JP2015058926A - Hybrid vehicle and control method for the same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a hybrid vehicle which can reduce tiredness of a driver by alleviating the change of the deceleration on an operation stop of an auxiliary brake and extend the life of parts, e.g. a brake lining and a pad of the service brake and its control method.SOLUTION: A hybrid vehicle 1 which is mounted with both an internal engine 11 and a motor generator 21 and causes an auxiliary brake to be in a non-operation condition during deceleration when the engine is in a low-rotation condition is provided with brake operation stop detection means 41a of detecting an operation stop of the auxiliary brake during deceleration and a brake force auxiliary controller 41 which controls so as to cause the motor generator 21 to undergo a regeneration operation when an operation stop of the auxiliary brake during deceleration is detected.

Description

  The present invention can reduce a driver's fatigue by reducing a change in deceleration when the auxiliary brake is stopped during deceleration, and can extend the life of parts such as a main brake lining and pads. The present invention relates to a vehicle and a control method thereof.

  In a hybrid vehicle (HEV) equipped with both an internal combustion engine and a motor generator, the motor generator is driven by the output of the internal combustion engine to generate power, and the generated power is charged into a battery or charged into this battery. The motor generator is driven by electric power to assist the output of the internal combustion engine.

  On the other hand, in large vehicles such as trucks, the exhaust brake (exhaust brake) can generate braking force on the internal combustion engine side because the capacity of the main brake, which consists of disc brakes, is relatively small compared to the vehicle weight. An auxiliary brake such as a compression release brake is employed (for example, Patent Document 1).

  However, this exhaust brake has a problem that it cannot be operated at an engine speed slightly lower than the idling speed due to engine stall restrictions. Also, in the compression release brake, a valve for releasing air compression in the cylinder is not provided. Since the operation is performed by the hydraulic actuator, the operation is canceled when the pressure of the hydraulic oil is equal to or lower than the engine speed at which the hydraulic pressure is lower than the minimum operating hydraulic pressure.

  Therefore, when these auxiliary brakes are used and the engine speed decreases during deceleration and falls below these engine speeds, the operation of the auxiliary brake is stopped. Will loosen suddenly. For this reason, the driver (driver) feels the feeling of running away and the brakes missing due to insufficient braking force.

JP 2008-286206 A

  The present invention has been made in view of the above, and an object of the present invention is to provide a hybrid vehicle that is equipped with both an internal combustion engine and a motor generator and is inoperative when the auxiliary brake is at a low engine speed during deceleration. Is to alleviate the change in deceleration when the auxiliary brake is deactivated.

  In order to achieve the above object, a hybrid vehicle according to the present invention is equipped with both an internal combustion engine and a motor generator, and in a hybrid vehicle that is inoperative when the auxiliary brake is at low engine speed during deceleration, Brake operation stop detecting means for detecting the stop of operation of the auxiliary brake, and a control device for a hybrid system that performs control to regenerate the motor generator when the stop of operation of the auxiliary brake is detected during deceleration. Configured.

  In the hybrid vehicle described above, the hybrid system control device is configured to perform a control to generate a regenerative torque having the same magnitude as the braking torque of the auxiliary brake when the stop of the auxiliary brake is detected. The

  Further, in the above hybrid vehicle, when the brake operation stop detection means sets the rotation speed at which the auxiliary brake is stopped as the operation stop rotation speed, and the engine rotation speed becomes equal to or less than the operation stop rotation speed Further, it is configured that the stop of the operation of the auxiliary brake is detected.

  In the hybrid vehicle described above, it is more effective when the auxiliary brake is configured to include at least one of an exhaust brake and a compression release brake.

  And the hybrid vehicle control method of the present invention for achieving the above object is equipped with both an internal combustion engine and a motor generator, and the hybrid vehicle is inactivated when the auxiliary brake is at low engine speed during deceleration. In this control method, when detecting the stop of operation of the auxiliary brake during deceleration, the motor generator is regenerated to generate regenerative torque that substitutes for deceleration torque by the auxiliary brake. It is a method to do.

  In the above hybrid vehicle control method, control is performed to generate a regenerative torque having the same magnitude as the braking torque of the auxiliary brake when the stop of the operation of the auxiliary brake is detected.

  In the hybrid vehicle control method described above, it is assumed that the operation stop of the auxiliary brake is detected when the engine speed becomes equal to or lower than the operation stop speed that is the lower limit value at which the auxiliary brake can be operated.

  In the hybrid vehicle control method, the auxiliary brake includes at least one of an exhaust brake and a compression release brake.

  According to the hybrid vehicle of the present invention and the control method therefor, in the hybrid vehicle equipped with both the internal combustion engine and the motor generator and inactivated during the deceleration of the engine during the deceleration, the operation of the auxiliary brake is performed. The change in deceleration at the time of stoppage can be alleviated to reduce driver fatigue, and the life of parts such as brake lining and pads of the main brake can be extended.

It is a figure which shows the structure of the hybrid vehicle of embodiment of this invention. It is a figure which shows an example of the control flow of the control method of the hybrid system of embodiment of this invention. It is a figure which shows the other example of the control flow of the control method of the hybrid system of embodiment of this invention.

  Hereinafter, a hybrid vehicle and a control method thereof according to embodiments of the present invention will be described. As illustrated in FIG. 1, the hybrid vehicle of this embodiment is equipped with both an engine (internal combustion engine) 11 and a motor generator 21 and includes at least one of an exhaust brake and a compression release brake during deceleration. A hybrid vehicle 1 that uses a brake.

  The hybrid system 2 includes an engine (ENG) 11 and a motor generator (M / G) 21. The engine 11 includes an exhaust passage 12, a turbocharger 13, and an exhaust gas purification device 14. And an exhaust brake valve 17 and further includes a compression release brake (not shown).

  This exhaust brake (exhaust brake) closes the exhaust brake valve 17 provided in the middle of the exhaust passage 12 to increase the exhaust pressure and increase the pumping loss applied to the cylinder, thereby resisting the rotation of the crankshaft 15. Has produced.

  On the other hand, the compression release brake is also called a Jake brake, and is a type of engine brake that uses the compression stroke of the cylinder of the engine 11. When the piston reaches the top dead center in the compression stroke of the engine 11, fuel injection is performed. This is a mechanism that opens the exhaust valve and releases the air compression in the cylinder without performing the operation.If the exhaust valve is closed after passing through the top dead center, the pressure in the cylinder decreases as the piston descends. This is a resistance against the rotation of the shaft 15.

  In the configuration illustrated in FIG. 1, the hybrid system 2 has a motor generator 21 connected to a CVT (continuously variable transmission mechanism: ratio variable mechanism) 16 provided directly connected to the crankshaft 15 of the engine 11. The CVT 16 includes an endless belt or chain between the first pulley (first power transmission unit) 16a on the crankshaft 15 side and the second pulley (second power transmission unit) 16b on the motor generator 21 side. The power transmission member 16c formed by is wound around, and power is transmitted between the crankshaft 15 and the motor generator 21 through these members.

  And the motor generator 21 which is a part of the electric power system 20 receives the driving force of the engine 11 as a generator and generates electric power, or generates regenerative power by generating regenerative power such as braking force of the vehicle 1. In addition, the motor is driven as a motor and the driving force is transmitted to the crankshaft 15 of the engine 11 to assist the driving force (output: torque) of the engine 11.

  The electric power generated by the power generation is converted by the inverter (INV) 23 via the wiring 22 and charged in the first battery (charger: B1) 24A. When driving the motor generator 21, the electric power charged in the first battery 24 </ b> A is converted by the inverter 23 and supplied to the motor generator 21.

  In the configuration of FIG. 1, a DC-DC converter (CON) 25 and a second battery (B2) 24B are further provided in series with the first battery 24A. In the DC-DC converter 25, for example, the voltage is dropped to 12 V and charged to the second battery 24B, and the auxiliary battery cooling fan 26A, cooling water pump 26B, Electric power is supplied to the lubricating oil pump 26C and the like.

  The power of the engine 11 is transmitted to the wheels 35 through the transmission 31, the propulsion shaft 32, the differential device 33, and the drive shaft 34 of the power transmission system 30, and the vehicle 1 travels. Depending on how the engine 11 is mounted, the power transmission path from the engine 11 to the wheel 35 may be different.

  On the other hand, regarding the power of the motor generator 21, the power charged in the first battery 24A is supplied to the motor generator 21 via the inverter 23, and the power of the motor generator 21 generated by this power is transmitted via the CVT 16. Is transmitted to the crankshaft 15, transmitted through the power transmission path of the engine 11, and transmitted to the wheels 35. Thereby, the motive power of the motor generator 21 is transmitted to the wheels 35 together with the motive power of the engine 11, and the vehicle 1 travels. During regeneration, the regenerative power of the wheels 35 or the regenerative power of the engine 11 is transmitted to the motor generator 21 through the reverse path, and the motor generator 21 can generate power.

  Also, a hybrid system control device 41 is provided, and the operating state such as the rotational speed Ne and the load Q of the engine 11 and the operating state such as the rotational speed Na of the motor generator 21 and the charging of the first battery 24A and the second battery 24B. While monitoring the quantity (SOC) state, the CVT 16, the motor generator 21, the inverter 23, the DC-DC converter 25, and the like are controlled.

  The hybrid system control device 41 is usually configured to be incorporated in an overall control device 40 that controls the engine 11 and the vehicle 1. The overall control device 40 controls the combustion in the cylinder, the turbocharger 13, the exhaust gas purification device 14, the cooling fan 26A of the auxiliary machine, the cooling water pump 26B, the lubricating oil pump 26C and the like in the control of the engine 11. Yes.

  In the present invention, the hybrid system control device 41 includes a brake operation stop detection means 41a for detecting the stop of the operation of the auxiliary brake during the deceleration, and when detecting the stop of the operation of the auxiliary brake during the deceleration, The motor generator 21 is regeneratively operated so as to perform control to generate a regenerative torque that substitutes for the deceleration torque by the auxiliary brake.

  When the exhaust brake is used as the auxiliary brake, when the engine 11 is running at a low speed, there is an engine stall restriction. Therefore, when the engine speed Ne is equal to or lower than the preset first operation stop speed Ne1. It is necessary to stop the operation of the exhaust brake. That is, the auxiliary brake composed of these brakes is inactivated when the engine is running at a low speed during deceleration.

  Even when a compression release brake is used as the auxiliary brake, when the engine 11 is running at a low speed, the hydraulic pressure of the hydraulic oil as a power source for driving the exhaust valve cannot be secured, so the engine speed Ne is set in advance. When the rotation speed is less than the second operation stop speed Ne2, it is necessary to stop the operation of the compression release brake. Normally, the second operation stop rotational speed Ne2 for the compression release brake is larger than the first operation stop rotational speed Ne1 for the exhaust brake.

  When this auxiliary brake is composed only of an exhaust brake, when the engine speed Ne decreases during deceleration and becomes equal to or less than the first operation stop speed Ne1, the operation of the exhaust brake is stopped, that is, the exhaust brake. The brake valve 17 is changed from closed to open, and the stop of the operation is detected by the brake operation stop detection means 41a, and the same magnitude as the braking torque by the exhaust brake operation is matched with the timing to stop the operation of the exhaust brake. The regenerative torque is generated by the motor generator 21, the regenerative brake operation is started, and the regenerative brake is performed until the deceleration is completed.

  In some cases, the operation of the exhaust brake is not stopped only at the engine speed Ne. In this case, the exhaust brake valve 17 or a signal for supporting the stop of the exhaust brake is used instead of the engine speed Ne. It is possible to detect the stoppage of the exhaust brake by a signal or the like for opening the valve.

  This control will be described with reference to the control flow of FIG. 2. When the driver decelerates by stepping on the foot brake, the control flow of FIG. 2 is called from the advanced control flow, and the engine speed Ne is input in step S12. In step S12, it is determined whether or not the engine speed Ne is equal to or lower than the first operation stop speed Ne1, and if the engine speed Ne is equal to or lower than the first operation stop speed Ne1, the exhaust is determined. While stopping the operation of the brake, the motor generator 21 generates regenerative torque. Thereafter, when the deceleration is completed in the determination in step S14, the regeneration control by the motor generator 21 is stopped in step S15, and the process returns to the advanced control flow.

  When the auxiliary brake is composed only of the compression release brake, when the engine speed Ne decreases during deceleration and becomes equal to or less than the second operation stop speed Ne2, the operation of the compression release brake is stopped. The operation stop is detected by the brake operation stop detection means 41a, and the regenerative torque having the same magnitude as the braking torque by the compression release brake operation is detected by the motor generator 21 in accordance with the timing at which the operation of the compression release brake is stopped. Generates and starts regenerative brake operation, and performs regenerative braking until deceleration is completed.

  Further, when the auxiliary brake is configured by both the exhaust brake and the compression release brake, when the engine speed Ne decreases during deceleration and becomes less than the second operation stop speed Ne2, the operation of the compression release brake is stopped. While stopping, this is detected by the brake operation stop detection means 41a, and the regenerative torque having the same magnitude as the braking torque by the compression release brake operation is generated by the motor generator 21 to start the operation of the regenerative brake.

  Further, when the engine speed Ne decreases and becomes equal to or less than the first operation stop speed Ne1, the operation of the exhaust brake is stopped, that is, the exhaust brake valve 17 is opened from the closed valve, In addition to the regenerative torque generated by the motor generator 21, the regenerative torque detected by the brake operation stop detection means 41a and the same magnitude as the braking torque generated by the exhaust brake operation is applied, and the regenerative brake is operated. Regenerative braking is performed until completion.

  This control will be described with reference to the control flow of FIG. 3. When the driver decelerates by stepping on the foot brake, the control flow of FIG. 3 is called from the advanced control flow, and the engine speed Ne is input in step S22. In step S22, it is determined whether or not the engine speed Ne is equal to or lower than the second operation stop speed Ne2. If the engine speed Ne is equal to or lower than the second operation stop speed Ne2, the compression is performed. After stopping the operation of the release brake, the motor generator 21 generates a regenerative torque corresponding to the braking torque due to the compression release immediately before the operation stop, and then inputs the engine speed Ne in step S24, and in step S25. Then, it is determined whether or not the engine speed Ne is equal to or lower than the first operation stop speed Ne1, and the engine speed Ne is set to the first operation stop speed Ne1. If it becomes lower, it stops the operation of the exhaust brake, increasing the regenerative torque generated by the motor generator 21 by adding the braking torque caused by exhaust brake immediately before deactivation. Thereafter, when the deceleration is completed in the determination in step S27, the regeneration control by the motor generator 21 is stopped in step S28, and the process returns to the advanced control flow.

  In the control of the control flow of FIG. 3, the first operation stop rotational speed Ne1 is assumed to be larger than the second operation stop rotational speed Ne2, but if it is smaller, the engine speed Ne decreases and the first operation stop rotational speed is reduced. When Ne1 or less, the operation of the exhaust brake is stopped, and this is detected by the brake operation stop detecting means 41a, and the motor generator 21 generates a regenerative torque having the same magnitude as the braking torque by the exhaust brake operation. Start regenerative braking.

  Further, when the engine speed Ne decreases and becomes equal to or lower than the second operation stop speed Ne2, the operation of the compression release brake is stopped, and this operation stop is detected by the brake operation stop detection means 41a. A regenerative torque having the same magnitude as the braking torque generated by the release brake operation is added to the regenerative torque generated by the motor generator 21, the regenerative brake is operated, and the regenerative brake is performed until the deceleration is completed.

  Note that the braking torque immediately before the operation of the compression release brake and the exhaust brake is stopped can be calculated or estimated in advance by data obtained through experiments or the like, and calculation at the time of control. Therefore, the motor generator 21 is easily controlled to Regenerative torque of the same magnitude can be generated.

  According to the hybrid vehicle 1 and the hybrid vehicle control method configured as described above, when the braking force due to the stoppage of the operation of the exhaust brake or the compression release brake disappears at the time of deceleration, the lost torque of the braking force is reduced by the motor generator. Since the generated regenerative torque is substituted, a reduction in braking force can be avoided.

  Therefore, even after the auxiliary brake is deactivated, the deceleration does not loosen suddenly and the driver does not feel that the brake has been released. Can be reduced. In addition, since the lining of the drum brake and the wear of the pad due to the additional depression of the main brake can be prevented, the life of these brake parts can be extended.

1 Vehicle (Hybrid vehicle: HEV)
2 Hybrid system 11 engine (internal combustion engine)
12 Exhaust passage 13 Turbocharger 14 Exhaust gas purification device 15 Crankshaft 16 CVT (continuously variable transmission mechanism)
17 Exhaust brake 20 Electric power system 21 Motor generator (M / G)
30 Power transmission system 40 Overall control device 41 Hybrid system control device 41a Brake operation stop detection means Ne Engine speed Ne1 First operation stop speed Ne2 Second operation stop speed

Claims (8)

In a hybrid vehicle that is equipped with both an internal combustion engine and a motor generator and is inactivated when the auxiliary brake is at low engine speed during deceleration,
Control for hybrid system comprising brake operation stop detection means for detecting operation stop of the auxiliary brake during deceleration, and performing regenerative operation of the motor generator when the operation stop of the auxiliary brake is detected during deceleration A hybrid vehicle comprising the device.   The hybrid system control device is configured to perform control to generate a regenerative torque having the same magnitude as the braking torque of the auxiliary brake when detecting the stop of the operation of the auxiliary brake. The hybrid vehicle according to 1.   The brake operation stop detection means sets a lower limit value at which the auxiliary brake can be operated as an operation stop rotational speed, and when the engine speed becomes equal to or lower than the operation stop rotational speed, the operation stop of the auxiliary brake is stopped. The hybrid vehicle according to claim 1, wherein the vehicle is detected.   The hybrid vehicle according to claim 1, wherein the auxiliary brake includes at least one of an exhaust brake and a compression release brake. In a control method for a hybrid vehicle that is equipped with both an internal combustion engine and a motor generator and is inoperative when the auxiliary brake is at low engine speed during deceleration,
Control of a hybrid vehicle, wherein when the operation stop of the auxiliary brake is detected during deceleration, the motor generator is regenerated to generate regenerative torque that substitutes for deceleration torque by the auxiliary brake. Method.   6. The control method for a hybrid vehicle according to claim 5, wherein when the operation stop of the auxiliary brake is detected, control is performed to generate a regenerative torque having the same magnitude as the braking torque of the auxiliary brake.   7. The operation stop of the auxiliary brake is detected when the engine rotation speed is equal to or lower than the operation stop rotation speed that is a lower limit value at which the auxiliary brake can be operated. The hybrid vehicle control method described.   The hybrid vehicle control method according to claim 5, wherein the auxiliary brake includes at least one of an exhaust brake and a compression release brake.

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