JP3079860B2 - 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] In consideration of ease of mounting on a vehicle such as a route bus, an engine is disposed behind the rear wheel drive shaft, and an energy regenerating device is disposed forward. The former is provided with a clutch and a transmission (transmission). The drive shaft differential device (through shaft type) has a configuration in which the latter is connected to the above-described differential device via a reduction gear device and a clutch, respectively.
L. 1992-NO. 482-90.

In such a braking energy regenerating device system, the output transmitted to the drive wheels is an output value obtained by multiplying the engine side torque by the gear ratio of the transmission,
It can be expressed as the sum of the output value obtained by multiplying the torque of the pump / motor by the gear ratio of the reduction gear device. Regardless of the magnitude of the torque generated by the braking energy regenerating device at the time of start / acceleration, the engine-side output and the pump / The sum of the motor side outputs must be equal to the output required by the driver.

[0005] Therefore, an engine torque (output) is obtained along an operation line that provides the best fuel efficiency characteristics from the engine's fuel efficiency / torque characteristics, and an output that is insufficient with respect to the output required by the driver is regenerated as braking energy. If the pump / motor of the braking energy regenerating device is operated and controlled in a predetermined pattern according to the accelerator opening and the engine speed (the vehicle speed may be used instead of the engine speed), it is possible to obtain fuel efficiency characteristics. This is a preferable control method.

[0006] The operation pattern of the pump / motor described above is as follows.
It is preferable that the braking energy is set most effectively and frequently used at the time of normal starting acceleration, for example, at the time of starting at the second speed, so that the engine-side output and the pump / motor-side output for obtaining the best fuel consumption characteristics are obtained. Is set to be less than the maximum output value obtained by multiplying the engine maximum torque by the second gear ratio of the transmission.

[0007] When the accumulator of the braking energy regenerating device does not store the braking energy necessary for the start, the torque on the engine side is adjusted and the required output is adjusted. To be able to obtain.

[0008]

At the time of start / acceleration at the third or higher speed, the pump / recovery of the braking energy regenerating device is performed in accordance with a predetermined operation pattern set based on the start / acceleration of the second speed. When the operation of the motor is controlled, the sum of the engine-side output and the pump / motor-side output becomes larger than the output required by the driver, and in some cases, becomes larger than the maximum output obtained only from the engine as the speed increases. Inconvenience occurs.

In this case, the engine-side torque can be adjusted. However, if the engine-side torque is adjusted, the fuel efficiency deviates from the operating line at which the best fuel efficiency characteristic is obtained, and the fuel is regenerated by the braking energy regenerating device. This method is not an advantageous method and cannot be adopted from the comparison between the energy and the deterioration of fuel consumption. Therefore, the present invention avoids the inconvenience that the sum of the engine-side output and the braking energy regenerator-side output exceeds the maximum output obtained only from the engine, regardless of the gear position of the transmission, and is advantageous in fuel consumption characteristics. It is an object to provide a braking energy regenerating device.

[0010]

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 connected to a drive system member for transmitting a driving force of an engine via a clutch /
The brake energy is operated by pumping the motor at the time of braking and converting the braking energy into hydraulic energy and storing it in the accumulator, while operating the motor at the time of start / acceleration and using the hydraulic energy stored in the accumulator as the start / acceleration energy. Control means for controlling a motor output torque of the hydraulic pump / motor in the regenerative device;
Connected to the engine and changing the output of the engine
A transmission for transmitting to the drive system member; and a shift speed detecting means for detecting a shift speed of the transmission, wherein the control means detects a shift speed by the shift speed detecting means.
The motor output torque of the hydraulic pump / motor and the engine
The sum of the output torque of the gin and the engine
So as not to exceed the maximum torque by only the shift stage is at the high speed stage
If you limit the maximum value of the motor output torque to a certain degree ,
In both cases, the output torque of the engine at each of the gears is
The model is designed to obtain the best fuel economy characteristics of the engine.
It is characterized by controlling the motor output torque .

[0011]

The output determined by the sum of the motor output torque of the pump / motor and the engine output torque at each shift speed of the transmission does not exceed the output determined from the maximum drive torque of only the normal engine at the shift speed. As described above, the maximum value of the motor output torque is limited to a smaller value at a higher speed, and the output torque of the engine at each speed is substantially maintained at a value at which the best fuel consumption characteristics of the engine can be obtained.

[0012]

An embodiment of the present invention will be described with reference to the drawings. The energy regenerating apparatus shown in FIGS. 1, 2 and 3 has a transmission 3 having a plurality of selectable gears,
Engine 1 for driving drive wheels via clutch 2
Piston type accumulator 2
0, a low-pressure hydraulic oil tank 30, a swash plate type variable displacement piston type pump / motor 40, a gear box 50, 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 via 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.

The high-pressure oil pipeline P1 has an accumulator 20
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.

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 inside 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.
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 operates,
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 are operated.
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 above-described dog clutch 51 is operated to be connected and disconnected by air pressure. The dog clutch 51 is connected to an air tank 52 via an electromagnetic three-port switching valve 53 for connecting a clutch and an electromagnetic three-port switching valve 54 for disengaging 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 drive 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 the ECU 60 sends a brake pressure detection signal PBK to the ECU 60.
Is supplied. The ECU 60 compares the magnitude of the discharge pressure PHY of the pump / motor 40 and the magnitude of the brake pressure PBK detected by the above-described discharge pressure sensor 89 with respective predetermined values, thereby accumulating the brake pressure by the pump operation of the pump / motor 40. And the operation switching control between the normal service brake and the normal service brake.

The engine 1 is provided with a fuel injection device 5, and 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 to limit the fuel injection amount in accordance with the accumulated pressure in the accumulator 20, as will be described in detail later. The governor control unit 67 detects the engine speed NE, and outputs the engine speed signal NE to the ECU 60.
To supply.

The transmission 3 has a vehicle speed sensor 8
3. T / M reverse sensor 84, T / M neutral sensor 85, and select position sensor 8 for detecting a gear position
6 for supplying a vehicle speed signal V, a T / M reverse signal TMR, a T / M neutral signal TMN, and a select position signal LTM to the ECU 60, respectively. FIG. 3 shows a configuration of the ECU 60 that controls the operation of the energy regenerating device. The ECU 60 includes a processor, a memory, an input / output circuit, and the like. The input side of the ECU 60 is connected to a main switch 6 for supplying a power on / off state signal.
4. an accelerator opening sensor 61 that detects an amount of depression of the accelerator pedal in conjunction with an accelerator pedal (not shown);
Two clutch sensors (CL1) 6 which detect the connection / disconnection of the engine clutch in conjunction with a clutch pedal (not shown) 6
2, (CL2) 63 and various sensors including the above-described brake pressure sensor are connected. Here, the engine clutch connection / disconnection sensor (CL1) 62 supplies a signal at a return limit (clutch connection) of a clutch pedal (not shown) to generate an O signal.
N, and the engine clutch connection / disconnection sensor (CL2) 63 is set so as to be turned ON by supplying a signal when the clutch pedal (not shown) is depressed (clutch disengagement). The half-clutch state can be detected by a combination of the sensor (CL1) 62 and the sensor (CL2) 63.

On the other hand, the above-mentioned various electromagnetic switching valves and various indicators are connected to the output side of the ECU 60. 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 with the accumulator signal PAC from the controller, 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 errors due to various error signals. Diagnostic lamp 6 that displays
There are nine.

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. It should be noted 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).
At a predetermined vehicle speed (for example, 60 km / h) or higher, the drive signal D9 is supplied to the disconnection switching valve 54 to prevent the pump / motor 40 from exceeding the allowable capacity, and the pump / motor 40 is turned off (disconnected).
Becomes When the dog clutch 51 is connected, the pump / motor 40 is driven by the drive shafts 10 and 12 and the gear box 50.
Through the driving wheels WR.

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.

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. 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, 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 above pump control, the tilt angle of the pump / motor 40 is set according to the driver's depression amount of the brake pedal, and the pump / motor 40 performs work corresponding to the depression amount of the brake pedal and performs braking. Energy will be recovered.

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. 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 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 the position, the motor control is not executed. On the other hand, if the determination result is NO, that is, if the vehicle is in the forward gear position, step S
Proceed to 34.

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 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 discrimination 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 by regenerative energy, and the motor is not operated. If the motor control is executed at the time of the load in which the accelerator opening LAθ is equal to or smaller than the discrimination value Xθ1, it is necessary to greatly reduce the engine output. But,
If the engine output is excessively reduced, the fuel consumption characteristics of the engine deteriorate, which is not preferable. On the other hand, if it is larger than the discrimination value Xθ1 (LAθ ≧ Xθ1), the process proceeds to step S4
The routine proceeds to 1 to start the motor control.

If 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.

On the other hand, when the motor control is started by executing step S41, the ECU 60
The tilt angle control signal value ELM of the swash plate 40d of 0 is set by executing a subroutine shown in FIG. EL
As a method of setting the M value, first, in step S70, an ELM 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 an ELM reference value corresponding to the vehicle speed V and the accelerator opening LAθ from the map.

Here, the relationship between the operation control of the pump / motor 40 and the operation control of the engine 1 during motor control will be described. When the accumulated pressure in the accumulator 20 is sufficient (for example, when the pressure in the accumulator 20 is 350 kg).
f / cm ² or more), the engine 1 is controlled along an operation line at which the engine 1 obtains the best fuel efficiency characteristics. FIG.
Reference numeral 5 indicates an equal fuel consumption curve of the engine 1, and indicates that the best fuel consumption characteristics can be obtained by controlling the operation of the engine 1 along the operation line shown by the broken line in the figure. Therefore, as described in steps S46 and S47 described later, a rack limit signal is supplied to the engine 1 to reduce the fuel injection amount to a shaft torque at which substantially the best fuel efficiency is obtained. On the other hand, the pump / motor 40
Is controlled to generate an output sufficient to compensate for the reduced engine-side output.

The ELM map shown in FIG. 14 is set on the basis of the second speed, since normal starting / acceleration is often performed at the second speed of the transmission 3. When the detected accelerator opening L Aθ is a value in a region surrounded by a solid line and a constant accelerator opening 100% line in FIG. 14, the XM2 value (for example, 700 mA) which is the maximum value as the ELM reference value ) Is set. In the region where the maximum value XM2 is set as the ELM reference value, the sum of the engine 1 output and the pump / motor 40 output is equal to the second output.
The output is substantially equal to the output obtained at the time of the maximum torque of the engine 1 when only the engine 1 is operated at the speed stage and the pump / motor 40 is not operated.

On the other hand, in a region where the detected accelerator opening L Aθ is smaller than the accelerator opening indicated by a broken line in FIG. 14, the ELM reference value is set to zero. In the region where the accelerator opening is small, the pump / motor 40 is not operated as a motor. If the ELM reference value is set to be smaller than the minimum value XM0 set corresponding to the broken line, the output required by the driver (the output corresponding to the detected accelerator opening LAθ) will not be obtained, causing inconvenience. The accelerator opening value indicated by the broken line in FIG. 14 corresponds to the accelerator opening determination value Xθ1 set in FIG.

When the detected accelerator opening L Aθ is the accelerator opening indicated by a dashed line in FIG. 14, the ELM reference value is set to the value XM1 and the detected accelerator opening L Aθ is set.
Is an intermediate value between the accelerator opening values corresponding to the XM2 value and the XM1 value in FIG. 14, or an intermediate value between the accelerator opening values corresponding to the XM1 value and the minimum value XM0, respectively. , The ELM value is calculated by a known interpolation method.

As described above, the output required by the driver is obtained from the pump / motor 40 by setting the ELM reference value in accordance with the accelerator opening L Aθ, and the same accelerator opening L Aθ is used. Even when the vehicle speed V is high, the ELM reference value set when the vehicle speed V is low is set larger than the ELM reference value set when the vehicle speed V is high.
Effective use of regenerative energy during low-speed acceleration, such as when starting, prevents the generation of black smoke.

In FIG. 14, since the ELM map is set based on the second speed, the vehicle speed V corresponds to the engine speed NE, and the vehicle speed V is used on the horizontal axis. Therefore, even when the ELM reference value is set based on the engine speed NE and the accelerator opening LAθ instead of the vehicle speed V, the setting map is a map similar to FIG. Next, in step S71, a correction coefficient K2 according to the oil temperature TOIL of the hydraulic oil tank 30 detected by the oil temperature sensor 91 is obtained, and this is multiplied by the ELM reference value to obtain the optimum tilt angle control signal ELM. The value (= ELM reference value × K2) is calculated. FIG. 16 shows the relationship between the oil temperature TOIL and the correction coefficient K2. The correction by the oil temperature TOIL of the hydraulic oil tank 30 does not require the correction of the ELM value when the oil temperature TOIL is lower than XTOIL (for example, 70 ° C.). If the oil temperature TOIL is 70 ° C or higher,
Correction is made to decrease the tilt angle control signal value ELM.
At high temperatures, the viscosity of the hydraulic oil decreases and the pump / motor 4
Since there is a risk of burning of 0, this is prevented by reducing the motor capacity.

In step S72, the ECU 60 determines the tilt angle control signal value EL for each speed stage of the transmission 3.
The maximum value (ELMax) of M is obtained, and the pump / motor 4
Limit output torque due to motor operation of 0. When the braking energy is regenerated through the reduction gear (gear box) 50 different from the transmission 3, as described above, the sum of the output by the motor operation of the pump / motor 40 and the output on the engine 1 side is a normal value. It is required that the output value does not exceed the output value corresponding to the maximum driving torque (normally, the maximum driving torque) by only the engine 1. Since the ELM reference value set based on FIG. 14 is set with reference to the second speed, at the shift speed higher than the second speed, the motor / pump motor 40 operates. The output torque is provided with a limit value for each shift speed so that the drive torque does not exceed the allowable maximum torque value.

More specifically, the maximum value ELMmax is
The XELM1 value (for example, 700 mA) at the first and second speeds, the XELM2 value (for example, 500 mA) at the third speed, and the XELM3 value at the fourth and fifth speeds are obtained from the table shown in Table 1. (For example, 400 mA). As described above, the maximum value ELMmax is set to a value at which the output torque of the pump / motor 40 is limited as the speed increases. The established gear position of the transmission 3 may be detected by the select position sensor 86 as in the embodiment, or may be estimated from a gear ratio calculated from the engine speed NE and the vehicle speed V. It may be.

[0059]

[Table 1] In step S73, the ECU 60 executes step S70,
In S71, the tilt angle control signal value ELM calculated according to the accelerator opening L Aθ, the vehicle speed V (or the engine speed NE) and the oil temperature TOIL is compared with the maximum value ELMmax set in Step S72. Therefore, when the comparison result is ELM ≧ ELMmax, in step S75,
The tilt angle control signal value ELM is reset to the maximum value ELMmax. When the comparison result is ELM <ELMmax, E
No LM value restriction is performed.

As described above, by limiting the ELM value to the maximum value ELMmax set for each gear, the output of the engine 1 is maintained at a value at which the best fuel economy characteristics can be obtained. The torque transmitted to the system can be kept below the maximum torque allowed for it. Returning to the motor control flow, the ECU 60 returns to FIG.
In step S42, a control signal corresponding to the ELM value set as described above is output to the proportional solenoid valve 42. In step S43, a drive signal D1 is output, and the switching valve 44 is turned ON (open). The pilot hydraulic pressure is supplied to the tilt angle cylinder 41 via the proportional solenoid valve 42. Thus, the swash plate 40d of the pump / motor 40 is set to a tilt angle corresponding to the ELM value. Next, in step S44, a shutoff valve signal D2 is output to the shutoff valve 26,
N (open), and in step S45, an unload valve signal D3 is supplied to the unload valve (normally open) 25 to turn it on (closed), and the pressure of the high-pressure oil line P1 is reduced to the low-pressure oil line P2. To avoid escaping. As a result, the pump / motor 40 is driven by the high-pressure hydraulic oil stored in the accumulator, and the driving force is supplied to the drive shaft 40e, the gear box 50, and the drive shaft 1.
The driving force is transmitted to the driving wheels WR via the wheels 2 and 10 and covers a part of the driving force at the time of starting or accelerating.

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. As described above, the rack limit signal R limits the output torque of the engine 1 during motor control. The output limit of the engine 1 is based on the engine speed NE and the accumulated pressure PAC of the accumulator 20. Is determined.

FIG. 17 shows the relationship between the engine speed NE and the rack limit value R. If a sufficient accumulated pressure (350 kgf / cm ² or more) is secured in the accumulator 20, the rack limit value R Is set to a value given by the solid line in FIG. 17, and the thus set rack limit signal R is supplied to the fuel injection device 5 to regulate the maximum fuel injection amount to a value corresponding to the rack limit value R. Thus, the engine 1 is adjusted to the shaft torque at which the best fuel economy characteristics are obtained.

[0063] On the other hand, when the accumulated pressure of the accumulator 20 is 350 kgf / cm ² or less as described above is sufficient accumulator volume (350 kgf / cm ² or more) during motor operation of the pump / motor 40 when being secured And the sum of the output of the engine 1 and the output of the pump / motor 40 becomes insufficient with respect to the output required by the driver. The insufficient output is compensated by relaxing the rack limitation of the engine 1. In this case, the rack limit value R is set to a value indicated by a solid line when the accumulated pressure is 350 kgf / cm ² or more, and to a value indicated by a broken line when the accumulated pressure is 200 kgf / cm ² or less. , when the pressure accumulation amount is a value between 350 kgf / cm ² and 200 kgf / cm ² is set by interpolation.

In step S 47, a rack limit valid signal RE is output to the governor control unit 67 in order to ensure that the output of the engine 1 supplied to the fuel injection device 5 is limited. Prevents operation. In addition, the present invention is not limited to the embodiment in which the engine 1 and the energy regenerating device are respectively arranged with the through shaft type differential device interposed therebetween, and the energy regenerating device is connected to the PTO output shaft of the transmission 3. It can also be applied to things.

[0065]

As described above, according to the braking energy regenerating apparatus of the present invention, the control means for controlling the motor output torque of the hydraulic pump / motor is connected to the engine, and the engine is connected to the engine.
A transmission for shifting the output of the gin and transmitting the output to a drive system member;
A gear position detecting means for detecting a gear position of the transmission, wherein the control means detects the gear position by the gear position detecting means
And motor output torque of hydraulic pump / motor and engine
Output torque depends only on the engine at each gear
In order not to exceed the maximum torque, the maximum value of the motor output torque is limited to a smaller value as the shift speed is higher , and
The output torque of the engine at each shift speed is
Control the motor output torque to a value that gives good characteristics
Since the way, in all gear, the sum of the motor output torque and the engine output torque, while reducing not exceed the maximum torque by only normal engine,
Without causing deterioration of fuel consumption characteristics of the engine, can be utilized recovered by energy just enough efficiently.

[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 ELM reference value setting subroutine during motor control 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 reference value set in accordance with 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.

FIG. 15 is an iso-fuel efficiency diagram showing the relationship between the shaft torque according to the engine speed and the fuel efficiency characteristics of the engine according to the present invention.

FIG. 16 is a graph showing an example of a relationship of a correction coefficient K2 according to a hydraulic oil temperature TOIL at the time of pump / motor control of the braking energy regeneration device.

FIG. 17 is a graph showing an example of the relationship between the engine speed NE and the accumulated pressure amount and the fuel supply limit value (rack limit value) according to these during the motor control of the braking energy regeneration device according to the present invention.

[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 displacement piston pump / motor 41 Tilting cylinder 42 Proportional solenoid valve 43 Pilot oil pressure source 50 Gear box 51 Dog clutch 60 Control unit (ECU) 67 governor control unit 83 vehicle speed sensor 86 select position sensor (gear position detecting means) 88 pressure accumulation sensor

──────────────────────────────────────────────────続 き Continued on the front page (58) Field surveyed (Int.Cl. ⁷ , DB name) B60T 1/10 B60K 25/00 B60L 11/00

Claims (1)

(57) [Claims] 1. A hydraulic pump interposed in an oil passage between a low-pressure tank for storing hydraulic oil and an accumulator for accumulating hydraulic energy and connected via a clutch to a drive system member for transmitting a driving force of an engine. A brake that operates a pump during braking to convert braking energy into hydraulic energy and stores it in the accumulator, while operating the motor during start / acceleration and uses hydraulic energy stored in the accumulator as starting / acceleration energy. In the energy regenerating apparatus, a control means for controlling a motor output torque of the hydraulic pump / motor is connected to the engine, and the output of the engine is shifted.
A transmission for transmitting the drive system member, and a gear position detecting means for detecting a gear position of the transmission, said control means, gear position detection by the gear position detecting means
Output, the motor output torque of the hydraulic pump / motor
The sum of the torque and the output torque of the engine
Gear shifting so that the maximum torque from the engine alone is not exceeded
With stage is limited to a small maximum value of the motor output torque as is the high speed stage, the said engine at each gear
Output torque is a value that can obtain the best fuel efficiency characteristics of the engine
A braking energy regenerating device characterized by controlling a motor output torque so that