JPH068901Y2 - Brake energy regeneration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION (Industrial field of application) The present invention relates to a brake energy regeneration device that regenerates braking energy collected when a vehicle is decelerated as running energy.

(Prior Art) Conventionally, as a brake energy regeneration device of this type, there is one disclosed in, for example, JP-A-62-31522.

In this type, a pump motor is connected to a wheel drive system via an electromagnetic clutch, one port of the pump motor is connected to an accumulator via a high pressure oil passage, and the other port is connected to an oil via a low pressure oil passage. It is connected to the tank. When the vehicle decelerates, the wheel drive system is connected to the pump motor to operate as a pump to brake the wheel drive system using the pump motor as a load, and the high pressure oil is accumulated in the accumulator to recover the brake energy. It has become. When the vehicle starts or accelerates, the pump motor is connected to the wheel drive system, and the pump motor is supplied with high-pressure oil that has accumulated pressure in the accumulator to operate the pump motor as a motor. It is designed to be reproduced as drive energy for the system.

Here, the braking torque and the driving torque in the regenerative device are controlled by controlling the swash plate angle (swash plate tilt angle) of the pump motor to control the flow rate of the pump motor.

(Problems to be solved by the invention) However, in such a conventional device, the recovered energy is regenerated as drive energy when the vehicle is started or accelerated, and the swash plate angle of the pump motor is set only to the accelerator opening degree. Since it was controlled by controlling it, there were the following problems.

That is, in order to obtain the torque required for starting and accelerating, it is necessary to provide a gear for increasing the speed between the wheel drive system and the pump motor, which complicates the structure. Further, if the swash plate angle of the pump motor is controlled so as to correspond only to the accelerator opening, even if the accelerator opening is constant, the torque obtained when the driving energy is large and when the driving energy is small is different, and therefore, it is preferable. Torque control and torque control with the engine are difficult and give the driver a feeling of discomfort.

The present invention aims to solve such a problem.

(Means for Solving the Problems) This invention is directed to a swash plate type pump motor 52 connected to a wheel drive system via an electromagnetic clutch 51 as shown in FIG.
In the brake energy regeneration device that regenerates the braking energy recovered during deceleration as running energy by the high-pressure side accumulator 53 and the low-pressure side accumulator 54 connected to the pump motor 52, a means 55 for detecting the vehicle speed, and an engine speed. Means 56 for detecting
Means 58 for detecting the position of the control lever of the fuel injection pump, and the high pressure side and low pressure side accumulator 5
Means 59, 60 for detecting the pressures 3, 54, and means 61 for calculating the required torque of the engine and the drivable torque of the pump motor 52 on the basis of these detected values and comparing both torques are provided. According to the comparison, when the drivable torque is larger than the required torque during steady running, the driving force of the pump motor 52 causes the pump motor 52 to travel according to the required torque and the pressure difference between the accumulators 53 and 54. First control means 63 for controlling the swash plate angle and disengaging the engine clutch 62 to cut fuel injection.
When the drivable torque is smaller than the required torque during steady running, the engine clutch 62 is connected so that the output of the engine is also used, and the fuel injection amount is controlled according to the difference between the required torque and the drivable torque. Two control means 64
And.

(Operation) Therefore, according to the comparison between the required torque of the engine and the drivable torque of the pump motor, the vehicle travels with the driving force of the pump motor and the engine together during the steady traveling, and travels with the driving force of the pump motor. Sometimes
The swash plate angle of the pump motor is controlled according to the required torque and the pressure difference between the accumulators, and the fuel injection amount is controlled according to the difference between the required torque and the drivable torque when the engine is used together. A gearbox is not required between the pump motor and the pump motor, while torque control is always achieved as required.

(Embodiment) FIG. 2 is a configuration diagram showing an embodiment of the present invention, in which an output shaft of an engine body 1 is connected to wheels 6 via an engine clutch 2, a transmission 3, a propeller shaft 4 and a final reduction gear 5. ing. A pump motor 8 is connected to the final reduction gear 5 via an electromagnetic clutch. A low-pressure side accumulator 11 is connected to one port of the pump motor 8 via a low-pressure oil passage 10 in which a first solenoid valve 9 is interposed, and a second solenoid valve 12 is interposed in the other port. The high pressure side accumulator 14 is connected via the high pressure oil passage 13. Further, the high pressure oil passage 13 and the low pressure oil passage 10 are
The solenoid valve 15 is configured to be connectable by bypassing the pump motor 8.

The control unit 16 including a microcomputer or the like includes an accelerator signal from an accelerator switch 18 for detecting depression of an accelerator pedal 17, a vehicle speed signal from a vehicle speed sensor 19, a vehicle acceleration signal from an acceleration sensor 20, and a transmission 3 of the transmission 3. A shift position signal from a shift position sensor 21 that detects a gear position, pressure signals from pressure sensors 22 and 23 that detect the pressures of the high pressure side accumulator 14 and the low pressure side accumulator 11, and a control lever position of a fuel injection pump 24 are detected. A lever position signal from the lever position sensor 25, a brake signal from a pressure sensor that detects an operating state of a brake valve of a service brake (not shown), a brake signal from an exhaust brake operation switch, and the like are input.

Based on the detection signals, the control unit 16 connects the electromagnetic clutch 7 at the time of predetermined deceleration, opens the first and second electromagnetic valves 9 and 12 of the low pressure oil passage 10 and the high pressure oil passage 13, and opens the bypass passage 26. The third solenoid valve 15 is closed, the pump motor 8 is operated as a pump, and the oil in the low pressure side accumulator 11 is pumped to the high pressure side accumulator 14.
The brake energy is recovered by accumulating the pressure.

Then, the control unit 16 controls the collected braking energy to be reproduced as traveling energy during a predetermined steady traveling, based on the signals.

Next, the operation of energy regeneration control in the control unit 16 will be described with reference to FIGS.

First, in S101, it is determined from the accelerator signal of the accelerator switch 18 whether or not the accelerator pedal 17 is depressed (presence or absence of an accelerator request). The judgment in S101 is YE
If S, proceed to S102 and thereafter.

In S102 and S103, it is determined from the vehicle speed signal of the vehicle speed sensor 19 whether the vehicle speed V is a predetermined value Vmax (for example, 10 km / h) or more.

In S104 and S105, the pump motor 8 for obtaining the vehicle speed V
The rotation speed Np of is calculated from the following formula.

Np = (V / 2πr) · iDF · (1000/60) where r is the tire radius and iDF is the gear ratio of the final reduction gear device 5. Next, the calculated rotation speed Np is the pump motor 8
It is determined whether or not the allowable rotation speed Npmax is less than or equal to.

In S106～S109, from the pressure signal of the pressure sensors 22 and 23, whether the pressure _{P H} of the high-pressure accumulator 14 is higher than a predetermined value, whether the pressure _{P L} in the low-pressure accumulator 11 is below a predetermined value, both the accumulator 14 , 11 is greater than or equal to a predetermined value (for example, 10 kg / cm ² ) or not.

Each determination of S103, S105, S107 to S109 is O
If it is K, the process proceeds to S110 and below, and if it is not OK, the process proceeds to S133 and below, which will be described later, for normal running.

In S110 to S112, the control lever position R of the fuel injection pump 24 is detected from the lever position signal of the lever position sensor 25, the engine speed Ne is detected from the signal of the vehicle speed sensor 19, and the acceleration α is detected from the signal of the acceleration sensor 20. Detect. The engine speed Ne is calculated by the following formula or by multiplying the speed Np of the pump motor 8 by the gear ratio iTM of the transmission 3. The acceleration α may be calculated from the rate of increase in vehicle speed.

Ne = (V / 2πr) · iDE · iTM (1000/6
0) Next, in S113, the absolute value of the acceleration α is the reference value αmax.
(For example, 0.01 G), it is determined whether or not
If α | ≦ αmax, that is, if the vehicle is in a steady running state, S
114, and proceed to S115. If | α | ≦ αmax, the routine proceeds to S133 and normal traveling is performed.

In S114, the required torque Te of the engine is retrieved from the map of FIG. 4 stored in advance in the control unit 16 according to the engine speed Ne and the control lever position R. In S115, the required torque Te of the engine is compared with the drivable torque Tmax of the pump motor 8.
The drivable torque Tmax is retrieved from the map of FIG. 5 stored in the control unit 16 based on the maximum differential pressure ΔPmax that can be set by this system and the maximum flow rate Qthmax with respect to the rotation of the pump motor 8.

If the determination in S115 is Te ≦ Tmax, the routine proceeds to S116, where the differential pressure ΔPo that obtains the required torque Te at Qthmax is retrieved from the map of FIG. 6 stored in the control unit 16, and then in S117, the pump motor The required flow rate Qth of the pump motor 8 is calculated from the maximum flow rate Qthmax of No. 8 and the differential pressures ΔPo and ΔP.

Then, in S118, the requested flow rate Qth is the maximum flow rate Qt.
It is determined whether it is smaller than hmax, and Qth <Qth
If it is max, the process proceeds to S119 and below so that the vehicle travels only by the driving force of the pump motor 8. Also, Qth ≧
If Qthmax, or if the determination in S115 is Te
If> Tmax, the process proceeds to S124 and below so that the vehicle is driven by the driving force of the pump motor 8 and the output of the engine.

In S119 to S121, the engine clutch 2 is disengaged,
The fuel supply from the fuel injection pump 24 is cut off, and the electromagnetic clutch 7 of the pump motor 8 is connected. In S122,
From the flow rate-control current characteristic of the pump motor 8 shown in FIG. 7, a swash plate drive current A corresponding to the required flow rate Qth of the pump motor 8 is obtained and output to the swash plate drive device 27 as a control output. In S123, the first and second solenoid valves 9 and 12 of the low pressure oil passage 10 and the high pressure oil passage 13 are opened, and the third solenoid valve 15 of the bypass passage 26 is closed.

As a result, during steady traveling in which the driving force of the pump motor 8 is large, the pump motor 8 is connected to the wheel drive system, high pressure oil is supplied to the pump motor 8 from the high pressure side accumulator 14, and the vehicle is driven by the driving force of the pump motor 8. At the same time, the swash plate angle of the pump motor 8 is controlled to secure a driving force that matches the required torque Te of the engine.

Further, in S115 and S118, Te> Tmax, Qth
When it is determined that ≧ Qthmax, the required flow rate Qth of the pump motor 8 is set to the maximum flow rate Qthmax in S124, and the drive torque Tp of the pump motor 8 is calculated from the differential pressure ΔP of the accumulators 14 and 11 in S125. (See FIG. 6) In S126, the insufficient torque Ta is obtained from the difference between the required torque Te and the driving torque Tp. And
In S127 to S130, the control lever position R of the fuel injection pump 24 is searched from the map of FIG. 8 stored in the control unit 16 based on the insufficient torque Ta and the engine speed Ne, and the engine clutch 2 and the electromagnetic clutch 7 are connected. Then, the control output Er corresponding to the control lever position R is obtained from the output characteristic shown in FIG. 9 and output to the governor of the fuel injection pump 24. In S131, the swash plate drive current A (see FIG. 7) corresponding to the required flow rate Qthmax of the pump motor 8 is output to the swash plate drive device 27,
In S132, the first and second solenoid valves 9 and 12 of the low pressure oil passage 10 and the high pressure oil passage 13 are opened, and the third solenoid valve 1 of the bypass passage 1 is opened.
Close 5

Thus, when the driving force of the pump motor 8 is insufficient with respect to the required torque Te of the engine during steady running, fuel is supplied from the fuel injection pump 24 according to the insufficient torque Ta, and the output of the engine is also used. To run.

On the other hand, S103, S105, S107 to S109, S1
If it is determined that the vehicle is traveling normally in S13, the normal fuel injection amount control according to the operating state of the fuel injection pump 24 is performed in S133, and the low pressure oil passage 10 and the high pressure oil passage 1 are executed in S134.
3, the first and second solenoid valves 9 and 12 are closed, and the bypass passage 2
6, the third solenoid valve 15 is opened, the electromagnetic clutch 7 is disengaged in S135 and S136, and the engine clutch 2 is engaged.

Therefore, according to the present embodiment, since the recovered braking energy is reproduced as traveling energy during steady traveling,
Since it is not necessary to provide a speed increaser or the like between the pump motor 8 and the wheel drive system, the structure can be simplified.

When the drivable torque of the pump motor 8 is larger than the required torque of the engine, the swash plate angle of the pump motor 8 is controlled according to the required torque and the pressure difference between the accumulators 14 and 11, and the driving force of the pump motor 8 is controlled. On the other hand, when the drivable torque of the pump motor 8 is smaller than the required torque of the engine on the other hand, the fuel injection amount from the fuel injection pump 24 is controlled according to the shortage, and the output of the engine is also used. , Energy can be effectively regenerated, and the required torque corresponding to the operating condition can be always secured, and a good driving feeling can be obtained.

Since the energy is sufficiently used in steady running, the amount of energy that can be recovered during the next braking can be made sufficiently large.

(Effect of the Invention) As described above, the present invention uses the swash plate type pump motor connected to the wheel drive system via the electromagnetic clutch, and the high-pressure side accumulator and the low-pressure side accumulator connected to the pump motor during deceleration. In a brake energy regeneration device for reproducing the collected brake energy as running energy, a means for detecting a vehicle speed, a means for detecting an engine speed, a means for detecting a control lever position of a fuel injection pump, the high pressure side and the low pressure side. A means for detecting the pressure of the accumulator on the side and a means for calculating the required torque of the engine and the drivable torque of the pump motor on the basis of these detected values and comparing both torques are provided. If the driveable torque is greater than the required torque during traveling, the drive force of the pump motor First control means for controlling the swash plate angle of the pump motor according to the required torque and the pressure difference between the two accumulators so as to travel more, and disengaging the engine clutch to cut off fuel injection; When the torque is smaller than the required torque, the engine clutch is connected so that the output of the engine is also used, and the second control means for controlling the fuel injection amount according to the difference between the required torque and the drivable torque is provided. A speed increaser is not required between the pump motor and the wheel drive system, the structure is simplified, and torque control is always ensured as required, and a good driving feeling is obtained.

[Brief description of drawings]

FIG. 1 is a block diagram of the present invention, FIG. 2 is a block diagram showing an embodiment of the present invention, FIGS. 3 (a) to 3 (d) are flow charts showing control contents, and FIGS. It is a graph which shows data. DESCRIPTION OF SYMBOLS 1 ... Engine body, 2 ... Engine clutch, 3 ... Transmission, 4 ... Propeller shaft, 5 ... Final reduction gear, 6 ... Wheels, 7 ... Electromagnetic clutch, 8 ... Pump motor,
9 ... 1st solenoid valve, 10 ... Low pressure oil passage, 11 ... Low pressure side accumulator, 12 ... 2nd solenoid valve, 13 ... High pressure oil passage, 14 ...
High-pressure side accumulator, 16 ... Control unit,
18 ... Accelerator switch, 19 ... Vehicle speed sensor, 20 ... Acceleration sensor, 21 ... Shift position sensor, 22, 23 ... Pressure sensor, 24 ... Fuel injection pump, 25 ... Lever position sensor, 27 ... Swash plate drive device

Claims (1)

[Scope of utility model registration request] 1. A brake energy recovered during deceleration is used as running energy by a swash plate type pump motor connected to a wheel drive system via an electromagnetic clutch, and a high pressure side accumulator and a low pressure side accumulator connected to the pump motor. In the regenerative braking energy regeneration device,
A means for detecting the vehicle speed, a means for detecting the engine speed, a means for detecting the position of the control lever of the fuel injection pump, a means for detecting the pressures of the high-pressure side and low-pressure side accumulators, and detection values thereof. Based on this comparison, a means for calculating the required torque of the engine and the drivable torque of the pump motor and comparing both torques is provided, and when the drivable torque is larger than the required torque during steady running in accordance with this comparison, the pump is First control means for controlling the swash plate angle of the pump motor in accordance with the required torque and the pressure difference between the two accumulators so as to travel by the driving force of the motor, and disengaging the engine clutch to cut off fuel injection;
Second control in which when the drivable torque is smaller than the required torque during steady running, an engine clutch is connected so that the output of the engine is also used, and the fuel injection amount is controlled according to the difference between the required torque and the drivable torque. And a braking energy regenerating device.