JPH0723065B2 - Vehicle brake energy regeneration device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a vehicle brake energy regeneration device that recovers deceleration energy of a vehicle and uses it as start / acceleration energy.

[Conventional technology]

Of the kinetic energy that is lost when the vehicle decelerates, the amount that is dissipated (brake, engine) mainly as heat is collected as operating hydraulic pressure and accumulated in the accumulator, and this accumulated energy is used as the starting energy and acceleration energy of the vehicle. A deceleration energy recovery device for vehicles equipped with a PTO (Power-take-off) output device or an axle equipped with a transfer has been known for a long time. The oldest was CJ Lawrence in England in 1976 when a British Leyland bus was used. Since it was announced that it is under development, various researches and developments have been conducted in Europe and the United States, and recently, JP-A-62-15128, JP-A-62-37215 and It is disclosed in Japanese Laid-Open Patent Publication No. 62-39327.

Each of the latter devices is a transmission having a multi-stage gear train mechanism that shifts and transmits the rotation of a counter shaft driven via an engine clutch, a main shaft connected to a wheel drive system, and the counter shaft to the main shaft. , T / M), the counter shaft PTO gear mounted on the counter shaft so that it can be connected and disconnected via the counter shaft PTO gear synchronizer, and this PTO gear is gear-coupled to the main shaft PTO main shaft PTO.
A multi-stage transmission type PTO device having a main shaft PTO gear that is detachably mounted via a gear synchronizer and a PTO output shaft that is driven via a drive gear that is connected to this main shaft PTO gear. Connected pump / motor, hydraulic circuit that connects the accumulator and oil tank via this pump / motor, electromagnetic clutch that enables and disconnects this hydraulic circuit and PTO shaft, and the pump / motor that controls the electromagnetic clutch. The accumulator and pump / motor connected by the high-pressure oil circuit are made to function as either one of the pump and the motor depending on the operating condition of the vehicle (that is, they function as a pump at the time of deceleration, and the rotational force of the wheels causes the PTO device to operate. Kinetic energy lost mainly as brake and engine heat by accumulating hydraulic oil in the accumulator (below Generates a rotational force by the hydraulic fluid when starting / acceleration which has been accumulated in the accumulator is recovered is referred to as brake energy) PTO
A control unit that functions as a motor that rotationally drives the wheels through the device) is configured as a main part.

Such control means of the deceleration energy recovery device controls the capacity of the variable displacement motor (the tilt angle of the swash plate or the swash shaft) according to the amount of depression of the accelerator pedal when the vehicle starts and when the hydraulic pressure in the accumulator is sufficient. Controlling and connecting an electromagnetic clutch to start by hydraulic pressure by a hydraulic circuit, and when the vehicle speed set corresponding to the gear selected by the driver is exceeded during that time, the engine clutch is connected to drive the engine. At the same time as starting the PTO device, control the gear shift and turn off the countershaft synchronizer that was on and turn on the main shaft synchronizer.Furthermore, when the accelerator pedal depression amount is large at that time, the engine drives the hydraulic pressure according to the depression amount. Control the force.

During braking, the electromagnetic clutch is connected and the tilt angle control signal (pump displacement control signal) according to the depression of the brake pedal is applied to the pump / motor to perform the pump operation, and at the same time, the control to disengage the engine clutch is performed. .

In this case, the control means collects the portion of the braking energy consumed by the engine brake based on the control program, and disconnects the engine from the drive system of the wheels during traveling by the motor. In addition to the control so that the motor and the engine are used together, or when the vehicle is started / accelerated only by the engine, the control is performed so as to be “contact”.

[Problems to be Solved by the Invention]

In the case of such a conventional technique, even when the driver stops the vehicle and turns off the key switch, the actuator relay that finally turns off the power of the entire system is still energized unless the power off signal is simultaneously generated from the CPU. It is generally in a state.

That is, as shown in FIG. 3, in the actuator relay 40 used in an automobile or the like, when the key switch 41 is turned on, an “H” level output is given to the NOR gate 43, so
Since the output of the OR gate 43 becomes “L” level regardless of the output of the MPU 42, the transistor 44 is turned on, the relay coil 40a is energized, and the contact 40b is connected, so that the entire vehicle is supplied with 24V. Give power.

On the other hand, when the key switch 41 is turned off, the output of the key switch 41 becomes "L" level. In this state, the MPU42
Since the output of is kept at "H" level, transistor 44 remains on, and actuator relay 40 therefore remains energized. This is because it is necessary to supply power to the vehicle for a certain period of time after turning off the key switch 41.

Therefore, if the driver steps on the accelerator pedal within a certain time from when the key switch 41 is turned off until the output of the MPU 42 becomes "L" level, the hydraulic circuit will work and cause an unexpected accident. There was a problem that became.

Therefore, it is an object of the present invention to realize a brake energy regeneration system for a vehicle that can prevent the hydraulic circuit from working when the key switch is turned off.

[Means for Solving the Problems]

In order to achieve the above object, the vehicle brake energy regeneration device according to the present invention accumulates hydraulic pressure in the high pressure accumulator via the pump / motor and the circuit valve connected to the power branch mechanism from the low pressure accumulator during deceleration energy recovery. When regenerating the stored energy, a hydraulic circuit for hydraulically discharging the high-pressure accumulator to the low-pressure accumulator via the circuit valve and the pump / motor, an actuator relay for turning on / off the power of the entire device, and a key switch are provided. When turned off, the tilt angle of the pump / motor is set to zero, the circuit valve is shut off, and then the power branch mechanism is disconnected from the hydraulic circuit, and then the actuator relay is turned off to turn off the power. And a control means.

[Action]

In the present invention, when the driver turns off the key switch, the control means detects this and prevents the hydraulic circuit from operating first. Therefore, the tilt angle of the pump / motor in the hydraulic circuit is set to zero, The circuit valve in the hydraulic circuit is closed, and the power branch mechanism between the electromagnetic clutch and any of the normal drive systems such as the PTO device and axle is disconnected from the hydraulic circuit.

In this way, a signal for turning off the actuator relay is generated after performing any control, and the power of the entire vehicle is turned off.

As a result, even if the key switch is turned off when the vehicle is stopped or running, in order to ensure safety, it is controlled to turn off the power after returning the hydraulic system to a safe state, so the actuator relay turns off. Even before the power is turned off, that is, when the accelerator pedal is depressed, the danger of hydraulic pressure starting is eliminated.

〔Example〕

FIG. 1 is a configuration diagram of an embodiment of a vehicle brake energy regeneration device to which the present invention is applied, and 1 is an axle 20
A PTO device 2 that takes out the driving force of the wheels 21 as a hydraulic braking force via the electromagnetic clutch 4 that connects and disconnects the driving force transmission between the PTO device 1 and the pump / motor 3 that executes the pump operation during braking. Is a circuit switching valve as a circuit valve, 5
Is a high pressure accumulator, 6 is a low pressure accumulator forming a hydraulic circuit together with the pump / motor 3, the circuit switching valve 4 and the high pressure accumulator 5, and 11 is a tilt angle sensor of the pump / motor 3. Pressure sensors 12 and 13 are attached between the circuit switching valve 6 and the pump / motor 3, and between the pump motor 3 and the circuit switching valve 4, respectively.
The hydraulic pressure value of each part is sent to the control unit (C / U) 15 as a control means. The control unit 15 controls the tilt angle (capacity) of the pump / motor 3,
Switching / closing control of the circuit switching valve 4 and connection / disconnection control of the electromagnetic clutch 2 are performed. Reference numeral 22 is a transmission (T / M) that includes the PTO device 1 and is connected to an engine (not shown) by an automatically controlled engine clutch 23. By doing so, the engine can be disconnected during energy recovery / regeneration.

The operation of the brake energy regenerator of such an embodiment will be described below with reference to the flowchart of FIG.

First, the control unit 15 determines the state of the key switch 41 (step S1). As a result of this determination, when the key switch 41 is turned on, hydraulic energy control and normal brake control are executed (step S6).

Here, these controls will be briefly described.

Energy recovery mode Now, when an energy recovery mode command is given to the control unit 15 by the driver depressing a brake pedal (not shown), for example, the control unit
Reference numeral 15 controls the circuit clutch 4 after switching the electromagnetic clutch 2 to the connected state, and controls the tilt angle of the pump / motor 3 in accordance with the amount of depression of the brake pedal.

As a result, the oil in the low pressure accumulator 6 is accumulated in the high pressure accumulator 5 through the route of the circuit switching valve 4 → the pump / motor 3 → the circuit switching valve 4 → the high pressure accumulator 5.

Energy recovery mode As described above, the hydraulic energy stored in the high-pressure accumulator 5 is given to the control unit 15 by an energy recovery mode command when the driver depresses an accelerator pedal (not shown), for example. Puts the electromagnetic clutch 2 into the connected state,
The circuit switching valve 4 is switched and controlled, and the tilt angle of the pump / motor 3 is controlled according to the amount of depression of the accelerator pedal.

In the above hydraulic circuit operation, the engine clutch 22 is normally automatically disengaged by a control signal from the control unit 15. In a normal automatic transmission vehicle that does not use an automatic clutch, the gear position is controlled to be neutral.

Normal brake control mode In addition to this, there is a mode in which no hydraulic circuit is used. In this case, the tilt angle of the pump / motor 3 is set to 0 (capacity 0).
Therefore, even if pressure is applied to the pump / motor 3, the pump / motor 3 is prevented from rotating, and the circuit switching valve 4
Is completely turned off (valve closed state) to disconnect the hydraulic circuit, then the electromagnetic clutch 2 is disengaged, the pump / motor 3 is disconnected from the PTO device 1 and the wheel 21, and the hydraulic braking force is completely applied from the wheel 21. Shut off.

Returning to step S1 in FIG. 2, when the key switch 41 is turned off and turned off, the following control for stopping all controls is performed.

First, the tilt angle of the pump / motor 3 is set to "0" and the displacement is set to "0", that is, the pump / motor output is set to "0" (step 2).

In this case, if the tilt angle of the pump / motor 3 is not exactly "0", an output will be generated.
It is preferable that the tilt angle “0” is realized by fetching the actual tilt angle signal into the control unit 15 by 11 and applying feedback control.

Next, the valve position of the circuit switching valve 4 is controlled to the valve closed state as shown in the drawing in which all ports are disconnected (step S3).

Also in this case, unless the circuit switching valve 4 is actually closed, the hydraulic circuit from the high pressure accumulator 5 to the low pressure accumulator 6 via the pump / motor 3 may work.

Therefore, it is preferable to confirm that the circuit switching valve 4 is completely controlled.

That is, after the control unit 15 controls the circuit switching valve 4 to close it, the absolute value of the pressure difference between the pressure sensors 12 and 13 provided on the pump / motor side of the circuit switching valve 4 is controlled. │P ₁₂ −P ₁₃ │ is calculated and this absolute value
It suffices to determine whether it is higher or lower than the constant conduit resistance pressure P _M in the motor 3.

When | P ₁₂ −P ₁₃ | is substantially equal to the line resistance pressure P _M, it means that the hydraulic pressure difference across the pump / motor 2 is equal to the line resistance pressure of the pump / motor 2 itself. And
This means that the circuit switching valve 4 has been closed.

In this way, the hydraulic circuit is made inoperative by controlling the circuit switching valve 4 and the pump / motor 3 that form the hydraulic circuit, and then the electromagnetic clutch 2 is further controlled to be disengaged (step S4). The control of the electromagnetic clutch 2 may be open loop control.

As a result, all control of the hydraulic system has been stopped, and the vehicle will not start even if the driver depresses the accelerator pedal.

After that, as shown in FIG. 3, the control unit 15 causes the internal arithmetic unit 42 to turn off the transistor 44 via the NOR gate 43 so that the actuator relay 40 is activated.
An output signal for turning off the coil 40a is generated, and the coil 40a of the actuator relay 40 is deenergized by this, so that the regenerative system power is turned off by the relay contact 40b.

Although the circuit switching valve has been described as the circuit valve in the above embodiment, a simple circuit shut-off valve that does not need to switch the hydraulic circuit depending on the type of pump / motor can be used.

Also, if at least one of the control of the tilt angle of the pump / motor, the closing control of the circuit switching valve, and the disconnection control of the electromagnetic clutch is performed, the operation such as the hydraulic start after the key switch is turned off is prevented. You can

〔The invention's effect〕

As described above, in the vehicle brake energy regeneration device according to the present invention, when the key switch is turned off, the hydraulic circuit system is made inoperative, the power branch mechanism is disconnected, and then the actuator relay is turned off. Even if the accelerator pedal is accidentally depressed, the danger of the vehicle starting due to the hydraulic circuit is eliminated, and the vehicle can be kept in a safe state.

[Brief description of drawings]

FIG. 1 is a diagram showing a configuration of an embodiment to which a vehicle brake energy regeneration device according to the present invention is applied, FIG. 2 is a flow chart diagram showing an operation when all controls are stopped according to the present invention, and FIG. FIG. 3 is a diagram showing a control circuit of an actuator relay that is generally well known. In FIG. 1, 1 is a PTO device, 2 is an electromagnetic clutch, and 3
Is a pump / motor, 4 is a circuit switching valve, 5 is a high-pressure accumulator, 6 is a low-pressure accumulator, 11 is a tilt angle sensor,
12 and 13 are hydraulic pressure sensors, 15 is a control unit (C /
U), 40 is an actuator relay, 41 is a key switch, 4
Reference numeral 2 denotes a computing unit (MPU) inside the control unit 15, respectively. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. When the deceleration energy is recovered, the low pressure accumulator is hydraulically accumulated in the high pressure accumulator through a pump / motor and a circuit valve connected to the power branch mechanism, and when the accumulated energy is regenerated, the high pressure accumulator is used to regenerate the circuit valve. And a hydraulic circuit for releasing hydraulic pressure to the low-pressure accumulator via the pump / motor, an actuator relay for turning on / off the power of the entire device, and a tilt angle of the pump / motor to zero when the key switch is turned off. And a control means for shutting off the circuit valve and then disconnecting the power branching mechanism from the hydraulic circuit and then turning off the actuator relay to turn off the power supply. Energy regeneration device.