Engine device

Abstract

To suppress deterioration of emission.SOLUTION: An engine device comprises an engine with a purification catalyst attached to an exhaust system, and a motor connected to an output shaft of the engine via a clutch. When torque control that controls the engine based on required torque is permitted after starting fuel injection and ignition of the engine from a state of fuel cut of the engine, the required torque is limited compared to when the elapsed time is equal to or larger than a time threshold when an elapsed time from the complete explosion of the engine is less than the time threshold.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to an engine device, and more particularly to an engine device including an engine and a motor connected to an output shaft of the engine via a clutch. [Background technology]

[0002] Conventionally, as this type of engine device, one that is installed in a hybrid vehicle that includes an engine, a motor connected to the output shaft of the engine via a clutch, and an automatic transmission connected to the rotating shaft of the motor and an axle has been proposed (see, for example, Patent Document 1). In this engine device, when the vehicle is driven by the motor with the clutch released, the engine is started while controlling the clutch toward engagement. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] JP 2020-111276 A Summary of the Invention [Problem to be solved by the invention]

[0004] It is preferable to output torque from the engine relatively soon after starting fuel injection and ignition in the engine from a fuel cut state, but there is a concern that emissions may worsen when the purification catalyst cannot exert sufficient purification performance, such as immediately after fuel injection and ignition are started.

[0005] The main object of the engine device of the present invention is to suppress deterioration of emissions. [Means for solving the problem]

[0006] In order to achieve the above-mentioned main object, the engine device of the present invention employs the following means.

[0007] The engine device of the present invention comprises: An engine device including an engine having a purification catalyst attached to an exhaust system, a motor connected to an output shaft of the engine via a clutch, and a control device that controls the engine, the motor, and the clutch, When the control device permits torque control for controlling the engine based on a required torque after starting fuel injection and ignition of the engine from a fuel cut state of the engine, and when the elapsed time from the complete explosion of the engine is less than a time threshold, the control device limits the required torque compared to when the elapsed time is equal to or greater than the time threshold. The gist of the present invention is as follows.

[0008] In the engine device of the present invention, when torque control for controlling the engine based on the required torque is permitted after starting fuel injection and ignition of the engine from a fuel cut state, if the elapsed time from the complete explosion of the engine is less than a time threshold, the required torque is limited compared to when the elapsed time is equal to or greater than the time threshold, thereby making it possible to suppress the deterioration of emissions.

[0009] In the engine device of the present invention, the control device may permit the torque control when, after starting the fuel injection and the ignition, the engine speed is equal to or higher than a first speed, and calculated injection control is performed as fuel injection control to control the fuel injection valve using a target injection amount based on the amount of air in the cylinder, and the engine speed is equal to or higher than a predetermined amount.

[0010] In the engine device of the present invention, the control device may determine the complete combustion when the engine speed is equal to or higher than a second speed (a speed higher than the first speed) and the condition that ignition has started is satisfied. In this way, the complete combustion of the engine can be determined more appropriately.

[0011] In the engine device of the present invention, the control device may select and execute one of a plurality of starting controls including a first starting control that controls the engine, the motor, and the clutch so as to partially engage the clutch in response to a request to start the engine, crank the engine by the motor, initiate the fuel injection and the ignition in the cylinder that first reaches top dead center of compression or the cylinder that second reaches top dead center of compression, and then release the clutch to reduce a differential rotation speed between the engine speed and the motor rotation speed, and engage the clutch when the differential rotation speed reaches less than a predetermined differential rotation speed; and a second starting control that controls the engine, the motor, and the clutch so as to partially engage the clutch and crank the engine by the motor, and engage the clutch and then initiate the fuel injection and the ignition when the differential rotation speed reaches less than the predetermined differential rotation speed.

[0012] In the engine device of the present invention in an aspect in which one of a plurality of start controls is selected and executed, the time threshold may be set based on at least one of the type of the start control and the engine coolant temperature. In this case, the time threshold may be set to be longer in the second start control than in the first start control. This is because it is considered that in the second start control, the oxygen storage amount of the purification catalyst is likely to be larger than in the first start control, and the time required for the purification catalyst to be able to exhibit sufficient purification performance is likely to be longer. In addition, the time threshold may be set to be less likely to be lower when the coolant temperature is lower. This is because it is considered that the lower the coolant temperature, the lower the temperature of the purification catalyst is, and the time required for the purification catalyst to be able to exhibit sufficient purification performance is likely to be longer.

[0013] In the engine device of the present invention, when the torque control is permitted and the elapsed time is less than the time threshold value, the control device may reset the required torque by guarding the upper limit of the required torque with an upper limit torque. In this case, the upper limit torque may be set based on at least one of the engine cooling water temperature and a second elapsed time from the start of the fuel injection and the ignition. In this case, the upper limit torque may be set to be smaller in the second start control than in the first start control. This is because it is considered that the oxygen storage amount of the purification catalyst is more likely to be large in the second start control than in the first start control, and the purification performance of the purification catalyst is lower. In addition, the upper limit torque may be set to be smaller as the cooling water temperature is lower. This is because it is considered that the lower the cooling water temperature is, the lower the temperature of the purification catalyst is, and the purification performance of the purification catalyst is lower. Furthermore, the upper limit torque may be set to be larger as the second elapsed time is longer. This is because it is considered that the longer the elapsed time is, the higher the temperature of the purification catalyst is, and the purification performance of the purification catalyst is improved.

[0014] In the engine device of the present invention in which one of a plurality of start controls is selected and executed, and when the elapsed time is less than a time threshold, the required torque is reset by guarding the upper limit with the upper limit torque, the upper limit torque may be set based on the type of the start control. In this case, the upper limit torque may be set to be longer in the case of the second start control than in the case of the first start control. This is because it is considered that the oxygen storage amount of the purification catalyst is more likely to be large in the case of the second start control than in the case of the first start control, and the purification performance of the purification catalyst is lowered. [Brief description of the drawings]

[0015] [Figure 1] 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 equipped with an engine device as an embodiment of the present invention. [Diagram 2] 1 is a diagram showing an outline of the configuration of an engine 22 mounted on a hybrid vehicle 20. FIG. [Diagram 3] 4 is a flowchart showing an example of a torque control-related process executed by an engine ECU 24 in the embodiment. [Figure 4] 11 is a time chart showing an example of the rotation speed Nmg of the motor 30, the rotation speed Ne of the engine 22, the elapsed time Tce from the determination of complete combustion, whether or not torque control is permitted, and the degree of acceptance of the required torque Te* during TDC start control. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0016] Next, a mode for carrying out the present invention will be described using examples. EXAMPLES

[0017] Fig. 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with an engine device according to an embodiment of the present invention. Fig. 2 is a schematic diagram showing the configuration of an engine 22 equipped in the hybrid vehicle 20. As shown in Fig. 1, the hybrid vehicle 20 of the embodiment includes the engine 22, a motor 30, an inverter 32, a clutch K0, an automatic transmission 40, a high-voltage battery 60, a low-voltage battery 62, a DC / DC converter 64, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0018] The engine 22 is configured as a six-cylinder internal combustion engine that uses fuel such as gasoline or diesel to output power through four strokes: intake, compression, expansion (explosive combustion), and exhaust. As shown in FIG. 2, the engine 22 has a port injection valve 126 that injects fuel into an intake port, and an in-cylinder injection valve 127 that injects fuel into a cylinder. The engine 22 can be operated in any one of a port injection mode, an in-cylinder injection mode, and a common injection mode by having the port injection valve 126 and the in-cylinder injection valve 127. In the port injection mode, air purified by the air cleaner 122 is sucked into the intake pipe 123 and passes through the throttle valve 124 and the surge tank 125, and fuel is injected from the port injection valve 126 downstream of the surge tank 125 of the intake pipe 123, and the air and fuel are mixed. This mixture is then drawn into the combustion chamber 129 via the intake valve 128, where it is explosively combusted by an electric spark from the spark plug 130, and the reciprocating motion of the piston 132, which is pushed down in the cylinder bore by the energy of the mixture, is converted into the rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is drawn into the combustion chamber 129 in the same manner as in the port injection mode, and fuel is injected from the in-cylinder injection valve 127 during the intake stroke and compression stroke, and is explosively combusted by an electric spark from the spark plug 130, to obtain the rotational motion of the crankshaft 23. In the shared injection mode, fuel is injected from the port injection valve 126 when air is drawn into the combustion chamber 129, and fuel is injected from the in-cylinder injection valve 127 during the intake stroke and compression stroke, and is explosively combusted by an electric spark from the spark plug 130, to obtain the rotational motion of the crankshaft 23. These injection modes are switched based on the operating state of the engine 22. Exhaust discharged from the combustion chamber 129 to an exhaust pipe 134 via an exhaust valve 133 is discharged into the outside air via a purification device 135 and a PM filter 136. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components in the exhaust such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx). The PM filter 136 is formed as a porous filter from ceramics, stainless steel, or the like, and collects particulate matter (PM) such as soot in the exhaust.In place of the PM filter 136, a four-way catalyst that combines the purification function of a three-way catalyst with the function of trapping particulate matter may be used.

[0019] The operation of the engine 22 is controlled by the engine ECU 24. The engine ECU 24 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports, not shown. Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 via input ports. Examples of signals input to the engine ECU 24 include a crank angle θcr from a crank position sensor 140 that detects the rotational position of the crankshaft 23 of the engine 22, and a cooling water temperature Tw from a water temperature sensor 142 that detects the temperature of the cooling water of the engine 22. Other examples of signals input to the engine ECU 24 include cam angles θci and θco from a cam position sensor 144 that detects the rotational position of an intake camshaft that opens and closes the intake valve 128 and the rotational position of an exhaust camshaft that opens and closes the exhaust valve 133. Other examples of the above include the throttle opening TH from a throttle valve position sensor 124a that detects the position of the throttle valve 124, the intake air amount Qa from an air flow meter 123a attached upstream of the throttle valve 124 of the intake pipe 123, the intake air temperature Ta from a temperature sensor 123t attached upstream of the throttle valve 124 of the intake pipe 123, and the surge pressure Ps from a pressure sensor 125a attached to the surge tank 125. Other examples of the above include a front air-fuel ratio AF1 from a front air-fuel ratio sensor 137 attached upstream of the purification device 135 of the exhaust pipe 134, a rear air-fuel ratio AF2 from a rear air-fuel ratio sensor 138 attached between the purification device 135 of the exhaust pipe 134 and the PM filter 136, and a differential pressure ΔP from a differential pressure sensor 136a that detects a differential pressure before and after the PM filter 136 (a differential pressure between the upstream side and the downstream side).

[0020] From the engine ECU 24, various control signals for controlling the operation of the engine 22 are output via an output port. Examples of signals output from the engine ECU 24 include a control signal to a throttle valve 124, a control signal to a port injection valve 126, a control signal to an in-cylinder injection valve 127, and a control signal to an ignition plug 130.

[0021] The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140. The engine ECU 24 also calculates a load factor KL (the ratio of the volume of air actually taken in one cycle to the stroke volume per cycle of the engine 22) based on the intake air amount Qa from the air flow meter 123a and the rotation speed Ne of the engine 22. Furthermore, the engine ECU 24 calculates a PM accumulation amount Qpm as the accumulation amount of particulate matter accumulated on the PM filter 136 based on a differential pressure ΔP from the differential pressure sensor 136a, and calculates a filter temperature tf as the temperature of the PM filter 136 based on the rotation speed Ne of the engine 22 and the load factor KL.

[0022] 1, a starter motor 25 for cranking the engine 22 and an alternator 26 for generating power using power from the engine 22 are connected to the crankshaft 23 of the engine 22. The starter motor 25 and the alternator 26 are connected to a low-voltage power line 63 together with a low-voltage battery 62, and are controlled by the HVECU 70.

[0023] The motor 30 is configured as a synchronous generator motor, and has a rotor in which a permanent magnet is embedded in a rotor core, and a stator in which a three-phase coil is wound around a stator core. A rotating shaft 31 to which the rotor of the motor 30 is fixed is connected to the crankshaft 23 of the engine 22 via a clutch K0, and is also connected to an input shaft 41 of an automatic transmission 45. The inverter 32 is used to drive the motor 30, and is connected to a high-voltage power line 61. The motor 30 is rotationally driven by a motor electronic control unit (hereinafter referred to as "motor ECU") 34 controlling the switching of multiple switching elements of the inverter 32.

[0024] Although not shown, the motor ECU 34 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. Signals from various sensors are input to the motor ECU 34 via the input port. Examples of signals input to the motor ECU 34 include a rotational position θmg from a rotational position sensor 30a that detects the rotational position of the rotor (rotating shaft 31) of the motor 30, and phase currents Iu and Iv from current sensors that detect the phase currents of the respective phases of the motor 30. A control signal to the inverter 32 and the like are output from the motor ECU 34 via an output port. The motor ECU 34 is connected to the HVECU 70 via a communication port. The motor ECU 34 calculates the rotational speed Nmg of the motor 30 based on the rotational position θmg of the rotor (rotating shaft 31) of the motor 30 from the rotational position sensor 30a.

[0025] The clutch K0 is configured as, for example, a hydraulically driven friction clutch, and is controlled by the HVECU 70 to connect and disconnect the crankshaft 23 of the engine 22 and the rotating shaft 31 of the motor 30.

[0026] The automatic transmission 40 has a torque converter 43 and an automatic transmission 45 with, for example, six speeds. The torque converter 43 is configured as a general fluid transmission device, and transmits the power of an input shaft 41 connected to a rotating shaft 31 of the motor 30 to a transmission input shaft 44 which is an input shaft of the automatic transmission 45 with amplified torque, or transmits the torque as is without amplifying it. The automatic transmission 45 has the transmission input shaft 44, an output shaft 42 connected to driving wheels 49 via a differential gear 48, a plurality of planetary gears, and a plurality of hydraulically driven friction engagement elements (clutches, brakes). Each of the plurality of friction engagement elements has a hydraulic servo configured of a piston, a plurality of friction engagement plates (friction plates and separator plates), an oil chamber to which hydraulic oil is supplied, and the like. The automatic transmission 45 forms forward gears from 1st gear to 6th gear and reverse gears by engaging and disengaging a plurality of friction engagement elements, and transmits power between the transmission input shaft 44 and the output shaft 42. The hydraulic pressure of hydraulic oil from a mechanical oil pump or an electric oil pump is adjusted and supplied to the clutch K0 and the automatic transmission 45 by a hydraulic control device (not shown). The hydraulic control device has a valve body with a plurality of oil passages formed therein, a plurality of regulator valves, a plurality of linear solenoid valves, etc. This hydraulic control device is controlled by the HVECU 70.

[0027] High-voltage battery 60 is configured as, for example, a lithium-ion secondary battery or a nickel-hydrogen secondary battery with a rated voltage of several hundred volts, and is connected to high-voltage power line 61 together with inverter 32. Low-voltage battery 62 is configured as, for example, a lead-acid battery with a rated voltage of about 12 V or 14 V, and is connected to low-voltage power line 63 together with starter motor 25 and alternator 26. DC / DC converter 64 is connected to high-voltage power line 61 and low-voltage power line 63. This DC / DC converter 64 supplies power from high-voltage power line 61 to low-voltage power line 63 with a voltage step-down.

[0028] Although not shown, the HVECU 70 includes a microcomputer having a CPU, a ROM, a RAM, a flash memory, an input / output port, and a communication port. Signals from various sensors are input to the HVECU 70 via the input port. Examples of signals input to the HVECU 70 include the rotation speed Nin from the rotation speed sensor 41a attached to the input shaft 41 of the automatic transmission 40, the rotation speed Nmi from the rotation speed sensor 44a attached to the transmission input shaft 44 of the automatic transmission 40, and the rotation speed Nout from the rotation speed sensor 42a attached to the output shaft 42 of the automatic transmission 40. Examples of signals input to the HVECU 70 include the voltage Vbh of the high-voltage battery 60 from a voltage sensor attached between the terminals of the high-voltage battery 60, the current Ibh of the high-voltage battery 60 from a current sensor attached to the output terminal of the high-voltage battery 60, and the voltage Vbl from a voltage sensor attached between the terminals of the low-voltage battery 62. Other examples of such signals include an ignition signal from an ignition switch 80, a shift position SP from a shift position sensor 82 that detects the operating position of a shift lever 81, an accelerator opening Acc from an accelerator pedal position sensor 84 that detects the amount of depression of an accelerator pedal 83, a brake pedal position BP from a brake pedal position sensor 86 that detects the amount of depression of a brake pedal 85, and a vehicle speed V from a vehicle speed sensor 87.

[0029] Various control signals are output from the HVECU 70 via an output port. Examples of signals output from the HVECU 70 include a control signal to the starter motor 25 and a control signal to the alternator 26. Examples of signals output from the HVECU 70 include a control signal to the clutch K0 and the automatic transmission 40 (hydraulic control device), and a control signal to the DC / DC converter 64. The HVECU 70 is connected to the engine ECU 24 and the motor ECU 34 via a communication port. The HVECU 70 calculates a rotation speed ratio Gt of the automatic transmission 40 by dividing the rotation speed Nin of the input shaft 41 of the automatic transmission 40 from the rotation speed sensor 41a by the rotation speed Nout of the output shaft 42 of the automatic transmission 40 from the rotation speed sensor 42a.

[0030] In this embodiment, the engine device corresponds to the engine 22, the clutch K0, the motor 30, the HVECU 70, the engine ECU 24, and the motor ECU .

[0031] In the hybrid vehicle 20 of the embodiment thus configured, the engine 22, the clutch K0, the motor 30, and the automatic transmission 40 are controlled by cooperative control between the HVECU 70, the engine ECU 24, and the motor ECU 34 so as to travel in a hybrid driving mode (HV driving mode) or an electric driving mode (EV driving mode). Here, the HV driving mode is a mode in which the clutch K0 is in an engaged state and the vehicle travels using the power of the engine 22, and the EV driving mode is a mode in which the clutch K0 is in a released state and the vehicle travels without using the power of the engine 22.

[0032] In controlling the automatic transmission 40 in the HV driving mode or the EV driving mode, the HVECU 70 first sets a target gear M* of the automatic transmission 45 based on the accelerator opening Acc and the vehicle speed V. Then, when the gear M of the automatic transmission 45 matches the target gear M*, the HVECU 70 controls the automatic transmission 45 so that the gear M is maintained. On the other hand, when the gear M and the target gear M* differ, the HVECU 70 controls the automatic transmission 45 so that the gear M matches the target gear M*.

[0033] In controlling the engine 22 and the motor 30 in the HV driving mode, the HVECU 70 first sets a required torque Tout* required for driving (required of the output shaft 42 of the automatic transmission 40) based on the accelerator opening Acc and the vehicle speed V. Next, the HVECU 70 sets a value obtained by dividing the required torque Tout* of the output shaft 42 by the rotation speed ratio Gt of the automatic transmission 40 as the required torque Tin* of the input shaft 41. After setting the required torque Tin* of the input shaft 41 in this manner, the HVECU 70 sets the required torque Te* of the engine 22 and the torque command Tm* of the motor 30 so that the required torque Tin* is output to the input shaft 41, and transmits the required torque Te* of the engine 22 to the engine ECU 24 and transmits the torque command Tm* of the motor 30 to the motor ECU 34. When the engine ECU 24 receives the required torque Te*, it performs operation control of the engine 22 (air amount control to control the throttle valve 124, fuel injection control to control the port injection valve 126 and the in-cylinder injection valve 127, ignition control to control the spark plug 130, etc.) so that the engine 22 operates at the required torque Te*. When the motor ECU 34 receives the torque command Tm*, it performs switching control of multiple switching elements of the inverter 32 so that the motor 30 is driven at the torque command Tm*.

[0034] In controlling the motor 30 in the EV driving mode, the HVECU 70 sets a required torque Tin* of the input shaft 41 in the same manner as in the HV driving mode, sets a torque command Tm* of the motor 30 so that the required torque Tin* is output to the input shaft 41, and transmits the torque command Tm* to the motor ECU 34. Upon receiving the torque command Tm*, the motor ECU 34 performs switching control of a plurality of switching elements of the inverter 32 so that the motor 30 is driven by the torque command Tm*.

[0035] In the hybrid vehicle 20 of the embodiment, when a request to stop the engine 22 is made while the engine 22 is in operation, the engine ECU 24 and the motor ECU 34 perform a stop control of the engine 22 by cooperative control. The stop request is made, for example, when a condition is satisfied that the required torque Tin* of the input shaft 41 is less than the threshold value Tinref. In the stop control, basically, fuel injection and ignition are stopped and the throttle valve 124 is closed, and when the rotation speed Ne of the engine 22 falls below a threshold value Neref1 (for example, about 600 rpm to 800 rpm), the clutch K0 is released, and further, when the rotation speed Ne of the engine 22 falls below a threshold value Neref2 lower than the threshold value Neref1 (for example, about several hundred rpm lower), the throttle valve 124 is temporarily opened. The reason for temporarily opening the throttle valve 124 will be described later.

[0036] When a request to start the engine 22 is made while fuel injection and ignition of the engine 22 are stopped, the start control of the engine 22 is executed. The start request is made, for example, when a condition is satisfied that the required torque Tin* is equal to or greater than a threshold value Tinref. Examples of the types of start control of the engine 22 include FC (Fuel Cut) recovery start control, independent COM (Change Of Mind) start control, COM start control, TDC (Top Dead Center) start control, and PUSH start control. The type of start control is selected based on, for example, the rotation speed Ne of the engine 22 and the rotation speed Nmg of the motor 30 when the start request is made (started). Note that the fuel injection control during the start control is performed in an in-cylinder injection mode.

[0037] The FC recovery start control is basically performed when a start request is made and the rotation speed Ne of the engine 22 is equal to or greater than the threshold value Neref1 (the clutch K0 is engaged) and the rotation speed Nmg of the motor 30 is equal to or greater than the threshold value Nmgref (for example, the same value as the threshold value Neref1). In the FC recovery start control, basically, fuel injection and ignition of the engine 22 are started while continuing to engage the clutch K0. In the embodiment, after fuel injection and ignition of the engine 22 are started and when the clutch K0 is engaged, a required torque Te* similar to that in the HV driving mode is set by the HVECU 70 and transmitted to the engine ECU 24.

[0038] The independent COM start control is basically performed when a start request is made, the engine 22 speed Ne is less than the threshold Neref1 (the clutch K0 is released) and is equal to or greater than a threshold Neref3 lower than the threshold Neref1 (e.g., several hundred rpm lower), and the motor 30 speed Nmg is equal to or greater than the threshold Nmgref. In the independent COM start control, the engine 22 is basically started to inject fuel and ignite while the clutch K0 is continuously released, the engine 22 is controlled by setting the required torque Te* so that the differential speed ΔN between the motor 30 speed Nmg and the engine 22 speed Ne is reduced, and the clutch K0 is engaged when the clutch K0 engagement condition is satisfied. In the embodiment, the required torque Te* for reducing the differential speed ΔN is set by the HVECU 70 and transmitted to the engine ECU 24. As the clutch K0 engagement condition, for example, a condition that the differential speed ΔN is less than a threshold ΔNref (e.g., about 50 rpm to 150 rpm) can be used.

[0039] COM start control is basically performed when a start request is made, the rotation speed Ne of the engine 22 is less than the threshold value Neref3 and greater than the value 0, and the rotation speed Nmg of the motor 30 is equal to or greater than the threshold value Nmgref. In the COM start control, the clutch K0 is basically half-engaged (slip-engaged) and the engine 22 is cranked using the cranking torque from the motor 30 while fuel injection and ignition are started, the required torque Te* is set so that the differential rotation speed ΔN is reduced, and the clutch K0 is released while controlling the engine 22, and when the above-mentioned engagement condition for the clutch K0 is satisfied, the clutch K0 is engaged.

[0040] Basically, the TDC start control is performed when a start request is made and the engine 22 speed Ne is 0 (the engine 22 is stopped) and the motor 30 speed Nmg is equal to or greater than the threshold value Nmgref. Basically, the TDC start control half-engages (slips) the clutch K0 to crank the engine 22 using the cranking torque from the motor 30, starts fuel injection and ignition in the cylinder that reaches the compression top dead center first (the first target cylinder) or the cylinder that reaches the compression top dead center second (the second target cylinder), sets the required torque Te* so that the differential speed ΔN is small, and releases the clutch K0 while controlling the engine 22, and engages the clutch K0 when the above-mentioned clutch K0 engagement condition is satisfied. The selection of which of the first target cylinder and the second target cylinder to start fuel injection and ignition is basically made based on whether the crank angle (stop crank angle) θcrsp when the engine 22 is stopped intermittently (stopped rotating) is within a predetermined crank angle range (for example, BTDC40 to 80 (before TDC 40 degrees to 80 degrees)) in which the first explosion can be performed in the first target cylinder. Therefore, when the stop crank angle θcrsp is within the predetermined crank angle range, fuel injection and ignition are started in the first target cylinder, and when the stop crank angle θcrsp is not within the predetermined crank angle range, fuel injection and ignition are started in the second target cylinder. In the embodiment, as described above, when the rotation speed Ne of the engine 22 becomes less than the threshold value Neref2 during the stop control, the throttle valve 124 is temporarily opened. This is to increase the amount of air in the first target cylinder in preparation for the case where fuel injection and ignition are started in the first target cylinder.

[0041] PUSH start control is basically performed when a start request is made and the rotation speed Nmg of the motor 30 is less than the threshold value Nmgref. In PUSH start control, the clutch K0 is basically half-engaged (slip-engaged) to crank the engine 22 using the cranking torque from the motor 30, and when the above-mentioned clutch K0 engagement condition is met, the clutch K0 is engaged, and then fuel injection and ignition of the engine 22 are started.

[0042] In the embodiment, during FC recovery start control, calculated injection control is executed from the first fuel injection as fuel injection control that controls the in-cylinder injection valve 127 using the target injection amount Qf*. In the calculated injection control, the target injection amount Qf* is basically set based on the in-cylinder air amount Qcy so that the front air-fuel ratio AF1 becomes the target air-fuel ratio AF1* (e.g., the stoichiometric air-fuel ratio), and the set target injection amount Qf* is used to control the in-cylinder injection valve 127. The in-cylinder air amount Qcy can be calculated using an air model based on, for example, the required opening of the throttle valve 124 used for air amount control.

[0043] In addition, in the case of independent COM start control, COM start control, TDC start control, and PUSH start control, prospective injection control is executed as fuel injection control from the first fuel injection until a transition condition is satisfied, and when the transition condition is satisfied, the control transitions to calculated injection control. In prospective injection control, the target injection amount Qf* is basically set without being based on the predicted in-cylinder air amount Qcypr, the front air-fuel ratio AF1, or the target air-fuel ratio AF1*, and the in-cylinder injection valve 127 is controlled using the set target injection amount Qf*. As the target injection amount Qf* in prospective injection control in independent COM start control, COM start control, and PUSH start control, for example, a fixed amount can be used, or a value based on at least one of the rotation speed Ne of the engine 22 and the intake manifold pressure Pinc at the time of closing, which is the intake manifold pressure Pin (surge pressure Ps) when the intake valve 128 of the target cylinder is closed, can be used. The target injection amount Qf* in the prospective injection control in the TDC start control can be, for example, a fixed amount or a value based on at least one of the stop crank angle θcrsp and the elapsed time since the engine 22 stopped rotating. The transition condition for transitioning from the prospective injection control to the calculated injection control can be, for example, a condition that the number of fuel injections (number of fuel injection cylinders) is equal to or greater than a predetermined number (for example, about 4 to 8 times).

[0044] Next, the operation of the hybrid vehicle 20 of the embodiment will be described, in particular, the processing related to torque control that controls the engine 22 based on the required torque Te* during independent COM start control, COM start control, TDC start control, and PUSH start control (start control in which predictive injection control is executed as fuel injection control and then shifts to calculated injection control). Fig. 3 is a flowchart showing an example of the torque control related processing executed by the engine ECU 24 of the embodiment. This routine is executed when a start request for the engine 22 is made and one of independent COM start control, COM start control, TDC start control, and PUSH start control is selected and started.

[0045] 3 is executed, the engine ECU 24 first inputs data such as the rotation speed Ne of the engine 22, the calculated injection control flag Fc, and the rotation amount Qcr of the engine 22 from the start of the start request (step S100). Here, a value calculated based on the crank angle θcr from the crank position sensor 140 is input as the rotation speed Ne of the engine 22. The calculated injection control flag Fc is set to a value of 0 when prospective injection control is being executed as the fuel injection control, and is set to a value of 1 when calculated injection control is being executed as the fuel injection control. A value calculated as the change amount of the crank angle θcr from the start of the start request is input as the rotation amount Qcr of the engine 22 from the start of the start request.

[0046] When the data is input in this manner, it is determined whether the rotation speed Ne of the engine 22 is equal to or greater than a threshold value Neref1 (step S110), whether the calculated injection control flag Fc is set to a value of 1, i.e., whether calculated injection control is being executed as fuel injection control (step S120), and whether the rotation amount Qcr of the engine 22 from the start of the start request is equal to or greater than a threshold value Qcrref (step S130). The processing in steps S110 to S130 is processing for determining whether or not torque control is permitted as the control of the engine 22. The threshold value Neref1 is a threshold value used to determine whether or not the rotation speed Ne is relatively high, and for example, about 300 rpm to 500 rpm can be used. The threshold value Qcrref is a threshold value used to determine whether or not the amount of air in the cylinder is considered to change with sufficient sensitivity in response to a change in the throttle opening TH, and for example, about 480 degrees to 960 degrees can be used.

[0047] When it is determined in step S110 that the rotation speed Ne of the engine 22 is less than the threshold value Neref1, when it is determined in step S120 that the calculated injection control flag Fc is 0, i.e., that prospective injection control is being executed as fuel injection control, or when it is determined in step S130 that the rotation amount Qcr of the engine 22 from the start of the start request is less than the threshold value Qcrref, torque control is prohibited (step S140) and the process returns to step S100. In this case, regardless of the requested torque Te* from the HVECU 70, the engine 22 is controlled so that good startability is obtained based on the type of start control.

[0048] When it is determined in step S110 that the rotation speed Ne of the engine 22 is equal to or greater than the threshold value Neref1, and when it is determined in step S120 that the calculated injection control flag Fc is equal to the value 1, i.e., calculated injection control is being executed as fuel injection control, and when it is determined in step S130 that the rotation amount Qcr of the engine 22 from the start of the start request is equal to or greater than the threshold value Qcrref, torque control is permitted (step S150).

[0049] When the torque control is permitted in this way, the elapsed time Tce since the complete combustion determination of the engine 22 is input (step S160), and it is determined whether the input elapsed time Tce is equal to or greater than the threshold value Tceref (step S170). Here, the complete combustion determination of the engine 22 can be performed, for example, when the engine speed Ne of the engine 22 is equal to or greater than a threshold value Neref2 higher than the threshold value Neref1 and the condition that ignition has started (ignition is performed in any cylinder) is satisfied. For example, the threshold value Neref2 can be a speed that is about 100 rpm to 300 rpm higher than the threshold value Neref1. During the rotation of the engine 22 when fuel injection and ignition are stopped, air (oxygen) is supplied to the purification catalyst 135a, so that the amount of oxygen stored in the purification catalyst 135a tends to increase. For this reason, if the load factor KL of the engine 22 is increased in a relatively short time after the start of fuel injection and ignition (for example, immediately after torque control is permitted), the purification catalyst 135a may not be able to fully exert its purification performance, and emissions may deteriorate. Taking this into consideration, the process of step S170 is a process for determining whether the required torque Te* from the HVECU 70 should be accepted in a limited manner or fully accepted.

[0050] The threshold value Tceref can be a time, for example, about 100 msec to 200 msec, that is previously set by experiments, analysis, machine learning, etc. as the time required for the purification catalyst 135a to be able to exhibit sufficient purification performance. This threshold value Tceref can be set, for example, by predetermining the relationship between the type of start control and the cooling water temperature Tw and the threshold value Tceref by experiments, analysis, machine learning, etc., and storing it as a time threshold setting map, and when the type of start control and the cooling water temperature Tw are given, the corresponding threshold value Tceref can be derived from this map. The threshold value Tceref is set to be longer in the case of PUSH start control than in the case of TDC start control. This is because it is considered that in the case of PUSH start control, the amount of oxygen stored in the purification catalyst 135a is more likely to be large compared to the case of TDC start control, and the time required for the purification catalyst 135a to be able to exhibit sufficient purification performance is more likely to be longer. In addition, the threshold value Tceref is set to be longer as the cooling water temperature Tw is lower. This is because it is believed that the lower the cooling water temperature Tw, the lower the temperature of the purification catalyst 135a becomes, and the longer the time required for the purification catalyst 135a to be able to exhibit sufficient purification performance becomes.

[0051] When it is determined in step 170 that the elapsed time Tce since the complete explosion determination of the engine 22 is less than the threshold value Tceref, it is determined that the acceptance of the required torque Te* is permitted in a limited manner (step S180), and the process returns to step S160. In this case, the required torque Te* from the HVECU 70 is upper-guarded with the upper limit torque Temax, and the required torque Te* is reset, and the engine 22 is controlled based on the reset required torque Te*.

[0052] The upper limit torque Temax can be a torque, for example, about 50 Nm to 100 Nm, that is preset by experiment, analysis, machine learning, etc. as the upper limit of the torque range where emissions do not deteriorate. Therefore, by controlling the engine 22 based on the required torque Te* that is equal to or less than the upper limit torque Temax, it is possible to suppress deterioration of emissions. This upper limit torque Temax can be set by, for example, predetermining the relationship between the type of start control, the cooling water temperature Tw, the elapsed time Tfi from the start of fuel injection or ignition, and the upper limit torque Temax by experiment, analysis, machine learning, etc., and storing it as an upper limit torque setting map, and deriving the corresponding upper limit torque Temax from this map when the type of start control, the cooling water temperature Tw, and the elapsed time Tfi are given. The upper limit torque Temax is set to be smaller in the case of PUSH start control than in the case of TDC start control. This is because it is considered that the amount of oxygen stored in the purification catalyst 135a is more likely to be large in the case of PUSH start control than in the case of TDC start control, and the purification performance of the purification catalyst 135a is lower. Moreover, the upper limit torque Temax is set to be smaller as the cooling water temperature Tw is lower. This is because it is considered that the lower the cooling water temperature Tw, the lower the temperature of the purification catalyst 135a is, and the purification performance of the purification catalyst 135a is deteriorated. Furthermore, the upper limit torque Temax is set to be larger as the elapsed time Tfi is longer. This is because it is considered that the longer the elapsed time Tfi is, the higher the temperature of the purification catalyst 135a is, and the more the purification performance of the purification catalyst 135a is improved. In this way, the upper limit torque Temax can be set more appropriately.

[0053] When it is determined in step S170 that the elapsed time Tce since the complete explosion determination of the engine 22 is equal to or greater than the threshold value Tceref, it is determined that acceptance of the required torque Te* is completely permitted (step S190), and the start request is cancelled (step S200), and this process ends. When acceptance of the required torque Te* is completely permitted and the start request is cancelled, the mode transitions to the HV driving mode and the engine 22 is controlled based on the required torque Te* from the HVECU 70. This allows the engine 22 to fully respond to the required torque Te* from the HVECU 70.

[0054] FIG. 4 is a time chart showing an example of the rotation speed Nmg of the motor 30, the rotation speed Ne of the engine 22, the elapsed time Tce from the determination of complete combustion, the permission or denial of torque control, and the degree of acceptance of the required torque Te* during TDC start control. As described above, in the TDC start control, the clutch K0 is half-engaged to crank the engine 22 by the motor 30, fuel injection and ignition are started in the first target cylinder or the second target cylinder, the clutch K0 is released while controlling the engine 22 so that the differential rotation speed ΔN becomes small, and the clutch K0 is engaged when the engagement condition of the clutch K0 is satisfied. At this time, when the conditions that the rotation speed Ne of the engine 22 is equal to or greater than the threshold value Neref1, the calculated injection control is executed as the fuel injection control, and the rotation amount Qcr of the engine 22 from the start of the start request is equal to or greater than the threshold value Qcrref are satisfied (time t12), the torque control is switched from prohibited to permitted, and the acceptance of the required torque Te* is permitted in a limited manner. This makes it possible to suppress the deterioration of emissions. Thereafter, when the elapsed time Tce from the determination of the complete explosion of the engine 22 (time t11) reaches or exceeds the threshold value Tceref (time t13), the request torque Te* is completely permitted to be received, the start request is cancelled, and the mode is switched to the HV driving mode, so that the engine 22 can output a sufficient torque.

[0055] In the engine device mounted on the hybrid vehicle 20 of the embodiment described above, when torque control is permitted after fuel injection and ignition of the engine 22 are started, if the elapsed time Tce from the determination of complete explosion of the engine 22 is less than the threshold value Tceref, the required torque Te* is limited compared to when the elapsed time Tce is equal to or greater than the threshold value Tceref, specifically, the required torque Te* from the HVECU 70 is upper-guarded with the upper limit torque Temax, and the required torque Te* is reset to control the engine 22. This makes it possible to suppress the deterioration of emissions.

[0056] In the engine device mounted on the hybrid vehicle 20 of the embodiment, a time based on the type of starting control and the cooling water temperature Tw may be used as the threshold value Tceref used for comparison with the elapsed time Tce from the determination of complete explosion of the engine 22. However, a time based only on either the type of starting control or the cooling water temperature Tw may be used as the threshold value Tceref. Also, a fixed time may be used as the threshold value Tceref.

[0057] In the engine device mounted on the hybrid vehicle 20 of the embodiment, the upper limit torque Temax used when the acceptance of the required torque Te* is permitted in a limited manner is a torque based on the type of start control, the cooling water temperature Tw, and the elapsed time Tfi from the start of fuel injection or ignition. However, the upper limit torque Temax may be a torque based on some of the type of start control, the cooling water temperature Tw, and the elapsed time Tfi from the start of fuel injection or ignition. Also, a constant torque may be used as the upper limit torque Temax.

[0058] In the engine device mounted on the hybrid vehicle 20 of the embodiment, the threshold value Tceref and the upper limit torque Temax are set to time and torque that do not take into account the accelerator opening Acc. However, the threshold value Tceref and the upper limit torque Temax may be set to time and torque that are based on the accelerator opening Acc. In this case, in order to ensure running performance while slightly sacrificing the purification performance of the purification catalyst 135a when the accelerator opening Acc is large, it is possible to use, as the threshold value Tceref and the upper limit torque Temax, a time that becomes longer as the accelerator opening Acc becomes larger, or a torque that becomes larger as the accelerator opening Acc becomes larger.

[0059] The hybrid vehicle 20 of the embodiment is equipped with a six-speed automatic transmission 45. However, it may be equipped with a four-speed, five-speed, eight-speed, or other automatic transmission.

[0060] The hybrid vehicle 20 of the embodiment includes the engine ECU 24, the motor ECU 34, and the HVECU 70. However, at least two of these may be integrated into one unit.

[0061] Although the engine device of the embodiment is mounted on the hybrid vehicle 20, it may be mounted on a moving body other than a vehicle, or may be incorporated into stationary equipment.

[0062] The relationship between the main elements of the embodiment and the main elements of the invention described in the section on means for solving the problem will be described below. In the embodiment, the engine 22 corresponds to the "engine", the motor 30 corresponds to the "motor", the clutch K0 corresponds to the "clutch", and the HVECU 70, the engine ECU 24, and the motor ECU 34 correspond to the "control device".

[0063] The correspondence between the main elements of the Examples and the main elements of the invention described in the Summary of the Problem column does not limit the elements of the invention described in the Summary of the Problem column, since the Examples are examples for specifically explaining the mode for implementing the invention described in the Summary of the Problem column. In other words, the interpretation of the invention described in the Summary of the Problem column should be based on the description in that column, and the Examples are merely a specific example of the invention described in the Summary of the Problem column.

[0064] Although the form for carrying out the present invention has been described above using examples, the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be carried out in various forms without departing from the scope of the gist of the present invention. [Industrial Applicability]

[0065] The present invention can be used in the engine device manufacturing industry and the like. [Explanation of symbols]

[0066] 20 hybrid vehicle, 22 engine, 23 crankshaft, 24 engine ECU, 25 starter motor, 26 alternator, 30 motor, 30a rotational position sensor, 31 rotating shaft, 32 inverter, 34 motor ECU, 40 automatic transmission, 41 input shaft, 41a rotational speed sensor, 42 output shaft, 42a rotational speed sensor, 43 torque converter, 44 transmission input shaft, 44a rotational speed sensor, 45 automatic transmission, 48 differential gear, 49 drive wheel, 60 high voltage battery, 61 high voltage side power line, 62 low voltage battery, 63 low voltage side power line, 64 DC / DC converter, 70 HVECU, 80 ignition switch, 81 shift lever, 82 shift position sensor, 83 accelerator pedal, 84 accelerator pedal position sensor, 85 brake pedal, 86 Brake pedal position sensor, 87 vehicle speed sensor, 122 air cleaner, 123 intake pipe, 123a air flow meter, 123t temperature sensor, 124 throttle valve, 124a throttle valve position sensor, 125 surge tank, 125a pressure sensor, 126 port injection valve, 127 in-cylinder injection valve, 128 intake valve, 129 combustion chamber, 130 spark plug, 132 piston, 133 exhaust valve, 134 exhaust pipe, 135 purification device, 135a purification catalyst, 136 PM filter, 136a differential pressure sensor, 137 front air-fuel ratio sensor, 138 rear air-fuel ratio sensor, 140 crank position sensor, 142 water temperature sensor, 144 cam position sensor, K0 clutch.

Claims

【Claim 1】 An engine device comprising: an engine having a purification catalyst attached to an exhaust system; a motor connected to an output shaft of the engine via a clutch; and a control device configured to control the engine, the motor, and the clutch, wherein when the control device permits torque control for controlling the engine based on a required torque after starting fuel injection and ignition of the engine from a state in which fuel cut of the engine is being performed, the control device restricts the required torque when an elapsed time from complete combustion of the engine is less than a time threshold as compared with when the elapsed time is equal to or greater than the time threshold, the control device performs a first starting control for controlling the engine, the motor, and the clutch such that, in response to a starting request of the engine, the clutch is semi-engaged to crank the engine by the motor, fuel injection and ignition are started in a cylinder that first reaches top dead center of compression or a cylinder that secondarily reaches top dead center of compression, the clutch is then released so that a differential rotational speed between the rotational speed of the engine and the rotational speed of the motor decreases, and the clutch is engaged when the differential rotational speed reaches less than a predetermined differential rotational speed; and a second starting control for controlling the engine, the motor, and the clutch such that the clutch is semi-engaged to crank the engine by the motor, and fuel injection and ignition are started after the clutch is engaged when the differential rotational speed reaches less than the predetermined differential rotational speed, and the control device selects and executes one of a plurality of starting controls including the first starting control and the second starting control, the time threshold is set to be longer in the case of the second starting control than in the case of the first starting control, Engine device.

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