JP2022011532A - Control device for vehicle - Google Patents

Abstract

To provide a control device for a vehicle capable of ensuring a detection opportunity of an OBD and improving drivability during the OBD.SOLUTION: In a control device for a vehicle, the vehicle includes: an internal combustion engine that is a driving source of the vehicle; an electric motor that is a driving source of the vehicle and can generate electric power by using output from the internal combustion engine; and a transmission connected to the internal combustion engine and the electric motor. In the control device for the vehicle, the control device includes: a change amount acquisition section acquiring a change amount of output from the internal combustion engine when an abnormality determination of the internal combustion engine is made; a threshold value setting section setting a threshold value relative to the change amount of the output from the internal combustion engine in accordance with a change gear ratio of the transmission; and an output control section allowing a change of the output from the internal combustion engine when a request value is smaller than the threshold value, and setting the change amount of the output from the internal combustion engine to the threshold value when the request value is the threshold value or greater.SELECTED DRAWING: Figure 3

Description

The present invention relates to a vehicle control device.

In a vehicle, an abnormality determination (OBD: On Board Diagnosis) of an internal combustion engine may be performed. A load may be created for the OBD to keep the output of the internal combustion engine within a predetermined range (eg, steady state). OBD of an internal combustion engine is also performed in a hybrid vehicle using an internal combustion engine and an electric motor as drive sources (for example, Patent Document 1).

Japanese Unexamined Patent Publication No. 2012-006416

When performing an active operation to output a predetermined output of an internal combustion engine, the output of the internal combustion engine may vary. In a hybrid vehicle, the motor performs power running and charging to stabilize the output transmitted to the drive system and suppress the deterioration of drivability. However, if the output of the internal combustion engine cannot be accurately detected, it becomes difficult for the electric motor to operate according to the variation in the output of the internal combustion engine. As a result, sudden fluctuations in torque may occur and drivability may deteriorate. Therefore, it is an object of the present invention to secure an opportunity to detect OBD and to provide a vehicle control device capable of improving drivability during OBD.

The object is a vehicle control device, wherein the vehicle is an internal combustion engine that is a drive source of the vehicle, and an electric motor that is a drive source of the vehicle and can generate power by using the output of the internal combustion engine. And a transmission that is connected to the internal combustion engine and the electric motor, and the control device includes a change amount acquisition unit that acquires a change amount of the output of the internal combustion engine when executing an abnormality determination of the internal combustion engine. A threshold setting unit that sets a threshold value for a change amount of the output of the internal combustion engine according to the gear ratio of the transmission, and when the required value is less than the threshold value, the change of the output of the internal combustion engine is allowed. When the required value is equal to or greater than the threshold value, it can be achieved by a vehicle control device including an output control unit that sets the amount of change in the output of the internal combustion engine to the threshold value.

It is possible to provide a vehicle control device that can secure an opportunity to detect OBD and improve drivability during OBD.

FIG. 1 is a schematic diagram illustrating a hybrid vehicle. FIG. 2A is a time chart at the time of OBD implementation. FIG. 2B is a diagram showing a threshold value of the amount of change in the output of the internal combustion engine. FIG. 3 is a flowchart in the embodiment.

Hereinafter, the vehicle control device of the present embodiment will be described with reference to the drawings. FIG. 1 is a schematic diagram illustrating the hybrid vehicle 100. The hybrid vehicle 100 includes an internal combustion engine 10, wheels 11, a motor generator (MG) 12, a transmission 14, a differential gear 16, a battery 20, an HV (hybrid) ECU (Electronic Control Unit) 40, an engine ECU 42, and a motor ECU 44. , A battery ECU 46 is provided.

The internal combustion engine 10 is, for example, a gasoline engine or a diesel engine, and burns fuel such as gasoline or light oil to generate power. The internal combustion engine 10 is connected to the MG 12. The clutch 13 is, for example, a hydraulic clutch, and is provided between the internal combustion engine 10 and the MG 12. The transmission 14 may be an automatic transmission that automatically switches a plurality of gear ratios, such as forward 6-speed and reverse 1-speed, or may be a continuously variable transmission (CVT). The internal combustion engine 10 and the MG 12 are connected to the transmission 14 and are connected to the differential gear 16 via the transmission 14. The differential gear 16 is connected to the wheel 11 via the drive shaft 15.

The battery 20 is, for example, a lithium ion secondary battery, a nickel hydrogen secondary battery, or the like, and is a rechargeable DC power source. The inverter 22 is electrically connected to the MG 12 and the battery 20. The inverter 22 converts the DC power output from the battery 20 into AC power and supplies it to the MG 12. The inverter 22 converts the AC power generated by the MG 12 into DC power and supplies it to the battery 20.

The hybrid vehicle 100 is driven by the internal combustion engine 10 and the MG 12. When the clutch 13 is in the open state, the output of the internal combustion engine 10 is not transmitted to the subsequent stage after the clutch 13. When the clutch 13 is engaged, the output of the internal combustion engine 10 is transmitted to the wheels 11 via the transmission 14, the differential gear 16 and the drive shaft 15. The hybrid vehicle 100 may travel only by driving the internal combustion engine 10. The MG 12 may be driven by the electric power supplied from the battery 20, and the hybrid vehicle 100 may travel using the output of the MG 12. By transmitting a part of the output of the internal combustion engine 10 to the MG 12, the MG 12 can be rotated to generate electricity by the MG 12. The electric power generated by the MG 12 is converted into DC electric power by the inverter 22 and stored in the battery 20.

The accelerator opening sensor 30 is connected to an accelerator pedal (not shown) to detect the accelerator opening. The rotation speed sensor 32 detects the rotation speed of the internal combustion engine 10. The air flow meter 34 detects the amount of air sucked into the internal combustion engine 10.

The HVECU 40, the engine ECU 42, the motor ECU 44, and the battery ECU 46 are control devices including a computing device such as a CPU (Central Processing Unit) and a storage device such as a ROM (Read Only Memory) and a RAM (Random Access Memory), respectively.

The HVECU 40 is connected to the engine ECU 42, the motor ECU 44, and the battery ECU 46, and controls, for example, the output (power) of the internal combustion engine 10 and the output of the MG 12 during OBD. The engine ECU 42 controls the internal combustion engine 10 based on a command from the HVE ECU 40 or the like. The motor ECU 44 controls the MG 12 based on a command from the HVE ECU 40 or the like. The battery ECU 46 controls the battery 20 based on a command from the HVE ECU 40, for example, monitors the charge rate (SOC: State of Charge) of the battery 20, and adjusts the power output by the battery 20.

The HVECU 40 acquires the accelerator opening degree from the accelerator opening degree sensor 30, the rotation speed of the internal combustion engine 10 from the rotation speed sensor 32, and the air amount from the air flow meter 34. The HVECU 40 acquires the load factor of the internal combustion engine 10 based on the accelerator opening degree, the number of revolutions, the amount of air, and the like. The load factor corresponds to the output of the internal combustion engine 10. For example, the higher the load factor, the larger the output.

The HVECU 40 controls the output of the internal combustion engine 10 by controlling the load factor of the internal combustion engine 10 during OBD, and keeps the output within an appropriate range. The HVECU 40 functions as a change amount acquisition unit that acquires a change amount of the output of the internal combustion engine 10, a threshold value setting unit that determines a threshold value for the change amount, and an output control unit that sets an output change amount to change the output. The HVECU 40 determines the required value according to, for example, the operation of the MG 12 during OBD. When the MG 12 performs power running during OBD, the HVECU 40 sets the required value Pe as a negative value, and when the MG 12 charges, the required value Pe is set as a positive value. In the present embodiment, the HVECU 40 can acquire the amount of change in the output by requesting the amount of change in the output of the internal combustion engine 10 and acquiring the required value Pe of the amount of change. As another embodiment, the HVECU 40 may request the output itself, not the amount of change in the output of the internal combustion engine 10. In this case, the HVECU 40 can acquire the amount of change in the output of the internal combustion engine 10 by calculating the difference between the required value of the output of the internal combustion engine 10 and the current output of the internal combustion engine 10. The threshold value of the amount of change is a value that is an upper limit and a lower limit of the amount of change, and is determined according to the rotation speed of the internal combustion engine 10 and the gear ratio of the transmission 14 as shown in FIG. 2 (b) described later. The HVECU 40 determines the amount of change in output by comparing the required value with the threshold value.

FIG. 2A is a time chart at the time of OBD implementation. From the top, the vehicle speed, accelerator opening, the number of revolutions of the internal combustion engine 10, the gear ratio (shift) of the transmission 14, the output of the MG 12, the load factor, and the amount of air are shown. In the example of FIG. 2 (a), the shift is constant. The output of MG12 shall take a positive value on the charging side and a negative value on the power running side. The solid lines in the output, load factor and air volume of MG12 are thresholds for each quantity. The broken line represents the required value. When the required value is smaller than the threshold value, the output, load factor, and air amount of MG12 become the respective required values. When the required value is equal to or higher than the threshold value, the output, load factor, and air amount of MG12 are limited to the respective threshold values.

FIG. 2B is a diagram showing a threshold value of the amount of change in the output of the internal combustion engine 10. The horizontal axis is the rotation speed of the internal combustion engine 10. The left side of the horizontal axis has a low rotation speed, and the right side has a high rotation speed. The vertical axis is the gear ratio (shift) of the transmission 14. The lower side is the lower shift, and the upper side is the higher shift.

As shown in FIG. 2B, the higher the rotation speed and the higher the shift, the higher the threshold Peth. When the rotation speed is less than R1 and the shift is less than S1, the threshold value Peth is Pa. When the rotation speed is R1 or more and less than R2, and the shift is S1 or more and less than S2, the threshold value Peth is Pb larger than Pa. When the rotation speed is R2 or more and the shift is S2 or more, the threshold value Peth is Pc larger than Pb.

The threshold value Peth is a value for suppressing deterioration of drivability during OBD. For example, if the amount of increase in output exceeds the threshold value Peth, the torque increases, and the hybrid vehicle 100 may accelerate unintentionally by the driver. Further, if the amount of decrease in output exceeds the threshold value Peth, the torque decreases, and the hybrid vehicle 100 may decelerate unintentionally by the driver. As a result, drivability during OBD deteriorates. Deterioration of drivability can be suppressed by the process of FIG.

FIG. 3 is a flowchart in the embodiment. The process of FIG. 3 is repeatedly executed, for example, during OBD. The HVECU 40 acquires the required value Pe of the amount of change in the output of the internal combustion engine 10 as compared with that before the execution of the process, for example, according to the operation of the MG 12, the rotation speed of the internal combustion engine 10, the accelerator opening, and the like (step S10). For example, when MG12 powers out during OBD, the required value Pe is negative, and when MG12 charges, the required value Pe is positive.

As shown in FIG. 2B, the HVECU 40 sets the threshold value Peth according to the rotation speed of the internal combustion engine 10 and the shift of the transmission 14 (step S12). Based on the threshold value Peth, the HVECU 40 has a range of the amount of change in the load factor of −Peth or more and Peth or less.

The HVECU 40 determines whether or not the absolute value of the required value Pe is smaller than the threshold value Peth (step S14). When the absolute value of the required value Pe is smaller than the threshold value Peth (affirmative determination, Yes), the HVECU 40 sets the change amount ΔP of the output of the internal combustion engine 10 to the required value Pe and changes the output (step S16). The load factor and the amount of air are the required values shown in FIG. 2 (a). On the other hand, when the absolute value of the required value Pe is equal to or greater than the threshold value Peth (negative determination, No), the HVECU 40 sets the output change amount ΔP to the threshold value Peth and changes the output (step S18). The load factor and the amount of air are the threshold values shown in FIG. 2 (a). The output of the internal combustion engine 10 after the change amount ΔP in steps S16 and S16 is large enough to execute the OBD of the internal combustion engine 10.

The HVECU 40 determines whether or not the absolute value of the change amount ΔP of the output of the internal combustion engine 10 is smaller than the threshold value Pmth of the output of the MG 12 (step S20). When the absolute value of the change amount ΔP is smaller than the threshold value Pmth (affirmative determination, Yes), the HVECU 40 sets the output of the MG 12 to the same magnitude as the change amount ΔP (step S22). When the absolute value of the amount of change ΔP is equal to or greater than the threshold value Pmth (negative determination, No), the HVECU 40 sets the output of the MG 12 as the threshold value Pmth (step S24). This completes the process.

According to the present embodiment, the HVECU 40 defines a required value Pe of the amount of change in the output of the internal combustion engine 10 and a threshold value Peth. When the absolute value of the required value Pe is smaller than the threshold value Peth, the HVECU 40 allows a change in the output, and the change amount ΔP is set to Pe. When the absolute value of the requested value Pe is larger than the threshold value Peth, the HVECU 40 sets the output change amount ΔP as the threshold value Peth. The HVECU 40 changes the output of the internal combustion engine 10 by the amount of change ΔP. By changing the output by the amount of change ΔP, it is possible to secure an OBD detection opportunity. Since the output change amount ΔP is within the range of −Peth or more and Peth or less, a sudden change in the output of the internal combustion engine 10 is suppressed. Unintentional acceleration and deceleration of the driver during OBD are suppressed, and drivability can be improved.

As shown in FIG. 2B, the HVECU 40 determines the threshold value Peth based on the rotation speed of the internal combustion engine 10 and the shift of the transmission 14. The absolute value of the amount of change in the output of the internal combustion engine 10 is equal to or less than the threshold value Peth. Therefore, deterioration of drivability can be suppressed according to the shift at the time of OBD implementation. The transmission 14 may be a stepped transmission or a continuously variable transmission (CVT). When the transmission 14 is a stepped transmission, the HVECU 40 determines the threshold value Peth based on the gear ratio determined by the shift lever. In the case of CVT, the HVECU 40 may set the threshold value Peth based on the gear ratio, the oil pressure of the sleeve, or the like.

In steps S14 to S18 of FIG. 3, the HVECU 40 determines, for example, a required value and a threshold value for the amount of change in the load factor, and can use these to keep the load factor within a predetermined range. In addition to the load factor, the HVECU 40 may control parameters related to the output of the internal combustion engine 10 within a predetermined range. The HVECU 40 may set the upper limit and the lower limit of the output separately.

The HVECU 40 sets the output of the MG 12 within the range of −Pmth or more and Pmth or less (steps S20 to S24 in FIG. 3). It is possible to suppress fluctuations in torque due to power running and charging of MG12, and to suppress deterioration of drivability. In addition, the SOC of the battery 20 can be maintained at an appropriate size, and deterioration of the battery 20 can be suppressed. The hybrid vehicle 100 shown in FIG. 1 is equipped with one MG, but may be equipped with two or more MGs.

Although the preferred embodiments of the present invention have been described in detail above, the present invention is not limited to the specific embodiment, and various modifications and variations are made within the scope of the gist of the present invention described in the claims. It can be changed.

10 Internal combustion engine 11 Wheels 12 MG
13 Clutch 14 Transmission 15 Drive shaft 16 Differential gear 20 Battery 22 Inverter 30 Accelerator opening sensor 32 Rotation speed sensor 34 Air flow meter 40 HVECU
42 engine ECU
44 Motor ECU
46 Battery ECU
100 hybrid vehicle

Claims (1)

It ’s a vehicle control device.
The vehicle is connected to an internal combustion engine that is a drive source of the vehicle, an electric motor that is a drive source of the vehicle and can generate power using the output of the internal combustion engine, and the internal combustion engine and the electric motor. Has a transmission,
When the control device executes the abnormality determination of the internal combustion engine, the control device includes a change amount acquisition unit that acquires a change amount of the output of the internal combustion engine.
A threshold setting unit that sets a threshold value for a change in the output of the internal combustion engine according to the gear ratio of the transmission.
When the required value is less than the threshold value, the output of the internal combustion engine is allowed to change, and when the required value is equal to or more than the threshold value, the change amount of the output of the internal combustion engine is set to the threshold value. And, a vehicle control device.

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