WO2011114508A1 - 内燃機関の制御装置 - Google Patents
内燃機関の制御装置 Download PDFInfo
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- WO2011114508A1 WO2011114508A1 PCT/JP2010/054800 JP2010054800W WO2011114508A1 WO 2011114508 A1 WO2011114508 A1 WO 2011114508A1 JP 2010054800 W JP2010054800 W JP 2010054800W WO 2011114508 A1 WO2011114508 A1 WO 2011114508A1
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- fuel
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- switching
- fuel ratio
- ecu
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/0025—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D41/0027—Controlling engines characterised by use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures the fuel being gaseous
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/0602—Control of components of the fuel supply system
- F02D19/0613—Switch-over from one fuel to another
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/0602—Control of components of the fuel supply system
- F02D19/0613—Switch-over from one fuel to another
- F02D19/0615—Switch-over from one fuel to another being initiated by automatic means, e.g. based on engine or vehicle operating conditions
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/0639—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels
- F02D19/0642—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions
- F02D19/0647—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed characterised by the type of fuels at least one fuel being gaseous, the other fuels being gaseous or liquid at standard conditions the gaseous fuel being liquefied petroleum gas [LPG], liquefied natural gas [LNG], compressed natural gas [CNG] or dimethyl ether [DME]
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/30—Controlling fuel injection
- F02D41/3011—Controlling fuel injection according to or using specific or several modes of combustion
- F02D41/3064—Controlling fuel injection according to or using specific or several modes of combustion with special control during transition between modes
- F02D41/307—Controlling fuel injection according to or using specific or several modes of combustion with special control during transition between modes to avoid torque shocks
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D19/00—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures
- F02D19/06—Controlling engines characterised by their use of non-liquid fuels, pluralities of fuels, or non-fuel substances added to the combustible mixtures peculiar to engines working with pluralities of fuels, e.g. alternatively with light and heavy fuel oil, other than engines indifferent to the fuel consumed
- F02D19/0663—Details on the fuel supply system, e.g. tanks, valves, pipes, pumps, rails, injectors or mixers
- F02D19/0686—Injectors
- F02D19/0692—Arrangement of multiple injectors per combustion chamber
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- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
- F02D—CONTROLLING COMBUSTION ENGINES
- F02D41/00—Electrical control of supply of combustible mixture or its constituents
- F02D41/02—Circuit arrangements for generating control signals
- F02D41/14—Introducing closed-loop corrections
- F02D41/1438—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor
- F02D41/1444—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases
- F02D41/1454—Introducing closed-loop corrections using means for determining characteristics of the combustion gases; Sensors therefor characterised by the characteristics of the combustion gases the characteristics being an oxygen content or concentration or the air-fuel ratio
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- Y—GENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
- Y02—TECHNOLOGIES OR APPLICATIONS FOR MITIGATION OR ADAPTATION AGAINST CLIMATE CHANGE
- Y02T—CLIMATE CHANGE MITIGATION TECHNOLOGIES RELATED TO TRANSPORTATION
- Y02T10/00—Road transport of goods or passengers
- Y02T10/10—Internal combustion engine [ICE] based vehicles
- Y02T10/30—Use of alternative fuels, e.g. biofuels
Definitions
- the present invention relates to control of a vehicle including an internal combustion engine (engine).
- Patent Document 1 discloses a technique for gradually returning a target torque setting element to gasoline torque characteristics as time passes after fuel switching.
- drivability may be reduced due to deterioration in engine torque fluctuation even when the target torque immediately before switching is maintained.
- emission deterioration may occur due to a decrease in drivability.
- the present invention has been made to solve the above-described problems, and provides an internal combustion engine control apparatus capable of suppressing deterioration in drivability and emission due to switching of fuel used. With the goal.
- control device for an internal combustion engine executes an engine that can be operated by switching between CNG and liquid fuel, and a fuel that is supplied to the engine between the CNG and the liquid fuel.
- the control device for an internal combustion engine includes an engine and control means.
- the engine can be operated by switching between CNG and liquid fuel.
- the control means is, for example, an ECU (Electronic Control Unit), and when the fuel to be supplied to the engine is switched between CNG and liquid fuel, the air-fuel ratio becomes the same so that the torque fluctuation of the engine becomes equivalent before and after the fuel switching. Switch. That is, the control device for the internal combustion engine sets the air-fuel ratio immediately after the fuel switching to an air-fuel ratio in which the torque fluctuation immediately before the fuel switching is equal to the torque fluctuation immediately after the fuel switching.
- torque fluctuation refers to periodic fluctuations in engine torque.
- the control unit when the control unit performs switching of the fuel from the CNG to the liquid fuel, the air-fuel ratio on the rich side among the air-fuel ratios in which the torque fluctuation is equivalent After switching to the air-fuel ratio, the target air-fuel ratio is gradually approached.
- the “target air-fuel ratio” is a target value of the air-fuel ratio set by the control device of the internal combustion engine after the fuel switching, and specifically, the fuel used, the engine load, etc. after the fuel switching is executed. It refers to the target value of the air-fuel ratio determined based on this. In general, torque fluctuation varies depending on the air-fuel ratio.
- the control device for the internal combustion engine switches the air-fuel ratio on the rich side among the air-fuel ratios where the torque fluctuation is equivalent, so that the actual value of the air-fuel ratio deviates from the command value. Even if it exists, the deterioration of torque fluctuation can be suppressed.
- the control device for the internal combustion engine can perform travel after fuel switching without impairing drivability by gradually approaching the target air-fuel ratio after switching the air-fuel ratio.
- the air-fuel ratio at which the torque fluctuation is equivalent is switched to a lean-side air-fuel ratio
- the target air-fuel ratio is gradually approached.
- the change in torque fluctuation accompanying the change in the air-fuel ratio is smaller in the lean-side air-fuel ratio than in the rich-side air-fuel ratio.
- the control device for the internal combustion engine switches the air-fuel ratio on the lean side from the air-fuel ratio at which the torque fluctuation becomes equal, so that even if the air-fuel ratio deviates from the target, The deterioration of torque fluctuation can be suppressed.
- the control device for the internal combustion engine can perform travel after fuel switching without impairing drivability by gradually approaching the target air-fuel ratio after switching the air-fuel ratio.
- control means may cause the engine torque of the engine to be affected by the effect of switching to an air-fuel ratio at which the torque fluctuation is equivalent before and after the fuel switching.
- the control apparatus for the internal combustion engine has the effect of the control to the air-fuel ratio (hereinafter referred to as “equal torque fluctuation control”) in which the torque fluctuation becomes equal before and after the fuel switching described above, and before and after the fuel switching.
- the “influence” specifically refers to a sense of discomfort such as noise and vibration felt by the driver, that is, the degree of deterioration of drivability.
- the control device for the internal combustion engine the influence caused by the fluctuation of the engine torque when the equal torque fluctuation control is executed is smaller than the influence caused by the deterioration of the torque fluctuation when the equal torque fluctuation control is executed.
- the control device for the internal combustion engine refers to a predetermined map, for example, and makes the above estimation based on the current driving state of the vehicle. By doing so, the control device for the internal combustion engine can execute the equal torque fluctuation control only when the influence of the deterioration of the torque fluctuation is large in the equal torque control, for example, at the time of idling. Can be prevented.
- FIG. 1 is a schematic configuration diagram of an internal combustion engine (engine) 100 to which a control device for an internal combustion engine according to the present invention is applied.
- a solid line arrow in the figure shows an example of a gas flow.
- the internal combustion engine 100 mainly includes a first fuel injection valve 1x, a second fuel injection valve 1y, an intake valve 2, an ignition plug 3, an exhaust valve 4, a cylinder head 5, a cam angle sensor 6, A cylinder 7, a combustion chamber 8, a piston 9, a connecting rod 10, an intake passage 11, an electronic throttle valve 12, a surge tank 13, a water temperature sensor 14, an A / F sensor 15, an exhaust passage 16, Knock sensor 17, fuel delivery pipe 18, gas temperature sensor 19, oil separator 20, regulator 21, shutoff valve 22, gas pressure sensor 23, fuel passage 24, first fuel tank 25, throttle An opening sensor 26, an engine speed sensor 27, a catalyst 28, and an ECU 50 are included.
- FIG. 1 only one cylinder 7 is shown for convenience of explanation, but it is assumed that the internal combustion engine 100 actually has a plurality of cylinders 7.
- the intake air (air) introduced from the outside passes through the intake passage 11, and the electronic throttle valve 12 adjusts the flow rate of the intake air passing through the intake passage 11.
- the opening of the electronic throttle valve 12 is controlled by a control signal supplied from the ECU 50 (hereinafter referred to as “throttle opening”).
- the surge tank 13 is provided on the intake passage 11 and stores air (intake air) and distributes the intake air to the combustion chambers 8 of the respective cylinders through the intake port.
- the combustion chamber 8 is supplied with the fuel injected by the first fuel injection valve (injector) 1x and the second fuel injection valve 1y.
- 1st fuel injection valve 1x injects CNG (compressed natural gas) which is gaseous fuel stored in the 1st fuel tank 25 based on control of ECU50.
- the second fuel injection valve 1y injects liquid fuel stored in a second fuel tank (not shown) based on the control of the ECU 50.
- the liquid fuel is, for example, gasoline, light oil, alcohol such as methanol or ethanol, or a mixed fuel thereof.
- the combustion chamber 8 is provided with an intake valve 2 and an exhaust valve 4.
- the intake valve 2 controls communication / blocking between the intake passage 11 and the combustion chamber 8 by opening and closing.
- the exhaust valve 4 controls communication / blocking between the exhaust passage 16 and the combustion chamber 8 by opening and closing.
- the intake valve 2 and the exhaust valve 4 are each controlled in valve opening timing, valve closing timing, lift amount and the like by a camshaft (not shown).
- the cam angle sensor 6 detects the angle (phase) of the camshaft and supplies a detection signal S6 to the ECU 50.
- the air-fuel mixture of the intake air and fuel supplied as described above in the intake stroke is combusted by being ignited by the spark plug 3 after passing through the compression stroke.
- the piston 9 reciprocates by combustion, the reciprocating motion is transmitted to the crankshaft (not shown) via the connecting rod 10, and the crankshaft rotates.
- the exhaust gas generated by the combustion in the combustion chamber 8 is discharged to the exhaust passage 16 in the exhaust stroke.
- an A / F sensor 15 and a catalyst 28 are provided on the exhaust passage 16.
- the A / F sensor 15 generates an output voltage proportional to the air-fuel ratio of the combusted air-fuel mixture (hereinafter referred to as “air-fuel ratio AF”).
- the output voltage of the A / F sensor 15 is supplied to the ECU 50 by the detection signal S15.
- the engine block is provided with a water temperature sensor 14 and a knock sensor 17.
- the water temperature sensor 14 detects the water temperature (engine water temperature) of the coolant in the water jacket.
- the water temperature sensor 14 supplies a detection signal S14 corresponding to the engine water temperature to the ECU 50.
- the knock sensor 17 detects knocking based on the vibration of the cylinder block. Knock sensor 17 supplies detection signal S17 to ECU 50.
- a gas pressure sensor 23, a shut-off valve 22, a regulator 21, and an oil separator 20 are provided on the fuel passage 24 communicating with the first fuel tank 25.
- the gas pressure sensor 23 detects a gas pressure corresponding to the fuel pressure in the fuel passage 24 and supplies a detection signal S23 to the ECU 50.
- the shutoff valve 22 adjusts the conduction / shutoff of the fuel passage 24 based on the control of the ECU 50.
- the regulator 21 is a mechanism that keeps the fuel pressure constant.
- the oil separator 20 separates impurities from the fuel passing through the fuel passage 24 and supplies the fuel from which the impurities have been removed to the fuel delivery pipe 18.
- the fuel delivery pipe 18 distributes the fuel supplied from the fuel passage 24 to the first fuel injection valves 1x corresponding to the cylinders 7 respectively. Further, the fuel delivery pipe 18 is provided with a gas pressure sensor 19 for detecting the gas pressure (fuel pressure) in the fuel delivery pipe 18. The gas pressure sensor 19 supplies a detection signal S19 corresponding to the gas pressure to the ECU 50.
- the engine speed sensor 27 generates an output pulse indicating the engine speed (hereinafter referred to as “engine speed Ne”).
- the engine speed sensor 27 supplies the output pulse to the ECU 50 by the detection signal S27.
- the ECU 50 includes a CPU (Central Processing Unit), a ROM (Read Only Memory), a RAM (Random Access Memory), and the like (not shown), and performs various controls on each component of the internal combustion engine 100.
- the ECU 50 controls the first and second fuel injection valves 1x, 1y and the like based on the detection signal supplied as described above. Further, the ECU 50 controls the air-fuel ratio AF when the fuel is switched from liquid fuel to CNG or CNG to liquid fuel (hereinafter simply referred to as “fuel switching”).
- the ECU 50 functions as control means in the present invention.
- CNG operation refers to an operation in which fuel injection is performed by the first fuel injection valve 1x, that is, an operation using CNG as a power source
- liquid fuel operation refers to a second operation. This refers to an operation in which fuel injection is performed by the fuel injection valve 1y, that is, an operation using liquid fuel as a power source.
- torque fluctuation Tc refers to periodic fluctuations in engine torque due to intermittent explosion of each cylinder.
- the “target air-fuel ratio AFtag” is a target value of the air-fuel ratio set by the ECU 50 after the fuel switching, and specifically, the air-fuel ratio determined based on the fuel used and the engine load after the fuel switching is performed. It refers to the target value of the fuel ratio AF.
- the ECU 50 switches to the rich-side air-fuel ratio AF among the air-fuel ratios AF in which the torque fluctuation Tc before and after the fuel switching becomes equal. Thereafter, the ECU 50 gradually changes the air-fuel ratio AF to the target air-fuel ratio AFtag. Thereby, ECU50 suppresses the drivability deterioration resulting from the difference in the torque fluctuation Tc before and after fuel switching.
- FIG. 2 is an example of a map showing the relationship between the torque fluctuation Tc and the air-fuel ratio AF for each of the liquid fuel operation and the CNG operation when the engine torque (hereinafter referred to as “engine torque Te”) is equal.
- the graph “Gcng1” shows the relationship between the torque fluctuation Tc during CNG operation and the air-fuel ratio AF
- the graph “Gliq1” shows the relationship between the torque fluctuation Tc during liquid fuel operation and the air-fuel ratio AF. .
- the ECU 50 performs CNG operation at the time of starting the internal combustion engine 100 until the warm-up of the catalyst 28 is completed and in an operation region where emission deterioration is expected in other liquid fuel operation. Thereby, the ECU 50 realizes low emission.
- the ECU 50 determines that the fuel switching should be executed when the state of the internal combustion engine 100 is at the corresponding point Pc.
- the ECU 50 identifies the corresponding points “Pa” and “Pb” on the graph Gliq where the corresponding point Pc and the torque fluctuation Tc are equivalent. Then, immediately after shifting to the liquid fuel operation, the ECU 50 sets the air-fuel ratio AF corresponding to the corresponding point Pa located on the rich side among the corresponding points Pa and Pb to the command value of the air-fuel ratio AF.
- the rate of change of the torque fluctuation Tc with respect to the air-fuel ratio AF is smaller when the air-fuel ratio AF is richer than when it is leaner. That is, during the liquid fuel operation, the stability of the torque fluctuation Tc is higher when the air-fuel ratio AF is richer than when the air-fuel ratio AF is leaner. Therefore, the ECU 50 sets the corresponding point Pa on the rich side of the air-fuel ratio AF among the corresponding points Pa and Pb to the command value of the air-fuel ratio AF, thereby causing a deviation between the command value and the actual value.
- the ECU 50 can suppress the deterioration of drivability due to the difference in the torque fluctuation Tc before and after the fuel switching by setting the air-fuel ratio AF with the same torque fluctuation Tc before and after the fuel switching.
- the ECU 50 sets the air-fuel ratio AF to the corresponding point Pa immediately after the fuel switching, and then gradually brings the air-fuel ratio AF closer to the target air-fuel ratio AFtag corresponding to the corresponding point Petag. Thereby, the ECU 50 smoothly performs the liquid fuel operation after the fuel switching without impairing the drivability.
- the air-fuel ratio AF immediately before switching from the CNG operation to the liquid fuel operation is at the corresponding point “Pd”
- the ECU 50 immediately after shifting to the liquid fuel operation, the air-fuel ratio at the corresponding point Pa located on the rich side of the corresponding points Pa and Pb.
- AF is set to the command value of air-fuel ratio AF.
- the ECU 50 can suppress the deterioration of the torque fluctuation Tc to a minimum even when a deviation occurs between the command value and the actual value of the air-fuel ratio AF.
- the ECU 50 can suppress the deterioration of drivability due to the difference in the torque fluctuation Tc before and after the fuel switching by setting the air-fuel ratio AF with the same torque fluctuation Tc before and after the fuel switching.
- the ECU 50 stores, for example, a map corresponding to FIG. 2 in the memory in advance, and when the fuel is switched from CNG to liquid fuel, the torque fluctuation Tc before and after the fuel switching is referred to by referring to the map or the like.
- the ECU 50 switches to the rich air-fuel ratio AF among the air-fuel ratios AF in which the torque fluctuations Tc before and after the fuel switching are equal. Thereby, ECU50 can suppress deterioration of torque fluctuation Tc.
- the ECU 50 switches to the lean side air-fuel ratio AF out of the air-fuel ratio AF in which the torque fluctuation Tc before and after the switching becomes equal. After that, the ECU 50 gradually changes the air-fuel ratio AF to the target air-fuel ratio AFtag. Thereby, ECU50 suppresses the drivability deterioration and the emission deterioration resulting from the difference of the torque fluctuation Tc before and after fuel switching.
- the ECU 50 determines that the operation should be switched to the CNG operation in an operation region where emission deterioration is expected during the liquid fuel operation.
- the ECU 50 determines that the liquid fuel operation should be switched to the CNG operation when the air-fuel ratio AF is the corresponding point Pa.
- the ECU 50 specifies the corresponding point Pc and the corresponding point Pd on the graph Gcng where the corresponding point Pa and the torque fluctuation Tc are equivalent. Then, immediately after shifting to the CNG operation, the ECU 50 sets the air-fuel ratio AF corresponding to the corresponding point Pc located on the lean side among the corresponding points Pc and Pd to the command value of the air-fuel ratio AF.
- the rate of change of the torque fluctuation Tc with respect to the air-fuel ratio AF is smaller when the air-fuel ratio AF is directed toward the lean side than toward the rich side. That is, during CNG operation, the stability of the torque fluctuation Tc is higher when the air-fuel ratio AF is lean than when the air-fuel ratio AF is rich. Therefore, the ECU 50 sets the corresponding point Pc on the lean side of the air-fuel ratio AF of the corresponding points Pc and Pd to the command value of the air-fuel ratio AF, so that even when a deviation occurs between the command value and the actual value.
- the deterioration of the torque fluctuation Tc can be suppressed to the minimum. Further, the ECU 50 can set the air-fuel ratio AF with the same torque fluctuation Tc before and after the fuel switching, thereby suppressing the drivability deterioration and the emission deterioration due to the difference in the torque fluctuation Tc before and after the fuel switching.
- the ECU 50 sets the air-fuel ratio AF to the corresponding point Pa immediately after the fuel switching, and then gradually brings the air-fuel ratio AF closer to the target air-fuel ratio AFtag corresponding to the corresponding point Pftag. Thereby, the ECU 50 smoothly performs the CNG operation after the fuel change without impairing the drivability.
- the air-fuel ratio AF immediately before switching from the liquid fuel operation to the CNG operation is at the corresponding point Pb.
- the ECU 50 emptyes the corresponding point Pc located on the lean side among the corresponding points Pc and Pd immediately after shifting to the CNG operation. Set to the command value of the fuel ratio AF.
- the ECU 50 stores, for example, a map corresponding to FIG. 2 in the memory in advance, and when the fuel is switched from liquid fuel to CNG, the torque fluctuation Tc before and after the fuel switching is calculated by referring to the map or the like. Switch to an equivalent air-fuel ratio AF. Thereby, ECU50 can suppress the drivability deterioration and the emission deterioration by the change of the torque fluctuation Tc resulting from fuel switching. Further, at this time, the ECU 50 switches to the lean-side air-fuel ratio AF out of the air-fuel ratio AF in which the torque fluctuation Tc before and after the fuel switching becomes equal. Thereby, ECU50 can suppress deterioration of torque fluctuation Tc.
- FIG. 3 is an example of a map showing the relationship between each torque fluctuation Tc and engine torque Te during CNG operation and liquid fuel operation.
- the graph “Gcng2” shows the relationship between the torque fluctuation Tc during CNG operation and the engine torque Te
- the graph “Gliq2” shows the relationship between the torque fluctuation Tc during liquid fuel operation and the engine torque Te.
- the corresponding point “PAtag” is a corresponding point that becomes a target after fuel switching when fuel switching is performed when the state of the internal combustion engine 100 is at the corresponding point “PA”.
- the corresponding point “PBtag” is a corresponding point that becomes a target after fuel switching when fuel switching is performed when the state of the internal combustion engine 100 is at the corresponding point “PB”.
- the torque fluctuation Tc becomes smaller as the engine torque Te is higher in both cases of CNG operation and liquid fuel operation. That is, the higher the engine torque Te, the more stable the combustion of the internal combustion engine 100 and the smaller the torque fluctuation Tc. As shown in the graph Gcng2 and the graph Gliq2, the smaller the engine torque Te, the greater the rate of change of the torque fluctuation Tc with respect to the engine torque Te. Further, the smaller the torque fluctuation Tc, the larger the rate of change of the engine torque Te with respect to the torque fluctuation Tc.
- the ECU 50 determines that the change in the engine torque Te accompanying the equal torque fluctuation control is equal torque. It is determined that it is much smaller than the change in torque fluctuation Tc accompanying the control. Therefore, in this case, the ECU 50 determines that the equal torque fluctuation control has less influence on drivability.
- the ECU 50 shifts the state of the internal combustion engine 100 to the corresponding point “PA1” where the torque fluctuation Tc becomes equal before and after the fuel switching after the fuel switching. After that, the ECU 50 gradually shifts the state of the internal combustion engine 100 from the corresponding point PA1 to the target corresponding point PAtag. In this case, the torque fluctuation Tc does not change before and after the fuel switching, and the fluctuation of the engine torque Te is relatively low. Therefore, when equal torque fluctuation control is executed from the corresponding point PA to the corresponding point PA1, it is estimated that the influence on drivability is small.
- the ECU 50 shifts the state of the internal combustion engine 100 to the corresponding point “PA2” where the engine torque Te becomes equal before and after the fuel switching after the fuel switching. After that, the ECU 50 gradually shifts the state of the internal combustion engine 100 from the corresponding point PA2 to the target corresponding point PAtag. In this case, the torque fluctuation Tc significantly increases when the state of the internal combustion engine 100 shifts from the corresponding point PA to the corresponding point PA2. Therefore, when equal torque control is executed from the corresponding point PA to the corresponding point PA2, drivability may be reduced.
- the ECU 50 determines that the equal torque fluctuation control has less influence on the drivability than the equal torque control when the state of the internal combustion engine 100 is at the corresponding point PA when the fuel is switched from the CNG fuel to the liquid fuel. to decide.
- the ECU 50 determines that the change in the torque fluctuation Tc associated with the equal torque control is much smaller than the change in the engine torque Te associated with the equal torque fluctuation control. Therefore, in this case, the ECU 50 determines that the equal torque control has less influence on drivability.
- the ECU 50 shifts the state of the internal combustion engine 100 to the corresponding point “PB1” where the torque fluctuation Tc becomes equal before and after the fuel switching after the fuel switching. Thereafter, the ECU 50 gradually shifts the state of the internal combustion engine 100 from the corresponding point PB1 to the target corresponding point PBtag. In this case, the change in the engine torque Te when the state of the internal combustion engine 100 shifts from the corresponding point PB to the corresponding point PB1 is relatively large.
- the ECU 50 shifts the state of the internal combustion engine 100 to the corresponding point “PB2” where the engine torque Te becomes equal before and after the fuel switching after the fuel switching. After that, the ECU 50 gradually shifts the state of the internal combustion engine 100 from the corresponding point PB2 to the target corresponding point PBtag. In this case, the change in torque fluctuation Tc when the state of the internal combustion engine 100 is shifted from the corresponding point PB to the corresponding point PB2 is small, and the engine torque Te does not change. Therefore, in this case, the ECU 50 determines that the influence on the drivability by the equal torque control is small.
- the ECU 50 determines that when the state of the internal combustion engine 100 is at the corresponding point PB when the fuel is switched from the CNG fuel to the liquid fuel, the influence on the drivability by the equal torque fluctuation control is the influence on the drivability by the equal torque control. Judged to be larger than
- the ECU 50 executes the control having less influence on drivability among the equal torque fluctuation control and the equal torque control when the fuel is switched. Specifically, the ECU 50 determines which of the equal torque fluctuation control and the equal torque control has less influence on drivability, for example, an internal combustion engine such as a torque fluctuation Tc at the time of fuel switching, an engine torque Te, and an air-fuel ratio AF. Based on the state of the engine 100, a determination is made with reference to a predetermined map. Specifically, the map described above is a map indicating which of the equal torque fluctuation control and the equal torque control has a smaller influence on drivability corresponding to each state of the internal combustion engine 100 at the time of fuel switching. .
- the above-described map is created in advance, for example, by performing a test in each state of the internal combustion engine 100 at the time of fuel switching, and stored in the memory of the ECU 50.
- ECU50 can suppress more reliably the fall of the drivability at the time of fuel switching by setting appropriately the conditions which perform equal torque fluctuation control as mentioned above. Further, the ECU 50 can suppress the deterioration of the emission due to the decrease in drivability.
- FIG. 4 is an example of a flowchart showing a processing procedure when the processing according to the present embodiment is executed.
- the flowchart shown in FIG. 4 is repeatedly executed by the ECU 50 according to a predetermined cycle.
- step S101 the ECU 50 determines whether or not fuel is being used. If the ECU 50 determines that fuel is being used (step S101; Yes), the process proceeds to step S102. On the other hand, when the ECU 50 determines that the fuel is not being used (step S101; No), the process of the flowchart ends.
- the ECU 50 determines whether or not there is a request for fuel switching (step S102). Specifically, the ECU 50 determines whether to perform switching from the CNG operation to the liquid fuel operation or switching from the liquid fuel operation to the CNG operation based on the driving state of the vehicle. And ECU50 advances a process to step S103, when it is judged that fuel switching should be performed (step S102; Yes). On the other hand, when the ECU 50 determines that fuel switching should not be executed (step S102; No), the process of the flowchart is terminated.
- step S103 when ECU50 judges that fuel switching should be performed, while calculating engine torque Te, it calculates torque fluctuation Tc (step S103). For example, the ECU 50 detects the engine speed and the intake air amount from various sensors, and calculates the current engine torque Te by referring to a predetermined map or expression based on these detected values. Further, the ECU 50 calculates, as the torque fluctuation Tc, for example, a difference between the engine torque Te calculated at a predetermined time and the engine torque Te calculated after a lapse of a predetermined time width from the time.
- the ECU 50 determines whether or not the equal torque fluctuation control has a smaller influence on the drivability than the equal torque control (step S104). For example, the ECU 50 performs the above-described determination with reference to a predetermined map based on the engine torque Te and the torque fluctuation Tc calculated in step S103.
- the ECU 50 determines that the equal torque variation control has less influence on the drivability than the equal torque control (step S104; Yes)
- the ECU 50 executes the equal torque variation control at the time of fuel switching. Specifically, the ECU 50 executes step S105 and steps S107 to S110 described later.
- step S104 determines that the equal torque fluctuation control does not affect the drivability less than the equal torque control
- step S104 determines that the ECU 50 determines that the equal torque control is equal.
- step S106 fuel switching is executed by equal torque control. That is, in this case, the ECU 50 maintains the engine torque Te equal before and after fuel switching, and controls the air-fuel ratio AF and the like so that the engine torque Te becomes a predetermined target value after fuel switching.
- step S105 determines whether or not the CNG operation is being executed. If the ECU 50 determines that the CNG operation is being performed (step S105; Yes), the ECU 50 switches to the air-fuel ratio AF on the rich side where the torque fluctuation Tc is equal, along with the fuel switching (step S107). That is, in this case, the ECU 50 switches from the CNG operation to the liquid fuel operation and switches to the rich-side air-fuel ratio AF out of the air-fuel ratio AF in which the torque fluctuation Tc becomes equal before and after the fuel switch.
- the ECU 50 can maintain the torque fluctuation Tc before and after switching from the CNG operation to the liquid fuel operation, and suppress deterioration in drivability. Further, the ECU 50 can suppress the deterioration of the torque fluctuation Tc caused by the difference between the command value of the air-fuel ratio AF and the actual value by switching the air-fuel ratio AF to the rich-side air-fuel ratio AF. Then, the ECU 50 gradually switches the air-fuel ratio AF to the target air-fuel ratio AFtag (step S108).
- step S105 determines that the CNG operation is not being executed (step S105; No), that is, when it is determined that the liquid fuel operation is being executed, the torque change Tc is equal and the lean side is changed together with the fuel switching.
- step S109 switches from the liquid fuel operation to the CNG operation and switches to the lean side air-fuel ratio AF out of the air-fuel ratio AF in which the torque fluctuation Tc becomes equal before and after the fuel switching.
- the ECU 50 can maintain the torque fluctuation Tc before and after switching from the liquid fuel operation to the CNG operation, and suppress deterioration in drivability.
- the ECU 50 can suppress the deterioration of the torque fluctuation Tc caused by the difference between the command value of the air-fuel ratio AF and the actual value by switching the air-fuel ratio AF to the lean side. Then, the ECU 50 gradually switches the air-fuel ratio AF to the target air-fuel ratio AFtag (step S110).
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Mechanical Engineering (AREA)
- General Engineering & Computer Science (AREA)
- Oil, Petroleum & Natural Gas (AREA)
- Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)
- Output Control And Ontrol Of Special Type Engine (AREA)
- Combined Controls Of Internal Combustion Engines (AREA)
Abstract
Description
図1は、本発明に係る内燃機関の制御装置が適用された内燃機関(エンジン)100の概略構成図を示す。図中の実線矢印はガスの流れの一例を示している。
次に、ECU50が実行する制御について具体的に説明する。概略的には、ECU50は、燃料切り替えを行う場合、燃料切り替え前後のトルク変動Tcが同等となる空燃比AFに切り替える。これにより、ECU50は、トルク変動Tcの変化に起因したドライバビリティ低下を抑制する。
ECU50は、CNGから液体燃料へ燃料切り替えを行う場合、燃料切り替え前後のトルク変動Tcが同等になる空燃比AFのうち、リッチ側の空燃比AFに切り替える。その後、ECU50は、空燃比AFを目標空燃比AFtagへ徐々に変更する。これにより、ECU50は、燃料切り替え前後のトルク変動Tcの差に起因したドライバビリティ悪化を抑制する。
ECU50は、液体燃料運転からCNG運転へ切り替えを行う場合、当該切り替え前後のトルク変動Tcが同等になる空燃比AFのうち、リーン側の空燃比AFに切り替える。そして、その後、ECU50は、空燃比AFを目標空燃比AFtagへ徐々に変更する。これにより、ECU50は、燃料切り替え前後のトルク変動Tcの差に起因したドライバビリティ悪化及びエミッション悪化を抑制する。
次に、上述した燃料切り替え前後でトルク変動Tcを同等にする制御(以後、「等トルク変動制御」と呼ぶ。)を実行する条件の好適な例について説明する。概略的には、ECU50は、燃料切り替え時に、等トルク変動制御と、燃料切り替え前後でエンジントルクTeを維持させる制御(以後、「等トルク制御」と呼ぶ。)とのいずれを実行した方がドライバビリティへの影響が小さいか判定する。そして、ECU50は、等トルク変動制御と等トルク制御のうち、ドライバビリティへの影響が少ない方を燃料切り替え時に実行する。
次に、ECU50が実行する処理手順について説明する。図4は、本実施形態に係る処理を実行する場合の処理手順を示すフローチャートの一例である。図4に示すフローチャートは、ECU50により所定の周期に従い繰り返し実行される。
1y 第2燃料噴射弁
2 吸気弁
3 点火プラグ
4 排気弁
7 気筒
9 ピストン
10 コンロッド
11 吸気通路
12 スロットル弁
13 サージタンク
15 A/Fセンサ
21 レギュレータ
50 ECU
100 内燃機関
Claims (4)
- CNGと液体燃料とを切り替えて運転可能なエンジンと、
前記CNGと前記液体燃料とで前記エンジンへ供給する燃料の切り替えを実行する場合、当該燃料の切り替えの前後で前記エンジンのトルク変動が同等となる空燃比に切り替える制御手段と、
を備えることを特徴とする内燃機関の制御装置。 - 前記制御手段は、前記CNGから前記液体燃料へ前記燃料の切り替えを実行する場合、前記トルク変動が同等となる空燃比のうち、リッチ側の空燃比に切り替え、当該空燃比への切り替え後、目標となる空燃比に漸近させる請求項1に記載の内燃機関の制御装置。
- 前記制御手段は、前記液体燃料から前記CNGへ前記燃料の切り替えを実行する場合、前記トルク変動が同等となる空燃比のうち、リーン側の空燃比に切り替え、当該空燃比への切り替え後、目標となる空燃比に漸近させる請求項1または2に記載の内燃機関の制御装置。
- 前記制御手段は、前記燃料の切り替えの前後において、前記トルク変動が同等となる空燃比に切り替えたときの影響が、前記エンジンのエンジントルクを維持させたときの影響よりも小さいと推測される場合に、前記燃料の切り替えの前後で前記エンジンのトルク変動が同等となる空燃比に切り替える請求項1乃至3のいずれか一項に記載の内燃機関の制御装置。
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JP2012505406A JP5418665B2 (ja) | 2010-03-19 | 2010-03-19 | 内燃機関の制御装置 |
EP10847919.7A EP2549084B1 (en) | 2010-03-19 | 2010-03-19 | Control device for internal combustion engine |
US13/520,123 US9032936B2 (en) | 2010-03-19 | 2010-03-19 | Control device for internal combustion engine |
PCT/JP2010/054800 WO2011114508A1 (ja) | 2010-03-19 | 2010-03-19 | 内燃機関の制御装置 |
CN201080057195.3A CN102656353B (zh) | 2010-03-19 | 2010-03-19 | 内燃机的控制装置 |
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US (1) | US9032936B2 (ja) |
EP (1) | EP2549084B1 (ja) |
JP (1) | JP5418665B2 (ja) |
CN (1) | CN102656353B (ja) |
WO (1) | WO2011114508A1 (ja) |
Cited By (3)
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JP2014105790A (ja) * | 2012-11-28 | 2014-06-09 | Toyota Central R&D Labs Inc | 内燃機関の振動抑制装置および方法 |
CN103958860A (zh) * | 2011-11-30 | 2014-07-30 | 爱三工业株式会社 | 双燃料内燃机的燃料供给控制装置以及在双燃料内燃机中切换燃料的方法 |
CN104093955A (zh) * | 2012-02-09 | 2014-10-08 | 丰田自动车株式会社 | 多种燃料内燃机的控制*** |
Families Citing this family (2)
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MX343530B (es) * | 2013-03-21 | 2016-11-09 | Nissan Motor | Dispositivo de control y metodo de control para motores de combustion interna. |
CN104454187A (zh) * | 2014-10-29 | 2015-03-25 | 阿尔特汽车技术股份有限公司 | 油气两用燃料切换控制方法 |
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- 2010-03-19 WO PCT/JP2010/054800 patent/WO2011114508A1/ja active Application Filing
- 2010-03-19 CN CN201080057195.3A patent/CN102656353B/zh not_active Expired - Fee Related
- 2010-03-19 US US13/520,123 patent/US9032936B2/en not_active Expired - Fee Related
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US9032936B2 (en) | 2015-05-19 |
EP2549084A4 (en) | 2013-12-04 |
EP2549084B1 (en) | 2014-12-31 |
EP2549084A1 (en) | 2013-01-23 |
CN102656353B (zh) | 2014-12-10 |
US20120277981A1 (en) | 2012-11-01 |
CN102656353A (zh) | 2012-09-05 |
JP5418665B2 (ja) | 2014-02-19 |
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