JP2018071419A - vehicle - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a vehicle which can improve fuel consumption while suppressing the vehicle from rolling down.SOLUTION: When a vehicle is stopped with the running of an engine stopped, the engine is started on the basis of a brake stroke detected by a brake stroke sensor which detects an operation amount of a brake pedal that operates brake force by a brake mechanism, and an angle of inclination of the vehicle, relative to a running surface, calculated from a detection result of an acceleration sensor.SELECTED DRAWING: Figure 5

Description

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

  Conventionally, in a hybrid vehicle driven by the power of an engine and a motor, when the engine is stopped automatically, the presence or absence of the engine start is determined based on the brake torque and the motor torque before the accelerator is depressed. Patent Document 1 proposes a technique for suppressing the amount of reverse of the vehicle when starting on a steep slope while improving fuel efficiency.

JP 2007-230288 A

  However, the conventional technology proposed in Patent Document 1 starts the engine when the brake is turned off regardless of the inclination angle. There was a problem that there was a risk of sliding down.

  The present invention has been made to solve the above-described 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.

  A vehicle according to the present invention that solves the above-mentioned problems is a vehicle capable of automatically stopping and starting an engine, a braking operation state detection unit that detects an operation state of a braking device that brakes the vehicle, An inclination angle calculation unit that calculates an inclination angle of a running surface; and a control unit that controls the engine, and the control unit is configured to stop the vehicle when the engine is stopped. The engine is started based on the operation state detected by the braking operation state detection unit and the inclination angle calculated by the inclination angle calculation unit.

  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 the hybrid vehicle according to the embodiment of the present invention. FIG. 3 is a conceptual diagram showing a start 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 the engine start operation of the hybrid vehicle according to the embodiment of the present invention. FIG. 6 is a flowchart showing the engine stop operation of the hybrid vehicle according to the embodiment of the present invention. FIG. 7 is a flowchart showing the hill hold operation of the hybrid vehicle according to the embodiment of the present invention.

  A vehicle according to an embodiment of the present invention includes a braking operation state detection unit that detects an operation state of a braking device that brakes the vehicle in a vehicle capable of automatically stopping and starting an engine, and a traveling surface of the vehicle. An inclination angle calculation unit that calculates an inclination angle of the engine and a control unit that controls the engine, and the control unit detects a braking operation state when the vehicle is stopped with the engine stopped. The engine is started based on the operation state detected by the above and the inclination angle calculated by the inclination angle calculation unit. Thereby, the vehicle according to the embodiment of the present invention can suppress the vehicle from sliding down while improving the fuel efficiency.

  Hereinafter, an example in which a 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, a hybrid vehicle 1 includes an engine 2 as an internal combustion engine, a transmission 3, a motor generator 4, drive wheels 5, and an HCU (Hybrid Control Unit) 10 that comprehensively controls the hybrid vehicle 1. An ECM (Engine Control Module) 11 that controls the engine 2, a TCM (Transmission Control Module) 12 that controls the transmission 3, an ISGCM (Integrated Starter Generator Control Module) 13, an INVCM (Invertor Control Module) 14, A low voltage BMS (Battery Management System) 15 and a high voltage BMS 16 are included.

  The engine 2 is formed with a plurality of cylinders. 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.

  The engine 2 is connected with an ISG (Integrated Starter Generator) 20 and a starter 21. 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 supplied with electric power, and a function of a generator that converts rotational force input from the crankshaft 18 into electric power.

  In this embodiment, the ISG 20 is configured to restart the engine 2 from a stop state by the idling stop function by functioning as an electric motor under the control of the ISGCM 13. The ISG 20 can also assist the traveling of the hybrid vehicle 1 by functioning as an electric motor.

  The starter 21 includes a motor and a pinion gear (not shown). The starter 21 rotates the crankshaft 18 by rotating the motor to give the engine 2 a starting torque. As described above, the engine 2 is started by the starter 21 and restarted by the ISG 20 from the stop 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 transmission mechanism 25 including a parallel shaft gear mechanism, a clutch 26 constituted by 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). The actuator controlled by the TCM 12 switches the gear position in the transmission mechanism 25 and connects and disengages the clutch 26. The differential mechanism 27 is configured to transmit the power output by the speed change 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.

  Thus, the hybrid vehicle 1 forms a parallel hybrid system that can use the power of both the engine 2 and the motor generator 4 for driving the vehicle, and at least one of the engine 2 and the motor generator 4 outputs. It is designed to run with power.

  The motor generator 4 also functions as a generator and generates power when the hybrid vehicle 1 travels. The motor generator 4 may be connected to any part of the power transmission path from the engine 2 to the drive wheel 5 so as to be able to transmit power, and is not necessarily 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.

  The 1st electrical storage apparatus 30, the 2nd electrical storage apparatus 31, and the 3rd electrical storage apparatus 33 are comprised from the rechargeable secondary battery. First power storage device 30 is formed of a lead battery. The second power storage device 31 is a power storage device with higher output and 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 the present embodiment, the second power storage device 31 is composed of a lithium ion battery. The second power storage device 31 may be a nickel 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 is set so as to generate an output voltage of about 12V. The 3rd electrical storage apparatus 33 consists of a lithium ion battery, for example.

  The third power storage device 33 is a high voltage battery in which the number of cells is set so as to generate a higher voltage than the first power storage device 30 and the second power storage device 31, and generates an output voltage of 100V, for example. 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 and a protected load 38 as electric loads. The general load 37 and the protected load 38 are electric loads other than the starter 21 and the ISG 20.

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

  The general load 37 is an electric load that is temporarily used without requiring 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 includes 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 to the starter 21, the ISG 20, the general load 37 as an electrical load, and the protected load 38 via a low voltage cable 36 so as to be able to supply power. Yes. 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 in 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 charging / discharging of the second power storage device 31 and power supply to the protected load 38 by controlling opening and closing of the switches 40 and 41. When the engine 2 is stopped due to idling stop, the low voltage BMS 15 closes the switch 40 and opens the switch 41, thereby supplying power from the second power storage device 31 having high output and high energy density to the protected load 38. It comes to supply.

  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, the low voltage BMS 15 opens the switch 41 and opens the switch 41. Electric 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 supplies at least electric power to the starter 21 and the ISG 20 as starters for starting the engine 2. The second power storage device 31 supplies 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. However, the second power storage device 31 preferentially supplies power to the protected load 38 for which stable power supply is always required. Thus, the switches 40 and 41 are controlled by the low voltage BMS 15.

  The low voltage BMS 15 stabilizes the protected load 38 while taking into account the charging state (remaining charge amount) of the first power storage device 30 and the second power storage device 31 and the operation requests to the general load 37 and the protected load 38. Therefore, the switches 40 and 41 may be controlled differently from the above-described example with priority given to operation.

  The high voltage power pack 34 includes an inverter 45, INVCM 14, and 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 via a high voltage cable 35 so that electric power can be supplied.

  The inverter 45 is configured to mutually convert AC power applied to the high voltage cable 35 and DC power applied to the third power storage device 33 under the control of the INVCM 14. For example, when powering the motor generator 4, the INVCM 14 converts the DC power discharged by the third power storage device 33 into AC power by the inverter 45 and supplies the AC power 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.

  HCU10, ECM11, TCM12, ISGCM13, INVCM14, low voltage BMS15 and high voltage BMS16 are respectively CPU (Central Processing Unit), RAM (Random Access Memory), ROM (Read Only Memory), backup data, etc. The computer unit includes a flash memory to be stored, an input port, and an output port.

  The ROMs of these computer units store various constants, various maps, etc., and programs for causing the computer units to function as the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, low voltage BMS 15 and high voltage BMS 16, respectively. .

  That is, when the CPU executes a program stored in the ROM using the RAM as a work area, these computer units are respectively referred to as the HCU 10, ECM 11, TCM 12, ISGCM 13, INVCM 14, low voltage BMS 15 and high voltage BMS 16 in this embodiment. Function.

  In this embodiment, the ECM 11 performs idling stop control. In this idling stop control, the ECM 11 stops the engine 2 when a predetermined stop condition is satisfied, and restarts the engine 2 by driving the ISG 20 via the ISGCM 13 when the predetermined restart condition is satisfied. . For this reason, 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, INVCM 14 and high voltage BMS 16 mutually transmit and receive signals such as control signals via the CAN communication line 48.

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

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

  Various control objects including the hydraulic circuit 71 are connected to the output port of the ECM 11. Each sensor and each control target do not need to 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 a detection result of each sensor from the corresponding computer unit, or controls each control via the corresponding computer unit. You may control objects.

  The wheels including the drive wheels 5 of the hybrid vehicle 1 are provided with a brake mechanism 72 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 detector that detects an operation 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 includes a control unit 81 that controls the engine 2, a tilt angle calculation unit 82 that calculates the tilt angle θ of the traveling surface of the hybrid vehicle 1 based on the detection result of the acceleration sensor 64, and a hybrid 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 brake mechanism 72 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 operation state of the brake pedal 62 and the inclination angle θ.

  Specifically, the ECM 11 determines a start threshold value Sth for 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 start threshold value Sth.

  The ECM 11 refers to a start threshold map as shown in FIG. 3 and determines a start threshold Sth for 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 where the hybrid vehicle 1 moves backward only with the driving force of the motor generator 4. It has been.

  The reverse start angle θm is the torque that the motor generator 4 can output, the speed 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 vehicle weight.

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

  In the starting threshold map shown in FIG. 3, in the range larger than the reverse start angle θm, the starting threshold Sth increases with a constant inclination as the inclination angle θ increases, but as the inclination angle θ increases. It only needs to gradually increase.

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

(Hill hold function)
In FIG. 2, the ECM 11 is such that the brake stroke detected by the brake stroke sensor 63 is larger than a fixed value α and the inclination angle θ is larger than the operating angle θh in a state where the vehicle speed detected by the vehicle speed sensor 61 is zero. For example, the hill hold function is activated.

  The operating angle θh is a conforming value determined with a margin so as to be smaller than the reverse start angle θm. The constant value α is a reference value that is referred to for determining whether or not the brake pedal 62 is operated in order to maintain the hybrid vehicle 1 in a stopped state.

  The ECM 11 maintains the hill hold function in the activated state until it is determined that the hybrid vehicle 1 will not move backward even if the hill hold function is deactivated after the engine 2 is started.

  That is, if the ECM 11 determines that the hybrid vehicle 1 does not move backward even if the hill hold function is deactivated after the engine 2 is started, the ECM 11 deactivates the hill hold function.

  The ECM 11 adds 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 determination value A, it is determined that the hybrid vehicle 1 will not move backward even if the hill hold function is deactivated. If the value is smaller than the determination value A, the hill hold function is deactivated. It is determined that the hybrid vehicle 1 moves backward.

  The determination value A represents the magnitude of the braking force applied against the hybrid vehicle 1 in the traveling direction. 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 stops in a state where the inclination angle θ is larger than the operating angle θh, the ECM 11 sets the hill hold function to the operating state, and the hybrid vehicle 1 moves backward after the engine 2 is started. If it is determined that it will not be performed, the hill hold function is deactivated.

  Since the hybrid vehicle 1 may move backward from when the condition for starting the engine 2 is established to when the output torque of the engine 2 sufficiently increases, the ECM 11 sets the condition for starting the engine 2. After the engine 2 is started without determining that the hill hold function is not activated when the condition is established, the hill hold function is deactivated after determining that the hybrid vehicle 1 will not move backward.

(Engine stop control)
If the vehicle speed detected by the vehicle speed sensor 61 is 0 and the brake stroke detected by the brake stroke sensor 63 is greater than the stop threshold value Pth, the ECM 11 Stop.

  The ECM 11 refers to a stop threshold map as shown in FIG. 4 and determines a 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, the stop threshold Pth is associated with a constant value regardless of the inclination angle θ in the range of the reverse start angle θm or less. On the other hand, in the range larger than the reverse 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 reverse 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 only needs to gradually increase.

  If 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 ECM 11 may have the inclination angle θ less than the reverse start angle θm. 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 start threshold value Sth. If it is determined that the brake stroke is not equal to or less than the start threshold value Sth, the ECM 11 ends the engine start operation. When it is determined that the brake stroke is equal to or less than the start 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 is 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 processing after step S3, the ECM 11 deactivates 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 activated. If it is determined that the hill hold function is not activated, the ECM 11 ends the engine start operation. If it is determined that the hill hold function is in the activated 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. In other words, the ECM 11 determines whether or not the hybrid vehicle 1 is not retracted even when the hill hold function is deactivated.

  If the ECM 11 determines that the sum of the motor driving force and the engine driving force is not greater than the determination value A, the ECM 11 executes the process of step S4. That is, when it is determined that the sum of the motor driving force and the engine driving force is not greater than the determination value A, the ECM 11 maintains the hill hold function in the operating state. In short, when the ECM 11 determines that the hybrid vehicle 1 moves backward with the hill hold function in the non-operating state, the ECM 11 maintains the hill hold function in the operating state.

  If the ECM 11 determines that the sum of the motor driving force and the engine driving force is greater 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, when the ECM 11 determines that the hybrid vehicle 1 does not move backward even when the hill hold function is deactivated, the ECM 11 maintains the hill hold function in the activated state. After executing the process of step S5, the ECM 11 ends the engine start 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 zero.

  When it is determined that the hybrid vehicle 1 is 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 greater than the stop threshold value Pth. That is, the ECM 11 determines whether or not the brake pedal 62 is turned on.

  If it is determined that the brake stroke is greater 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 is turned on, the ECM 11 executes the process of step S13.

  If it is determined that the brake stroke is not greater than the stop threshold value Pth, the ECM 11 executes the process of step S14. That is, if it is determined that the brake pedal 62 is not 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 activated. 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 activated, the ECM 11 ends the engine stop operation. If it is determined that the hill hold function is in the activated state, the ECM 11 executes the process of step S15.

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

  If it is determined that the inclination angle θ is not less than the reverse start angle θm, the ECM 11 ends the engine stop operation. When it is determined that the inclination angle θ is less than the reverse 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 of the hybrid vehicle according to the embodiment of the present invention will be described with reference to FIG. 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 zero.

  If it is determined that the hybrid vehicle 1 has not stopped, the ECM 11 ends the hill hold 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 greater than a certain value α. That is, the ECM 11 determines whether or not the brake pedal 62 is operated to stop the hybrid vehicle 1.

  If it is determined that the brake stroke is not greater than the constant value α, the ECM 11 ends the hill hold operation. If it is determined that the brake stroke is greater than the certain 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 reliably moved backward only by the driving force of the motor generator 4 when the brake pedal 62 is turned off.

  If it is determined that the inclination angle θ is not greater than the operating angle θh, the ECM 11 ends the hill hold operating operation. If 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 activated. After executing the process of step S24, the ECM 11 ends the hill hold operation.

  As described above, 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 hybrid vehicle 1 are reduced. The engine is started based on the inclination angle θ of the traveling surface.

  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. In addition, the hybrid vehicle according to the present embodiment changes the brake stroke recognized as an off operation of the brake pedal 62 according to the inclination angle θ of the traveling surface of the hybrid vehicle 1, so that the hybrid vehicle 1 does not depend on the inclination angle θ. It is possible to suppress the sliding down. Thus, the hybrid vehicle according to the present embodiment can suppress the vehicle from sliding down while improving the fuel efficiency.

  Further, the hybrid vehicle according to the present embodiment determines the starting threshold value Sth for the brake stroke 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 the above becomes equal to or less than the start threshold Sth, the engine 2 is started. For this reason, the hybrid vehicle which concerns on a present Example can suppress that the hybrid vehicle 1 slips down irrespective of inclination-angle (theta).

  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 reverse start angle θm at which the hybrid vehicle 1 moves backward only by the driving force of the motor generator 4. The starting threshold value Sth is determined so as to increase as θ increases.

  Therefore, in the hybrid vehicle according to the present embodiment, as the tilt angle θ increases, the engine 2 is started in a state where the brake stroke is large, so that the hybrid vehicle 1 is prevented from sliding down regardless of the tilt angle θ. Can do.

  Further, the hybrid vehicle according to the present embodiment determines the starting threshold value Sth as a constant value when the inclination angle θ of the traveling surface of the hybrid vehicle 1 is equal to or smaller than the reverse start angle θm. For this reason, the hybrid vehicle according to the present embodiment does not unnecessarily start the engine 2 when the hybrid vehicle 1 can be prevented from sliding down only by the driving force of the motor generator 4, so that the fuel consumption can be improved. .

  Further, the hybrid vehicle according to the present embodiment maintains the hill hold function in the operating state so as to hold 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 suppress the hybrid vehicle 1 from sliding down.

  In this example, an example in which the brake pedal 62 is applied as a brake force of the brake mechanism 72 serving as a braking device has been described. However, the brake pedal 62 is replaced with a hand operated like a welfare vehicle. A brake lever or controller that can operate the amount of operation of the brake mechanism 72 by an occupant or an external operator, such as a controller that can intervene in vehicle operation regardless of inside or outside the vehicle, may be applied. For example, a controller that can intervene in the vehicle operation regardless of inside or outside the vehicle includes a wireless controller or a touch panel.

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

  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. However, the HCU 10, the TCM 12, the ISGCM 13, the INVCM 14, the low voltage BMS 15, or the high voltage Other controllers such as the BMS 16 may have any function as the control unit 81, the inclination angle calculation unit 82, and the braking force holding control unit 83.

  Further, in the present embodiment, the example in which the vehicle according to the present invention is applied to the hybrid vehicle 1 has been described. However, the vehicle according to the present invention is a hybrid vehicle as long as the engine can be automatically stopped or started. It can be applied to other than 1.

  Although the embodiments of the present invention have been disclosed above, it is obvious that changes can be made to the embodiments without departing from the scope of the present invention. The embodiments of the present invention are disclosed on the assumption that equivalents with such modifications are included in the invention described in the claims.

1 Hybrid vehicle (vehicle)
2 Engine 4 Motor generator (motor)
62 Brake pedal 63 Brake stroke sensor (braking operation state detector)
72 Brake mechanism (braking device)
81 Control Unit 82 Inclination Angle Calculation Unit 83 Braking Force Holding Control Unit

Claims (5)

In a vehicle that can automatically stop and start the engine,
A braking operation state detection unit that detects an operation state of a braking device that brakes the vehicle;
An inclination angle calculation unit for calculating an inclination angle of the traveling surface of the vehicle;
A control unit for controlling the engine,
When the vehicle is stopped while the engine is stopped, the control unit detects the operation state detected by the braking operation state detection unit and the inclination angle calculated by the inclination angle calculation unit. And starting the engine based on the above. The braking operation state detection unit detects an operation amount of a brake pedal,
The control unit determines a threshold value for the operation amount of the brake pedal according to the inclination angle calculated by the inclination angle calculation unit, and the operation amount of the brake pedal detected by the braking operation state detection unit is the threshold value. 2. The vehicle according to claim 1, wherein the engine is started when the following conditions are met. The vehicle is a vehicle that uses an engine and a motor as drive sources, starts the engine according to a running state, and travels with the driving force of the motor and the engine,
When the inclination angle calculated by the inclination angle calculation unit is larger than the retreat start angle at which the vehicle moves backward only by the driving force of the motor, the control unit calculates the inclination calculated by the inclination angle calculation unit. The vehicle according to claim 2, wherein the threshold value is determined so as to increase as the angle increases.   The vehicle according to claim 3, wherein the control unit determines the threshold value to be a constant value when the inclination angle calculated by the inclination angle calculation unit is equal to or less than the reverse start angle. A braking force holding control unit that controls the braking device to hold the braking force of the vehicle regardless of the operation amount of the brake pedal;
3. The braking device according to claim 2, wherein the braking force holding control unit controls the braking device to hold the braking force of the vehicle until it is determined that the vehicle does not move backward after the engine is started. The vehicle according to any one of claims 1 to 4.

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