WO2015146379A1 - Engine control system - Google Patents

Engine control system Download PDF

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Publication number
WO2015146379A1
WO2015146379A1 PCT/JP2015/054366 JP2015054366W WO2015146379A1 WO 2015146379 A1 WO2015146379 A1 WO 2015146379A1 JP 2015054366 W JP2015054366 W JP 2015054366W WO 2015146379 A1 WO2015146379 A1 WO 2015146379A1
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WO
WIPO (PCT)
Prior art keywords
atmospheric pressure
estimated
fuel injection
engine
injection amount
Prior art date
Application number
PCT/JP2015/054366
Other languages
French (fr)
Japanese (ja)
Inventor
剛 村松
吉川　幸宏
Original Assignee
スズキ株式会社
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by スズキ株式会社 filed Critical スズキ株式会社
Priority to EP15766726.2A priority Critical patent/EP2963272A4/en
Publication of WO2015146379A1 publication Critical patent/WO2015146379A1/en

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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
    • F02D41/24—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means
    • F02D41/26—Electrical control of supply of combustible mixture or its constituents characterised by the use of digital means using computer, e.g. microprocessor
    • 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
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/042—Introducing corrections for particular operating conditions for stopping the engine
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0404—Throttle position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/04—Engine intake system parameters
    • F02D2200/0406—Intake manifold pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/02—Input parameters for engine control the parameters being related to the engine
    • F02D2200/10—Parameters related to the engine output, e.g. engine torque or engine speed
    • F02D2200/101—Engine speed
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/60—Input parameters for engine control said parameters being related to the driver demands or status
    • F02D2200/602—Pedal position
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2200/00—Input parameters for engine control
    • F02D2200/70—Input parameters for engine control said parameters being related to the vehicle exterior
    • F02D2200/703—Atmospheric pressure
    • F02D2200/704—Estimation of atmospheric pressure
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D2250/00—Engine control related to specific problems or objectives
    • F02D2250/14—Timing of measurement, e.g. synchronisation of measurements to the engine cycle
    • 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
    • F02D41/04—Introducing corrections for particular operating conditions
    • F02D41/06—Introducing corrections for particular operating conditions for engine starting or warming up
    • F02D41/062—Introducing corrections for particular operating conditions for engine starting or warming up for starting
    • 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
    • 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
    • F02D41/32—Controlling fuel injection of the low pressure type

Definitions

  • the present invention relates to an engine control system, and more particularly to an engine control system that controls an engine equipped with a fuel injection device (FI) that adjusts a fuel injection amount.
  • FI fuel injection device
  • FI Fuel Injection
  • air pressure is used for fuel injection control, and therefore, detection of atmospheric pressure is required.
  • a large outboard motor equipped with such an engine incorporating an FI includes a battery.
  • the intake pressure sensor for detecting atmospheric pressure can receive power supply from the battery immediately after switching the ignition switch to the on state, and can accurately detect the atmospheric pressure.
  • the detection is performed.
  • a control system that updates the intake pressure as the estimated atmospheric pressure has been proposed (see, for example, Patent Document 1).
  • the detected intake pressure when the throttle is fully opened is updated as the estimated atmospheric pressure, it is possible to detect the estimated atmospheric pressure according to the operating condition of the engine.
  • the estimated atmospheric pressure is updated at a timing when the throttle opening is near the fully open position. For this reason, when the throttle opening does not reach the fully open position, the difference between the maximum intake pressure at the start of the engine and the actual atmospheric pressure may increase. In this case, the fuel injection control is performed based on the estimated atmospheric pressure having a difference from the actual atmospheric pressure, and it is difficult to appropriately perform the fuel injection control.
  • the present invention has been made in view of such circumstances, and an object of the present invention is to provide an engine control system capable of appropriately performing fuel injection control regardless of the throttle opening state.
  • An engine control system includes an engine speed detection unit that detects an engine speed, a pressure detection unit that detects an intake pipe pressure downstream of a throttle valve, and an intake pipe pressure that is detected by the pressure detection unit.
  • An atmospheric pressure estimating means for estimating an atmospheric pressure, a storage means for storing the estimated atmospheric pressure output from the atmospheric pressure estimating means as a learning atmospheric pressure after the engine is stopped, an engine speed and a fuel injection amount based on the estimated atmospheric pressure
  • the estimated atmospheric pressure estimated when the engine is started is compared with the learning atmospheric pressure stored in the storage means, and if the difference between the two is smaller than a predetermined value, the learning stored in the storage means is stored.
  • the fuel injection amount is calculated using the atmospheric pressure. For this reason, for example, even when the throttle opening does not reach the fully open position, the fuel injection amount can be calculated using the stored learned atmospheric pressure. As a result, fuel injection control can be performed appropriately regardless of the throttle opening situation.
  • the atmospheric pressure estimating means when the difference between the estimated atmospheric pressure and the learned atmospheric pressure is greater than or equal to a predetermined value, the atmospheric pressure estimating means preferably adjusts the estimated atmospheric pressure according to the engine speed.
  • the estimated atmospheric pressure can be adjusted following the intake pressure that fluctuates according to the engine speed, so that the estimated atmospheric pressure can be updated more accurately and in a wider range.
  • the fuel injection amount calculation means may calculate a fuel injection amount suitable for lean burn control from non-lean burn control when the difference between the estimated atmospheric pressure and the learned atmospheric pressure is a predetermined value or less. It is preferable to calculate. In this case, since the fuel injection amount suitable for lean burn control is calculated only when the difference between the estimated atmospheric pressure estimated from the intake pipe pressure and the learned atmospheric pressure is equal to or less than a predetermined value, the engine is rapidly increased. The shift to lean burn control can be realized while avoiding a decrease in output.
  • FIG. 1 is a schematic diagram showing an intake structure of an engine to which an engine control system according to the present embodiment is applied. It is a flowchart for demonstrating the operation
  • the present embodiment will be described in detail with reference to the accompanying drawings.
  • the application target is not limited to the outboard motor and can be appropriately changed.
  • the present invention can be applied to a vehicle such as a motorcycle having a configuration in which the atmospheric pressure is estimated by an intake pressure sensor.
  • the engine control system according to the present invention is preferably used for an outboard motor or the like not equipped with a battery, but may be applied to an outboard motor or the like equipped with a battery.
  • FIG. 1 is a diagram showing a schematic configuration of an engine control system according to the present embodiment.
  • FIG. 2 is a schematic diagram showing an intake structure of an engine to which the engine control system according to the present embodiment is applied.
  • ECM Engine Control Module
  • FIG. 1 only the components around the engine and ECM (Engine Control Module) necessary for applying the present invention are shown to simplify the description, and other components are omitted.
  • the engine control system according to the present embodiment is applied to an outboard motor or the like not equipped with a battery.
  • the engine control system 1 includes an engine 2 that is an internal combustion engine and an ECM 3 that controls the engine 2.
  • the engine 2 is provided with a recoil starter 4 and a generator (AC generator) 5.
  • An engine speed sensor 6, an intake pressure sensor 7, a throttle opening sensor 8, and an injector 9 are connected to the ECM 3.
  • the engine speed sensor 6 and the intake pressure sensor 7 constitute a speed detection means and a pressure detection means in the claims.
  • the engine 2 is, for example, a direct-acting DOHC (Double Overhead Camshaft) engine, and includes a crankshaft 21, a cylinder 22, a cylinder head 23, and the like (see FIG. 2).
  • DOHC Double Overhead Camshaft
  • a piston 24 is accommodated in the cylinder 22 so as to reciprocate up and down.
  • the crankshaft 21 and the piston 24 are connected by a connecting rod 25.
  • the crankshaft 21 is rotated via the connecting rod 25.
  • a combustion chamber 231 is provided inside the cylinder head 23.
  • the cylinder head 23 is provided with an intake valve 26 and an exhaust valve 27 corresponding to the intake port and the exhaust port.
  • a pair of rocker arms 28 a and 28 b are provided corresponding to the intake valve 26 and the exhaust valve 27.
  • the cylinder head 23 is provided with a camshaft 29 that drives the rocker arms 28a and 28b.
  • a cam chain (not shown) is bridged between the crankshaft 21 and the camshaft 29, and the rotation of the crankshaft 21 is transmitted to the camshaft 29 via the cam chain.
  • the cylinder head 23 is provided with an ignition device 30 (spark plug) that ignites the air-fuel mixture in the combustion chamber 231.
  • the ignition device 30 ignites at a predetermined timing based on the ignition signal supplied from the ECM 3.
  • the recoil starter 4 functions as a manual starter and is provided at one end of the crankshaft 21 of the engine 2.
  • a pulley (not shown) is accommodated inside the recoil starter 4.
  • a rope 41 is wound around the pulley with one end exposed from the housing of the recoil starter 4. When the operator (driver) pulls the end of the rope 41 by hand, a rotational force can be applied to the crankshaft 21 of the engine 2.
  • the generator 5 is provided at the same end of the recoil starter 4 in the crankshaft 21 of the engine 2.
  • the generator 5 is composed of an AC magnet generator.
  • the AC magnet generator includes a permanent magnet provided at the other end of the crankshaft 21 and a power generation coil disposed to face the permanent magnet. When the permanent magnet rotates with the rotation of the crankshaft 21, an electromotive force is generated and the power generation coil generates power.
  • the ECM 3 includes a calculation unit such as a CPU and a storage unit such as a RAM and a ROM.
  • the ECM 3 is driven by generated power generated in the generator 5 as the engine 2 is driven.
  • the ECM 3 functions as the atmospheric pressure estimation unit 31, the atmospheric pressure storage unit 32, and the fuel injection amount calculation unit 33 when the CPU executes a program stored in the ROM. Details of these components will be described later.
  • the atmospheric pressure estimation unit 31, the atmospheric pressure storage unit 32, and the fuel injection amount calculation unit 33 constitute an atmospheric pressure estimation unit, a storage unit, and a fuel injection amount calculation unit in the claims, respectively.
  • the engine speed sensor 6 is disposed, for example, facing the outer periphery of the crank magnet 211 that rotates integrally with the crankshaft 21 (see FIG. 2).
  • the crank magneto 211 has a generally disk shape, and a plurality of protrusions 211a are formed on the outer peripheral surface thereof.
  • the engine speed sensor 6 detects the engine speed based on, for example, the number of protrusions 211a that pass through the detection region as the crankshaft 21 rotates.
  • the engine speed detected by the engine speed sensor 6 is output to the ECM 3 (more specifically, the atmospheric pressure estimation unit 31 and the fuel injection amount calculation unit 33).
  • the intake pressure sensor 7 is disposed in an intake pipe 201 connected to an intake port (see FIG. 2).
  • the intake pipe 201 is provided with a throttle valve 10.
  • the intake pressure sensor 7 is disposed on the intake pipe 201 located downstream of the throttle valve 10 (left side shown in FIG. 2) and between the intake port and the pressure in the intake pipe 201 (intake air). Tube pressure).
  • the intake pipe pressure detected by the intake pressure sensor 7 is output to the ECM 3 (more specifically, the atmospheric pressure estimation unit 31 and the fuel injection amount calculation unit 33).
  • the throttle opening sensor 8 is disposed, for example, at a position corresponding to the throttle valve 10 in the intake pipe 201 (see FIG. 2).
  • the throttle opening sensor 8 detects the opening (throttle opening) of the throttle valve 10.
  • the throttle opening detected by the throttle opening sensor 8 is output to the ECM 3.
  • the injector 9 functions as an electronic fuel injection device, and is attached to the intake pipe 201 of the engine 2 (see FIG. 2).
  • the injector 9 is configured to be able to inject fuel supplied from a fuel pump (not shown) into the intake pipe 201 in response to a drive signal from the ECM 3.
  • the atmospheric pressure estimation unit 31 estimates the atmospheric pressure from the pressure of the intake pipe 201 (intake pipe pressure) detected by the intake pressure sensor 7 (estimated atmospheric pressure). More specifically, the atmospheric pressure estimation unit 31 estimates the maximum intake pipe pressure within a predetermined time from the start of the engine 2 as the estimated atmospheric pressure.
  • the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 is output to the fuel injection amount calculation unit 33, and is output to the atmospheric pressure storage unit 32 when a learning atmospheric pressure update condition described later is satisfied.
  • the atmospheric pressure storage unit 32 stores the estimated atmospheric pressure output from the atmospheric pressure estimation unit 31 as a learning atmospheric pressure.
  • the atmospheric pressure storage unit 32 stores the estimated atmospheric pressure as the learning atmospheric pressure after the engine 2 is stopped.
  • This learned atmospheric pressure is used as a comparison object with the estimated atmospheric pressure estimated by the atmospheric pressure estimating unit 31 during the fuel injection control when the engine 2 is started next time.
  • a nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) is preferably used.
  • the fuel injection amount calculation unit 33 calculates the fuel injection amount by the injector 9.
  • the fuel injection amount calculation unit 33 is based on the engine speed detected by the engine speed sensor 6 and the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 or the learned atmospheric pressure stored in the atmospheric pressure storage unit 32. To calculate the fuel injection amount. More specifically, the fuel injection amount calculation unit 33 compares the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 with the learning atmospheric pressure stored in the atmospheric pressure storage unit 32, and the difference between the two is determined. When less than a predetermined value, the learning atmospheric pressure is used to calculate the fuel injection amount. When the difference between the two is equal to or greater than the predetermined value, the estimated atmospheric pressure estimated based on the intake pipe pressure is used. Then, the fuel injection amount is calculated.
  • the fuel injection amount calculation unit 33 converts the control mode (non-lean burn control, lean burn control) according to the calculation result of the fuel injection amount when a certain condition is satisfied. As will be described in detail later, when the difference between the estimated atmospheric pressure corrected by the atmospheric pressure estimation unit 31 and the learning atmospheric pressure is equal to or less than a predetermined value, the non-lean burn control mode is shifted to the lean burn control mode, and this lean The fuel injection amount is adjusted (calculated) so as to be suitable for the burn control mode.
  • the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 during the fuel injection control and the atmospheric pressure storage unit 32 are stored. Compare with the learning atmospheric pressure. Then, by calculating the fuel injection amount using the estimated atmospheric pressure or the learning atmospheric pressure according to the comparison result between them, the fuel injection control is appropriately performed regardless of the throttle opening degree.
  • FIG. 3 is a flowchart for explaining an outline of the operation at the time of fuel injection control in the engine control system 1 according to the present embodiment.
  • step (hereinafter referred to as “ST”) 301) fuel injection amount calculation processing (injection amount calculation processing: ST302). )
  • fuel injection processing injection processing: ST303).
  • FIG. 3 illustrates a case where the injection amount calculation process and the injection process shown in ST302 and ST303 are executed after the atmospheric pressure learning process shown in ST301 is executed.
  • the injection amount calculation process and the injection process shown in ST302 and ST303 are performed in parallel with the atmospheric pressure learning process shown in ST301.
  • the atmospheric pressure learning process is executed while the engine 2 is operating (ST301).
  • This atmospheric pressure learning process is a process of learning a learning atmospheric pressure referred to during fuel injection control.
  • the learning atmospheric pressure is learned (updated) when a predetermined update condition is satisfied.
  • the learning atmospheric pressure at that time is stored in the atmospheric pressure storage unit 32.
  • the injection amount calculation process is executed in parallel with this atmospheric pressure learning process (ST302).
  • This injection amount calculation processing is performed by the learning atmospheric pressure stored in the atmospheric pressure storage unit 32 and the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 (the estimated atmospheric pressure based on the intake pipe pressure detected by the intake pressure sensor 7).
  • This is a process for calculating the fuel injection amount by the injector 9 based on the difference from ().
  • the control mode conversion (transition) is determined together with the calculation of the fuel injection amount, and the fuel injection amount is adjusted according to the determination result. More specifically, when the difference between the estimated atmospheric pressure corrected by the atmospheric pressure estimation unit 31 and the learned atmospheric pressure is equal to or less than a certain value, the non-lean burn control mode is converted to the lean burn control mode, and this lean burn The fuel injection amount is adjusted to be suitable for the control mode.
  • the injection process is executed (ST303).
  • fuel is injected from the injector 9 based on the fuel injection amount calculated in the injection amount calculation process.
  • the injection amount calculation process and the injection process shown in ST302 and ST303 are repeatedly executed while the engine 2 is operating.
  • FIG. 4 is a flowchart for explaining the atmospheric pressure learning process in the engine control system 1 according to the present embodiment.
  • the pressure in the intake pipe 201 is detected by the intake pressure sensor 7 (ST401).
  • the detected intake pipe pressure is output to the atmospheric pressure estimation unit 31 of the ECM 3.
  • the atmospheric pressure estimation unit 31 estimates the maximum intake pipe pressure within a predetermined time from the start of the engine 2 as the current atmospheric pressure, and obtains the estimated atmospheric pressure (ST402).
  • the fuel injection amount calculation unit 33 reads the learning atmospheric pressure (more specifically, stored in the atmospheric pressure storage unit 32). The learning atmospheric pressure stored in the atmospheric pressure storage unit 32 when the previous operation was stopped is read (ST403). Then, the fuel injection amount calculation unit 33 determines an atmospheric pressure update determination value (hereinafter simply referred to as “determination value”) in which a difference between the estimated atmospheric pressure estimated in ST402 and the learned atmospheric pressure stored when the previous operation was stopped is predetermined. It is determined whether or not (ST404).
  • determination value an atmospheric pressure update determination value
  • the throttle opening is continuously opened for a certain period of time by the throttle opening sensor 8 (WOT (Wide Open Throttle)). Is determined) (ST405).
  • WOT Wide Open Throttle
  • “1” is set to a flag (hereinafter referred to as “learning execution flag”) indicating whether or not learning atmospheric pressure is executed (ST406).
  • ST404 and ST405 are processes for determining a learning atmospheric pressure update condition. If both are positively determined, the learning atmospheric pressure update condition is satisfied. In addition, when it is not a WOT state or when the WOT state is not continued for a certain time, the determination of ST405 is repeated.
  • the atmospheric pressure estimation unit 31 adjust the estimated atmospheric pressure according to the engine speed.
  • the atmospheric pressure estimation unit 31 can adjust the estimated atmospheric pressure based on, for example, the estimated atmospheric pressure adjustment map shown in FIG.
  • FIG. 5 is an explanatory diagram of an example of an estimated atmospheric pressure adjustment map used in the engine control system 1 according to the present embodiment.
  • the detected value Pb from the intake pressure sensor 7 is associated with the vertical axis
  • the engine rotational speed Ne with the engine rotational speed sensor 6 is associated with the horizontal axis.
  • the atmospheric pressure estimation unit 31 adjusts it according to the engine speed received from the engine speed sensor 6 based on the estimated atmospheric pressure adjustment map shown in FIG. be able to.
  • the atmospheric pressure estimation unit 31 calculates the estimated high pressure.
  • the atmospheric pressure can be adjusted to “68 kPa” (see Pb3 and Ne2 shown in FIG. 5).
  • the atmospheric pressure estimation unit 31 estimates the estimated high pressure.
  • the atmospheric pressure can be adjusted to “83 kPa” (see Pb5 and Ne7 shown in FIG. 5).
  • the atmospheric pressure estimating unit 31 adjusts the estimated atmospheric pressure according to the engine speed, and thus varies according to the engine speed.
  • the estimated atmospheric pressure can be adjusted following the intake pipe pressure. As a result, it is possible to obtain the estimated atmospheric pressure in a more accurate and wide range following the intake pipe pressure which varies depending on the engine speed.
  • the atmospheric pressure estimation unit 31 After “1” is set to the learning execution flag in ST406, the atmospheric pressure estimation unit 31 performs a process for correcting the estimated atmospheric pressure (estimated atmospheric pressure correction process) (ST407).
  • the estimated atmospheric pressure (estimated atmospheric pressure estimated in ST402) is corrected based on the predetermined atmospheric pressure learning filter value and the learned atmospheric pressure.
  • the corrected estimated atmospheric pressure X corrected by the estimated atmospheric pressure correction process is calculated based on the following (Equation 1).
  • “F1” indicates an atmospheric pressure learning filter value.
  • X F1 ⁇ learning atmospheric pressure + (1-F1) ⁇ estimated atmospheric pressure (Formula 1)
  • the fuel injection amount calculation unit 33 calculates the difference between the corrected estimated atmospheric pressure (corrected estimated atmospheric pressure) and the current estimated atmospheric pressure estimated from the intake pipe pressure. It is determined whether or not it is equal to or less than a determination value (ST408). If the difference between the corrected estimated atmospheric pressure and the current estimated atmospheric pressure is not less than the determination value, the process returns to ST405, and the processes of ST405 to ST408 are performed again.
  • mode conversion flag a flag indicating whether or not conversion to the lean burn control mode is permitted. “1” is set (ST409).
  • mode conversion flag is set to “1”
  • conversion from the non-lean burn control mode to the lean burn control mode is permitted. That is, the transition to the lean burn control mode is allowed only when the difference between the corrected estimated atmospheric pressure and the current estimated atmospheric pressure is equal to or smaller than the determination value.
  • the processing after ST409 is performed. That is, after the mode conversion flag is set to “1” in ST409, the ON state of the ignition switch is determined in ST410. If the ignition switch is in the OFF state, the learning atmospheric pressure is updated in ST411. After the atmospheric pressure learning value is updated in ST411 through such a series of processes, the atmospheric pressure learning process ends.
  • FIG. 6 is a flowchart for explaining an injection amount calculation process in the engine control system according to the present embodiment.
  • the pressure in the intake pipe 201 is detected by the intake pressure sensor 7 (ST601).
  • the detected intake pipe pressure is output to the atmospheric pressure estimation unit 31 of the ECM 3.
  • the atmospheric pressure estimation unit 31 estimates the maximum intake pipe pressure within a predetermined time from the start of the engine 2 as the current atmospheric pressure, and obtains the estimated atmospheric pressure (ST602).
  • the fuel injection amount calculation unit 33 reads the learning atmospheric pressure stored in the atmospheric pressure storage unit 32 (ST603). Then, the fuel injection amount calculation unit 33 determines whether the difference between the estimated atmospheric pressure estimated in ST402 and the learned atmospheric pressure is equal to or greater than a determination value (atmospheric pressure update determination value) (ST604).
  • the fuel injection amount calculation unit 33 calculates the fuel injection amount using the estimated atmospheric pressure estimated in ST602 (ST605). ).
  • the fuel injection amount calculation unit 33 calculates the fuel injection amount using the learning atmospheric pressure stored in the atmospheric pressure storage unit 32. (ST606).
  • the fuel injection amount calculation unit 33 determines whether “1” is set in the mode conversion flag (ST607). This determination is to determine whether the transition from the non-lean burn control mode to the lean burn control mode is permitted.
  • the fuel injection amount calculation unit 33 adjusts the fuel injection amount calculated in ST606 to a fuel injection amount suitable for the lean burn control mode (ST608). That is, the fuel injection amount is adjusted so that the air-fuel ratio is lower than the ideal air-fuel ratio in the non-lean burn control mode.
  • the fuel injection amount calculation unit 33 skips ST608 and does not adjust to the fuel injection amount suitable for the lean burn control mode.
  • the injection amount calculation process is completed.
  • the fuel injection amount calculated (adjusted) in this injection amount calculation processing is used in the injection processing shown in ST303 in FIG. 3, and fuel corresponding to the fuel injection amount is injected from the injector 9 into the intake pipe 201.
  • the fuel injection amount calculated based on either the estimated atmospheric pressure based on the intake pipe pressure or the learned atmospheric pressure stored in the atmospheric pressure storage unit 32 is injected.
  • the estimated atmospheric pressure estimated when the engine is started is compared with the learned atmospheric pressure stored in the atmospheric pressure storage unit 32.
  • the fuel injection amount is calculated using the learning atmospheric pressure
  • the difference between the two is equal to or larger than the predetermined value (determination value)
  • the fuel injection amount is estimated from the intake pipe pressure.
  • the fuel injection amount is calculated using the estimated atmospheric pressure. For this reason, for example, even when the throttle opening does not reach the fully open position, the fuel amount can be calculated using the stored learning atmospheric pressure. As a result, fuel injection control can be performed appropriately regardless of the throttle opening situation.
  • the fuel injection amount calculation unit 33 performs the lean control from the non-lean burn control when the difference between the estimated atmospheric pressure and the learning atmospheric pressure is a predetermined value (determination value) or less. A fuel injection amount suitable for burn control is calculated. As a result, the fuel injection amount suitable for lean burn control is calculated only when the difference between the estimated atmospheric pressure and the learning atmospheric pressure is equal to or less than a predetermined value, so that a sudden decrease in engine output is avoided. Lean burn operation can be realized.
  • the learning atmospheric pressure is always updated in the atmospheric pressure storage unit 32 when the engine is stopped.
  • the timing for always updating the learning atmospheric pressure is limited to when the engine is stopped. It is not a thing and it can change suitably.
  • the learning atmospheric pressure may be updated when the emergency stop switch is operated by an operator (driver) (that is, when the emergency stop switch is turned on).
  • the present invention has an effect that the fuel injection control can be appropriately performed regardless of the throttle opening state, and in particular, the fuel injection amount is not provided with the battery but is generated by the power generated by the generator. It is useful for vehicles such as outboard motors and motorcycles equipped with an engine that drives a fuel injection device that adjusts fuel consumption.

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  • Engineering & Computer Science (AREA)
  • Chemical & Material Sciences (AREA)
  • Combustion & Propulsion (AREA)
  • Mechanical Engineering (AREA)
  • General Engineering & Computer Science (AREA)
  • Computer Hardware Design (AREA)
  • Microelectronics & Electronic Packaging (AREA)
  • Combined Controls Of Internal Combustion Engines (AREA)
  • Electrical Control Of Air Or Fuel Supplied To Internal-Combustion Engine (AREA)

Abstract

The purpose of the present invention is to control fuel injection appropriately regardless of throttle aperture status. An engine control system (1) is provided with a fuel injection quantity calculation unit (33) for calculating a fuel injection quantity on the basis of an estimated atmospheric pressure, estimated by an atmospheric pressure estimation unit (31) on the basis of an intake pipe pressure, and an engine speed detected by an engine speed sensor (6). The fuel injection quantity calculation unit compares the estimated atmospheric pressure estimated when an engine starts and a learned atmospheric pressure stored in an atmospheric pressure storage unit (32), and if the difference between the estimated atmospheric pressure and the learned atmospheric pressure is less than a prescribed value, the calculation unit calculates the fuel injection quantity using the learned atmospheric pressure, and if the difference between the estimated atmospheric pressure and the learned atmospheric pressure is equal to or greater than the prescribed value, calculates the fuel injection quantity using the estimated atmospheric pressure.

Description

エンジン制御システムEngine control system
　本発明は、エンジン制御システムに関し、特に、燃料噴射量を調整する燃料噴射装置（ＦＩ：Fuel　Injection）を備えたエンジンを制御するエンジン制御システムに関する。 The present invention relates to an engine control system, and more particularly to an engine control system that controls an engine equipped with a fuel injection device (FI) that adjusts a fuel injection amount.
　吸気圧センサを用いて吸気量を推定する燃料噴射装置（ＦＩ：Fuel　Injection）においては、燃料噴射制御に空気密度を使用するため、大気圧の検出が必要となる。一般に、このようなＦＩが組み込まれたエンジンを搭載する大型船外機ではバッテリを備えている。このため、大気圧検出のための吸気圧センサは、イグニッションスイッチをオン状態に切り替えた直後にバッテリから電力供給を受けることができ、正確に大気圧を検出することができる。 In a fuel injection device (FI: Fuel Injection) that estimates an intake air amount using an intake pressure sensor, air pressure is used for fuel injection control, and therefore, detection of atmospheric pressure is required. In general, a large outboard motor equipped with such an engine incorporating an FI includes a battery. For this reason, the intake pressure sensor for detecting atmospheric pressure can receive power supply from the battery immediately after switching the ignition switch to the on state, and can accurately detect the atmospheric pressure.
　近年、小型船外機においても、ＦＩが組み込まれたエンジンを搭載するものが普及しつつある。このような小型船外機においても、適切に燃料噴射制御を行うために大気圧の検出が必要となる。しかしながら、小型船外機においてはバッテリを備えず、発電機（ＡＣジェネレータ）による自己発電のみでエンジン負荷を駆動する機種も多い。これらの小型船外機においては、エンジン始動後に吸気圧センサにて大気圧を推定することが行われている。 In recent years, small outboard motors equipped with an engine incorporating FI are becoming popular. Even in such a small outboard motor, it is necessary to detect atmospheric pressure in order to appropriately perform fuel injection control. However, many small outboard motors do not have a battery and drive the engine load only by self-power generation by a generator (AC generator). In these small outboard motors, the atmospheric pressure is estimated by an intake pressure sensor after the engine is started.
　例えば、エンジン始動時の最大吸気圧を推定大気圧とし、スロットル開度が全開付近となるタイミングで検出した吸気圧（検出吸気圧）がその時点の推定大気圧よりも高い場合には、その検出吸気圧を推定大気圧として更新する制御システムが提案されている（例えば、特許文献１参照）。この制御システムにおいては、スロットル全開時の検出吸気圧が推定大気圧として更新されるので、エンジンの稼働状況に応じた推定大気圧を検出することができる。 For example, if the maximum intake pressure at engine startup is the estimated atmospheric pressure, and the intake pressure (detected intake pressure) detected at the timing when the throttle opening is nearly fully open is detected, the detection is performed. A control system that updates the intake pressure as the estimated atmospheric pressure has been proposed (see, for example, Patent Document 1). In this control system, since the detected intake pressure when the throttle is fully opened is updated as the estimated atmospheric pressure, it is possible to detect the estimated atmospheric pressure according to the operating condition of the engine.
特開２０１３－１９９９１５号公報JP 2013-199915 A
　しかしながら、上述した特許文献１記載の制御システムにおいては、スロットル開度が全開付近となるタイミングで推定大気圧が更新される。このため、スロットル開度が全開付近に至らない場合には、エンジン始動時の最大吸気圧と実際の大気圧との差が大きくなる場合がある。この場合、実際の大気圧と差を有した推定大気圧に基づいて燃料噴射制御が行われることとなり、適切に燃料噴射制御を行うことが困難となる。 However, in the control system described in Patent Document 1 described above, the estimated atmospheric pressure is updated at a timing when the throttle opening is near the fully open position. For this reason, when the throttle opening does not reach the fully open position, the difference between the maximum intake pressure at the start of the engine and the actual atmospheric pressure may increase. In this case, the fuel injection control is performed based on the estimated atmospheric pressure having a difference from the actual atmospheric pressure, and it is difficult to appropriately perform the fuel injection control.
　本発明はこのような実情に鑑みてなされたものであり、スロットル開度の状況に関わらず適切に燃料噴射制御を行うことができるエンジン制御システムを提供することを目的とする。 The present invention has been made in view of such circumstances, and an object of the present invention is to provide an engine control system capable of appropriately performing fuel injection control regardless of the throttle opening state.
　本発明のエンジン制御システムは、エンジン回転数を検出する回転数検出手段と、スロットルバルブの下流の吸気管圧を検出する圧力検出手段と、前記圧力検出手段により検出された吸気管圧から推定大気圧を推定する大気圧推定手段と、前記大気圧推定手段から出力された推定大気圧を学習大気圧としてエンジン停止後に記憶する記憶手段と、エンジン回転数及び前記推定大気圧に基づいて燃料噴射量を算出する燃料噴射量算出手段と、を備え、前記燃料噴射量算出手段は、エンジン始動の際に推定された前記推定大気圧と前記記憶手段に記憶された前記学習大気圧とを比較し、前記推定大気圧と前記学習大気圧との差が所定値より小さい場合に当該学習大気圧を利用して燃料噴射量を算出する一方、前記推定大気圧と前記学習大気圧との差が所定値以上の場合に当該推定大気圧を利用して燃料噴射量を算出することを特徴とする。 An engine control system according to the present invention includes an engine speed detection unit that detects an engine speed, a pressure detection unit that detects an intake pipe pressure downstream of a throttle valve, and an intake pipe pressure that is detected by the pressure detection unit. An atmospheric pressure estimating means for estimating an atmospheric pressure, a storage means for storing the estimated atmospheric pressure output from the atmospheric pressure estimating means as a learning atmospheric pressure after the engine is stopped, an engine speed and a fuel injection amount based on the estimated atmospheric pressure A fuel injection amount calculating means for calculating the fuel injection amount, the fuel injection amount calculating means comparing the estimated atmospheric pressure estimated at the time of engine start and the learning atmospheric pressure stored in the storage means, When the difference between the estimated atmospheric pressure and the learned atmospheric pressure is smaller than a predetermined value, the fuel injection amount is calculated using the learned atmospheric pressure, while the estimated atmospheric pressure and the learned atmospheric pressure Difference and calculates a fuel injection quantity by using the estimated atmospheric pressure equal to or larger than the predetermined value.
　この構成によれば、エンジン始動の際に推定された推定大気圧と記憶手段に記憶された学習大気圧とを比較し、両者の差が所定値より小さい場合には記憶手段に記憶された学習大気圧を利用して燃料噴射量が算出される。このため、例えば、スロットル開度が全開付近に至らない場合であっても、記憶された学習大気圧を利用して燃料噴射量を算出することができる。この結果、スロットル開度の状況に関わらず適切に燃料噴射制御を行うことが可能となる。 According to this configuration, the estimated atmospheric pressure estimated when the engine is started is compared with the learning atmospheric pressure stored in the storage means, and if the difference between the two is smaller than a predetermined value, the learning stored in the storage means is stored. The fuel injection amount is calculated using the atmospheric pressure. For this reason, for example, even when the throttle opening does not reach the fully open position, the fuel injection amount can be calculated using the stored learned atmospheric pressure. As a result, fuel injection control can be performed appropriately regardless of the throttle opening situation.
　上記エンジン制御システムにおいて、前記推定大気圧と前記学習大気圧との差が所定値以上の場合、前記大気圧推定手段は、エンジン回転数に応じて前記推定大気圧を調整することが好ましい。この場合には、エンジン回転数に応じて変動する吸気圧に追随して推定大気圧を調整することができるので、より正確且つ広範な範囲で推定大気圧を更新することができる。 In the engine control system, when the difference between the estimated atmospheric pressure and the learned atmospheric pressure is greater than or equal to a predetermined value, the atmospheric pressure estimating means preferably adjusts the estimated atmospheric pressure according to the engine speed. In this case, the estimated atmospheric pressure can be adjusted following the intake pressure that fluctuates according to the engine speed, so that the estimated atmospheric pressure can be updated more accurately and in a wider range.
　また、上記エンジン制御システムにおいて、前記燃料噴射量算出手段は、前記推定大気圧と前記学習大気圧との差が所定値以下の場合に非リーンバーン制御からリーンバーン制御に適した燃料噴射量を算出することが好ましい。この場合には、吸気管圧から推定された推定大気圧と学習大気圧との差が所定値以下の場合に限ってリーンバーン制御に適した燃料噴射量が算出されることから、急激にエンジン出力が低下することを回避しつつリーンバーン制御への移行を実現することができる。 In the engine control system, the fuel injection amount calculation means may calculate a fuel injection amount suitable for lean burn control from non-lean burn control when the difference between the estimated atmospheric pressure and the learned atmospheric pressure is a predetermined value or less. It is preferable to calculate. In this case, since the fuel injection amount suitable for lean burn control is calculated only when the difference between the estimated atmospheric pressure estimated from the intake pipe pressure and the learned atmospheric pressure is equal to or less than a predetermined value, the engine is rapidly increased. The shift to lean burn control can be realized while avoiding a decrease in output.
　本発明のエンジン制御システムによれば、スロットル開度の状況に関わらず適切に燃料噴射制御を行うことが可能となる。 According to the engine control system of the present invention, it is possible to appropriately perform fuel injection control regardless of the state of the throttle opening.
本実施の形態に係るエンジン制御システムの概略構成を示す図である。It is a figure which shows schematic structure of the engine control system which concerns on this Embodiment. 本実施の形態に係るエンジン制御システムが適用されるエンジンの吸気構造を示す模式図である。1 is a schematic diagram showing an intake structure of an engine to which an engine control system according to the present embodiment is applied. 本実施の形態に係るエンジン制御システムにおける燃料噴射制御時の動作概要を説明するためのフロー図である。It is a flowchart for demonstrating the operation | movement outline | summary at the time of the fuel injection control in the engine control system which concerns on this Embodiment. 本実施の形態に係るエンジン制御システムにおける大気圧学習処理を説明するためのフロー図である。It is a flowchart for demonstrating the atmospheric pressure learning process in the engine control system which concerns on this Embodiment. 本実施の形態に係るエンジン制御システムで利用される推定大気圧調整マップの一例の説明図である。It is explanatory drawing of an example of the estimated atmospheric pressure adjustment map utilized with the engine control system which concerns on this Embodiment. 本実施の形態に係るエンジン制御システムにおける噴射量算出処理を説明するためのフロー図である。It is a flowchart for demonstrating the injection quantity calculation process in the engine control system which concerns on this Embodiment.
　以下、本実施の形態について添付図面を参照して詳細に説明する。なお、以下においては、本発明に係るエンジン制御システムが船外機に適用される場合について説明するが、その適用対象は船外機に限定されるものではなく適宜変更が可能である。例えば、吸気圧センサにより大気圧を推定する構成を有する自動二輪車等の車両にも適用することができる。また、本発明に係るエンジン制御システムは、バッテリを搭載しない船外機等に好適に使用されるが、バッテリを搭載する船外機等に適用しても構わない。 Hereinafter, the present embodiment will be described in detail with reference to the accompanying drawings. In the following, the case where the engine control system according to the present invention is applied to an outboard motor will be described. However, the application target is not limited to the outboard motor and can be appropriately changed. For example, the present invention can be applied to a vehicle such as a motorcycle having a configuration in which the atmospheric pressure is estimated by an intake pressure sensor. The engine control system according to the present invention is preferably used for an outboard motor or the like not equipped with a battery, but may be applied to an outboard motor or the like equipped with a battery.
　図１は、本実施の形態に係るエンジン制御システムの概略構成を示す図である。図２は、本実施の形態に係るエンジン制御システムが適用されるエンジンの吸気構造を示す模式図である。なお、図１においては、説明を簡素化するために本発明を適用する上で必要なエンジン及びＥＣＭ（Engine　Control　Module）周辺の構成要素のみを示し、それ以外の構成要素は省略している。本実施の形態に係るエンジン制御システムは、バッテリを搭載しない船外機等に適用される。 FIG. 1 is a diagram showing a schematic configuration of an engine control system according to the present embodiment. FIG. 2 is a schematic diagram showing an intake structure of an engine to which the engine control system according to the present embodiment is applied. In FIG. 1, only the components around the engine and ECM (Engine Control Module) necessary for applying the present invention are shown to simplify the description, and other components are omitted. The engine control system according to the present embodiment is applied to an outboard motor or the like not equipped with a battery.
　図１に示すように、エンジン制御システム１は、内燃機関であるエンジン２と、このエンジン２を制御するＥＣＭ３とを含んで構成される。エンジン２には、リコイルスタータ４及び発電機（ＡＣジェネレータ）５が設けられている。ＥＣＭ３には、エンジン回転数センサ６、吸気圧センサ７、スロットル開度センサ８及びインジェクタ９が接続されている。なお、エンジン回転数センサ６及び吸気圧センサ７は、それぞれ特許請求の範囲における回転数検出手段及び圧力検出手段を構成する。 1, the engine control system 1 includes an engine 2 that is an internal combustion engine and an ECM 3 that controls the engine 2. The engine 2 is provided with a recoil starter 4 and a generator (AC generator) 5. An engine speed sensor 6, an intake pressure sensor 7, a throttle opening sensor 8, and an injector 9 are connected to the ECM 3. The engine speed sensor 6 and the intake pressure sensor 7 constitute a speed detection means and a pressure detection means in the claims.
　エンジン２は、例えば、直動式のＤＯＨＣ（Double　OverHead　Camshaft）エンジンであり、クランク軸２１、シリンダ２２及びシリンダヘッド２３等を備えて構成される（図２参照）。シリンダ２２内には、ピストン２４が上下に往復可能に収容されている。クランク軸２１とピストン２４とはコンロッド２５によって連結されている。ピストン２４が上下方向に往復運動することで、クランク軸２１がコンロッド２５を介して回転される。 The engine 2 is, for example, a direct-acting DOHC (Double Overhead Camshaft) engine, and includes a crankshaft 21, a cylinder 22, a cylinder head 23, and the like (see FIG. 2). A piston 24 is accommodated in the cylinder 22 so as to reciprocate up and down. The crankshaft 21 and the piston 24 are connected by a connecting rod 25. As the piston 24 reciprocates in the vertical direction, the crankshaft 21 is rotated via the connecting rod 25.
　シリンダヘッド２３の内部には燃焼室２３１が設けられている。シリンダヘッド２３には、吸気ポート及び排気ポートに対応して、吸気バルブ２６及び排気バルブ２７が配設されている。これらの吸気バルブ２６及び排気バルブ２７に対応して一対のロッカーアーム２８ａ、２８ｂが設けられている。また、シリンダヘッド２３には、これらのロッカーアーム２８ａ、２８ｂを駆動するカムシャフト２９が設けられている。クランク軸２１及びカムシャフト２９には、不図示のカムチェーンが架け渡されており、クランク軸２１の回転は、このカムチェーンを介してカムシャフト２９に伝達される。 A combustion chamber 231 is provided inside the cylinder head 23. The cylinder head 23 is provided with an intake valve 26 and an exhaust valve 27 corresponding to the intake port and the exhaust port. A pair of rocker arms 28 a and 28 b are provided corresponding to the intake valve 26 and the exhaust valve 27. The cylinder head 23 is provided with a camshaft 29 that drives the rocker arms 28a and 28b. A cam chain (not shown) is bridged between the crankshaft 21 and the camshaft 29, and the rotation of the crankshaft 21 is transmitted to the camshaft 29 via the cam chain.
　カムシャフト２９が回転されることで、適時に一対のロッカーアーム２８ａ、２８ｂが駆動され、吸気バルブ２６及び排気バルブ２７が燃焼室２３１に向けて往復動される。このようにして、吸気バルブ２６及び排気バルブ２７のそれぞれにおける開閉タイミングが調整される。また、シリンダヘッド２３には、燃焼室２３１内の混合気に着火する点火装置３０（スパークプラグ）が設けられている。点火装置３０は、ＥＣＭ３から供給される点火信号に基づいて所定のタイミングで点火する。 When the camshaft 29 is rotated, the pair of rocker arms 28a and 28b are driven at an appropriate time, and the intake valve 26 and the exhaust valve 27 are reciprocated toward the combustion chamber 231. In this way, the opening / closing timing of each of the intake valve 26 and the exhaust valve 27 is adjusted. The cylinder head 23 is provided with an ignition device 30 (spark plug) that ignites the air-fuel mixture in the combustion chamber 231. The ignition device 30 ignites at a predetermined timing based on the ignition signal supplied from the ECM 3.
　リコイルスタータ４は、手動式始動装置として機能するものであり、エンジン２のクランク軸２１の一端に設けられている。リコイルスタータ４の内部には、図示しないプーリが収容されている。このプーリには、一端がリコイルスタータ４の筐体から露出した状態でロープ４１が巻き付けられている。このロープ４１の端部を操作者（運転者）が手で引くことによりエンジン２のクランク軸２１に回転力を与えることができる。 The recoil starter 4 functions as a manual starter and is provided at one end of the crankshaft 21 of the engine 2. A pulley (not shown) is accommodated inside the recoil starter 4. A rope 41 is wound around the pulley with one end exposed from the housing of the recoil starter 4. When the operator (driver) pulls the end of the rope 41 by hand, a rotational force can be applied to the crankshaft 21 of the engine 2.
　発電機５は、エンジン２のクランク軸２１におけるリコイルスタータ４の同一端に設けられている。例えば、発電機５は、交流マグネット発電機で構成される。交流マグネット発電機においては、クランク軸２１の他端に設けられた永久磁石と、この永久磁石に対向して配置された発電コイルとを含んで構成される。クランク軸２１の回転に伴って永久磁石が回転することにより、起電力が生じて発電コイルに発電される。 The generator 5 is provided at the same end of the recoil starter 4 in the crankshaft 21 of the engine 2. For example, the generator 5 is composed of an AC magnet generator. The AC magnet generator includes a permanent magnet provided at the other end of the crankshaft 21 and a power generation coil disposed to face the permanent magnet. When the permanent magnet rotates with the rotation of the crankshaft 21, an electromotive force is generated and the power generation coil generates power.
　ＥＣＭ３は、ＣＰＵ等の演算手段及びＲＡＭ、ＲＯＭ等の記憶手段を含んで構成される。ＥＣＭ３は、エンジン２の駆動に伴って発電機５に発生する発電電力で駆動される。例えば、ＥＣＭ３は、ＣＰＵがＲＯＭに記憶されたプログラムを実行することにより、大気圧推定部３１、大気圧記憶部３２及び燃料噴射量算出部３３として機能する。これらの構成要素の詳細については後述する。なお、大気圧推定部３１、大気圧記憶部３２及び燃料噴射量算出部３３は、それぞれ特許請求の範囲における大気圧推定手段、記憶手段及び燃料噴射量算出手段を構成する。 The ECM 3 includes a calculation unit such as a CPU and a storage unit such as a RAM and a ROM. The ECM 3 is driven by generated power generated in the generator 5 as the engine 2 is driven. For example, the ECM 3 functions as the atmospheric pressure estimation unit 31, the atmospheric pressure storage unit 32, and the fuel injection amount calculation unit 33 when the CPU executes a program stored in the ROM. Details of these components will be described later. Note that the atmospheric pressure estimation unit 31, the atmospheric pressure storage unit 32, and the fuel injection amount calculation unit 33 constitute an atmospheric pressure estimation unit, a storage unit, and a fuel injection amount calculation unit in the claims, respectively.
　エンジン回転数センサ６は、例えば、クランク軸２１と一体回転するクランクマグネト２１１の外周縁に対向して配置されている（図２参照）。クランクマグネト２１１は、概して円盤形状を有し、その外周面に複数の突起２１１ａが形成されている。エンジン回転数センサ６は、例えば、クランク軸２１の回転に伴って検出領域を通過する突起２１１ａの個数に基づいてエンジン回転数を検出する。エンジン回転数センサ６で検出されたエンジン回転数はＥＣＭ３（より具体的には、大気圧推定部３１及び燃料噴射量算出部３３）に出力される。 The engine speed sensor 6 is disposed, for example, facing the outer periphery of the crank magnet 211 that rotates integrally with the crankshaft 21 (see FIG. 2). The crank magneto 211 has a generally disk shape, and a plurality of protrusions 211a are formed on the outer peripheral surface thereof. The engine speed sensor 6 detects the engine speed based on, for example, the number of protrusions 211a that pass through the detection region as the crankshaft 21 rotates. The engine speed detected by the engine speed sensor 6 is output to the ECM 3 (more specifically, the atmospheric pressure estimation unit 31 and the fuel injection amount calculation unit 33).
　吸気圧センサ７は、吸気ポートに連結される吸気管２０１に配設されている（図２参照）。吸気管２０１には、スロットルバルブ１０が設けられている。吸気圧センサ７は、スロットルバルブ１０の下流側（図２に示す左方側）であって、吸気ポートとの間に位置する吸気管２０１に配置されており、吸気管２０１内の圧力（吸気管圧）を検出する。吸気圧センサ７で検出された吸気管圧はＥＣＭ３（より具体的には、大気圧推定部３１及び燃料噴射量算出部３３）に出力される。 The intake pressure sensor 7 is disposed in an intake pipe 201 connected to an intake port (see FIG. 2). The intake pipe 201 is provided with a throttle valve 10. The intake pressure sensor 7 is disposed on the intake pipe 201 located downstream of the throttle valve 10 (left side shown in FIG. 2) and between the intake port and the pressure in the intake pipe 201 (intake air). Tube pressure). The intake pipe pressure detected by the intake pressure sensor 7 is output to the ECM 3 (more specifically, the atmospheric pressure estimation unit 31 and the fuel injection amount calculation unit 33).
　スロットル開度センサ８は、例えば、吸気管２０１におけるスロットルバルブ１０に対応する位置に配設されている（図２参照）。スロットル開度センサ８は、スロットルバルブ１０の開度（スロットル開度）を検出する。スロットル開度センサ８で検出されたスロットル開度はＥＣＭ３に出力される。 The throttle opening sensor 8 is disposed, for example, at a position corresponding to the throttle valve 10 in the intake pipe 201 (see FIG. 2). The throttle opening sensor 8 detects the opening (throttle opening) of the throttle valve 10. The throttle opening detected by the throttle opening sensor 8 is output to the ECM 3.
　インジェクタ９は、電子式燃料噴射装置として機能するものであり、エンジン２の吸気管２０１に取り付けられている（図２参照）。インジェクタ９は、ＥＣＭ３からの駆動信号に応じて、図示しない燃料ポンプから供給される燃料を吸気管２０１内に噴射可能に構成されている。 The injector 9 functions as an electronic fuel injection device, and is attached to the intake pipe 201 of the engine 2 (see FIG. 2). The injector 9 is configured to be able to inject fuel supplied from a fuel pump (not shown) into the intake pipe 201 in response to a drive signal from the ECM 3.
　大気圧推定部３１は、吸気圧センサ７により検出された吸気管２０１の圧力（吸気管圧）から大気圧を推定する（推定大気圧）。より具体的には、大気圧推定部３１は、エンジン２の始動から一定時間内の最大吸気管圧を推定大気圧として推定する。大気圧推定部３１により推定された推定大気圧は、燃料噴射量算出部３３に出力される一方、後述する学習大気圧の更新条件を満たした場合に大気圧記憶部３２に出力される。 The atmospheric pressure estimation unit 31 estimates the atmospheric pressure from the pressure of the intake pipe 201 (intake pipe pressure) detected by the intake pressure sensor 7 (estimated atmospheric pressure). More specifically, the atmospheric pressure estimation unit 31 estimates the maximum intake pipe pressure within a predetermined time from the start of the engine 2 as the estimated atmospheric pressure. The estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 is output to the fuel injection amount calculation unit 33, and is output to the atmospheric pressure storage unit 32 when a learning atmospheric pressure update condition described later is satisfied.
　大気圧記憶部３２は、大気圧推定部３１から出力された推定大気圧を学習大気圧として記憶する。特に、大気圧記憶部３２は、エンジン２の停止後に推定大気圧を学習大気圧として記憶する。この学習大気圧は、次にエンジン２を始動した際の燃料噴射制御時に大気圧推定部３１により推定された推定大気圧との比較対象として利用される。大気圧記憶部３２を構成する記憶手段には、例えば、ＥＥＰＲＯＭ（Electrically　Erasable　Programmable　Read-Only　Memory）等の不揮発性メモリが好適に用いられる。大気圧記憶部３２をＥＥＰＲＯＭで実現することにより、エンジン停止後も推定大気圧（学習大気圧）を保存することができる。 The atmospheric pressure storage unit 32 stores the estimated atmospheric pressure output from the atmospheric pressure estimation unit 31 as a learning atmospheric pressure. In particular, the atmospheric pressure storage unit 32 stores the estimated atmospheric pressure as the learning atmospheric pressure after the engine 2 is stopped. This learned atmospheric pressure is used as a comparison object with the estimated atmospheric pressure estimated by the atmospheric pressure estimating unit 31 during the fuel injection control when the engine 2 is started next time. As the storage means constituting the atmospheric pressure storage unit 32, for example, a nonvolatile memory such as an EEPROM (Electrically Erasable Programmable Read-Only Memory) is preferably used. By realizing the atmospheric pressure storage unit 32 with an EEPROM, the estimated atmospheric pressure (learning atmospheric pressure) can be stored even after the engine is stopped.
　燃料噴射量算出部３３は、インジェクタ９による燃料噴射量を算出する。燃料噴射量算出部３３は、エンジン回転数センサ６で検出されたエンジン回転数と、大気圧推定部３１により推定された推定大気圧又は大気圧記憶部３２に記憶された学習大気圧とに基づいて燃料噴射量を算出する。より具体的にいうと、燃料噴射量算出部３３は、大気圧推定部３１により推定された推定大気圧と、大気圧記憶部３２に記憶された学習大気圧とを比較し、両者の差が予め定められた所定値より小さい場合には学習大気圧を利用して燃料噴射量を算出する一方、両者の差が所定値以の場合に吸気管圧に基づいて推定された推定大気圧を利用して燃料噴射量を算出する。 The fuel injection amount calculation unit 33 calculates the fuel injection amount by the injector 9. The fuel injection amount calculation unit 33 is based on the engine speed detected by the engine speed sensor 6 and the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 or the learned atmospheric pressure stored in the atmospheric pressure storage unit 32. To calculate the fuel injection amount. More specifically, the fuel injection amount calculation unit 33 compares the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 with the learning atmospheric pressure stored in the atmospheric pressure storage unit 32, and the difference between the two is determined. When less than a predetermined value, the learning atmospheric pressure is used to calculate the fuel injection amount. When the difference between the two is equal to or greater than the predetermined value, the estimated atmospheric pressure estimated based on the intake pipe pressure is used. Then, the fuel injection amount is calculated.
　また、燃料噴射量算出部３３は、一定条件を満たす場合に燃料噴射量の算出結果に応じて制御モード（非リーンバーン制御、リーンバーン制御）を変換する。詳細について後述するように、大気圧推定部３１により補正された推定大気圧と学習大気圧との差が一定値以下である場合に非リーンバーン制御モードからリーンバーン制御モードに移行し、このリーンバーン制御モードに適するように燃料噴射量を調整（算出）する。 Also, the fuel injection amount calculation unit 33 converts the control mode (non-lean burn control, lean burn control) according to the calculation result of the fuel injection amount when a certain condition is satisfied. As will be described in detail later, when the difference between the estimated atmospheric pressure corrected by the atmospheric pressure estimation unit 31 and the learning atmospheric pressure is equal to or less than a predetermined value, the non-lean burn control mode is shifted to the lean burn control mode, and this lean The fuel injection amount is adjusted (calculated) so as to be suitable for the burn control mode.
　このような構成を有し、本実施の形態に係るエンジン制御システム１においては、燃料噴射制御の際に大気圧推定部３１により推定された推定大気圧と、大気圧記憶部３２に記憶された学習大気圧とを比較する。そして、両者の比較結果に応じて推定大気圧又は学習大気圧を利用して燃料噴射量を算出することにより、スロットル開度の状況に関わらず適切に燃料噴射制御を行う。 In the engine control system 1 according to the present embodiment having such a configuration, the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 during the fuel injection control and the atmospheric pressure storage unit 32 are stored. Compare with the learning atmospheric pressure. Then, by calculating the fuel injection amount using the estimated atmospheric pressure or the learning atmospheric pressure according to the comparison result between them, the fuel injection control is appropriately performed regardless of the throttle opening degree.
　ここで、本実施の形態に係るエンジン制御システム１における燃料噴射制御時の動作について説明する。図３は、本実施の形態に係るエンジン制御システム１における燃料噴射制御時の動作概要を説明するためのフロー図である。 Here, the operation at the time of fuel injection control in the engine control system 1 according to the present embodiment will be described. FIG. 3 is a flowchart for explaining an outline of the operation at the time of fuel injection control in the engine control system 1 according to the present embodiment.
　本実施の形態に係るエンジン制御システム１においては、前回のエンジン停止時に記憶された学習大気圧を参照しながら燃料噴射制御を行う。このため、エンジン制御システム１の燃料噴射制御においては、図３に示すように、大気圧学習処理（ステップ（以下、「ＳＴ」という）３０１）、燃料噴射量算出処理（噴射量算出処理：ＳＴ３０２）及び燃料噴射処理（噴射処理：ＳＴ３０３）を含んで構成される。 In the engine control system 1 according to the present embodiment, fuel injection control is performed with reference to the learning atmospheric pressure stored when the engine was stopped last time. Therefore, in the fuel injection control of the engine control system 1, as shown in FIG. 3, atmospheric pressure learning processing (step (hereinafter referred to as “ST”) 301), fuel injection amount calculation processing (injection amount calculation processing: ST302). ) And fuel injection processing (injection processing: ST303).
　なお、図３においては、説明の便宜上、ＳＴ３０１に示す大気圧学習処理が実行された後にＳＴ３０２及びＳＴ３０３に示す噴射量算出処理及び噴射処理が実行される場合について説明している。しかしながら、実際には、ＳＴ３０２及びＳＴ３０３に示す噴射量算出処理及び噴射処理は、ＳＴ３０１に示す大気圧学習処理と並行して行われる。 For convenience of explanation, FIG. 3 illustrates a case where the injection amount calculation process and the injection process shown in ST302 and ST303 are executed after the atmospheric pressure learning process shown in ST301 is executed. However, in practice, the injection amount calculation process and the injection process shown in ST302 and ST303 are performed in parallel with the atmospheric pressure learning process shown in ST301.
　エンジン制御システム１においては、エンジン２が稼働している間、大気圧学習処理が実行される（ＳＴ３０１）。この大気圧学習処理は、燃料噴射制御時に参照される学習大気圧を学習する処理である。大気圧学習処理において、学習大気圧は、予め定められた更新条件を満たす場合に学習（更新）される。そして、エンジン２の停止時には、その時点での学習大気圧が大気圧記憶部３２に記憶される。 In the engine control system 1, the atmospheric pressure learning process is executed while the engine 2 is operating (ST301). This atmospheric pressure learning process is a process of learning a learning atmospheric pressure referred to during fuel injection control. In the atmospheric pressure learning process, the learning atmospheric pressure is learned (updated) when a predetermined update condition is satisfied. When the engine 2 is stopped, the learning atmospheric pressure at that time is stored in the atmospheric pressure storage unit 32.
　この大気圧学習処理に並行して噴射量算出処理が実行される（ＳＴ３０２）。この噴射量算出処理は、大気圧記憶部３２に記憶された学習大気圧と、大気圧推定部３１により推定された推定大気圧（吸気圧センサ７で検出された吸気管圧に基づく推定大気圧）との差に基づいてインジェクタ９による燃料噴射量を算出する処理である。 The injection amount calculation process is executed in parallel with this atmospheric pressure learning process (ST302). This injection amount calculation processing is performed by the learning atmospheric pressure stored in the atmospheric pressure storage unit 32 and the estimated atmospheric pressure estimated by the atmospheric pressure estimation unit 31 (the estimated atmospheric pressure based on the intake pipe pressure detected by the intake pressure sensor 7). This is a process for calculating the fuel injection amount by the injector 9 based on the difference from ().
　また、この噴射量算出処理においては、燃料噴射量の算出と共に制御モードの変換（移行）が判定され、その判定結果に応じて燃料噴射量が調整される。より具体的には、大気圧推定部３１により補正された推定大気圧と学習大気圧との差が一定値以下である場合に非リーンバーン制御モードからリーンバーン制御モードに変換され、このリーンバーン制御モードに適するように燃料噴射量を調整される。 Also, in this injection amount calculation process, the control mode conversion (transition) is determined together with the calculation of the fuel injection amount, and the fuel injection amount is adjusted according to the determination result. More specifically, when the difference between the estimated atmospheric pressure corrected by the atmospheric pressure estimation unit 31 and the learned atmospheric pressure is equal to or less than a certain value, the non-lean burn control mode is converted to the lean burn control mode, and this lean burn The fuel injection amount is adjusted to be suitable for the control mode.
　この噴射量算出処理により燃料噴射量が算出された後、噴射処理が実行される（ＳＴ３０３）。この噴射処理においては、噴射量算出処理で算出された燃料噴射量に基づいてインジェクタ９から燃料が噴射される。ＳＴ３０２及びＳＴ３０３に示す噴射量算出処理及び噴射処理は、エンジン２の稼働中に繰り返し実行される。 After the fuel injection amount is calculated by this injection amount calculation process, the injection process is executed (ST303). In this injection process, fuel is injected from the injector 9 based on the fuel injection amount calculated in the injection amount calculation process. The injection amount calculation process and the injection process shown in ST302 and ST303 are repeatedly executed while the engine 2 is operating.
　ここで、ＳＴ３０１に示す大気圧学習処理の詳細について説明する。図４は、本実施の形態に係るエンジン制御システム１における大気圧学習処理を説明するためのフロー図である。図４に示すように、大気圧学習処理においては、まず、吸気圧センサ７により吸気管２０１内の圧力（吸気管圧）が検出される（ＳＴ４０１）。検出された吸気管圧は、ＥＣＭ３の大気圧推定部３１に出力される。吸気圧センサ７から吸気管圧を受け取ると、大気圧推定部３１は、エンジン２の始動から一定時間内の最大吸気管圧を現在の大気圧として推定し、推定大気圧を得る（ＳＴ４０２）。 Here, the details of the atmospheric pressure learning process shown in ST301 will be described. FIG. 4 is a flowchart for explaining the atmospheric pressure learning process in the engine control system 1 according to the present embodiment. As shown in FIG. 4, in the atmospheric pressure learning process, first, the pressure in the intake pipe 201 (intake pipe pressure) is detected by the intake pressure sensor 7 (ST401). The detected intake pipe pressure is output to the atmospheric pressure estimation unit 31 of the ECM 3. When the intake pipe pressure is received from the intake pressure sensor 7, the atmospheric pressure estimation unit 31 estimates the maximum intake pipe pressure within a predetermined time from the start of the engine 2 as the current atmospheric pressure, and obtains the estimated atmospheric pressure (ST402).
　図４に示すＳＴ４０２にて、大気圧推定部３１により推定大気圧が推定されると、燃料噴射量算出部３３は、大気圧記憶部３２に記憶された学習大気圧（より具体的には、前回運転停止時に大気圧記憶部３２に記憶された学習大気圧）を読み込む（ＳＴ４０３）。そして、燃料噴射量算出部３３は、ＳＴ４０２により推定された推定大気圧と、前回運転停止時に記憶された学習大気圧との差が予め定めた大気圧更新判定値（以下、単に「判定値」という）以上であるかを判定する（ＳＴ４０４）。 When the estimated atmospheric pressure is estimated by the atmospheric pressure estimation unit 31 in ST402 shown in FIG. 4, the fuel injection amount calculation unit 33 reads the learning atmospheric pressure (more specifically, stored in the atmospheric pressure storage unit 32). The learning atmospheric pressure stored in the atmospheric pressure storage unit 32 when the previous operation was stopped is read (ST403). Then, the fuel injection amount calculation unit 33 determines an atmospheric pressure update determination value (hereinafter simply referred to as “determination value”) in which a difference between the estimated atmospheric pressure estimated in ST402 and the learned atmospheric pressure stored when the previous operation was stopped is predetermined. It is determined whether or not (ST404).
　ここで、推定大気圧と学習大気圧との差が予め定めた判定値以上である場合には、スロットル開度センサ８により一定時間継続してスロットル開度が全開状態（ＷＯＴ（Wide　Open　Throttle）状態）であるかが判定される（ＳＴ４０５）。ここで、一定時間ＷＯＴ状態が継続している場合には、学習大気圧の学習実行の有無を示すフラグ（以下、「学習実行フラグ」という）に「１」がセットされる（ＳＴ４０６）。学習実行フラグに「１」がセットされることで、ＳＴ４０２で推定された推定大気圧を利用した学習大気圧の学習（更新）が許容される。この場合、ＳＴ４０２で推定された推定大気圧が大気圧記憶部３２に書き込まれる。ＳＴ４０４及びＳＴ４０５は、学習大気圧の更新条件を判定する処理であり、いずれも肯定判定された場合に学習大気圧の更新条件が満たされる。なお、ＷＯＴ状態でない場合又は一定時間ＷＯＴ状態が継続していない場合には、ＳＴ４０５の判定が繰り返される。 Here, when the difference between the estimated atmospheric pressure and the learning atmospheric pressure is equal to or larger than a predetermined determination value, the throttle opening is continuously opened for a certain period of time by the throttle opening sensor 8 (WOT (Wide Open Throttle)). Is determined) (ST405). Here, when the WOT state continues for a certain period of time, “1” is set to a flag (hereinafter referred to as “learning execution flag”) indicating whether or not learning atmospheric pressure is executed (ST406). By setting “1” to the learning execution flag, learning (updating) of the learning atmospheric pressure using the estimated atmospheric pressure estimated in ST402 is permitted. In this case, the estimated atmospheric pressure estimated in ST402 is written in the atmospheric pressure storage unit 32. ST404 and ST405 are processes for determining a learning atmospheric pressure update condition. If both are positively determined, the learning atmospheric pressure update condition is satisfied. In addition, when it is not a WOT state or when the WOT state is not continued for a certain time, the determination of ST405 is repeated.
　このようにＳＴ４０５の判定を繰り返す際、大気圧推定部３１において、エンジン回転数に応じて推定大気圧を調整することは実施の形態として好ましい。この場合、大気圧推定部３１は、例えば、図５に示す推定大気圧調整マップに基づいて推定大気圧を調整することができる。図５は、本実施の形態に係るエンジン制御システム１で利用される推定大気圧調整マップの一例の説明図である。 As described above, when the determination of ST405 is repeated, it is preferable as an embodiment that the atmospheric pressure estimation unit 31 adjust the estimated atmospheric pressure according to the engine speed. In this case, the atmospheric pressure estimation unit 31 can adjust the estimated atmospheric pressure based on, for example, the estimated atmospheric pressure adjustment map shown in FIG. FIG. 5 is an explanatory diagram of an example of an estimated atmospheric pressure adjustment map used in the engine control system 1 according to the present embodiment.
　図５に示すように、推定大気圧調整マップにおいては、縦軸に吸気圧センサ７による検出値Ｐｂが対応づけられ、横軸にエンジン回転数センサ６によるエンジン回転数Ｎｅが対応づけられている。大気圧推定部３１は、吸気圧センサ７から吸気管圧を受け取ると、図５に示す推定大気圧調整マップに基づいて、エンジン回転数センサ６から受け取ったエンジン回転数に応じてこれを調整することができる。 As shown in FIG. 5, in the estimated atmospheric pressure adjustment map, the detected value Pb from the intake pressure sensor 7 is associated with the vertical axis, and the engine rotational speed Ne with the engine rotational speed sensor 6 is associated with the horizontal axis. . Upon receiving the intake pipe pressure from the intake pressure sensor 7, the atmospheric pressure estimation unit 31 adjusts it according to the engine speed received from the engine speed sensor 6 based on the estimated atmospheric pressure adjustment map shown in FIG. be able to.
　例えば、吸気圧センサ７から吸気管圧として「７０ｋＰａ」を受け取った場合において、エンジン回転数センサ６から受け取ったエンジン回転数が「２５００ｒ／ｍｉｎ」である場合、大気圧推定部３１は、推定大気圧を「６８ｋＰａ」に調整することができる（図５に示すＰｂ３、Ｎｅ２参照）。また、吸気圧センサ７から吸気管圧として「８０ｋＰａ」を受け取った場合において、エンジン回転数センサ６から受け取ったエンジン回転数が「５０００ｒ／ｍｉｎ」である場合、大気圧推定部３１は、推定大気圧を「８３ｋＰａ」に調整することができる（図５に示すＰｂ５、Ｎｅ７参照）。 For example, when “70 kPa” is received as the intake pipe pressure from the intake pressure sensor 7, and the engine speed received from the engine speed sensor 6 is “2500 r / min”, the atmospheric pressure estimation unit 31 calculates the estimated high pressure. The atmospheric pressure can be adjusted to “68 kPa” (see Pb3 and Ne2 shown in FIG. 5). Further, when “80 kPa” is received as the intake pipe pressure from the intake pressure sensor 7, when the engine speed received from the engine speed sensor 6 is “5000 r / min”, the atmospheric pressure estimation unit 31 estimates the estimated high pressure. The atmospheric pressure can be adjusted to “83 kPa” (see Pb5 and Ne7 shown in FIG. 5).
　このように推定大気圧と前記学習大気圧との差が所定値以上の場合、大気圧推定部３１がエンジン回転数に応じて推定大気圧を調整することにより、エンジン回転数に応じて変動する吸気管圧に追随して推定大気圧を調整することができる。これにより、エンジン回転数に応じて変動する吸気管圧に追随してより正確且つ広範な範囲で推定大気圧を得ることが可能となる。 As described above, when the difference between the estimated atmospheric pressure and the learned atmospheric pressure is equal to or greater than a predetermined value, the atmospheric pressure estimating unit 31 adjusts the estimated atmospheric pressure according to the engine speed, and thus varies according to the engine speed. The estimated atmospheric pressure can be adjusted following the intake pipe pressure. As a result, it is possible to obtain the estimated atmospheric pressure in a more accurate and wide range following the intake pipe pressure which varies depending on the engine speed.
　ＳＴ４０６にて学習実行フラグに「１」がセットされた後、大気圧推定部３１は、推定大気圧の補正処理（推定大気圧補正処理）を行う（ＳＴ４０７）。この推定大気圧補正処理においては、予め定められた大気圧学習フィルタ値及び学習大気圧に基づいて推定大気圧（ＳＴ４０２で推定された推定大気圧）が補正される。例えば、推定大気圧補正処理により補正される補正推定大気圧Ｘは、以下の（式１）に基づいて演算される。ここで「Ｆ１」は、大気圧学習フィルタ値を指す。
　Ｘ＝　Ｆ１　×　学習大気圧　＋　（１－Ｆ１）　×　推定大気圧　　　　（式１） After “1” is set to the learning execution flag in ST406, the atmospheric pressure estimation unit 31 performs a process for correcting the estimated atmospheric pressure (estimated atmospheric pressure correction process) (ST407). In this estimated atmospheric pressure correction process, the estimated atmospheric pressure (estimated atmospheric pressure estimated in ST402) is corrected based on the predetermined atmospheric pressure learning filter value and the learned atmospheric pressure. For example, the corrected estimated atmospheric pressure X corrected by the estimated atmospheric pressure correction process is calculated based on the following (Equation 1). Here, “F1” indicates an atmospheric pressure learning filter value.
X = F1 × learning atmospheric pressure + (1-F1) × estimated atmospheric pressure (Formula 1)
　この推定大気圧補正処理が行われた後、燃料噴射量算出部３３は、補正後の推定大気圧（補正推定大気圧）と、吸気管圧から推定された現在の推定大気圧との差が判定値以下であるか否かを判定する（ＳＴ４０８）。なお、補正推定大気圧と現在の推定大気圧との差が判定値以下でない場合、処理がＳＴ４０５に戻され、再びＳＴ４０５～ＳＴ４０８の処理が行われる。 After this estimated atmospheric pressure correction process is performed, the fuel injection amount calculation unit 33 calculates the difference between the corrected estimated atmospheric pressure (corrected estimated atmospheric pressure) and the current estimated atmospheric pressure estimated from the intake pipe pressure. It is determined whether or not it is equal to or less than a determination value (ST408). If the difference between the corrected estimated atmospheric pressure and the current estimated atmospheric pressure is not less than the determination value, the process returns to ST405, and the processes of ST405 to ST408 are performed again.
　これに対し、補正推定大気圧と現在の推定大気圧との差が判定値以下である場合には、リーンバーン制御モードへの変換の許否を示すフラグ（以下、「モード変換フラグ」という）に「１」がセットされる（ＳＴ４０９）。このようにモード変換フラグに「１」がセットされることで、非リーンバーン制御モードからリーンバーン制御モードへの変換が許容される。すなわち、補正推定大気圧と現在の推定大気圧との差が判定値以下の場合に限ってリーンバーン制御モードへの移行が許容されている。 On the other hand, when the difference between the corrected estimated atmospheric pressure and the current estimated atmospheric pressure is equal to or smaller than the determination value, a flag indicating whether or not conversion to the lean burn control mode is permitted (hereinafter referred to as “mode conversion flag”) is performed. “1” is set (ST409). Thus, when the mode conversion flag is set to “1”, conversion from the non-lean burn control mode to the lean burn control mode is permitted. That is, the transition to the lean burn control mode is allowed only when the difference between the corrected estimated atmospheric pressure and the current estimated atmospheric pressure is equal to or smaller than the determination value.
　そして、モード変換フラグに「１」がセットされた後、イグニッションスイッチがオン状態（電源オン）に維持されているかが判定される（ＳＴ４１０）。オン状態に維持されている場合には、処理がＳＴ４０１に戻され、再びＳＴ４０１～ＳＴ４１０の処理が行われる。すなわち、電源オン状態が維持される場合には、吸気圧センサ７で検出された吸気管圧に基づく推定大気圧と学習大気圧とが比較され、その比較結果に応じて学習大気圧が学習されていく。一方、イグニッションスイッチがオフ状態に切り替えられている場合には、その直前にＳＴ４０２で推定された推定大気圧が学習大気圧として再度大気圧記憶部３２に書き込まれ、学習大気圧が更新される（ＳＴ４１１）。 Then, after “1” is set in the mode conversion flag, it is determined whether or not the ignition switch is kept on (power on) (ST410). If it is kept on, the process returns to ST401, and the processes of ST401 to ST410 are performed again. That is, when the power-on state is maintained, the estimated atmospheric pressure based on the intake pipe pressure detected by the intake pressure sensor 7 is compared with the learning atmospheric pressure, and the learning atmospheric pressure is learned according to the comparison result. To go. On the other hand, when the ignition switch is switched to the OFF state, the estimated atmospheric pressure estimated in ST402 immediately before that is written as the learning atmospheric pressure in the atmospheric pressure storage unit 32 again, and the learning atmospheric pressure is updated ( ST411).
　一方、ＳＴ４０４の判定において、推定大気圧と学習大気圧との差が判定値（大気圧更新判定値）より小さい場合、ＳＴ４０９以降の処理が行われる。すなわち、ＳＴ４０９にてモード変換フラグに「１」がセットされた後、ＳＴ４１０にてイグニッションスイッチのオン状態が判定され、オフ状態である場合には、ＳＴ４１１にて学習大気圧が更新される。このような一連の処理を経てＳＴ４１１にて大気圧学習値が更新された後、大気圧学習処理が終了する。 On the other hand, if the difference between the estimated atmospheric pressure and the learned atmospheric pressure is smaller than the determination value (atmospheric pressure update determination value) in the determination of ST404, the processing after ST409 is performed. That is, after the mode conversion flag is set to “1” in ST409, the ON state of the ignition switch is determined in ST410. If the ignition switch is in the OFF state, the learning atmospheric pressure is updated in ST411. After the atmospheric pressure learning value is updated in ST411 through such a series of processes, the atmospheric pressure learning process ends.
　次に、ＳＴ３０２に示す噴射量算出処理について説明する。図６は、本実施の形態に係るエンジン制御システムにおける噴射量算出処理を説明するためのフロー図である。図６に示すように、噴射量算出処理においては、まず、吸気圧センサ７により吸気管２０１内の圧力（吸気管圧）が検出される（ＳＴ６０１）。検出された吸気管圧は、ＥＣＭ３の大気圧推定部３１に出力される。吸気圧センサ７から吸気管圧を受け取ると、大気圧推定部３１は、エンジン２の始動から一定時間内の最大吸気管圧を現在の大気圧として推定し、推定大気圧を得る（ＳＴ６０２）。 Next, the injection amount calculation process shown in ST302 will be described. FIG. 6 is a flowchart for explaining an injection amount calculation process in the engine control system according to the present embodiment. As shown in FIG. 6, in the injection amount calculation process, first, the pressure in the intake pipe 201 (intake pipe pressure) is detected by the intake pressure sensor 7 (ST601). The detected intake pipe pressure is output to the atmospheric pressure estimation unit 31 of the ECM 3. When the intake pipe pressure is received from the intake pressure sensor 7, the atmospheric pressure estimation unit 31 estimates the maximum intake pipe pressure within a predetermined time from the start of the engine 2 as the current atmospheric pressure, and obtains the estimated atmospheric pressure (ST602).
　大気圧推定部３１により推定大気圧が推定されると、燃料噴射量算出部３３は、大気圧記憶部３２に記憶された学習大気圧を読み込む（ＳＴ６０３）。そして、燃料噴射量算出部３３は、ＳＴ４０２により推定された推定大気圧と学習大気圧との差が判定値（大気圧更新判定値）以上であるかを判定する（ＳＴ６０４）。 When the estimated atmospheric pressure is estimated by the atmospheric pressure estimation unit 31, the fuel injection amount calculation unit 33 reads the learning atmospheric pressure stored in the atmospheric pressure storage unit 32 (ST603). Then, the fuel injection amount calculation unit 33 determines whether the difference between the estimated atmospheric pressure estimated in ST402 and the learned atmospheric pressure is equal to or greater than a determination value (atmospheric pressure update determination value) (ST604).
　ここで、大気圧学習値と検出吸気圧との差が判定値以上である場合、燃料噴射量算出部３３は、ＳＴ６０２で推定された推定大気圧を利用して燃料噴射量を算出する（ＳＴ６０５）。一方、大気圧学習値と検出吸気圧との差が判定値より小さい場合、燃料噴射量算出部３３は、大気圧記憶部３２に記憶された学習大気圧を利用して燃料噴射量を算出する（ＳＴ６０６）。 Here, when the difference between the atmospheric pressure learning value and the detected intake pressure is greater than or equal to the determination value, the fuel injection amount calculation unit 33 calculates the fuel injection amount using the estimated atmospheric pressure estimated in ST602 (ST605). ). On the other hand, when the difference between the atmospheric pressure learning value and the detected intake pressure is smaller than the determination value, the fuel injection amount calculation unit 33 calculates the fuel injection amount using the learning atmospheric pressure stored in the atmospheric pressure storage unit 32. (ST606).
　ＳＴ６０６で学習大気圧を利用して燃料噴射量を算出した後、燃料噴射量算出部３３は、モード変換フラグに「１」がセットされているか否かを判定する（ＳＴ６０７）。この判定は、非リーンバーン制御モードからリーンバーン制御モードへの移行が許容されているかを判定するものである。 After calculating the fuel injection amount using the learning atmospheric pressure in ST606, the fuel injection amount calculation unit 33 determines whether “1” is set in the mode conversion flag (ST607). This determination is to determine whether the transition from the non-lean burn control mode to the lean burn control mode is permitted.
　ここで、モード変換フラグに「１」がセットされている場合、燃料噴射量算出部３３は、ＳＴ６０６で算出した燃料噴射量をリーンバーン制御モードに適した燃料噴射量に調整する（ＳＴ６０８）。すなわち、非リーンバーン制御モードによる理想的な空燃比よりも燃料比率が低い空燃比となるように燃料噴射量を調整する。一方、モード変換フラグに「０」がセットされている場合には、燃料噴射量算出部３３は、ＳＴ６０８をスキップし、リーンバーン制御モードに適した燃料噴射量に調整することはない。 Here, when “1” is set in the mode conversion flag, the fuel injection amount calculation unit 33 adjusts the fuel injection amount calculated in ST606 to a fuel injection amount suitable for the lean burn control mode (ST608). That is, the fuel injection amount is adjusted so that the air-fuel ratio is lower than the ideal air-fuel ratio in the non-lean burn control mode. On the other hand, when “0” is set in the mode conversion flag, the fuel injection amount calculation unit 33 skips ST608 and does not adjust to the fuel injection amount suitable for the lean burn control mode.
　このようにＳＴ６０５又はＳＴ６０６にて燃料噴射量を算出し、或いは、ＳＴ６０８にて燃料噴射量を調整すると、噴射量算出処理が終了する。そして、この噴射量算出処理にて算出（調整）された燃料噴射量は、図３のＳＴ３０３に示す噴射処理で利用され、当該燃料噴射量に応じた燃料がインジェクタ９から吸気管２０１に噴射される。これにより、吸気管圧に基づく推定大気圧又は大気圧記憶部３２に記憶された学習大気圧のいずれかに基づいて算出された燃料噴射量が噴射されることとなる。 As described above, when the fuel injection amount is calculated in ST605 or ST606, or the fuel injection amount is adjusted in ST608, the injection amount calculation process is completed. The fuel injection amount calculated (adjusted) in this injection amount calculation processing is used in the injection processing shown in ST303 in FIG. 3, and fuel corresponding to the fuel injection amount is injected from the injector 9 into the intake pipe 201. The As a result, the fuel injection amount calculated based on either the estimated atmospheric pressure based on the intake pipe pressure or the learned atmospheric pressure stored in the atmospheric pressure storage unit 32 is injected.
　以上説明したように、本実施の形態に係るエンジン制御システム１によれば、エンジン始動の際に推定された推定大気圧と、大気圧記憶部３２に記憶された学習大気圧とを比較し、両者の差が所定値（判定値）より小さい場合に学習大気圧を利用して燃料噴射量が算出される一方、両者の差が所定値（判定値）以上の場合に吸気管圧から推定される推定大気圧を利用して燃料噴射量が算出される。このため、例えば、スロットル開度が全開付近に至らない場合であっても、記憶された学習大気圧を利用して燃料量を算出することができる。この結果、スロットル開度の状況に関わらず適切に燃料噴射制御を行うことが可能となる。 As described above, according to the engine control system 1 according to the present embodiment, the estimated atmospheric pressure estimated when the engine is started is compared with the learned atmospheric pressure stored in the atmospheric pressure storage unit 32. When the difference between the two is smaller than a predetermined value (determination value), the fuel injection amount is calculated using the learning atmospheric pressure, whereas when the difference between the two is equal to or larger than the predetermined value (determination value), the fuel injection amount is estimated from the intake pipe pressure. The fuel injection amount is calculated using the estimated atmospheric pressure. For this reason, for example, even when the throttle opening does not reach the fully open position, the fuel amount can be calculated using the stored learning atmospheric pressure. As a result, fuel injection control can be performed appropriately regardless of the throttle opening situation.
　また、本実施の形態に係るエンジン制御システム１においては、燃料噴射量算出部３３により、推定大気圧と学習大気圧との差が所定値（判定値）以下の場合に非リーンバーン制御からリーンバーン制御に適した燃料噴射量を算出する。これにより、推定大気圧と学習大気圧との差が所定値以下の場合に限ってリーンバーン制御に適した燃料噴射量が算出されることから、急激にエンジン出力が低下することを回避しつつリーンバーン運転を実現することができる。 Further, in the engine control system 1 according to the present embodiment, the fuel injection amount calculation unit 33 performs the lean control from the non-lean burn control when the difference between the estimated atmospheric pressure and the learning atmospheric pressure is a predetermined value (determination value) or less. A fuel injection amount suitable for burn control is calculated. As a result, the fuel injection amount suitable for lean burn control is calculated only when the difference between the estimated atmospheric pressure and the learning atmospheric pressure is equal to or less than a predetermined value, so that a sudden decrease in engine output is avoided. Lean burn operation can be realized.
　なお、本発明は上記各実施の形態に限定されず、種々変更して実施することが可能である。上記実施の形態において、添付図面に図示されている回路構成や制御フローなどについては、これに限定されず、本発明の効果を発揮する範囲内で適宜変更することが可能である。その他、本発明の目的の範囲を逸脱しない限りにおいて適宜変更して実施することが可能である。 It should be noted that the present invention is not limited to the above embodiments, and can be implemented with various modifications. In the above embodiment, the circuit configuration, control flow, and the like illustrated in the accompanying drawings are not limited to this, and can be appropriately changed within the scope of the effects of the present invention. In addition, various modifications can be made without departing from the scope of the object of the present invention.
　例えば、上記実施の形態においては、エンジン停止時には大気圧記憶部３２にて必ず学習大気圧を更新する場合について説明しているが、学習大気圧を必ず更新するタイミングについては、エンジン停止時に限定されるものではなく適宜変更が可能である。例えば、緊急停止スイッチが操作者（運転者）により操作された場合（すなわち、緊急停止スイッチがオン状態とされた場合）に学習大気圧を更新するようにしてもよい。 For example, in the above-described embodiment, the case where the learning atmospheric pressure is always updated in the atmospheric pressure storage unit 32 when the engine is stopped has been described. However, the timing for always updating the learning atmospheric pressure is limited to when the engine is stopped. It is not a thing and it can change suitably. For example, the learning atmospheric pressure may be updated when the emergency stop switch is operated by an operator (driver) (that is, when the emergency stop switch is turned on).
　以上説明したように、本発明は、スロットル開度の状況に関わらず適切に燃料噴射制御を行うことができるという効果を有し、特に、バッテリを備えず、発電機による発電電力で燃料噴射量を調整する燃料噴射装置を駆動するエンジンを搭載した船外機や自動二輪車等の車両に有用である。 As described above, the present invention has an effect that the fuel injection control can be appropriately performed regardless of the throttle opening state, and in particular, the fuel injection amount is not provided with the battery but is generated by the power generated by the generator. It is useful for vehicles such as outboard motors and motorcycles equipped with an engine that drives a fuel injection device that adjusts fuel consumption.
　本出願は、２０１４年３月２７日出願の特願２０１４－０６６４９０に基づく。この内容は、全てここに含めておく。 This application is based on Japanese Patent Application No. 2014-066490 filed on March 27, 2014. All this content is included here.

Claims (3)

  1. 　エンジン回転数を検出する回転数検出手段と、スロットルバルブの下流の吸気管圧を検出する圧力検出手段と、前記圧力検出手段により検出された吸気管圧から推定大気圧を推定する大気圧推定手段と、前記大気圧推定手段から出力された推定大気圧を学習大気圧としてエンジン停止後に記憶する記憶手段と、エンジン回転数及び前記推定大気圧に基づいて燃料噴射量を算出する燃料噴射量算出手段と、を備え、
    　前記燃料噴射量算出手段は、エンジン始動の際に推定された前記推定大気圧と前記記憶手段に記憶された前記学習大気圧とを比較し、前記推定大気圧と前記学習大気圧との差が所定値より小さい場合に当該学習大気圧を利用して燃料噴射量を算出する一方、前記推定大気圧と前記学習大気圧との差が所定値以上の場合に当該推定大気圧を利用して燃料噴射量を算出することを特徴とするエンジン制御システム。     An engine speed detecting means for detecting the engine speed, a pressure detecting means for detecting an intake pipe pressure downstream of the throttle valve, and an atmospheric pressure estimating means for estimating an estimated atmospheric pressure from the intake pipe pressure detected by the pressure detecting means. Storage means for storing the estimated atmospheric pressure output from the atmospheric pressure estimating means as a learning atmospheric pressure after the engine is stopped, and a fuel injection amount calculating means for calculating the fuel injection amount based on the engine speed and the estimated atmospheric pressure And comprising
    The fuel injection amount calculating means compares the estimated atmospheric pressure estimated at the time of engine start with the learned atmospheric pressure stored in the storage means, and the difference between the estimated atmospheric pressure and the learned atmospheric pressure is When the difference between the estimated atmospheric pressure and the learned atmospheric pressure is greater than or equal to a predetermined value, the fuel injection amount is calculated using the learned atmospheric pressure when the fuel pressure is smaller than a predetermined value. An engine control system for calculating an injection amount.
  2. 　前記推定大気圧と前記学習大気圧との差が所定値以上の場合、前記大気圧推定手段は、エンジン回転数に応じて前記推定大気圧を調整することを特徴とする請求項１記載のエンジン制御システム。 2. The engine according to claim 1, wherein when the difference between the estimated atmospheric pressure and the learned atmospheric pressure is equal to or greater than a predetermined value, the atmospheric pressure estimating means adjusts the estimated atmospheric pressure according to an engine speed. Control system.
  3. 　前記燃料噴射量算出手段は、前記推定大気圧と前記学習大気圧との差が所定値以下の場合に非リーンバーン制御からリーンバーン制御に適した燃料噴射量を算出することを特徴とする請求項１又は請求項２記載のエンジン制御システム。 The fuel injection amount calculation means calculates a fuel injection amount suitable for lean burn control from non-lean burn control when the difference between the estimated atmospheric pressure and the learned atmospheric pressure is a predetermined value or less. The engine control system according to claim 1 or 2.
PCT/JP2015/054366 2014-03-27 2015-02-18 Engine control system WO2015146379A1 (en)

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JPH11280528A (en) * 1998-03-30 1999-10-12 Unisia Jecs Corp Diagnostic device for assist air supply device
JP2004036462A (en) * 2002-07-02 2004-02-05 Toyota Motor Corp Control device for internal combustion engine
JP2011106315A (en) * 2009-11-16 2011-06-02 Toyota Motor Corp Failure detection device and brake device
JP2013194532A (en) * 2012-03-16 2013-09-30 Hitachi Automotive Systems Ltd Control device of engine
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JP6323112B2 (en) 2018-05-16
JP2015190339A (en) 2015-11-02
EP2963272A1 (en) 2016-01-06
EP2963272A4 (en) 2016-11-02

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