JP6477564B2 - Engine equipment - Google Patents

Description

  The present invention relates to an engine device, and more particularly to an engine device including an engine having a variable valve timing mechanism capable of changing an opening / closing timing of an intake valve.

  Conventionally, as this type of engine device, one having an engine having a variable valve timing mechanism capable of changing the opening / closing timing of an intake valve has been proposed (for example, see Patent Document 1). In this engine apparatus, when the engine stop request is made, the fuel injection of the engine is stopped while the opening / closing timing of the intake valve is delayed to the latest timing.

JP 2012-31742 A

  In the engine device described above, when the opening / closing timing of the intake valve is delayed to a latest timing in a relatively short time when the engine stop request is made, the engine fuel injection (engine fuel injection) is performed. Before the engine is stopped), the intake air amount of the engine may become relatively small, and the engine may be misfired below the lower limit air amount necessary for combustion.

  The engine device of the present invention is mainly intended to suppress the occurrence of misfire in the engine.

  The engine device of the present invention employs the following means in order to achieve the main object described above.

The engine device of the present invention is
An engine having a variable valve timing mechanism capable of changing the opening and closing timing of the intake valve;
Control means for controlling the engine to stop fuel injection of the engine while delaying the opening and closing timing to a predetermined timing when the engine stop request is made;
An engine device comprising:
When the engine stop request is made and the engine load is equal to or higher than the predetermined load, the control means immediately sets the predetermined timing as a target timing, and when the engine load is lower than the predetermined load, The target timing is set so as to be gradually delayed toward the predetermined timing, and the variable valve timing mechanism is controlled using the target timing.
This is the gist.

  In the engine device of the present invention, when the engine stop request is made, the engine is controlled so as to stop the fuel injection of the engine while delaying the opening / closing timing of the intake valve to a predetermined timing. Furthermore, when an engine stop request is made, if the engine load is equal to or higher than the predetermined load, the predetermined timing is immediately set as the target timing, and if the engine load is less than the predetermined load, the engine is gradually delayed toward the predetermined timing. The target timing is set so that the variable valve timing mechanism is controlled using the target timing. As a result, when the engine load is less than the predetermined load, the intake air amount of the engine is relatively small compared to the case where the predetermined timing is set as the target timing, and the engine air pressure is below the lower limit air amount necessary for combustion. Can be suppressed. As a result, it is possible to suppress the occurrence of misfire in the engine. Of course, when the engine load is equal to or higher than the predetermined load, the opening / closing timing of the intake valve can be quickly delayed to the predetermined timing. At this time, since the intake air amount of the engine is relatively large, it is unlikely that the intake air amount of the engine will fall below the lower limit air amount necessary for combustion even if the opening / closing timing of the intake valve is quickly delayed to a predetermined timing. Conceivable.

  In such an engine device of the present invention, the control means may be means for setting the predetermined timing to the target timing when fuel injection of the engine is stopped after the engine stop request is made. Good. In this way, the opening / closing timing of the intake valve can be quickly delayed to a predetermined timing.

1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 including an engine device 21 as an embodiment of the present invention. It is a flowchart which shows an example of the control routine performed by engine ECU24 of an Example. FIG. 6 is an explanatory diagram showing an example of a state when the phase angle θvvt of the variable valve timing mechanism 23 is delayed in response to a request to stop the engine 22 when the load on the engine 22 is relatively small.

  Next, the form for implementing this invention is demonstrated using an Example.

  FIG. 1 is a configuration diagram showing an outline of a configuration of a hybrid vehicle 20 including an engine device 21 as an embodiment of the present invention. The hybrid vehicle 20 of the embodiment includes an engine 22, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery 50, and a hybrid electronic control unit (hereinafter referred to as HVECU) 70, as shown. .

  The engine 22 is configured as an internal combustion engine that outputs power using gasoline or light oil as a fuel. The engine 22 includes a variable valve timing mechanism 23 that can be driven by a motor (not shown) to continuously change the opening / closing timing VT of the intake valve. Operation of the engine 22 is controlled by an engine electronic control unit (hereinafter referred to as engine ECU) 24.

  Although not shown, the engine ECU 24 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The engine ECU 24 includes signals from various sensors necessary for controlling the operation of the engine 22, for example, a crank angle θcr from the crank position sensor 22a that detects the rotational position of the crankshaft 26, and an intake camshaft that opens and closes the intake valve. The cam angle θci from the cam position sensor 22b that detects the rotational position of the air, the intake air amount Qa from the air flow meter 22c, and the like are input via the input port. From the engine ECU 24, various control signals for controlling the operation of the engine 22, for example, control signals to the variable valve timing mechanism 23 are output via an output port. The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr. Further, the engine ECU 24 calculates the intake valve opening / closing timing VT based on the angle (θci−θcr) of the intake camshaft cam angle θci from the cam position sensor 22b with respect to the crank angle θcr from the crank position sensor 22a. Yes. Hereinafter, the angle (θci−θcr) is referred to as a phase angle θvvt. In the embodiment, the smaller the phase angle θvvt, the slower the opening / closing timing VT of the intake valve. Further, the engine ECU 24 determines the volumetric efficiency (the amount of air actually sucked in one cycle with respect to the stroke volume per cycle of the engine 22) based on the intake air amount Qa from the air flow meter 22 c and the rotational speed Ne of the engine 22. Volume ratio) KL is calculated. In the embodiment, the volumetric efficiency KL is used as the load of the engine 22.

  The planetary gear 30 is configured as a single pinion type planetary gear mechanism. The sun gear of planetary gear 30 is connected to the rotor of motor MG1. The ring gear of the planetary gear 30 is connected to a drive shaft 36 that is coupled to the drive wheels 38 a and 38 b via a differential gear 37. A crankshaft 26 of the engine 22 is connected to the carrier of the planetary gear 30.

  The motor MG1 is configured as a synchronous generator motor, for example, and the rotor is connected to the sun gear of the planetary gear 30 as described above. The motor MG2 is configured as, for example, a synchronous generator motor, and a rotor is connected to the drive shaft 36. The motors MG1 and MG2 are rotationally driven by switching control of switching elements (not shown) of the inverters 41 and 42 by a motor electronic control unit (hereinafter referred to as motor ECU) 40.

  Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . Signals from various sensors necessary for driving and controlling the motors MG1, MG2 are input to the motor ECU 40 via the input port. The motor ECU 40 receives the rotational positions θm1 and θm2 from the rotational position detection sensors 43 and 44 that detect the rotational positions of the rotors of the motors MG1 and MG2 via the input port.

  From the motor ECU 40, switching control signals to a plurality of switching elements (not shown) of the inverters 41 and 42 are output via an output port. The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 controls driving of the motors MG1 and MG2 by a control signal from the HVECU 70 and outputs data related to the driving state of the motors MG1 and MG2 to the HVECU 70 as necessary. The motor ECU 40 calculates the rotational speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position detection sensors 43, 44.

  The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel hydride secondary battery, and exchanges electric power with the motors MG1 and MG2 via the inverters 41 and 42. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as a battery ECU) 52.

  Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. . The battery ECU 52 includes a battery voltage Vb from a voltage sensor that detects a voltage between terminals of the battery 50, a battery current Ib from a current sensor that detects a current between terminals of the battery 50, and a temperature sensor that detects the temperature of the battery 50. The battery temperature Tb is input via the input port. The battery ECU 52 is connected to the HVECU 70 via a communication port, and outputs data relating to the state of the battery 50 to the HVECU 70 as necessary. In order to manage the battery 50, the battery ECU 52 calculates the storage ratio SOC based on the integrated value of the battery current Ib, and calculates the input / output limits Win and Wout based on the calculated storage ratio SOC and the battery temperature Tb. I do. The input / output limits Win and Wout are the maximum allowable power that may charge / discharge the battery 50.

  Although not shown, the HVECU 70 is configured as a microprocessor centered on a CPU, and includes a ROM for storing a processing program, a RAM for temporarily storing data, an input / output port, and a communication port in addition to the CPU. Signals from various sensors are input to the HVECU 70 via input ports. Examples of the signals from the various sensors include an ignition signal from the ignition switch 80 and a shift position SP from the shift position sensor 82 that detects the operation position of the shift lever 81. Further, the accelerator opening Acc from the accelerator pedal position sensor 84 that detects the depression amount of the accelerator pedal 83, the brake pedal position BP from the brake pedal position sensor 86 that detects the depression amount of the brake pedal 85, and the vehicle speed sensor 88 The vehicle speed V can also be mentioned. As described above, the HVECU 70 is connected to the engine ECU 24, the motor ECU 40, and the battery ECU 52 via the communication port.

  In the embodiment, the engine device 21 mainly includes the engine 22 and the engine ECU 24.

  In the hybrid vehicle 20 of the embodiment thus configured, the required torque Tp * of the drive shaft 36 is set based on the accelerator opening Acc and the vehicle speed V, and the input / output limit Win of the battery 50 is accompanied by intermittent operation of the engine 22. , Wout, the engine 22 and the motors MG1, MG2 are controlled so that the required torque Tp * is output to the drive shaft 36.

  Further, in the hybrid vehicle 20 of the embodiment, when the engine ECU 24 is requested to stop the engine 22, the engine ECU 24 stops the fuel injection of the engine 22 while delaying the intake valve opening / closing timing VT to a predetermined timing. Control. In the embodiment, as the predetermined timing, the latest timing among the possible ranges of the opening / closing timing VT of the intake valve is used. In the embodiment, the fuel injection of the engine 22 is stopped after a predetermined time has elapsed since the request for stopping the engine 22 was made.

  Next, the operation of the hybrid vehicle 20 of the embodiment thus configured, particularly the operation when the stop request of the engine 22 is requested and the opening / closing timing VT of the intake valve is delayed will be described. FIG. 2 is a flowchart illustrating an example of a control routine executed by the engine ECU 24 of the embodiment. This control routine is repeatedly executed until the engine 22 stops rotating after the stop request of the engine 22 is made.

  When the control routine is executed, the engine ECU 24 first inputs the volume efficiency KL and the phase angle θvvt of the engine 22 (step S100). Here, the volume efficiency KL of the engine 22 is input as a value calculated based on the intake air amount Qa from the air flow meter 22c and the rotational speed Ne of the engine 22. As the phase angle θvvt, a value calculated as the angle (θci−θcr) of the cam angle θci of the intake camshaft from the cam position sensor 22b with respect to the crank angle θcr from the crank position sensor 22a is input.

  Next, it is determined whether or not the fuel injection of the engine 22 is being performed (before the fuel injection of the engine 22 is stopped) (step S110). When the fuel injection of the engine 22 is being performed, the volume efficiency KL of the engine 22 is compared with the threshold value KLref (step S120). Here, the threshold value KLref is the volume of the engine 22 that is assumed that the intake air amount Qa of the engine 22 does not fall below the lower limit air amount necessary for combustion even if the opening / closing timing VT of the intake valve is quickly delayed to the latest timing. It is determined as a lower limit value of efficiency KL or a value slightly larger than that.

  When the volume efficiency KL of the engine 22 is greater than or equal to the threshold KLref, the most retarded phase angle θret is set to the target phase angle θvvt * as the target value of the phase angle θvvt (step S150), and the phase angle θvvt is the target phase angle θvvt. The variable valve timing mechanism 23 is controlled to become * (step S160), and this routine is finished. Here, the most retarded phase angle θret is the phase angle θvvt when the intake valve opening / closing timing VT is the latest timing. By such control, the opening / closing timing VT of the intake valve can be quickly delayed to the latest timing. When the volumetric efficiency KL of the engine 22 is equal to or greater than the threshold KLref, the intake air amount Qa of the engine 22 is relatively large. Therefore, even if the intake valve opening / closing timing VT is quickly delayed to the latest timing, the engine 22 The possibility that the intake air amount Qa is less than the lower limit air amount necessary for combustion is considered to be low.

  When the volumetric efficiency KL of the engine 22 is less than the threshold KLref in step S120, the phase angle θvvt is compared with the most retarded phase angle θret (step S130). When the phase angle θvvt is larger than the most retarded phase angle θret (on the advance side), a predetermined phase angle Δθvvt from the target phase angle θvvt * (previous θvvt *) set when the previous routine is executed. A target phase angle θvvt * is set by guarding the value obtained by subtracting the lower limit with the most retarded phase angle θret (step S140), and the variable valve timing mechanism 23 is controlled so that the phase angle θvvt becomes the target phase angle θvvt *. (Step S160), and this routine ends. By repeating the processes of steps S100 to S140 and S160 in this way, the target phase angle θvvt * (phase angle θvvt) is gradually delayed by a predetermined phase angle Δθvvt toward the most retarded phase angle θret. Here, the predetermined phase angle Δθvvt is determined based on the specification of the variable valve timing mechanism 23 as a rate value (amount of change at the execution interval of this routine) when the target phase angle θvvt * is gradually delayed. In this way, the target phase angle θvvt * is gradually delayed toward the most retarded phase angle θret, so that the target phase angle θvvt * (phase angle θvvt) is immediately set to the most retarded phase angle θret. In comparison, it is possible to suppress the intake air amount Qa of the engine 22 from becoming relatively small and below the lower limit air amount necessary for combustion. As a result, it is possible to suppress the occurrence of misfire in the engine 22. In particular, in the embodiment, since the variable valve timing mechanism 23 is an electric type driven by a motor, the target phase angle θvvt * of the phase angle θvvt is compared with a case where a hydraulic type driven by hydraulic pressure is used. High follow-up performance. Therefore, if the target phase angle θvvt * is quickly changed, the phase angle θvvt also changes quickly, so that the intake air amount Qa of the engine 22 is likely to fall below the lower limit air amount necessary for combustion. For this reason, it is more significant to gradually reduce the target phase angle θvvt *.

  When the phase angle θvvt is equal to or smaller than the most retarded phase angle θret in step S130, the processing in steps S150 and S160 described above is executed, and this routine is terminated. In this case, the phase angle θvvt is held at the most retarded phase angle θret.

  When the fuel injection of the engine 22 is not being performed in step S110, it is determined that the fuel injection of the engine 22 is stopped, the processes of steps S150 and S160 described above are executed, and this routine is terminated. As a result, when the fuel injection of the engine 22 is stopped and the phase angle θvvt is larger than the most retarded phase angle θret (advanced side), the intake valve opening / closing timing VT is quickly set to the latest timing. Can be late.

  FIG. 3 is an explanatory diagram showing an example of a state in which the phase angle θvvt of the variable valve timing mechanism 23 is delayed in response to a request to stop the engine 22 when the load on the engine 22 is relatively small. In the figure, the solid line shows the state of the example, and the alternate long and short dash line shows the state of the comparative example. In the comparative example, the most retarded phase angle θret is immediately set to the target phase angle θvvt * regardless of the volumetric efficiency KL of the engine 22. When the engine 22 is requested to stop (time t1), in the comparative example, the phase angle θret of the most retarded angle is immediately set to the target phase angle θvvt * as shown by the alternate long and short dash line in FIG. The speed is quickly reduced to the most retarded phase angle θret. In this case, the volume efficiency KL of the engine 22 decreases and the rotational speed Ne of the engine 22 decreases from when the engine 22 is requested to stop (time t1) to when the fuel injection of the engine 22 is stopped (time t2). It is falling. As a cause of this, the fact that the phase angle θvvt quickly decreases to the most retarded phase angle θret causes the intake air amount Qa of the engine 22 to fall below the lower limit air amount necessary for combustion, causing a misfire in the engine 22. Conceivable. On the other hand, in the embodiment, when the engine 22 is requested to stop (time t1), the target phase angle θvvt * is gradually delayed toward the most retarded phase angle θret. In this case, the reduction in volumetric efficiency KL of the engine 22 is suppressed after the stop request of the engine 22 is made (time t1) until the fuel injection of the engine 22 is stopped (time t2). A reduction in the rotational speed Ne is suppressed. As this factor, the phase angle θvvt gradually decreases toward the most retarded phase angle θret, so that the intake air amount Qa of the engine 22 is suppressed from falling below the lower limit air amount necessary for combustion. It is possible that the occurrence of misfire is suppressed.

  In the hybrid vehicle 20 described above, when the engine 22 is requested to stop, the engine 22 is controlled to stop the fuel injection of the engine 22 while delaying the intake valve opening / closing timing VT to the latest timing. . Further, when the engine 22 is requested to stop and the volumetric efficiency KL of the engine 22 is less than the threshold value KLref, the target phase angle θvvt * is set so as to gradually decrease toward the most retarded phase angle θret. The variable valve timing mechanism 23 is controlled so that the phase angle θvvt becomes the target phase angle θvvt *. Accordingly, the intake air amount Qa of the engine 22 is relatively small and less than the lower limit air amount necessary for combustion is compared with the case where the most retarded phase angle θret is immediately set to the target phase angle θvvt *. can do. As a result, it is possible to suppress the occurrence of misfire in the engine 22.

  In the hybrid vehicle 20 of the embodiment, the variable valve timing mechanism 23 is driven by a motor, but may be driven by hydraulic pressure.

  In the embodiment, the engine device 21 is mounted on the hybrid vehicle 20 including the engine 22, the planetary gear 30, and the motors MG1 and MG2. However, the configuration of an engine device mounted on a so-called one-motor hybrid vehicle provided with an engine and one motor may be used, or an engine device mounted on a vehicle that travels using only power from the engine without a motor. It is good also as a structure. Moreover, it is good also as a structure of the engine apparatus mounted in the equipment which does not move, such as construction equipment.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the engine 22 corresponds to “engine”, and the engine ECU 24 corresponds to “control means”.

  The correspondence between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problem is the same as that of the embodiment described in the column of means for solving the problem. Therefore, the elements of the invention described in the column of means for solving the problems are not limited. In other words, the interpretation of the invention described in the column of means for solving the problem should be made based on the description of the column, and the examples are those of the invention described in the column of means for solving the problem. It is only a specific example.

  As mentioned above, although the form for implementing this invention was demonstrated using the Example, this invention is not limited at all to such an Example, In the range which does not deviate from the summary of this invention, it is with various forms. Of course, it can be implemented.

  The present invention is applicable to the engine device manufacturing industry.

20 Hybrid Vehicle, 21 Engine Device, 22 Engine, 22a Crank Position Sensor, 22b Cam Position Sensor, 22c Air Flow Meter, 23 Variable Valve Timing Mechanism, 24 Engine Electronic Control Unit (Engine ECU), 26 Crankshaft, 30 Planetary Gear, 36 Drive shaft, 37 differential gear, 38a, 38b drive wheel, 40 motor electronic control unit (motor ECU), 41, 42 inverter, 43, 44 rotational position detection sensor, 50 battery, 52 battery electronic control unit (battery ECU) , 70 Hybrid electronic control unit (HVECU), 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 a Cell pedal position sensor, 85 brake pedal, 86 a brake pedal position sensor, 88 vehicle speed sensor.

Claims (1)

An engine having a variable valve timing mechanism capable of changing the opening and closing timing of the intake valve;
Control means for controlling the engine to stop fuel injection of the engine while delaying the opening and closing timing to a predetermined timing when the engine stop request is made;
An engine device comprising:
When the engine stop request is made and the engine load is equal to or higher than the predetermined load, the control means immediately sets the predetermined timing as a target timing, and when the engine load is lower than the predetermined load, The target timing is set so as to be gradually delayed toward the predetermined timing, and the variable valve timing mechanism is controlled using the target timing.
Engine equipment.

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