JPH07144621A - Brake energy regenerating device - Google Patents

Abstract

PURPOSE:To prevent the breakage of a pump/motor and the impact vibration due to the reverse revolution of the pump/motor, during the reverse traveling of a vehicle. CONSTITUTION:When it is detected that the speed change stage of a transmission is at a reverse stage, by a T/M reverse sensor (S70), the control for a hydraulic pump/motor is suspended (S75, S76), and even if it is not detected that the speed change stage is at the reverse stage (S70 and S71), the control suspended state is maintained until the car speed becomes zero (S72, S75, and S76).

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a pressure-accumulation type braking energy regenerator that utilizes the braking energy of a vehicle as starting / accelerating energy using hydraulic oil as an energy transmission medium.

[0002]

2. Description of the Related Art Conventionally, a braking energy regenerator, which is mounted on a vehicle such as a city bus, collects energy at the time of braking and utilizes it at the time of starting or accelerating, for example, Japanese Patent Publication No. 5-11.
No. 68 publication. This braking energy regeneration device operates a pump / motor as a pump when the vehicle is being braked, pumps hydraulic oil in a low-pressure tank to an accumulator, and stores braking energy therein. When the vehicle starts or accelerates (these are also simply referred to as start / acceleration), the high-pressure hydraulic oil of the accumulator is supplied to the pump / motor to operate the pump / motor as a motor to drive the vehicle drive wheels. Is driven by a pump / motor, which reuses the braking energy.

The hydraulic pump / motor connected to the drive shaft of the braking energy regenerative device as described above has a fixed rotational direction in which it functions due to structural reasons. Then, when the vehicle moves backward, the pump / motor rotates in the reverse direction, and the pump / motor does not function as a pump or a motor. Therefore, when the gear position of the transmission (transmission) is at the reverse gear position (reverse), both the pump control and the motor control are stopped so that the pump / motor does not function, and the gear position is the reverse gear position (reverse). ), It works as a pump or a motor.

[0004]

When the gear position of the transmission is detected to be in the reverse gear position (reverse) and the pump control or the motor control is stopped, the gear position other than the reverse gear is shifted to the reverse gear position. Although the step position (reverse) is not detected, even in such a case,
The vehicle itself may continue to run backwards.

In such a case, although the drive wheels reversely rotate due to the backward running of the vehicle and the pump / motor also maintains the reverse rotation state, the pump / motor control is already in the original correct state. When it is determined that the rotation operation is possible, for example, when the motor control is started, high pressure hydraulic oil is supplied from the accumulator, and it is impossible to rotate the pump / motor in the reverse direction. Force is applied to the pump / motor, which causes troubles such as damage to the pump / motor, and gives a large impact vibration to the vehicle, which shortens the life of the device and the vehicle.

[0006] Therefore, the present invention occurs when an unreasonable load is applied to the vehicle while the vehicle is traveling in reverse without surely operating the pump or the motor.
An object of the present invention is to provide a braking energy regenerative device designed to prevent damage to a pump / motor and shock vibration.

[0007]

In order to achieve the above object, the braking energy regenerating apparatus of the present invention is provided in an oil passage between a low pressure tank for storing hydraulic oil and an accumulator for accumulating hydraulic energy. , A hydraulic pump / motor connected to a drive system member of a vehicle via a clutch is operated during braking, the braking energy is converted into hydraulic energy and stored in the accumulator, while the motor is operated during start / acceleration. In a braking energy regeneration device that uses hydraulic energy accumulated in an accumulator as start / acceleration energy, a reverse gear detecting means for detecting that the gear stage of a transmission of a vehicle is in a reverse gear, and a vehicle speed detecting means for detecting a vehicle speed. And a control means for controlling the operation of the hydraulic pump / motor according to the traveling state of the vehicle, the control means comprising: And but to detect that it is in the reverse gear,
When the control of the hydraulic pump / motor is stopped and the control is stopped, the control stop state is maintained until the vehicle speed becomes substantially zero even if it is no longer detected that the shift stage is in the reverse stage. It is characterized in that it is configured to maintain.

[0008]

[Function] Even if it is no longer detected that the gear position is in the reverse gear after it is detected that the gear position is in the reverse gear, the hydraulic pump / motor control is stopped, and the vehicle travels backward, The control stop state is maintained until it becomes zero, and the control of the hydraulic pump / motor is not restarted as long as the vehicle is traveling in reverse.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described with reference to the drawings. The energy regeneration device shown in FIGS. 1, 2 and 3 is applied to a vehicle including an engine 1 for driving drive wheels via a transmission 3 and a clutch 2, and a piston type accumulator 20, a low pressure hydraulic oil tank 30, Swash plate type variable displacement piston type pump / motor 40, gear box 50, control unit 60 (hereinafter referred to as EC
(Referred to as U).

First, the structure of a vehicle to which the energy regeneration device is applied will be described. The output shaft of the engine 1 is connected to the transmission 3 via the clutch 2, and the output shaft 13 of the transmission 3 is the rear wheel drive shaft 10. It is connected to a differential device (through shaft type). The energy regeneration device is connected to the above-described differential device via the drive shaft 12. The transmission 3 has one reverse gear and five forward gears.

The accumulator 20 is connected to the first port 40a of the swash plate type variable displacement piston type pump / motor 40 through the high pressure oil pipe line P1 and is connected to the pump / motor 4
The second port 40b of 0 is connected to the hydraulic oil tank 30 via the low pressure oil pipe P2. Accumulator 20
Is divided into a gas chamber 22 and a hydraulic oil chamber 23 by a piston 21, and the gas chamber 22 is filled with nitrogen gas at a predetermined pressure.
Hydraulic pressure can be stored in the hydraulic oil chamber 23.

An accumulator 20 is installed in the high pressure oil line P1.
A shutoff valve 24 and an unload valve (normally open) 25 are arranged in this order from the side. The shutoff valve 24 is an electromagnetic pilot operated valve and normally functions as a check valve that allows the flow of the hydraulic oil from the pump / motor 40 to the accumulator 20 and blocks the flow in the opposite direction.
When the shutoff valve signal D2 from 60 is input, the flow of hydraulic oil from the accumulator 20 side to the pump / motor 40 side is allowed. The electromagnetic unload valve 25 is operated by the unload valve signal D3 from the ECU 60, short-circuits the high-pressure oil pipeline P1 and the low-pressure oil pipeline P2 via the pipeline P4, and the residual pressure trapped in the high-pressure oil pipeline P1. Can be released to the low-pressure oil pipe line P2.

Between the high pressure oil line P1 and the low pressure oil line P2,
A check valve 46 is provided, and the check valve 46 has a low-pressure oil line P.
The hydraulic oil can flow into the high-pressure oil pipeline P1 from 2 to prevent damage to the device or the like caused by running out of hydraulic oil in the high-pressure oil pipeline P1. Further, the high pressure oil pipe P1 on the pump / motor 40 side from the shutoff valve 24 is branched to connect the pipe P3 to the hydraulic oil tank 30, and the discharge pressure of the pump / motor 40 is set to this pipe P3 by the set pressure ( For example, 3
A relief valve 26 is provided for releasing high-pressure oil to the hydraulic oil tank 30 when the pressure exceeds 50 kgf / cm ² ).

The high-pressure oil line P1 is provided with a discharge pressure sensor 89 for knowing the pipe pressure on the pump / motor 40 side from the shutoff valve 24, and supplies a discharge pressure signal PHY to the ECU. When the piston 21 moves to a predetermined position (referred to as the immediately preceding position) slightly before the maximum expansion position of the hydraulic oil chamber 23 due to the expansion of the nitrogen gas, the accumulator 20 detects this and detects the piston position signal (OFF signal). LP
Is provided, and a pressure accumulation sensor 88 that detects the hydraulic pressure in the hydraulic oil chamber 23 and outputs a pressure accumulation signal PAC is provided.
The P and the pressure accumulation signal PAC are supplied to the ECU 60.

The pump / motor 40 includes a gearbox 50.
The driving shaft 12 is connected to the drive shaft 12 via the gearbox 50.
Is transmitted to the pump / motor 40 via the
The start / acceleration energy of the motor 40 is
Is transmitted to the drive shaft 10 via the drive shaft 12 and the differential device. The gear box 50 is composed of a pair of gears 50a and a dog clutch 51, and the pair of gears 50a accelerates the rotation of the drive shaft 12 and transmits it to the pump / motor 40.
The connection between the drive shaft 12 and the pump / motor 40 is connected / disconnected by the dog clutch 51.

The pump / motor 40 includes a gearbox 50.
Drive shaft 40e connected to the output shaft of the piston, a piston cylinder 40f that rotates integrally with the drive shaft 40e, a piston 40c fitted in the cylinder 40f, and a swash plate that reciprocates the piston 40c as the drive shaft 40e rotates. 40d, the pump / motor capacity is set by controlling the angle of the swash plate 40d with respect to the drive shaft 40e, that is, the tilt angle, and rotates in the same direction both when the pump is operating and when the motor is operating. It is like this.

The tilt angle of the swash plate 40d depends on the tilt cylinder 41.
Variably controlled by. The tilt cylinder 41 includes a piston 41a connected to a swash plate 40d and a piston 41a.
Chambers 41b and 41 formed on both sides of 1a, respectively.
c, and when one chamber, for example, the chamber 41b, is supplied with a pilot oil pressure from a pilot oil pressure source 43 described later, the swash plate 40d is driven to the pump operating side, and the other chamber 41c is supplied with the pilot oil pressure. And it is designed to be driven to the motor operating side.

The pilot hydraulic pressure source 43 is composed of an oil pump driven by an electric motor or the like and a pressure regulating valve, and generates a pilot hydraulic pressure of a predetermined pressure. A filter 45, an electromagnetic two-port switching valve 44, and a proportional solenoid valve 42 are arranged in this order between the hydraulic power source 43 and the tilt cylinder 41.
These are the pilot hydraulic power source 43 and the tilt cylinder 41.
A pilot hydraulic pressure control circuit for controlling the supply pressure of the pilot hydraulic pressure to the pump is configured. The switching valve 44 is an ECU
The drive signal D1 from the pilot oil passage P5
To connect and disconnect.

When the control signal ELP is supplied to one solenoid of the proportional solenoid valve 42, for example, the solenoid 42a, a pilot hydraulic pressure having a magnitude corresponding to the signal value ELP is supplied to the pump operating side of the tilt cylinder 41 via the proportional solenoid valve 42. When the control signal ELM is supplied to the chamber 41b and the other solenoid 42b is supplied, a pilot hydraulic pressure having a magnitude corresponding to the signal value ELM is supplied to the chamber 41c on the motor operating side.
As a result, the operating position of the piston 41a of the tilt cylinder 41, and by extension, the tilt angle of the swash plate 40d, is variably controlled, and when the pump is operating, the discharge amount is adjusted and when the motor is operating. In that case, the output torque is adjusted.

When the pump of the pump / motor 40 is operating,
The swash plate 40d is driven to the pump operating side by the tilting cylinder 41, and the working oil flows from the working oil tank 30 to the filter 3
8, the check valve 58, the pipe line P2, the pump / motor 40, and the pipe line P1 to the accumulator 20, and when the motor is operating, the swash plate 40d is driven to the motor operating side, and the hydraulic oil is different from that when the pump is operating. In the opposite direction, from accumulator 20 to line P1, pump / motor 40, line P2, check valve 57,
It flows to the hydraulic oil tank 30 via the filter 37.

The hydraulic oil tank 30 is connected to the pressurized air tank 31 via the electromagnetic two-port switching valve 33, the pressure reducing valve 35, and the air dryer 36, and the electromagnetic three-port switching valve 34.
Are connected to the sub air tank 32 via the, and these constitute an air pressure supply circuit to the hydraulic oil tank 30. The switching valve 34 is operated by the drive signal D7 from the ECU 60, and the sub air tank 32 and the hydraulic oil tank 30 are operated.
It can be switched to a position that allows communication with. Sub air tank 3
By communicating 2 with the hydraulic oil tank 30, the sub air tank 32 supplies a part of the reserved air to the hydraulic oil tank 30, and also according to the fluctuation of the hydraulic oil amount in the hydraulic oil tank 30. The air pressure in the hydraulic oil tank 30 is stabilized by supplying or absorbing air. On the other hand, ECU
When the drive signal D7 from 60 is cut off, the switching valve 34
It switches to the atmosphere release position, and the pressure in the hydraulic oil tank 30 is released to the atmosphere.

The switching valve 33 is operated by a drive signal D6 from the ECU 60, supplies the high-pressure air in the air tank 31 into the hydraulic oil tank 30, and pressurizes the hydraulic oil in the tank 30 to a predetermined pressure to pump the pump. / Keep the operation of the motor 40 in a stable state. The hydraulic oil leaking from the pump / motor 40, the fitting portion (oil seal) in the hydraulic path, and the like flows back to the drain tank 39. The drain tank 39 is connected to the hydraulic oil tank 30 via a pump 59, a filter 97, and an electromagnetic two-port switching valve 98. When the hydraulic oil in the drain tank 39 reaches a predetermined amount, the pump 59 is operated. , The ECU 60 outputs a drive signal to the switching valve 98, opens the drive signal, and supplies the insufficient operating oil to the operating oil tank 3
Add to 0.

The hydraulic oil tank 30 is provided with a hydraulic oil level sensor 90 and an oil temperature sensor 91, which supply a hydraulic oil level signal LOIL and an oil temperature signal TOIL to the ECU 60, respectively. The ECU 60 uses these signals to
By monitoring whether or not the hydraulic oil is in a normal state and regulating the operation of the regenerative device, damage to the pump / motor 40 and other devices is prevented.

The dog clutch 51 described above is connected and disconnected by air pressure, and the dog clutch 51 includes an electromagnetic 3-port switching valve (also referred to as a dog clutch contact valve) 53 for clutch connection and an electromagnetic 3-port switching for clutch disconnection. An air tank 52 is connected via a valve (also referred to as a dog clutch shutoff valve) 54, and these constitute a dog clutch operation control circuit. The switching valve 53 for connecting the clutch is
When actuated by the drive signal D8 from the ECU 60, the high pressure air in the air tank 52 is supplied to the dog clutch 51, the dog clutch 51 is engaged, and the clutch disconnecting switching valve 54 is actuated by the drive signal D from the ECU 60.
When operated by 9, the dog clutch 51 is disengaged. Once the connection of the dog clutch 51 is confirmed by the operation of the switching valve 53 and the disconnection thereof is confirmed by the operation of the switching valve 54, the dog clutch 51 is connected or disconnected even if the drive signals of the switching valve 53 and the switching valve 54 are cut off. It is structured to hold.

The dog clutch 51 is provided with a dog clutch connection / disconnection sensor (also referred to as connection / disconnection SW) 92 for detecting the connection / disconnection state of the dog clutch 51, and detecting signal D thereof.
CL is supplied to the ECU 60. Further, the pump / motor-side output shaft of the dog clutch 51 is connected to the pump / motor 4
A rotation speed sensor 93 for detecting the rotation speed of 0 is provided and supplies a pump rotation speed signal NP to the ECU 60.

The brake power unit 70 connected to a brake pedal (not shown) is for controlling the braking force of the drive wheel WR and the driven wheel WF, and brakes the wheel cylinder (not shown) of each wheel. Supplying air pressure. A brake pressure PBK generated according to the degree of operation of a brake pedal (not shown) is detected by a sensor (not shown), and a brake pressure detection signal PBK is sent to the ECU 60.
Is being supplied. The ECU 60 compares the magnitudes of the discharge pressure PHY and the brake pressure PBK of the pump / motor 40, which are detected by the discharge pressure sensor 89 described above, with their respective predetermined values, thereby accumulating brake by the pump operation of the pump / motor 40. And normal service brake operation switching control.

The engine 1 is provided with a fuel injection device 5, and the governor control unit 67 connected to the fuel injection device 5 performs normal fuel injection control, and a rack limit signal R from the ECU 60 described later. Fuel injection limitation (rack limitation). This fuel injection limitation (rack limitation) is controlled so that the sum of the output of the pump / motor 40 operating by the motor and the output of the engine 1 does not exceed the output corresponding to the drive torque of the normal engine 1 alone. Is. The governor control unit 67 also detects the engine speed NE and supplies the engine speed signal NE to the ECU 60.

The transmission 3 includes a vehicle speed sensor 83 as a vehicle speed detecting means and a T / as a reverse speed detecting means.
M reverse sensor 84, T / M neutral sensor 85
And a select position sensor 86 are provided, and the vehicle speed signal V, the T / M reverse signal TMR, the T / M neutral signal TMN and the select position signal LTM are set to E, respectively.
It is supplied to the CU60.

FIG. 3 shows the configuration of the ECU 60 for controlling the operation of the energy regeneration device. The ECU 60 is equipped with a processor, a memory, an input / output circuit and the like. This ECU 6
The input side of 0 is interlocked with a main SW 64 that supplies a power ON / OFF state signal and an accelerator pedal (not shown),
An accelerator opening sensor 61 that detects the amount of depression of the accelerator pedal, and two clutch sensors (C
L1) 62, (CL2) 63, and various sensors including the brake pressure sensor described above are connected. Here, the engine clutch connection / disconnection sensor (CL1) 62 is set to supply a signal at the return limit (clutch connection) of the clutch pedal (not shown) to be turned on, and the engine clutch connection / disconnection sensor (CL2). ) 63 is set to supply a signal at the depression limit (clutch disengagement) of the clutch pedal (not shown) to be turned on, and the sensor (CL1) 6
The half-clutch state can be detected by the combination of 2 and the sensor (CL2) 63.

On the other hand, the above-mentioned various electromagnetic switching valves and various indicators are connected to the output side of the ECU 60. The indicators include the piston position signal LP from the piston sensor 87 of the accumulator and the pressure accumulation sensor 88.
A pressure accumulation indicator 66 for displaying the amount of pressure accumulated by the pressure accumulation signal PAC from the regenerative lamp 68 for indicating that the energy regeneration device is in operation by the dog clutch engagement / disengagement signal DCL from the dog clutch engagement / disengagement sensor 92 and various errors (abnormality). There is a diagnostic lamp 69 that indicates an error by a signal.

The pump control and motor control of the braking energy regenerating device constructed as described above will be described below with reference to the flow charts shown in FIGS. Figure 4,
5 and 6 show a control procedure of pump control during braking, which is executed by the ECU 60. First, the ECU 60 turns on the dog clutch 51 by the dog clutch connection / disconnection signal DCL from the dog clutch connection / disconnection sensor 92 in step S10.
It is determined whether (connection) or OFF (disconnection). It should be noted that the dog clutch 51 is controlled by the ECU 60 when the vehicle is in a predetermined clutch connection operation state by a dog clutch control described later.
Drive signal D8 is supplied to the clutch connection switching valve 53 from ON to ON (connect), and in a predetermined clutch disengagement operation state, the drive signal D9 is supplied to the disconnection switching valve 54 and O
It becomes FF (cut). When the dog clutch 51 is in the connected state, the pump / motor 40 is driven by the drive wheel WR via the drive shafts 10, 12 and the gear box 50.

If the determination result of step S10 is OFF (disconnection), the process proceeds to step S20 of FIG. ECU60
Sets the tilt angle control signal value ELP to the proportional solenoid valve 42 to zero (ELP = 0) in step S20. As a result, the pilot oil pressure from the pilot oil pressure source 43 is held in a cutoff state, and the piston 41a of the tilt angle cylinder 41 is also held in the neutral position. Then, by keeping the tilt angle of the swash plate 40d of the pump / motor 40 at zero, the pump / motor 40 does not function as a pump. Next, in step S21, the drive signal D1 to the switching valve 44 is kept turned off and is set to O.
The FF (closed) state is maintained, and in step S22, the unload valve signal D3 is not output to the unload valve (normally open) 25, and it is turned OFF (open) to set the high pressure oil line P1 and the low pressure oil line P1. It is kept in communication with P2. In step S23, the ECU 60 sets a value 0 (f1 = 0) to the flag f1 which is a program control variable,
As a result, it is stored that the pump control is not executed.

Returning to step S10 in FIG. 4, if the determination result in this step is the ON (connection) state, the process proceeds to step S11. In step S11, the ECU 60 determines whether the vehicle is traveling in reverse or is in the pump control prohibiting operation after releasing the reverse gear. This determination is made based on whether or not a flag f (R) described later is equal to the value 1. If the flag f (R) is equal to the value 1, the pump control is prohibited, and the above step S20 and the following steps are executed. On the other hand, if the determination result of step S11 is NO (f (R) = 0), the process proceeds to step S12.

In step S12, the ECU 60 determines whether or not the vehicle is stopped. This determination is based on the vehicle speed V
Is below a predetermined value XV0 (for example, 1 km / h) by the vehicle speed signal V. If V ≦ XV0 (1 km / h), pump control is not executed. On the other hand, the determination result is V> XV0 (1km
/ h), execute step S13. Step S1
In 3, the ECU 60 determines whether or not the brake pressure PBK is generated by the driver stepping on the brake pedal (not shown).
Judging by BK, PBK <XPB (for example, 0.2 kgf / cm
^{In case of 2} ), it is considered that the brake pedal (not shown) is not depressed and the pump control is not executed. On the other hand, if the determination result is PBK ≧ XPB (0.2 kgf / cm ² ), it is determined that all the operating conditions for regenerating energy are satisfied,
Step S14 is executed.

In step S14, the ECU 60 controls the tilt angle control signal value ELP of the swash plate 40d of the pump / motor 40.
Execute the subroutine that sets. As a method of setting the ELP value, for example, a reference value corresponding to the brake pressure PBK is calculated, and the reference value is detected by the oil temperature TOIL detected by the oil temperature sensor 91 of the hydraulic oil tank and the vehicle speed sensor 83. It is corrected by the vehicle speed V, the accumulated pressure amount PAC of the accumulator 20, etc., and set to an appropriate value. FIG. 11 shows the ECU 60.
Shows an ELP reference value map stored in the storage device, and the ECU 60 reads an ELP reference value corresponding to the brake pressure PBK from this map.

Next, in step S15 of FIG. 5, E
The CU 60 outputs a control signal corresponding to the ELP value set as described above to the proportional solenoid valve 42, and sets the tilt angle of the pump / motor 40 to the angle corresponding to the signal value ELP. Next, in step S16, the drive signal D1 is output to the switching valve 44 to turn it ON (open), and the pilot hydraulic pressure is supplied to the tilt angle cylinder 41. In step S17, the unload valve (normally open) 25 between the low-pressure oil pipeline P2 and the high-pressure oil pipeline P1 is turned on (closed) by the unload valve signal D3, and the pressure of the high-pressure oil pipeline P1 is changed to the low-pressure oil pipeline P2. Shut off to prevent escape. Further, in step S18, the value 1 is set in the flag f1 in order to store that the pump is operating.

In this way, when the tilt angle of the pump / motor 40 is set to the angle corresponding to the control signal value ELP to the proportional solenoid valve 42, the pump / motor 40 operates as a pump and the hydraulic oil tank The hydraulic oil of 30 is sucked and pushed into the hydraulic oil chamber 23 of the accumulator 20 to accumulate pressure. In the above pump control, the tilt angle of the pump / motor 40 is set according to the amount of brake pedal depression by the driver, and the pump / motor 40 performs work according to the amount of brake pedal depression and performs braking. Energy will be recovered.

7 to 10 show a control procedure of motor control at the time of starting and accelerating (starting / accelerating). First, E
Before starting the motor operation, the CU 60 determines whether or not the motor control may be executed in steps S30 to S40. In step S30, it is determined whether or not the driver intends to start the vehicle based on whether or not the brake pressure PBK is smaller than a predetermined value XPB (for example, 0.2 kgf / cm ² ). If the determination result of step S30 is PBK ≧ XPB (0.2 kgf / cm ² ), step S50 and subsequent steps of FIG. 10 described later are executed and motor control is not performed. On the other hand, the discrimination result is PBK <XPB (0.2 kgf / cm
^{If 2} ), the process proceeds to step S31.

In step S31, the ECU 60 determines whether or not the pump is being controlled, depending on whether the flag f1 indicating that the pump is being controlled is 1 (YES) or 0 (NO). When the flag f1 is 1 (YES), that is, during pump control, step S50 and subsequent steps in FIG. 10 described later are executed and motor control is not executed. On the other hand, when the flag f1 is 0 (NO), that is, when the pump control is not in progress, the process proceeds to step S32.

In step S32, the ECU 60 determines whether the dog clutch engagement / disengagement sensor 92 is ON (connected) or OFF (disengaged) based on the dog clutch engagement / disengagement signal DCL, and O
If it is FF (cut), motor control is not executed. on the other hand,
If the determination result is ON (connection), the process proceeds to step S33. In step S33, the ECU 60 determines whether or not the vehicle is traveling in reverse or is in the motor control prohibited operation after releasing the reverse gear. This determination is made depending on whether or not the flag f (R) is equal to the value 1, and the method of setting the flag value will be described later. If the flag f (R) is equal to the value 1, the motor control is prohibited, and step S50 described later is performed.
Do the following: On the other hand, the determination result of step S33 is N
If O (f (R) = 0), the process proceeds to step S34.

In step S34, the ECU 60 determines whether or not the selected position of the transmission 3 is neutral by the T / M neutral signal TMN.
If the determination result is YES (neutral), that is, if the select position is neutral, it is determined that the driver has no intention of starting the vehicle, and motor control is not performed. On the other hand, when the determination result is NO, the process proceeds to step S35.

In step S35, the ECU 60 determines whether the clutch 2 is in the engaged state or the disengaged state by the clutch engagement / disengagement signal CL2 of the clutch engagement / disengagement sensor (CL2) 63, and if it is in the disengaged state, the selected position of the transmission 3 is selected. The motor control is not performed as in the case where is neutral. On the other hand, in the connected state (including the half-clutch state), the process proceeds to step S36 in FIG.

In step S36, the ECU 60 determines whether the accumulator 20 is filled with hydraulic oil.
It is determined by the piston position signal LP from the piston position sensor 87. When the piston position sensor 87 set to the immediately preceding position of the piston 21 is 0FF, that is, when the hydraulic oil is empty, it means that the hydraulic oil is not accumulated in the accumulator 20. In such a case, the motor control is executed. do not do. On the other hand, the piston position sensor 87 is ON
That is, when the accumulator 20 is filled with hydraulic oil, the process proceeds to step S37.

In step S37, the ECU 60 determines from the vehicle speed signal V whether the vehicle speed V is equal to or lower than a predetermined value XV2 (for example, 65 km / h), and if it is higher than the predetermined value XV2 (65 km / h). In order to prevent the pump / motor 40 from being damaged beyond the allowable capacity, no motor control is performed. On the other hand, if it is less than or equal to the predetermined value XV2 (65 km / h), the process proceeds to step S38.

In step S38, the ECU 60 sets the vehicle speed V to the predetermined value XV1 (for example, 5 km) as in step S37.
/ h), if it is smaller than the XV1 value, step S3
9, the clutch connection / disconnection sensor (CL1) 6 is used to determine whether the clutch 2 is completely engaged or in the half-clutch state.
It is determined by the clutch connection / disconnection signal CL1 of 2. According to the determination in step S38, the vehicle speed V is a predetermined value XV1 (5 km / h)
If it is determined that the clutch 2 is completely engaged even though it is smaller, it is determined that there is some abnormality in the clutch sensors 62, 63, the vehicle speed sensor 83, etc. Motor control is not performed. On the other hand, when the clutch connection / disconnection signal CL1 indicates the OFF state, the clutch 2 is combined with the determination result of step S35 described above.
Means that it is in a half-clutch state, and in such a case, the process proceeds to step S40.

In step S40, the ECU 60 determines from the accelerator opening signal L Aθ whether or not the accelerator opening L Aθ is larger than the motor start opening determination value Xθ1. The above-mentioned discriminant value Xθ1 is set according to the vehicle speed V,
FIG. 12 shows the vehicle speed V and the discriminant value X set accordingly.
It shows the relationship with θ1. When the accelerator opening L Aθ is smaller than the discriminant value Xθ1 (L Aθ <Xθ1), it is determined that the vehicle should not be accelerated by the regenerative energy, and the motor is not operated. If the motor control is executed when the load is such that the accelerator opening LAθ is equal to or smaller than the determination value Xθ1, it becomes necessary to greatly reduce the engine output. But,
If the engine output is reduced too much, the fuel consumption characteristics of the engine will deteriorate, which is rather undesirable. On the other hand, if it is larger than the discriminant value Xθ1 (L Aθ ≧ Xθ1), step S4
The process proceeds to 1 to start the motor control.

When the motor control is not executed, the ECU
60 is the proportional solenoid valve 4 in step S50 of FIG.
The tilt angle control signal value ELM for 2 is set to zero (ELM = 0) and is output. As a result, the tilt angle cylinder 4
The first piston 41a is held in the neutral position, the tilt angle of the swash plate 40d of the pump / motor 40 becomes zero, and the pump / motor 40 does not function as a motor. In step S51, the piston 41 of the tilt angle cylinder 41 is
Switching valve 44 for controlling supply / discharge of pilot oil for driving a
Is turned OFF (closed) by cutting off the drive signal D1. In step S52, the shutoff valve 24 that is ON (open) when the motor is operating is turned OFF (closed) by shutting off the shutoff valve signal D2, and the flow of hydraulic oil from the accumulator 20 to the pump / motor 40 is stopped. In step S53, the unload valve (normally open) 25 arranged between the low pressure oil pipeline P2 and the high pressure oil pipeline P1 is turned off (open) by stopping the output of the unload valve signal D3, and the high pressure oil pipeline P1. And low pressure oil line P
Connect two. In step S54, a rack limit signal R, which will be described later, transmitted to the engine 1 when the motor is operating is cut off and turned OFF. Further, in step S55, the rack limit valid signal RE similarly transmitted is cut off.
Let it be F. Finally, in step S56, a value 0 (f2 = 0) is set to the flag f2, which is a program control variable, and it is stored that the motor control is not executed.

On the other hand, when the motor control is started by executing step S41, the ECU 60 controls the pump / motor 4
A subroutine for setting the tilt angle control signal value ELM of the swash plate 40d of 0 is executed. As the setting method of ELM value,
First, a reference value is set according to the accelerator opening L Aθ and the vehicle speed V (instead of the vehicle speed V, the engine speed NE may be used). FIG. 13 shows an ELM map stored in the storage device of the ECU 60, and the ECU 60 reads the ELM reference values (XM0, XM1, ...) According to the vehicle speed V and the accelerator opening L Aθ from this map. Next, a correction coefficient according to the oil temperature of the hydraulic oil tank 30 detected by the oil temperature sensor 91 is obtained, and this is multiplied by the ELM reference value to calculate the optimum tilt angle control signal ELM value. . Changing the tilt angle control signal value ELM according to the accelerator opening L Aθ allows the motor of the pump / motor 40 to obtain a response similar to the response of the accelerator operation at the time of starting and accelerating only by the normal engine 1. This is to change the output torque value due to the operation. Further, the tilt angle control signal value EL is changed depending on the vehicle speed V (or the engine speed NE).
Changing M supplies high torque in the low speed range,
In the medium speed range, it is possible to supply the torque required for acceleration.

The correction based on the oil temperature of the hydraulic oil tank 30 does not require the correction of the ELM value when the oil temperature is lower than 70 ° C., but when the oil temperature is 70 ° C. or higher, the tilt angle control signal value ELM.
Is corrected so that When the temperature is high, the viscosity of the hydraulic oil is reduced, and the pump / motor 40 may be burnt. Therefore, this is prevented by reducing the motor capacity.

Next, the ECU 60 executes step S4 in FIG.
2, the control signal corresponding to the ELM value set as described above is output to the proportional solenoid valve 42, and step S4
In 3, the drive signal D1 is output and the switching valve 44 is turned on.
(Open) and the tilting angle cylinder 4 through the proportional solenoid valve 42.
Supply pilot pressure to 1. This allows the pump /
The swash plate 40d of the motor 40 is set to a tilt angle corresponding to the ELM value. Next, in step S44, the shutoff valve 26
The shutoff valve signal D2 is outputted to ON (open), and the unload valve signal D3 is supplied to the unload valve (normally open) 25 in step S45 to turn it ON (close). The pressure in the high-pressure oil pipeline P1 is shut off so as not to escape to the low-pressure oil pipeline P2. This allows
The pump / motor 40 is driven by the high pressure hydraulic oil accumulated in the accumulator, and its driving force is the drive shaft 4
0e, the gear box 50, the drive shafts 12 and 10, and is transmitted to the drive wheels WR to cover a part of the driving force at the time of starting or accelerating.

In step S46, the ECU 60 supplies a rack limit signal R for limiting the fuel supply of the fuel injection device 5 of the engine 1 to the fuel injection device 5 via the governor control unit 67. The rack limit signal R limits the output torque on the engine 1 side during motor control, and the output limit amount on the engine 1 side is
It is determined based on the engine speed NE and the pressure accumulation amount PAC of the accumulator 20. Then, in order to reliably execute the output limitation on the engine 1 side supplied to the fuel injection device 5, in step S47, the rack limitation effective signal RE is output to the governor control unit 67 to prevent malfunction due to noise or the like. is doing. Finally step S
At 48, the program control variable flag f2 is set to the value 1 to store the fact that the motor is operating.

14 to 17 show a dog clutch control subroutine executed by the ECU 60 in a predetermined control cycle, and the engagement / disconnection of the dog clutch 51 is controlled by executing this routine. The ECU 60 first determines in step S70 whether or not the selected position of the transmission 3 is the reverse gear (reverse).
If the result of the determination is YES (reverse), that is, if the vehicle is in the reverse gear, the step S75 is executed to set the flag f (R), which is a program control variable, to the value 1 ( f (R) = 1) is set, and the fact that the reverse control is being performed is stored. When the flag f (R) is set (f (R) = 1), the pump control and the motor control are not stopped or executed as described above.

On the other hand, if the result of the determination in step S70 is NO, that is, if it is not the reverse gear, step S71 is executed. In step S71, it is determined whether or not the flag f (R) remains set (f (R) = 1). Flag f
If (R) is 1 (YES), it means that the pump / motor control is prohibited after the reverse gear is released, and the process proceeds to step S72 where the vehicle speed V is substantially stopped, that is, the drive shaft 10 is stopped. , 12 is a predetermined value XV3 (for example, 0 km / h), which means that they are not rotating. Then, when the vehicle speed V is detected (V> XV3), the routine proceeds to step S75 described above, and the flag f (R) is kept set to the value 1, and the pump / motor control is kept in the prohibited state.
In this way, even though the gear position of the transmission 3 is not the reverse gear position in step S70,
When the vehicle speed V is detected at 72 (V> XV3), it is determined that the vehicle is moving backward, and the flag f (R) is set to the value 1 to ensure that the pump / motor control is prohibited. To do.

On the other hand, the vehicle speed V is determined by the determination in step S72.
Is not detected (V = XV3), step S
In step 73, the flag f (R) is reset to the value 0, and the pump / motor control prohibition state is released. When the speed is changed to a gear other than the reverse gear and the flag f (R) is reset to the value 0, the determination result in step S71 is also NO (negative) thereafter, and step S78 in FIG. 15 is executed. Become.

In step S78, the vehicle speed V is the predetermined value XV4.
(For example, 60 km / h) or more is determined. When the vehicle speed V is equal to or higher than the predetermined value XV4, it means an operating state in which the pump / motor control should be prohibited, and the process proceeds to step S90 of FIG. 16 described later, while when the vehicle speed V is lower than the predetermined value XV4, In step S80, the overspeed flag f (O
After determining whether or not / S) is the value 1, step S82
Proceed to. As will be described later, the overspeed flag f (O / S) is a program control variable for storing the dog clutch 51 when the vehicle speed V exceeds the predetermined value XV4 and the dog clutch 51 is disengaged. The overspeed flag f (O / S) has the value 0 in the case where it is immediately after the stage is released and the flag f (R) is reset to the value 0.

In step S82, it is determined whether or not the dog clutch connection / disconnection sensor (disconnection / connection SW) 92 outputs an ON signal. If the dog clutch 51 is not yet connected, the determination result of this step is negative (OFF), and the process proceeds to step S84. In step S84, the current vehicle speed V is determined, and if it is a predetermined value XV5 (for example, 5 km / h) or more, the process proceeds to step S88, and the dog clutch contact valve 5
3 and the valve shut-off 54, no drive signal is output (O
(FF), the diagnosis lamp 69 is also turned off (step S89), and the routine ends. That is, the vehicle speed V
Is greater than or equal to the predetermined value XV5, nothing is done with respect to the dog clutch 51.

If the vehicle speed V is smaller than the predetermined value XV5 and larger than 0 in the determination in step S84, the process proceeds to step S85, and the drive signal (ON signal) D is sent to the dog clutch contact valve 53.
8 is output to bring the dog clutch 51 into contact, and the routine ends. As a result, the dog clutch 51 is brought into the connected state, and in step S82 the dog clutch connecting / disconnecting S
When W92 is turned on, steps S88 and S89 described above are performed.
Is executed and the dog clutch valve 53 is turned off.

In the determination of step S84, the vehicle speed V is 0
If so, the process proceeds to step S86, and it is determined again whether the dog clutch connecting / disconnecting SW 92 outputs the ON signal,
If the ON signal is being output, the routine is terminated without doing anything, but if it is OFF, step S87.
To the drive signal (ON signal) to the dog clutch valve 53.
After D8 is output for 10 seconds, it is turned off for 10 seconds, and this is repeated as long as step S87 is repeatedly executed. When the vehicle is running at a low speed, the drive shaft 12 is rotating, so that the dog clutch 51 is likely to engage, but when the vehicle is stopped, the dog clutch 51 may be difficult to engage. Therefore, when the dog clutch 51 does not mesh even when the dog clutch contact valve 53 is turned on, the contact valve 53 is automatically turned on and off at intervals of 10 seconds to engage the dog clutch 51. When the dog clutch 51 is engaged, the ON signal of the dog clutch connecting / disconnecting SW 92 is detected in step S82, and then the process proceeds to step S88 to turn off the dog clutch contact valve 53.

After the dog clutch 51 is connected, the vehicle speed V
Is equal to or greater than the predetermined value XV4 (when the determination result in step S78 is affirmative (YES)), step S90 in FIG.
Is executed and it is determined whether or not the vehicle speed V is equal to or higher than a predetermined value XV4 continuously for a predetermined time (for example, one second). This discrimination prevents malfunction due to noise or the like. When the determination result of step S90 is NO (negative), that is, when the vehicle speed V is equal to or higher than the predetermined value XV4, but the predetermined time has not yet elapsed from the time when the vehicle speed V is first detected to be equal to or higher than the predetermined value XV4. Ends the routine without doing anything, but in the case of YES (affirmative), step S91
Drive signal (ON signal) to the dog clutch shutoff valve 54.
The dog clutch 51 is disengaged by outputting D8. Then, the dog clutch 51 is connected by the dog clutch connecting / disconnecting SW 92.
Is determined (step S92), and when the disconnection is not detected, a predetermined time (for example, 5 seconds)
(Step S94), and if the disengaged state of the dog clutch 51 is still not detected, the process proceeds to step S95 and the diagnosis lamp 69 is turned on (ON). As a result, when the dog clutch 51 cannot be disengaged despite the vehicle speed at which the dog clutch 51 should be disengaged,
The driver is warned of this condition.

When it is confirmed in step S92 that the dog clutch 51 has been disconnected by the dog clutch connecting / disconnecting SW 92, the process proceeds to step S96, in which the overspeed flag f (O / S) is set to a value of 1 and the high speed is set. The fact that the dog clutch 51 has been disconnected is stored. Then, the process proceeds to step S97, the output of the drive signal D8 to the dog clutch shutoff valve 54 is stopped (turned off), the diagnostic lamp 69 is turned off (step S98), and the routine ends.

As described above, when the vehicle is traveling at a high speed with the vehicle speed V, the pump / motor 40 is not operated by the pump or the motor, and the pump / motor 4 is rotated by the excessive rotation.
0 damage is prevented. When the overspeed flag f (O / S) is set to the value 1 by the high speed running and then the vehicle speed V decreases and the above-described step S80 is executed,
The determination result in that step is YES (affirmative), and the process proceeds to step S100 in FIG. In this step, it is determined whether or not the vehicle speed V has dropped below a predetermined value XV6.
The predetermined value XV6 is set to a value that allows smooth engagement even when the dog clutch 51 is brought into contact, for example, 5 km / h. If the vehicle speed V has not yet decreased to the predetermined value XV6 or less, the routine ends without doing anything. If the vehicle speed V has decreased below this value, step S10 is performed.
At 2, the overspeed flag f (O / S) is reset to the value 0 and the routine is finished. While the overspeed flag f (O / S) is set to the value 1, the steps after step S82 described above are not executed,
The dog clutch 51 is never operated. That is, if the vehicle speed V does not drop below the predetermined value XV6, the dog clutch 51 is not brought into contact with the vehicle, thereby preventing shock and clutch damage when the dog clutch 51 is engaged.

[0062]

As described above, according to the braking energy regenerating apparatus of the present invention, the reverse speed detecting means for detecting that the shift speed of the transmission of the vehicle is in the reverse speed, and the vehicle speed detecting for detecting the vehicle speed. Means and control means for controlling the operation of the hydraulic pump / motor according to the traveling state of the vehicle, and the control means stops the control of the hydraulic pump / motor when it detects that the shift speed is in the reverse gear. When the control is stopped, the control stop state is maintained until the vehicle speed becomes zero even if it is no longer detected that the shift speed is in the reverse speed. It is possible to avoid the situation where the hydraulic pump / motor is operated in the reverse rotation state, and it is possible to prevent the hydraulic pump / motor from being damaged or shock-vibrated due to an excessive load.

[Brief description of drawings]

FIG. 1 is a schematic diagram showing a configuration of a part of a braking energy regeneration device to which an embodiment of the present invention is applied and a vehicle equipped with the braking energy regeneration device.

FIG. 2 is a hydraulic circuit diagram showing a main configuration of a braking energy regeneration device of the present invention.

FIG. 3 is a block diagram showing a configuration of an electronic control unit (ECU) of the braking energy regeneration device of the present invention.

4 is a part of a flowchart of a pump control routine executed by the ECU 60 of FIG.

5 is a part of a flowchart of a pump control routine that follows the flowchart of FIG.

FIG. 6 is the rest of the flowchart of the pump control routine that follows the flowchart of FIG.

7 is a part of a flowchart of a motor control routine executed by the ECU 60 of FIG.

FIG. 8 is a part of a flowchart of a motor control routine following the flowchart of FIG.

9 is a part of a flowchart of a motor control routine that follows the flowchart of FIG.

10 is the rest of the flowchart of the motor control routine that follows the flowchart of FIG.

FIG. 11 is a graph showing an example of the relationship between the brake pressure PBK during pump control of the braking energy regeneration device and the tilt angle control signal value ELP set accordingly.

FIG. 12 is a graph showing an example of the relationship between the vehicle speed V and the discriminant value Xθ1 (accelerator opening degree) during motor control of the braking energy regeneration device.

FIG. 13 is a graph showing an example of a relationship between a vehicle speed V, an accelerator opening degree, and a tilt angle control signal value ELM corresponding to the vehicle speed V during motor control of the braking energy regeneration device.

FIG. 14 is a part of a flowchart of a dog clutch control routine according to the present invention.

15 is a part of a flowchart of a dog clutch control routine that follows the flowchart of FIG.

16 is a part of a flowchart of a dog clutch control routine that follows the flowchart of FIG.

17 is the rest of the flowchart of the dog clutch control routine that follows the flowchart of FIG.

[Explanation of symbols]

 1 Engine 2 Clutch 3 Transmission 10 Rear Wheel Drive Shaft 20 Accumulator 30 Low Pressure Hydraulic Oil Tank 40 Swash Plate Type Variable Capacity Piston Pump / Motor 41 Tilt Cylinder 42 Proportional Solenoid Valve 43 Pilot Hydraulic Source 50 Gearbox 51 Dog Clutch 60 Control Unit (ECU) 67 Governor control unit 70 Brake power unit 83 Vehicle speed sensor (vehicle speed detecting means) 84 T / M reverse sensor (reverse gear detecting means) 92 Dog clutch connection / disconnection sensor (connection / disconnection SW)

Claims (1)

[Claims] 1. A braking system for a hydraulic pump / motor connected to an oil passage between a low-pressure tank for storing hydraulic oil and an accumulator for storing hydraulic energy and connected to a vehicle drive system member via a clutch. At the time of pumping, the braking energy is converted into hydraulic energy and stored in the accumulator, while at the time of starting / accelerating, the motor is operated to utilize the hydraulic energy stored in the accumulator as starting / accelerating energy. The reverse gear detection means for detecting that the gear position of the transmission of the vehicle is in the reverse gear, the vehicle speed detection means for detecting the vehicle speed, and the control means for controlling the operation of the hydraulic pump / motor according to the running state of the vehicle. The control means stops the control of the hydraulic pump / motor when it detects that the shift speed is in the reverse speed, and When the control is stopped, the control stop state is maintained until the vehicle speed becomes substantially zero even if it is no longer detected that the shift stage is in the reverse stage. Braking energy regeneration device.