control device

Abstract

To mitigate decrease in engine output torque.SOLUTION: A control device is mounted on a vehicle together with an engine having a plurality of cylinders and a PM filter collecting particulate matter in exhaust from the engine. The control device performs partial cylinder fuel cut to suspend fuel supply to a portion of the plurality of cylinders of the engine and power increment to control the engine in a manner that increments demand power to be output from the engine and causes the remaining portion of the plurality of cylinders to output the demand power. The control device starts the partial cylinder fuel cut after a period equal to or longer than a response delay period, which is lag time for the engine to respond, since start of power increment control.SELECTED DRAWING: Figure 2

Description

[Technical Field]

[0001] The present invention relates to a control device. [Background technology]

[0002] Conventionally, one such control device has been proposed that is mounted on a vehicle together with the engine and performs partial cylinder fuel cut, stopping fuel supply to some of the engine's multiple cylinders (see, for example, Patent Document 1). [Prior art documents] [Patent documents]

[0003] [Patent Document 1] Japanese Patent Publication No. 2022-65266 Summary of the Invention [Problem to be solved by the invention]

[0004] In recent years, the control device described above controls 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 among the multiple cylinders that are not subjected to fuel cut. However, even if the required power is boosted in this way, engine power does not increase immediately due to engine response delays, so when partial cylinder fuel cut begins, the engine output torque drops, which can cause a shock.

[0005] The main object of the control device of the present invention is to suppress a drop in the output torque of the engine. [Means for solving the problem]

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

[0007] 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 collects 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 raises 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 gist of this is as follows.

[0008] In this control system, partial cylinder fuel cut is initiated when the time elapsed since the start of power boosting is equal to or exceeds the response delay time of the engine. This compensates for the decrease in engine torque due to partial cylinder fuel cut with the increase in engine torque due to power boosting, thereby suppressing a drop in engine torque. [Brief explanation of the drawings]

[0009] [Figure 1] 1 is a schematic diagram of a hybrid vehicle 20 equipped with a control device according to an embodiment of the present invention. [Figure 2] 10 is a flowchart showing an example of a setting routine executed by the HVECU 70. [Figure 3] 10 is a timing chart showing an example of time-dependent changes in power boost, partial cylinder FC, and engine torque. DETAILED DESCRIPTION OF THE INVENTION

[0010] Next, a mode for carrying out the present invention will be described using examples. [Example]

[0011] 1 is a schematic diagram of a hybrid vehicle 20 equipped with a control device of the embodiment. As shown in the figure, 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 (electricity storage device) 50, a transmission 60, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0012] The engine 22 is configured as an internal combustion engine that outputs power using fuel such as gasoline or diesel. An exhaust system of the engine 22 is equipped with a purification device 25 that purifies unburned fuel and nitrogen oxides in the exhaust of the engine 22, and a PM filter 26 that collects particulate matter (PM) such as soot in the exhaust. The operation of the engine 22 is controlled by an engine ECU 28.

[0013] 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 amount Qa of the engine 22 from the air flow meter, and the pressure difference ΔPf between the upstream and downstream sides of the PM filter 26 from the differential pressure sensor 26a. The engine ECU 28 outputs control signals to the throttle valve, fuel injection valves, spark plugs, display 29, etc. The engine ECU 28 calculates the rotation speed Ne of the engine 22 based on the crank angle θcr, and calculates 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 amount Qa and the rotation speed Ne. The PM accumulation amount (accumulation amount of particulate matter accumulated on the PM filter 26) Qpm is calculated based on the differential pressure ΔPf, and the filter temperature (temperature of the PM filter 26) Tf is calculated based on the rotation speed Ne and the load factor KL.

[0014] The planetary gear 30 is configured as a single-pinion planetary gear mechanism, with the rotor of the motor MG1 connected to the sun gear, the crankshaft 23 of the engine 22 connected to the carrier, and the ring gear connected to an intermediate shaft 35. The rotor of the motor MG2 is attached to the intermediate shaft 35.

[0015] The motors MG1 and MG2 are configured as, for example, synchronous generator motors, and are rotationally driven by the HVECU 70 controlling the switching of a plurality of switching elements of the inverters 41 and 42.

[0016] 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.

[0017] The transmission 60 is configured as a stepped transmission with, for example, four, five, or six speeds. The input shaft of the transmission 60 is connected to an intermediate shaft 35, and the output shaft is connected to a drive shaft 36 that is coupled to drive wheels (wheels) 39a, 39b via a differential gear 38. The transmission 60 is controlled by an HVECU 70.

[0018] 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, the HVECU 70 receives inputs such as 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 inputs such as a start signal from a start switch 80, a shift position (shift lever operating position) SP from a shift position sensor 82, an accelerator opening (accelerator pedal depression amount) Acc from an accelerator pedal position sensor 84, a brake pedal position (brake pedal depression amount) BP from a brake pedal position sensor 86, and a vehicle speed V from a vehicle speed sensor 87. It outputs control signals to the inverters 41 and 42, the transmission 60, and the like. The HVECU 70 calculates the rotational speeds Nm1 and Nm2 of the motors MG1 and MG2 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 storage rate SOC of the battery 50 is calculated based on the integrated value of the current Ib, and the input / output limits (allowable input / output power) Win, Wout of the battery 50 are calculated based on the storage rate SOC and the temperature Tb.

[0019] In the hybrid vehicle 20, the engine 22, motors MG1, MG2, and transmission 60 are controlled by cooperative control between the engine ECU 28 and the HVECU 70 so that the hybrid vehicle 20 travels in an electric driving mode (EV driving mode) in which the engine 22 is stopped, or in 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, MG2 are controlled so that a required torque Ti* of the intermediate shaft 35 is output to the intermediate shaft 35 with the engine 22 running or stopped. The required torque Ti* is obtained by dividing the required torque Td* of the drive shaft 36 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.

[0020] When the start switch 80 is turned on and the system starts up (ready on), the HVECU 70 displays a switch SW on a touch panel (not shown) near the driver's seat for selecting whether or not to regenerate the PM filter 26 during load operation of the engine 22. When the user turns on the switch SW (presses the switch SW displayed on the display 29), the engine 22 is operated in regeneration mode while traveling in HV traveling mode until the system is stopped (ready off).

[0021] When the partial cylinder FC is turned on in a setting routine described later, the engine ECU 28 executes a partial cylinder fuel cut (partial cylinder FC) that stops fuel supply to some of the 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, thereby effectively burning particulate matter accumulated in the PM filter 26 and regenerating the PM filter 26.

[0022] When power boost is turned on in a setting routine described later, the HVECU 70 executes power boost to increase the required power Pe* compared to 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 a decrease in output torque of the engine 22 due to the start of partial cylinder operation FC. In this embodiment, when power boost is on, the HVECU 70 raises the required power Pe* by an amount of boost ΔPe relative to provisional required power Ptmp. In this embodiment, the amount of boost ΔPe is calculated by dividing 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.

[0023] Next, the operation of the 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, will be described. 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 (for example, 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.

[0024] When this routine is executed, the HVECU 70 determines whether the power boost is on (step S100). If the power boost is off, the HVECU 70 turns on the power boost (step S110). In this case, the HVECU 70 executes the power boost. The HVECU 70 turns off the power boost when the engine 22 is no longer operating under load (when the engine enters no-load operation or is stopped) or when the PM accumulation amount Qpm becomes less than a predetermined amount Qpmref.

[0025] Next, it is determined whether the elapsed time tpest since the power boost is turned on is equal to or greater than a predetermined time tref (step S120). The predetermined time tref is the time from when the 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 which the response of the engine 22 is delayed. This is based on the fact that even if the 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.

[0026] If the elapsed time tpest is less than the predetermined time tref in step S120, the partial cylinders FC are turned off (step S130), and this routine ends. In this case, the partial cylinders 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 cylinders FC are turned on (step S140), and this routine ends. In this case, the partial cylinders FC are executed.

[0027] Through this process, 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, the 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. FIG. 3 is a timing chart showing an example of time changes in power boost, partial cylinder FC, and output torque (engine torque) of the engine 22. In the comparative example, the power boost and partial cylinder FC (dashed line) are turned on at the same time (time t1). When the power boost and partial cylinder FC are turned on at the same time, the increase in engine torque (dashed line in the comparative example) due to the power boost begins after the predetermined time tref has elapsed due to a response delay of the engine 22, but a drop in engine torque (dashed line) due to the partial cylinder FC occurs immediately. Therefore, if 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 the embodiment, partial cylinder FC is turned on when the predetermined time tref has elapsed (time t2) after power boost is turned on. As a result, the increase in engine torque (dashed line in the embodiment) due to power boost compensates for the decrease in engine torque (chain line in the embodiment) due to partial cylinder FC, thereby suppressing the drop in engine torque (solid line in the embodiment).

[0028] According to the hybrid vehicle 20 equipped with the control device of the embodiment described above, the drop in engine torque (output torque of the engine 22) can be suppressed by starting partial cylinder FC when a predetermined time tref or more has elapsed since the start of power increase.

[0029] In a hybrid vehicle 20 equipped with the control device of the embodiment, the predetermined time tref is set as a time from when power boosting is turned on in the engine 22 until the power (torque) from the engine 22 actually starts to increase, and the partial cylinder FC is turned on to start the partial cylinder FC when the elapsed time tpest is equal to or longer 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 the partial cylinder FC may be turned on to start the partial cylinder FC when the estimated value Teest rises. 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.

[0030]

number

[0031] In the hybrid vehicle 20 equipped with the control device of the embodiment, the engine ECU 28 and the HVECU 70 may be integrated into one unit.

[0032] Although the control device of the embodiment is applied to the hybrid vehicle 20, it may also be applied to a gasoline engine vehicle that runs on power from the engine without having a motor as a power source for running.

[0033] 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 will be described below. In the embodiment, the engine ECU 28 and the HVECU 70 correspond to the "control device."

[0034] 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 carried out in various forms within the scope that does not deviate from the gist of the present invention. [Industrial Applicability]

[0035] The present invention can be used in the control device manufacturing industry and the like. [Explanation of symbols]

[0036] 20 Hybrid vehicles, 22 Engines, 28 Engine ECUs, 30 Planetary gears, 50 Batteries, 60 Transmissions, 70 HVECUs, MG1 and MG2 motors.

Claims

[Claim 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. [Equation 1] (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.)

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