JP2953642B2 - Vehicle regenerative braking device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an apparatus for recovering brake energy in a vehicle, which recovers the deceleration energy of the vehicle and uses the energy for starting and acceleration.

[0002]

2. Description of the Related Art Among kinetic energy lost when a vehicle is decelerated, energy which is mainly dissipated as heat is recovered as hydraulic pressure, which is stored in an accumulator and used as energy for starting and accelerating the vehicle. The regenerative braking device is disclosed in JP-A-62-15128, JP-A-62-37215, JP-A-62-39327, JP-A-2-117434, and JP-A-2-11743.
No. 7 is disclosed in each publication.

[0003] Such a vehicle regenerative braking device is shown in FIG.
As shown in FIG.
a, a rear drive shaft 4 is attached to the differential gear 4 that rotationally drives the wheels 3 via the differential gear 4.
b, an electromagnetic clutch 5 is provided, and a pump motor 6 is connected via the electromagnetic clutch 5.

Then, an accelerator opening signal, a select lever position signal of the select lever 8, a rotation speed signal of the engine 2 and a shift position signal of the transmission 1 generated by the depression of the accelerator pedal 7 are inputted, and based on these signals, The output of the engine 2 is controlled by a first control device A for an engine and a transmission that outputs a rack control signal to the engine 2.

During normal running of the vehicle, the electromagnetic clutch 5 is disengaged by the second control device B for controlling the pump motor so that the rotation of the engine 2 is not transmitted to the pump motor 6.

When the brake pedal 9 is depressed, the electromagnetic clutch 5 is connected by a signal from the control device B, and the pump motor 6 is driven by the rear drive shaft 12b to pump oil in the oil tank 10 to the accumulator 11 by pressure. Then, the oil is accumulated in the accumulator 11.

When the accelerator pedal 7 is depressed to start or accelerate the vehicle, a hybrid operation permission control signal is transmitted from the control device A to the control device B, the electromagnetic clutch 5 is connected, and the accumulator 11 is charged. Drives the wheels 3 using the pump motor 6 as a motor.

Accordingly, the rotation of the pump motor 6 is transmitted to the differential gear 4 via the rear drive shaft 12 to start and accelerate the vehicle. As this pump motor 6,
A pump motor 6 capable of changing the oblique axis angle depending on the state of the brake and the degree of the starting acceleration is generally employed.

The oblique-axis pump motor 6 shown in FIG. 9 has a suction port 6a and a discharge port 6b, and a shaft 6d engaged with an output shaft 6c is inserted into a center hole of a cylinder block 6f. The engaged output shaft 6c and the shaft 6d have a predetermined oblique axis angle (the angle θ between the output shaft 6c and the shaft 6d), and the control piston 6A is engaged with the opposite side of the shaft 6d via a port plate 6h. I agree.

A plurality of cylinders 6g are provided in the circumference of the cylinder block 6f. One end of the cylinder 6g has a piston 6g engaged with the output shaft 6c.
e is slidably inserted, and the opposite side communicates with the suction port 6a or the discharge port 6b via the port plate 6h.

The control piston 6A includes a control solenoid valve 6B
Is pushed by hydraulic oil supplied from the control pilot pipe to the lower portion of the control piston 6A in proportion to the control current supplied to the control piston 6A, so that the position changes in the vertical direction in the figure.

Therefore, an assembly including the cylinder block 6f, the piston 6e, the shaft 6d, and the port plate 6h is centered on the spherical groove of the shaft 6d engaged with the output shaft 6c, and is moved obliquely with the vertical movement of the control piston 6A. The angle changes.

FIG. 9 shows a state in which the maximum control current is applied to the tilt angle control solenoid valve 6B. Since the tilt angle becomes maximum, the discharge amount per rotation of the output shaft 6c is maximum. It has become.

When the control current of the tilt angle control solenoid valve 6B is zero, the oblique axis angle θ becomes zero and the discharge amount becomes zero as shown by the dotted line. The control device A and the control device B in the above-described vehicle regenerative braking device operate according to the flowchart of FIG.

When the process is started in step S1, the start of the engine 2 is confirmed in step S2, and in the case of start, the control power of the pump motor 6 is checked in step S3.

If it is ON, it is determined in step S4 that the test mode switch is OFF. If it is OFF, it is confirmed in step S5 that the selector position of the select lever 8 is at a position corresponding to forward movement, and YES is determined. In this case, it is confirmed in step S6 that the vehicle is traveling at the speed V0 or less.

In the case of YES, it is confirmed in step S7 that the brake pedal 9 is depressed, and in step S8, the electromagnetic clutch 5 is operated so that the vehicle can apply both the engine brake and the pump motor 6. The control device B outputs so as to be in a hybrid braking mode such as connection.

If the result of step S2 is NO, the engine 2 is not started, and the circulation to step S2 is repeated until the engine 2 is started. If the control power supply to the pump motor 6 is turned off in step S3, Is the step S9
The control device B outputs to perform traveling in the normal traveling mode.

In step S4, the test mode switch is set to O
In the case of the FF, the process proceeds to step S10 to continue the test operation in the test mode. If the select lever 8 is at the neutral position other than the forward position and the retreat position in step S5, the process proceeds to step S9 to continue the normal mode traveling.

If the vehicle speed is equal to or higher than V0 in step S6, the control device B outputs an output such as disengaging the electromagnetic clutch 4 in step S11 so that the traveling in the normal mode is performed.

If it is determined in step S7 that the brake pedal 9 has not been depressed, the process proceeds to step S12. If the accelerator pedal 7 has been depressed, the process proceeds to step S9 and the vehicle travels in the normal mode in the same manner as described above.

However, if the accelerator pedal is depressed in step S12, the controller B uses the pump motor 6 as a motor in step S13.
The electromagnetic clutch 5 is connected for the hybrid running mode in which the vehicle starts and accelerates.

[0023]

In such a conventional vehicle regenerative braking device, when starting and accelerating the vehicle, the torque required for starting and accelerating is determined by the accelerator opening and the shift lever position of the transmission. And the output of the pump motor based on the oblique axis angle and the engine output are controlled.

Therefore, it is necessary for the control device to always perform a numerical calculation required for traveling in the hybrid traveling mode.
Therefore, there is a disadvantage that the control accompanying this becomes complicated. In the present invention, in order to solve the above-mentioned problem in the conventional vehicle regenerative braking device, the engine control and the pump motor control during hybrid running while adding the engine output and the motor output of the pump motor by accumulating pressure are performed. It is intended to simplify control.

[0025]

SUMMARY OF THE INVENTION In order to achieve the above-mentioned object, the present invention has a construction in which a variable displacement pump motor is connected via a clutch to a rear drive shaft connected to a differential gear of a vehicle. Then, an oil tank and an accumulator that accumulates oil are connected to the pump motor, the clutch is disengaged during normal running, and the clutch is connected during vehicle braking, and the oil in the oil tank is used as a pump by using the pump motor as a pump. In a vehicle regenerative braking device equipped with a control device that drives the vehicle with the oil storage pressure of an accumulator and the driving force of an engine using a pump motor as a motor when the vehicle starts and accelerates, the pressure is stored in the accumulator. Provide a pressure accumulation sensor that detects the amount and detect the shift position in the vehicle transmission A shift position sensor is provided, based on signals from the pressure accumulation sensor and the shift position sensor, a variable displacement map for keeping the output of the pump motor according to the accumulated pressure amount of the accumulator in advance, and an accelerator opening based on the shift position of the transmission. Means for performing pump motor control and engine control based on the fuel injection amount map.

[0026]

According to the above configuration, during hybrid traveling in which the vehicle travels by adding the stored energy in addition to the engine output, the variable displacement (oblique axis angle) of the pump motor is adjusted according to the accumulated pressure in the accumulator. The motor output (drive torque) of the pump motor can be kept constant.

Therefore, during hybrid traveling, the driving force of the pump motor is constant, so that the engine control may be performed by controlling the engine output excluding the driving force of the pump motor by limiting the injection amount set for each shift position. As a result, the control is simplified, and the same operating performance as that of running only with the engine can be obtained.

[0028]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to FIGS. In this embodiment, the oblique-axis pump motor 6 shown in FIG. 9 is employed as a variable displacement pump motor.
As described above, this is an assembly including the cylinder block 6f, the piston 6e, the shaft 6d, and the port plate 6h. When the tilt angle of the pump motor 6 is maximum, the discharge amount per rotation of the output shaft 6c is maximum, and when the oblique axis angle θ is zero as indicated by the dotted line, , The discharge amount also becomes zero.

In the block diagram of FIG. 1, a ROM (read only memory) is provided in the control device B of FIG. 8 shown as a conventional example. In this ROM, as shown in FIGS. 3 and 4, by adjusting the oblique axis angle of the pump motor 6 set according to the accumulated pressure of the accumulator 11, the oblique axis angle pump is controlled so that the driving torque becomes constant. A map of the oblique axis angle θ of the motor 6 is stored.

Since the driving force of the pump motor 6 is constant, the ROM excludes the engine output from the ROM and determines the fuel supply amount of the fuel injection determined by the opening degree of the accelerator pedal 7 at each shift position of the transmission 1. The map (FIG. 5) is input and stored as in FIG.

As shown in FIG. 8, the central processing unit CPU provided in the control device B receives the position of the select lever 8 from the control device A, the opening degree of the accelerator pedal 7, the engine speed, and the accumulator. 11 is input via the input interface (input I / F),
The oblique axis angle change command and the fuel injection control (full rack position limit command) are output to the pump motor 6 via an output interface (output I / F).

The input interface includes a signal from a shift position sensor provided in the transmission 1, a signal from an accelerator opening sensor provided in the accelerator pedal 7, and a signal from an engine rotation sensor provided in the engine 2. And the signal from the accumulator sensor provided in the accumulator 11 are input.

The central processing unit CPU operates in accordance with the flow chart of FIG. 2. FIG. 2 shows the operation of the control unit B of the vehicle regenerative braking device when the hybrid driving mode is set to the hybrid running mode in step S13 in FIG. Is shown.

In step S13, when the accumulated pressure of the accumulator 11 is equal to or lower than the predetermined pressure VH0 in step S14, the routine proceeds to step S9 of the normal mode traveling as in the conventional case, and the normal mode is executed. Output for running on

However, when the pressure is equal to or higher than the pressure VH0, in step S15, an output is provided to the pump motor 6 so that the angle becomes an oblique axis according to the oblique axis angle map of the pump motor 6 accompanying the change in the pressure.

Then, in step S16, according to the position of the select lever 8, the accelerator opening, and the engine speed, the output is output to the full rack position based on the stored full rack reduction map for each shift position, and the rotation of the engine 2 is performed. After controlling the speed, the process returns to step S2 in step S17.

Therefore, the output of the pump motor 6 is always kept constant irrespective of the magnitude of the accumulated pressure of the accumulator 11,
The driving force and running resistance required by the vehicle to obtain the vehicle speed at that time are as shown by a dotted line in FIG. 6 depending on the position of the select lever 8, and the output of the pump motor 6 at that time is represented by a horizontal straight line in FIG. The total driving force is shown by the solid line in FIG. 7, and the full rack reduction map of the engine 2 at that time is as shown in FIG.

[0038]

As described above, according to the present invention, the output of the pump motor is kept constant during the hybrid running in which the vehicle is driven by both the pump motor and the engine, so that the present invention can be applied to a conventional case where both are controlled. In addition, there is no need to perform complicated calculations and controls, and it is sufficient to control the engine according to the position of the select lever.

Accordingly, there is no need for the control unit to perform complicated calculations during hybrid traveling, and control based on the calculation results can be limited to only the fuel injection amount to the engine, which has the advantage that the vehicle regenerative braking device can be simplified. It is.

[Brief description of the drawings]

FIG. 1 is a block diagram of a circuit of the present invention.

FIG. 2 is a flowchart of the same.

FIG. 3 is a diagram illustrating a relationship between a pressure accumulation amount and a driving force based on pressure accumulation energy.

FIG. 4 is a diagram illustrating a relationship between a pressure accumulation amount and an oblique axis angle.

FIG. 5 is a diagram illustrating a relationship between an engine speed and an injection amount rack position.

FIG. 6 is a diagram showing a relationship between a vehicle speed, a driving force, and running resistance depending on a shift lever position during hybrid running according to the present invention.

FIG. 7 is a full rack reduction map at that time.

FIG. 8 is a configuration diagram of a conventional vehicle regenerative braking device.

FIG. 9A is a cross-sectional view of the above-described oblique-axis angle pump motor,
(B) is a perspective view from the arrow A direction.

FIG. 10 is a flowchart based on FIG.

[Explanation of symbols]

 A, B control device 2 engine 3 wheels 4 differential gear 5 electromagnetic clutch 6 pump motor 7 accelerator pedal 8 select lever 9 brake pedal 10 oil tank 11 accumulator 12a drive shaft 12b rear drive shaft

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁶ , DB name) B60K 25/00 B60T 1/10

Claims (1)

(57) [Claims] 1. A variable displacement pump motor is connected via a clutch to a rear drive shaft connected to a differential gear of a vehicle, and an oil tank and an accumulator for accumulating oil are connected to the pump motor. During normal driving, the clutch is disengaged, and when the vehicle is braked, the clutch is connected and the pump motor is used as a pump to pump oil in the oil tank to the accumulator to accumulate pressure,
In a vehicle regenerative braking device including a control device that drives a vehicle with an accumulator oil pressure and an engine driving force using a pump motor as a motor when the vehicle starts and accelerates, a pressure accumulation sensor that detects a pressure accumulation amount in the accumulator. And a shift position sensor for detecting a shift position in the transmission of the vehicle, and a variable displacement for making the output of the pump motor constant according to the accumulated pressure amount of the accumulator in advance based on the signals from the pressure accumulation sensor and the shift position sensor. A vehicle regenerative braking device, characterized in that the control device includes means for performing pump motor control and engine control using a map and a fuel injection amount map according to an accelerator opening based on a shift position of a transmission.