JP6776812B2 - vehicle - Google Patents

Description

The present invention relates to a vehicle capable of automatically stopping and starting an engine.

Conventionally, in the engine automatic stop / restart device that controls the operation of the braking force holding device, a technique for operating the braking force holding device after the engine is automatically stopped in order to improve fuel efficiency has been proposed in Patent Document 1. ing.

Japanese Unexamined Patent Publication No. 2012-102647

However, in the conventional technique as proposed in Patent Document 1, the engine is stopped on a ramp, for example, when the operation of the brake pedal is quickly released or when the holding device itself cannot operate. Therefore, there is a possibility that the vehicle will slide down, and improvement is desired.

The present invention has been made to solve the above problems, and an object of the present invention is to provide a vehicle capable of suppressing the vehicle from sliding down while improving fuel efficiency.

The vehicle according to the present invention that solves the above problems has an engine and a motor generator, travels by the power output by at least one of the engine and the motor generator, and automatically stops the engine. In a possible vehicle, the braking force holding control unit that activates the function of holding the braking force regardless of the operating state of the braking operation device that brakes the vehicle, the control unit that controls the engine, and the vehicle are stopped. The control unit includes an inclination angle calculation unit for calculating the inclination angle of the road surface, and the operation amount of the braking operation device is determined based on the inclination angle when the vehicle is stopped on the inclination road. When the tilt angle is equal to or less than the stop threshold and the tilt angle is less than the reverse start angle at which the vehicle retracts only by the driving force of the motor generator, the engine is stopped and the operation amount of the braking operation device is larger than the stop threshold. When the function of holding the braking force is activated by the braking force holding control unit, the engine is stopped, and the stop threshold value is such that the tilt angle is larger than the backward start angle. The larger it is, the larger it is set .

The present invention can provide a vehicle capable of suppressing the vehicle from sliding down while improving fuel efficiency.

FIG. 1 is a configuration diagram showing a main part of a hybrid vehicle according to an embodiment of the present invention. FIG. 2 is a functional configuration diagram of a hybrid vehicle according to an embodiment of the present invention. FIG. 3 is a conceptual diagram showing a starting threshold map referred to by the hybrid vehicle according to the embodiment of the present invention. FIG. 4 is a conceptual diagram showing a stop threshold map referred to by the hybrid vehicle according to the embodiment of the present invention. FIG. 5 is a flowchart showing an engine starting operation of the hybrid vehicle according to the embodiment of the present invention. FIG. 6 is a flowchart showing an engine stop operation of the hybrid vehicle according to the embodiment of the present invention. FIG. 7 is a flowchart showing a hill hold operation operation of the hybrid vehicle according to the embodiment of the present invention.

The vehicle according to the embodiment of the present invention is a vehicle capable of automatically stopping the engine, and the braking force holding function for operating the function of holding the braking force regardless of the operating state of the braking operation device for braking the vehicle. It includes a control unit and a control unit that controls the engine, and the control unit indicates that when the vehicle is stopped on a ramp, at least the braking force holding control unit is operating the function of holding the braking force. The condition is to stop the engine. As a result, the vehicle according to the embodiment of the present invention can prevent the vehicle from sliding down while improving fuel efficiency.

Hereinafter, an example in which the vehicle according to the present invention is applied to a hybrid vehicle will be described with reference to the drawings.

As shown in FIG. 1, the hybrid vehicle 1 includes an HCU (Hybrid Control Unit) 10 that comprehensively controls an engine 2, a transmission 3, a motor generator 4, a drive wheel 5, and a hybrid vehicle 1 as an internal combustion engine. The ECM (Engine Control Module) 11 that controls the engine 2, the TCM (Transmission Control Module) 12 that controls the transmission 3, the ISGCM (Integrated Starter Generator Control Module) 13, the INVCM (Invertor Control Module) 14, and so on. It includes a low-voltage BMS (Battery Management System) 15 and a high-voltage BMS 16.

A plurality of cylinders are formed in the engine 2. In this embodiment, the engine 2 is configured to perform a series of four strokes including an intake stroke, a compression stroke, an expansion stroke, and an exhaust stroke for each cylinder.

An ISG (Integrated Starter Generator) 20 and a starter 21 are connected to the engine 2. The ISG 20 is connected to the crankshaft 18 of the engine 2 via a belt 22 or the like. The ISG 20 has a function of an electric motor that starts the engine 2 by rotating when electric power is supplied, and a function of a generator that converts the rotational force input from the crankshaft 18 into electric power.

In this embodiment, the ISG 20 functions as an electric motor under the control of the ISGCM 13, so that the engine 2 is restarted from the stopped state by the idling stop function. The ISG 20 can also assist the running of the hybrid vehicle 1 by functioning as an electric motor.

The starter 21 includes a motor (not shown) and a pinion gear. The starter 21 rotates the crankshaft 18 by rotating the motor to give the engine 2 a rotational force at the time of starting. In this way, the engine 2 is started by the starter 21 and restarted by the ISG 20 from the stopped state by the idling stop function.

The transmission 3 shifts the rotation output from the engine 2 and drives the drive wheels 5 via the drive shaft 23. The transmission 3 includes a constantly meshing type transmission mechanism 25 including a parallel shaft gear mechanism, a clutch 26 composed of a normally closed type dry clutch, a differential mechanism 27, and an actuator (not shown).

The transmission 3 is configured as a so-called AMT (Automated Manual Transmission), and the actuator controlled by the TCM 12 switches the shift stage in the transmission mechanism 25 and connects and disengages the clutch 26. The differential mechanism 27 transmits the power output by the transmission mechanism 25 to the drive shaft 23.

The motor generator 4 is connected to the differential mechanism 27 via a power transmission mechanism 28 such as a chain. The motor generator 4 functions as an electric motor.

As described above, the hybrid vehicle 1 constitutes a parallel hybrid system capable of using the power of both the engine 2 and the motor generator 4 to drive the vehicle, and at least one of the engine 2 and the motor generator 4 outputs the power. It is designed to run on power.

The motor generator 4 also functions as a generator, and generates electricity by traveling the hybrid vehicle 1. The motor generator 4 may be connected to any part of the power transmission path from the engine 2 to the drive wheels 5 so as to be able to transmit power, and does not necessarily have to be connected to the differential mechanism 27.

The hybrid vehicle 1 includes a first power storage device 30, a low voltage power pack 32 including a second power storage device 31, a high voltage power pack 34 including a third power storage device 33, a high voltage cable 35, and a low voltage cable 36. And have.

The first power storage device 30, the second power storage device 31, and the third power storage device 33 are composed of a rechargeable secondary battery. The first power storage device 30 is made of a lead battery. The second power storage device 31 is a power storage device having a higher output and a higher energy density than the first power storage device 30.

The second power storage device 31 can be charged in a shorter time than the first power storage device 30. In this embodiment, the second power storage device 31 is made of a lithium ion battery. The second power storage device 31 may be a nickel-metal hydride storage battery.

The first power storage device 30 and the second power storage device 31 are low-voltage batteries in which the number of cells and the like are set so as to generate an output voltage of about 12 V. The third power storage device 33 is made of, for example, a lithium ion battery.

The third power storage device 33 is a high-voltage battery in which the number of cells and the like are set so as to generate a higher voltage than the first power storage device 30 and the second power storage device 31, and for example, an output voltage of 100 V is generated. The state such as the remaining capacity of the third power storage device 33 is managed by the high voltage BMS 16.

The hybrid vehicle 1 is provided with a general load 37 as an electric load and a protected load 38. The general load 37 and the protected load 38 are electrical loads other than the starter 21 and the ISG 20.

The protected load 38 is an electric load that is always required to have a stable power supply. The protected load 38 includes a stability control device 38A that prevents the hybrid vehicle 1 from skidding, an electric power steering control device 38B that electrically assists the operating force of the steering wheels, and a headlight 38C. The protected load 38 also includes lamps and meters of an instrument panel (not shown) and a car navigation system.

The general load 37 is an electric load that is temporarily used without requiring a stable power supply as compared with the protected load 38. The general load 37 includes, for example, a wiper (not shown) and an electric cooling fan that blows cooling air to the engine 2.

The low-voltage power pack 32 has switches 40 and 41 and a low-voltage BMS 15 in addition to the second power storage device 31. The first power storage device 30 and the second power storage device 31 are connected via a low voltage cable 36 so as to be able to supply electric power to the starter 21, the ISG 20, the general load 37 as an electric load, and the protected load 38. There is. The first power storage device 30 and the second power storage device 31 are electrically connected in parallel to the protected load 38.

The switch 40 is provided on the low voltage cable 36 between the second power storage device 31 and the protected load 38. The switch 41 is provided in the low voltage cable 36 between the first power storage device 30 and the protected load 38.

The low-voltage BMS 15 controls the opening and closing of the switches 40 and 41 to control the charging / discharging of the second power storage device 31 and the power supply to the protected load 38. When the engine 2 is stopped due to idling stop, the low voltage BMS 15 closes the switch 40 and opens the switch 41 to supply electric power from the second power storage device 31 having high output and high energy density to the protected load 38. It is designed to supply.

The low-voltage BMS 15 is the first by closing the switch 40 and opening the switch 41 when the engine 2 is started by the starter 21 and when the engine 2 stopped by the idling stop control is restarted by the ISG 20. Power is supplied from the power storage device 30 to the starter 21 or the ISG 20. When the switch 40 is closed and the switch 41 is opened, power is also supplied from the first power storage device 30 to the general load 37.

As described above, the first power storage device 30 is adapted to supply at least electric power to the starter 21 and the ISG 20 as starting devices for starting the engine 2. The second power storage device 31 is adapted to supply at least power to the general load 37 and the protected load 38.

The second power storage device 31 is connected so as to be able to supply power to both the general load 37 and the protected load 38, but preferentially supplies power to the protected load 38, which is always required to have a stable power supply. The switches 40 and 41 are controlled by the low voltage BMS 15.

The low-voltage BMS 15 stabilizes the protected load 38 while considering the charging state (remaining charge) of the first power storage device 30 and the second power storage device 31 and the operation requirements for the general load 37 and the protected load 38. The switches 40 and 41 may be controlled differently from the above-described example in order to give priority to the operation.

The high-voltage power pack 34 has an inverter 45, an INVCM 14, and a high-voltage BMS 16 in addition to the third power storage device 33. The high-voltage power pack 34 is connected to the motor generator 4 so as to be able to supply electric power via the high-voltage cable 35.

The inverter 45 is controlled by the INVCM 14 to convert the AC power applied to the high voltage cable 35 and the DC power applied to the third power storage device 33 to each other. For example, when the motor generator 4 is driven, the INVCM 14 converts the DC power discharged by the third power storage device 33 into AC power by the inverter 45 and supplies it to the motor generator 4.

When the motor generator 4 is regenerated, the INVCM 14 converts the AC power generated by the motor generator 4 into DC power by the inverter 45 and charges the third power storage device 33.

The HCU10, ECM11, TCM12, ISGCM13, INVCM14, low-voltage BMS15, and high-voltage BMS16 each have a CPU (Central Processing Unit), a RAM (Random Access Memory), a ROM (Read Only Memory), and backup data. It consists of a computer unit having a flash memory for storing, an input port, and an output port.

The ROM of these computer units stores various constants, various maps, and the like, as well as programs for making the computer unit function as HCU10, ECM11, TCM12, ISGCM13, INVCM14, low-voltage BMS15, and high-voltage BMS16, respectively. ..

That is, when the CPU executes the program stored in the ROM using the RAM as the work area, these computer units are used as the HCU10, ECM11, TCM12, ISGCM13, INVCM14, low voltage BMS15, and high voltage BMS16 in this embodiment, respectively. Function.

In this embodiment, the ECM 11 is adapted to execute idling stop control. In this idling stop control, the ECM 11 stops the engine 2 when a predetermined stop condition is satisfied, and drives the ISG 20 via the ISGCM 13 to restart the engine 2 when the predetermined restart condition is satisfied. .. Therefore, unnecessary idling of the engine 2 is not performed, and the fuel efficiency of the hybrid vehicle 1 can be improved.

The hybrid vehicle 1 is provided with CAN communication lines 48 and 49 for forming an in-vehicle LAN (Local Area Network) conforming to a standard such as CAN (Controller Area Network).

The HCU 10 is connected to the INVCM 14 and the high voltage BMS 16 by a CAN communication line 48. The HCU 10, INVCM14, and high-voltage BMS16 mutually transmit and receive signals such as control signals via the CAN communication line 48.

The HCU 10 is connected to the ECM 11, TCM 12, ISGCM 13 and low voltage BMS 15 by a CAN communication line 49. The HCU10, ECM11, TCM12, ISGCM13 and low-voltage BMS15 mutually transmit and receive signals such as control signals via the CAN communication line 49.

In FIG. 2, the input port of the ECM 11 includes a vehicle speed sensor 61 that detects the vehicle speed and a brake stroke sensor 63 that detects the amount of operation of the brake pedal 62 as a braking operation device (hereinafter, also simply referred to as “brake stroke”). , Various sensors including an acceleration sensor 64 that detects the acceleration of the hybrid vehicle 1 are connected.

Various control objects including the hydraulic circuit 71 are connected to the output port of the ECM 11. Each sensor and each controlled object may not be directly connected to the ECM 11. That is, each sensor and each control target are connected to another computer unit such as the HCU 10, and the ECM 11 receives the detection result of each sensor from the corresponding computer unit, or controls each via the corresponding computer unit. You may control the objects.

A brake mechanism 72 is provided on the wheels including the drive wheels 5 of the hybrid vehicle 1 as a braking device for braking the hybrid vehicle 1. The hybrid vehicle 1 is provided with a brake stroke sensor 63 that functions as a braking operation state detecting unit that detects an operating state of the brake mechanism 72.

The ECM 11 controls the brake mechanism 72 by controlling an actuator (not shown) via the hydraulic circuit 71 according to the brake stroke detected by the brake stroke sensor 63.

The ECM 11 is a hybrid of a control unit 81 that controls the engine 2 and an inclination angle calculation unit 82 that calculates an inclination angle θ of the traveling surface of the hybrid vehicle 1 based on the detection result of the acceleration sensor 64, regardless of the brake stroke. It has a function as a braking force holding control unit 83 that executes a hill hold function for controlling the braking mechanism 72 so as to hold the braking force of the vehicle 1.

(Engine start control)
When the hybrid vehicle 1 is stopped while the engine 2 is stopped, the ECM 11 starts the engine 2 based on the operating state of the brake pedal 62 and the inclination angle θ.

Specifically, the ECM 11 determines the starting threshold value Sth with respect to the brake stroke according to the inclination angle θ, and starts the engine 2 when the brake stroke detected by the brake stroke sensor 63 becomes equal to or less than the starting threshold value Sth.

The ECM 11 refers to the starting threshold map as shown in FIG. 3 and determines the starting threshold Sth with respect to the brake stroke according to the inclination angle θ. In the start threshold map shown in FIG. 3, the inclination angle θ and the start threshold Sth are associated with each other.

In the start threshold map shown in FIG. 3, the start threshold Sth is associated with a constant value regardless of the inclination angle θ in the range of the reverse start angle θm or less in which the hybrid vehicle 1 retracts only by the driving force of the motor generator 4. Has been done.

The reverse start angle θm is the torque that can be output by the motor generator 4, the gear ratio of the power transmission path from the motor generator 4 to the drive wheels 5, and the driving force of the hybrid vehicle 1 calculated from the outer diameter of the drive wheels 4. It is determined based on the weight of the vehicle.

In the start threshold map shown in FIG. 3, in the range larger than the receding start angle θm, the start threshold Sth is associated with the start threshold Sth so as to increase as the inclination angle θ increases.

In the start threshold map shown in FIG. 3, in the range larger than the receding start angle θm, the start threshold Sth increases with a constant inclination as the inclination angle θ increases, but as the inclination angle θ increases, It suffices if it gradually increases.

As described above, when the hybrid vehicle 1 is stopped while the engine 2 is stopped, the ECM 11 determines the starting threshold value Sth with reference to the starting threshold value map shown in FIG. 3, and the brake stroke sensor. When the brake stroke detected by 63 becomes equal to or less than the starting threshold value Sth, the engine 2 is started.

(Hill hold function)
In FIG. 2, in the ECM11, when the vehicle speed detected by the vehicle speed sensor 61 is 0, the brake stroke detected by the brake stroke sensor 63 is larger than the constant value α, and the inclination angle θ is larger than the operating angle θh. If so, activate the hill hold function.

The operating angle θh is a threshold value of the inclination angle θ, and is a conforming value determined with a margin so as to be smaller than the receding start angle θm. The constant value α is a conforming value referred to for determining whether or not the brake pedal 62 is operated to keep the hybrid vehicle 1 in the stopped state.

After the engine 2 is started, the ECM 11 maintains the hill hold function in the operating state until it is determined that the hybrid vehicle 1 will not move backward even if the hill hold function is inactive.

That is, if the ECM 11 determines that the hybrid vehicle 1 will not move backward even if the hill hold function is inactive after the engine 2 is started, the ECM 11 sets the hill hold function in the inactive state.

The ECM 11 is the sum of the driving force required for the motor generator 4 (hereinafter, simply referred to as “motor driving force”) and the driving force required for the engine 2 (hereinafter, simply referred to as “engine driving force”). If the value is larger than the judgment value A, it is determined that the hybrid vehicle 1 will not move backward even if the hill hold function is inactive, and if it is smaller than the judgment value A, the hill hold function is inactive. , It is determined that the hybrid vehicle 1 retreats.

The determination value A represents the magnitude of the braking force applied to the hybrid vehicle 1 in the direction of travel. The ECM 11 calculates the determination value A in consideration of the inclination angle θ, the vehicle weight, and the frictional resistance such as rolling resistance.

As described above, when the hybrid vehicle 1 is stopped in the state where the inclination angle θ is larger than the operating angle θh, the ECM 11 activates the hill hold function, and after the engine 2 is started, the hybrid vehicle 1 retreats. If it is determined that the function will not be performed, the hill hold function is disabled.

Since the hybrid vehicle 1 may move backward between the time when the condition for starting the engine 2 is satisfied and the time when the output torque of the engine 2 is sufficiently increased, the ECM 11 is a condition for starting the engine 2. When is satisfied, the hill hold function is not put into the inactive state, and after it is determined that the hybrid vehicle 1 will not move backward after the engine 2 is started, the hill hold function is put into the inactive state.

(Engine stop control)
When the vehicle speed detected by the vehicle speed sensor 61 is 0 and the brake stroke detected by the brake stroke sensor 63 is larger than the stop threshold value Pth, the ECM 11 starts the engine 2 if the hill hold function is in the operating state. Stop it.

The ECM 11 refers to the stop threshold map as shown in FIG. 4, and determines the stop threshold Pth for the brake stroke according to the inclination angle θ. In the stop threshold map shown in FIG. 4, the inclination angle θ and the stop threshold Pth are associated with each other.

In the stop threshold map shown in FIG. 4, in the range of the receding start angle θm or less, the stop threshold Pth is associated with a constant value regardless of the inclination angle θ. On the other hand, in the range larger than the receding start angle θm, the stop threshold value Pth is associated so as to increase as the inclination angle θ increases.

In the stop threshold map shown in FIG. 4, in the range larger than the receding start angle θm, the stop threshold Pth increases with a constant inclination as the inclination angle θ increases, but as the inclination angle θ increases, It suffices if it gradually increases.

In the ECM11, when the vehicle speed detected by the vehicle speed sensor 61 is 0 and the brake stroke detected by the brake stroke sensor 63 is not larger than the stop threshold value Pth, the inclination angle θ is less than the reverse start angle θm. If so, the engine 2 is stopped.

The engine starting operation of the hybrid vehicle according to the embodiment of the present invention configured as described above will be described with reference to FIG. The engine starting operation described below is repeatedly executed while the hybrid vehicle 1 is stopped while the engine 2 is stopped.

First, in step S1, the ECM 11 determines whether or not the brake stroke detected by the brake stroke sensor 63 is equal to or less than the starting threshold value Sth. If it is determined that the brake stroke is not equal to or less than the starting threshold value Sth, the ECM 11 ends the engine starting operation. If it is determined that the brake stroke is equal to or less than the starting threshold value Sth, the ECM 11 executes the process of step S2.

In step S2, the ECM 11 starts the engine 2 if the engine 2 has not started. After executing the process of step S2, that is, after starting the engine 2, the ECM 11 executes the process of step S3.

In the process after step S3, the ECM 11 disables the hill hold function if it is not necessary to execute the hill hold function.

First, in step S3, the ECM 11 determines whether or not the hill hold function is in the operating state. If it is determined that the hill hold function is not in the operating state, the ECM 11 ends the engine starting operation. When it is determined that the hill hold function is in the operating state, the ECM 11 executes the process of step S4.

In step S4, the ECM 11 determines whether or not the value obtained by adding the motor driving force and the engine driving force is larger than the determination value A. That is, the ECM 11 determines whether or not the hybrid vehicle 1 does not move backward even when the hill hold function is inactive.

When it is determined that the value obtained by adding the motor driving force and the engine driving force is not larger than the determination value A, the ECM 11 executes the process of step S4. That is, when it is determined that the value obtained by adding the motor driving force and the engine driving force is not larger than the determination value A, the ECM 11 maintains the hill hold function in the operating state. In short, the ECM 11 maintains the hill hold function in the operating state when it determines that the hybrid vehicle 1 retreats with the hill hold function inactive.

When it is determined that the value obtained by adding the motor driving force and the engine driving force is larger than the determination value A, the ECM 11 executes the process of step S5. In step S5, the ECM 11 deactivates the hill hold function.

In short, the ECM 11 maintains the hill hold function in the operating state when it is determined that the hybrid vehicle 1 does not move backward even if the hill hold function is not activated. After executing the process of step S5, the ECM 11 ends the engine starting operation.

The engine stop operation of the hybrid vehicle according to the embodiment of the present invention will be described with reference to FIG. The engine stop operation described below is repeatedly executed while the ECM 11 is operating.

First, in step S11, the ECM 11 determines whether or not the hybrid vehicle 1 is stopped. That is, the ECM 11 determines whether or not the vehicle speed detected by the vehicle speed sensor 61 is 0.

If it is determined that the hybrid vehicle 1 has not stopped, the ECM 11 ends the engine stop operation. If it is determined that the hybrid vehicle 1 is stopped, the ECM 11 executes the process of step S12.

In step S12, the ECM 11 determines whether or not the brake stroke detected by the brake stroke sensor 63 is larger than the stop threshold value Pth. That is, the ECM 11 determines whether or not the brake pedal 62 has been turned on.

If it is determined that the brake stroke is larger than the stop threshold value Pth, the ECM 11 executes the process of step S13. That is, when it is determined that the brake pedal 62 has been turned on, the ECM 11 executes the process of step S13.

If it is determined that the brake stroke is not larger than the stop threshold value Pth, the ECM 11 executes the process of step S14. That is, when it is determined that the brake pedal 62 has not been turned on, the ECM 11 executes the process of step S14.

In step S13, the ECM 11 determines whether or not the hill hold function is in the operating state. That is, it is determined whether or not the hybrid vehicle 1 may move backward when the brake pedal 62 is turned off.

If it is determined that the hill hold function is not in the operating state, the ECM 11 ends the engine stop operation. When it is determined that the hill hold function is in the operating state, the ECM 11 executes the process of step S15.

In step S14, the ECM 11 determines whether or not the tilt angle θ is less than the receding start angle θm. That is, the ECM 11 determines whether or not the hybrid vehicle 1 does not move backward only by the driving force of the motor generator 4 when the brake pedal 62 is turned off.

When it is determined that the inclination angle θ is not less than the retreat start angle θm, the ECM 11 ends the engine stop operation. When it is determined that the inclination angle θ is less than the receding start angle θm, the ECM 11 executes the process of step S15.

In step S15, the ECM 11 stops the engine 2 if the engine 2 is not stopped. After executing the process of step S15, the ECM 11 ends the engine stop operation.

The hill hold operation operation of the hybrid vehicle according to the embodiment of the present invention will be described with reference to FIG. 7. The hill hold operation described below is repeatedly executed while the ECM 11 is operating.

First, in step S21, the ECM 11 determines whether or not the hybrid vehicle 1 is stopped. That is, the ECM 11 determines whether or not the vehicle speed detected by the vehicle speed sensor 61 is 0.

If it is determined that the hybrid vehicle 1 is not stopped, the ECM 11 ends the hill hold operation operation. If it is determined that the hybrid vehicle 1 is stopped, the ECM 11 executes the process of step S22.

In step S22, the ECM 11 determines whether or not the brake stroke detected by the brake stroke sensor 63 is larger than the constant value α. That is, the ECM 11 determines whether or not the brake pedal 62 is operated to stop the hybrid vehicle 1.

When it is determined that the brake stroke is not larger than the constant value α, the ECM 11 ends the hill hold operation operation. If it is determined that the brake stroke is larger than the constant value α, the ECM 11 executes the process of step S23.

In step S23, the ECM 11 determines whether or not the inclination angle θ is larger than the operating angle θh. That is, the ECM 11 determines whether or not the hybrid vehicle 1 is surely not retracted only by the driving force of the motor generator 4 when the brake pedal 62 is turned off.

When it is determined that the inclination angle θ is not larger than the operating angle θh, the ECM 11 ends the hill hold operating operation. When it is determined that the inclination angle θ is larger than the operating angle θh, the ECM 11 executes the process of step S24.

In step S24, the ECM 11 activates the hill hold function if the hill hold function is not in the operating state. After executing the process of step S24, the ECM 11 ends the hill hold operation operation.

As described above, in the hybrid vehicle according to the present embodiment, the engine 2 is automatically stopped on condition that the hill hold function is operating. Therefore, the brake pedal 62 is suddenly released after the automatic stop of the engine 2 to generate the engine. The engine torque may be insufficient until the restart of engine 2 is completed, or the hill hold function may not operate, so the braking force may not be maintained normally after the automatic stop of the engine 2 and the braking force may be insufficient. By doing so, it is possible to prevent the hybrid vehicle 1 from sliding down.

Further, in the hybrid vehicle according to the present embodiment, even if the brake pedal 62 is operated, the engine 2 is automatically stopped on condition that the hill hold function is operating. Therefore, the hybrid vehicle 1 is automatically stopped after the engine 2 is automatically stopped. It is possible to prevent it from slipping down.

Further, in the hybrid vehicle according to the present embodiment, when the inclination angle θ of the stopped road surface is larger than the operating angle θh, the hill hold function is operating even if the brake pedal 62 is operated. Since the engine 2 is automatically stopped, it is possible to prevent the hybrid vehicle 1 from sliding down after the engine 2 is automatically stopped.

Further, in the hybrid vehicle according to the present embodiment, when the hybrid vehicle 1 is stopped while the engine 2 is stopped, the brake stroke detected by the brake stroke sensor 63 and the traveling surface of the hybrid vehicle 1 The engine is started based on the inclination angle θ of.

That is, the hybrid vehicle according to the present embodiment can improve the fuel efficiency of the engine 2 by executing the engine stop operation described with reference to FIG. Further, in the hybrid vehicle according to the present embodiment, since the brake stroke recognized as the off operation of the brake pedal 62 is changed according to the inclination angle θ of the traveling surface of the hybrid vehicle 1, the hybrid vehicle 1 does not depend on the inclination angle θ. It is possible to prevent the vehicle from slipping down. As described above, the hybrid vehicle according to the present embodiment can suppress the vehicle from sliding down while improving the fuel efficiency.

Further, in the hybrid vehicle according to the present embodiment, the starting threshold value Sth for the brake stroke is determined according to the inclination angle θ of the traveling surface of the hybrid vehicle 1 calculated based on the detection result of the acceleration sensor 64, and the brake stroke sensor 63. When the brake stroke detected by is equal to or less than the starting threshold Sth, the engine 2 is started. Therefore, in the hybrid vehicle according to the present embodiment, it is possible to prevent the hybrid vehicle 1 from sliding down regardless of the inclination angle θ.

Further, the hybrid vehicle according to the present embodiment has an inclination angle when the inclination angle θ of the traveling surface of the hybrid vehicle 1 is larger than the backward start angle θm in which the hybrid vehicle 1 retracts only by the driving force of the motor generator 4. The starting threshold Sth is determined so as to increase as θ increases.

Therefore, in the hybrid vehicle according to the present embodiment, as the inclination angle θ becomes larger, the engine 2 is started in a state where the brake stroke is larger, so that the hybrid vehicle 1 is prevented from sliding down regardless of the inclination angle θ. Can be done.

Further, in the hybrid vehicle according to the present embodiment, when the inclination angle θ of the traveling surface of the hybrid vehicle 1 is equal to or less than the reverse start angle θm, the start threshold value Sth is determined to be a constant value. Therefore, in the hybrid vehicle according to the present embodiment, when the hybrid vehicle 1 can be suppressed from sliding down only by the driving force of the motor generator 4, the engine 2 is not started unnecessarily, so that the fuel efficiency can be improved. ..

Further, the hybrid vehicle according to the present embodiment maintains the hill hold function in the operating state so as to maintain the braking force of the hybrid vehicle 1 until it is determined that the hybrid vehicle 1 will not move backward after the engine 2 is started. Therefore, it is possible to prevent the hybrid vehicle 1 from sliding down.

In this example, an example in which the brake pedal 62 is applied as the braking operation device has been described, but instead of the brake pedal 62, a brake lever or controller operated by hand like a welfare vehicle, or inside or outside the vehicle A controller capable of intervening in vehicle operation or the like, which allows the operating amount of the brake mechanism 72 to be operated by an occupant or an external operator, may be applied as the braking operation device. For example, a controller capable of intervening in vehicle operation regardless of whether inside or outside the vehicle includes a wireless controller or a touch panel.

Further, in this example, an example in which the starting threshold value Sth is determined with reference to the starting threshold value map as shown in FIG. 3 has been described, but the starting threshold value Sth may be a constant value. Further, in this example, an example in which the stop threshold value Pth is determined with reference to the stop threshold value map as shown in FIG. 4 has been described, but the stop threshold value Pth may be a constant value.

Further, in this embodiment, the ECM 11 has been described as having the functions of the control unit 81, the inclination angle calculation unit 82, and the braking force holding control unit 83, but the HCU10, TCM12, ISGCM13, INVCM14, low voltage BMS15, or high voltage Other controllers such as the BMS 16 may have any of the functions of the control unit 81, the inclination angle calculation unit 82, and the braking force holding control unit 83.

Further, in the present embodiment, an example in which the vehicle according to the present invention is applied to the hybrid vehicle 1 has been described, but the vehicle according to the present invention is a hybrid vehicle as long as it is a vehicle capable of automatically stopping or starting the engine. It can be applied to other than 1.

Although the examples of the present invention have been disclosed above, it is clear that the examples can be modified without departing from the scope of the present invention. The embodiments of the present invention are disclosed on the premise that the equivalents to which such modifications have been made are included in the invention described in the claims.

1 Hybrid vehicle (vehicle)
2 engine 4 motor generator (motor)
62 Brake pedal (braking operation device)
63 Brake stroke sensor (braking operation state detector)
72 Brake mechanism (braking device)
81 Control unit 82 Tilt angle calculation unit 83 Braking force holding control unit

Claims (1)

It has an engine and a motor generator,
In a vehicle that travels by power output by at least one of the engine and the motor generator and can automatically stop the engine.
A braking force holding control unit that activates a function of holding a braking force regardless of the operating state of the braking operation device that brakes the vehicle.
A control unit that controls the engine and
A tilt angle calculation unit for calculating the tilt angle of the road surface on which the vehicle is stopped is provided.
When the vehicle is stopped on a ramp, the control unit determines that the amount of operation of the braking operation device is equal to or less than the stop threshold determined based on the tilt angle, and the tilt angle is only the driving force of the motor generator. When the vehicle is less than the reverse start angle at which the vehicle reverses, the engine is stopped, the operation amount of the braking operation device is larger than the stop threshold value, and the braking force holding control unit operates a function of holding the braking force. If so, stop the engine and
The vehicle is characterized in that when the inclination angle is larger than the retreat start angle, the stop threshold value is set so as to increase as the inclination angle increases .

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