Vehicle control device

Abstract

To properly estimate the internal pressure of an intake manifold to accurately calculate the amount of intake air for each cylinder when starting an internal combustion engine in response to a start request made during operation stop processing.SOLUTION: A vehicle control device according to the present disclosure: calculates a moving average value of an actual internal pressure of an intake manifold of an internal combustion engine; based on the difference between the current moving average value and the moving average value calculated at a time point that is before the present time by a predetermined interval, calculates an amount of change in the internal pressure of the intake manifold per a predetermined crank angle; and when starting the internal combustion engine in response to a start request made during operation stop processing, calculates an internal pressure estimation value of the intake manifold at intake valve closing timing of a next injection cylinder by adding an estimated change portion, which is determined from a crank angle width from the current crank angle to the intake valve closing timing based on the compression top dead center of the next injection cylinder into which fuel is injected next, and the amount of change in the above internal pressure.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present disclosure relates to a control device for a vehicle equipped with an internal combustion engine that includes an intake manifold and a plurality of cylinders, each having an intake valve. [Background technology]

[0002] Conventionally, there is known a control device for an internal combustion engine that calculates the intake air amount of the internal combustion engine from the intake manifold pressure, which is the actual internal pressure of the intake manifold, every time the intake manifold pressure is read from the detection signal of the intake air pressure sensor after the internal combustion engine is started (for example, see Patent Document 1). This control device calculates the intake air amount of the internal combustion engine (each cylinder) from the intake manifold pressure until time T1 has elapsed from the start of the internal combustion engine, and estimates the intake air amount of the internal combustion engine by Kalman filter calculation from the intake air amount of the internal combustion engine detected by the intake air amount sensor after time T1+T2 has elapsed from the start of the internal combustion engine. In addition, during the period from time T1 after the start of the internal combustion engine until time T1+T2 has elapsed, the intake air amount for control is calculated by linearly interpolating the intake air amount calculated from the intake manifold pressure and the intake air amount estimated by the Kalman filter calculation. This makes it possible to make the intake air amount for control suitable for the control of the internal combustion engine. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2018-173067 A Summary of the Invention [Problem to be solved by the invention]

[0004] In a vehicle in which an internal combustion engine is stopped intermittently, the internal combustion engine may be started (restarted) in response to the driver's depression of the accelerator pedal due to a so-called change of mind immediately after the start of an internal combustion engine operation stop process. When the internal combustion engine starts to start due to such a change of mind, the throttle valve is closed until just before the start, so the intake manifold pressure is reduced. Furthermore, the intake valve is closed and ignition is performed with a delay after the fuel injection amount is calculated in response to an engine start request. For this reason, when the fuel injection amount is calculated, the intake air amount calculated from the intake manifold pressure at that time (current) does not correspond to the actual situation, and if the fuel injection amount is calculated based on the intake air amount, the air-fuel ratio becomes lean, which deteriorates combustion, and the engine to be started may stall.

[0005] Therefore, the main objective of the present disclosure is to be able to properly estimate the internal pressure of the intake manifold and accurately calculate the intake air volume of each cylinder when starting an internal combustion engine in response to a start-up request made during operation stop processing. [Means for solving the problem]

[0006] The vehicle control device disclosed herein is a control device for a vehicle equipped with an internal combustion engine including a plurality of cylinders and an intake manifold, each having an intake valve, and includes a moving average value calculation unit that calculates a moving average value of the actual internal pressure of the intake manifold, a change amount calculation unit that calculates a change amount of the internal pressure of the intake manifold per specified crank angle based on the difference between the current moving average value and the moving average value calculated at a point in time a specified interval prior to the present, and an internal pressure estimation unit that, when starting the internal combustion engine in response to a start request made during the operation stop processing of the internal combustion engine, adds an estimated fluctuation amount determined from the crank angle width from the current crank angle based on the compression top dead center of the next injection cylinder into which fuel is next injected to the intake valve closing timing of the next injection cylinder and the change amount of the internal pressure calculated by the change amount calculation unit to calculate an estimated internal pressure value of the intake manifold at the intake valve closing timing of the next injection cylinder.

[0007] The control device of the vehicle disclosed herein calculates a moving average value of the actual internal pressure of the intake manifold, and calculates the amount of change in the internal pressure of the intake manifold per predetermined crank angle based on the difference between the current moving average value and the moving average value calculated at a time point a predetermined interval before the current time. Furthermore, when starting the internal combustion engine in response to a start request made during the operation stop process, the control device adds an estimated fluctuation determined from the crank angle width from the current crank angle based on the compression top dead center of the next injection cylinder into which fuel is next injected to the intake valve closing timing of the next injection cylinder and the amount of change in the internal pressure per predetermined crank angle to the current moving average value, thereby calculating an estimated value of the internal pressure of the intake manifold at the intake valve closing timing of the next injection cylinder. As a result, even if the internal pressure of the intake manifold has decreased and the intake air amount in the intake manifold has become fluctuating when a start request is made during the operation stop process of the internal combustion engine, the internal pressure of the intake manifold at the intake valve closing timing that determines the intake air amount of the next injection cylinder can be appropriately estimated. As a result, when starting the internal combustion engine in response to a start request made during the operation stop process, it is possible to accurately calculate the intake air volume for each cylinder of the internal combustion engine based on the estimated internal pressure value of the intake manifold.

[0008] Furthermore, when the intake valve closing timing of the next injection cylinder arrives, the control device may hold the internal pressure estimated value for the next injection cylinder at the value calculated by the internal pressure estimator at the intake valve closing timing, and change the next injection cylinder to a next cylinder. This makes it possible to more appropriately execute fuel injection control, etc., for a cylinder with a closed intake valve while the intake valve is closed.

[0009] Furthermore, the moving average value calculation unit may acquire the actual internal pressure and calculate the average value of the most recent multiple actual internal pressures as the moving average value each time the crankshaft of the internal combustion engine rotates a predetermined angle, the change amount calculation unit may calculate the change amount based on the difference between the current moving average value and the moving average value calculated at a point in time the top dead center interval of the internal combustion engine from the present each time the crankshaft rotates a predetermined angle, and the internal pressure estimation unit may calculate the internal pressure estimated value each time the crankshaft rotates a predetermined angle when starting the internal combustion engine in response to a start request made during the operation stop processing.

[0010] The vehicle may be a hybrid vehicle equipped with an electric motor capable of outputting power for running. [Brief description of the drawings]

[0011] [Figure 1] 1 is a schematic configuration diagram showing a vehicle controlled by a control device of the present disclosure. [Diagram 2] 2 is a schematic diagram showing the configuration of an internal combustion engine mounted on the vehicle of FIG. 1. [Diagram 3] 4 is a flowchart showing a routine executed by the control device of the present disclosure to estimate the internal pressure of the intake manifold when a start request is made during processing to stop the operation of the internal combustion engine. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0012] Next, an embodiment of the present disclosure will be described with reference to the drawings.

[0013] 1 is a schematic diagram showing a hybrid vehicle 1 as a vehicle controlled by a control device of the present disclosure. The hybrid vehicle 1 shown in the figure includes an engine (internal combustion engine) 10, a motor generator MG, a power transmission device 30, and a hydraulic clutch K0. The hybrid vehicle 1 further includes a high-voltage battery (high-voltage electricity storage device) 40, a low-voltage battery (low-voltage electricity storage device) 50 as an auxiliary battery, a power control device (hereinafter referred to as "PCU") 60 that drives the motor generator MG, a motor electronic control unit (hereinafter referred to as "MGECU") 70 that controls the PCU 60, and an electronic control unit (hereinafter referred to as "main ECU") 80 as a control device of the present disclosure that controls the engine 10 and the power transmission device 30.

[0014] As shown in FIG. 2, engine 10 is a multi-cylinder gasoline engine (e.g., a V-type 6-cylinder engine) that converts the reciprocating motion of pistons 13, which accompanies the combustion of a mixture of hydrocarbon fuel and air in multiple combustion chambers (cylinders) 12 formed in engine block 11, into the rotational motion of a crankshaft (output shaft) 14. In addition to engine block 11, multiple combustion chambers 12, pistons 13, and crankshaft 14, engine 10 includes an air cleaner 15, an intake pipe 16, an electronically controlled throttle valve 17, an intake manifold 18 having a surge tank and multiple intake ports, multiple intake valves 19i that open and close the corresponding intake ports, exhaust valves 19e that open and close the corresponding exhaust ports, multiple port injection valves 20p that inject fuel into the corresponding intake ports, multiple in-cylinder injection valves 20d that directly inject fuel into the corresponding combustion chambers 12, multiple ignition plugs 21, and an exhaust pipe 22 that forms an exhaust passage.

[0015] The engine 10 also includes an upstream purification device 23 and a downstream purification device 24, each of which is incorporated in the exhaust pipe 22, as exhaust gas purification devices. The upstream purification device 23 includes a NOx storage type exhaust gas purification catalyst (three-way catalyst) that purifies harmful components such as CO (carbon monoxide), HC, and NOx in the exhaust gas from each combustion chamber 12 of the engine 10. The downstream purification device 24 includes a particulate filter (GPF) that collects particulate matter (fine particles) in the exhaust gas, and is disposed downstream of the upstream purification device 23. In this embodiment, the particulate filter is a porous filter that supports a NOx storage type exhaust gas purification catalyst (three-way catalyst). That is, the downstream purification device 24 is configured as a four-way catalyst that has the purification function of a three-way catalyst and the collection function of particulate matter.

[0016] Furthermore, the engine 10 includes a coolant circulation passage 25 for cooling the engine block 11 etc., an electric pump 26, and a radiator 27. The electric pump 26 circulates coolant (LLC) through the coolant circulation passage 25. The radiator 27 cools the coolant that has absorbed heat from the engine block 11 etc. by heat exchange with air from traveling wind or an electric fan (not shown). A water temperature sensor 25t is also provided in the coolant circulation passage 25. The water temperature sensor 25t detects the water temperature Tw of the coolant that has absorbed heat from (flowed out of) the engine block 11.

[0017] In addition, the engine 10 includes a supercharger 28 that compresses intake air by utilizing the energy of exhaust gas, and a liquid-cooled intercooler 29 that cools the air compressed by the supercharger 28. The supercharger 28 is a turbocharger, and includes a turbine wheel 28t, a compressor wheel 28c, a turbine shaft 28s that integrally connects the turbine wheel 28t and the compressor wheel 28c, a wastegate valve 28w, and a blow-off valve 28b, as shown in FIG. 2. The turbine wheel 28t is rotatably disposed in a turbine housing formed in the exhaust pipe 22 so as to be located upstream of the upstream purification device 23. The compressor wheel 28c is rotatably disposed in a compressor housing formed in the intake pipe 16 so as to be located between the air cleaner 15 and the throttle valve 17.

[0018] 1, the engine 10 also includes a starter (engine starting device) ST that is used to crank the engine 10 mainly in an extremely low temperature environment, and an alternator A that is driven by the engine 10 to generate electric power. Furthermore, a crankshaft 14 of the engine 10 is connected to an input member of a damper mechanism D (e.g., a flywheel damper).

[0019] The motor generator MG is a synchronous generator motor (three-phase AC motor) including a rotor with a permanent magnet embedded therein and a stator around which a three-phase coil is wound, and exchanges electric power with the high-voltage battery 40 via the PCU 60. The motor generator MG operates as an electric motor that is driven by electric power from the high-voltage battery 40 to generate drive torque, and outputs regenerative braking torque when braking the hybrid vehicle 1. The motor generator MG also operates as a generator that generates electric power using at least a portion of the power from the engine 10 that is operated under load. As shown in FIG. 1, the rotor of the motor generator MG is fixed to a transmission shaft TS.

[0020] The power transmission device 30 includes a torque converter (fluid transmission) 31 having a torque amplification function, a lock-up clutch 32, a mechanical oil pump 33, an electric oil pump 34, a transmission (automatic transmission) 35, a hydraulic control device 36 that adjusts the pressure of hydraulic oil, etc. The torque converter 31 includes a pump impeller connected to the transmission shaft TS via a front cover (input member), a turbine runner connected to an input shaft 35i of the transmission 35, and a stator that amplifies the torque by rectifying the flow of hydraulic oil from the turbine runner to the pump impeller. The lock-up clutch 32 is a multiple-plate or single-plate friction hydraulic clutch that connects the front cover and the input shaft 35i of the transmission 35 and releases the connection between them.

[0021] The transmission 35 is, for example, a 4-10 speed type multi-speed transmission including an input shaft 35i, an output shaft 35o, a plurality of planetary gears, and a plurality of clutches and brakes (engagement elements for gear shifting). The transmission 35 changes the speed of the power transmitted from the transmission shaft TS to the input shaft 35i via either the torque converter 31 or the lock-up clutch 32 in a plurality of stages, and outputs the power from the output shaft 35o to the left and right wheels (drive wheels) W via the differential gear DF ​​and the drive shaft DS. The hydraulic control device 36 includes a valve body in which a plurality of oil passages are formed, a plurality of regulator valves, a plurality of linear solenoid valves, and the like. The hydraulic control device 36 adjusts the pressure of the hydraulic oil (hydraulic pressure) from at least one of the mechanical oil pump 33 and the electric oil pump 34, and supplies it to the torque converter 31, the lock-up clutch 32, the clutches and brakes of the transmission 35, and the like.

[0022] The clutch K0 connects and disconnects the output member of the damper mechanism D, i.e., the crankshaft 14 of the engine 10, to the transmission shaft TS, i.e., the rotor of the motor generator MG, in response to the hydraulic pressure supplied from the hydraulic control device 36. In this embodiment, the clutch K0 is a normally open hydraulic clutch that is released as the engagement hydraulic pressure supplied from the hydraulic control device 36 decreases and is engaged as the engagement hydraulic pressure increases. When the clutch K0 is engaged, the engine 10 (crankshaft 14) is connected to the motor generator MG via the clutch K0. As a result, the engine 10 is connected to the left and right wheels W via the damper mechanism D, the clutch K0, the transmission shaft TS (motor generator MG), the power transmission device 30, and the like. The clutch K0 may be disposed inside the rotor of the motor generator MG, or may be disposed axially between the damper mechanism D and the motor generator MG.

[0023] The high-voltage battery 40 is, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery having a rated output voltage of about 200-300 V. However, the high-voltage battery 40 may be a capacitor, or may include both a secondary battery and a capacitor. The low-voltage battery 50 is, for example, a lead-acid battery having a rated output voltage of 12 V, and is charged by power from the alternator A. The low-voltage battery 50 supplies power to auxiliary equipment such as the starter ST of the engine 10, the electric oil pump 34, and the hydraulic control device 36, and electronic devices such as various ECUs.

[0024] The PCU 60 includes an inverter that drives the motor generator MG, a boost converter, a DC / DC converter, etc. (none of which are shown), and is connected to the high-voltage battery 40 and the low-voltage battery 50 via a system main relay SMR. The inverter includes, for example, six transistors as switching elements and six diodes connected in parallel in the reverse direction to these transistors. The boost converter boosts the voltage from the high-voltage battery 40 and supplies it to the inverter, and also reduces the voltage from the inverter and supplies it to the high-voltage battery 40. The DC / DC converter reduces the power from the high-voltage battery 40 or the inverter and supplies it to a low-voltage system, i.e., the low-voltage battery 50 and various auxiliaries.

[0025] The MGECU 70 includes a microcomputer having a CPU, ROM, RAM, input / output interface, etc. (not shown), various drive circuits, various logic ICs, etc., and is connected to the main ECU 80 via a shared communication line and a dedicated communication line. The MGECU 70 acquires command values ​​from the main ECU 80, pre-boost voltages and post-boost voltages of the boost converter, the rotational position of the rotor of the motor generator MG, i.e., the transmission shaft TS, detected by a rotational position sensor (resolver) (not shown), and a phase current applied to the motor generator MG. The MGECU 70 controls the switching of the inverter and the boost converter based on this information. In addition, the MGECU 70 calculates the rotation speed Nm (rpm) of the rotor (transmission shaft TS) of the motor generator MG based on the detection value of the rotational position sensor at predetermined time intervals (for example, several msec), and calculates the angular velocity ωm and angular acceleration αm of the rotor.

[0026] The main ECU 80 includes a microcomputer having a CPU, ROM, RAM, input / output interfaces, etc. (not shown), various drive circuits, various logic ICs, etc. The main ECU 80 acquires a signal from a start switch (IG switch), an accelerator opening Acc (amount of depression of the accelerator pedal) detected by an accelerator pedal position sensor (not shown), a vehicle speed V detected by a vehicle speed sensor (not shown), a gear ratio γ of the transmission 35 corresponding to the accelerator opening Acc and the vehicle speed V, a rotation speed Nm of the motor generator MG from the MGECU 70, etc.

[0027] 1, the crank angle sensor 14a, the air flow meter 16a, the pressure sensor 16p and the temperature sensor 16t provided upstream of the compressor wheel 28c of the intake pipe 16, the boost pressure sensor 16c, the throttle opening sensor 17o, the intake pressure sensor 18p and the temperature sensor 18t provided in the intake manifold 18 (surge tank), the upstream air-fuel ratio sensor 22f, the downstream air-fuel ratio sensor 22r, the exhaust gas temperature sensor 22t, the water temperature sensor 25t, and an outside air temperature sensor and an atmospheric pressure sensor (not shown). Furthermore, the main ECU 80 obtains the SOC, the target charge / discharge power Pb*, the allowable charge power Win, the allowable discharge power Wout, and the like of the high-voltage battery 40 calculated by a power management device (power management ECU) (not shown) connected via a shared communication line and a dedicated communication line. Based on this information, the main ECU 80 controls the engine 10, the power transmission device 30, and the clutch K0 (hydraulic control device 36), and sets a torque command value Tm* to the motor generator MG.

[0028] In the hybrid vehicle 1 configured as described above, when the system is stopped and the mechanical oil pump 33 and the electric oil pump 34 are not generating oil pressure (parked), the normally open clutch K0 is released, thereby disconnecting the engine 10 from the transmission shaft TS, i.e., the motor generator MG. After the system is started, the hybrid vehicle 1 basically starts moving using torque (power) from the motor generator MG that is output to the power transmission device 30 as the drive system via the transmission shaft TS with the clutch K0 released.

[0029] After the system of the hybrid vehicle 1 is started, the main ECU 80 derives a required torque Tr* (including a required braking torque) to be output to the output shaft 35o of the transmission 35 corresponding to the accelerator opening Acc and the vehicle speed V, and sets a required running power Pd* required for running the hybrid vehicle 1 based on the required torque Tr* and the rotation speed of the output shaft 35o. When the operation of the engine 10 is stopped, the main ECU 80 sets the target power Pe*, target rotation speed Ne*, and target torque Te* of the engine 10 to "0", and sets a torque command value Tm* within the range of the allowable charging power Win and the allowable discharging power Wout so that a torque corresponding to the required torque Tr* is output from the motor generator MG to the output shaft 35o. The torque command value Tm* is transmitted from the main ECU 80 to the MGECU 70, and the MGECU 70 controls the switching of the inverter and the boost converter of the PCU 60 based on the torque command value Tm*.

[0030] Furthermore, while the hybrid vehicle 1 is stopped (including parked) or traveling by power from the motor generator MG, the main ECU 80 judges whether or not predetermined engine start conditions related to the required torque Tr*, the required running power Pd*, the target charge / discharge power Pb* of the high-voltage battery 40, the allowable discharge power Wout, and the like are satisfied. When the main ECU 80 judges that the engine start conditions are satisfied, it executes a start process in a manner corresponding to the traveling state of the hybrid vehicle 1 to start the engine 10 and engage the clutch K0. When the start process of the engine 10 is completed and the clutch K0 is fully engaged, the main ECU 80 sets the target power Pe*, the target rotation speed Ne*, and the target torque Te* of the engine 10 based on the required running power Pd*, the target charge / discharge power Pb* of the high-voltage battery 40, and the like so that the engine 10 is operated efficiently. Furthermore, the main ECU 80 sets a torque command value Tm* to the motor generator MG according to the required torque Tr*, and the like within the range of the allowable charge power Win and the allowable discharge power Wout. This allows the engine 10 to be operated at an operating point near the optimum fuel economy line, while the high-voltage battery 40 is charged with electric power generated by the motor generator MG according to the SOC of the high-voltage battery 40, and the motor generator MG is driven with electric power from the high-voltage battery 40 to output torque from both the engine 10 and the motor generator MG to the wheels W. Therefore, in the hybrid vehicle 1, it is possible to ensure good power performance while improving the fuel economy of the engine 10.

[0031] During operation of the engine 10, the main ECU 80 determines whether or not a predetermined engine stop condition is satisfied in relation to the vehicle speed V, the required torque Tr*, the required running power Pd*, the target charge / discharge power Pb*, the allowable discharge power Wout, and the like. When the main ECU 80 determines that the engine stop condition is satisfied, it executes a process for stopping the operation of the engine 10 and releases the clutch K0. This makes it possible to intermittently stop the engine 10 according to the state of the hybrid vehicle 1, thereby improving the fuel efficiency of the engine 10 and further improving the energy efficiency of the hybrid vehicle 1. Furthermore, when an engine start condition is satisfied after the operation of the engine 10 is stopped in response to the satisfaction of the engine stop condition, the engine 10 is started again.

[0032] Incidentally, in the hybrid vehicle 1 in which the engine 10 is stopped intermittently, the engine start condition may be satisfied in response to the driver's depression of the accelerator pedal due to a so-called change of mind immediately after the engine 10 operation stop processing is started in response to the engine stop condition being satisfied, and the engine 10 may be started (restarted). For example, when the start condition is satisfied immediately after the engine 10 operation stop processing is started and the engine speed Ne of the engine 10 is equal to or higher than a predetermined speed (for example, 400-500 rpm), in order to shorten the start time and smoothly increase the engine speed Ne, the engine 10 is started by injecting fuel into each combustion chamber 12 from the in-cylinder injection valve 20d at least once (at least the last time in the case of split injection) in the compression stroke with the clutch K0 released, and by burning a rich mixture (stratified combustion) in the vicinity of the spark plug 21. At this time, the amount of intake air in each combustion chamber 12 is determined based on the actual internal pressure P of the intake manifold 18 (surge tank) detected by the intake pressure sensor 18p. IN However, when the engine 10 is started due to a change of mind, the actual internal pressure P INThe intake air amount in the intake manifold 18 becomes fluctuating and the intake pulsation becomes irregular. As a result, the actual internal pressure P IN Therefore, the actual internal pressure P IN Therefore, there is a risk that the amount of intake air for each combustion chamber 12 cannot be calculated with high accuracy.

[0033] In consideration of this, in the hybrid vehicle 1, when a start request is made in response to the establishment of an engine start condition during the operation stop processing of the engine 10, in order to estimate the internal pressure of the intake manifold 18 with higher accuracy, the main ECU 80 executes a routine shown in FIG. 3. The routine shown in FIG. 3 is executed by the main ECU 80 every time the crankshaft 14 rotates by 30° (a predetermined angle) during the period from when a start request is made in response to the establishment of an engine start condition during the operation stop processing of the engine 10 until the start processing is completed. More specifically, the main ECU 80 increments a 30CA counter every time the crankshaft 14 rotates by 30° based on the output value of the crank angle sensor 14a, and resets the 30CA counter once when the crankshaft 14 rotates by 720°, and then resumes counting up the 30CA counter. The main ECU 80 executes the routine shown in FIG. 3 at the timing when the 30CA counter is incremented or reset.

[0034] When starting the routine of FIG. 3, the main ECU 80 receives the crank angle θ calculated based on the output value of the crank angle sensor 14a, the actual internal pressure P of the intake manifold 18 detected by the intake pressure sensor 18p, and INThen, information necessary for estimating the internal pressure of the intake manifold 18, such as the number of the next injection cylinder, which is the combustion chamber 12 into which fuel is injected next, is acquired (step S100). Here, the next injection cylinder is basically the combustion chamber 12 into which the piston 13 next reaches the compression top dead center at the timing when the routine of FIG. 3 is executed, and is determined from the crank angle θ at the time when the engine 10 was last stopped and the fuel injection sequence in the engine 10 (for example, the sequence of #1, #2, #3, #4, #5, #6). That is, when the routine of FIG. 3 is first executed in response to a start request, the combustion chamber 12 into which the piston 13 reaches the compression top dead center first or second after that time point is separately specified as the next injection cylinder based on the crank angle θ at the time when the engine 10 was last stopped. Thereafter, the next injection cylinder is changed over time in accordance with the fuel injection sequence (for example, the sequence of #1, #2, #3, #4, #5, #6).

[0035] After the process of step S100, the main ECU 80 calculates a current crank angle θ based on the compression top dead center of the next injection cylinder on the basis of the crank angle θ acquired in step S100. BTDC That is, the crank angle before the top dead center of the compression stroke of the next injection cylinder is acquired (step S110). BTDC is the crank angle θ at the intake valve closing timing (IVC) of the next injection cylinder. IVC In this embodiment, the crank angle θ of the intake valve closing timing of the next injection cylinder when the engine 10 is restarted is determined (step S120). IVC is a constant value determined a predetermined angle (for example, about 10°) before the compression top dead center.

[0036] Current crank angle θ BTDC is the crank angle θ of the intake valve closing timing of the next injection cylinder IVC If it is determined that the actual internal pressure P IN Moving average value of P AVE That is, the actual internal pressure P INIn step S130, the moving average value P AVE is the actual internal pressure P for the number of times (here, the most recent four times) obtained by dividing the top dead center interval of the engine 10 (120° in the case of a six-cylinder engine) by the angle (30°) corresponding to the execution period of the routine of FIG. IN The main ECU 80 detects the actual internal pressure P detected by the intake pressure sensor 18p not only when a start request is made during the process of stopping the engine 10, but also at least while the crankshaft 14 is rotating, every time the crankshaft 14 rotates by 30°. IN Get the moving average value P AVE Calculate the moving average value P AVE After calculating the moving average value P AVE In order to calculate the actual internal pressure P IN (current value) is stored in the RAM, and the actual internal pressure P obtained three cycles ago is IN (the value before last) is erased from the RAM (step S140). As a result, when the process of step S140 is executed, the RAM of the main ECU 80 stores the actual internal pressure P IN will be stored (memorized).

[0037] Next, the main ECU 80 calculates the amount of change ΔP of the internal pressure of the intake manifold 18 per one crank angle (1°) (step S150). In step S150, the main ECU 80 calculates the current moving average value P AVE The moving average value P calculated at a point before the top dead center interval (predetermined interval) of the engine 10 AVE The main ECU 80 calculates the amount of change ΔP of the internal pressure of the intake manifold 18 per one crank angle (predetermined crank angle) by dividing the value obtained by subtracting the current moving average value P AVE and the current crank angle θ BTDC and the crank angle θ at the intake valve closing timing of the next injection cylinder. IVC The crank angle width (θ BTDC -θ IVC) and the amount of change ΔP calculated in step S150, the estimated internal pressure P of the intake manifold 18 is calculated. INest In step S160, the main ECU 80 calculates the current moving average value P AVE , the difference (θ BTDC -θ IVC ), the estimated fluctuation (=(θ BTDC -θ IVC )·ΔP·d) to obtain the estimated internal pressure P INest Calculate.

[0038] On the other hand, in step S120, the current crank angle θ BTDC is the crank angle θ of the intake valve closing timing of the next injection cylinder IVC If it is determined that the intake valve 19i of the next injection cylinder, i.e., the combustion chamber 12 having the number acquired in step S100, is closed at the intake valve closing timing, and the main ECU 80 determines the internal pressure estimated value P INest 3 is held at the value (previous value) at the previous execution time of the routine of Fig. 3, i.e., the value calculated at the intake valve closing timing (step S170). Furthermore, the main ECU 80 changes the number of the next injection cylinder in accordance with the fuel injection sequence in the engine 10 (step S180), and temporarily ends the routine of Fig. 3. As a result, after the processing of steps S170 and S180 is executed, the next injection cylinder is changed to the next combustion chamber 12 determined by the fuel injection sequence, for example, from cylinder #1 to cylinder #2, and the estimated internal pressure P INest In addition, for the combustion chamber 12 that is no longer the next injection cylinder due to the closing of the intake valve 19i, the internal pressure estimated value P INest is held at the value calculated at the intake valve closing timing (previous value).

[0039] As described above, the main ECU 80 as the vehicle control device of the present disclosure detects the actual internal pressure P IN Moving average value of P AVE a moving average value calculation unit (steps S130, S140) that calculates the change amount ΔP of the internal pressure of the intake manifold 18 per one crank angle (predetermined crank angle) (step S150); and an estimated internal pressure P of the intake manifold 18 at the intake valve closing timing of the next injection cylinder into which fuel is next injected when starting the engine 10 in response to a start request made during the operation stop process. INest More specifically, the main ECU 80 functions as an internal pressure estimation unit (step S160) that calculates the actual internal pressure P IN The average value of the most recent multiple times is the moving average value P AVE In addition, the main ECU 80 as a change amount calculation unit calculates the current moving average value P AVE and a moving average value P calculated at a point before the current time by the interval (predetermined interval) between the top dead center of the engine 10. AVE Furthermore, when starting the engine 10 in response to a start request made during the operation stop process, the main ECU 80 as the internal pressure estimating section estimates the current moving average value P AVE The current crank angle θ based on the compression top dead center of the next injection cylinder BTDC Crank angle width (θ BTDC -θ IVC ) and the estimated fluctuation determined from the amount of change in internal pressure ΔP per crank angle, to obtain the estimated internal pressure P of the intake manifold 18 at the intake valve closing timing of the next injection cylinder. INest Calculate.

[0040] As a result, when a start request is made during the engine 10 operation stop process, the actual internal pressure P INEven if the intake air amount in the intake manifold 18 becomes fluctuating or the intake pulsation varies, the internal pressure of the intake manifold 18 at the intake valve closing timing that determines the intake air amount of the next injection cylinder can be properly estimated. As a result, when starting the engine 10 in response to a start request made during the operation stop process, the intake air amount of each combustion chamber 12 of the engine 10 can be accurately calculated. Therefore, when restarting the engine 10, the fuel injection amount can be calculated based on the accurately calculated intake air amount, so that it is possible to effectively prevent the engine 10 from stalling due to the air-fuel ratio in the combustion chamber 12 becoming lean and combustion deteriorating.

[0041] In addition, when the intake valve closing timing of the next injection cylinder arrives, the main ECU 80 calculates the internal pressure estimated value P INest is held at the value calculated at the intake valve closing timing (step S170), and the next injection cylinder is changed to the next cylinder (step S180). This makes it possible to more appropriately execute fuel injection control while the intake valve 19i is closed for the combustion chamber 12 in which the intake valve 19i is closed.

[0042] The engine 10 of the hybrid vehicle 1 may be a diesel engine, an LPG engine, a biofuel engine, or the like. The hybrid vehicle 1 may be a four-wheel drive vehicle including a transfer that can distribute and transmit torque from the output shaft 35o of the transmission 35 to the differential gear DF ​​and another differential gear. The transmission 35 may be a mechanical continuously variable transmission, a dual clutch transmission, or the like. A clutch that connects and disconnects the rotor of the motor generator MG and the transmission shaft TS may be disposed between them (see the two-dot chain line in FIG. 1). The alternator A may be omitted from the hybrid vehicle 1. The functions of the main ECU 80 may be distributed to a plurality of electronic control devices, such as an engine ECU and a transmission ECU. The vehicle to which the control device of the present disclosure is applied is not limited to a hybrid vehicle, but may be a vehicle that includes only an engine as a power generation source for running and in which so-called idle stop control is executed.

[0043] The present disclosure is not limited to the above embodiment, and various modifications can be made within the scope of the present disclosure. Furthermore, the above embodiment is merely a specific form of the invention described in the Summary of the Invention, and does not limit the elements of the invention described in the Summary of the Invention. [Industrial Applicability]

[0044] The present disclosure is applicable to the internal combustion engine and vehicle manufacturing industries, etc. [Explanation of symbols]

[0045] 1 hybrid vehicle, 10 engine, 12 combustion chamber (cylinder), 14 crankshaft, 14a crank angle sensor, 18 intake manifold, 18p intake pressure sensor, 19i intake valve, 20d in-cylinder injection valve, 20p port injection valve, 21 spark plug, 30 power transmission device, 40 high voltage battery, 50 low voltage battery, 70 motor electronic control unit (MGECU), 80 electronic control unit (main ECU), MG motor generator.

Claims

1. A control device for a vehicle equipped with an internal combustion engine including a plurality of cylinders and an intake manifold, each having an intake valve, comprising: a moving average value calculation unit that calculates a moving average value of the actual internal pressure of the intake manifold; a change amount calculation unit that calculates a change amount of the internal pressure of the intake manifold per predetermined crank angle based on a difference between the current moving average value and the moving average value calculated at a point in time a predetermined interval before the present; an internal pressure estimation unit that, when starting the internal combustion engine in response to a start request made during processing for stopping the operation of the internal combustion engine, calculates an estimated internal pressure value of the intake manifold at the intake valve closing timing of the next injection cylinder by adding, to the current moving average value calculated by the moving average value calculation unit, an estimated fluctuation amount determined from a crank angle width from a current crank angle based on a compression top dead center of a next injection cylinder into which fuel is next injected to the intake valve closing timing of the next injection cylinder and an amount of change in the internal pressure calculated by the change amount calculation unit; A vehicle control device comprising:

2. 2. The vehicle control device according to claim 1, A vehicle control device that, when the intake valve closing timing for the next injection cylinder arrives, holds the internal pressure estimated value for the next injection cylinder at the value calculated by the internal pressure estimation unit at the intake valve closing timing, and changes the next injection cylinder to the next cylinder.

Images