Hybrid vehicles

Abstract

To perform proper quick catalyst warmup control during idling-off.SOLUTION: During an idling-off in which an engine idling operation is not being indicated, when quick catalyst warmup for warming up a catalyst of a purification device is to be performed by operating an engine by making fuel injection at a compression stroke or an expansion stroke and retarding an ignition timing, the engine and a first electric motor are controlled so that the engine is operated at a first prescribed rotation number while outputting a prescribed torque, and a second electric motor is controlled so that a drive force based on a required drive force is output.SELECTED DRAWING: Figure 3

Description

[Technical field]

[0001] The present invention relates to a hybrid vehicle, and more particularly to a hybrid vehicle equipped with a first electric motor capable of generating electricity mechanically connected to the output shaft of an engine having a purification device attached to its exhaust system, and a second electric motor capable of inputting and outputting power for running. [Background technology]

[0002] Conventionally, as this type of technology, an engine device has been proposed that performs rapid catalyst warm-up to warm up the catalyst of a purification device attached to the exhaust system of the engine by injecting fuel during the compression stroke or expansion stroke and significantly retarding the ignition timing when the catalyst temperature is below the activation temperature and conditions such as accelerator off are met (see, for example, Patent Document 1). In this engine device, when rapid catalyst warm-up is being performed, feedback control is performed on the ignition timing based on the engine speed. [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Patent Publication No. 2021-175889 Summary of the Invention [Problem to be solved by the invention]

[0004] Rapid catalyst warm-up is usually performed when engine idling is instructed (idle on), but rapid catalyst warm-up cannot be performed when engine idling is not instructed (idle off) because the engine is generally operated under load. In a hybrid vehicle equipped with a first electric motor capable of generating electricity mechanically connected to the output shaft of an engine having a purification device attached to the exhaust system, and a second electric motor capable of inputting and outputting power for running, it is desirable to perform rapid catalyst warm-up even when the vehicle is in idle off because the vehicle can run using the second electric motor. However, the control of the engine and the first electric motor when the vehicle is in idle on is different from the control of the engine and the first electric motor when the vehicle is in idle off, so the rapid catalyst warm-up control when the vehicle is in idle on cannot be used as it is when the vehicle is in idle off.

[0005] A primary object of the hybrid vehicle of the present invention is to execute more appropriate rapid catalyst warm-up control during idle off. [Means for solving the problem]

[0006] The hybrid vehicle of the present invention employs the following means to achieve the above-mentioned main object.

[0007] The hybrid vehicle of the present invention is an engine having an in-cylinder injection valve and a purification device having a catalyst for purifying exhaust gas attached to an exhaust system; a first electric motor mechanically connected to an output shaft of the engine and capable of generating electricity; A second electric motor capable of inputting and outputting power for traveling; an electricity storage device capable of exchanging electric power with the first electric motor and the second electric motor; a control device that controls the engine, the first electric motor, and the second electric motor; A hybrid vehicle comprising: When performing rapid catalyst warm-up for warming up the catalyst of the purification device by operating the engine with fuel injection during a compression stroke or an expansion stroke and retarding the ignition timing during an idle-off state in which an idle operation of the engine is not instructed, the control device controls the engine and the first electric motor so that the engine is operated at a first predetermined rotation speed while outputting a predetermined torque, and controls the second electric motor so that a driving force based on a required driving force is output. It is characterized by:

[0008] In the hybrid vehicle of the present invention, when the engine is in an idle-off state where idling is not instructed, fuel is injected during the compression stroke or expansion stroke and the ignition timing is retarded to perform rapid catalyst warm-up to warm up the catalyst of the purification device. The engine and the first electric motor are controlled so that the engine is operated at a first predetermined rotation speed while outputting a predetermined torque, and the second electric motor is controlled so that a driving force based on a required driving force is output. This makes it possible to perform more appropriate rapid catalyst warm-up control during idle-off. In order to operate the engine at the first predetermined rotation speed while outputting a predetermined torque, the rotation speed of the first electric motor is controlled so that the engine is operated at the first predetermined rotation speed, and the air amount is controlled so that the engine outputs a predetermined torque.

[0009] In the hybrid vehicle of the present invention, when the rapid catalyst warm-up is performed during the idle-off state, the control device may perform a first feedback control using a proportional term and an integral term on the air amount and / or ignition timing of the engine using an estimated engine torque estimated based on the output torque of the first electric motor. The torque output from the engine when the rotation speed of the first electric motor is controlled so that the engine reaches a first predetermined rotation speed can be estimated from the torque output from the first electric motor. Therefore, feedback control can be performed on the air amount and ignition timing of the engine so that the estimated engine torque becomes a desired torque using the estimated engine torque estimated based on the output torque of the first electric motor. By performing such a first feedback control, the engine can be operated in a relatively stable state and rapid catalyst warm-up can be performed.

[0010] In the hybrid vehicle of the present invention in which the first feedback control is performed, the control device may perform the first feedback control so that the estimated engine torque becomes equal to or greater than the reference torque when the estimated engine torque falls below a reference torque that is smaller than the predetermined torque. In this way, the first feedback control is performed only when the estimated engine torque falls below the reference torque, so that excessive control can be avoided and the load on the control device can be reduced. Also, engine control that prioritizes exhaust reduction can be continued without disrupting the optimal balance between the amount of exhaust gas from the engine and the energy supplied to the catalyst.

[0011] In the hybrid vehicle of the present invention in which the first feedback control is performed, when the control device executes the rapid catalyst warm-up during idle-on when an instruction to idle the engine is given, the control device may control the engine and the first electric motor so that the engine operates autonomously at a second predetermined rotation speed, control the second electric motor so that a driving force based on a required driving force is output, and perform a second feedback control using a proportional term and an integral term for the air amount and / or ignition timing of the engine using the rotation speed of the engine. In this way, the engine can be kept in a relatively stable operating state even during idle-on, and rapid catalyst warm-up can be performed.

[0012] In the hybrid vehicle of the present invention in which first feedback control and second feedback control are performed, the control device may attenuate an integral term in the first feedback control when switching from idle off to idle on while the rapid catalyst warm-up is being performed, and attenuate an integral term in the second feedback control when switching from idle on to idle off while the rapid catalyst warm-up is being performed. In this case, the control device may attenuate the integral term of the feedback control for the air amount based on the intake air amount at that time, and attenuate the integral term of the feedback control for the ignition timing based on a mode predetermined for a plurality of states.

[0013] In the hybrid vehicle of the present invention in which the first feedback control is performed, the control device may prohibit the first feedback control when the rotation speed of the engine is increased by the first electric motor. In this case, the output torque of the first electric motor does not reflect the torque output from the engine, and therefore the first feedback control should not be performed.

[0014] In the hybrid vehicle of the present invention in which the first feedback control and the second feedback control are performed, the control device may hold the integral term of the feedback control for the ignition timing for a predetermined time when switching from the idle-off to the idle-on and from the idle-on to the idle-off during the execution of the rapid catalyst warm-up. In this way, a sudden change in the ignition timing can be suppressed.

[0015] In the hybrid vehicle of the present invention in which the first feedback control and the second feedback control are performed, when the feedback control is switched in association with switching from the idle-off to the idle-on and from the idle-on to the idle-off during the execution of the rapid catalyst warm-up, and the ignition timing is corrected in a direction different from the ignition timing base value after the switching, an integral term in the feedback control after the switching may be modified so that the ignition timing is corrected in the direction of the ignition timing base value. In this way, the ignition timing can be prevented from being corrected in a direction different from the ignition timing base value after the switching.

[0016] In the hybrid vehicle of the present invention in which the first feedback control and the second feedback control are performed, the control device may gradually change the ignition timing toward the ignition timing base value after the switching when the feedback control is switched from the idle-off to the idle-on and from the idle-on to the idle-off during the execution of the rapid catalyst warm-up. In this way, a sudden change in the ignition timing can be suppressed. In this case, the control device may gradually change the upper and lower limit guard values ​​toward the upper and lower limit guard values ​​after the switching when the feedback control is switched from the idle-off to the idle-on and from the idle-on to the idle-off during the execution of the rapid catalyst warm-up. In this way, a sudden change in the ignition timing due to the upper and lower limit guard values ​​after the switching can be avoided, even though the ignition timing is gradually changed toward the ignition timing base value after the switching. [Brief description of the drawings]

[0017] [Figure 1] FIG. 1 is a diagram showing an outline of the configuration of a hybrid vehicle 20 according to an embodiment of the present invention. [Diagram 2] FIG. 2 is a diagram showing an outline of the configuration of an engine 22. [Diagram 3] 4 is a flowchart showing an example of rapid catalyst warm-up control executed by an engine ECU 24, an HVECU 70, etc. [Figure 4] 5 is a flowchart of an example of a feedback control process for idle-on. [Diagram 5] 5 is a flowchart of an example of a feedback control process for idle off. [Figure 6] 10 is a flowchart illustrating an example of a process for starting feedback control for idle off. [Figure 7] FIG. 11 is an explanatory diagram showing an example of a time change of the estimated torque Test when the value 0 is used for both the threshold value Tref1 and the convergence torque Tref2 in the feedback control in the rapid catalyst warm-up control for idle off. [Figure 8] 10 is a flowchart showing an example of a switching time ignition timing process for switching the ignition timing Tp of the rapid catalyst warm-up control when switching between idle-on and idle-off. [Figure 9] FIG. 11 is an explanatory diagram showing an example of changes in the ignition timing Tp and the upper and lower limit guard values ​​Tlim when switching between idle on and idle off. [Figure 10] 10 is a flowchart showing an example of an air amount integral term attenuation amount setting process; [Figure 11] 10 is a flowchart showing an example of an ignition timing integral term attenuation amount setting process; [Figure 12] FIG. 2 is an explanatory diagram showing a list of an example of ignition timing feedback control modes and attenuation amounts Tatt. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0018] Next, a mode for carrying out the present invention will be described using examples. EXAMPLES

[0019] Fig. 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 according to an embodiment of the present invention, and Fig. 2 is a schematic diagram showing the configuration of an engine 22. As shown in Fig. 1, the hybrid vehicle 20 of the embodiment includes the 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.

[0020] The engine 22 is configured as a six-cylinder internal combustion engine that uses fuel such as gasoline or diesel and outputs 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 supplied from a fuel supply device 150 through a low-pressure supply pipe 153 into an intake port, and an in-cylinder injection valve 127 that injects fuel supplied from the fuel supply device 150 through a high-pressure supply pipe 158 into a cylinder. The in-cylinder injection valve 127 is disposed approximately at the center of the top of a combustion chamber 129 and injects fuel in a spray form. The spark plug 130 is disposed near the in-cylinder injection valve 127 so as to ignite the fuel sprayed in a spray form from the in-cylinder injection valve 127. The engine 22 has the port injection valve 126 and the in-cylinder injection valve 127, and can be operated in any one of a port injection mode, an in-cylinder injection mode, and a common injection mode. In the port injection mode, air purified by the air cleaner 122 is drawn into the intake pipe 123 and passes through the throttle valve 124 and the surge tank 125, while fuel is injected from the port injection valve 126 downstream of the surge tank 125 of the intake pipe 123 to mix the air and fuel. This mixture is then drawn into the combustion chamber 129 via the intake valve 128 and combusted explosively by an electric spark from the spark plug 130, and the reciprocating motion of the piston 132, which is pushed down by the energy of the mixture in the cylinder bore, 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 the fuel is combusted explosively by an electric spark from the spark plug 130 to obtain the rotational motion of the crankshaft 23. In the common 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 the compression stroke, and the fuel is exploded and burned 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 into the exhaust pipe 134 via the exhaust valve 133 is discharged into the outside air via a purification device 135.The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components in the exhaust gas, such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx).

[0021] The fuel supply device 150 is configured as a device that supplies fuel in a fuel tank 151 to a port injection valve 126 and an in-cylinder injection valve 127 of the engine 22. The fuel supply device 150 includes the fuel tank 151, a feed pump 152, a low-pressure supply pipe 153, a check valve 154, a relief pipe 155, a relief valve 156, a high-pressure pump 157, and a high-pressure supply pipe 158.

[0022] Feed pump 152 is configured as an electric pump that operates by receiving power from a battery (not shown), and is disposed in fuel tank 151. This feed pump 152 supplies fuel in fuel tank 151 to low-pressure supply pipe 153. Low-pressure supply pipe 153 is connected to port injection valve 126. Check valve 154 is provided in low-pressure supply pipe 153, and allows fuel to flow in the direction from feed pump 152 to port injection valve 126, while regulating fuel flow in the opposite direction.

[0023] Relief pipe 155 is connected to low-pressure supply pipe 153 and fuel tank 151. Relief valve 156 is provided in relief pipe 155, and closes when the fuel pressure in low-pressure supply pipe 153 is below threshold value Pflolim, and opens when the fuel pressure in low-pressure supply pipe 153 is equal to or higher than threshold value Pflolim. When relief valve 156 opens, a portion of the fuel in low-pressure supply pipe 153 is returned to fuel tank 151 via relief pipe 155. In this way, the fuel pressure in low-pressure supply pipe 153 is prevented from becoming excessive.

[0024] The high-pressure pump 157 is driven by power from the engine 22 (in this embodiment, the rotation of the intake camshaft that opens and closes the intake valve 128) and is configured as a pump that pressurizes fuel in the low-pressure supply pipe 153 and supplies it to the high-pressure supply pipe 158. The high-pressure pump 157 has an electromagnetic valve 157a connected to its intake port and opens and closes when pressurizing the fuel, a check valve 157b connected to its discharge port and restricts the backflow of fuel and maintains the fuel pressure in the high-pressure supply pipe 158, and a plunger 157c that is actuated (moves in the vertical direction in FIG. 1 ) by the rotation of the engine 22 (the rotation of the intake camshaft). When the engine 22 is operating, the high-pressure pump 157 draws in fuel from the low-pressure supply pipe 153 when the electromagnetic valve 157a is opened, and when the electromagnetic valve 157a is closed, the high-pressure pump 157 pressurizes the fuel to be supplied to the high-pressure supply pipe 158 by intermittently sending the fuel compressed by the plunger 157c to the high-pressure supply pipe 158 via the check valve 157b.

[0025] The operation of the engine 22 is controlled by an 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).

[0026] Signals from various sensors required for controlling the operation of the engine 22 are input to the engine ECU 24 via an input port. 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 coolant temperature Tw from a water temperature sensor 142 that detects the temperature of the coolant for 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 such a measurement 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 in the intake pipe 123, the intake air temperature Ta from a temperature sensor 123t attached upstream of the throttle valve 124 in the intake pipe 123, and the surge pressure Ps from a pressure sensor 125a attached to the surge tank 125. Other examples of such a measurement include a front air-fuel ratio AF1 from a front air-fuel ratio sensor 137 attached upstream of the purification device 135 in the exhaust pipe 134, and a rear air-fuel ratio AF2 from a rear air-fuel ratio sensor 138 attached between the purification device 135 and the PM filter 136 in the exhaust pipe 134. Other examples of such fuel pressure include the fuel temperature Tftnk from a fuel temperature sensor 151t attached to the fuel tank 151, the rotation speed Np of the feed pump 152 from a rotation speed sensor 152a attached to the feed pump 152, the low pressure fuel pressure (the pressure of the fuel supplied to the port injection valve 126) PL from a fuel pressure sensor 153p attached to the low pressure supply pipe 153 near the port injection valve 126 (e.g., a low pressure delivery pipe), and the high pressure fuel pressure (the pressure of the fuel supplied to the in-cylinder injection valve 127) PH from a fuel pressure sensor 158p attached to the high pressure supply pipe 158 near the in-cylinder injection valve 127 (e.g., a high pressure delivery pipe).

[0027] Various control signals for controlling the operation of the engine 22 are output from the engine ECU 24 via an output port. Examples of signals output from the engine ECU 24 include a control signal to the throttle valve 124, a control signal to the port injection valve 126, a control signal to the in-cylinder injection valve 127, a control signal to the ignition plug 130, and a control signal to a variable valve timing mechanism 139 that can change the opening and closing timing of the intake valve 128. Other examples include a control signal to the feed pump 152 of the fuel supply device 150 and a control signal to the electromagnetic valve 157a of the high-pressure pump 157.

[0028] 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.

[0029] As shown in Fig. 1, the planetary gear 30 is configured as a single pinion type planetary gear mechanism. A rotor of a motor MG1 is connected to a sun gear of the planetary gear 30. A drive shaft 36 that is connected to drive wheels 39a, 39b via a differential gear 38 is connected to a ring gear of the planetary gear 30. A crankshaft 23 of the engine 22 is connected to a carrier of the planetary gear 30.

[0030] The motor MG1 is configured, for example, as a synchronous generator motor, and as described above, its rotor is connected to the sun gear of the planetary gear 30. The motor MG2 is configured, for example, as a synchronous generator motor, and its rotor is connected to the drive shaft 36. The inverters 41, 42 are used to drive the motors MG1, MG2, and are connected to a battery 50 via a power line 54. The motors MG1, MG2 are rotationally driven by a motor electronic control unit (hereinafter referred to as "motor ECU") 40 controlling the switching of a plurality of switching elements (not shown) of the inverters 41, 42.

[0031] The motor ECU 40 includes a microcomputer having a CPU, ROM, RAM, flash memory, input / output ports, and communication ports (not shown). Signals from various sensors required for driving and controlling the motors MG1 and MG2 are input to the motor ECU 40 via the input ports. Examples of signals input to the motor ECU 40 include rotational positions θm1 and θm2 from rotational position sensors (not shown) that detect the rotational positions of the rotors of the motors MG1 and MG2, and phase currents Iu1, Iv1, Iu2, and Iv2 from current sensors (not shown) that detect the phase currents flowing through the phases of the motors MG1 and MG2. The motor ECU 40 outputs switching control signals and the like to a plurality of switching elements (not shown) of the inverters 41 and 42 via the output ports. The motor ECU 40 is connected to the HVECU 70 via a communication port. The motor ECU 40 calculates the electrical angles θe1, θe2 and rotation 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 sensors.

[0032] The battery 50 is configured as, for example, a lithium ion secondary battery or a nickel-hydrogen secondary battery, and as described above, is connected to the inverters 41, 42 via the power line 54. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as the "battery ECU") 52.

[0033] Although not shown, the battery ECU 52 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 required for managing the battery 50 are input to the battery ECU 52 via an input port. Examples of signals input to the battery ECU 52 include a voltage Vb of the battery 50 from a voltage sensor (not shown) attached between the terminals of the battery 50, a current Ib of the battery 50 from a current sensor (not shown) attached to an output terminal of the battery 50, and a temperature Tb of the battery 50 from a temperature sensor (not shown) attached to the battery 50. The battery ECU 52 is connected to the HVECU 70 via a communication port. The battery ECU 52 calculates a power storage ratio SOC of the battery 50 based on an integrated value of the current Ib of the battery 50 from the current sensor. The power storage ratio SOC is a ratio of the amount of power that can be discharged from the battery 50 to the total capacity of the battery 50.

[0034] 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 an ignition signal from an ignition switch 80 and a shift position SP from a shift position sensor 82 that detects the operation position of a shift lever 81. Other examples of signals input to the HVECU 70 include 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. 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.

[0035] In the hybrid vehicle 20 of the embodiment thus configured, the HVECU 70, the engine ECU 24, and the motor ECU 40 are controlled in a coordinated manner to basically switch between a hybrid driving mode (HV driving mode) in which the engine 22 is operated, and an electric driving mode (EV driving mode) in which the engine 22 is not operated, and the vehicle runs while operating the engine 22 intermittently.

[0036] In the HV driving mode, the HVECU 70 basically first sets a driving torque Td* required for driving (required of the drive shaft 36) based on the accelerator opening Acc and the vehicle speed V, and calculates a driving power Pd* required for driving by multiplying the set driving torque Td* by the rotation speed Nd of the drive shaft 36 (rotation speed Nm2 of the motor MG2). Next, the HVECU 70 sets a target power Pe* for the engine 22 based on the driving power Pd* and the charge storage rate SOC of the battery 50, and sets a target rotation speed Ne* and target torque Te* for the engine 22 and torque commands Tm1* and Tm2* for the motors MG1 and MG2 so that the target power Pe* is output from the engine 22 and the driving torque Td* is output to the drive shaft 36. The set target rotation speed Ne* and target torque Te* are sent to the engine ECU 24, and the torque commands Tm1* and Tm2* are sent to the motor ECU 40.

[0037] The engine ECU 24 performs operation control of the engine 22, such as intake air amount control, fuel injection control, ignition control, and opening / closing timing control, so that the engine 22 operates based on the target rotation speed Ne* and the target torque Te*. The intake air amount control is performed by controlling the opening of the throttle valve 124. The fuel injection control is performed by controlling the fuel injection amount from the port injection valve 126 and the in-cylinder injection valve 127 in the port injection mode, the in-cylinder injection mode, or the shared injection mode. The ignition control is performed by controlling the ignition timing of the spark plug 130. The motor ECU 40 performs switching control of a plurality of switching elements of the inverters 41, 42 so that the motors MG1, MG2 are driven by the torque commands Tm1*, Tm2*.

[0038] In the EV driving mode, the HVECU 70 sets the driving torque Td* in the same manner as in the HV driving mode, sets the torque command Tm1* of the motor MG1 to a value of 0, sets the torque command Tm2* of the motor MG2 so that the driving torque Td* is output to the drive shaft 36, and transmits the set torque commands Tm1* and Tm2* to the motor ECU 40. The control of the inverters 41 and 42 by the motor ECU 40 has been described above.

[0039] In the HV driving mode, when the target power Pe* falls below the power threshold Peref, it is determined that the stop condition for the engine 22 is satisfied, and the engine 22 is stopped and the driving mode is switched to the EV driving mode. In the EV driving mode, when the target power Pe* calculated in the same manner as in the HV driving mode falls above the power threshold (Peref+α), it is determined that the start condition for the engine 22 is satisfied, and the engine 22 is started and the driving mode is switched to the HV driving mode.

[0040] In the hybrid vehicle 20 of the embodiment, catalyst warm-up is performed on the purification catalyst (three-way catalyst) 135a of the purification device 135 attached to the exhaust pipe 134 of the engine 22. The catalyst warm-up of the purification device 135 is performed when the condition that the catalyst temperature Tc is equal to or lower than a predetermined temperature below the temperature at which the catalyst is activated or the accelerator is off is satisfied. There are two types of catalyst warm-up: normal catalyst warm-up and rapid catalyst warm-up. The normal catalyst warm-up is performed by maintaining the rotation speed Ne of the engine 22 at a predetermined rotation speed Nset (e.g., 1300 rpm, etc.), injecting fuel from the in-cylinder injection valve 127 once to three times during the intake stroke to homogenize the mixture in the combustion chamber 129, and retarding the ignition timing from the normal timing to perform explosive combustion (homogeneous combustion). Rapid catalyst warm-up is performed by maintaining the rotation speed Ne of the engine 22 at a predetermined rotation speed Nset (for example, 1300 rpm, etc.), injecting fuel from the in-cylinder injection valve 127 during the intake stroke, and also performing the final fuel injection during the compression stroke to increase the fuel concentration of the mixture in the combustion chamber 129 near the ignition plug 130, and retarding the ignition timing further than in normal catalyst warm-up to perform explosive combustion (stratified combustion). Since retarding the ignition timing reduces the combustion efficiency, the amount of intake air is increased to maintain the rotation speed Ne of the engine 22, while the amount of combustion gas increases, which increases the absolute amount of emission components, but promotes catalyst warm-up. Therefore, rapid catalyst warm-up can further promote catalyst warm-up by further retarding the ignition timing compared to normal catalyst warm-up. In addition, with rapid catalyst warm-up, fuel is injected one to three times during the intake stroke and compression stroke, and the final fuel injection is performed during the expansion stroke. In some cases, the fuel is ignited in synchronization with the fuel injection during the expansion stroke, resulting in explosive combustion (stratified charge combustion).

[0041] Next, the operation of the hybrid vehicle 20 of the embodiment configured as described above, in particular the operation when the rapid catalyst warm-up control is being executed, will be described. FIG 3 is a flowchart showing an example of the rapid catalyst warm-up control executed by the engine ECU 24 and the HVECU 70.

[0042] When the rapid catalyst warm-up control is executed, first, it is determined whether or not an idle operation of the engine 22 is instructed (idle on or idle off) (step S100). If it is determined that the engine 22 is idle on, the rapid catalyst warm-up control for idle on is executed (step S110), and if it is determined that the engine 22 is idle off, the rapid catalyst warm-up control for idle off is executed (step S120), and this process ends.

[0043] The rapid catalyst warm-up control for idle-on is performed by controlling the engine 22 to operate autonomously so that the engine speed Ne of the engine 22 becomes a predetermined speed Nset, and by injecting fuel from the in-cylinder injection valve 127 in multiple times during the intake stroke, compression stroke, or expansion stroke, and by retarding the ignition timing Tp further than that for normal catalyst warm-up to perform explosive combustion (stratified combustion). At this time, the autonomous operation of the engine 22 is controlled by feedback-controlling the ignition timing Tp and the air amount (intake air amount) Qa with respect to the engine speed Ne of the engine 22. A flowchart of an example of feedback control processing for idle-on is shown in FIG.

[0044] In the feedback control process for idle-on, first, the rotation speed Ne of the engine 22 is input (step S200), the ignition timing Tp is controlled by the relational expression in the feedback control of the ignition timing Tp shown in the following equation (1) (step S210), and the air amount Qa is controlled by the relational expression in the feedback control of the air amount Qa shown in the following equation (2) (step S220), and this process is terminated. In equation (1), "Tbase1" is the ignition timing base value in the rapid catalyst warm-up control for idle-on, "k11" is a constant of the proportional term, and "k12" is a constant of the integral term. The ignition timing base value Tbase1 in the rapid catalyst warm-up control for idle-on is a base value further retarded than the ignition timing in the normal catalyst warm-up control. In equation (2), "Qbase1" is the air amount base value in the rapid catalyst warm-up control for idle-on, "k13" is a constant of the proportional term, and "k14" is a constant of the integral term. The air amount base value Qbase1 is the amount of air required for the engine 22 to operate autonomously at a predetermined rotation speed Nset with the ignition timing Tp set to the ignition timing base value Tbase1, and can be obtained by experiment, machine learning, etc. When the air amount Qa is obtained, the throttle opening TH is adjusted so that the intake air amount becomes the air amount Qa.

[0045]

number

[0046] Rapid catalyst warm-up control for idle-off is performed by controlling the engine 22 and the motor MG1 so that the rotation speed Ne of the engine 22 reaches a predetermined rotation speed Nset and a predetermined torque (e.g., 20 Nm or 30 Nm) Tset is output from the engine 22, and by injecting fuel from the in-cylinder injection valve 127 in multiple injections during the intake stroke, compression stroke, or expansion stroke, and by retarding the ignition timing Tp further than in normal catalyst warm-up to perform explosive combustion (stratified charge combustion). At this time, the engine 22 outputs power of the predetermined rotation speed Nset x predetermined torque Tset. This power (Nset x Tset) is used as the target power Pe* to be output from the engine 22 in the drive control of the HV driving mode described above. If the engine 22 outputs power (Nset x Tset), the torque command Tm1* of the motor MG1 is set to a value calculated by the following formula (3), and the torque command Tm2* of the motor MG2 is calculated so that the driving torque Td* is output to the drive shaft 36. By controlling the engine 22 and the motors MG1 and MG2, the vehicle can run while outputting the driving torque Td* while executing the rapid catalyst warm-up control for idle-off. Here, in formula (3), "ρ" is the gear ratio of the planetary gear 30 (the number of teeth of the sun gear / the number of teeth of the ring gear). The torque command Tm1* of the motor MG1 is not determined by the above formula (3) because feedback control is executed so that the engine 22 is operated at the predetermined rotation speed Nset. In addition, in the idle-off rapid catalyst warm-up control, feedback control is performed on the ignition timing Tp and the air amount (intake air amount) Qa for the estimated torque Test output from the engine 22, which is calculated based on the torque Tm1 output from the motor MG1, to control the engine 22. A flowchart of an example of the feedback control process for idle-off is shown in Fig. 5, and a flowchart of an example of the start process of the feedback control for idle-off is shown in Fig. 6. For ease of explanation, the start process of the feedback control for idle-off will be explained first, and then the feedback control process for idle-off will be explained.

[0047]

number

[0048] When the process of starting feedback control for idle-off is executed, first, the torque Tm1 of the motor MG1 is input (step S400). For the torque Tm1 of the motor MG1, for example, a torque command Tm1* of the motor MG1 set by the HVECU 70 can be used. Next, an estimated torque Test estimated to be output from the engine 22 based on the torque Tm1 of the motor MG1 is calculated (step S410). The estimated torque Test can be obtained by the following equation (4). In equation (4), "ρ" is the gear ratio of the planetary gear 30 (number of teeth of the sun gear / number of teeth of the ring gear).

[0049]

number

[0050] Next, it is determined whether the estimated torque Test is less than a threshold value Tref1 (step S420). The threshold value Tref1 is set as the output torque of the engine 22 to be maintained during rapid catalyst warm-up during idle-off, and may be, for example, a predetermined torque Tset or a value smaller than the predetermined torque Tset, for example, 10 Nm, 5 Nm, 0 Nm, etc. In other words, any torque that allows rapid catalyst warm-up may be used. When it is determined that the estimated torque Test is equal to or greater than the threshold value Tref1, it is determined that rapid catalyst warm-up is possible, and this process is terminated. On the other hand, when it is determined that the estimated torque Test is less than the threshold value Tref1, it is determined that feedback control for idle-off is necessary, and feedback control for idle-off is started (step S430), and this process is terminated.

[0051] When the feedback control for idle-off is started, the feedback control process for idle-off shown in FIG. 5 is repeatedly executed. When the feedback control process for idle-off is executed, first, the rotation speed Ne of the engine 22 is input (step S300). Next, the rotation speed Ne input when this process was executed last time (hereinafter referred to as the previous rotation speed Ne) is subtracted from the input rotation speed Ne to calculate the rotation speed change amount ΔN (ΔN=Ne-previous Ne) (step S310), and it is determined whether the rotation speed change amount ΔN is less than a threshold value Nref (step S320). The threshold value Nref is a threshold value for determining whether the rotation speed Ne of the engine 22 is increased by the motor MG1, and is determined by the frequency of repetition of the feedback control process for idle-off. When it is determined that the rotation speed change amount ΔN is equal to or greater than the threshold value Nref, it is determined that the rotation speed Ne of the engine 22 is increased by the motor MG1, and therefore the estimated torque Test output from the engine 22 based on the torque Tm1 of the motor MG1 should not be estimated, and this process is terminated.

[0052] On the other hand, when it is determined in step S320 that the rotation speed change amount ΔN is less than the threshold value Nref, the torque Tm1 of the motor MG1 is input (step S330), the estimated torque Test estimated to be output from the engine 22 is calculated by the above-mentioned formula (4) (step S340), the ignition timing Tp is controlled by the relational expression in the feedback control of the ignition timing Tp shown in the following formula (5) using the estimated torque Test (step S350), and the air amount Qa is controlled by the relational expression in the feedback control of the air amount Qa shown in the following formula (6) (step S360), and this process ends. In formula (5), "Tbase2" is the ignition timing base value in the rapid catalyst warm-up control for idle off, "k21" is a constant of the proportional term, and "k22" is a constant of the integral term. The ignition timing base value Tbase2 in the rapid catalyst warm-up control for idle off is a value further retarded than the ignition timing base value Tbase1 in the rapid catalyst warm-up control for idle on, but the same value may be used. In formula (6), "Qbase2" is an air amount base value in the rapid catalyst warm-up control for idle-off, "k23" is a constant of the proportional term, and "k24" is a constant of the integral term. The air amount base value Qbase1 is an air amount required to output a predetermined torque Tset from the engine 22 with the engine 22 at a predetermined rotation speed Nset and the ignition timing Tp set to the ignition timing base value Tbase2, and can be obtained by experiments, machine learning, or the like. Furthermore, "Tref2" in formulas (5) and (6) is a torque at which the estimated torque Test should converge (hereinafter referred to as the convergence torque Tref2), and a value equal to or greater than the threshold value Tref1 and equal to or less than the predetermined torque Tset is used. Therefore, during idle-off, feedback control is started when the estimated torque Test falls below the threshold value Tref1, and the estimated torque Test is controlled to become the convergence torque Tref2. At this time, if the convergence torque Tref2 is set to be the same as the threshold value Tref1, feedback control is started when the estimated torque Test falls below the threshold value Tref1, and the estimated torque Test is controlled to become the threshold value Tref1 (convergence torque Tref2).

[0053]

number

[0054] 7 is an explanatory diagram showing an example of a time change of the estimated torque Test in the feedback control of the rapid catalyst warm-up control for idle off when the threshold value Tref1 and the convergence torque Tref2 are both set to 0. At time T1, the motor MG1 outputs a cranking torque to start the engine 22, and at time T2, the engine 22 outputs a predetermined torque Tset when the engine speed Ne becomes a predetermined speed Nset, and the rapid catalyst warm-up control for idle off is started. Thereafter, at time T3 when the estimated torque Test falls below the threshold value Tref1 (value 0), the feedback control in the rapid catalyst warm-up control for idle off is started, and at time T4, the estimated torque Test converges to the convergence torque Tref2 (value 0).

[0055] As described above, in the hybrid vehicle 20 of the embodiment, the idle-on rapid catalyst warm-up control is executed during the idle-on state, and the idle-off rapid catalyst warm-up control, which is different from the idle-on rapid catalyst warm-up control, is executed during the idle-off state. As a result, more appropriate rapid catalyst warm-up control can be executed during the idle-off state.

[0056] In the hybrid vehicle 20 of the embodiment, when the idle-off rapid catalyst warm-up control is executed, the feedback control in the idle-off rapid catalyst warm-up control is started when the estimated torque Test becomes less than the threshold value Tref1. However, the feedback control may be started simultaneously with the idle-off rapid catalyst warm-up control or after a predetermined time has elapsed. In this case, it is preferable that the convergence torque Tref2 is the same as the predetermined torque Tset.

[0057] Next, the switching operation of the ignition timing Tp when switching to the rapid catalyst warm-up control for idle-off due to the idle-off being turned on while the rapid catalyst warm-up control for idle-on is being executed will be described, and the switching operation of the ignition timing Tp when switching to the rapid catalyst warm-up control for idle-on due to the idle-on being turned on while the rapid catalyst warm-up control for idle-off is being executed will be described. Fig. 8 is a flowchart showing an example of the switching time ignition timing process executed when switching between the ignition timing Tp of the rapid catalyst warm-up control for idle-on and the ignition timing Tp of the rapid catalyst warm-up control for idle-off.

[0058] When the switching ignition timing process is executed, it is first determined whether the switching is from idle-on to idle-off or from idle-off to idle-on (step S500).

[0059] When it is determined that the switching is from idle on to idle off, it is determined whether or not a first predetermined time has elapsed since switching from idle on to idle off (step S510), and when it is determined that the first predetermined time has not elapsed, the integral term of the feedback control in the rapid catalyst warm-up control for idle on and the integral term of the feedback control in the rapid catalyst warm-up control for idle off are held (step S515).As the first predetermined time, the time required to switch the torque Tm1 of the motor MG1 from the torque at idle on to the torque at idle off in association with switching from idle on to idle off can be used.

[0060] Next, it is determined whether a second predetermined time has elapsed since switching from idle on to idle off (step S520), and if it is determined that the second predetermined time has not elapsed, the integral term of the feedback control in the rapid catalyst warm-up control for idle on is held (step S525). As the second predetermined time, the time required for the intake air amount Qa and the load factor KL to stabilize in response to the change in the throttle opening caused by switching from idle on to idle off can be used. The second predetermined time may be longer or shorter than the first predetermined time depending on the characteristics of the engine 22, etc.

[0061] In addition, it is determined whether or not both the first and second predetermined times have elapsed since switching from idle on to idle off (step S530), and if it is determined that both the first and second predetermined times have elapsed, the decay of the integral term of the feedback control in the rapid catalyst warm-up control for idle on is started (step S535). That is, the third term on the right side in the above-mentioned equations (1) and (2) is decayed toward the value 0. The amount of decay will be described later. If it is determined in step S530 that both the first and second predetermined times have not elapsed, the process returns to the process of determining whether or not the first predetermined time has elapsed since switching from idle on to idle off in step S510.

[0062] The processing of steps S510 to S535 is a processing in which the integral term of the feedback control in the rapid catalyst warm-up control for idle on is held until both the first predetermined time and the second predetermined time have elapsed and then decayed, and the integral term of the feedback control in the rapid catalyst warm-up control for idle off is held until the first predetermined time has elapsed.

[0063] When the first and second predetermined times have passed since switching from idle-on to idle-off and the integral term of the feedback control in the idle-on rapid catalyst warm-up control starts to decay, the current ignition timing Tp is retarded by the ignition timing gradual change amount ΔTp and set as the provisional ignition timing Tptmp (step S540). In the figure, the retard direction is expressed as negative, Tptmp=Tp-ΔTp. The ignition timing gradual change amount ΔTp is the amount of change when the ignition timing Tp is changed little by little. Then, the provisional ignition timing Tptmp and the previous ignition timing Tp are subtracted from the ignition timing base value Tbase2 of the idle-off rapid catalyst warm-up control to calculate the first ignition timing change amount ΔTp1 and the second ignition timing change amount ΔTp2 (step S550), and it is determined whether the absolute value of the first ignition timing change amount ΔTp1 is equal to or greater than the absolute value of the second ignition timing change amount ΔTp2 (step S560). This determination is made as to whether or not the tentative ignition timing Tptmp has changed toward the ignition timing base value Tbase2 compared to the previous ignition timing Tp.

[0064] When it is determined in step S560 that the absolute value of the first ignition timing change amount ΔTp1 is equal to or greater than the absolute value of the second ignition timing change amount ΔTp2, it is determined that the tentative ignition timing Tptmp has not changed toward the ignition timing base value Tbase2, and the sign of the ignition timing gradual change amount ΔTp is changed to reset the tentative ignition timing Tptmp (step S570). When the tentative ignition timing Tptmp is reset in this manner, the tentative ignition timing Tptmp is set as the ignition timing Tp (step S580), and the upper and lower limit guard values ​​Tlim of the ignition timing Tp are retarded by the ignition timing gradual change amount ΔTp (step S590). Then, it is determined whether the gradual change of the ignition timing Tp has been completed (step S595), and when it is determined that the gradual change of the ignition timing Tp has not been completed, the process returns to the process of determining whether a predetermined time has elapsed since the start of switching from idle on to idle off in step S520. Therefore, the process of steps S520 to S595 is repeatedly executed until the gradual change of the ignition timing Tp is completed, and each time the process is repeated, the ignition timing Tp is retarded by the ignition timing gradual change amount ΔTp toward the ignition timing base value Tbase2, and the upper and lower limit guard value Tlim is retarded by the ignition timing gradual change amount ΔTp toward the upper and lower limit guard value Tlim2 of the ignition timing Tp in the rapid catalyst warm-up control for idle-off. The completion of the gradual change of the ignition timing Tp can be determined by determining whether or not the difference between the ignition timing Tp and the ignition timing base value Tbase2 is less than the ignition timing change amount ΔTp. The upper and lower limit guard value Tlim2 is a value that is determined in advance so that the ignition timing Tp should not be advanced or retarded further in the rapid catalyst warm-up control for idle-off, and in the embodiment, a value advanced or retarded by a predetermined angle from the ignition timing base value Tbase2 in the rapid catalyst warm-up control for idle-off is used.

[0065] When it is determined in step S560 that the absolute value of the first ignition timing change amount ΔTp1 is less than the absolute value of the second ignition timing change amount ΔTp2, it is determined that the tentative ignition timing Tptmp is changing toward the ignition timing base value Tbase2, and the tentative ignition timing Tptmp is set as the ignition timing Tp (step S580). Then, the upper and lower limit guard values ​​Tlim of the ignition timing Tp are retarded by the ignition timing gradual change amount ΔTp (step S590), and it is determined whether the gradual change of the ignition timing Tp is completed (step S595). When it is determined that the gradual change of the ignition timing Tp is not completed, the process returns to the process of determining whether a predetermined time has elapsed since the start of switching from idle on to idle off in step S520. In this case, too, steps S520 to S595 are repeatedly executed until the gradual change of the ignition timing Tp is completed. Each time the process is repeated, the ignition timing Tp is retarded by the ignition timing gradual change amount ΔTp toward the ignition timing base value Tbase2, and the upper and lower limit guard values ​​Tlim are retarded by the ignition timing gradual change amount ΔTp toward the lower limit guard value Tlim2 of the ignition timing Tp in the rapid catalyst warm-up control for idle off.

[0066] When it is determined in step S500 that the switching is from idle off to idle on, it is determined whether or not a first predetermined time has elapsed since switching from idle off to idle on (step S610), and when it is determined that the first predetermined time has not elapsed, the integral term of the feedback control in the rapid catalyst warm-up control for idle on and the integral term of the feedback control in the rapid catalyst warm-up control for idle off are held (step S615). As the first predetermined time, a time required to switch the torque Tm1 of the motor MG1 from the torque at idle off to the torque at idle on accompanying switching from idle off to idle on can be used, and may be the same as the first predetermined time in step S510 described above, or may be a different time.

[0067] Next, it is determined whether a second predetermined time has elapsed since switching from idle off to idle on (step S620), and if it is determined that the second predetermined time has not elapsed, the integral term of the feedback control in the rapid catalyst warm-up control for idle off is held (step S625). As the second predetermined time, the time required for the intake air amount Qa and the load factor KL to stabilize in response to the change in the throttle opening degree that occurs when switching from idle off to idle on can be used, and may be the same as the second predetermined time in step S520 described above, or may be a different time. Note that this second predetermined time may also be longer or shorter than the first predetermined time depending on the characteristics of the engine 22, etc.

[0068] In addition, it is determined whether or not both the first and second predetermined times have elapsed since switching from idle-off to idle-on (step S630), and if it is determined that both the first and second predetermined times have elapsed, the decay of the integral term of the feedback control in the rapid catalyst warm-up control for idle-off is started (step S635). That is, the third term on the right side in the above-mentioned equations (5) and (6) is decayed toward the value 0. The amount of decay in this case will also be described later. If it is determined in step S630 that both the first and second predetermined times have not elapsed, the process returns to the process of determining whether or not the first predetermined time has elapsed since switching from idle-off to idle-on in step S610.

[0069] The processing of steps S610 to S635 is a processing in which the integral term of the feedback control in the rapid catalyst warm-up control for idle off is held until both the first predetermined time and the second predetermined time have elapsed and then decayed, and the integral term of the feedback control in the rapid catalyst warm-up control for idle on is held until the first predetermined time has elapsed.

[0070] When the first and second predetermined times have passed since switching from idle-off to idle-on and the integral term of the feedback control in the idle-off rapid catalyst warm-up control starts to decay, the current ignition timing Tp is advanced by the ignition timing gradual change amount ΔTp and set as the provisional ignition timing Tptmp (step S640). In the figure, the advance direction is expressed as plus, Tptmp=Tp+ΔTp. Then, the provisional ignition timing Tptmp and the previous ignition timing Tp are subtracted from the ignition timing base value Tbase1 of the idle-on rapid catalyst warm-up control to calculate the first ignition timing change amount ΔTp1 and the second ignition timing change amount ΔTp2 (step S650), and it is determined whether the absolute value of the first ignition timing change amount ΔTp1 is equal to or greater than the absolute value of the second ignition timing change amount ΔTp2 (step S660). This determination is made as to whether or not the tentative ignition timing Tptmp has changed toward the ignition timing base value Tbase1 compared to the previous ignition timing Tp.

[0071] When it is determined in step S660 that the absolute value of the first ignition timing change amount ΔTp1 is equal to or greater than the absolute value of the second ignition timing change amount ΔTp2, it is determined that the tentative ignition timing Tptmp has not changed toward the ignition timing base value Tbase1, and the sign of the ignition timing gradual change amount ΔTp is changed to reset the tentative ignition timing Tptmp (step S670). When the tentative ignition timing Tptmp is reset in this manner, the tentative ignition timing Tptmp is set as the ignition timing Tp (step S680), and the upper and lower limit guard values ​​Tlim of the ignition timing Tp are advanced by the ignition timing gradual change amount ΔTp (step S690). Then, it is determined whether the gradual change of the ignition timing Tp has been completed (step S695), and when it is determined that the gradual change of the ignition timing Tp has not been completed, the process returns to the process of determining whether a predetermined time has elapsed since the start of switching from idle off to idle on in step S620. Therefore, the process of steps S620 to S695 is repeatedly executed until the gradual change of the ignition timing Tp is completed, and each time the process is repeated, the ignition timing Tp advances toward the ignition timing base value Tbase1 by the ignition timing gradual change amount ΔTp, and the upper and lower limit guard value Tlim advances toward the upper and lower limit guard value Tlim1 of the ignition timing Tp in the rapid catalyst warm-up control for idle-on by the ignition timing gradual change amount ΔTp. The completion of the gradual change of the ignition timing Tp can be determined based on whether or not the difference between the ignition timing Tp and the ignition timing base value Tbase1 is less than the ignition timing change amount ΔTp. The upper and lower limit guard value Tlim1 is a value that is determined in advance so that the ignition timing Tp should not be advanced or retarded further in the rapid catalyst warm-up control for idle-on, and in the embodiment, a value advanced or retarded by a predetermined angle from the ignition timing base value Tbase1 in the rapid catalyst warm-up control for idle-on is used.

[0072] When it is determined in step S660 that the absolute value of the first ignition timing change amount ΔTp1 is less than the absolute value of the second ignition timing change amount ΔTp2, it is determined that the tentative ignition timing Tptmp is changing toward the ignition timing base value Tbase1, and the tentative ignition timing Tptmp is set as the ignition timing Tp (step S680). Then, the upper and lower limit guard values ​​Tlim of the ignition timing Tp are advanced by the ignition timing gradual change amount ΔTp (step S690), and it is determined whether the gradual change of the ignition timing Tp is complete (step S695). When it is determined that the gradual change of the ignition timing Tp is not complete, the process returns to the process of determining whether a predetermined time has elapsed since the start of switching from idle on to idle off in step S620. In this case, steps S620 to S695 are repeated until the gradual change of the ignition timing Tp is completed. Each time the process is repeated, the ignition timing Tp advances by the ignition timing gradual change amount ΔTp toward the ignition timing base value Tbase1, and the upper and lower limit guard values ​​Tlim advance by the ignition timing gradual change amount ΔTp toward the upper and lower limit guard values ​​Tlim1 of the ignition timing in the rapid catalyst warm-up control for idle-on.

[0073] FIG. 9 is an explanatory diagram showing an example of how the ignition timing Tp and the upper and lower limit guard values ​​Tlim change when switching between idle on and idle off. In the figure, the thick solid line indicates the ignition timing Tp, the thick dashed line indicates the upper and lower limit guard values ​​Tlim, the thick broken line indicates the ignition timing Tp of the comparative example, and the thin dashed line indicates the upper and lower limit guard values ​​Tlim1, Tlim2. In the comparative example, the ignition timing Tp changes gradually, but the upper and lower limit guard values ​​Tlim do not change gradually. In the figure, the upward direction indicates the advancement of the ignition timing Tp, and the downward direction indicates the retardation of the ignition timing Tp. Consider switching from idle on to idle off (upper part of the figure). In the comparative example, at time T1 when the air amount Qa becomes stable after both the first and second predetermined times have elapsed since switching from idle-on to idle-off, the upper limit guard value Tlim2 (the upper limit guard value of the ignition timing base value Tbase2) in the rapid catalyst warm-up control for idle-off is immediately used for guard processing, so the ignition timing Tp suddenly changes to the upper limit guard value Tlim2. In the embodiment, the ignition timing Tp and the upper and lower limit guard values ​​Tlim are gradually retarded from time T1 when the air amount Qa becomes stable. Then, at time T2 when the gradual change of the ignition timing Tp ends, the ignition timing Tp becomes the ignition timing base value Tbase2 in the rapid catalyst warm-up control for idle-off, and the upper and lower limit guard values ​​Tlim also become the upper and lower limit guard values ​​Tlim2 in the rapid catalyst warm-up control for idle-off. Next, switching from idle-off to idle-on (lower part of the figure) is considered. In the comparative example, immediately after time T1, guard processing is performed using the lower limit guard value Tlim1 (the lower limit guard value of the ignition timing base value Tbase1) in the idle-on rapid catalyst warm-up control, so that the ignition timing Tp suddenly changes to the lower limit guard value Tlim1. In the embodiment, the ignition timing Tp and the upper and lower limit guard values ​​Tlim are gradually advanced from time T1. Then, at time T2 when the gradual change of the ignition timing Tp ends, the ignition timing Tp becomes the ignition timing base value Tbase1 in the idle-on rapid catalyst warm-up control, and the upper and lower limit guard values ​​Tlim also become the upper and lower limit guard values ​​Tlim1 in the idle-on rapid catalyst warm-up control. In this way, by gradually changing the upper and lower limit guard values ​​Tlim together with the gradual change of the ignition timing Tp, a sudden change of the ignition timing Tp can be suppressed.

[0074] Next, the attenuation amount in the attenuation of the integral term in steps S535 and S635 of the switching ignition timing process in Fig. 8 will be described. Fig. 10 is a flowchart showing an example of an air amount integral term attenuation amount setting process executed when setting the attenuation amount of the integral term of the relational expression in the feedback control of the air amount Qa (the third term on the right side of the formula (2) and formula (6)), and Fig. 11 is a flowchart showing an example of an ignition timing integral term attenuation amount setting process executed when setting the attenuation amount of the integral term of the relational expression in the feedback control of the ignition timing Tp (the third term on the right side of the formula (1) and formula (5)). The following will explain each in order.

[0075] In the air amount integral term attenuation amount setting process, the intake air amount Qa of the engine 22 at that time is input (step S700), and the attenuation amount Qatt of the integral term (the third term on the right side of equations (2) and (6)) of the relational expression in the feedback control of the air amount Qa is set based on the intake air amount Qa (step S710), and this process ends. In this embodiment, the attenuation amount Qatt is set so that the greater the intake air amount Qa, the greater the attenuation amount Qatt. This is based on the fact that the greater the intake air amount Qa, the greater the amount of energy and the greater the warm-up of the engine 22.

[0076] In the ignition timing integral term attenuation amount setting process, the current ignition timing feedback control mode is determined (step S800), a value corresponding to the ignition timing feedback control mode is set as the attenuation amount Tatt (step S810), and this process ends. FIG. 12 shows an example of the ignition timing feedback control modes and the attenuation amount Tatt. Mode 1 is a mode in a normal state, that is, a mode in a state in which the idle-on rapid catalyst warm-up control and the idle-off rapid catalyst warm-up control are stably executed, and a normal value Tat1 (a value for active attenuation) is used as the attenuation amount Tatt. The value Tat1 can be appropriately determined by experiments, machine learning, or the like. Mode 0 is a mode in a state in which the idle-on rapid catalyst warm-up control and the idle-off rapid catalyst warm-up control are temporarily suspended, and the value Tat0 is used as the attenuation amount Tatt. In mode 0, the warm-up of the engine 22 progresses, so a value for relatively active attenuation is used as the value Tat0, and a value equal to or slightly smaller than the value Tat1 is used. Mode 2 is a mode in which feedback control cannot be performed for the ignition timing Tp immediately after switching from idle on to idle off, and a value of 0 is used as the attenuation amount Tatt. That is, in mode 2, the integral term is maintained. Mode 3 is a mode in which the combustion of the engine 22 is deteriorated (in idle on, the rotation speed Ne of the engine 22 is reduced, and in idle off, the estimated torque Test of the engine 22 estimated from the torque Tm1 of the motor MG1 is reduced), and feedback control is desired but the integral term is not desired to be updated (combustion deterioration (1)), and a value of 0 is used as the attenuation amount Tatt. Mode 4 is a mode in which the combustion of the engine 22 is deteriorated like in mode 3, but the integral term can also be updated (combustion deterioration (2)), and a value of Tat4 is used as the attenuation amount Tatt. Since the value Tat4 is not actively attenuated in mode 4, a value smaller than the value Tat1 is used. By changing the attenuation amount Tatt in accordance with the mode of the ignition timing feedback control in this manner, it is possible to more appropriately attenuate the integral term of the relational expression in the feedback control of the ignition timing Tp in the rapid catalyst warm-up control.

[0077] In the hybrid vehicle 20 of the embodiment described above, when the vehicle is in an idle-on state, the rapid catalyst warm-up control for idle-on is executed, and when the vehicle is in an idle-off state, the rapid catalyst warm-up control for idle-off, which is different from the rapid catalyst warm-up control for idle-on, is executed. As a result, the rapid catalyst warm-up control can be executed more appropriately when the vehicle is in an idle-off state.

[0078] In the hybrid vehicle 20 of the embodiment, when the idle-off rapid catalyst warm-up control is executed, feedback control is performed on the air amount Qa and ignition timing Tp of the engine 22 using the estimated torque Test of the engine 22 estimated based on the torque T1 of the motor MG1. This allows the engine to be in a relatively stable operating state and allows the idle-off rapid catalyst warm-up control to be executed. In addition, when the estimated torque Test becomes less than the threshold value Tref1, feedback control is performed so that the estimated torque Test becomes the convergence torque Tref2. This allows feedback control to be performed only when the estimated torque Test becomes less than the threshold value Tref1, and makes it possible to avoid excessive control. In addition, it is possible to continue the control of the engine 22 that prioritizes exhaust reduction without disrupting the optimal balance between the amount of exhaust gas from the engine 22 and the energy supplied to the catalyst.

[0079] In the hybrid vehicle 20 of the embodiment, when the rotation speed Ne of the engine 22 is increased by the motor MG1 during execution of the rapid catalyst warm-up control for idle-off, feedback control based on the estimated torque Test of the engine 22 is not performed (prohibited). This makes it possible to prevent the rotation speed Ne of the engine 22 from becoming unstable due to the feedback control being performed when the rotation speed Ne of the engine 22 is increased by the motor MG1.

[0080] In the hybrid vehicle 20 of the embodiment, when the rapid catalyst warm-up control for idle-on is switched to the rapid catalyst warm-up control for idle-off, or when the rapid catalyst warm-up control for idle-off is switched to the rapid catalyst warm-up control for idle-on, the integral term of the feedback control for the ignition timing Tp is held until the first predetermined time or the second predetermined time has elapsed. This makes it possible to suppress a sudden change in the ignition timing Tp.

[0081] In the hybrid vehicle 20 of the embodiment, when switching from the rapid catalyst warm-up control for idle-on to the rapid catalyst warm-up control for idle-off, or conversely, when switching from the rapid catalyst warm-up control for idle-off to the rapid catalyst warm-up control for idle-on, if the tentative ignition timing Tptmp advanced or retarded by the ignition timing gradual variation amount ΔTp from the ignition timing Tp does not change toward the ignition timing base values ​​Tbase1, Tbase2 in the control after the switching, the sign of the ignition timing gradual variation amount ΔTp is changed to set the tentative ignition timing Tptmp, and this is used as the ignition timing Tp. In this way, it is possible to suppress the ignition timing Tp from changing in a direction different from the direction toward the ignition timing base values ​​Tbase1, Tbase2 after the switching.

[0082] In the hybrid vehicle 20 of the embodiment, when the rapid catalyst warm-up control for idle-on is switched to the rapid catalyst warm-up control for idle-off, or when the rapid catalyst warm-up control for idle-off is switched to the rapid catalyst warm-up control for idle-on, the ignition timing Tp is gradually changed toward the ignition timing base value Tbase1, Tbase2 after the first predetermined time or the second predetermined time has elapsed. This makes it possible to suppress a sudden change in the ignition timing Tp. Also, when the rapid catalyst warm-up control for idle-on is switched to the rapid catalyst warm-up control for idle-off, or when the rapid catalyst warm-up control for idle-off is switched to the rapid catalyst warm-up control for idle-on, the engine control that prioritizes exhaust reduction can be continued in the same manner as the ignition timing Tp, and without disrupting the optimal balance between the amount of exhaust gas from the engine and the energy supplied to the catalyst. The upper and lower limit guard values ​​Tlim are gradually changed toward the upper and lower limit guard values ​​Tlim1, Tlim2 after the switching. As a result, even though the ignition timing Tp gradually changes toward the switched ignition timing base values ​​Tbase1, Tbase2, it is possible to prevent the ignition timing Tp from suddenly changing due to the switched upper and lower limit guard values ​​Tlim1, Tlim2.

[0083] In the hybrid vehicle 20 of the embodiment, the engine 22 is operated at a predetermined rotation speed Nset in both the idle-on rapid catalyst warm-up control and the idle-off rapid catalyst warm-up control, but the rotation speed Ne of the engine 22 may be different in the idle-on rapid catalyst warm-up control and the idle-off rapid catalyst warm-up control. That is, the engine 22 may be operated at a first predetermined rotation speed Nset1 in the idle-on rapid catalyst warm-up control, and the engine 22 may be operated at a second predetermined rotation speed Nset2 different from the first predetermined rotation speed Nset1 in the idle-off rapid catalyst warm-up control.

[0084] In the hybrid vehicle 20 of the embodiment, the engine 22 used is one in which the in-cylinder injection valve 127 is arranged approximately in the center of the top of the combustion chamber 129, but it is also possible to use an engine in which the in-cylinder injection valve 127 is arranged on the side wall (side) of the combustion chamber 129.

[0085] In the hybrid vehicle 20 of the embodiment, the engine 22 is provided with the port injection valve 126 and the in-cylinder injection valve 127, but an engine that does not include the port injection valve and only includes the in-cylinder injection valve may be used.

[0086] In the hybrid vehicle 20 of the embodiment, the battery 50 is used as the power storage device, but any device capable of storing power may be used, such as a capacitor.

[0087] The hybrid vehicle 20 of the embodiment includes the engine ECU 24, the motor ECU 40, the battery ECU 52, and the HVECU 70, but at least two of these may be configured as a single electronic control unit.

[0088] In the embodiment, the present invention has been described as being applied to a hybrid vehicle 20 including an engine 22, motors MG1 and MG2, and a planetary gear 30. However, the hybrid vehicle may have any configuration as long as it includes an engine, a first motor capable of generating electricity that is mechanically connected to the output shaft of the engine, and a second motor that can input and output power for running.

[0089] The correspondence between the main elements of the embodiment and the main elements of the invention described in the section on Means for Solving the Problems will be described below. In the embodiment, the purification device 135 corresponds to the "purification device", the engine 22 corresponds to the "engine", the motor MG1 corresponds to the "first electric motor", the motor MG2 corresponds to the "second electric motor", the battery 50 corresponds to the "electricity storage device", and the engine ECU 24, the motor ECU 40, and the HVECU 70 correspond to the "control device".

[0090] 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.

[0091] 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]

[0092] The present invention can be used in the hybrid vehicle manufacturing industry and the like. [Explanation of symbols]

[0093] 20 hybrid vehicle, 22 engine, 23 crankshaft, 24 engine ECU, 30 planetary gear, 36 drive shaft, 38 differential gear, 39a, 39b drive wheels, 40 motor ECU, 41, 42 inverter, 50 battery, 52 battery ECU, 54 power line, 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, 139 variable valve timing mechanism, 140 crank position sensor, 142 water temperature sensor, 144 cam position sensor, 150 fuel supply device, 151 fuel tank, 151t fuel temperature sensor, 152 feed pump, 152a rotational speed sensor, 153 low pressure supply pipe, 153p fuel pressure sensor, 154 check valve, 155 relief pipe, 156 relief valve, 157 high pressure pump, 157a solenoid valve, 157b check valve, 157c plunger, 158 high pressure supply pipe, 158p Fuel pressure sensor, MG1,MG2 motor.

Claims

1. an engine having an in-cylinder injection valve and a purification device having a catalyst for purifying exhaust gas attached to an exhaust system; a first electric motor mechanically connected to an output shaft of the engine and capable of generating electricity; A second electric motor capable of inputting and outputting power for traveling; an electricity storage device capable of exchanging electric power with the first electric motor and the second electric motor; a control device that controls the engine, the first electric motor, and the second electric motor; A hybrid vehicle comprising: The control device includes: when the engine is in an idle-off state where an idle operation of the engine is not instructed, and when rapid catalyst warm-up is performed by operating the engine with fuel injection during a compression stroke or an expansion stroke and retarding the ignition timing to warm up the catalyst of the purification device, the engine and the first electric motor are controlled so that the engine is operated at a first predetermined rotation speed while outputting a predetermined torque, and the second electric motor is controlled so that a driving force based on a required driving force is output; when the rapid catalyst warm-up is performed during the idle-off state, a first feedback control using a proportional term and an integral term is performed on an air amount and / or an ignition timing of the engine using an estimated engine torque estimated based on an output torque of the first electric motor. A hybrid vehicle characterized by

2. A hybrid vehicle according to claim 1, the control device performs the first feedback control when the estimated engine torque falls below a reference torque that is smaller than the predetermined torque, so that the estimated engine torque becomes equal to or greater than the reference torque. Hybrid car.

3. A hybrid vehicle according to claim 1, When the control device executes the rapid catalyst warm-up during an idle-on state in which an idle operation of the engine is instructed, the control device controls the engine and the first electric motor so that the engine operates autonomously at a second predetermined rotation speed, controls the second electric motor so that a driving force based on a required driving force is output, and performs a second feedback control using a proportional term and an integral term on an air amount and / or an ignition timing of the engine by using the rotation speed of the engine. Hybrid car.

4. A hybrid vehicle according to claim 3, The control device includes: When the idle-off state is switched to the idle-on state while the rapid catalyst warm-up is being performed, an integral term in the first feedback control is attenuated, When the idle-on state is switched to the idle-off state while the rapid catalyst warm-up is being performed, an integral term in the second feedback control is attenuated. Hybrid car.

5. A hybrid vehicle according to claim 4, The control device attenuates the integral term of the feedback control for the air amount based on the intake air amount at that time, and attenuates the integral term of the feedback control for the ignition timing based on the intake air amount at that time. attenuating based on a predetermined mode for a number of states; Hybrid car.

6. A hybrid vehicle according to claim 1, the control device prohibits the first feedback control when the rotation speed of the engine is increased by the first electric motor. Hybrid car.

7. A hybrid vehicle according to claim 3, the control device, when switching from the idle-off state to the idle-on state and from the idle-on state to the idle-off state while the rapid catalyst warm-up is being performed, holds an integral term of a feedback control for an ignition timing for a predetermined period of time. Hybrid car.

8. A hybrid vehicle according to claim 3, When feedback control is switched in association with switching from the idle-off state to the idle-on state and from the idle-on state to the idle-off state during execution of the rapid catalyst warm-up, and the ignition timing is corrected in a direction different from a post-switching ignition timing base value, an integral term in the post-switching feedback control is modified so that the ignition timing is corrected in the direction of the ignition timing base value. Hybrid car.

9. A hybrid vehicle according to claim 3, When the feedback control is switched in association with switching from the idle-off state to the idle-on state and from the idle-on state to the idle-off state while the rapid catalyst warm-up is being performed, the control device gradually changes the ignition timing toward a base value of the ignition timing after the switching. Hybrid car.

10. A hybrid vehicle according to claim 9, When the control device switches the feedback control in association with switching from the idle-off state to the idle-on state and from the idle-on state to the idle-off state while the rapid catalyst warm-up is being performed, the control device gradually changes the upper and lower limit guard values ​​toward the upper and lower limit guard values ​​after the switching. Hybrid car.

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