JP2580742B2 - Vehicle brake energy regeneration device - Google Patents

Description

Description: BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a vehicle brake energy regenerating device that collects 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 mainly dissipated (brake, engine) as heat is recovered as operating hydraulic pressure and accumulated in the accumulator, and the accumulated energy is used as the starting energy and acceleration energy of the vehicle. A deceleration energy recovery device for a vehicle equipped with a power-tak-off (PTO) output device or an axle with a transfer has been known, and in 1976 the British CJ Lawrence Company of the United Kingdom issued a British Leyland bus. It has been announced that it is under development, and various researches and developments have been made in Europe and the United States. Recently, Japanese Patent Application Laid-Open Nos. 62-15128 and 62-372
No. 15, JP-A-62-39327, and the like.

Each of the latter devices has a transmission (hereinafter referred to as a transmission) having a counter shaft driven via an engine clutch, a main shaft connected to a wheel drive system, and a multi-stage gear train mechanism that transmits the rotation of the counter shaft to the main shaft at a variable speed. , T / M), a countershaft PTO gear mounted on the countershaft via a countershaft PTO gear synchronizer and this PTO
The main shaft to the gear-coupled main shaft of the gear
Multi-stage PTO device having a main shaft PTO gear detachably mounted via a PTO gear synchronizer and a PTO output shaft driven via a drive gear coupled to the main shaft PTO gear, PTO shaft Pump motor connected to the accumulator and oil tank via this pump motor, this hydraulic circuit and PT
An electromagnetic clutch capable of disconnecting from the O-axis, and an accumulator connected to the pump / motor via a high-pressure oil circuit by controlling the electromagnetic clutch, and the pump / motor depending on the operating state of the vehicle, either a pump or a motor. It functions as one (that is, it functions as a pump at the time of deceleration and stores hydraulic oil in an accumulator via a PTO device by the rotational force of the wheels, so that kinetic energy mainly lost as heat of the brake and engine (hereinafter referred to as brake energy) ) Is collected, and at the time of start / acceleration, hydraulic oil is accumulated in the accumulator to generate rotational force and PT
The control means (which functions as a motor for rotating and driving the wheels via the O device) is configured as a main part.

The control means of such a deceleration energy recovery device, when starting, when the hydraulic pressure in the accumulator is sufficient, changes the capacity of the variable displacement motor (tilt angle of the swash plate or the swash axis) according to the amount of depression of the accelerator pedal. Control and connect the electromagnetic clutch to start by hydraulic pressure using the hydraulic circuit. During this time, when the vehicle speed exceeds the speed set according to the gear selected by the driver, connect the engine clutch to drive the engine. At the same time, the shift control of the PTO device is performed and the counter shaft synchronizer that was on is turned off, the main shaft synchronizer is turned on, and furthermore, only when the accelerator pedal depression amount at that time is large, the oil pressure according to the depression amount is applied. Do.

At the time of braking, the electromagnetic clutch is connected and a tilt angle control signal (pump displacement control signal) corresponding to the depression of the brake pedal is given to the pump / motor to perform the pump operation.
At the same time, control for disengaging the clutch of the engine is performed.

In this case, the control means, based on the control program,
In order to recover the amount consumed by the engine brake in the brake energy, and to disconnect the engine from the drive system of the wheels when driving with the motor, control so that the engine clutch is "disengaged" and use the motor and the engine together. Or, when starting / accelerating only by the engine, control is performed so as to be "contact".

[Problems to be solved by the invention]

In the case of such prior art, when recovering / regenerating brake energy using hydraulic pressure, control of a circuit valve (cutoff valve) in a hydraulic circuit is performed in an open loop, and control is actually performed as it is. In this case, the hydraulic circuit is closed without confirming whether or not the hydraulic pump has reached a state where the hydraulic pump has been closed. Therefore, there is a problem that cavitation occurs in the pump / motor in the hydraulic circuit due to a response delay of the circuit valve.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a brake energy regenerating device for a vehicle in which a close-out control is prevented by confirming an operation at the time of control of a circuit valve used in a hydraulic circuit and a pump / motor does not cause cavitation. And

[Means for solving the problem]

In order to achieve the above object, in a vehicle brake energy regenerating apparatus according to the present invention, a hydraulic circuit, pressure sensors respectively provided at four inlets and outlets of circuit valves constituting the hydraulic circuit, and an energy control circuit are provided. When controlling for regeneration or recovery, when the absolute value of the output difference between the pressure sensors on both sides of the circuit valve along the flow of oil is less than the resistance pressure in the pipeline of the hydraulic circuit, the operation of the circuit valve Hydraulic running
Control means for performing a hydraulic brake operation or a normal brake operation.

Further, in the present invention, when the circuit valve is controlled to be closed, when the absolute value of the output difference of the pressure sensor on the pump / motor side is substantially equal to the pipe resistance pressure in the pump / motor, Can be determined that the valve closing operation of the circuit valve is completed.

[Action]

In the present invention, when the control means controls a circuit valve provided in the hydraulic circuit for energy regeneration or recovery, oil flows from the high-pressure accumulator to the low-pressure accumulator or from the low-pressure accumulator to the high-pressure accumulator. Then, the absolute value of the pressure difference between the two pressure sensors sandwiching the circuit valve on both sides of the circuit valve, that is, the circuit valve is determined along the flow of the oil.

If the absolute value of each of the two pressure differences of the four pressure sensors is equal to or less than a predetermined resistance pressure in the pipeline of the hydraulic circuit, it is determined that oil is flowing normally in the hydraulic circuit. It can be confirmed that the predetermined operation for energy recovery / regeneration of the circuit valve has been completed.

Based on this, the control means performs hydraulic traveling, hydraulic brake operation or normal brake operation, for example, controls the tilting of the pump / motor of the hydraulic circuit as usual, and connects this hydraulic circuit to the PTO device via an electromagnetic clutch. It transmits braking energy from the wheels or driving energy to the wheels.

Further, in the present invention, when the circuit valve is closed, the absolute value of the output difference of the pressure sensor on the pump / motor side becomes
When the resistance value is substantially equal to the line resistance pressure in the motor, the control means can determine that the circuit valve has completed the shutoff operation of the hydraulic circuit, confirm the control of inhibiting the hydraulic control and, for example, deactivate the hydraulic circuit Can be kept in a state.

〔Example〕

FIG. 1 is a configuration diagram of an embodiment of a vehicle brake energy regenerating device to which the present invention is applied, and 1 is an axle.
A PTO device for taking out the driving force of the wheels 21 as hydraulic braking force via 20; an electromagnetic clutch 2 for disconnecting a driving force transmission between the PTO device 1 and a pump / motor 3 for performing a pump operation during braking; 4 is a circuit switching valve as a circuit valve,
Reference numeral 5 denotes a high-pressure accumulator, and reference numeral 6 denotes a low-pressure accumulator that forms a hydraulic circuit together with the pump / motor 3, the circuit switching valve 4, and the high-pressure accumulator 5. Further, between the high-pressure accumulator 5 and the circuit switching valve 6, between the circuit switching valve 6 and the pump / motor 3, between the pump / motor 3 and the circuit switching valve 4, and between the circuit switching valve 4 and the low-pressure accumulator 6. Pressure sensors 11 to 14 are attached between them, and send the oil pressure values of each part to the MPU 15 as control means. The MPU 15 is provided with a tilt angle (capacity) of the pump / motor 3.
Control, switching / cutoff control of the circuit switching valve 4, and opening / closing control of the electromagnetic clutch 2 are performed. Reference numeral 22 denotes an engine (not shown) including the PTO device 1 and an automatically controlled engine clutch 23.
In the case of a fluid control type transmission, the engine can be disconnected at the time of energy recovery / regeneration by setting the transmission at the neutral position.

The general operation of such a brake energy regenerating device will be described first.

Energy recovery mode Now, when an energy recovery mode command is given to the MPU 15 by, for example, depressing a brake pedal (not shown), the MPU 15 first controls the electromagnetic clutch 2 to the connected state, and sets the circuit switching valve 4 Switching control is performed as shown by the solid line.
The tilt angle (capacity) of the motor 3 is controlled.

Thereby, 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 regeneration mode As described above, the hydraulic energy stored in the high-pressure accumulator 5 is changed to an energy regeneration mode command by the driver depressing an accelerator pedal (not shown), for example.
The MPU 15 first controls the electromagnetic clutch 2 to the connected state, controls the circuit switching valve 4 as shown by the broken line, and changes the tilt angle of the pump / motor 3 to the depression amount of the accelerator pedal. Control according to.

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

Normal brake control mode In addition to this, there is a mode that does not use the hydraulic circuit at all,
In this case, the tilt angle of the pump / motor 3 is set to 0 (capacity 0), for example, so that the pump / motor 3 does not rotate even if pressure is applied to the pump / motor 3, and the circuit switching valve 4 is completely turned off. It is turned off (disconnected state), the hydraulic circuit is cut off, the electromagnetic clutch 2 is turned off, and the pump / motor 3 is turned off.
From the PTO device 1 and the wheels 21 to completely shut off the hydraulic braking force from the wheels 21.

As described above, in any mode, the MPU 15 controls the circuit switching valve 4, but as described above, if the next control is performed in a state where the control operation of the circuit switching valve 4 is not completed, the pump in the hydraulic circuit is -Cavitation occurs in the motor 3.

Therefore, in the present invention, the completion of the control operation of the circuit switching valve 4 is confirmed in each of the above modes as follows.

Operation Confirmation in Energy Recovery Mode (FIG. 2) First, when a switching control command for energy recovery is given from the MPU 15 to the circuit switching valve 4 (step S1 in FIG. 2), oil is removed in steps S2 and S3. Pressure sensors on both sides of the circuit switching valve 4 along the flow of
Absolute value of the pressure difference between |
_{11 -P 12 |, | P 13} -P 14 | look, determine the whether the absolute value is higher or lower than a certain pipeline resistance pressure P _R in the piping of the hydraulic circuit.

Then, when the lower steps S2 and S3 conduit resistance pressure P _R together only, for example, to generate a tilt angle control permission signal of the pump motor 3 (the step S4).

In this case, normally, P ₁₁ > P ₁₂ and P ₁₃ > P ₁₄ , but the absolute values are taken, for example, when there is a slight oil leak between the high-pressure accumulator 5 and the circuit switching valve 4. Is P ₁₁
<Because may also occur P ₁₂ the relationship. However, since the there is pipeline resistance pressure P _R or more differential pressure is considered to be circuit switching valve 4 not yet switching completion, not Utsura the next control, again in the next processing cycle of MPU15 step S2, S3
Will be checked.

Operation confirmation in energy regeneration mode (Fig. 3) When a switching control command for energy regeneration is given from the MPU 15 to the circuit switching valve 4 (step S1 in Fig. 3).
1) In steps S12 and S13, two pressure sensors on both sides of the circuit switching valve 4 along the flow of oil, that is, the sensors 11
Absolute value of the pressure difference between each of the sensors 13 and 13 and the sensors 12 and 14 | P
_{11 -P 12 |, | P 13} -P 14 | look, determine the whether the absolute value is higher or lower than a certain pipeline resistance pressure P _R in the piping of the hydraulic circuit.

Then, when the lower steps S12 and S13 conduit resistance pressure P _R together only, for example, to generate a tilt angle control signal of the pump motor 3 (the step S14).

In this case as well, the completion of the switching operation of the circuit switching valve 4 is determined similarly by taking the absolute value.

Operation Confirmation in Normal Brake Control Mode (FIG. 4) The MPU 15 controls the circuit switching valve 4 to close the valve as a normal brake control mode command (step S21 in FIG. 4). Thereafter, the absolute value | P ₁₂ −P ₁₃ | of the pressure difference between the pressure sensors 12 and 13 on the pump / motor side of the circuit switching valve 4 is obtained, and this absolute value is determined as a fixed line in the pump / motor 3. determines higher or lower or a more resistive pressure P _M (step S22).

Then, | P ₁₂ -P ₁₃ | indicates equal to pipeline resistance pressure P _M and the substantially hydraulic differential pump motor 2 itself in the line resistance pressure across the pump motor 2 when equal And
This indicates that the circuit switching valve 4 has completed the shut-off state.

Therefore, in such a case, for example, a hydraulic circuit open state signal is generated (step S23).

In this way, the operation is confirmed in each control mode of the circuit switching valve.

In the above-described embodiment, when each checking operation is completed, the tilting of the pump / motor 3 may be controlled immediately, or this state may be stored in a flag or the like as described above, and the state may be stored later. The control may be performed in consideration of other flags.

Although the electromagnetic clutch is not shown in FIGS. 2 to 4, the electromagnetic clutch is controlled in a connected state before controlling the circuit valve, and a constant load is applied to the pump / motor. It is usual to give.

Also, the circuit switching valve has been described as a circuit valve,
Depending on the type of pump / motor, a simple circuit shut-off valve that does not need to switch the hydraulic circuit can be similarly performed.

〔The invention's effect〕

As described above, in the vehicle brake energy regenerating apparatus according to the present invention, the pressure sensors are provided at the four inlets and outlets of the circuit valves provided in the hydraulic circuit, respectively. When the absolute value of the output difference between the pressure sensors on both sides of the circuit valve along the flow is equal to or less than the resistance pressure in the pipeline of the hydraulic circuit, (2) When the circuit valve is controlled to close, the pressure on the pump / motor side When the absolute value of the output difference of the sensor is substantially equal to the line resistance pressure in the pump / motor, it is determined that the circuit valve has completed the predetermined operation, and the hydraulic traveling, hydraulic braking operation or normal braking operation is performed. Since it is configured to perform the operation, it is possible to prevent the occurrence of cavitation of the pump / motor due to the operation delay of the circuit valve during the close-out control, and to avoid an abnormal hydraulic control state.

[Brief description of the drawings]

1 is a diagram showing a configuration of an embodiment to which a vehicle brake energy regenerating device according to the present invention is applied, and FIG. 2 is a flowchart showing a check operation of a circuit valve switching operation in an energy recovery mode according to the present invention. FIG. 3 is a flowchart showing a check operation of a circuit valve switching operation in the energy regeneration mode according to the present invention. FIG. 4 is a flowchart showing a check operation of a circuit valve closing operation in the normal brake control mode according to the present invention. FIG. In FIG. 1, 3 is a pump motor, 4 is a circuit switching valve, 5 is a high-pressure accumulator, 6 is a low-pressure accumulator, and 15 is an MPU.

Claims (2)

(57) [Claims] 1. A hydraulic circuit, pressure sensors provided at four inlets and outlets of circuit valves constituting the hydraulic circuit, respectively, and when the circuit valves are controlled for energy regeneration or recovery, the circuit valves follow a flow of oil. When the absolute value of the output difference between the pressure sensors on both sides of the circuit valve is equal to or less than the resistance pressure in the pipeline of the hydraulic circuit, the operation of the circuit valve is determined to be completed, and the hydraulic traveling, hydraulic braking operation or normal braking operation is performed. And a control means for performing the following. 2. When the circuit valve is controlled to close, when the absolute value of the output difference of the pressure sensor on the pump / motor side is substantially equal to the line resistance pressure in the pump / motor, the control means includes: The apparatus according to claim 1, wherein it is determined that the closing operation of the circuit valve is completed.