JP2885031B2 - 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] Motor operation of a vehicle equipped with such a braking energy regenerating device is controlled by operating an accelerator pedal. The detected value (accelerator voltage) from the accelerator opening sensor (accelerator pedal operation amount detecting means) and the actual depression amount of the accelerator pedal (accelerator opening) are related, and the hydraulic pump / The output torque (motor output) of the motor is adjusted. Here, the control unit stores the accelerator voltage value in a state where the accelerator pedal is turned off and the operation amount becomes zero (during idling) as a reference value of the accelerator opening (the accelerator opening is zero). This is the control base point for control.

[0004]

While the vehicle is running, for example, even if the driver does not press the accelerator pedal, the driver may not detect the accelerator opening degree sensor or the accelerator pedal may return. In some cases, the state may be the same as when the accelerator pedal is operated. Conventionally, in such a case, although the accelerator opening is actually zero, an accelerator voltage larger than a predetermined voltage value when the accelerator opening is zero may be supplied to the control unit (ECU). However, in this case, the control unit may determine that the vehicle is in the start / acceleration state in which the accelerator pedal is operated, and may start the motor control.

SUMMARY OF THE INVENTION It is an object of the present invention to provide a braking energy regenerating apparatus capable of always accurately detecting an operation amount of an accelerator pedal and executing motor control according to an actual accelerator opening. .

[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. In a braking energy regenerating device that uses hydraulic energy accumulated in an accumulator as start / acceleration energy, an accelerator operation amount detecting means for detecting an operation amount of an accelerator pedal, and a detection detected from the accelerator operation amount detecting means at the time of vehicle braking. While storing the zero point correction value of the operation amount of the accelerator pedal based on the value,
At the time of start / acceleration of the vehicle, control for correcting the operation amount detection value of the accelerator pedal based on the stored zero point correction value and controlling the motor output torque of the pump / motor in accordance with the corrected operation amount of the accelerator pedal. Means.

[0007]

[Function] At the time of vehicle braking (when recovering energy by pump control), the driver surely releases his / her foot from the accelerator pedal.
Each time, the accelerator voltage value is regarded as zero for the accelerator opening, and this is stored as a zero-point correction value of the accelerator pedal, thereby enabling accurate motor control according to the actual accelerator opening.

[0008]

An embodiment of the present invention will be described with reference to the drawings. The energy regenerating 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 includes 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
U).

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.
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 hydraulic oil from the pump / motor 40 to the accumulator 20 and prevents the flow in the reverse direction.
When the shutoff valve signal D2 from 60 is input, the flow of 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 line P3 branches off from the high-pressure oil pipe P1 on the pump / motor 40 side from the shut-off valve 24 and is connected to the hydraulic oil tank 30, and the discharge pressure of the pump / motor 40 is set at the set pressure ( For example, 3
When the pressure exceeds 50 kgf / cm ² ), a relief valve 26 is provided for releasing the high-pressure oil to the hydraulic oil tank 30.

The high-pressure oil pipe P1 is provided with a discharge pressure sensor 89 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. The accumulator 20 detects when the piston 21 has moved 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, and detects the piston position signal (off signal). LP
And a pressure accumulating sensor 88 for detecting the operating oil pressure in the hydraulic oil chamber 23 and outputting a pressure accumulating signal PAC, respectively.
P and a pressure accumulation signal PAC are supplied to the ECU 60.

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 50a and a dog clutch 51. The pair of gears 50a increases the speed of rotation of the drive shaft 12 at a constant gear ratio, and the pump / motor 4
Transmit to 0. 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.
Thus, the operating position of the piston 41a of the tilt cylinder 41 and the tilt angle of the swash plate 40d are variably controlled.

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 the device due to seizure of the pump / motor 40 or the like is prevented.

The dog clutch 51 is actuated by the air pressure. The dog clutch 51 is connected to an air tank 52 via an electromagnetic three-port switching valve 53 for clutch connection and an electromagnetic three-port switching valve 54 for disconnecting the clutch. Are connected, and these constitute a dog clutch operation control circuit. The switching valve 53 for clutch connection is provided by the ECU 6
When activated by the drive signal D8 from 0, the air tank 5
The high-pressure air of 2 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 92, which detects the connection / disconnection state of the dog clutch 51 and supplies a detection signal DCL to the ECU 60. A rotation speed sensor 93 for detecting the rotation speed of the pump / motor 40 is provided on the pump / motor side output shaft of the dog clutch 51, and supplies a pump rotation speed signal NP to the ECU 60.

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 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. Further, the governor control unit 67 has an engine speed detecting means, and the engine speed NE
And an engine speed signal NE is supplied to the ECU 60.

The transmission 3 has a vehicle speed sensor 8
3, a T / M reverse sensor 84, a T / M neutral sensor 85, and a select position sensor 86 are provided, and a vehicle speed signal V, a T / M reverse signal TMR,
The T / M neutral signal TMN and the select position signal LTM are supplied to the ECU 60. FIG. 3 shows a configuration of the ECU 60 for controlling the operation of the energy regenerating apparatus.
The U60 includes a processor, a memory, an input / output circuit, and the like. On the input side of the ECU 60, a main SW 64 for supplying a power ON / OFF state signal, an accelerator opening degree sensor (accelerator operation amount detecting means) 6 for detecting an accelerator pedal depression amount in conjunction with an accelerator pedal (not shown) 6
1. Two clutch sensors (CL1) that detect the connection and disconnection of the engine clutch in conjunction with a clutch pedal (not shown)
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 above-mentioned various electromagnetic switching valves and various indicators are connected to the output side of the ECU 60. Indicators include a piston position signal LP from a piston sensor 87 of the accumulator and a pressure accumulation sensor 88.
An accumulator indicator 66 for indicating the amount of accumulated pressure in accordance with the accumulated pressure signal PAC from the CPU, a regenerative lamp 68 for indicating that the energy regenerator is in operation by the dog clutch connection / disconnection signal DCL from the dog clutch connection / disconnection sensor 92, and various errors (abnormalities) There is a diagnostic lamp 69 which indicates an error by a signal.

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.
5 and 6 show a control procedure of the pump control performed by the ECU 60 during braking. First, the ECU 60 turns on the dog clutch 51 in response to the dog clutch connection / disconnection signal DCL from the dog clutch connection / disconnection sensor 92 in step S10.
(Connection) or OFF (Disconnection) is determined. Note that the dog clutch 51 is provided when the vehicle is in a predetermined driving state (for example, when the vehicle speed is 5).
The driving signal D8 is supplied from the ECU 60 to the clutch connection switching valve 53 to be ON (connected) when the vehicle is traveling at a selected position other than the reverse gear at km / h or less).
In order to prevent damage to the pump / motor 40 at a predetermined vehicle speed (for example, 60 km / h) or higher, the disconnection switching valve 5
4 is supplied with the drive signal D9 and turned off (disconnected).
When the dog clutch 51 is engaged, the pump / motor 40 is 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 (cut), 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. For example, if an abnormality of the regenerative device is detected and the dog clutch 51 is disengaged, step S20 and subsequent steps are executed according to the judgment of step S10, and the pump control is not executed.

Returning to step S10 in FIG. 4, if the determination result in this step is ON (connection), the process proceeds to step S11. In step S11, the ECU 60 determines whether or not the selected position of the transmission 3 is in the reverse gear position (reverse position) by the T / M reverse signal TMR, and the determination result is YES (reverse), that is, the vehicle reverse gear position. If it is a position, the above-described step S20 in FIG.
Execute the following and do not perform pump control. On the other hand, if the determination result is NO, that is, if the vehicle is in the forward gear position, step S1 is executed.
Execute Step 2.

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 referred to as an oil temperature TOIL detected by an oil temperature sensor 91 of the hydraulic oil tank,
Vehicle speed V detected by vehicle speed sensor 83, accumulator 2
It is corrected by the accumulated pressure amount PAC of 0 or the like and set to an appropriate value.

In step S15 of FIG.
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 an angle corresponding to the signal value ELP. Next, in step S16, a drive signal D1 is output to the switching valve 44 to turn it on (open), and the tilt angle cylinder 41
Supply pilot hydraulic pressure to In step S17, the unload valve (normally open) 25 between the low-pressure oil pipe P2 and the high-pressure oil pipe P1 is turned on (closed) by the unload valve signal D3, and the pressure of the high-pressure oil pipe P1 is changed to the low-pressure oil pipe P2. Cut off so as not to escape. Further, step S
At 18, the value 1 is set to the flag f1 to store that the pump is operating.

As described above, 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 30 And presses it into the hydraulic oil chamber 23 of the accumulator 20 to accumulate the pressure. Step S19 is a step of checking the idle accelerator voltage according to the present invention, and executes a subroutine shown in FIG. The check of the idle accelerator voltage value XAE is performed by the ECU 60 when the driver releases his / her foot from the accelerator pedal and the accelerator pedal does not return for some reason or when there is a detection error of the accelerator opening sensor 61 or the like. However, this is performed in order to prevent an erroneous determination that motor control to be described later should be executed and to execute appropriate motor control. Step S7
In the case of 0, first, it is determined whether or not the pump control is being performed in the sense of confirmation based on whether or not the value of the flag f1 is 1. The determination result is NO
In this case, since the pump control is not being performed, the routine is not executed. On the other hand, if the determination result is YES, the driver releases his / her foot from the accelerator pedal to start a braking operation (pump control), determines that the vehicle is idling, proceeds to step S72, and proceeds to step S72, where the idle accelerator voltage value ( The execution of a check routine of (zero point correction value) XAE is started.

In step S72, the currently detected accelerator voltage value E becomes the standard value E0 (for example, 1.0 V).
It is determined whether or not this is the case. If it is determined that the detected accelerator voltage value E is smaller than E0 (E <E0), the idling accelerator voltage value (zero-point correction value) is determined in step S76.
XAE is set to the standard value E0, and this is stored in the storage device. This is to prevent the ECU 60 from becoming difficult to determine due to noise or the like when the accelerator voltage value E becomes too small. On the other hand, in the determination of step S72,
If the accelerator voltage value E is equal to or greater than the standard value E0 (E ≧ E0
Then, step S74 is executed.

In step S74, the detected accelerator voltage value E is newly stored as an idle accelerator voltage value XAE (XAE = E), and is replaced with the stored value obtained when the previous routine was executed. FIG. 12 shows the relationship between the accelerator voltage value E and the accelerator opening L Aθ, and the broken line (basic line) in the figure indicates the relationship when the idle accelerator voltage value is E0 (LA θ = K × (E−E0)). ) And the above-described step S
When step 76 is executed, the accelerator opening (accelerator pedal operation amount) is detected along the basic line. On the other hand, the solid line (correction line) in FIG.
Is executed, the accelerator voltage value E is newly reset as the idle accelerator voltage value XAE (LAθ).
= K × (E−XAE)), in this case, the detected value LAθ is shifted (parallel movement) as a whole by the difference between the reset idle accelerator voltage value XAE and the previous voltage value XAE ′. Will do.

By executing step S74, the accelerator voltage value E when the driver releases his / her foot from the accelerator pedal is set to the idle accelerator voltage value XAE at which the accelerator opening L Aθ is zero. Even when the accelerator pedal does not return to normal or the accelerator opening sensor outputs a value greater than the standard value E0 due to detection failure, the accelerator voltage value E output at that time is output.
Becomes the new idle accelerator voltage value XAE.
It is avoided that the motor control is started due to the erroneous determination of U60. This check routine is repeatedly executed every time the braking is performed and the pump control is executed, and the idle accelerator voltage value XAE is constantly monitored to ensure the safe running of the vehicle.

In the above pump control, the tilt angle of the pump / motor 40 is set according to the driver's depression amount of the brake pedal or the like. To recover the braking energy. Also, the idle accelerator voltage value X
By monitoring and correcting the AE, it prepares for accurate motor control.

FIGS. 7 to 10 show control procedures for motor control during starting and acceleration (start / 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 determines whether the dog clutch connection / disconnection sensor 92 is ON (connected) or OFF (disconnected) based on the dog clutch connection / disconnection signal DCL.
If it is FF (cut), the motor control is not executed. In addition, as described in the pump control, the abnormality of the regenerative device is detected,
When the error control described later is executed, the dog clutch 51 is disengaged. In this case, the motor control is not executed according to the determination in step S32. 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 selected position of the transmission 3 is in 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 the selected position of the transmission 3 is in the neutral position 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 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
/ 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. 14 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 by regenerative energy, and the motor is not operated. On the other hand, if it is larger than the discrimination value Xθ1 (L Aθ ≧ Xθ1), step S41
To start the motor control.

The accelerator opening detected value LAθ used in this step is the idle accelerator voltage value (zero point correction value) XAE set in the pump control described above.
Thus, since the motor control is always corrected to an appropriate value, the start determination of the motor control is appropriately performed. If the motor control is not to be executed, the ECU 60 sets the tilt angle control signal value ELM to the proportional solenoid valve 42 to zero (ELM = 0) in step S50 in FIG. 10 and outputs this. This allows
The piston 41a of the tilt angle cylinder 41 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 tilt angle cylinder 4
The switching valve 44 for controlling the supply and discharge of the pilot oil for driving the first piston 41a is turned off by cutting off the drive signal D1.
(Closed). In step S52, O
The shutoff valve 24, which is N (open), 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 output of the unload valve signal D3 is stopped and the unload valve (normally open) 25 disposed between the low-pressure oil pipeline P2 and the high-pressure oil pipeline P1 is turned off (open). And the low pressure oil pipeline P2. Step S54
In step S55, a rack limit signal R, which will be described later, which has been transmitted to the engine 1 when the motor is operating is turned off, and in step S55, the rack limit valid signal RE, which is also transmitted, is turned off. Finally, step S56
The value 0 (f2
= 0), thereby storing that the motor control is not performed.

On the other hand, when the motor control is started by executing step S41, the ECU 60
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. 15 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. At this time, as described in the previous pump motor control, the accelerator opening LAθ is always set to be zero when the foot is released from the accelerator pedal, so that the accelerator opening LAθ is corrected in accordance with the thus corrected accelerator opening LAθ. The set ELM reference value is always kept at an appropriate value. 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 this is calculated as E
The optimum tilt angle control signal EL is multiplied by the LM reference value.
The M 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 motor of the pump / motor 40 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. It is to change the output torque value due to the operation. Also, the vehicle speed V
(Or the engine rotational 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 when the oil temperature is lower than 70 ° C., for example, but the tilt angle control signal value ELM when 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 proceeds to 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, and its driving force is
0e, and transmitted to the drive wheels WR via the gear box 50 and the drive shafts 12, 10, and cover a part of the driving force at the time of starting and acceleration.

In step S46, the ECU 60 supplies a rack limiting 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.

[0055]

As described above, according to the braking energy regenerating device of the present invention, the accelerator operation amount detecting means for detecting the operation amount of the accelerator pedal, and the detection detected from the accelerator operation amount detecting means at the time of vehicle braking. The zero point correction value of the operation amount of the accelerator pedal is stored based on the value, and at the time of starting / acceleration of the vehicle, based on the stored zero point correction value,
Control means for correcting the operation amount detection value of the accelerator pedal and controlling the motor output torque of the pump / motor in accordance with the corrected operation amount of the accelerator pedal, so that the driver does not step on the accelerator pedal At this time (during idling), the execution of the motor control can be reliably prevented, and when the motor is operated, appropriate control according to the driver's intention can be performed, and generation of unintended driving force can be prevented.

[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 an accelerator voltage check routine of the braking energy regeneration device according to the present invention.

FIG. 12 is a graph showing an example of a relationship between an idle accelerator voltage of the braking energy regenerating device, an accelerator voltage shifted according to the idle accelerator voltage, and an accelerator opening according to the present invention.

FIG. 13 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 accordingly.

FIG. 14 is a graph showing an example of a relationship between a vehicle speed V and a discrimination value Xθ1 (accelerator start opening) during motor control of the braking energy regeneration device.

FIG. 15 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 these during a motor control of the braking energy regeneration device.

[Explanation of symbols]

 DESCRIPTION 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 Tilting cylinder 42 Proportional solenoid valve 43 Pilot hydraulic power source 50 Gear box 51 Dog clutch 52 Air tank 60 Control unit ( ECU) 61 Accelerator opening sensor (accelerator operation amount detecting means)

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

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. Accelerator operation amount detection means for detecting an operation amount of an accelerator pedal, and a zero point correction value of the operation amount of the accelerator pedal based on a detection value detected from the accelerator operation amount detection means during vehicle braking, and At start / acceleration, the accelerator pedal operation amount detection value is corrected based on the stored zero point correction value. And a control means for controlling a motor output torque of the pump / motor in accordance with the corrected operation amount of the accelerator pedal.