JP2885034B2 - Braking energy regeneration device - Google Patents

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 regenerating apparatus that uses a vehicle's braking energy for starting / acceleration energy using hydraulic oil as an energy transmission medium.

[0002]

2. Description of the Related Art Conventionally, a braking energy regenerating apparatus which is mounted on a vehicle such as a city bus and collects energy at the time of braking and uses it at the time of starting or accelerating is disclosed in, for example, Japanese Patent Publication No. 5-11.
No. 68 is known. This braking energy regenerating device operates a pump / motor as a pump during vehicle braking, pumps hydraulic oil from a low-pressure tank to an accumulator, and stores braking energy therein. When the vehicle starts or accelerates (these operations 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 and drive wheels of the vehicle. Is driven by a pump / motor, thereby reusing the braking energy.

[0003] Such a braking energy regenerating device can be separated from the driving wheels of the vehicle when the regenerating device does not need to be used or should not be used. A clutch (such as a dog clutch) is interposed between the device and the device.
When operating the braking energy regenerating device, the operating condition is that the clutch is in a connected state. When the regenerating device is activated, always check whether this condition is satisfied. ing. Then, the braking energy regenerating device is operated only when the clutch is in the connected state.

[0004]

In order to detect the engaged or disengaged state of the clutch, a clutch disconnection sensor (also referred to as a clutch disconnection switch) for electrically detecting ON and OFF is usually used. It is conceivable that the clutch connection / disconnection sensor causes a failure and outputs an erroneous signal. In such a case, a malfunction may occur such that the braking energy regenerating device is activated when it should not be activated, or does not operate when it is desired to be activated. In particular, if the clutch connection / disconnection sensor outputs an erroneous signal that the clutch connection / disconnection sensor is connected even though the clutch is actually in the disengaged state, the braking energy regenerating device operates normally and starts / accelerates energy. During the operation of the motor used for pumping, damage to the pump / motor or during the operation of the pump for recovering energy,
There is a possibility that the braking force generated by the operation of the pump does not work, causing insufficient braking force.

Accordingly, the present invention provides a braking energy regenerating apparatus which accurately checks the actual connection / disconnection state of a clutch to prevent damage to a pump / motor or a reduction in braking force. The purpose is to provide.

[0006]

In order to achieve the above-mentioned object, a braking energy regenerating device according to the present invention is provided in an oil passage between a low-pressure tank storing hydraulic oil and an accumulator storing hydraulic energy. A hydraulic pump / motor, which is connected to a drive system member of a vehicle via a clutch, is operated by a pump at the time of braking, and the braking energy is converted into hydraulic energy and stored in the accumulator, while the motor is operated at the time of starting / acceleration. A clutch operating means for connecting and disconnecting the clutch, a clutch connecting / disconnecting detecting means for detecting a connected / disconnected state of the clutch, and a vehicle speed for the braking energy regenerating device utilizing the hydraulic energy accumulated in the accumulator as start / acceleration energy. Vehicle speed detection means for detecting
Pump rotational speed detecting means for detecting the rotational speed of the hydraulic pump / motor; and control means for controlling the operation of the hydraulic pump / motor, wherein the control means determines that the clutch is in the engaged state by disengaging the clutch. Contact detection means, and only when the output of the vehicle speed detection means and the output of the pump speed detection means are in a predetermined proportional relationship,
The operation control of the hydraulic pump / motor is executed.

[0007]

The clutch connection / disconnection state is detected by the clutch connection / disconnection detecting means, and it is confirmed that the vehicle speed and the pump / motor speed are in a predetermined proportional relationship. Detected at the same time.

[0008]

An embodiment of the present invention will be described with reference to the drawings. The energy regenerating device shown in FIGS. 1 to 3 is applied to a vehicle including an engine 1 for driving driving wheels via a transmission 3 and a clutch 2, and includes a piston type accumulator 20, a low-pressure hydraulic oil tank 30, a swash plate type variable Capacity piston type pump / motor 40, gear box 5
0, a control unit 60 (hereinafter referred to as ECU) and the like.

First, the structure of a vehicle to which the energy regenerating 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 connected to the rear wheel drive shaft 10. It is connected to a differential (through shaft type). The energy regenerating device is connected to the above-described differential device via the drive shaft 12.

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

An accumulator 20 is connected to the high-pressure oil pipeline P1.
Shutoff valve 24 as a switching valve for accumulating and releasing hydraulic oil and unload valve (normally open) in order from the side
25 are provided. The shutoff valve 24 is an electromagnetic pilot operated valve, and normally functions as a check valve that allows the flow of hydraulic oil from the pump / motor 40 to the accumulator 20 and prevents the flow in the reverse direction. When the valve signal D2 is input, the flow of the hydraulic oil from the accumulator 20 to the pump / motor 40 is permitted. The electromagnetic unload valve 25 is activated by an unload valve signal D3 from the ECU 60, short-circuits the high-pressure oil line P1 and the low-pressure oil line P2 via the line P4, and stores the residual pressure trapped in the high-pressure oil line P1. To the low-pressure oil pipeline P2.

[0012] Between the high-pressure oil pipeline P1 and the low-pressure oil pipeline P2,
A check valve 46 is provided, and the check valve 46 is connected to the low-pressure oil pipe P.
2 allows the hydraulic oil to flow into the high-pressure oil pipeline P1, thereby preventing damage to the device caused by running out of hydraulic oil in the high-pressure oil pipeline P1. Further, a branch from the high-pressure oil pipeline P1 on the pump / motor 40 side from the shut-off valve 24 is connected to a pipeline P3 to the hydraulic oil tank 30. In this pipeline P3, the discharge pressure PHY of the pump / motor 40 is a predetermined pressure. A relief valve 26 is provided for releasing the high-pressure oil to the hydraulic oil tank 30 when the pressure exceeds 350 kgf / cm ² , for example.

The high-pressure oil pipe P1 is provided with a discharge pressure sensor 89 as a hydraulic sensor for detecting the pressure in the pipe on the pump / motor 40 side from the shut-off valve 24, and supplies a discharge pressure signal PHY to the ECU. I have. In the accumulator 20, a piston 21 is provided with a hydraulic oil chamber 2 by expansion of nitrogen gas.
The piston position sensor 87, which detects when it has moved to a predetermined position slightly before the maximum inflation position (referred to as the immediately preceding position) and outputs a piston position signal (off signal) LP.
And detects the operating oil pressure in the operating oil chamber 23 to store the accumulated pressure signal PAC.
Is provided, and supplies a piston position signal LP and a pressure accumulation signal PAC to the ECU 60, respectively.

The pump / motor 40 includes a gear box 50
Is connected to the drive shaft 12 described above, and the braking energy of the drive shaft 10 is transmitted between the drive shaft 12 and the gearbox 50.
Is transmitted to the pump / motor 40 via the
The starting / 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 includes a pair of gears 50 a and a dog clutch 51, and the pair of gears 50 a increases the rotation of the drive shaft 12 and transmits the rotation to the pump / motor 40.
The connection between the drive shaft 12 and the pump / motor 40 is disconnected and connected by a dog clutch 51.

The pump / motor 40 includes a gear box 50
Drive shaft 40e connected to the output shaft, a piston cylinder 40f rotating integrally therewith, a piston 40c fitted to the cylinder 40f, and a swash plate for reciprocating the piston 40c with the rotation of the drive shaft 40e. 40d, and the pump / motor displacement is set by controlling the angle of the swash plate 40d with respect to the drive shaft 40e, that is, the tilt angle.

The tilt angle of the swash plate 40d is
Is variably controlled. The tilt cylinder 41 includes a piston 41a connected to a swash plate 40d and a piston 4a.
Chambers 41b and 41 respectively formed on both sides of 1a
When a pilot oil pressure from a pilot oil pressure source 43 described later is supplied to one chamber, for example, the chamber 41b, the swash plate 40d is driven to the pump operation side, and the pilot oil pressure is supplied to the other chamber 41c. And the motor is driven to the operating side.

The pilot hydraulic pressure source 43 is composed of an oil pump or a pressure regulating valve driven by an electric motor or the like, 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 pressure source 43 and the tilt cylinder 41.
These are transmitted from the pilot hydraulic pressure source 43 to the tilt cylinder 41
And a pilot hydraulic control circuit for controlling the supply pressure of the pilot hydraulic pressure to the pilot hydraulic pressure. The switching valve 44 is connected to the ECU
60, the pilot signal P5
Communication and shut off.

When a control signal ELP is supplied to one of the solenoids of the proportional solenoid valve 42, for example, the solenoid 42a, a pilot oil pressure of a magnitude corresponding to the signal value ELP is applied via the proportional solenoid valve 42 to the pump operating side of the tilt cylinder 41. When the control signal ELM is supplied to the chamber 41b and the control signal ELM is supplied to the other solenoid 42b, a pilot oil pressure having a magnitude corresponding to the signal value ELM is applied to the chamber 41c on the motor operation side.
In this way, the operating position of the piston 41a of the tilt cylinder 41, and thus the tilt angle of the swash plate 40d, are variably controlled, and when the pump is operating, the discharge amount is adjusted. If so, the output torque is adjusted.

When the pump / motor 40 is operating,
The swash plate 40 d is driven to the pump operation side by the tilt cylinder 41, and the hydraulic oil is supplied from the hydraulic oil tank 30 to the filter 3.
8, flows through the check valve 58, the pipe P2, the pump / motor 40, and the pipe P1 to the accumulator 20, and at the time of motor operation, the swash plate 40d is driven to the motor operating side, and the operating oil is at the time of pump operation. In the opposite direction, from the accumulator 20, the pipe P1, the pump / motor 40, the pipe P2, the check valve 57,
It flows to the hydraulic oil tank 30 via the filter 37.

The hydraulic oil tank 30 is connected to a pressurized air tank 31 via an electromagnetic two-port switching valve 33, a pressure reducing valve 35, and an air dryer 36, and to an electromagnetic three-port switching valve 34.
Are connected to the sub-air tank 32 via the air tank, and these constitute an air pressure supply circuit to the hydraulic oil tank 30. The switching valve 34 is operated by a drive signal D7 from the ECU 60, and the sub air tank 32 and the hydraulic oil tank 30
Is switched to the position where the communication is established. Sub air tank 3
The sub-air tank 32 supplies the partially reserved air to the hydraulic oil tank 30 by communicating the hydraulic oil tank 2 with the hydraulic oil tank 30. Then, air is supplied or absorbed to stabilize the air pressure in the hydraulic oil tank 30. On the other hand, ECU 6
When the drive signal D7 from 0 is cut off, the switching valve 34 switches to the atmosphere release position, and releases the pressure in the hydraulic oil tank 30 to the atmosphere.

The switching valve 33 is actuated by a drive signal D6 from the ECU 60, supplies high-pressure air in the air tank 31 to the hydraulic oil tank 30, and pressurizes the hydraulic oil in the tank 30 to a predetermined pressure. / Keep the operation of the motor 40 stable. Hydraulic oil leaking from the pump / motor 40 or the fitting portion (oil seal) in the hydraulic path returns 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 to open the drive signal and to supply the insufficient hydraulic oil to the hydraulic oil tank 3.
Refill to zero.

The hydraulic oil tank 30 is provided with a hydraulic oil level sensor 90 and an oil temperature sensor 91, and supplies 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 the hydraulic oil is in a normal state and restricting the operation of the regenerative device, damage to devices such as the pump / motor 40 is prevented.

The dog clutch 51 is actuated by air pressure, and the dog clutch 51 has an electromagnetic three-port switching valve (dog clutch connecting valve) 53 for clutch connection and an electromagnetic three-port switching valve (clutch disconnecting valve) (clutch disengagement valve). The air tank 52 is connected via a dog clutch valve 54, and these constitute a dog clutch operation control circuit (clutch operating means). Switching valve 53 for clutch connection
Is activated 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, and the dog clutch 51 is engaged. On the other hand, when the clutch disconnection switching valve 54 is actuated by the drive signal D9 from the ECU 60, the dog clutch 51 is disengaged.

The dog clutch 51 is provided with a dog clutch connection / disconnection sensor (clutch connection / disconnection detecting means, also referred to as a dog clutch connection / disconnection SW) 92.
Is constituted by a limit switch, a reed switch, and the like, detects the connection / disconnection state of the dog clutch 51, and supplies a detection signal (on / off signal) DCL to the ECU 60.
A pump rotation speed sensor 93 for detecting the rotation speed of the pump / motor 40 is provided on the output shaft of the dog clutch 51 on the pump / motor 40 side.
P is supplied to the ECU 60. Pump speed sensor 9
For example, an encoder 3 including a slit disk and an optical element is used as 3. Since the pump / motor 40 is connected to the drive shaft 10 via the dog clutch 51, when the dog clutch 51 is in the connected state, the pump rotation speed is in a predetermined proportional relationship with the vehicle speed V, and increases in proportion to the vehicle speed V. It is supposed to.

A brake power unit 70 connected to a brake pedal (not shown) is for controlling the braking force of the driving wheel WR and the driven wheel WF, and a brake is applied to a wheel cylinder (not shown) of each wheel. Supplying air pressure. A brake pressure PBK generated according to the amount of depression of a brake pedal (not shown) is detected by a sensor (not shown), and a brake pressure detection signal PBK is supplied to the ECU 60. The ECU 60 is connected to the discharge pressure sensor 8 described above.
9, the discharge pressure PHY of the pump / motor 40 detected by
By comparing the magnitude of the brake pressure PBK with a predetermined value, the operation switching control between the pressure-accumulating brake by the pump operation of the pump / motor 40 and the normal service brake is performed.

The engine 1 is provided with a fuel injection device 5. A governor control unit 67 connected to the fuel injection device 5 performs a normal fuel injection control and a rack limit signal R from an ECU 60 described later. Fuel limit (rack limit). The fuel injection limit (rack limit) is set so that the sum of the output from the motor operation of the pump / motor 40 and the output from the engine 1 does not exceed the output corresponding to the maximum driving torque of the normal engine 1 alone. The control is performed. The governor control unit 67 detects the engine speed NE and outputs the engine speed signal NE as E.
Supply to CU60.

The transmission 3 is provided with a vehicle speed sensor 83 for detecting the vehicle speed from the rotation speed of its output shaft, a T / M reverse sensor 84, a T / M neutral sensor 85, and a select position sensor 86 for detecting the gear position. And the vehicle speed signal V and the T / M reverse signal TM, respectively.
The R, T / M neutral signal TMN and the select position signal LTM are supplied to the ECU 60. Vehicle speed sensor 83
For example, one that detects a protrusion of a disk attached to an output shaft with a pickup coil is used.

FIG. 3 shows a configuration of the ECU 60 for controlling the operation of the energy regenerating device. The ECU 60 includes a processor, a memory, an input / output circuit, and the like. This ECU 6
On the input side of 0, a main SW 64 for supplying a power ON / OFF state signal and an accelerator pedal (not shown) are linked,
An accelerator opening sensor 61 for detecting the depression amount of the accelerator pedal, and two clutch sensors (CL) for detecting the connection and disconnection of the engine clutch in conjunction with a clutch pedal (not shown)
1) 62, (CL2) 63, and various sensors including the above-described brake pressure sensor are connected. Here, the engine clutch connection / disconnection sensor (CL1) 62 is set so as to be turned ON by supplying a signal at a return limit (clutch connection) of a clutch pedal (not shown). ) 63 is set so as to be turned ON by supplying a signal at a stepping limit (clutch disengagement) of a clutch pedal (not shown), and a half clutch is provided by a combination of the sensor (CL1) 62 and the sensor (CL2) 63. The state can be detected.

On the other hand, the output side of the ECU 60 is connected to the various electromagnetic switching valves and various indicators described above. Indicators include a pressure accumulating indicator 66 that indicates the amount of accumulated pressure by a piston position signal LP from a piston sensor 87 of the accumulator 20 and an accumulated pressure signal PAC from an accumulator sensor 88, and a dog clutch connection / disconnection signal DCL from a dog clutch connection / disconnection sensor 92. , A dog clutch 51 is connected and a regenerative lamp 68 for displaying that the energy regenerating apparatus is operating and a diagnostic lamp 69 for displaying an error by various error signals.

Hereinafter, pump control and motor control of the braking energy regenerating apparatus configured as described above will be described with reference to flowcharts shown in FIGS. FIG.
FIGS. 5 and 6 show a control procedure of the pump control performed by the ECU 60 during braking. First, in step S10, the ECU 60 determines whether the dog clutch connection / disconnection flag f
(C / L) causes dog clutch 51 to be ON (connected) or OF
F (cut) is determined. When the vehicle is in a predetermined driving state (for example, when the vehicle speed is 5 km / h or less and the vehicle is running at a select position other than the reverse gear position), the dog clutch 51 switches the clutch connection switching valve 53 from the ECU 60.
The drive signal D8 is supplied to the motor and turned ON (connected). When the vehicle speed is equal to or higher than a predetermined vehicle speed (for example, 60 km / h), the drive signal D9 is supplied to the disconnection switching valve 54 in order to prevent the pump / motor 40 from being damaged. It is supplied and turned off (cut). When the dog clutch 51 is connected, the pump / motor 40
Are driven by the drive wheels WR via the drive shafts 10, 12 and the gear box 50.

If the result of the determination in step S10 is OFF (disconnection), the flow proceeds to step S20 in 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 cut-off state, and the piston 41a of the tilt angle cylinder 41 is also held at the neutral position. By maintaining 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,
In step S22, the unload valve signal D3 is not output to the unload valve (normally open) 25, but is turned off (open), and the high-pressure oil line P1 and the low-pressure oil line P2 is kept in communication. In step S23, the ECU 60 sets a value 0 (f1 = 0) to a flag f1, which is a program control variable,
Thus, the fact that the pump control is not performed is stored.

Returning to step S10 of FIG. 4, if the result of the determination in this step is ON (connected), the flow proceeds to step S11. The dog clutch connection / disconnection flag f described later
If the dog clutch 51 or the dog clutch connection / disconnection sensor 92 is detected to be abnormal by (C / L), step S
The determination result of 10 is OFF (disconnected), and the pump control is not executed in this case as well. In step S11, the ECU 60 determines whether or not the selected position of the transmission 3 is in the reverse gear (reverse position) by using the T / M reverse signal TMR, and the determination result is YES.
(Reverse), that is, if the vehicle is in the reverse gear position, the above-described step S20 and subsequent steps in FIG. 6 are executed, and the pump control is not performed. On the other hand, if the determination result is NO, that is, if the vehicle is in the forward gear position, step S12 is executed.

In step S12, the ECU 60 determines whether the vehicle has stopped. This determination is based on the vehicle speed V
Is less than or equal to a predetermined value XV0 (for example, 1 km / h) based on the vehicle speed signal V, and if V ≦ XV0 (1 km / h), the pump control is not executed. On the other hand, if the determination result is V> XV0 (1 km
If / h), step S13 is executed. Step S1
In step 3, the ECU 60 determines whether or not the driver has depressed the brake pedal (not shown) to generate the brake pressure PBK by the brake pressure signal P from the brake pressure sensor.
Determined by BK, PBK <XPB (for example, 0.2 kgf / cm
^{In the 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 result of the determination is PBK ≧ XPB (0.2 kgf / cm ² ), it is determined that all the operating conditions for regenerating energy have been satisfied,
Step S14 is executed.

In step S14, the ECU 60 determines the tilt angle control signal value ELP of the swash plate 40d of the pump / motor 40.
Is executed. As a method for setting the ELP value, for example, as shown in FIG.
A reference value corresponding to BK is calculated, and this reference value is further added to the oil temperature TOI detected by the oil temperature sensor 91 of the hydraulic oil tank 30.
L, the vehicle speed V detected by the vehicle speed sensor 83, the accumulated pressure PAC of the accumulator 20, etc. are corrected and set to appropriate values.

In step S15, the ECU 60 outputs a control signal corresponding to the ELP value set as described above to the proportional solenoid valve 42, and changes the tilt angle of the pump / motor 40 to an angle corresponding to the signal value ELP. Set. Next, in step S16, a drive signal D1 is output to the switching valve 44,
This is turned ON (open), and 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 by the unload valve signal D3.
(Closed) and shut off so that the pressure in the high-pressure oil pipeline P1 does not escape to the low-pressure oil pipeline P2. Further, in step S18, a flag f is stored to store that the pump is operating.
Set the value 1 to 1.

When the tilt angle of the pump / motor 40 is set to an 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 Hydraulic oil 30 is sucked and pushed into the hydraulic oil chamber 23 of the accumulator 20 to accumulate pressure. In the pump control described above, the tilt angle of the pump / motor 40 is set according to the driver's brake pedal depression amount, and the pump / motor 40 performs a work corresponding to the brake pedal depression amount and performs braking. Energy will be recovered.

FIGS. 7 to 10 show a control procedure of motor control at the time of starting and accelerating (at the time of starting / acceleration). First, E
Before starting the motor operation, the CU 60 determines whether or not to execute the motor control 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 result of the determination in step S30 is PBK ≧ XPB (0.2 kgf / cm ² ), step S50 and subsequent steps in FIG. 10 to be described later are executed, and the motor control is not performed. On the other hand, if the discrimination result is PBK <XPB (0.2 kgf / cm
^{If 2} ), go to step S31.

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

In step S32, the ECU 60 sets the dog clutch 51 based on the dog clutch connection / disconnection flag f (C / L).
Is ON (connected) or OFF (disconnected)
If it is (cut), the motor control is not executed. On the other hand, if the determination result is ON (connection), the process proceeds to step S33.
As described in the pump control, the dog clutch 51 is controlled by the dog clutch connection / disconnection flag f (C / L) described later.
When the abnormality of the dog clutch connection / disconnection sensor 92 is detected, the determination result in step S32 is OFF (disconnected), and the motor control is not performed in this case as well.

In step S33, the ECU 60 determines whether or not the selected position of the transmission 3 is at the reverse gear (reverse position) by using the T / M reverse signal TMR. If the gear is in the reverse gear position, the motor control is not executed. on the other hand,
If the determined result is NO, that is, if the vehicle is in the forward gear position, the process proceeds to step S34.

In step S34, the ECU 60 determines whether or not the selected position of the transmission 3 is in neutral, based on the T / M neutral signal TMN.
If the determination result is YES (neutral), that is, if the selected position is neutral, it is determined that the driver does not intend to start the vehicle yet, and the motor control is not performed. On the other hand, when the result of the determination is NO, the process proceeds to step S35.

In step S35, the ECU 60 determines whether the clutch 2 is connected or disconnected based on the clutch connection / disconnection signal CL2 of the clutch connection / disconnection sensor (CL2) 63. No motor control is performed as in the case where is neutral. On the other hand, if it is 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 or not the accumulator 20 is filled with hydraulic oil.
The determination is made based on the piston position signal LP from the piston position sensor 87. When the piston position sensor 87 set at the immediately preceding position of the piston 21 is 0FF, that is, when the hydraulic oil is empty, the hydraulic oil is not accumulated in the accumulator 20, and 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 the working oil, the process proceeds to step S37.

In step S37, the ECU 60 determines whether or not the vehicle speed V is equal to or lower than a predetermined value XV2 (for example, 65 km / h) based on the vehicle speed signal V. If the vehicle speed V 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 equal to or less than 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 a predetermined value XV1 (for example, 5 km) as in step S37.
/ h), if the value is smaller than the XV1 value, step S3
9 to determine whether the clutch 2 is completely connected or in a half-clutch state.
The determination is made based on the clutch connection / disconnection signal CL1. By the determination in step S38, the vehicle speed V becomes the predetermined value XV1 (5 km / h).
If it is determined that the clutch 2 is completely connected in spite of being smaller, it is determined that there is some abnormality in the clutch sensors 62 and 63, the vehicle speed sensor 83, etc. No motor control is performed. On the other hand, when the clutch connection / disconnection signal CL1 indicates the OFF state, the clutch 2
Means a half-clutch state, and in such a case, the process proceeds to step S40.

In step S40, the ECU 60 determines whether or not the accelerator opening L Aθ is greater than the motor start opening determination value Xθ1 based on the accelerator opening signal L Aθ. The above-described determination value Xθ1 is set according to the vehicle speed V,
FIG. 13 shows the vehicle speed V and the discrimination value X set thereby.
The relationship with θ1 is shown. If the accelerator opening LAθ is smaller than the discrimination value Xθ1 (LAθ <Xθ1), it is determined that the vehicle is not in a state to be accelerated, and the motor is not operated. On the other hand, it is larger than the discrimination value Xθ1 (LAθ ≧ Xθ1
), The process proceeds to step S41 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 to 2 is set to zero (ELM = 0) and output. Thereby, the tilt angle cylinder 4
The first piston 41a is held at 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
a switching valve 44 for controlling the supply and discharge of pilot oil for driving a
Is turned off (closed) by rejecting the drive signal D1. In step S52, the shut-off valve 24 that is ON (open) when the motor is operated is turned off (closed) by cutting off the shut-off 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 disposed between the low-pressure oil pipeline P2 and the high-pressure oil pipeline P1 stops outputting the unload valve signal D3, and is turned off (open). And low pressure oil pipeline P
Let 2 communicate. In step S54, a rack limit signal R, which will be described later, transmitted to the engine 1 when the motor is operated is turned off by turning off, and in step S55, the rack limit enable signal RE, which is also transmitted, is turned off and OF is turned off.
F. Finally, in step S56, a value 0 (f2 = 0) is set in a flag f2, which is a program control variable, to store that the motor control is not performed.

On the other hand, when the motor control is started by executing step S41, the ECU 60 sets the pump / motor 4
A subroutine for setting the tilt angle control signal value ELM of the zero swash plate 40d is executed. As a method of setting the ELM value,
First, a reference value is set according to the accelerator opening LAθ and the vehicle speed V (the engine speed NE may be used instead of the vehicle speed V). FIG. 14 shows an ELM map stored in the storage device of the ECU 60. The ECU 60 reads out ELM reference values (XM0, XM1,...) Corresponding to the vehicle speed V and the accelerator opening LAθ from this map. Next, a correction coefficient K2 corresponding to the oil temperature of the hydraulic oil tank 30 detected by the oil temperature sensor 91 is obtained, and the correction coefficient K2 is multiplied by the ELM reference value.
Optimum tilt angle control signal ELM value (= ELM reference value × K2)
) Is calculated. Changing the tilt angle control signal value ELM according to the accelerator opening L Aθ is equivalent to changing the pump / motor control so that a response similar to the accelerator operation response at the time of starting and accelerating only by the normal engine 1 is obtained.
This is to change the output torque value due to the operation of the motor 40. Also, the vehicle speed V (or the engine speed NE)
) To change the tilt angle control signal value ELM to effectively use regenerative energy in a low-speed region such as starting, thereby preventing the generation of black smoke.

The correction based on the oil temperature of the hydraulic oil tank 30 does not require correction of the ELM value if the oil temperature is lower than 70 ° C., for example, but the tilt angle control signal value ELM if the oil temperature is 70 ° C. or higher.
Is corrected to reduce. At a high temperature, the viscosity of the hydraulic oil decreases, and there is a risk of seizure of the pump / motor 40. This is prevented by reducing the motor capacity.

Next, the ECU 60 executes step S4 in FIG.
In step 2, a control signal corresponding to the ELM value set as described above is output to the proportional solenoid valve 42, and step S4
At 3, the drive signal D1 is output and the switching valve 44 is turned on.
(Open) and the tilt angle cylinder 4
1 is supplied with pilot hydraulic pressure. 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
And outputs the shut-off valve signal D2 to ON (open), and supplies the unload valve signal D3 to the unload valve (normally open) 25 in step S45 to turn it ON (closed). Then, 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 high-pressure hydraulic oil stored in the accumulator 20, and its driving force is transmitted to the driving wheels WR via the driving shaft 40e, the gear box 50, the driving shafts 12, 10, and when the vehicle starts moving. And part of the driving force during acceleration.

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 is used to limit the output torque of the engine 1 during motor control.
It is determined based on the engine speed NE and the accumulated pressure PAC of the accumulator 20. Then, in order to reliably execute the output restriction on the engine 1 side supplied to the fuel injection device 5, in step S47, a rack restriction enable signal RE is output to the governor control unit 67 to prevent malfunction due to noise or the like. doing. Finally, step S
At 48, a value of 1 is set to a flag f2, which is a program control variable, thereby storing that the motor is operating.

FIG. 11 shows a dog clutch connection confirmation control procedure according to the present invention. The ECU 60 repeatedly executes this confirmation control program at a predetermined cycle to constantly monitor the connection state of the dog clutch 51.
By performing this monitoring control, the pump / motor 40 may be damaged when the dog clutch connection / disconnection sensor (dog clutch connection / disconnection SW) 92 outputs an ON (connection) signal even though the dog clutch 51 is not connected. Various troubles can be prevented.

First, in step S70, it is determined whether the dog clutch connection / disconnection sensor 92 is ON or OFF. If the determination result is OFF, the pump / motor operation control is not performed, so in step S80, a value 0 is set in the disconnection / connection flag f (C / L) of the dog clutch 51, and this is stored, and the next step S81 In order to inform the driver that the pump / motor control is not executed, the regenerative lamp 68
(FIG. 3) is turned off (OFF), and the routine ends. When the flag f (C / L) is reset (value 0), neither the pump control nor the motor control is executed as described above.

On the other hand, the connection of the dog clutch 51 is detected by the dog clutch connection / disconnection sensor 92, and the process proceeds to step S70.
If the determination result is ON, the flow advances to the next step S71 to determine whether or not the dog clutch connection / disconnection flag f (C / L) has a value of 1. By executing the routine, the connection of the dog clutch 51 is confirmed once, and when the value f is set to 1 in the flag f (C / L), it is not necessary to confirm the connection of the dog clutch 51 thereafter. The process proceeds to step S73 described below. Then, the determination result is NO (f (C / L) =
If the connection of the dog clutch 51 has not been confirmed yet in 0), the process proceeds to the next step S72 to confirm the dog clutch connection.

Step S72 is a step for confirming the dog clutch connection. The vehicle speed signal V from the vehicle speed sensor 83 and the pump speed sensor 93 determine whether or not the vehicle speed V and the pump speed NP are in a predetermined proportional relationship. The comparison is made with the pump rotation speed signal NP. This determination is performed, for example, by comparing the frequencies of the respective signals. If both frequencies have a certain proportional relationship, and if the error is within a predetermined range (for example, ± 10 to 20%), it is assumed that the dog clutch is connected. It is to be. If the determination result is NO and the proportional relationship between the vehicle speed V and the pump speed NP cannot be confirmed, the aforementioned step S8 is performed.
At 0, the flag f (C / L) is kept at the value 0, and step S81
, The regenerative lamp 68 is turned off (OFF), and the execution of the pump control or the motor control is prohibited. By this prohibition command, no pump control or motor control is performed.

On the other hand, if the decision result in the step S72 is YES.
If the dog clutch connection can be confirmed, then step S
Proceeding to 73, a value 1 is set to the flag f (C / L), and in step S74, the regeneration lamp 68 is turned on (ON) to indicate that the energy regeneration control is being executed. As a result, the operation of the dog clutch 51 and the dog clutch connection / disconnection sensor 92 are consistent, and pump control or motor control may be performed. By the way, if the result of the determination in the previous step S71 is YE
In the case of S, that is, once the connection confirmation of the dog clutch 51 is obtained, the process proceeds to step S73 without executing step S72 again, and sets the flag f (C / L) to the value 1
And the regenerative lamp 68 is turned on in step S74 (O
N) While maintaining the state, the execution of the pump control or the motor control is continued.

[0057]

As described above, according to the braking energy regenerating device of the present invention, the clutch connection state is detected by the clutch connection / disconnection detecting means for detecting the clutch connection / disconnection state, and the vehicle speed is detected. The operation control of the pump / motor is executed only when the output of the means and the output of the pump speed detecting means are in a predetermined proportional relationship. It is possible to prevent damage to the pump / motor or insufficient braking force due to a malfunction.

[Brief description of the drawings]

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

FIG. 4 is a part of a flowchart of a pump control routine executed by an ECU 60 in FIG. 3;

FIG. 5 is a part of a flowchart of a pump control routine that follows the flowchart of FIG. 4;

FIG. 6 is the remaining part of the flowchart of the pump control routine following the flowchart of FIG. 4;

FIG. 7 is a part of a flowchart of a motor control routine executed by an ECU 60 in FIG. 3;

FIG. 8 is a part of a flowchart of a motor control routine following the flowchart of FIG. 7;

FIG. 9 is a part of a flowchart of a motor control routine that follows the flowchart of FIG. 8;

FIG. 10 is the remainder of the flowchart of the motor control routine that follows the flowchart of FIG. 8;

FIG. 11 is a flowchart of a dog clutch connection confirmation control routine of the braking energy regeneration device according to the present invention.

FIG. 12 is a graph showing an example of a relationship between a brake pressure PBK at the time of pump control of the braking energy regeneration device and an ELP value set according to the brake pressure PBK.

FIG. 13 is a graph showing an example of a relationship between a vehicle speed V and a discrimination value Xθ1 (accelerator start opening degree) at the time of motor control of the braking energy regeneration device.

FIG. 14 is a graph showing an example of a relationship between a vehicle speed V, an accelerator opening, and a tilt angle control signal value ELM corresponding to the vehicle speed V and the accelerator opening during motor control of the braking energy regeneration device.

[Description of Signs] 1 Engine 2 Clutch 3 Transmission 10 Rear wheel drive shaft 20 Accumulator 24 Shutoff valve 26 Relief valve 30 Low pressure hydraulic oil tank 40 Swash plate type variable displacement piston pump / motor 41 Tilting cylinder 42 Proportional solenoid valve 43 Pilot hydraulic power source Reference Signs List 50 Gear box 51 Dog clutch 52 Air tank (clutch operating means) 53 Dog clutch connecting valve (clutch operating means) 54 Dog clutch disconnecting (clutch operating means) 60 Control unit (ECU) 68 Regenerative lamp 83 Vehicle speed sensor (vehicle speed detecting means) 92 Dog clutch disconnecting Contact sensor (clutch disconnection detecting means) 93 Pump rotation speed sensor (pump rotation speed detecting means)

Claims (1)

(57) [Claims] 1. A hydraulic pump / motor, which is interposed in an oil passage between a low-pressure tank for storing hydraulic oil and an accumulator for accumulating hydraulic energy and is connected to a drive system member of a vehicle via a clutch, is provided with a brake. In a braking energy regenerating device, a pump is operated at times to convert braking energy into hydraulic energy and accumulates the energy in the accumulator, while a motor is activated during start / acceleration, and the hydraulic energy accumulated in the accumulator is used as start / acceleration energy. Clutch operating means for disconnecting and driving the clutch, clutch disengagement detecting means for detecting the disengaged state of the clutch,
Vehicle speed detecting means for detecting a vehicle speed; pump rotational speed detecting means for detecting the rotational speed of the hydraulic pump / motor; and control means for controlling the operation of the hydraulic pump / motor.
The control means is provided only when the clutch engagement state is detected by the clutch connection / disconnection detection means, and when the output of the vehicle speed detection means and the output of the pump speed detection means are in a predetermined proportional relationship. And a brake energy regenerating device for controlling the operation of the hydraulic pump / motor.