the mouth portion 43 of the cavity 42 of the piston 40.
  • the temperature of the mouth portion 43 estimated by the mouth temperature estimation unit 112 may be referred to as “estimated mouth portion temperature”.
  • the determination unit 113 determines whether or not the oil jet 61 injects cooling oil toward the piston 40.
  • the other unit temperature estimation unit 114 is a unit other than the mouth unit 43 in the piston 40 based on the temperature estimation information stored in the storage unit 120 and the estimated mouth unit temperature estimated by the mouth temperature estimation unit 112. Estimate the temperature of.
  • the temperature of the other part estimated by the other part temperature estimation unit 114 may be referred to as “estimated other part temperature”.
  • the other unit temperature estimation unit 114 estimates the temperature of the pin boss unit 50, which is an example of the other unit.
  • the other portion temperature estimation unit 114 estimates the temperature of the upper edge portion of the pin fitting hole 51 in the pin boss portion 50.
  • the other unit temperature estimation unit 114 selects a predetermined time constant from a plurality of time constants stored in the storage unit 120, and corrects the estimated other unit temperature using the selected time constant.
  • the temperature of the other part corrected by using the time constant may be referred to as “corrected other part temperature”.
  • the storage unit 120 stores the mouth temperature estimation map.
  • the mouth temperature estimation map is a map showing the relationship between the rotation speed of the crankshaft 55, the fuel injection amount, and the estimated temperature of the mouth portion 43.
  • the mouth temperature estimation map is used for estimating the estimated mouth temperature in the mouth temperature estimation unit 112.
  • the storage unit 120 stores the first estimation formula represented by the following formula (1) and the second estimation formula represented by the formula (2).
  • the first estimation formula is an example of the first estimation information
  • the second estimation formula is an example of the second estimation information.
  • the temperature estimation information is composed of the first estimation formula and the second estimation formula.
  • the first estimation formula and the second estimation formula are used for estimating the estimated temperature of the other part in the other part temperature estimation unit 114.
  • the first estimation formula and the second estimation formula are not limited to the formulas (1) and (2). Further, the first estimation information and the second estimation information may be in a map format such as a mouth temperature estimation map.
  • T ON ⁇ ON ⁇ TK + ⁇ ON ⁇ ⁇ ⁇ (1)
  • T OFF ⁇ OFF ⁇ TK + ⁇ OFF ⁇ ⁇ ⁇ (2)
  • T OFF Cooling oil is injected Estimated temperature of other parts when not in use ⁇ OFF, ⁇ OFF : Coefficient when cooling oil is not injected
  • the first estimation formula and the second estimation formula are obtained, for example, as follows.
  • the relationship between the temperature of the mouth portion 43 and the temperature of the pin boss portion 50 (other portion) in the state where the cooling oil is injected and the state where the cooling oil is not injected is obtained.
  • the horizontal axis is the temperature of the mouth portion 43 and the vertical axis is the temperature of the pin boss portion 50, as shown in FIG. 3, the temperature of the mouth portion 43 regardless of whether or not the cooling oil is injected. It can be seen that there is a linear relationship between the temperature and the temperature of the pin boss portion 50.
  • the first-order approximation formula of the data when the cooling oil is injected is obtained as the first estimation formula
  • the first-order approximation formula of the data when the cooling oil is not injected is obtained as the second estimation formula.
  • the coefficient ⁇ ON of the first estimation formula is smaller than the coefficient ⁇ OFF of the second estimation formula.
  • the temperature of the mouth portion 43 and the temperature of the pin boss portion 50 used for creating the first estimation formula and the second estimation formula may be values obtained by simulation or may be actual measurement values.
  • the storage unit 120 has a first time constant, a second time constant, a third time constant, a fourth time constant, a fifth time constant, a sixth time constant, a seventh time constant, and an eighth time constant. Memorize the time constant.
  • the first to eighth time constants indicate the degree of change rate of the temperature of the other part.
  • the first to eighth time constants indicate the degree of change rate of the temperature of the pin boss portion 50.
  • the first to eighth time constants are used in the calculation of the corrected other part temperature in the other part temperature estimation unit 114.
  • the first to fourth time constants are selected when the cooling oil is not injected into the piston 40.
  • the first time constant is selected when the estimated temperature of the other part is lowered, fuel injection is not performed, and the engine 10 is stopped.
  • the second time constant is selected when the estimated temperature of the other part is lowered, fuel injection is not performed, and the engine 10 is running.
  • the value of the first time constant is larger than the value of the second time constant.
  • the third time constant is selected when the estimated temperature of the other part has dropped and fuel injection is being performed.
  • the temperature of the piston 40 changes significantly with respect to the change in the fuel injection amount, and the temperature decrease rate of the pin boss portion 50 is the fuel injection. Is equal to or faster than if was not done. Therefore, the value of the third time constant is smaller than the value of the first time constant, and is equal to or smaller than the value of the second time constant.
  • the fourth time constant is selected when the estimated temperature of the other part is rising.
  • the value of the fourth time constant is larger than the value of the third time constant.
  • the fifth to eighth time constants are selected in a state where the cooling oil is injected into the piston 40.
  • the fifth time constant is selected when the estimated temperature of the other part has dropped, fuel injection has not been performed, and the engine 10 has stopped.
  • the temperature of the pin boss portion 50 drops faster than when the cooling oil is not injected into the piston 40. Therefore, the value of the fifth time constant is smaller than the value of the first time constant.
  • the sixth time constant is selected when the estimated temperature of the other part has dropped, fuel injection has not been performed, and the engine 10 is running.
  • the temperature of the pin boss portion 50 drops faster than when the cooling oil is not injected into the piston 40. Therefore, the value of the sixth time constant is smaller than the value of the second time constant.
  • the seventh time constant is selected when the estimated temperature of the other part has dropped and fuel injection is being performed.
  • the temperature of the pin boss portion 50 drops faster than when the cooling oil is not injected into the piston 40. Therefore, the value of the seventh time constant is smaller than the value of the third time constant.
  • the eighth time constant is selected when the estimated temperature of the other part is rising.
  • the temperature rise rate of the pin boss portion 50 becomes faster than in the case where the cooling oil is not injected into the piston 40. Therefore, the value of the eighth time constant is smaller than the value of the fourth time constant.
  • the acquisition unit 111 provides engine state information such as the rotation speed of the crank shaft 55 of the engine 10, the fuel injection amount to the combustion chamber 11 surrounded by the piston 40 of the engine 10, the cylinder 20 and the cylinder head 23, the fuel injection timing, and the fuel. Injection pressure, presence / absence of injection of cooling oil to piston 40, oil pressure of cooling oil, oil temperature of cooling oil, intake air temperature, intake pressure, intake air amount, intake air temperature, cooling water temperature of cylinder 20, exhaust Acquires the operation signal of the brake, the exhaust temperature, the EGR (Exhaust Gas Recirculation) gas flow rate, and the like.
  • EGR exhaust Gas Recirculation
  • the mouth temperature estimation unit 112 of the mouth portion 43 of the piston 40 is based on the rotation speed and fuel injection amount of the crankshaft 55 acquired by the acquisition unit 111 and the mouth temperature estimation map stored in the storage unit 120. Estimate the temperature.
  • the mouth temperature estimation unit 112 corrects the temperature estimated based on the mouth temperature estimation map or the like using the information such as the fuel injection timing acquired by the acquisition unit 111, and estimates the corrected value as the estimated mouth temperature. do.
  • the determination unit 113 determines whether or not the cooling oil is injected toward the piston 40 based on the engine state information acquired by the acquisition unit 111.
  • the other unit temperature estimation unit 114 uses the mouth temperature estimation unit to the first estimation formula (formula (1)) stored in the storage unit 120. By substituting the estimated mouth temperature estimated in 112, the estimated temperature of the other part is obtained.
  • the other unit temperature estimation unit 114 uses the mouth temperature estimation unit to the second estimation formula (formula (2)) stored in the storage unit 120. By substituting the estimated mouth temperature estimated in 112, the estimated temperature of the other part is obtained.
  • the estimated temperature of the other part and the actual temperature of the other part may differ depending on the state of the engine 10.
  • the difference between the estimated temperature of the other part and the actual temperature of the pin boss part 50 is remarkable.
  • the time constant indicating the degree of change in the estimated temperature of the other part changes depending on the state of the engine 10.
  • the other part temperature estimation unit 114 further corrects the estimated other part temperature by using the time constant corresponding to the state of the engine 10, and calculates the corrected other part temperature.
  • the other part temperature estimation unit 114 has a change state of the estimated other part temperature, an operating state of the engine 10, and a cooling oil injection state to the piston 40 from among a plurality of time constants stored in the storage unit 120. Select a given time constant based on. The other part temperature estimation unit 114 corrects the estimated other part temperature based on the selected predetermined time constant.
  • the other part temperature estimation unit 114 divides the difference value between the newly estimated estimated other part temperature and the estimated other part temperature estimated one cycle before by a predetermined time constant, and divides the value by the estimated other part temperature one cycle before. By adding to the temperature, the estimated temperature of other parts is corrected. Thereby, the estimated temperature of the other part can be corrected to correspond to the speed of change in the temperature of the actual pin boss part 50.
  • the temperature estimation part 114 of the other part selects a relatively small time constant. As a result, the corrected other part temperature is greatly affected by the newly estimated estimated other part temperature.
  • the temperature of the other part 114 selects a relatively large time constant.
  • the corrected other part temperature is greatly affected by the estimated other part temperature estimated in the past.
  • the other part temperature estimation unit 114 calculates the corrected other part temperature T PSC using, for example, the following equation (3).
  • the formula for calculating the temperature of the corrected other part is not limited to the formula (3).
  • T PSC T PSO + ⁇ ⁇ ( TPS-T PSO ) / ⁇ ⁇ ⁇ ⁇ (3)
  • T PSO Estimated other part temperature estimated before one cycle
  • T PS Estimated other part temperature newly estimated
  • ⁇ Predetermined value
  • ⁇ Time constant
  • the temperature control unit 130 controls the temperature of the other part based on the corrected temperature of the other part obtained by the piston temperature estimation device 110 so as to extend the life of the piston 40.
  • the temperature of the pin boss portion 50 which is an example of the other portion, is estimated. From the viewpoint of durability, it is preferable that the temperature of the pin boss portion 50 is controlled to be equal to or lower than the temperature at which the hardness is lowered. This is because when the hardness of the pin boss portion 50 decreases, cracks occur in the pin boss portion 50.
  • the piston 40 is made of an aluminum alloy, it is necessary to control the temperature of the pin boss portion 50 to 200 ° C. or lower as an example so as not to cause a decrease in the hardness of the pin boss portion 50.
  • the temperature control unit 130 has at least one of the following temperature reduction controls A, B, C, D, E, and F so that the temperature of the corrected other unit does not exceed 200 ° C., which can extend the life of the piston 40. By controlling the temperature drop, the temperature of the pin boss portion 50 is prevented from exceeding 200 ° C.
  • Temperature lowering control A When the cooling oil is not injected, the supply valve 62 is controlled to "open" to inject the cooling oil. Temperature lowering control B: When the cooling oil is injected, the variable oil pump 64 is controlled. Cooling oil injection amount per unit time is increased. Temperature lowering control C: Fuel injection amount to the combustion chamber 11 is reduced. Temperature lowering control D: Fuel injection timing to the combustion chamber 11 is delayed (the position of the piston 40 is higher than usual). Inject fuel at the timing when it becomes low) Temperature lowering control E: Increase the EGR gas flow rate Lower temperature control F: Increase the supply amount of cooling water in the cylinder 20
  • the temperature lowering control A When the temperature lowering control A is performed, the temperature of the piston 40 is lowered by cooling with the newly injected cooling oil.
  • the temperature lowering control B When the temperature lowering control B is performed, the cooling capacity of the cooling oil is improved, so that the temperature of the piston 40 is lowered.
  • the temperature lowering control C When the temperature lowering control C is performed, the amount of heat given to the piston 40 by combustion decreases, so that the temperature of the piston 40 drops.
  • the temperature lowering control D When the temperature lowering control D is performed, the fuel is injected in a state where the pressure is lower than usual, so that the amount of heat given to the piston 40 by combustion decreases, and the temperature of the piston 40 drops.
  • the temperature lowering control E When the temperature lowering control E is performed, the EGR gas is returned to the engine 10 to lower the combustion temperature, and the temperature of the piston 40 that receives heat from the combustion gas is lowered.
  • the temperature lowering control F When the temperature lowering control F is performed, the temperature of the cylinder
  • FIG. 4 is a flowchart showing an example of the operation of the piston temperature control device.
  • the acquisition unit 111 of the piston temperature control device 100 acquires engine state information (step S1).
  • the mouth temperature estimation unit 112 of the piston temperature control device 100 includes the rotation speed and fuel injection amount of the crankshaft 55 included in the engine state information acquired by the acquisition unit 111, and the mouth temperature stored in the storage unit 120.
  • the estimated mouth temperature is estimated based on the estimation map and the like (step S2).
  • the determination unit 113 of the piston temperature control device 100 determines whether or not the cooling oil is injected based on the information regarding the presence or absence of the injection of the cooling oil included in the engine state information acquired by the acquisition unit 111. Is determined (step S3).
  • the other unit temperature estimation unit 114 of the piston temperature control device 100 has the first estimation formula stored in the storage unit 120.
  • the estimated temperature of the other part is estimated based on (Equation (1)) and the estimated temperature of the mouth part (step S4).
  • step S5 when the determination unit 113 determines that the cooling oil has not been injected (step S3: NO), the other unit temperature estimation unit 114 has a second estimation formula (formula (2)) stored in the storage unit 120. )) And the estimated mouth temperature, and the estimated temperature of the other part is estimated (step S5).
  • step S4 the other part temperature estimation unit 114 determines the operating state of the engine 10 and the injection state of the cooling oil included in the engine state information acquired by the acquisition unit 111, and the estimated other part temperature.
  • a time constant is selected based on the change situation (step S6).
  • the other part temperature estimation unit 114 corrects based on the calculation formula (formula (3)), the estimated other part temperature estimated in step S4 or step S5, and the time constant selected in step S6.
  • the temperature of the other part is calculated (step S7).
  • the estimated other temperature T PSO estimated one cycle before the equation (3) does not exist.
  • the oil temperature, the estimated mouth temperature calculated separately, or a preset value may be used as the estimated other temperature T PSO .
  • the temperature control unit 130 of the piston temperature control device 100 determines whether or not the temperature of the corrected other unit exceeds the threshold value (step S8).
  • the threshold value used in step S8 is set to a temperature at which the temperature of the other part may rise and a problem may occur in the other part if the temperature lowering control is not performed while the threshold value is exceeded. ..
  • the threshold value is set to a temperature at which the temperature of the pin boss portion 50 may rise and exceed 200 ° C. if the temperature lowering control is not performed while the threshold value is exceeded. It is set.
  • the threshold value of the pin boss portion 50 may be set to 200 ° C. This is because if the temperature of the pin boss portion 50 does not exceed 200 ° C. for a long time, the possibility of cracks in the pin boss portion 50 is reduced.
  • step S8 determines that the temperature of the corrected other unit exceeds the threshold value (step S8: YES)
  • the temperature control unit 130 performs temperature decrease control of at least one of the temperature decrease controls A to F (step S9).
  • step S9 After the processing of step S9, or when it is determined that the temperature of the corrected other part does not exceed the threshold value (step S8: NO), the temperature control unit 130 determines whether or not to terminate the piston temperature control processing (step S8: NO). Step S10).
  • step S10 determines that the piston temperature control process is to be terminated, for example, when the operation of the engine 10 is completed (step S10: YES), the temperature control unit 130 terminates the process. On the other hand, when the temperature control unit 130 determines that the piston temperature control process is not terminated (step S10: NO), the piston temperature control device 100 performs the process of step S1.
  • the piston temperature estimation device 110 of the piston temperature control device 100 estimates the estimated mouth temperature of the mouth 43 of the cavity 42 of the piston 40, and estimates and others based on the estimated mouth temperature and the temperature estimation information. Estimate the temperature of the part. Therefore, the life of the piston 40 can be extended by controlling the temperature of the other part based on the estimated temperature of the other part. In particular, in order to estimate the temperature of the pin boss portion 50, which is an example of another portion, and to control the temperature decrease so that the temperature of the pin boss portion 50 does not exceed 200 ° C., the occurrence of cracks in the pin boss portion 50 is suppressed. Can be done.
  • the piston temperature estimation device 110 estimates the estimated temperature of the other part using different estimation formulas depending on whether or not the cooling oil is injected. Therefore, the estimated temperature of the other part can be estimated more appropriately depending on whether or not the piston 40 is cooled by the cooling oil.
  • the piston temperature estimation device 110 calculates the corrected other part temperature obtained by correcting the estimated other part temperature based on the time constant indicating the degree of change rate of the temperature of the other part. Therefore, the temperature of the other part at the time of estimation can be estimated more appropriately.
  • the piston temperature estimation device 110 has a predetermined time constant selected from a plurality of time constants based on the temperature change state of other parts, the rotation speed of the crankshaft 55, the fuel injection amount, and the injection state of the cooling oil. Is used to calculate the corrected temperature of the other part. Therefore, the actual temperature of other parts can be estimated accurately.
  • the second embodiment differs from the first embodiment in that the temperature of the cooling channel 44 is estimated as an example of the other part.
  • the differences will be mainly described. Since the operation of the piston temperature control device 100 is the same as that of the first embodiment, the description thereof will be omitted.
  • the piston 40 of the second embodiment is different from the piston 40 of the first embodiment in that it is made of steel or cast iron.
  • the storage unit 120 stores the first estimation formula represented by the above formula (1) and the second estimation formula represented by the above formula (2).
  • the coefficients ⁇ ON , ⁇ OFF , ⁇ ON , ⁇ OFF of the second embodiment are different from the values of the first embodiment.
  • the cooling channel 44 is closer to the mouth portion 43 than the pin boss portion 50. Therefore, the coefficients ⁇ ON and ⁇ OFF of the cooling channel 44 are larger than the coefficients ⁇ ON and ⁇ OFF of the pin boss portion 50.
  • the first estimation formula and the second estimation formula are the same as the first estimation formula and the second estimation formula of the first embodiment, in a state where the cooling oil is injected and the cooling oil is injected. It can be obtained based on the relationship between the temperature of the mouth portion 43 and the temperature of the cooling channel 44 in the non-exposed state.
  • the storage unit 120 stores the first to eighth time constants.
  • the first to eighth time constants indicate the degree of change rate of the temperature of the cooling channel 44. Therefore, the first to eighth time constants of the second embodiment are different from the values of the first embodiment.
  • the other part temperature estimation unit 114 estimates the temperature of the cooling channel 44 as the estimated other part temperature based on the first and second estimation formulas stored in the storage unit 120 and the estimated mouth portion temperature. For example, the other part temperature estimation unit 114 estimates the temperature of a part of the inner wall of the cooling channel 44.
  • the temperature control unit 130 controls the temperature of the cooling channel 44 so that the life of the piston 40 can be extended.
  • the temperature is controlled to be equal to or lower than the temperature at which the cooling oil is carbonized and the fixing proceeds. If the amount of carbonized component of the cooling oil fixed in the cooling channel 44 increases, the amount of heat transfer on the inner surface of the cooling channel 44 decreases, the amount of cooling oil that can be circulated decreases, and the cooling efficiency of the piston 40 decreases. Because.
  • the piston 40 is made of steel, it is necessary to control the temperature of the cooling channel 44 to 300 ° C. or lower as an example so that the cooling oil does not carbonize and the fixing does not proceed. Therefore, the threshold value used in step S8 of FIG.
  • step S8 when the temperature of the corrected other unit exceeds the threshold value, the temperature control unit 130 controls the temperature decrease of at least one of the above-mentioned temperature decrease controls A, B, C, D, E, and F.
  • the temperature of the cooling channel 44 should not exceed 300 ° C.
  • the threshold value of the cooling channel 44 may be set to 300 ° C. This is because if the temperature of the cooling channel 44 does not exceed 300 ° C. for a long time, there is less possibility that the cooling oil will adhere to the cooling channel 44.
  • the piston temperature estimation device 110 of the piston temperature control device 100 estimates the estimated mouth temperature of the mouth 43 of the cavity 42 of the piston 40, and based on the estimated mouth temperature and the temperature estimation information, the cooling channel. Estimate the temperature of 44. Therefore, by controlling the temperature of the cooling channel 44 based on the appropriately estimated temperature of the cooling channel 44, it is possible to suppress an increase in the amount of the carbonized component of the cooling oil adhered to the cooling channel 44. can. As a result, the life of the piston 40 can be extended.
  • the portion other than the pin boss portion 50 and the cooling channel 44 may be used as a portion for estimating the temperature by the piston temperature estimation device 110.
  • the other portion may be a ring groove 47.
  • the temperature of the ring groove 47 is controlled to be equal to or lower than the temperature at which the piston ring 48 adheres.
  • the function of the ring is lost, which causes deterioration of the flow rate of blow-by gas and the sliding resistance of the contact surface between the piston ring 48 and the cylinder 20. Therefore, if the threshold value used in step S8 of FIG.
  • step S8 when the temperature of the corrected other unit exceeds the threshold value, the temperature control unit 130 controls the temperature decrease of at least one of the above-mentioned temperature decrease controls A, B, C, D, and E, thereby performing the piston ring. It suffices to prevent 48 from sticking to the ring groove 47.
  • a portion other than the mouth portion 43 constituting the cavity 42 that is, the side surface portion 42A and the bottom surface portion 42B of the cavity 42 may be used, or the piston upper portion 41 may be used.
  • the side surface portion 41A (the side surface portion on the cavity 42 side of the ring groove 47 in the piston 40) may be used.
  • the coefficients ⁇ ON , ⁇ OFF , ⁇ ON , ⁇ OFF and the first to eighth time constants of the first and second estimation formulas are the ring groove 47, the side surface portion 42A of the cavity 42, the bottom surface portion 42B, and the piston. It may be appropriately set according to the temperature change characteristic of the side surface portion 41A of the upper portion 41.
  • the other part temperature estimation unit 114 may estimate the estimated other part temperature using the same estimation formula regardless of whether or not the cooling oil is injected.
  • the linear approximation formulas of all the data when the cooling oil is injected and when the cooling oil is not injected, which are shown in FIG. 3, are obtained as estimation formulas and estimated by this estimation formula. Substitute the mouth temperature.
  • the first to eighth time constants were used properly, but it is not limited to this.
  • the time constant may be further subdivided based on the temperature change state of other parts, the engine operating state, and the injection state of the cooling oil. Other parameters may be taken into consideration when subdividing the time constant.
  • the temperature drop control may be performed based on whether or not the estimated temperature of the other part exceeds the threshold value without providing the function of correcting the estimated temperature of the other part in the other part temperature estimation unit 114.
  • the supply valve 62 is not limited to a configuration that actively operates under the control of the temperature control unit 130.
  • a valve provided with a valve and a spring and opened and closed by hydraulic pressure is applied, and the hydraulic pressure of the oil flowing through the oil passage 65 is applied. When it becomes high, the valve may be passively "opened” to inject cooling oil from the nozzle 63.
  • an oil pump that cannot change the flow rate of oil may be used, but in this case, the temperature lowering control B cannot be performed.
  • the configuration of the present disclosure can be applied to a piston temperature estimation device, a piston temperature control device, a piston temperature estimation method, and a piston temperature control method.

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  • Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Lubrication Of Internal Combustion Engines (AREA)

Abstract

Provided are a piston temperature estimation device, a piston temperature control device, a piston temperature estimation method, and a piston temperature control method with which the temperature of a piston can be appropriately estimated so that the life of the piston can be extended.　A piston temperature estimation device (110) comprises a mouth temperature estimation unit (112) that estimates the temperature of a mouth part of a cavity of a piston, and an other-part temperature estimation unit (114) that estimates the temperature of another part on the basis of the temperature of the mouth part estimated by the mouth temperature estimation unit.

Description

ピストン温度推定装置、ピストン温度制御装置、ピストン温度推定方法およびピストン温度制御方法Piston temperature estimation device, piston temperature control device, piston temperature estimation method and piston temperature control method
　本開示は、ピストン温度推定装置、ピストン温度制御装置、ピストン温度推定方法およびピストン温度制御方法に関する。 The present disclosure relates to a piston temperature estimation device, a piston temperature control device, a piston temperature estimation method, and a piston temperature control method.
　従来、内燃機関のピストンの温度を推定して、推定した温度に応じてピストンの温度を制御する方法が知られている（例えば、特許文献１～２参照）。 Conventionally, a method of estimating the temperature of the piston of an internal combustion engine and controlling the temperature of the piston according to the estimated temperature is known (see, for example, Patent Documents 1 and 2).
　特許文献１に記載の方法では、燃料噴射量と、エンジン回転速度と、に基づいて、ピストンの頂面温度を推定する。推定したピストンの頂面温度に基づいて、オイルジェットを制御する。 In the method described in Patent Document 1, the top surface temperature of the piston is estimated based on the fuel injection amount and the engine rotation speed. The oil jet is controlled based on the estimated top surface temperature of the piston.
　特許文献２に記載の方法では、燃焼室からピストンに対して生じる第２の冷却損失と、燃焼ガスの温度と、に基づいて、ピストンの温度を算出する。算出したピストンの温度に基づいて、オイルジェットを制御する。 In the method described in Patent Document 2, the temperature of the piston is calculated based on the second cooling loss generated from the combustion chamber to the piston and the temperature of the combustion gas. The oil jet is controlled based on the calculated piston temperature.
日本国特開２００２－１４７２３６号公報Japanese Patent Application Laid-Open No. 2002-147236 日本国特開２０１８－１３１９４１号公報Japanese Patent Application Laid-Open No. 2018-131941
　ピストンの温度には分布があり、キャビティの口元部の温度が最も高く、口元部以外の他部の温度と口元部の温度とは異なっている。ピストンの長寿命化を図るためには、ピストンの各部位を適切な温度に制御して、当該各部位の劣化や破損等を抑制する必要がある。しかしながら、特許文献１に記載の方法では、温度の推定箇所がピストンの頂面であり、特許文献２に記載の方法では、温度の推定箇所がピストンのいずれの箇所であるかが明確でない。このため、特許文献１，２に記載の方法では、ピストンの口元部以外の所定の部位の温度を推定して、当該所定の部位を適切な温度に制御することが行われておらず、ピストンの長寿命化を図れないおそれがある。 There is a distribution in the temperature of the piston, the temperature of the mouth of the cavity is the highest, and the temperature of other parts other than the mouth is different from the temperature of the mouth. In order to extend the life of the piston, it is necessary to control each part of the piston to an appropriate temperature to suppress deterioration or breakage of each part. However, in the method described in Patent Document 1, the temperature estimation point is the top surface of the piston, and in the method described in Patent Document 2, it is not clear which part of the piston the temperature estimation point is. Therefore, in the methods described in Patent Documents 1 and 2, the temperature of a predetermined portion other than the mouth portion of the piston is estimated and the predetermined portion is not controlled to an appropriate temperature, and the piston is not used. There is a risk that the life of the piston cannot be extended.
　本開示の目的は、ピストンの長寿命化を図れるようにピストンの温度を適切に推定できるピストン温度推定装置、ピストン温度制御装置、ピストン温度推定方法およびピストン温度制御方法を提供することである。 An object of the present disclosure is to provide a piston temperature estimation device, a piston temperature control device, a piston temperature estimation method, and a piston temperature control method that can appropriately estimate the piston temperature so as to extend the life of the piston.
　本開示に係るピストン温度推定装置は、内燃機関を構成するピストンのキャビティの口元部の温度を推定する口元温度推定部と、前記口元温度推定部で推定された前記口元部の温度に基づいて、前記ピストンにおける前記口元部以外の他部の温度を推定する他部温度推定部と、を備える。 The piston temperature estimation device according to the present disclosure is based on a mouth temperature estimation unit that estimates the temperature of the mouth portion of the cavity of the piston constituting the internal combustion engine and the temperature of the mouth portion estimated by the mouth temperature estimation unit. The piston includes a temperature estimation unit for estimating the temperature of other parts other than the mouth portion.
　本開示に係るピストン温度制御装置は、上述のピストン温度推定装置と、前記ピストン温度推定装置の処理で得られた前記他部の温度に基づいて、前記他部の温度を制御する温度制御部と、を備える。 The piston temperature control device according to the present disclosure includes the above-mentioned piston temperature estimation device and a temperature control unit that controls the temperature of the other part based on the temperature of the other part obtained by the processing of the piston temperature estimation device. , Equipped with.
　本開示に係るピストン温度推定方法は、内燃機関を構成するピストンのキャビティの口元部の温度を推定するステップと、前記推定された前記口元部の温度に基づいて、前記ピストンにおける前記口元部以外の他部の温度を推定するステップと、を実行する。 The piston temperature estimation method according to the present disclosure is based on a step of estimating the temperature of the mouth portion of the cavity of the piston constituting the internal combustion engine and the estimated temperature of the mouth portion, other than the mouth portion of the piston. Perform the steps of estimating the temperature of the other part.
　本開示に係るピストン温度制御方法は、上述のピストン温度推定方法を実行するステップと、前記ピストン温度推定方法の実行で得られた前記他部の温度に基づいて、前記他部の温度を制御するステップと、を実行する。 The piston temperature control method according to the present disclosure controls the temperature of the other part based on the step of executing the above-mentioned piston temperature estimation method and the temperature of the other part obtained by executing the piston temperature estimation method. Step and perform.
　本開示によれば、ピストンの長寿命化を図れるようにピストンの温度を適切に推定できるピストン温度推定装置、ピストン温度制御装置、ピストン温度推定方法およびピストン温度制御方法を提供することができる。 According to the present disclosure, it is possible to provide a piston temperature estimation device, a piston temperature control device, a piston temperature estimation method, and a piston temperature control method that can appropriately estimate the piston temperature so as to extend the life of the piston.
本開示の第１の実施の形態および第２の実施の形態に係るエンジンの概略構成を示す断面図Sectional drawing which shows the schematic structure of the engine which concerns on 1st Embodiment and 2nd Embodiment of this disclosure. 本開示の第１の実施の形態および第２の実施の形態に係るピストン温度制御装置の構成を示すブロック図The block diagram which shows the structure of the piston temperature control apparatus which concerns on 1st Embodiment and 2nd Embodiment of this disclosure. 本開示の第１の実施の形態および第２の実施の形態に係る冷却用オイルが噴射されている状態および冷却用オイルが噴射されていない状態における口元部の温度と他部の温度との関係を示すグラフRelationship between the temperature of the mouth portion and the temperature of the other portion in the state where the cooling oil is injected and the state where the cooling oil is not injected according to the first embodiment and the second embodiment of the present disclosure. Graph showing 本開示の第１の実施の形態および第２の実施の形態に係るピストン温度制御装置の動作の一例を示すフローチャートA flowchart showing an example of the operation of the piston temperature control device according to the first embodiment and the second embodiment of the present disclosure.
［第１の実施の形態］
　以下、本開示の第１の実施の形態について説明する。 [First Embodiment]
Hereinafter, the first embodiment of the present disclosure will be described.
〔エンジンの概略構成〕
　まず、本開示のピストン温度制御装置によって制御されるエンジンの概略構成について説明する。エンジンは、内燃機関の一例である。図１は、エンジンの概略構成を示す断面図である。 [Outline configuration of engine]
First, a schematic configuration of an engine controlled by the piston temperature control device of the present disclosure will be described. The engine is an example of an internal combustion engine. FIG. 1 is a cross-sectional view showing a schematic configuration of an engine.
　図１に示すエンジン１０は、例えば、トラックのような自動車に搭載されるディーゼルエンジンである。エンジン１０は、シリンダ２０と、ピストン４０と、を備える。なお、本開示の内燃機関は、ディーゼルエンジンに限定されず、ガソリンエンジン等であっても良い。 The engine 10 shown in FIG. 1 is a diesel engine mounted on an automobile such as a truck. The engine 10 includes a cylinder 20 and a piston 40. The internal combustion engine of the present disclosure is not limited to a diesel engine, and may be a gasoline engine or the like.
　シリンダ２０には、冷却通路２１が設けられている。冷却通路２１には、シリンダ２０の冷却水が供給される。シリンダ２０の内周面には、ライナ２２が設けられている。なお、ライナ２２は設けられていなくても良い。シリンダ２０の上部のシリンダヘッド２３には、インジェクタ２４が、ピストン４０の頂面中央に対向するように設けられている。シリンダヘッド２３には、インジェクタ２４の左右に位置するように、吸気ポート２５および排気ポート２６がそれぞれ設けられている。吸気ポート２５および排気ポート２６には、それぞれ吸気用バルブ２７および排気用バルブ２８が設けられている。 The cylinder 20 is provided with a cooling passage 21. The cooling water of the cylinder 20 is supplied to the cooling passage 21. A liner 22 is provided on the inner peripheral surface of the cylinder 20. The liner 22 may not be provided. An injector 24 is provided on the cylinder head 23 above the cylinder 20 so as to face the center of the top surface of the piston 40. The cylinder head 23 is provided with an intake port 25 and an exhaust port 26 so as to be located on the left and right sides of the injector 24. The intake port 25 and the exhaust port 26 are provided with an intake valve 27 and an exhaust valve 28, respectively.
　ピストン４０は、ライナ２２に沿ってシリンダ２０内を往復運動が可能なように設置されている。ピストン４０は、例えばアルミニウム合金等で構成されている。 The piston 40 is installed so as to be able to reciprocate in the cylinder 20 along the liner 22. The piston 40 is made of, for example, an aluminum alloy.
　ピストン４０のピストン上部４１の頂面には、キャビティ４２が設けられている。ピストン上部４１には、周方向に沿って形成されたクーリングチャンネル４４と、クーリングチャンネル４４にオイルを導入するための導入孔４５と、クーリングチャンネル４４からオイルを排出するための排出孔４６と、が設けられている。クーリングチャンネル４４には、オイルジェット６１から、導入孔４５を介してオイルが導入される。この導入されたオイルがクーリングチャンネル４４を循環して、排出孔４６から排出されることによって、ピストン４０が効率的に冷却される。なお、オイルジェット６１から噴射されるオイルを「冷却用オイル」という場合がある。ピストン４０のピストン上部４１の外周には、周方向に沿って形成されたリング溝４７が設けられている。リング溝４７には、ライナ２２と摺接するピストンリング４８が装着されている。 A cavity 42 is provided on the top surface of the piston upper portion 41 of the piston 40. The piston upper portion 41 has a cooling channel 44 formed along the circumferential direction, an introduction hole 45 for introducing oil into the cooling channel 44, and a discharge hole 46 for discharging oil from the cooling channel 44. It is provided. Oil is introduced into the cooling channel 44 from the oil jet 61 through the introduction hole 45. The introduced oil circulates in the cooling channel 44 and is discharged from the discharge hole 46, so that the piston 40 is efficiently cooled. The oil injected from the oil jet 61 may be referred to as "cooling oil". A ring groove 47 formed along the circumferential direction is provided on the outer periphery of the piston upper portion 41 of the piston 40. A piston ring 48 that is in sliding contact with the liner 22 is mounted on the ring groove 47.
　ピストン４０のスカート部４９には、互いに対向する一対のピンボス部５０（図１では一方のピンボス部５０のみを図示）が設けられている。一対のピンボス部５０には、ピストン４０の中心側からピストン外周側に向かって貫通するピン嵌入孔５１がそれぞれ設けられている。ピン嵌入孔５１には、ピストンピン５２を介してコンロッド５３の上端部が接続されている。コンロッド５３の下端部は、クランクピン５４を介して、クランクシャフト５５に接続されている。クランクシャフト５５によって、ピストン４０の往復運動が回転運動に変換される。 The skirt portion 49 of the piston 40 is provided with a pair of pin boss portions 50 facing each other (only one pin boss portion 50 is shown in FIG. 1). The pair of pin boss portions 50 are each provided with pin fitting holes 51 penetrating from the center side of the piston 40 toward the outer peripheral side of the piston. The upper end of the connecting rod 53 is connected to the pin fitting hole 51 via the piston pin 52. The lower end of the connecting rod 53 is connected to the crankshaft 55 via the crankpin 54. The crankshaft 55 converts the reciprocating motion of the piston 40 into a rotary motion.
　オイルジェット６１は、供給バルブ６２と、ノズル６３と、を備える。供給バルブ６２が「閉」のとき、ノズル６３から冷却用オイルは噴射されない。供給バルブ６２が「開」のとき、ノズル６３から冷却用オイルが噴射される。なお、オイルジェット６１の構成については、公知であるため、詳細な説明を省略する。 The oil jet 61 includes a supply valve 62 and a nozzle 63. When the supply valve 62 is “closed”, the cooling oil is not injected from the nozzle 63. When the supply valve 62 is “open”, cooling oil is injected from the nozzle 63. Since the configuration of the oil jet 61 is known, detailed description thereof will be omitted.
　オイルジェット６１と図示しないオイルパンとの間には、油路６５が設けられている。油路６５には、オイルの流量を変化させることができる可変オイルポンプ６４が設けられている。油路６５における可変オイルポンプ６４よりもオイルジェット６１側の部分は、エンジン１０の潤滑が必要な部位にオイルを供給する図示しない供給路に接続されている。可変オイルポンプ６４は、オイルパンに貯留されたオイル（潤滑油）を、潤滑が必要な部位やオイルジェット６１等に供給する。 An oil passage 65 is provided between the oil jet 61 and an oil pan (not shown). The oil passage 65 is provided with a variable oil pump 64 capable of changing the flow rate of oil. The portion of the oil passage 65 on the oil jet 61 side of the variable oil pump 64 is connected to a supply passage (not shown) that supplies oil to a portion of the engine 10 that requires lubrication. The variable oil pump 64 supplies the oil (lubricating oil) stored in the oil pan to a portion requiring lubrication, an oil jet 61, or the like.
〔ピストン温度制御装置の構成〕
　次に、ピストン温度制御装置の構成について説明する。図２は、ピストン温度制御装置の構成を示すブロック図である。図３は、冷却用オイルが噴射されている状態および冷却用オイルが噴射されていない状態における口元部の温度と他部の温度との関係を示すグラフである。 [Structure of piston temperature control device]
Next, the configuration of the piston temperature control device will be described. FIG. 2 is a block diagram showing the configuration of the piston temperature control device. FIG. 3 is a graph showing the relationship between the temperature of the mouth portion and the temperature of the other portion in the state where the cooling oil is injected and the state where the cooling oil is not injected.
　図２に示すように、ピストン温度制御装置１００は、ピストン温度推定装置１１０と、記憶部１２０と、温度制御部１３０と、を備える。ピストン温度推定装置１１０および温度制御部１３０は、ハードウェアとして、例えば、ＣＰＵ（Central Processing Unit）、ＲＯＭ（Read Only Memory）、ＲＡＭ（Random Access Memory）等を有する。以下において説明するピストン温度推定装置１１０および温度制御部１３０の各機能は、ＣＰＵがＲＯＭから読み出したコンピュータプログラムをＲＡＭ上で実行することにより実現される。 As shown in FIG. 2, the piston temperature control device 100 includes a piston temperature estimation device 110, a storage unit 120, and a temperature control unit 130. The piston temperature estimation device 110 and the temperature control unit 130 have, for example, a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like as hardware. Each function of the piston temperature estimation device 110 and the temperature control unit 130 described below is realized by executing a computer program read from the ROM by the CPU on the RAM.
　ピストン温度推定装置１１０は、取得部１１１と、口元温度推定部１１２と、判定部１１３と、他部温度推定部１１４と、を備える。 The piston temperature estimation device 110 includes an acquisition unit 111, a mouth temperature estimation unit 112, a determination unit 113, and another unit temperature estimation unit 114.
　取得部１１１は、各種センサからエンジンの状態を代表するエンジン状態情報を取得する。 The acquisition unit 111 acquires engine status information representing the engine status from various sensors.
　口元温度推定部１１２は、ピストン４０のキャビティ４２の口元部４３の温度を推定する。以下、口元温度推定部１１２で推定された口元部４３の温度を、「推定口元部温度」という場合がある。 The mouth temperature estimation unit 112 estimates the temperature of the mouth portion 43 of the cavity 42 of the piston 40. Hereinafter, the temperature of the mouth portion 43 estimated by the mouth temperature estimation unit 112 may be referred to as “estimated mouth portion temperature”.
　判定部１１３は、オイルジェット６１がピストン４０に向けて冷却用オイルを噴射しているか否かを判定する。 The determination unit 113 determines whether or not the oil jet 61 injects cooling oil toward the piston 40.
　他部温度推定部１１４は、記憶部１２０に記憶された温度推定用情報と、口元温度推定部１１２で推定された推定口元部温度と、に基づいて、ピストン４０における口元部４３以外の他部の温度を推定する。以下、他部温度推定部１１４で推定された他部の温度を、「推定他部温度」という場合がある。本第１の実施の形態では、他部温度推定部１１４は、他部の一例であるピンボス部５０の温度を推定する。例えば、他部温度推定部１１４は、ピンボス部５０におけるピン嵌入孔５１の上縁部の温度を推定する。他部温度推定部１１４は、記憶部１２０に記憶されている複数の時定数から、所定の時定数を選択し、選択した時定数を用いて推定他部温度を補正する。以下、時定数を用いて補正された他部の温度を、「補正他部温度」という場合がある。 The other unit temperature estimation unit 114 is a unit other than the mouth unit 43 in the piston 40 based on the temperature estimation information stored in the storage unit 120 and the estimated mouth unit temperature estimated by the mouth temperature estimation unit 112. Estimate the temperature of. Hereinafter, the temperature of the other part estimated by the other part temperature estimation unit 114 may be referred to as “estimated other part temperature”. In the first embodiment, the other unit temperature estimation unit 114 estimates the temperature of the pin boss unit 50, which is an example of the other unit. For example, the other portion temperature estimation unit 114 estimates the temperature of the upper edge portion of the pin fitting hole 51 in the pin boss portion 50. The other unit temperature estimation unit 114 selects a predetermined time constant from a plurality of time constants stored in the storage unit 120, and corrects the estimated other unit temperature using the selected time constant. Hereinafter, the temperature of the other part corrected by using the time constant may be referred to as “corrected other part temperature”.
　記憶部１２０は、口元温度推定マップを記憶する。口元温度推定マップは、クランクシャフト５５の回転速度と、燃料噴射量と、口元部４３の推定温度と、の関係を示すマップである。口元温度推定マップは、口元温度推定部１１２における推定口元部温度の推定に用いられる。 The storage unit 120 stores the mouth temperature estimation map. The mouth temperature estimation map is a map showing the relationship between the rotation speed of the crankshaft 55, the fuel injection amount, and the estimated temperature of the mouth portion 43. The mouth temperature estimation map is used for estimating the estimated mouth temperature in the mouth temperature estimation unit 112.
　記憶部１２０は、以下の式（１）で表される第１の推定式と、式（２）で表される第２の推定式と、を記憶する。第１の推定式は、第１の推定情報の一例であり、第２の推定式は、第２の推定情報の一例である。第１の推定式および第２の推定式によって、温度推定用情報が構成される。第１の推定式および第２の推定式は、他部温度推定部１１４における推定他部温度の推定に用いられる。なお、第１の推定式および第２の推定式は、式（１），（２）に限定されない。また、第１の推定情報および第２の推定情報は、口元温度推定マップのようなマップ形式であってもよい。
　　ＴON＝αON×ＴK＋βON　・・・　（１）
　　ＴOFF＝αOFF×ＴK＋βOFF　・・・　（２）
　　　ＴON：冷却用オイルが噴射されているときの推定他部温度
　　　αON，βON：冷却用オイルが噴射されているときの係数
　　　ＴK：推定口元部温度
　　　ＴOFF：冷却用オイルが噴射されていないときの推定他部温度
　　　αOFF，βOFF：冷却用オイルが噴射されていないときの係数 The storage unit 120 stores the first estimation formula represented by the following formula (1) and the second estimation formula represented by the formula (2). The first estimation formula is an example of the first estimation information, and the second estimation formula is an example of the second estimation information. The temperature estimation information is composed of the first estimation formula and the second estimation formula. The first estimation formula and the second estimation formula are used for estimating the estimated temperature of the other part in the other part temperature estimation unit 114. The first estimation formula and the second estimation formula are not limited to the formulas (1) and (2). Further, the first estimation information and the second estimation information may be in a map format such as a mouth temperature estimation map.
T ON = α ON × TK + β ON・ ・ ・ (1)
T OFF = α OFF × TK + β OFF・ ・ ・ (2)
T ON : Estimated temperature of other parts when cooling oil is injected α ON, β ON : Coefficient when cooling oil is injected TK : Estimated mouth temperature T OFF : Cooling oil is injected Estimated temperature of other parts when not in use α OFF, β OFF : Coefficient when cooling oil is not injected
　第１の推定式および第２の推定式は、例えば、以下のようにして求められる。冷却用オイルが噴射されている状態および冷却用オイルが噴射されていない状態における、口元部４３の温度と、ピンボス部５０（他部）の温度との関係を求める。横軸を口元部４３の温度、縦軸をピンボス部５０の温度としたグラフを作成すると、図３に示すように、冷却用オイルが噴射されているか否かに関係なく、口元部４３の温度と、ピンボス部５０の温度との間には、線形の関係があることがわかる。冷却用オイルが噴射されているときのデータの一次近似式を第１の推定式として求め、冷却用オイルが噴射されていないときのデータの一次近似式を第２の推定式として求める。口元部４３の温度が同じ場合、冷却用オイルが噴射されているときのピンボス部５０の温度は、冷却用オイルが噴射されていないときのピンボス部５０の温度よりも低くなる。このため、第１の推定式の係数αONは、第２の推定式の係数αOFFよりも小さくなる。なお、第１の推定式および第２の推定式の作成に用いる口元部４３の温度およびピンボス部５０の温度は、シミュレーションで求めた値であっても良いし、実測値であっても良い。 The first estimation formula and the second estimation formula are obtained, for example, as follows. The relationship between the temperature of the mouth portion 43 and the temperature of the pin boss portion 50 (other portion) in the state where the cooling oil is injected and the state where the cooling oil is not injected is obtained. When a graph is created in which the horizontal axis is the temperature of the mouth portion 43 and the vertical axis is the temperature of the pin boss portion 50, as shown in FIG. 3, the temperature of the mouth portion 43 regardless of whether or not the cooling oil is injected. It can be seen that there is a linear relationship between the temperature and the temperature of the pin boss portion 50. The first-order approximation formula of the data when the cooling oil is injected is obtained as the first estimation formula, and the first-order approximation formula of the data when the cooling oil is not injected is obtained as the second estimation formula. When the temperature of the mouth portion 43 is the same, the temperature of the pin boss portion 50 when the cooling oil is injected is lower than the temperature of the pin boss portion 50 when the cooling oil is not injected. Therefore, the coefficient α ON of the first estimation formula is smaller than the coefficient α OFF of the second estimation formula. The temperature of the mouth portion 43 and the temperature of the pin boss portion 50 used for creating the first estimation formula and the second estimation formula may be values obtained by simulation or may be actual measurement values.
　記憶部１２０は、第１の時定数、第２の時定数、第３の時定数、第４の時定数、第５の時定数、第６の時定数、第７の時定数および第８の時定数を記憶する。第１～第８の時定数は、他部の温度の変化速度の度合いを示す。本第１の実施の形態では、第１～第８の時定数は、ピンボス部５０の温度の変化速度の度合いを示す。第１～第８の時定数は、他部温度推定部１１４における補正他部温度の算出に用いられる。 The storage unit 120 has a first time constant, a second time constant, a third time constant, a fourth time constant, a fifth time constant, a sixth time constant, a seventh time constant, and an eighth time constant. Memorize the time constant. The first to eighth time constants indicate the degree of change rate of the temperature of the other part. In the first embodiment, the first to eighth time constants indicate the degree of change rate of the temperature of the pin boss portion 50. The first to eighth time constants are used in the calculation of the corrected other part temperature in the other part temperature estimation unit 114.
　第１～第４の時定数は、ピストン４０に冷却用オイルが噴射されていない状態のときに選択される。 The first to fourth time constants are selected when the cooling oil is not injected into the piston 40.
　第１の時定数は、推定他部温度が低下し、燃料噴射が行われておらず、かつ、エンジン１０が停止している場合に選択される。第２の時定数は、推定他部温度が低下し、燃料噴射が行われておらず、かつ、エンジン１０が運転している場合に選択される。 The first time constant is selected when the estimated temperature of the other part is lowered, fuel injection is not performed, and the engine 10 is stopped. The second time constant is selected when the estimated temperature of the other part is lowered, fuel injection is not performed, and the engine 10 is running.
　推定他部温度が低下し、燃料噴射が行われておらず、かつ、エンジン１０が運転している場合には、冷却オイルおよび冷却水がエンジン１０内を循環するので、ピンボス部５０の温度の低下速度は速くなる。 When the estimated temperature of the other part is lowered, fuel injection is not performed, and the engine 10 is operating, the cooling oil and the cooling water circulate in the engine 10, so that the temperature of the pin boss part 50 is increased. The rate of decline will be faster.
　一方、推定他部温度が低下し、燃料噴射が行われておらず、かつ、エンジン１０が停止している場合には、冷却オイルおよび冷却水の循環が停止する。このため、ピンボス部５０の温度の低下速度は遅くなる。したがって、第１の時定数の値は、第２の時定数の値よりも大きい。 On the other hand, when the estimated temperature of the other part drops, fuel injection is not performed, and the engine 10 is stopped, the circulation of the cooling oil and the cooling water is stopped. Therefore, the rate of decrease in the temperature of the pin boss portion 50 becomes slow. Therefore, the value of the first time constant is larger than the value of the second time constant.
　第３の時定数は、推定他部温度が低下し、燃料噴射が行われている場合に選択される。燃料噴射が行われている場合には、エンジン１０は燃料を燃焼させているので、燃料噴射量の変化に対してピストン４０の温度の変化が大きく、ピンボス部５０の温度の低下速度は燃料噴射が行われていない場合と同等あるいは速くなる。したがって、第３の時定数の値は、第１の時定数の値よりも小さく、第２の時定数と同等あるいは小さい。 The third time constant is selected when the estimated temperature of the other part has dropped and fuel injection is being performed. When fuel injection is performed, since the engine 10 burns fuel, the temperature of the piston 40 changes significantly with respect to the change in the fuel injection amount, and the temperature decrease rate of the pin boss portion 50 is the fuel injection. Is equal to or faster than if was not done. Therefore, the value of the third time constant is smaller than the value of the first time constant, and is equal to or smaller than the value of the second time constant.
　第４の時定数は、推定他部温度が上昇している場合に選択される。第４の時定数の値は、第３の時定数の値よりも大きい。 The fourth time constant is selected when the estimated temperature of the other part is rising. The value of the fourth time constant is larger than the value of the third time constant.
　第５～第８の時定数は、ピストン４０に冷却用オイルが噴射されている状態に選択される。 The fifth to eighth time constants are selected in a state where the cooling oil is injected into the piston 40.
　第５の時定数は、推定他部温度が低下し、燃料噴射が行われておらず、かつ、エンジン１０が停止している場合に選択される。ピストン４０に冷却用オイルが噴射されている場合には、ピストン４０に冷却用オイルが噴射されてない場合に比べて、ピンボス部５０の温度の低下速度は速くなる。したがって、第５の時定数の値は、第１の時定数の値よりも小さい。 The fifth time constant is selected when the estimated temperature of the other part has dropped, fuel injection has not been performed, and the engine 10 has stopped. When the cooling oil is injected into the piston 40, the temperature of the pin boss portion 50 drops faster than when the cooling oil is not injected into the piston 40. Therefore, the value of the fifth time constant is smaller than the value of the first time constant.
　第６の時定数は、推定他部温度が低下し、燃料噴射が行われておらず、かつ、エンジン１０が運転している場合に選択される。ピストン４０に冷却用オイルが噴射されている場合には、ピストン４０に冷却用オイルが噴射されてない場合に比べて、ピンボス部５０の温度の低下速度は速くなる。したがって、第６の時定数の値は、第２の時定数の値よりも小さい。 The sixth time constant is selected when the estimated temperature of the other part has dropped, fuel injection has not been performed, and the engine 10 is running. When the cooling oil is injected into the piston 40, the temperature of the pin boss portion 50 drops faster than when the cooling oil is not injected into the piston 40. Therefore, the value of the sixth time constant is smaller than the value of the second time constant.
　第７の時定数は、推定他部温度が低下し、燃料噴射が行われている場合に選択される。ピストン４０に冷却用オイルが噴射されている場合には、ピストン４０に冷却用オイルが噴射されてない場合に比べて、ピンボス部５０の温度の低下速度は速くなる。したがって、第７の時定数の値は、第３の時定数の値よりも小さい。 The seventh time constant is selected when the estimated temperature of the other part has dropped and fuel injection is being performed. When the cooling oil is injected into the piston 40, the temperature of the pin boss portion 50 drops faster than when the cooling oil is not injected into the piston 40. Therefore, the value of the seventh time constant is smaller than the value of the third time constant.
　第８の時定数は、推定他部温度が上昇している場合に選択される。ピストン４０に冷却用オイルが噴射されている場合には、ピストン４０に冷却用オイルが噴射されてない場合に比べて、ピンボス部５０の温度の上昇速度は速くなる。したがって、第８の時定数の値は、第４の時定数の値よりも小さい。 The eighth time constant is selected when the estimated temperature of the other part is rising. When the cooling oil is injected into the piston 40, the temperature rise rate of the pin boss portion 50 becomes faster than in the case where the cooling oil is not injected into the piston 40. Therefore, the value of the eighth time constant is smaller than the value of the fourth time constant.
　以下、取得部１１１、口元温度推定部１１２、判定部１１３および他部温度推定部１１４の詳細な構成について説明する。 Hereinafter, the detailed configuration of the acquisition unit 111, the mouth temperature estimation unit 112, the determination unit 113, and the other unit temperature estimation unit 114 will be described.
（取得部１１１）
　取得部１１１は、エンジン状態情報として、エンジン１０のクランクシャフト５５の回転速度、エンジン１０のピストン４０、シリンダ２０およびシリンダヘッド２３に囲まれた燃焼室１１への燃料噴射量、燃料噴射時期、燃料噴射圧力、ピストン４０への冷却用オイルの噴射の有無、冷却用オイルの油圧、冷却用オイルの油温、吸気温度、吸気圧力、吸入空気量、吸入空気温度、シリンダ２０の冷却水温度、排気ブレーキの動作信号、排気温度、ＥＧＲ（Exhaust Gas Recirculation）ガス流量等を取得する。 (Acquisition unit 111)
The acquisition unit 111 provides engine state information such as the rotation speed of the crank shaft 55 of the engine 10, the fuel injection amount to the combustion chamber 11 surrounded by the piston 40 of the engine 10, the cylinder 20 and the cylinder head 23, the fuel injection timing, and the fuel. Injection pressure, presence / absence of injection of cooling oil to piston 40, oil pressure of cooling oil, oil temperature of cooling oil, intake air temperature, intake pressure, intake air amount, intake air temperature, cooling water temperature of cylinder 20, exhaust Acquires the operation signal of the brake, the exhaust temperature, the EGR (Exhaust Gas Recirculation) gas flow rate, and the like.
（口元温度推定部１１２）
　口元温度推定部１１２は、取得部１１１で取得されたクランクシャフト５５の回転速度および燃料噴射量と、記憶部１２０に記憶された口元温度推定マップと、に基づいて、ピストン４０の口元部４３の温度を推定する。口元温度推定部１１２は、口元温度推定マップ等に基づき推定した温度を、取得部１１１で取得された燃料噴射時期等の情報を用いて補正して、当該補正した値を推定口元部温度として推定する。 (Mouth temperature estimation unit 112)
The mouth temperature estimation unit 112 of the mouth portion 43 of the piston 40 is based on the rotation speed and fuel injection amount of the crankshaft 55 acquired by the acquisition unit 111 and the mouth temperature estimation map stored in the storage unit 120. Estimate the temperature. The mouth temperature estimation unit 112 corrects the temperature estimated based on the mouth temperature estimation map or the like using the information such as the fuel injection timing acquired by the acquisition unit 111, and estimates the corrected value as the estimated mouth temperature. do.
（判定部１１３）
　判定部１１３は、取得部１１１で取得されたエンジン状態情報に基づいて、ピストン４０に向けて冷却用オイルが噴射されているか否かを判定する。 (Determining unit 113)
The determination unit 113 determines whether or not the cooling oil is injected toward the piston 40 based on the engine state information acquired by the acquisition unit 111.
（他部温度推定部１１４）
　他部温度推定部１１４は、判定部１１３で冷却用オイルが噴射されていると判定された場合、記憶部１２０に記憶された第１の推定式（式（１））に、口元温度推定部１１２で推定された推定口元部温度を代入することによって、推定他部温度を求める。他部温度推定部１１４は、判定部１１３で冷却用オイルが噴射されていないと判定された場合、記憶部１２０に記憶された第２の推定式（式（２））に、口元温度推定部１１２で推定された推定口元部温度を代入することによって、推定他部温度を求める。 (Other part temperature estimation part 114)
When the determination unit 113 determines that the cooling oil has been injected, the other unit temperature estimation unit 114 uses the mouth temperature estimation unit to the first estimation formula (formula (1)) stored in the storage unit 120. By substituting the estimated mouth temperature estimated in 112, the estimated temperature of the other part is obtained. When the determination unit 113 determines that the cooling oil has not been injected, the other unit temperature estimation unit 114 uses the mouth temperature estimation unit to the second estimation formula (formula (2)) stored in the storage unit 120. By substituting the estimated mouth temperature estimated in 112, the estimated temperature of the other part is obtained.
　推定他部温度と、実際の他部（ピンボス部５０）の温度とは、エンジン１０の状態によって異なる場合がある。特に、エンジン１０の状態が過渡的に変化する状況では、推定他部温度と実際のピンボス部５０の温度との違いが顕著である。そして、エンジン１０の状態によって、推定他部温度の変化の速さの度合いを示す時定数が変化する。 The estimated temperature of the other part and the actual temperature of the other part (pin boss part 50) may differ depending on the state of the engine 10. In particular, in a situation where the state of the engine 10 changes transiently, the difference between the estimated temperature of the other part and the actual temperature of the pin boss part 50 is remarkable. Then, depending on the state of the engine 10, the time constant indicating the degree of change in the estimated temperature of the other part changes.
　そこで、他部温度推定部１１４は、エンジン１０の状態に対応する時定数を用いて、推定他部温度をさらに補正して、補正他部温度を算出する。 Therefore, the other part temperature estimation unit 114 further corrects the estimated other part temperature by using the time constant corresponding to the state of the engine 10, and calculates the corrected other part temperature.
　他部温度推定部１１４は、記憶部１２０に記憶されている複数の時定数の中から、推定他部温度の変化状況、エンジン１０の運転状態、および、ピストン４０への冷却用オイルの噴射状態に基づいて、所定の時定数を選択する。他部温度推定部１１４は、選択した所定の時定数に基づいて、推定他部温度を補正する。 The other part temperature estimation unit 114 has a change state of the estimated other part temperature, an operating state of the engine 10, and a cooling oil injection state to the piston 40 from among a plurality of time constants stored in the storage unit 120. Select a given time constant based on. The other part temperature estimation unit 114 corrects the estimated other part temperature based on the selected predetermined time constant.
　他部温度推定部１１４は、新たに推定した推定他部温度と、１周期前に推定した推定他部温度との差分値を所定の時定数で除算した値を、１周期前の推定他部温度に加算することにより、推定他部温度を補正する。これにより、推定他部温度を、実際のピンボス部５０の温度の変化の速さに対応するものに補正することができる。 The other part temperature estimation unit 114 divides the difference value between the newly estimated estimated other part temperature and the estimated other part temperature estimated one cycle before by a predetermined time constant, and divides the value by the estimated other part temperature one cycle before. By adding to the temperature, the estimated temperature of other parts is corrected. Thereby, the estimated temperature of the other part can be corrected to correspond to the speed of change in the temperature of the actual pin boss part 50.
　推定他部温度の変化の速度が速い場合には、他部温度推定部１１４は、相対的に小さい時定数を選択する。これにより、補正他部温度は、新たに推定された推定他部温度の影響が大きくなる。 When the rate of change in the estimated temperature of the other part is fast, the temperature estimation part 114 of the other part selects a relatively small time constant. As a result, the corrected other part temperature is greatly affected by the newly estimated estimated other part temperature.
　また、推定他部温度の変化の速度が遅い場合には、他部温度推定部１１４は、相対的に大きい時定数を選択する。これにより、補正他部温度は、過去に推定された推定他部温度の影響が大きくなる。 Further, when the rate of change of the estimated temperature of the other part is slow, the temperature of the other part 114 selects a relatively large time constant. As a result, the corrected other part temperature is greatly affected by the estimated other part temperature estimated in the past.
　他部温度推定部１１４は、例えば以下の式（３）を用いて補正他部温度ＴPSCを算出する。なお、補正他部温度の算出式は式（３）に限定されない。
　　ＴPSC＝ＴPSO＋γ×（ＴPS－ＴPSO）／τ　・・・　（３）
　　　ＴPSO：１周期前に推定された推定他部温度
　　　ＴPS：新たに推定された推定他部温度
　　　γ：所定値
　　　τ：時定数 The other part temperature estimation unit 114 calculates the corrected other part temperature T PSC using, for example, the following equation (3). The formula for calculating the temperature of the corrected other part is not limited to the formula (3).
T PSC = T PSO + γ × ( TPS-T PSO ) / τ ・ ・ ・ (3)
T PSO : Estimated other part temperature estimated before one cycle T PS : Estimated other part temperature newly estimated γ: Predetermined value τ: Time constant
　温度制御部１３０は、ピストン温度推定装置１１０で求められた補正他部温度に基づいて、ピストン４０の長寿命化を図れるように他部の温度を制御する。本第１の実施の形態では、他部の一例であるピンボス部５０の温度を推定する。ピンボス部５０では、耐久性の観点から、硬度低下を招く温度以下に、温度が制御されることが好ましい。ピンボス部５０の硬度が低下すると、ピンボス部５０に亀裂が発生するからである。ピストン４０がアルミニウム合金で構成されている場合、ピンボス部５０の硬度低下を招かないように、一例としてピンボス部５０の温度を２００℃以下に制御する必要がある。温度制御部１３０は、補正他部温度がピストン４０の長寿命化を図れる２００℃を超えないように、以下の降温制御Ａ，Ｂ，Ｃ，Ｄ，Ｅ，Ｆのうち、少なくともいずれか１つの降温制御を行うことによって、ピンボス部５０の温度が２００℃を超えないようにする。 The temperature control unit 130 controls the temperature of the other part based on the corrected temperature of the other part obtained by the piston temperature estimation device 110 so as to extend the life of the piston 40. In the first embodiment, the temperature of the pin boss portion 50, which is an example of the other portion, is estimated. From the viewpoint of durability, it is preferable that the temperature of the pin boss portion 50 is controlled to be equal to or lower than the temperature at which the hardness is lowered. This is because when the hardness of the pin boss portion 50 decreases, cracks occur in the pin boss portion 50. When the piston 40 is made of an aluminum alloy, it is necessary to control the temperature of the pin boss portion 50 to 200 ° C. or lower as an example so as not to cause a decrease in the hardness of the pin boss portion 50. The temperature control unit 130 has at least one of the following temperature reduction controls A, B, C, D, E, and F so that the temperature of the corrected other unit does not exceed 200 ° C., which can extend the life of the piston 40. By controlling the temperature drop, the temperature of the pin boss portion 50 is prevented from exceeding 200 ° C.
　降温制御Ａ：冷却オイルが噴射されていない場合、供給バルブ６２を「開」に制御して、冷却オイルを噴射する
　降温制御Ｂ：冷却オイルが噴射されている場合、可変オイルポンプ６４を制御して、冷却オイルの単位時間当たりの噴射量を増やす
　降温制御Ｃ：燃焼室１１への燃料噴射量を減らす
　降温制御Ｄ：燃焼室１１への燃料噴射タイミグを遅らせる（通常よりもピストン４０の位置が低くなるタイミングで燃料を噴射する）
　降温制御Ｅ：ＥＧＲガス流量を増やす
　降温制御Ｆ：シリンダ２０の冷却水の供給量を増やす Temperature lowering control A: When the cooling oil is not injected, the supply valve 62 is controlled to "open" to inject the cooling oil. Temperature lowering control B: When the cooling oil is injected, the variable oil pump 64 is controlled. Cooling oil injection amount per unit time is increased. Temperature lowering control C: Fuel injection amount to the combustion chamber 11 is reduced. Temperature lowering control D: Fuel injection timing to the combustion chamber 11 is delayed (the position of the piston 40 is higher than usual). Inject fuel at the timing when it becomes low)
Temperature lowering control E: Increase the EGR gas flow rate Lower temperature control F: Increase the supply amount of cooling water in the cylinder 20
　降温制御Ａが行われると、新たに噴射された冷却用オイルによる冷却によって、ピストン４０の温度が下がる。降温制御Ｂが行われると、冷却用オイルによる冷却能力が向上するため、ピストン４０の温度が下がる。降温制御Ｃが行われると、燃焼によりピストン４０に与えられる熱量が減少するため、ピストン４０の温度が下がる。降温制御Ｄが行われると、通常よりも圧力が低い状態で燃料が噴射されるため、燃焼によりピストン４０に与えられる熱量が減少し、ピストン４０の温度が下がる。降温制御Ｅが行われると、ＥＧＲガスがエンジン１０内に戻されて燃焼温度が低下し，燃焼ガスから受熱するピストン４０の温度が下がる。降温制御Ｆが行われると、シリンダ２０の温度が下がり、当該シリンダ２０の温度低下に伴い、ピストン４０の温度が下がる。 When the temperature lowering control A is performed, the temperature of the piston 40 is lowered by cooling with the newly injected cooling oil. When the temperature lowering control B is performed, the cooling capacity of the cooling oil is improved, so that the temperature of the piston 40 is lowered. When the temperature lowering control C is performed, the amount of heat given to the piston 40 by combustion decreases, so that the temperature of the piston 40 drops. When the temperature lowering control D is performed, the fuel is injected in a state where the pressure is lower than usual, so that the amount of heat given to the piston 40 by combustion decreases, and the temperature of the piston 40 drops. When the temperature lowering control E is performed, the EGR gas is returned to the engine 10 to lower the combustion temperature, and the temperature of the piston 40 that receives heat from the combustion gas is lowered. When the temperature lowering control F is performed, the temperature of the cylinder 20 is lowered, and the temperature of the piston 40 is lowered as the temperature of the cylinder 20 is lowered.
〔ピストン温度制御装置の動作〕
　次に、ピストン温度制御装置１００の動作について説明する。図４は、ピストン温度制御装置の動作の一例を示すフローチャートである。 [Operation of piston temperature control device]
Next, the operation of the piston temperature control device 100 will be described. FIG. 4 is a flowchart showing an example of the operation of the piston temperature control device.
　まず、図４に示すように、ピストン温度制御装置１００の取得部１１１は、エンジン状態情報を取得する（ステップＳ１）。 First, as shown in FIG. 4, the acquisition unit 111 of the piston temperature control device 100 acquires engine state information (step S1).
　次に、ピストン温度制御装置１００の口元温度推定部１１２は、取得部１１１で取得されたエンジン状態情報に含まれるクランクシャフト５５の回転速度および燃料噴射量と、記憶部１２０に記憶された口元温度推定マップと、等に基づいて、推定口元部温度を推定する（ステップＳ２）。 Next, the mouth temperature estimation unit 112 of the piston temperature control device 100 includes the rotation speed and fuel injection amount of the crankshaft 55 included in the engine state information acquired by the acquisition unit 111, and the mouth temperature stored in the storage unit 120. The estimated mouth temperature is estimated based on the estimation map and the like (step S2).
　次に、ピストン温度制御装置１００の判定部１１３は、取得部１１１で取得されたエンジン状態情報に含まれる冷却用オイルの噴射の有無に関する情報に基づいて、冷却用オイルが噴射されているか否かを判定する（ステップＳ３）。 Next, the determination unit 113 of the piston temperature control device 100 determines whether or not the cooling oil is injected based on the information regarding the presence or absence of the injection of the cooling oil included in the engine state information acquired by the acquisition unit 111. Is determined (step S3).
　判定部１１３で冷却用オイルが噴射されていると判定された場合（ステップＳ３：ＹＥＳ）、ピストン温度制御装置１００の他部温度推定部１１４は、記憶部１２０に記憶された第１の推定式（式（１））と、推定口元部温度と、に基づいて、推定他部温度を推定する（ステップＳ４）。 When it is determined by the determination unit 113 that the cooling oil has been injected (step S3: YES), the other unit temperature estimation unit 114 of the piston temperature control device 100 has the first estimation formula stored in the storage unit 120. The estimated temperature of the other part is estimated based on (Equation (1)) and the estimated temperature of the mouth part (step S4).
　一方、判定部１１３で冷却用オイルが噴射されていないと判定された場合（ステップＳ３：ＮＯ）、他部温度推定部１１４は、記憶部１２０に記憶された第２の推定式（式（２））と、推定口元部温度と、に基づいて、推定他部温度を推定する（ステップＳ５）。 On the other hand, when the determination unit 113 determines that the cooling oil has not been injected (step S3: NO), the other unit temperature estimation unit 114 has a second estimation formula (formula (2)) stored in the storage unit 120. )) And the estimated mouth temperature, and the estimated temperature of the other part is estimated (step S5).
　ステップＳ４またはステップＳ５の処理の後、他部温度推定部１１４は、取得部１１１で取得されたエンジン状態情報に含まれるエンジン１０の運転状態および冷却用オイルの噴射状態と、推定他部温度の変化状況と、に基づいて、時定数を選択する（ステップＳ６）。 After the processing of step S4 or step S5, the other part temperature estimation unit 114 determines the operating state of the engine 10 and the injection state of the cooling oil included in the engine state information acquired by the acquisition unit 111, and the estimated other part temperature. A time constant is selected based on the change situation (step S6).
　次に、他部温度推定部１１４は、算出式（式（３））と、ステップＳ４またはステップＳ５で推定された推定他部温度と、ステップＳ６で選択した時定数と、に基づいて、補正他部温度を算出する（ステップＳ７）。なお、１周期目のピストン温度制御処理を行う場合、式（３）の１周期前に推定された推定他部温度ＴPSOが存在しない。この場合、オイル温度あるいは別途計算して求めた推定口元部温度や、予め設定された値を推定他部温度ＴPSOとして用いても良い。 Next, the other part temperature estimation unit 114 corrects based on the calculation formula (formula (3)), the estimated other part temperature estimated in step S4 or step S5, and the time constant selected in step S6. The temperature of the other part is calculated (step S7). When the piston temperature control process in the first cycle is performed, the estimated other temperature T PSO estimated one cycle before the equation (3) does not exist. In this case, the oil temperature, the estimated mouth temperature calculated separately, or a preset value may be used as the estimated other temperature T PSO .
　次に、ピストン温度制御装置１００の温度制御部１３０は、補正他部温度が閾値を超えているか否かを判定する（ステップＳ８）。ステップＳ８で用いる閾値は、当該閾値を超えている状態のまま降温制御を行わない場合、他部の温度が上昇して、他部に不具合が発生するおそれがあるような温度に設定されている。例えば、本第１の実施の形態では、閾値は、当該閾値を超えている状態のまま降温制御を行わない場合、ピンボス部５０の温度が上昇して２００℃を超えるおそれがあるような温度に設定されている。なお、ピンボス部５０の閾値を２００℃に設定しても良い。ピンボス部５０の温度が２００℃を超えている時間が長くなければ、ピンボス部５０に亀裂が発生するおそれが少なくなるからである。 Next, the temperature control unit 130 of the piston temperature control device 100 determines whether or not the temperature of the corrected other unit exceeds the threshold value (step S8). The threshold value used in step S8 is set to a temperature at which the temperature of the other part may rise and a problem may occur in the other part if the temperature lowering control is not performed while the threshold value is exceeded. .. For example, in the first embodiment, the threshold value is set to a temperature at which the temperature of the pin boss portion 50 may rise and exceed 200 ° C. if the temperature lowering control is not performed while the threshold value is exceeded. It is set. The threshold value of the pin boss portion 50 may be set to 200 ° C. This is because if the temperature of the pin boss portion 50 does not exceed 200 ° C. for a long time, the possibility of cracks in the pin boss portion 50 is reduced.
　温度制御部１３０は、補正他部温度が閾値を超えていると判定した場合（ステップＳ８：ＹＥＳ）、降温制御Ａ～Ｆのうち少なくとも１つの降温制御を行う（ステップＳ９）。 When the temperature control unit 130 determines that the temperature of the corrected other unit exceeds the threshold value (step S8: YES), the temperature control unit 130 performs temperature decrease control of at least one of the temperature decrease controls A to F (step S9).
　ステップＳ９の処理の後、または、補正他部温度が閾値を超えていないと判定した場合（ステップＳ８：ＮＯ）、温度制御部１３０は、ピストン温度制御処理を終了させるか否かを判定する（ステップＳ１０）。 After the processing of step S9, or when it is determined that the temperature of the corrected other part does not exceed the threshold value (step S8: NO), the temperature control unit 130 determines whether or not to terminate the piston temperature control processing (step S8: NO). Step S10).
　温度制御部１３０は、例えば、エンジン１０の運転が終了した場合等、ピストン温度制御処理を終了させると判定した場合（ステップＳ１０：ＹＥＳ）、処理を終了させる。一方、温度制御部１３０でピストン温度制御処理を終了させないと判定した場合（ステップＳ１０：ＮＯ）、ピストン温度制御装置１００は、ステップＳ１の処理を行う。 When the temperature control unit 130 determines that the piston temperature control process is to be terminated, for example, when the operation of the engine 10 is completed (step S10: YES), the temperature control unit 130 terminates the process. On the other hand, when the temperature control unit 130 determines that the piston temperature control process is not terminated (step S10: NO), the piston temperature control device 100 performs the process of step S1.
〔第１の実施の形態の作用効果〕
　ピストン温度制御装置１００のピストン温度推定装置１１０は、ピストン４０のキャビティ４２の口元部４３の推定口元部温度を推定し、当該推定口元部温度と、温度推定用情報と、に基づいて、推定他部温度を推定する。このため、適切に推定された推定他部温度に基づいて、他部の温度を制御することによって、ピストン４０の長寿命化を図ることができる。特に、他部の一例であるピンボス部５０の温度を推定し、ピンボス部５０の温度が２００℃を超えないようにするための降温制御を行うため、ピンボス部５０における亀裂の発生を抑制することができる。 [Action and effect of the first embodiment]
The piston temperature estimation device 110 of the piston temperature control device 100 estimates the estimated mouth temperature of the mouth 43 of the cavity 42 of the piston 40, and estimates and others based on the estimated mouth temperature and the temperature estimation information. Estimate the temperature of the part. Therefore, the life of the piston 40 can be extended by controlling the temperature of the other part based on the estimated temperature of the other part. In particular, in order to estimate the temperature of the pin boss portion 50, which is an example of another portion, and to control the temperature decrease so that the temperature of the pin boss portion 50 does not exceed 200 ° C., the occurrence of cracks in the pin boss portion 50 is suppressed. Can be done.
　ピストン温度推定装置１１０は、冷却用オイルが噴射されているか否かに応じて、異なる推定式を用いて、推定他部温度を推定する。このため、冷却用オイルによってピストン４０が冷却されているか否かに応じて、推定他部温度をより適切に推定することができる。 The piston temperature estimation device 110 estimates the estimated temperature of the other part using different estimation formulas depending on whether or not the cooling oil is injected. Therefore, the estimated temperature of the other part can be estimated more appropriately depending on whether or not the piston 40 is cooled by the cooling oil.
　ピストン温度推定装置１１０は、推定他部温度を他部の温度の変化速度の度合いを示す時定数に基づいて補正した、補正他部温度を算出する。このため、推定時点での他部の温度を、より適切に推定することができる。 The piston temperature estimation device 110 calculates the corrected other part temperature obtained by correcting the estimated other part temperature based on the time constant indicating the degree of change rate of the temperature of the other part. Therefore, the temperature of the other part at the time of estimation can be estimated more appropriately.
　ピストン温度推定装置１１０は、他部の温度の変化状況、クランクシャフト５５の回転速度、燃料噴射量および冷却用オイルの噴射状態に基づいて、複数の時定数の中から選択された所定の時定数を用いて、補正他部温度を算出する。このため、実際の他部の温度を精度良く推定することができる。 The piston temperature estimation device 110 has a predetermined time constant selected from a plurality of time constants based on the temperature change state of other parts, the rotation speed of the crankshaft 55, the fuel injection amount, and the injection state of the cooling oil. Is used to calculate the corrected temperature of the other part. Therefore, the actual temperature of other parts can be estimated accurately.
［第２の実施の形態］
　次に、本開示の第２の実施の形態について説明する。第２の実施の形態は、他部の一例としてクーリングチャンネル４４の温度を推定する点で、第１の実施の形態と相違する。以下、相違点を中心に説明する。なお、ピストン温度制御装置１００の動作は、第１の実施の形態と同様なので、説明を省略する。 [Second Embodiment]
Next, a second embodiment of the present disclosure will be described. The second embodiment differs from the first embodiment in that the temperature of the cooling channel 44 is estimated as an example of the other part. Hereinafter, the differences will be mainly described. Since the operation of the piston temperature control device 100 is the same as that of the first embodiment, the description thereof will be omitted.
〔エンジンの概略構成〕
　第２の実施の形態のピストン４０は、スチールや鋳鉄で構成されている点で、第１の実施の形態のピストン４０と相違する。 [Outline configuration of engine]
The piston 40 of the second embodiment is different from the piston 40 of the first embodiment in that it is made of steel or cast iron.
〔ピストン温度制御装置の構成〕
　記憶部１２０は、上記式（１）で表される第１の推定式と、上記式（２）で表される第２の推定式と、を記憶する。第２の実施の形態の係数αON，αOFF，βON，βOFFは、第１の実施の形態の値とは異なっている。クーリングチャンネル４４は、ピンボス部５０よりも口元部４３に近い。このため、クーリングチャンネル４４の係数αON，αOFFは、ピンボス部５０の係数αON，αOFFよりも大きい値である。第１の推定式および第２の推定式は、第１の実施の形態の第１の推定式および第２の推定式と同様に、冷却用オイルが噴射されている状態および冷却用オイルが噴射されていない状態における、口元部４３の温度と、クーリングチャンネル４４の温度との関係に基づいて求めることができる。 [Structure of piston temperature control device]
The storage unit 120 stores the first estimation formula represented by the above formula (1) and the second estimation formula represented by the above formula (2). The coefficients α ON , α OFF , β ON , β OFF of the second embodiment are different from the values of the first embodiment. The cooling channel 44 is closer to the mouth portion 43 than the pin boss portion 50. Therefore, the coefficients α ON and α OFF of the cooling channel 44 are larger than the coefficients α ON and α OFF of the pin boss portion 50. The first estimation formula and the second estimation formula are the same as the first estimation formula and the second estimation formula of the first embodiment, in a state where the cooling oil is injected and the cooling oil is injected. It can be obtained based on the relationship between the temperature of the mouth portion 43 and the temperature of the cooling channel 44 in the non-exposed state.
　記憶部１２０は、第１～第８の時定数を記憶する。本第２の実施の形態では、第１～第８の時定数は、クーリングチャンネル４４の温度の変化速度の度合いを示す。このため、第２の実施の形態の第１～第８の時定数は、第１の実施の形態の値とは異なっている。 The storage unit 120 stores the first to eighth time constants. In the second embodiment, the first to eighth time constants indicate the degree of change rate of the temperature of the cooling channel 44. Therefore, the first to eighth time constants of the second embodiment are different from the values of the first embodiment.
　他部温度推定部１１４は、記憶部１２０に記憶された第１，第２の推定式と、推定口元部温度と、に基づいて、クーリングチャンネル４４の温度を、推定他部温度として推定する。例えば、他部温度推定部１１４は、クーリングチャンネル４４の内壁の一部の温度を推定する。 The other part temperature estimation unit 114 estimates the temperature of the cooling channel 44 as the estimated other part temperature based on the first and second estimation formulas stored in the storage unit 120 and the estimated mouth portion temperature. For example, the other part temperature estimation unit 114 estimates the temperature of a part of the inner wall of the cooling channel 44.
　温度制御部１３０は、ピストン４０の長寿命化を図れるように、クーリングチャンネル４４の温度を制御する。クーリングチャンネル４４では、冷却用オイルが炭化して固着が進行する温度以下に、温度が制御されることが好ましい。クーリングチャンネル４４における冷却用オイルの炭化成分の固着量が多くなると、クーリングチャンネル４４の内面における伝熱量の低下を招くとともに、循環できる冷却用オイルの量が減ってしまい、ピストン４０の冷却効率が下がるからである。ピストン４０がスチールで構成されている場合、冷却用オイルが炭化して固着が進行しないように、一例としてクーリングチャンネル４４の温度を３００℃以下に制御する必要がある。このため、図４のステップＳ８で用いる閾値は、当該閾値を超えている状態のまま降温制御を行わない場合、クーリングチャンネル４４の温度が上昇して３００℃を超えるおそれがあるような温度に設定されている。温度制御部１３０は、ステップＳ８において、補正他部温度が閾値を超える場合、上述の降温制御Ａ，Ｂ，Ｃ，Ｄ，Ｅ，Ｆのうち、少なくともいずれか１つの降温制御を行うことによって、クーリングチャンネル４４の温度が３００℃を超えないようにする。なお、クーリングチャンネル４４の閾値を３００℃に設定しても良い。クーリングチャンネル４４の温度が３００℃を超えている時間が長くなければ、クーリングチャンネル４４における冷却用オイルの固着が進行するおそれが少なくなるからである。 The temperature control unit 130 controls the temperature of the cooling channel 44 so that the life of the piston 40 can be extended. In the cooling channel 44, it is preferable that the temperature is controlled to be equal to or lower than the temperature at which the cooling oil is carbonized and the fixing proceeds. If the amount of carbonized component of the cooling oil fixed in the cooling channel 44 increases, the amount of heat transfer on the inner surface of the cooling channel 44 decreases, the amount of cooling oil that can be circulated decreases, and the cooling efficiency of the piston 40 decreases. Because. When the piston 40 is made of steel, it is necessary to control the temperature of the cooling channel 44 to 300 ° C. or lower as an example so that the cooling oil does not carbonize and the fixing does not proceed. Therefore, the threshold value used in step S8 of FIG. 4 is set to a temperature at which the temperature of the cooling channel 44 may rise and exceed 300 ° C. if the temperature lowering control is not performed while the threshold value is exceeded. Has been done. In step S8, when the temperature of the corrected other unit exceeds the threshold value, the temperature control unit 130 controls the temperature decrease of at least one of the above-mentioned temperature decrease controls A, B, C, D, E, and F. The temperature of the cooling channel 44 should not exceed 300 ° C. The threshold value of the cooling channel 44 may be set to 300 ° C. This is because if the temperature of the cooling channel 44 does not exceed 300 ° C. for a long time, there is less possibility that the cooling oil will adhere to the cooling channel 44.
〔第２の実施の形態の作用効果〕
　ピストン温度制御装置１００のピストン温度推定装置１１０は、ピストン４０のキャビティ４２の口元部４３の推定口元部温度を推定し、当該推定口元部温度と、温度推定用情報と、に基づいて、クーリングチャンネル４４の温度を推定する。このため、適切に推定されたクーリングチャンネル４４の温度に基づいて、クーリングチャンネル４４の温度を制御することによって、クーリングチャンネル４４における冷却用オイルの炭化成分の固着量が多くなることを抑制することができる。その結果、ピストン４０の長寿命化を図ることができる。 [Action and effect of the second embodiment]
The piston temperature estimation device 110 of the piston temperature control device 100 estimates the estimated mouth temperature of the mouth 43 of the cavity 42 of the piston 40, and based on the estimated mouth temperature and the temperature estimation information, the cooling channel. Estimate the temperature of 44. Therefore, by controlling the temperature of the cooling channel 44 based on the appropriately estimated temperature of the cooling channel 44, it is possible to suppress an increase in the amount of the carbonized component of the cooling oil adhered to the cooling channel 44. can. As a result, the life of the piston 40 can be extended.
［実施の形態の変形例］
　本開示は、これまでに説明した実施の形態に示されたものに限られないことは言うまでも無く、その趣旨を逸脱しない範囲内で、種々の変形を加えることができる。 [Modified example of the embodiment]
Needless to say, the present disclosure is not limited to those shown in the embodiments described above, and various modifications can be made without departing from the spirit of the present disclosure.
　例えば、ピストン温度推定装置１１０で温度を推定する他部としては、ピンボス部５０およびクーリングチャンネル４４以外の部位であっても良い。例えば、他部は、リング溝４７であっても良い。ピストン４０がアルミニウム合金で構成され、ピストンリング４８がスチールや鋳鉄で構成されている場合、リング溝４７では、ピストンリング４８が凝着する温度以下に、温度が制御されることが好ましい。ピストンリング４８がリング溝４７に凝着すると、リングの機能を失い、ブローバイガスの流量および、ピストンリング４８とシリンダ２０との接触面の摺動抵抗の悪化を招く。このため、図４のステップＳ８で用いる閾値は、当該閾値を超えている状態のまま降温制御を行わない場合、リング溝４７の温度が上昇して、ピストンリング４８がリング溝４７に凝着する温度を超えるおそれがあるような温度に設定されている。温度制御部１３０は、ステップＳ８において、補正他部温度が閾値を超える場合、上述の降温制御Ａ，Ｂ，Ｃ，Ｄ，Ｅのうち、少なくともいずれか１つの降温制御を行うことによって、ピストンリング４８がリング溝４７に凝着しないようにすれば良い。また、ピストン温度推定装置１１０で温度を推定する他部としては、キャビティ４２を構成する口元部４３以外の部分、すなわちキャビティ４２の側面部４２Ａ、底面部４２Ｂであっても良いし、ピストン上部４１の側面部４１Ａ（ピストン４０におけるリング溝４７よりキャビティ４２側の側面部）であっても良い。なお、第１，第２の推定式の係数αON，αOFF，βON，βOFFおよび第１～第８の時定数は、リング溝４７、キャビティ４２の側面部４２Ａ、底面部４２Ｂおよびピストン上部４１の側面部４１Ａの温度変化特性に応じて、適切に設定されれば良い。 For example, the portion other than the pin boss portion 50 and the cooling channel 44 may be used as a portion for estimating the temperature by the piston temperature estimation device 110. For example, the other portion may be a ring groove 47. When the piston 40 is made of an aluminum alloy and the piston ring 48 is made of steel or cast iron, it is preferable that the temperature of the ring groove 47 is controlled to be equal to or lower than the temperature at which the piston ring 48 adheres. When the piston ring 48 adheres to the ring groove 47, the function of the ring is lost, which causes deterioration of the flow rate of blow-by gas and the sliding resistance of the contact surface between the piston ring 48 and the cylinder 20. Therefore, if the threshold value used in step S8 of FIG. 4 is not controlled to lower the temperature while exceeding the threshold value, the temperature of the ring groove 47 rises and the piston ring 48 adheres to the ring groove 47. The temperature is set so that it may exceed the temperature. In step S8, when the temperature of the corrected other unit exceeds the threshold value, the temperature control unit 130 controls the temperature decrease of at least one of the above-mentioned temperature decrease controls A, B, C, D, and E, thereby performing the piston ring. It suffices to prevent 48 from sticking to the ring groove 47. Further, as the other portion for estimating the temperature by the piston temperature estimation device 110, a portion other than the mouth portion 43 constituting the cavity 42, that is, the side surface portion 42A and the bottom surface portion 42B of the cavity 42 may be used, or the piston upper portion 41 may be used. The side surface portion 41A (the side surface portion on the cavity 42 side of the ring groove 47 in the piston 40) may be used. The coefficients α ON , α OFF , β ON , β OFF and the first to eighth time constants of the first and second estimation formulas are the ring groove 47, the side surface portion 42A of the cavity 42, the bottom surface portion 42B, and the piston. It may be appropriately set according to the temperature change characteristic of the side surface portion 41A of the upper portion 41.
　他部温度推定部１１４は、冷却用オイルが噴射されているか否かに関係なく、同じ推定式を用いて、推定他部温度を推定しても良い。この場合、例えば、図３に示す、冷却用オイルが噴射されているとき、および、冷却用オイルが噴射されていないときの全てのデータの一次近似式を推定式として求め、この推定式に推定口元部温度を代入すれば良い。 The other part temperature estimation unit 114 may estimate the estimated other part temperature using the same estimation formula regardless of whether or not the cooling oil is injected. In this case, for example, the linear approximation formulas of all the data when the cooling oil is injected and when the cooling oil is not injected, which are shown in FIG. 3, are obtained as estimation formulas and estimated by this estimation formula. Substitute the mouth temperature.
　第１～第８の時定数を使い分ける構成としたが、これに限定されない。例えば、他部の温度の変化状況、エンジン運転状態および冷却用オイルの噴射状態に基づいて、時定数をさらに細分化しても良い。時定数の細分化にあたり、その他のパラメータを考慮しても良い。 The first to eighth time constants were used properly, but it is not limited to this. For example, the time constant may be further subdivided based on the temperature change state of other parts, the engine operating state, and the injection state of the cooling oil. Other parameters may be taken into consideration when subdividing the time constant.
　他部温度推定部１１４に推定他部温度を補正する機能を設けずに、推定他部温度が閾値を超えるか否かに基づいて、降温制御を行うようにしてもよい。 The temperature drop control may be performed based on whether or not the estimated temperature of the other part exceeds the threshold value without providing the function of correcting the estimated temperature of the other part in the other part temperature estimation unit 114.
　供給バルブ６２としては、温度制御部１３０の制御により能動的に動作する構成に限らず、例えば、弁とばねとを備え、油圧によって開閉するバルブを適用し、油路６５を流れるオイルの油圧が高くなったときに、受動的にバルブが「開」になって、ノズル６３から冷却用オイルを噴射するようにしても良い。また、可変オイルポンプ６４の代わりに、オイルの流量を変化させることができないオイルポンプを用いても良いが、この場合、降温制御Ｂを行うことができなくなる。 The supply valve 62 is not limited to a configuration that actively operates under the control of the temperature control unit 130. For example, a valve provided with a valve and a spring and opened and closed by hydraulic pressure is applied, and the hydraulic pressure of the oil flowing through the oil passage 65 is applied. When it becomes high, the valve may be passively "opened" to inject cooling oil from the nozzle 63. Further, instead of the variable oil pump 64, an oil pump that cannot change the flow rate of oil may be used, but in this case, the temperature lowering control B cannot be performed.
　２０２０年９月２４日出願の特願２０２０－１６００６１の日本出願に含まれる明細書、図面および要約書の開示内容は、すべて本願に援用される。 All disclosures of the specification, drawings and abstract contained in the Japanese application of Japanese Patent Application No. 2020-160061 filed on September 24, 2020 are incorporated herein by reference.
　本開示の構成は、ピストン温度推定装置、ピストン温度制御装置、ピストン温度推定方法およびピストン温度制御方法に適用することができる。 The configuration of the present disclosure can be applied to a piston temperature estimation device, a piston temperature control device, a piston temperature estimation method, and a piston temperature control method.
　１０　エンジン
　１１　燃焼室
　２０　シリンダ
　２１　冷却通路
　２２　ライナ
　２３　シリンダヘッド
　２４　インジェクタ
　２５　吸気ポート
　２６　排気ポート
　２７　吸気用バルブ
　２８　排気用バルブ
　４０　ピストン
　４１　ピストン上部
　４１Ａ　側面部
　４２　キャビティ
　４２Ａ　側面部
　４２Ｂ　底面部
　４３　口元部
　４４　クーリングチャンネル
　４５　導入孔
　４６　排出孔
　４７　リング溝
　４８　ピストンリング
　４９　スカート部
　５０　ピンボス部
　５１　ピン嵌入孔
　５２　ピストンピン
　５３　コンロッド
　５４　クランクピン
　５５　クランクシャフト
　６１　オイルジェット
　６２　供給バルブ
　６３　ノズル
　６４　可変オイルポンプ
　６５　油路
　１００　ピストン温度制御装置
　１１０　ピストン温度推定装置
　１１１　取得部
　１１２　口元温度推定部
　１１３　判定部
　１１４　他部温度推定部
　１２０　記憶部
　１３０　温度制御部 10 Engine 11 Combustion chamber 20 Cylinder 21 Cooling passage 22 Liner 23 Cylinder head 24 Injector 25 Intake port 26 Exhaust port 27 Intake valve 28 Exhaust valve 40 Piston 41 Piston top 41A Side part 42 Cavity 42A Side part 42B Bottom part 43 Mouth part 44 Cooling channel 45 Introduction hole 46 Discharge hole 47 Ring groove 48 Piston ring 49 Skirt part 50 Pin boss part 51 Pin fitting hole 52 Piston pin 53 Conrod 54 Crank pin 55 Crank shaft 61 Oil jet 62 Supply valve 63 Nozzle 64 Variable oil pump 65 Oil Road 100 Piston temperature control device 110 Piston temperature estimation device 111 Acquisition unit 112 Mouth temperature estimation unit 113 Judgment unit 114 Other unit Temperature estimation unit 120 Storage unit 130 Temperature control unit

Claims (12)

  1. 　内燃機関を構成するピストンのキャビティの口元部の温度を推定する口元温度推定部と、
    　前記口元温度推定部で推定された前記口元部の温度に基づいて、前記ピストンにおける前記口元部以外の他部の温度を推定する他部温度推定部と、を備える、ピストン温度推定装置。     A mouth temperature estimation unit that estimates the temperature of the mouth portion of the cavity of the piston that constitutes the internal combustion engine, and a mouth temperature estimation unit.
    A piston temperature estimation device including a other part temperature estimation unit that estimates the temperature of a portion other than the mouth portion of the piston based on the temperature of the mouth portion estimated by the mouth temperature estimation unit.
  2. 　前記他部温度推定部は、前記他部の温度および前記口元部の温度の関係を示す温度推定用情報と、前記口元温度推定部で推定された前記口元部の温度と、に基づいて、前記他部の温度を推定する、請求項１に記載のピストン温度推定装置。 The other part temperature estimation unit is based on temperature estimation information indicating the relationship between the temperature of the other part and the temperature of the mouth portion and the temperature of the mouth portion estimated by the mouth temperature estimation unit. The piston temperature estimation device according to claim 1, which estimates the temperature of another part.
  3. 　オイルジェットが前記ピストンに向けてオイルを噴射しているか否かを判定する判定部をさらに備え、
    　前記温度推定用情報は、
    　前記オイルジェットがオイルを噴射している場合における前記他部の温度の推定に用いる第１の推定情報と、
    　オイルを噴射していない場合における前記他部の温度の推定に用いる第２の推定情報と、を備え、
    　前記他部温度推定部は、
    　前記判定部で前記オイルジェットがオイルを噴射していると判定された場合、前記第１の推定情報と、前記口元温度推定部で推定された前記口元部の温度と、に基づいて、前記他部の温度を推定し、
    　前記判定部で前記オイルジェットがオイルを噴射していないと判定された場合、前記第２の推定情報と、前記口元温度推定部で推定された前記口元部の温度と、に基づいて、前記他部の温度を推定する、請求項２に記載のピストン温度推定装置。     Further provided with a determination unit for determining whether or not the oil jet is injecting oil toward the piston.
    The temperature estimation information is
    The first estimation information used for estimating the temperature of the other part when the oil jet is injecting oil, and
    The second estimation information used for estimating the temperature of the other part when the oil is not injected is provided.
    The other part temperature estimation part is
    When it is determined by the determination unit that the oil jet is injecting oil, the other is based on the first estimation information and the temperature of the mouth portion estimated by the mouth temperature estimation unit. Estimate the temperature of the part,
    When it is determined by the determination unit that the oil jet is not injecting oil, the other is based on the second estimation information and the temperature of the mouth portion estimated by the mouth temperature estimation unit. The piston temperature estimation device according to claim 2, which estimates the temperature of the unit.
  4. 　前記他部温度推定部は、前記推定した前記他部の温度を、前記他部の温度の変化速度の度合いを示す時定数に基づいて補正する、請求項１に記載のピストン温度推定装置。 The piston temperature estimation device according to claim 1, wherein the other part temperature estimation unit corrects the estimated temperature of the other part based on a time constant indicating the degree of change rate of the temperature of the other part.
  5. 　前記他部は、ピンボス部、クーリングチャンネル、および、ピストンリングが装着されるリング溝、前記キャビティの側面部、前記キャビティの底面部および前記ピストンにおける前記リング溝より前記キャビティ側の側面部のうち少なくともいずれか１つである、請求項１に記載のピストン温度推定装置。 The other portion is at least one of a pin boss portion, a cooling channel, a ring groove to which a piston ring is mounted, a side surface portion of the cavity, a bottom surface portion of the cavity, and a side surface portion of the piston on the cavity side of the ring groove. The piston temperature estimation device according to claim 1, which is any one of them.
  6. 　請求項１に記載のピストン温度推定装置と、
    　前記ピストン温度推定装置の処理で得られた前記他部の温度に基づいて、前記他部の温度を制御する温度制御部と、を備える、ピストン温度制御装置。     The piston temperature estimation device according to claim 1 and
    A piston temperature control device including a temperature control unit that controls the temperature of the other unit based on the temperature of the other unit obtained in the process of the piston temperature estimation device.
  7. 　前記他部は、ピンボス部であり、
    　前記温度制御部は、前記ピストン温度推定装置の処理で得られた前記ピンボス部の温度に基づいて、前記ピンボス部の温度が、前記ピンボス部の硬度が所定値になる温度を超えないようにするための降温制御を行う、請求項６に記載のピストン温度制御装置。     The other part is a pin boss part.
    The temperature control unit prevents the temperature of the pin boss portion from exceeding a temperature at which the hardness of the pin boss portion reaches a predetermined value, based on the temperature of the pin boss portion obtained by the processing of the piston temperature estimation device. The piston temperature control device according to claim 6, which controls the temperature drop for the purpose.
  8. 　前記他部は、クーリングチャンネルであり、
    　前記温度制御部は、前記ピストン温度推定装置の処理で得られた前記クーリングチャンネルの温度に基づいて、前記クーリングチャンネルの温度が、前記クーリングチャンネル内のオイルが炭化して固化する温度を超えないようにするための降温制御を行う、請求項６に記載のピストン温度制御装置。     The other part is a cooling channel.
    The temperature control unit is based on the temperature of the cooling channel obtained by the processing of the piston temperature estimation device so that the temperature of the cooling channel does not exceed the temperature at which the oil in the cooling channel is carbonized and solidified. The piston temperature control device according to claim 6, wherein the temperature lowering control is performed to control the temperature.
  9. 　前記他部は、ピストンリングが装着されるリング溝であり、
    　前記温度制御部は、前記ピストン温度推定装置の処理で得られた前記リング溝の温度に基づいて、前記リング溝の温度が、前記ピストンリングと前記リング溝とが凝着あるいは前記ピストンリングと前記ピストンを収納するシリンダとの接触面が摩耗する温度を超えないようにするための降温制御を行う、請求項６に記載のピストン温度制御装置。     The other part is a ring groove to which the piston ring is mounted.
    In the temperature control unit, based on the temperature of the ring groove obtained by the processing of the piston temperature estimation device, the temperature of the ring groove is such that the piston ring and the ring groove adhere to each other or the piston ring and the said. The piston temperature control device according to claim 6, wherein the temperature lowering control is performed so that the contact surface with the cylinder for accommodating the piston does not exceed the wear temperature.
  10. 　前記温度制御部は、前記他部の温度を制御するために、オイルジェットから前記ピストンに向けて噴射されるオイルの噴射状態、前記内燃機関の燃焼状態および前記ピストンを収納するシリンダを冷却する冷却水の供給状態のうち、少なくともいずれか１つを制御する、請求項６から９のいずれか一項に記載のピストン温度制御装置。 The temperature control unit cools the injection state of the oil injected from the oil jet toward the piston, the combustion state of the internal combustion engine, and the cylinder accommodating the piston in order to control the temperature of the other unit. The piston temperature control device according to any one of claims 6 to 9, which controls at least one of the water supply states.
  11. 　内燃機関を構成するピストンのキャビティの口元部の温度を推定するステップと、
    　前記推定された前記口元部の温度に基づいて、前記ピストンにおける前記口元部以外の他部の温度を推定するステップと、を実行する、ピストン温度推定方法。     The step of estimating the temperature of the mouth of the cavity of the piston that constitutes the internal combustion engine, and
    A piston temperature estimation method for performing a step of estimating the temperature of a portion other than the mouth portion of the piston based on the estimated temperature of the mouth portion.
  12. 　請求項１１に記載のピストン温度推定方法を実行するステップと、
    　前記ピストン温度推定方法の実行で得られた前記他部の温度に基づいて、前記他部の温度を制御するステップと、を実行する、ピストン温度制御方法。     The step of executing the piston temperature estimation method according to claim 11 and
    A piston temperature control method for executing a step of controlling the temperature of the other part based on the temperature of the other part obtained by executing the piston temperature estimation method.
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JP2005016475A (en) * 2003-06-27 2005-01-20 Nissan Motor Co Ltd Valve clearance amount estimation device for internal combustion engine
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JPH09292288A (en) * 1996-04-26 1997-11-11 Nippon Soken Inc Piston temperature measuring device for internal combustion engine
JP2005016475A (en) * 2003-06-27 2005-01-20 Nissan Motor Co Ltd Valve clearance amount estimation device for internal combustion engine
JP2014202181A (en) * 2013-04-09 2014-10-27 トヨタ自動車株式会社 Internal combustion in-cylinder temperature estimation device, heat generation rate waveform creation device and combustion state diagnosis device
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