JP7775801B2 - control device - Google Patents

Description

The present invention relates to a control device.

Conventionally, one such control device proposed is one that is mounted on a vehicle together with the engine and performs partial cylinder fuel cut, which stops fuel supply to some of the engine's multiple cylinders (see, for example, Patent Document 1).

Japanese Patent Application Laid-Open No. 2022-65266

In recent years, the above-mentioned control devices have controlled the engine so that when partial cylinder fuel cut is performed, the power required for driving plus the boosted power is output from the cylinders that are not undergoing fuel cut. However, even when the required power is boosted in this way, engine response delays mean that engine power does not increase immediately, which can cause a drop in engine output torque when partial cylinder fuel cut begins, resulting in a shock.

The primary purpose of the control device of the present invention is to suppress a drop in engine output torque.

The control device of the present invention employs the following measures to achieve the above-mentioned primary objective.

The control device of the present invention comprises:
A control device is mounted on a vehicle together with a multiple cylinder engine and a PM filter that captures particulate matter in exhaust gas from the engine, and performs a partial cylinder fuel cut that stops fuel supply to some of the multiple cylinders of the engine, and a power boost that boosts a required power to be output from the engine and controls the engine so that the required power is output from all cylinders of the multiple cylinders excluding the some cylinders,
The partial cylinder fuel cut is initiated when the time elapsed since the start of the power increase is equal to or exceeds a response delay time during which the response of the engine is delayed.

The control device of the present invention initiates partial cylinder fuel cut when the elapsed time since the start of power boosting is equal to or exceeds the response delay time during which the engine's response is delayed. This compensates for the decrease in torque output from the engine due to partial cylinder fuel cut with the increase in torque output from the engine due to power boosting, thereby suppressing the drop in torque output from the engine.

1 is a schematic diagram of a hybrid vehicle 20 equipped with a control device according to an embodiment of the present invention; 4 is a flowchart showing an example of a setting routine executed by an HVECU 70. 10 is a timing chart showing an example of time-dependent changes in power boost, partial cylinder FC, and engine torque;

Next, we will explain how to implement the present invention using examples.

Figure 1 is a schematic diagram of a hybrid vehicle 20 equipped with a control device according to an embodiment of the present invention. As shown, the hybrid vehicle 20 includes an engine 22, an engine electronic control unit (hereinafter referred to as "engine ECU") 28, a planetary gear 30, motors MG1 and MG2, inverters 41 and 42, a battery (electrical storage device) 50, a transmission 60, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

Engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel. The exhaust system of engine 22 is equipped with a purification device 25 that purifies unburned fuel and nitrogen oxides from the engine's 22 exhaust, and a PM filter 26 that captures particulate matter (PM) such as soot from the exhaust. The operation of engine 22 is controlled by engine ECU 28.

The engine ECU 28 has a microcomputer that receives signals from various sensors, outputs various control signals, performs various calculations, and communicates with the HVECU 70. For example, the engine ECU 28 receives inputs such as the crank angle θcr of the crankshaft 23 of the engine 22 from the crank position sensor 23a, the intake air volume Qa of the engine 22 from the air flow meter, and the differential pressure ΔPf between the upstream and downstream sides of the PM filter 26 from the differential pressure sensor 26a. It outputs control signals to the throttle valve, fuel injection valves, spark plugs, display 29, and the like. The engine ECU 28 calculates the engine speed Ne based on the crank angle θcr, and the load factor KL of the engine 22 (the ratio of the volume of air actually taken in per cycle to the stroke volume per cycle of the engine 22) based on the intake air volume Qa and the engine speed Ne. The PM accumulation amount Qpm (the amount of particulate matter accumulated in the PM filter 26) is calculated based on the differential pressure ΔPf, and the filter temperature Tf (the temperature of the PM filter 26) is calculated based on the rotation speed Ne and the load factor KL.

The planetary gear 30 is configured as a single-pinion planetary gear mechanism, with the rotor of motor MG1 connected to the sun gear, the crankshaft 23 of engine 22 connected to the carrier, and the ring gear connected to intermediate shaft 35. The rotor of motor MG2 is attached to intermediate shaft 35.

Motors MG1 and MG2 are configured, for example, as synchronous generator motors, and are driven to rotate by the HVECU 70 controlling the switching of multiple switching elements of inverters 41 and 42.

The battery 50 is configured as, for example, a lithium-ion secondary battery or a nickel-metal hydride secondary battery, and is connected to the power line 54 together with the inverters 41 and 42. The battery 50 is managed by the HVECU 70.

The transmission 60 is configured as a stepped transmission, such as a four-speed, five-speed, or six-speed transmission. The input shaft of the transmission 60 is connected to the intermediate shaft 35, and the output shaft is connected to the drive shaft 36, which is connected to the drive wheels 39a, 39b via a differential gear 38. The transmission 60 is controlled by the HVECU 70.

The HVECU 70 has a microcomputer that receives signals from various sensors, outputs various control signals, performs various calculations, and communicates with the engine ECU 28. For example, it receives the rotational positions θm1 and θm2 of the rotors of the motors MG1 and MG2 from the rotational position sensors 43 and 44, and the voltage Vb, current Ib, and temperature Tb of the battery 50 from the voltage sensor 51a, current sensor 51b, and temperature sensor 51c. It also receives the start signal from the start switch 80, the shift position (shift lever operating position) SP from the shift position sensor 82, the accelerator opening (accelerator pedal depression amount) Acc from the accelerator pedal position sensor 84, the brake pedal position (brake pedal depression amount) BP from the brake pedal position sensor 86, and the vehicle speed V from the vehicle speed sensor 87. It outputs control signals to the inverters 41 and 42, the transmission 60, and the like. The rotation speeds Nm1 and Nm2 of the motors MG1 and MG2 are calculated based on the rotational positions θm1 and θm2. The power Pb of the battery 50 is calculated as the product of the voltage Vb and the current Ib, the battery 50 power storage rate SOC is calculated based on the integrated value of the current Ib, and the input/output limits (allowable input/output power) Win and Wout of the battery 50 are calculated based on the power storage rate SOC and the temperature Tb.

In the hybrid vehicle 20, the engine ECU 28 and the HV ECU 70 cooperatively control the engine 22, motors MG1 and MG2, and transmission 60 to travel in either an electric driving mode (EV driving mode) in which the engine 22 is stopped, or a hybrid driving mode (HV driving mode) in which the engine 22 is running. In the HV driving mode, the engine 22 is controlled to output a required power Pe* based on the accelerator pedal position Acc and the vehicle speed V. The transmission 60 is controlled so that the gear position Gs becomes a target gear position Gs* based on the accelerator pedal position Acc and the vehicle speed V. The engine 22 and motors MG1 and MG2 are controlled so that the required torque Ti* of the intermediate shaft 35 is output to the intermediate shaft 35, with the engine 22 either stopped or running. The required torque Ti* is obtained by dividing the required torque Td* of the drive shaft 36, which is based on the accelerator opening Acc and the vehicle speed V, by the rotation speed ratio Gt corresponding to the gear position Gs of the transmission 60.

When the start switch 80 is turned on and the system is started (ready on), the HVECU 70 displays a switch SW on a touch panel (not shown) near the driver's seat to select whether or not to regenerate the PM filter 26 while the engine 22 is operating under load. When the user turns on the switch SW (presses the switch SW displayed on the display 29), the engine 22 operates in regeneration mode while driving in HV driving mode until the system is stopped (ready off).

When partial cylinder FC is turned on in the setting routine described below, the engine ECU 28 performs partial cylinder fuel cut (partial cylinder FC), which stops fuel supply to some of the multiple cylinders and supplies fuel to the remaining cylinders. This allows more oxygen to be introduced into the PM filter 26 from the cylinders to which fuel supply has been stopped, effectively burning particulate matter accumulated in the PM filter 26 and regenerating the PM filter 26.

When power boost is turned on in the setting routine described below, the HVECU 70 executes power boost to increase the required power Pe* compared to the provisional required power Petmp, which is the required power Pe* set at the same accelerator opening Acc and vehicle speed V when power boost is off. This is to prepare for the start of partial cylinder FC and a decrease in the output torque of the engine 22. In this embodiment, when power boost is on, the HVECU 70 raises the required power Pe* by an increase amount ΔPe relative to the provisional required power Ptmp. In this embodiment, the increase amount ΔPe is calculated by dividing the provisional required power Ptmp by the total number of cylinders Nt of the engine 22 and multiplying the result by the number of cylinders Nfc to which fuel supply is stopped.

Next, we will explain the operation of a hybrid vehicle 20 equipped with the control device of this embodiment configured as described above, particularly the operation when setting the on/off of partial cylinder FC and power boost. Figure 2 is a flowchart showing an example of a setting routine executed by the HVECU 70. This routine is repeatedly executed every predetermined time ts (e.g., every few msec) when the PM accumulation amount Qpm is equal to or greater than a predetermined amount Qpmref during regeneration mode and load operation of the engine 22.

When this routine is executed, the HVECU 70 determines whether power boost is on (step S100). If power boost is off, it turns power boost on (step S110). In this case, the HVECU 70 executes power boost. The HVECU 70 also turns power boost off when the engine 22 is no longer operating under load (when it enters no-load operation or is stopped), or when the PM accumulation amount Qpm becomes less than the predetermined amount Qpmref.

Next, it is determined whether the elapsed time tpest since power boost was turned on is equal to or greater than a predetermined time tref (step S120). The predetermined time tref is the time from when power boost is turned on in the engine 22 until the power (torque) from the engine 22 actually starts to increase, i.e., a time that is predetermined as a response delay time for the engine 22. This is based on the fact that even if power boost is started in the engine 22, the power (torque) from the engine 22 does not increase immediately due to a response delay of the engine 22.

If the elapsed time tpest is less than the predetermined time tref in step S120, the partial cylinder FC is turned off (step S130) and the routine ends. In this case, partial cylinder FC is not executed, and fuel is supplied to all cylinders of the engine 22 to operate the engine 22. If the elapsed time tpest is equal to or greater than the predetermined time tref in step S120, the partial cylinder FC is turned on (step S140) and the routine ends. In this case, partial cylinder FC is executed.

Through this processing, when the PM accumulation amount Qpm is equal to or greater than the predetermined amount Qpmref during regeneration mode and load operation of the engine 22, partial cylinder FC is turned on when the elapsed time tpest since power boost was turned on is equal to or greater than the predetermined time tref, i.e., when the predetermined time tref has elapsed since power boost was turned on. Figure 3 is a timing chart showing an example of the time changes in power boost, partial cylinder FC, and engine 22 output torque (engine torque). In the comparative example, power boost and partial cylinder FC (dashed line) are turned on at the same time (time t1). When power boost and partial cylinder FC are turned on at the same time, the increase in engine torque due to power boost (dashed line in the comparative example) begins after the predetermined time tref has elapsed due to a response delay of the engine 22, but a drop in engine torque due to partial cylinder FC (dash-dotted line) immediately occurs. Therefore, when power boost and partial cylinder FC are turned on at the same time, engine torque (solid line in the comparative example) drops for a predetermined time tref (time t1 to t2). In this embodiment, partial cylinder FC is turned on when the predetermined time tref has elapsed (time t2) after power boost is turned on. This compensates for the decrease in engine torque (dashed line in the embodiment) due to partial cylinder FC by the increase in engine torque (dashed line in the embodiment), thereby suppressing the drop in engine torque (solid line in the embodiment).

With the hybrid vehicle 20 equipped with the control device of the embodiment described above, partial cylinder FC can be initiated when a predetermined time tref or more has elapsed since power boosting began, thereby suppressing a drop in engine torque (output torque of the engine 22).

In a hybrid vehicle 20 equipped with the control device of the embodiment, the predetermined time tref is set as the time from when power boost is turned on in the engine 22 until the power (torque) from the engine 22 actually starts to increase, and partial cylinder FC is turned on when the elapsed time tpest is equal to or greater than the predetermined time tref. However, an estimated value Teest of the torque output from the engine 22 may be calculated using the following equation (1), and partial cylinder FC may be turned on when the estimated value Teest rises to start partial cylinder FC. In equation (1), "ρ" is the gear ratio of the planetary gear 30, "Tg" is the torque output from the motor MG1, "Ie" is the moment of inertia of the engine 22, "Ig" is the moment of inertia of the motor MG1, "ωg" is the rotational speed of the motor MG1, and "ωe" is the rotational speed of the engine 22.

In a hybrid vehicle 20 equipped with the control device of the embodiment, the engine ECU 28 and the HV ECU 70 may be configured as an integrated unit.

The control device of the embodiment is applied to a hybrid vehicle 20, but it may also be applied to a gasoline engine vehicle that runs on engine power without having a motor as a power source for running.

The following explains the correspondence between the main elements of the embodiment and the main elements of the invention described in the "Means for Solving the Problem" section. In the embodiment, the engine ECU 28 and HVECU 70 correspond to the "control device."

The above describes the form for carrying out the present invention using examples, but the present invention is not limited to these examples in any way, and it goes without saying that the present invention can be embodied in various forms without departing from the spirit of the present invention.

This invention can be used in industries such as control device manufacturing.

20 Hybrid vehicle, 22 Engine, 28 Engine ECU, 30 Planetary gear, 50 Battery, 60 Transmission, 70 HV ECU, MG1, MG2 Motor.

Claims (1)

a control device mounted on a vehicle together with a multiple cylinder engine, a PM filter that collects particulate matter in exhaust from the engine, a first motor, a second motor, a planetary gear connected to the first motor, a crankshaft of the engine, and an intermediate shaft to which the second motor is connected, and a transmission having an input shaft connected to the intermediate shaft and an output shaft connected to a drive shaft connected to drive wheels , the control device performing a partial cylinder fuel cut that stops fuel supply to some of the multiple cylinders of the engine, and a power boost that boosts a required power to be output from the engine and controls the engine so that the required power is output from all cylinders of the multiple cylinders excluding the some cylinders,
When the time elapsed since the start of the power increase is equal to or longer than a response delay time during which the response of the engine is delayed, the partial cylinder fuel cut is started ,
The response delay time is expressed by the following equation (1):
Control device.
(where ρ is the gear ratio of the planetary gear, Tg is the torque output from the first motor, Ie is the moment of inertia of the engine, Ig is the moment of inertia of the first motor, ωg is the rotational speed of the first motor, and ωe is the rotational speed of the engine.)