Vehicle control system

Abstract

To suppress a feeling of strangeness from being given to an occupant.SOLUTION: A control device of a vehicle, which controls an engine, a first motor and a second motor, executes air-fuel ratio lean control by which an air-fuel ratio of the engine is leaned, when at least one of a first condition that fuel cut of the engine is permitted, a second condition that the fuel cut of the engine is prohibited and motoring of the engine by the first motor is not required and a third condition that fuel cut of the engine is prohibited and vehicle speed is above predetermined vehicle speed is satisfied, in a case where a temperature of a filter is above a predetermined temperature. This can suppress a feeling of strangeness from being given to an occupant.SELECTED DRAWING: Figure 3

Description

[Technical Field]

[0001] The present disclosure relates to a vehicle control device. [Background Art]

[0002] Conventionally, as this type of vehicle control device, one used in a vehicle including an engine having a filter for removing particulate matter attached to an exhaust system and an automatic transmission has been proposed (see, for example, Patent Document 1). In this device, fuel cut of the engine is performed when the engine is decelerating and a temperature correlation value of lubricating oil of the automatic transmission is higher than a determination value. Then, when the deposition amount of particulate matter in the filter exceeds a first deposition amount, the determination value is made smaller than that before the deposition amount exceeds the first deposition amount. This increases opportunities for fuel cut and increases opportunities for filter regeneration. [Prior Art Literature] [Patent Literature]

[0003] [Patent Document 1] Japanese Unexamined Patent Publication No. 2021-148097 [Summary of the Invention] [Problem to be Solved by the Invention]

[0004] By the way, in the above-described vehicle control device, when the temperature of the filter becomes equal to or higher than a predetermined temperature during regeneration of the filter, fuel cut is prohibited and fuel injection of the engine is performed. At this time, abnormal noise may occur depending on the operating state of the engine, which gives a sense of discomfort to an occupant.

[0005] A main object of the vehicle control device of the present disclosure is to suppress giving a sense of discomfort to an occupant. [Means for Solving the Problem]

[0006] The vehicle control device of the present disclosure employs the following means to achieve the above-mentioned main object.

[0007] The control device of the first vehicle in this disclosure is A vehicle control device for controlling the engine and the first and second motors, used in a vehicle comprising: an engine with a filter attached to the exhaust system to remove particulate matter; a first motor; a planetary gear with three rotating elements connected to the engine, the first motor, and a drive shaft connected to the axle; a second motor connected to the drive shaft; and a power storage device that exchanges power with the first and second motors, wherein the vehicle control device controls the engine and the first and second motors, When the temperature of the filter is above a predetermined temperature, if at least one of the following conditions is met, the air-fuel ratio lean control is performed to set the air-fuel ratio of the engine to lean: a first condition that allows fuel cut-off of the engine; a second condition that prohibits fuel cut-off of the engine and no motoring request for the engine has been made by the first motor; and a third condition that prohibits fuel cut-off of the engine and the vehicle speed is above a predetermined vehicle speed. This is the gist of it.

[0008] In the control device for the first vehicle of this disclosure, the motoring request may be made when the maximum permissible input power that may be input to the energy storage device is less than a predetermined power. In this case, the air-fuel ratio lean control may prohibit fuel cut-off of the engine when the temperature of the filter is above the predetermined temperature, and when the motoring request has been made and deceleration is in progress, control the first motor so that the engine speed becomes a predetermined speed that does not produce abnormal noise, and control the air-fuel ratio of the engine to be lean.

[0009] The control device of the second vehicle in this disclosure is A vehicle control device used in a vehicle comprising an engine with a filter for removing particulate matter attached to the exhaust system, and a motor capable of motorizing the engine, for controlling the engine and the motor, When the temperature of the filter is above a predetermined temperature, and air-fuel ratio lean control is performed to set the engine's air-fuel ratio to lean, the motor is controlled so that the engine's rotational speed becomes a predetermined rotational speed that does not produce abnormal noise. This is the gist of it.

[0010] In the second vehicle control device of this disclosure, the predetermined rotational speed may be the lower limit of a predetermined range of rotational speeds in which no abnormal noise is generated. [Brief explanation of the drawing]

[0011] [Figure 1] This is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with the control device of this embodiment. [Figure 2] This is a schematic diagram showing the general configuration of engine 22. [Figure 3] This flowchart shows an example of a high-temperature processing routine executed by HVECI70. [Modes for carrying out the invention]

[0012] Embodiments of this disclosure will be described with reference to the drawings. Figure 1 is a schematic diagram showing the configuration of a hybrid vehicle 20 equipped with the control device of this embodiment. Figure 2 is a schematic diagram showing the configuration of an engine 22. As shown in Figure 1, the hybrid vehicle 20 of this embodiment includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 24, a planetary gear 30, motors MG1 and MG2 (first and second motors), motor electronic control units (hereinafter referred to as "motor ECU") 40, inverters 41 and 42, a battery 50 as an energy storage device, and a hybrid electronic control unit (hereinafter referred to as HVECU) 70. Here, the control devices of the vehicle are the engine ECU 24, the motor ECU 40, and the HVECU 70.

[0013] The engine 22 is configured as a four-cylinder internal combustion engine that outputs power through four strokes: intake, compression, expansion (explosive combustion), and exhaust, using a fuel such as gasoline or diesel. As shown in Figure 2, the engine 22 has a port injection valve 126 that injects fuel into the intake port and an in-cylinder injection valve 127 that injects fuel into the cylinder. By having the port injection valve 126 and the in-cylinder injection valve 127, the engine 22 can be operated in one of three modes: port injection mode, in-cylinder injection mode, or shared injection mode. In port injection mode, air cleaned by the air cleaner 122 is drawn into the intake manifold 123 and passes through the throttle valve 124 and surge tank 125, while fuel is injected from the port injection valve 126 downstream of the surge tank 125 in the intake manifold 123 to mix the air and fuel. This air-fuel mixture is then drawn into the combustion chamber 129 via the intake valve 128 and exploded and burned by an electric spark from the spark plug 130, converting the reciprocating motion of the piston 132, which is pushed down by the energy within the cylinder bore 131, into the rotational motion of the crankshaft 23. In the in-cylinder injection mode, air is drawn into the combustion chamber 129, similar to the port injection mode, and fuel is injected from the in-cylinder injection valve 127 during the intake and compression strokes, exploding and burning 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 also from the in-cylinder injection valve 127 during the intake and compression strokes, exploding and burning 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. The exhaust gas discharged from the combustion chamber 129 through the exhaust valve 133 to the exhaust pipe 134 is then discharged to the outside air via the exhaust system purification device 135 and PM filter 136. The purification device 135 has a purification catalyst (three-way catalyst) 135a that purifies harmful components such as carbon monoxide (CO), hydrocarbons (HC), and nitrogen oxides (NOx) in the exhaust gas. The PM filter 136 is formed as a porous filter using ceramics or stainless steel, and captures particulate matter (PM) such as soot in the exhaust gas.Alternatively, instead of the PM filter 136, a four-way catalyst combining the purification function of a three-way catalyst with the collection function for particulate matter may be used.

[0014] Engine 22 is controlled by the engine ECU 24. Although not shown in the diagram, the engine ECU 24 is configured as a microprocessor centered around a CPU, and in addition to the CPU, it includes ROM for storing processing programs, RAM for temporarily storing data, flash memory for storing and retaining data, input / output ports, and communication ports.

[0015] The engine ECU 24 receives signals from various sensors necessary for controlling the operation of the engine 22 via input ports. Examples of signals input to the engine ECU 24 include the crank angle θcr from the crank position sensor 140, which detects the rotational position of the crankshaft 23 of the engine 22, and the coolant temperature Tw from the coolant temperature sensor 142, which detects the temperature of the coolant of the engine 22. Other examples include the cam angles θci and θco from the cam position sensor 144, which detects the rotational position of the intake camshaft that opens and closes the intake valve 128 and the rotational position of the exhaust camshaft that opens and closes the exhaust valve 133. Other examples include the throttle opening TH from the throttle valve position sensor 124a, which detects the position of the throttle valve 124; the intake air volume Qa from the airflow meter 123a, which is installed upstream of the throttle valve 124 in the intake manifold 123; the intake air temperature Ta from the temperature sensor 123t, which is installed upstream of the throttle valve 124 in the intake manifold 123; and the surge pressure Ps from the pressure sensor 125a, which is installed in the surge tank 125. Other examples include the front air-fuel ratio AF1 from the front air-fuel ratio sensor 137, which is installed upstream of the purification device 135 in the exhaust manifold 134; the rear air-fuel ratio AF2 from the rear air-fuel ratio sensor 138, which is installed downstream of the purification device 135 in the exhaust manifold 134; and the differential pressure ΔP from the differential pressure sensor 136a, which detects the differential pressure before and after the PM filter 136 (the differential pressure between the upstream and downstream sides).

[0016] The engine ECU 24 outputs various control signals for controlling the operation of the engine 22 via its output ports. Examples of signals output from the engine ECU 24 include control signals to the throttle valve 124, control signals to the port injection valve 126, control signals to the in-cylinder injection valve 127, and control signals to the spark plug 130.

[0017] The engine ECU 24 is connected to the HVECU 70 via a communication port. The engine ECU 24 calculates the rotational speed Ne of the engine 22 based on the crank angle θcr of the engine 22 from the crank position sensor 140. The engine ECU 24 also calculates the load factor (the ratio of the volume of air actually inhaled in one cycle to the stroke volume per cycle of the engine 22) KL based on the intake air volume Qa from the airflow meter 123a and the rotational speed Ne of the engine 22. Furthermore, the engine ECU 24 calculates the PM deposit amount Qpm as the amount of particulate matter deposited on the PM filter 136 based on the differential pressure ΔP from the differential pressure sensor 136a, and calculates the filter temperature Tf as the temperature of the PM filter 136 based on the rotational speed Ne of the engine 22 and the load factor KL.

[0018] As shown in Figure 1, the planetary gear 30 is configured as a single-pinion type planetary gear mechanism. The rotor of the motor MG1 is connected to the sun gear of the planetary gear 30. The drive shaft 36, which is connected to the drive wheels 39a and 39b via a differential gear 38, is connected to the ring gear of the planetary gear 30. The crankshaft 23 of the engine 22 is connected to the carrier of the planetary gear 30 via a damper 28.

[0019] 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. Inverters 41 and 42 are used to drive the motors MG1 and MG2, and are connected to a battery 50 via a power line 54. The motors MG1 and MG2 are rotationally driven by switching control of a plurality of switching elements (not shown) of the inverters 41 and 42 by a motor ECU 40.

[0020] Although not shown, the motor ECU 40 is configured as a microprocessor centered on a CPU, and in addition to the CPU, includes a ROM for storing processing programs, a RAM for temporarily storing data, a flash memory for storing and retaining data, input / output ports, and a communication port. Signals from various sensors necessary for driving and controlling the motors MG1 and MG2 are input to the motor ECU 40 via an input port. Examples of the signals input to the motor ECU 40 include rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 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 of the respective phases of the motors MG1 and MG2 from current sensors (not shown) that detect phase currents flowing through the respective phases of the motors MG1 and MG2. Switching control signals to the plurality of switching elements (not shown) of the inverters 41 and 42 are output from the motor ECU 40 via an output port. The motor ECU 40 is connected to an HVECU 70 via a communication port. The motor ECU 40 calculates electrical angles θe1 and θe2 and rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 based on the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotational position sensors.

[0021] The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and as described above, is connected to the inverters 41 and 42 via a power line 54. The battery 50 is managed by a battery electronic control unit (hereinafter referred to as "battery ECU") 52.

[0022] Although not shown, the battery ECU 52 is configured as a microprocessor centered on a CPU, and includes, in addition to the CPU, a ROM that stores processing programs, a RAM that temporarily stores data, a flash memory that stores and retains data, an input / output port, and a communication port. Signals from various sensors necessary for managing the battery 50 are input to the battery ECU 52 via the input port. Examples of the signals input to the battery ECU 52 include the voltage Vb of the battery 50 from a voltage sensor (not shown) attached between the terminals of the battery 50, the current Ib of the battery 50 from a current sensor (not shown) attached to the output terminal of the battery 50, and the 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 the state of charge SOC of the battery 50 based on the integrated value of the current Ib of the battery 50 from the current sensor. The state of charge SOC is the ratio of the capacity of power dischargeable from the battery 50 to the total capacity of the battery 50. The battery ECU 52 also sets an output limit Wout as the allowable maximum output power that may be output from the battery 50 and an input limit Win as the allowable maximum input power that may be input to the battery 50, based on the state of charge SOC and the temperature Tb of the battery 50. The output limit Wout and the input limit Win of the battery 50 are set with a certain margin so as not to degrade the battery 50.

[0023] Although not shown in the diagram, the HVECU70 is configured as a microprocessor centered around a CPU. In addition to the CPU, it includes ROM for storing processing programs, RAM for temporarily storing data, flash memory for storing and retaining data, input / output ports, and communication ports. Signals from various sensors are input to the HVECU70 via its input ports. Examples of signals input to the HVECU70 include the ignition signal from the ignition switch 80 and the shift position SP from the shift position sensor 82, which detects the operating position of the shift lever 81. Other examples include the accelerator opening Acc from the accelerator pedal position sensor 84, which detects the amount the accelerator pedal 83 is pressed, the brake pedal position BP from the brake pedal position sensor 86, which detects the amount the brake pedal 85 is pressed, and the vehicle speed V from the vehicle speed sensor 88. As mentioned above, the HVECU70 is connected to the engine ECU24, motor ECU40, and battery ECU52 via its communication ports.

[0024] In the hybrid vehicle 20 of this embodiment, the HVECU 70, engine ECU 24, and motor ECU 40 are coordinated to operate in a hybrid driving mode (HV driving mode) in which the engine 22 is running, and an electric driving mode (EV driving mode) in which the engine 22 is stopped. In these driving modes, the engine 22 and motors MG1 and MG2 are controlled so that the driving torque Td* required for the drive shaft 36, based on the accelerator opening Acc and vehicle speed V, is output to the drive shaft 36.

[0025] In the hybrid vehicle 20 of this embodiment, when the engine 22 is operating in idle mode, the motor MG1 outputs a pressing torque that presses the planetary gear 30 in one direction. This suppresses the generation of abnormal noises such as tooth noise of the planetary gear 30 caused by torque pulsation when the engine 22 is operating in idle mode.

[0026] Furthermore, in the hybrid vehicle 20 of this embodiment, the regeneration of the PM filter 136 is performed by supplying air (oxygen) to the PM filter 136 by cutting off the fuel supply of the engine 22, and burning the particulate matter accumulated on the PM filter 136.

[0027] In the hybrid vehicle 20 of this embodiment, when air (oxygen) is supplied to the PM filter 136 by cutting off the fuel supply of the engine 22, the temperature of the PM filter 136 rises due to the combustion of particulate matter. To prevent the PM filter 136 from reaching high temperatures due to this temperature rise, when a predetermined time tfc has elapsed since the start of the fuel cut-off of the engine 22, the fuel cut-off is prohibited and the engine 22 is operated with an output corresponding to the accelerator opening Acc. When the input limit Win is less than a predetermined power Winref, such as when the battery 50 is cold, it is determined that a motoring request for the engine 22 (hereinafter referred to as "predetermined motoring request") has been made to prevent the battery 50 from being charged with power exceeding the input limit Win, and the engine 22 and motors MG1 and MG2 are controlled so that the above-mentioned driving torque Td* is output to the drive shaft 36 while the engine 22 is motored by motor MG1 and power is consumed. When the engine 22 is motorized by the motor MG1, a torque that reduces the rotational speed is applied to the drive shaft 36 via the planetary gear 30, thus preventing insufficient braking force from acting on the drive shaft 36 during deceleration.

[0028] Next, the operation of the hybrid vehicle 20 of this embodiment, as configured in this way, will be described in particular, the operation when suppressing the PM filter 136 from reaching a high temperature. Figure 3 is a flowchart of an example of a high-temperature processing routine executed by HVECI 70. The high-temperature processing routine is repeatedly executed when the filter temperature Tf exceeds a predetermined temperature T1 during engine 22 operation, until the filter temperature Tf falls below a predetermined temperature T2, which is lower than the predetermined temperature T1. Here, the predetermined temperature T1 is a threshold for determining whether or not the PM filter 136 may reach a high temperature, and is set to a temperature lower than the maximum temperature Tfmax that the PM filter 136 is allowed to reach (for example, a temperature 10°C, 20°C, or 30°C lower than the maximum temperature Tfmax). The predetermined temperature T2 is a temperature lower than the predetermined temperature T1 (for example, a temperature 10°C, 20°C, or 30°C lower than the predetermined temperature T1).

[0029] When this routine is executed, the engine ECU24 performs the process of inputting the vehicle speed V (S100). The vehicle speed V is the value detected by the vehicle speed sensor 88.

[0030] Next, it is determined whether or not fuel cut is prohibited (S110). If fuel cut is not prohibited (when the first condition of allowing fuel cut is met), it is determined that no predetermined motoring request has been made, and the first air-fuel ratio lean control is executed (S140), and this routine is terminated. In the first air-fuel ratio lean control, the first lean command is transmitted to the engine ECU 24, and at the same time, the motor MG1 is set to motorize the engine 22 so that the rotational speed Ne of the engine 22 becomes a predetermined rotational speed N1, and the torque commands Tm1* and Tm2* for motors MG1 and MG2 are set so that the above-mentioned driving torque Td* is output to the drive shaft 36, and these commands are transmitted to the motor ECU 40. Upon receiving the first lean command, the engine ECU 24 controls the engine 22 so that the air-fuel ratio becomes a predetermined value AFl (lean) which is greater than the stoichiometric air-fuel ratio. Upon receiving the torque commands Tm1* and Tm2*, the motor ECU 40 drives motors MG1 and MG2 with the torque commands Tm1* and Tm2*. The predetermined rotational speed N1 is the rotational speed at which the engine 22 can be operated without misfiring when the air-fuel ratio is set to a predetermined value AFl1, and has been set in advance through experiments, analyses, and machine learning. The predetermined value AFl is the rotational speed at which the air-fuel ratio is set in advance through experiments, analyses, and machine learning as the air-fuel ratio when the first air-fuel ratio lean control is performed. By performing the first air-fuel ratio lean control in this way, the amount of air supplied to the PM filter 136 can be made less than when fuel cut is performed, and more than when the engine 22 is controlled so that the air-fuel ratio is the stoichiometric air-fuel ratio. This makes it possible to regenerate the PM filter 136 while suppressing the temperature rise of the PM filter 136. When a predetermined motoring request is made and the engine 22 is being motored by the motor MG1, it becomes difficult to output the above-mentioned pressing torque from the motor MG1. Since increasing the air-fuel ratio makes combustion in the engine 22 unstable, there is a high possibility that abnormal noise will occur if the first air-fuel ratio lean control is performed when a predetermined motoring request is made. In this embodiment, since the first air-fuel ratio lean control is performed when fuel cut is permitted, that is, when no predetermined motoring request is made, the generation of abnormal noises can be suppressed, and discomfort to the occupants can be minimized.

[0031] When fuel cut is prohibited in S110, it is then determined whether a predetermined motoring request has been made (S120). If a predetermined motoring request has not been made (when the second condition is met), the first air-fuel ratio lean control is executed (S140), and this routine is terminated. This allows for the regeneration of the PM filter 136 while suppressing the temperature rise of the PM filter 136. Furthermore, as mentioned above, executing the first air-fuel ratio lean control when a predetermined motoring request has been made is likely to generate abnormal noise. In this embodiment, since the first air-fuel ratio lean control is executed when a predetermined motoring request has not been made, that is, when the possibility of abnormal noise generation is low, the generation of abnormal noise can be suppressed, and discomfort to the occupants can be minimized.

[0032] When a predetermined motoring request is made in S120, the next step is to determine whether the vehicle speed V is equal to or greater than the predetermined vehicle speed Vref (S130). The predetermined vehicle speed Vref is a vehicle speed that has been predetermined through experiments, analysis, and machine learning, which is the speed at which occupants will have difficulty recognizing abnormal noises such as tooth noises from the planetary gear 30 due to the noise of driving. When the vehicle speed V is equal to or greater than the predetermined vehicle speed Vref (when the third condition is met), it is determined that occupants will have difficulty recognizing abnormal noises even when the engine 22 is motored by the motor MG1, and the first air-fuel ratio lean control is executed (S140), and this routine is terminated. As a result, even if abnormal noises occur, occupants will have difficulty recognizing them due to the noise of driving, thus preventing them from feeling uncomfortable.

[0033] In S130, when the vehicle speed V is less than a predetermined vehicle speed Vref, it is determined that the occupants are likely to recognize the abnormal noise and whether or not there is a request for deceleration (S150). If there is a request for deceleration, the second air-fuel ratio lean control is executed (S160) and this routine is terminated. In the second air-fuel ratio lean control, a second lean command is sent to the engine ECU 24, and at the same time, the motor MG1 is used to motorize the engine 22 so that the rotational speed Ne of the engine 22 becomes a predetermined rotational speed N2, and torque commands Tm1* and Tm2* for motors MG1 and MG2 are set and sent to the motor ECU 40 so that the above-mentioned driving torque Td* is output to the drive shaft 36. Upon receiving the second lean command, the engine ECU 24 controls the engine 22 so that the air-fuel ratio becomes a predetermined value AFl2, which is greater than a predetermined value AFl. Upon receiving the torque commands Tm1* and Tm2*, the motor ECU 40 drives motors MG1 and MG2 with the torque commands Tm1* and Tm2*. The predetermined rotational speed N2 is higher than the predetermined rotational speed N1 and is the lower limit (lower limit rotational speed) of a predetermined range that is set in advance as a rotational speed range in which abnormal noise is less likely to occur when the engine 22 is motored by the motor MG1. This lower limit is determined in advance through experiments, analysis, and machine learning. By setting the predetermined rotational speed N2 higher than the predetermined rotational speed N1, it is possible to suppress insufficient braking force acting on the drive shaft 36 during deceleration. Furthermore, by performing second air-fuel ratio lean control, the amount of air supplied to the PM filter 136 is made less than when fuel cut is performed and more than when the air-fuel ratio is set to the stoichiometric air-fuel ratio or the predetermined value AFl1. This allows for the regeneration of the PM filter 136 while suppressing the temperature rise of the PM filter 136. Moreover, when the engine 22 is motored to the predetermined rotational speed N2, the planetary gear 30 is pressed to one side compared to when the predetermined rotational speed is N1, resulting in a situation in which abnormal noise is less likely to occur. Since the second air-fuel ratio control is performed in a state where these abnormal noises are unlikely to occur, it is possible to suppress any discomfort felt by the occupants.

[0034] If there is no deceleration request in S150, the routine is terminated by executing stoichiometric air-fuel ratio control (S170). In stoichiometric air-fuel ratio control, a normal control command is sent to the engine ECU 24, and at the same time, the motor MG1 is set to motorize the engine 22 so that the rotational speed Ne of the engine 22 becomes a predetermined rotational speed N1, and torque commands Tm1* and Tm2* for motors MG1 and MG2 are set and sent to the motor ECU 40 so that the above-mentioned driving torque Td* is output to the drive shaft 36. Upon receiving the normal control command, the engine ECU 24 controls the engine 22 so that the air-fuel ratio becomes the stoichiometric air-fuel ratio. Upon receiving the torque commands Tm1* and Tm2*, the motor ECU 40 drives motors MG1 and MG2 with the torque commands Tm1* and Tm2*. Thus, when fuel cut-off is prohibited, a predetermined motoring requirement is met, the vehicle speed V is less than the predetermined vehicle speed Vref, and there is no deceleration requirement, the air-fuel ratio is not made lean, thus suppressing the generation of abnormal noises and preventing discomfort to the occupants.

[0035] According to the hybrid vehicle 20 equipped with the vehicle control device of this embodiment described above, when the filter temperature Tf of the PM filter 136 is above a predetermined temperature T1, when fuel cut-off for the engine 22 is permitted, when fuel cut-off for the engine 22 is prohibited and no motoring request for the engine 22 by the motor MG1 is made, and when fuel cut-off for the engine 22 is prohibited and the vehicle speed V is above a predetermined vehicle speed Vref, at least one of the third conditions is met, the first air-fuel ratio lean control is performed to make the air-fuel ratio of the engine 22 lean, thereby suppressing any discomfort to the occupants when air-fuel ratio lean control is performed.

[0036] Furthermore, since the predetermined motoring request is made when the input limit Win is less than the predetermined power Winref, it is possible to suppress insufficient braking force acting on the drive shaft 36.

[0037] Furthermore, the second air-fuel ratio lean control prohibits fuel cut-off of the engine 22 when the filter temperature Tf is above a predetermined temperature Tfref, and when a predetermined motoring request is made and deceleration is in progress, it controls the motor MG1 so that the rotational speed of the engine 22 becomes a predetermined rotational speed N2 which is set in advance as the rotational speed of the engine 22 that does not produce abnormal noise, and also controls the air-fuel ratio of the engine 22 to be lean, thereby suppressing discomfort to the occupants and suppressing insufficient braking force acting on the drive shaft 36.

[0038] In the above embodiment, when the vehicle speed V is less than a predetermined vehicle speed Vref in S130, if there is a request for deceleration, the second air-fuel ratio lean control is performed, and if there is no request for deceleration, the stoichiometric air-fuel ratio control is performed. However, when the vehicle speed V is less than a predetermined vehicle speed Vref, the first air-fuel ratio lean control may be performed if there is a request for deceleration, and the stoichiometric air-fuel ratio control may be performed if there is no request for deceleration. Also, when the vehicle speed V is less than a predetermined vehicle speed Vref, the stoichiometric air-fuel ratio control may be performed regardless of whether there is a request for deceleration.

[0039] In the above embodiment, first air-fuel ratio control is performed in S140, but since it is sufficient to control the engine 22 so that the air-fuel ratio becomes lean, for example, second air-fuel ratio control may also be performed.

[0040] In the embodiment described above, the predetermined motoring request in S120 is made when the input limit Win is less than the predetermined power Winref. However, the predetermined motoring request may be made based on other requirements.

[0041] In the above-described embodiment, when the filter temperature Tf is above a predetermined temperature Tfref, in S110 to S150, the first air-fuel ratio control, the second air-fuel ratio control, and the stoichiometric air-fuel ratio control are executed depending on whether fuel cut is prohibited, whether a predetermined motoring request is made, whether the vehicle speed V is above a predetermined vehicle speed Vref, and whether a deceleration request is made. However, in another embodiment, when the filter temperature Tf is above a predetermined temperature Tfref, the second air-fuel ratio lean control may be executed. In this case, the control in the other embodiment can be applied to any vehicle that has an engine and a motor capable of motorizing the engine.

[0042] Furthermore, 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 problem is merely an example to specifically explain the form in which the embodiment implements the invention described in the section on means for solving the problem, and does not limit the elements of the invention described in the section on means for solving the problem. In other words, the interpretation of the invention described in the section on means for solving the problem should be based on the description in that section, and the embodiment is merely one specific example of the invention described in the section on means for solving the problem.

[0043] While embodiments for implementing this disclosure have been described above, this disclosure is not limited in any way to these embodiments, and can of course be implemented in various forms without departing from the gist of this disclosure. [Industrial applicability]

[0044] This disclosure can be used in industries such as the manufacturing of vehicle control systems. [Explanation of Symbols]

[0045] 24 Engine electronic control unit (engine ECU), 40 Motor electronic control unit (motor ECU), 50 Battery electronic control unit (battery ECU), 70 Hybrid electronic control unit (HVECU).

Claims

1. A vehicle control device for controlling the engine and the first and second motors, used in a vehicle comprising: an engine with a filter attached to the exhaust system to remove particulate matter; a first motor; a planetary gear with three rotating elements connected to the engine, the first motor, and a drive shaft connected to the axle; a second motor connected to the drive shaft; and a power storage device that exchanges power with the first and second motors, wherein the vehicle control device controls the engine and the first and second motors, When the temperature of the filter is above a predetermined temperature, if at least one of the following conditions is met: a first condition that allows fuel cut-off for the engine, a second condition that prohibits fuel cut-off for the engine and no motoring request for the engine has been made by the first motor, and a third condition that prohibits fuel cut-off for the engine and the vehicle speed is above a predetermined vehicle speed, the first motor is controlled to set the engine speed to a first rotational speed and lean air-fuel ratio control is performed to set the engine's air-fuel ratio to lean. If all of the first, second, and third conditions are not met and deceleration is in progress, the first motor is controlled to set the engine speed to a second rotational speed, which is predetermined as an engine speed higher than the first rotational speed that does not produce abnormal noise, and the lean air-fuel ratio control is performed. Vehicle control system.

2. A vehicle control device according to claim 1, The motoring request is made when the maximum permissible input power that may be input to the energy storage device is less than a predetermined power. Vehicle control system.

3. A vehicle control device according to claim 1 or 2, The second rotational speed is the lower limit of a predetermined range of rotational speeds within which no abnormal noise occurs in the engine. Vehicle control system.

4. A vehicle control device according to claim 1 or 2, When the temperature of the filter is above a predetermined temperature, and all of the first, second, and third conditions are not met, and the vehicle is not decelerating, the first motor is controlled so that the engine speed becomes the first rotational speed, and stoichiometric air-fuel ratio control is performed to set the air-fuel ratio to the stoichiometric air-fuel ratio. Vehicle control system.

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