Control device

Abstract

To suppress an abrupt change in a rotation speed of an engine.SOLUTION: A control device executes catalyst warming-up control to control an engine and a rotation speed adjustment device so that a rotation speed of the engine becomes a warming-up rotation speed capable of effectively warming up a catalyst when a temperature of the catalyst is less than a predetermined temperature. When an accumulation amount on a PM filter is equal to or more than a predetermined amount, the control device controls the engine and the rotation speed adjustment device so that the engine is operated at the rotation speed equal to or more than a lower limit rotation speed while executing a partial cylinder fuel cut in which fuel supply to at least one of a plurality of cylinders of an engine is suspended and a lower limit rotation speed increase process to increase a lower rotation speed of the engine from a misfire prevention rotation speed to a vibration prevention rotation speed through the partial cylinder fuel cut. The control device suppresses at least execution of the lower limit rotation speed increase process while the catalyst warming-up control is in execution.SELECTED DRAWING: Figure 2

Description

Technical Field

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

Background Art

[0002] Conventionally, as this type of control device, an engine device including an engine having a plurality of cylinders, a PM filter that collects particulate matter in the exhaust from the engine, and a rotational speed adjustment device that adjusts the rotational speed of the engine has been proposed. (For example, see Patent Document 1). In this device, when performing partial cylinder fuel cut (partial cylinder FC) control that stops fuel supply to at least one cylinder among a plurality of cylinders for regeneration of the PM filter, the engine speed is increased compared to when the partial cylinder FC control is not being executed. This suppresses deterioration of drivability when the partial cylinder FC control is being executed.

Prior Art Documents

Patent Documents

[0003]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0004] In recent years, in the above-described device, a device further including an exhaust gas purification device having a catalyst for purifying exhaust from the engine has been proposed. In this device, when the catalyst is below a predetermined temperature, in order to suppress deterioration of the exhaust gas, catalyst warm-up control is executed to control the engine and the rotational speed adjustment device so that the engine is operated at a warm-up rotational speed at which the catalyst can be efficiently warmed up. In this device, when shifting from catalyst warm-up control to partial cylinder fuel cut, the rotational speed of the engine may change suddenly.

[0005] The main object of the control device of the present disclosure is to suppress a sudden change in the rotational speed of the engine.

Means for Solving the Problem

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

[0007] The control device of the present disclosure is mounted on an engine device including an engine having a plurality of cylinders, an exhaust purification device having a catalyst for purifying exhaust from the engine, a PM filter for collecting particulate matter in the exhaust from the engine, and a rotational speed adjustment device for adjusting the rotational speed of the engine, when the catalyst is below a predetermined temperature, catalyst warm-up control is executed to control the engine and the rotational speed adjustment device so that the rotational speed of the engine becomes a warm-up rotational speed at which the catalyst can be efficiently warmed up, when the deposition amount of the PM filter is equal to or more than a predetermined amount, a partial cylinder fuel cut for stopping the fuel supply to at least one of the plurality of cylinders of the engine and a lower limit rotational speed increase for raising the lower limit rotational speed of the engine from a misfire suppression rotational speed to a vibration suppression rotational speed for suppressing vibration caused by the partial cylinder fuel cut are executed, and the engine and the rotational speed adjustment device are controlled so that the engine is operated at a rotational speed equal to or higher than the lower limit rotational speed a control device, when the catalyst warm-up control is being executed, at least the execution of the lower limit rotational speed increase is restricted This is the gist.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Mode for Carrying Out the Invention

[0009] Next, embodiments for implementing the present disclosure will be described with reference to the drawings. FIG. 1 is a schematic configuration diagram of a hybrid vehicle 20 equipped with the 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 (power storage device) 50, a transmission 60, and a hybrid electronic control unit (hereinafter referred to as "HVECU") 70.

[0010] The engine 22 is configured as an internal combustion engine that outputs power using fuels such as gasoline and diesel oil. In the exhaust system of the engine 22, there are attached a purification device (exhaust 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 purification device 25 is provided with a catalyst that purifies exhaust containing carbon monoxide (CO) and hydrocarbons (HC). The engine 22 is under operation control by the engine ECU 28. The engine ECU 28 has a microcomputer, inputs signals from various sensors, outputs various control signals, performs various calculations, and communicates with the HVECU 70. For example, it inputs 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, the differential pressure ΔPf between the front and rear (upstream side and downstream side) of the PM filter 26 from the differential pressure sensor 26a, etc. It outputs control signals to the throttle valve, fuel injection valve, ignition plug, etc. It calculates the rotational 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 inhaled in one cycle to the stroke volume per cycle of the engine 22) based on the intake air amount Qa and the rotational speed Ne. It calculates the PM deposition amount (the deposition amount of particulate matter deposited on the PM filter 26) Qpm based on the differential pressure ΔPf, and calculates the filter temperature (the temperature of the PM filter 26) Tf based on the rotational speed Ne and the load factor KL.

[0011] 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, the crankshaft 23 of the engine 22 is connected to the carrier, and the intermediate shaft 35 is connected to the ring gear. The rotor of the motor MG2 is attached to the intermediate shaft 35. The motors MG1 and MG2 are configured as, for example, synchronous generator motors, and are rotationally driven by switching control of a plurality of switching elements of the inverters 41 and 42 by the HVECU 70. 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. This battery 50 is managed by the HVECU 52. The transmission 60 is configured as a stepped transmission such as a 4-speed transmission, a 5-speed transmission, or a 6-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 that is connected to the drive wheels 39a and 39b via the differential gear 38. The transmission 60 is controlled by the HVECU 70.

[0012] The HVECU 70 has a microcomputer, inputs signals from various sensors, outputs various control signals, performs various calculations, and communicates with the engine ECU 28. For example, it inputs the rotational positions θm1, θm2 of the rotors of the motors MG1, MG2 from the rotational position sensors 43, 44, 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 inputs the start signal from the start switch 80, the shift position (operation position of the shift lever) SP from the shift position sensor 82, the accelerator opening (depression amount of the accelerator pedal) Acc from the accelerator pedal position sensor 84, the brake pedal position (depression amount of the brake pedal) 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, 42, the transmission 60, etc. It calculates the rotational speeds Nm1, Nm2 of the motors MG1, MG2 based on the rotational positions θm1, θm2. It calculates the power Pb of the battery 50 as the product of the voltage Vb and the current Ib, calculates the state of charge SOC of the battery 50 based on the integrated value of the current Ib, and calculates the input / output limits (allowable input / output power) Win, Wout of the battery 50 based on the state of charge SOC and the temperature Tb.

[0013] In the hybrid vehicle 20, the engine 22, motors MG1 and MG2, and the transmission 60 are controlled so as to travel in an electric driving mode (EV driving mode) that travels with the rotation of the engine 22 stopped or in a hybrid driving mode (HV driving mode) that travels with the rotation of the engine 22, by cooperative control between the engine ECU 28 and the HV ECU 70. The transmission 60 is controlled so that the gear stage Gs becomes the target gear stage Gs* based on the accelerator opening Acc and the vehicle speed V. The engine 22 and the motors MG1 and MG2 are basically controlled to operate at the higher one of the rotation speed at which the engine 22 operates efficiently and the lower limit rotation speed Nemin, while the required torque Ti* of the intermediate shaft 35 is output to the intermediate shaft 35. The lower limit rotation speed Nemin is basically the misfire suppression rotation speed Nnf determined in advance as the lower limit value of the rotation speed at which the engine 22 does not misfire. 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 stage Gs of the transmission 60.

[0014] When the temperature of the purification device 25 is lower than a predetermined temperature Tfbref which is the lower limit value of the temperature at which the catalyst is activated, the HV ECU 70 executes catalyst warm-up control to control the engine 22, the motor MG1, and the motor MG2 so that the required torque Ti* is output to the intermediate shaft 35 while operating the engine 22 at a warm-up rotation speed Nwu (for example, 1200 rpm, 1300 rpm, 1400 rpm, etc.) determined in advance as the rotation speed at which the catalyst is efficiently warmed up, regardless of the lower limit rotation speed Nemin. Then, when the temperature of the purification device 25 is equal to or higher than the predetermined temperature Tfbref, the catalyst warm-up control is stopped, and the engine 22, the motor MG1, and the motor MG2 are controlled so that the required torque Ti* is output to the intermediate shaft 35 while operating the engine 22 at the higher one of the rotation speed at which the engine 22 operates efficiently and the lower limit rotation speed Nemin.

[0015] When the start switch 80 is turned on and the system starts up (ready on), the HVECU 70 displays a switch SW on a display (not shown) which is a touch panel near the driver's seat for selecting whether to perform regeneration of the PM filter 26 during the load operation of the engine 22. When the user turns on the switch SW (presses the switch SW displayed on the display), the engine 22 is operated in the regeneration mode during driving in the HV driving mode until the system stops (ready off).

[0016] In the regeneration mode, when the PM accumulation amount Qpm is equal to or greater than a predetermined amount Qpmref during driving in the HV driving mode and during the load operation of the engine 22, a partial cylinder fuel cut (partial cylinder FC) that stops the fuel supply to at least any one of the plurality of cylinders is executed, and while performing a lower limit rotation speed increase that sets the lower limit rotation speed Nemin of the engine 22 to a vibration suppression rotation speed Nnb higher than the misfire suppression rotation speed Nnf, the engine 22 is operated at the higher of the rotation speed for efficiently operating the engine 22 and the lower limit rotation speed Nemin, and filter regeneration control for controlling the engine 22 and the motors MG1, MG2 so that the required torque Ti* is output to the intermediate shaft 35 is executed. The vibration suppression rotation speed Nnv is a rotation speed higher than the rotation speed of the engine 22 at which the vibration of the vehicle increases due to resonance caused by the pulsating torque of the engine 22 generated by the partial cylinder FC (for example, 2500 rpm, 2600 rpm, 2700 rpm, etc.), and is set higher than the misfire suppression rotation speed Nnf and the warm-up rotation speed Nwu. By such filter regeneration control, the vibration of the vehicle due to the pulsating torque of the engine 22 generated by the partial cylinder FC control is suppressed, and air (oxygen) is supplied to the PM filter 26 to burn the particulate matter deposited on the PM filter 26, and regeneration of the PM filter 26 is performed.

[0017] Next, the operation of the hybrid vehicle 20, particularly the operation in the regeneration mode, will be described. FIG. 2 is a flowchart showing an example of a processing routine executed by the HVECU 70. This routine is repeatedly executed every predetermined time (for example, every few msec) when the PM deposition amount Qpm is equal to or greater than a predetermined amount Qpmref during traveling in the HV driving mode and during the load operation of the engine 22, that is, when a regeneration request for the PM filter 26 is made during traveling in the HV driving mode and during the load operation of the engine 22.

[0018] When this routine is executed, the CPU of the HVECU 70 determines whether or not the regeneration mode is selected (step S100). When it is not the regeneration mode, this routine is terminated. When it is not the regeneration mode, basically, fuel is supplied to all of the plurality of cylinders, and the engine 22 is efficiently operated at a rotation speed equal to or higher than the lower limit rotation speed Nemin with the lower limit rotation speed Nemin as the misfire suppression rotation speed Nfb, while controlling the engine 22 and the motors MG1 and MG2 so that the required torque Ti* is output to the intermediate shaft 35.

[0019] When it is the regeneration mode in step S100, subsequently, it is determined whether or not the above-described catalyst warm-up control is being executed (step S110). When the catalyst warm-up control is not being executed, filter regeneration control, that is, partial cylinder FC and raising of the lower limit rotation speed are executed (step S120), and this routine is terminated. Thereby, the vibration of the vehicle due to the pulsating torque of the engine 22 generated by the partial cylinder FC is suppressed, and the PM filter 26 is regenerated.

[0020] When the catalyst warm-up control is being executed in step S110, the execution of the filter regeneration control is restricted (without executing the filter regeneration control), that is, the execution of the partial cylinder FC and the raising of the lower limit rotation speed are restricted (without executing the partial cylinder FC and the raising of the lower limit rotation speed) (step S130), and this routine is terminated. In this case, the partial cylinder FC and the raising of the lower limit rotation speed are not executed, and the catalyst warm-up control is continued.

[0021] FIG. 3 is a timing chart showing an example of the time variation of the state of switch SW, accelerator opening Acc, execution of catalyst warm-up control, execution of lower limit speed increase, lower limit speed Nemin of engine 22, and execution of partial cylinder FC when the PM deposition amount Qpm is equal to or greater than a predetermined amount Qpmref. In the embodiment, during the execution of the catalyst warm-up control, the lower limit speed Nemin is set to the misfire suppression speed Nnf, but the engine speed of engine 22 is set to the warm-up speed Nwu regardless of the lower limit speed Nemin. When the catalyst warm-up control stops (at time ts), the lower limit speed increase is executed, and when the lower limit speed Nemin rises from the misfire suppression speed Nnf to the vibration suppression speed Nnv at a predetermined rate and reaches the vibration suppression speed Nnv, the partial cylinder FC is started and the filter regeneration control is started. If the lower limit speed increase is executed during the catalyst warm-up control, when the catalyst warm-up control stops, the lower limit speed Nemin has already become the vibration suppression speed Nnv. In this embodiment, since the vibration suppression speed Nnv is higher than the warm-up speed Nwu, the engine speed of engine 22 suddenly changes from the warm-up speed Nwu to a speed equal to or higher than the vibration suppression speed Nnv. In this embodiment, during the execution of the catalyst warm-up control, the filter regeneration control, that is, the execution of the partial cylinder FC and the lower limit speed increase is restricted, the execution of the lower limit speed increase is started after the catalyst warm-up control stops, and then the execution of the partial cylinder FC is started. Thereby, when the catalyst warm-up control is stopped, since the lower limit speed Nemin is lower than the warm-up speed Nwu, a sudden change in the engine speed of engine 22 can be suppressed.

[0022] According to the hybrid vehicle 20 equipped with the control device of the embodiment described above, when the catalyst warm-up control is being executed, a sudden change in the engine speed of engine 22 can be suppressed by restricting at least the execution of the lower limit speed increase.

[0023] In the hybrid vehicle 20 of the above-described embodiment, the transmission 60 may not be provided. Further, the engine ECU 28 and the HV ECU 70 may be integrally configured.

[0024] In the above-described embodiment, the case where the control device of the present disclosure is applied to the hybrid vehicle 20 has been exemplified. However, the control device of the present disclosure may be applied to an engine device including an engine and a rotational speed adjustment device that adjusts the rotational speed of the engine.

[0025] The correspondence relationship between the main elements of the embodiment and the main elements of the invention described in the column of means for solving the problems will be described. In the embodiment, the HVECU 70 corresponds to the "control device".

[0026] The present disclosure is not limited to the above-described embodiment in any way, and it goes without saying that the present disclosure can be implemented in various forms without departing from the gist of the present disclosure.

Industrial Applicability

[0027] The present invention can be used in the manufacturing industry of control devices and the like.

Explanation of Reference Numerals

[0028] 20 Hybrid vehicle, 22 Engine, 28 Engine electronic control unit (Engine ECU), 30 Planetary gear, 50 Battery, 60 Transmission, 70 Hybrid electronic control unit (HVECU), MG1, MG2 Motors.

Claims

【Claim 1】 An engine device mounted on an engine device including a multi-cylinder engine, an exhaust gas purification device having a catalyst for purifying exhaust gas from the engine, a PM filter for collecting particulate matter in the exhaust gas from the engine, and a rotational speed adjusting device for adjusting the rotational speed of the engine, when the catalyst is below a predetermined temperature, catalyst warm-up control is executed to control the engine and the rotational speed adjusting device so that the rotational speed of the engine becomes a warm-up rotational speed at which the catalyst can be efficiently warmed up, when the deposition amount of the PM filter is equal to or more than a predetermined amount, a partial cylinder fuel cut for stopping the fuel supply to at least one cylinder among the plurality of cylinders of the engine, and a lower limit rotational speed increase for raising the lower limit rotational speed of the engine from the misfire suppression rotational speed to a vibration suppression rotational speed for suppressing vibration caused by the partial cylinder fuel cut are executed, and the engine and the rotational speed adjusting device are controlled so that the engine is operated at a rotational speed equal to or higher than the lower limit rotational speed A control device, when the catalyst warm-up control is being executed, at least the execution of the lower limit rotational speed increase is restricted Control device.

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