JPH068900Y2 - Brake energy regeneration device - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION <Industrial field of application> The present invention relates to a brake energy regenerator for recovering deceleration energy during vehicle deceleration, and more particularly to a flow rate control technique for a pump motor when the regenerator is operating.

<Prior Art> Conventionally, as a brake energy regenerating 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 pump motor is connected to the wheel drive system to operate as a pump to brake the wheel drive system using the pump motor as a load and to accumulate high pressure oil in the accumulator to recover deceleration energy. It is configured.

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

The stored deceleration energy is, for example, when the vehicle starts.
The pump motor is connected to the wheel drive system to act as a motor and used as drive energy for the wheel drive system.

<Problems to be Solved by the Invention> By the way, in such a conventional device, the tilt angle of the swash plate of the pump motor is controlled so as to correspond only to the depression amount of the brake pedal. In this case, when the accumulator pressure increases due to the pump action of the pump motor during deceleration, the braking torque increases even if the brake pedal depression amount is constant. If the control is performed in correspondence with only the amount of depression, there is a problem that the braking torque requested by the driver (depression amount of the brake petal) and the actual braking torque are different during deceleration and the driver feels uncomfortable. .

The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a brake energy regenerative device capable of obtaining a braking torque corresponding to a brake pedal depression amount even when the accumulator pressure changes during deceleration. .

<Means for Solving the Problems> Therefore, the present invention, as shown in FIG. 1, is generated by a brake operation detecting means, a hydraulic pressure detecting means for detecting each hydraulic pressure of the high pressure side and low pressure side accumulators, and a brake operation. Brake operation output detecting means for detecting the brake operation output, request torque braking calculating means for calculating the request braking torque based on the output value detected by the brake operation output detecting means, and operation of the request braking torque calculating means And a pump motor flow rate control means for controlling the flow rate of the pump motor to match the required braking torque based on the differential pressure between the high pressure side and the low pressure side calculated from the value and the detection value of the hydraulic pressure detection means. .

<Operation> In the above configuration, it is detected by the brake operating means that the driver has operated the brake. When this brake operation is performed, the brake operation output detection means detects the brake operation output generated corresponding to the driver's brake operation, and the required braking torque calculation means detects the brake operation output based on the detected brake operation output value. Calculates the braking torque requested by the driver. Further, the respective hydraulic pressures of the high pressure side accumulator and the low pressure side accumulator are detected by the hydraulic pressure detecting means. Then, based on the calculated value and the differential pressure of both accumulators calculated by the respective detected hydraulic pressures of the high-pressure side and low-pressure side accumulators, the pump motor flow rate control means obtains the pump motor flow rate that matches the required braking torque. Control pump motor flow rate. As a result, the braking torque required by the driver can be obtained regardless of changes in the accumulator hydraulic pressure.

<Embodiment> An embodiment of the present invention will be described below with reference to the drawings.

In FIG. 2 showing the configuration of this embodiment, an engine body 1
The output shaft of is connected to wheels 6 via an engine clutch 2, a transmission 3, a propeller shaft 4 and a final reduction gear device 5. The final speed reducer 5 has an electromagnetic crack 7
The pump motor 8 is connected via. 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 configured to be connectable by bypassing the pump motor 8 by the fifth solenoid valve 43.

On the other hand, when the brake pedal 15 is depressed, the brake valve 15 controls the air pressure from the air reservoir 17 in accordance with the depression angle or the like to generate an air pressure corresponding to the depression angle or the like through the air passage 18. It is supplied to the relay valve 20 of the booster 19 as an indication pressure. The relay valve 20 supplies the air having the same pressure as the indicated pressure from the air reservoir 17 to the air booster 19
To generate a hydraulic pressure to spread the brake shoe 22 with each wheel cylinder 21 to generate a braking force.

Further, the exhaust brake switch 23 is used for the engine clutch 2
The clutch switch 24 is turned on when the vehicle is in the connected state, the exhaust shutter 26 provided in the exhaust passage 25, and the air cylinder 27 for driving
And a control lever switch 31 of the fuel injection pump 30 which is turned on when the control lever is in the idle position and the solenoid valve 29 interposed in the air passage 28 which connects the air reservoir 17 and the air reservoir 17 constitute a series circuit. Therefore, when the engine brake 2 is in the connected state and the control lever is in the idle position, when the exhaust brake switch 23 is turned on, the solenoid valve 29 opens and compressed air from the air reservoir 17 passes through the air passage 28. The exhaust shutter 26 is supplied to the air cylinder 27 to drive the exhaust shutter 26 to generate a braking force by the exhaust brake.

A third solenoid valve 32, which will be described later, is provided in each of the air passages 18 and 28.
And the fourth solenoid valve 33 is interposed.

The control unit 35 including a microcomputer includes a vehicle speed signal from a vehicle speed sensor 36, a gear position signal from a shift position sensor 37 for detecting a gear position of the transmission, a high pressure oil passage 13, a low pressure oil passage 10, an air passage. Each pressure sensor 38 to detect each pressure of 18, 28
The pressure signal from 41 is input. Then, the braking torque required by the driver is calculated based on each of these input signals, and the flow rate of the pump motor 8 is set from this calculated value and the differential pressure in both oil passages 13 and 10, and is set to the flow rate value. The drive current of the swash plate drive device 42 is controlled so that the swash plate tilt angle is matched to each other, and the high-pressure oil passage 13, the low-pressure oil passage 10 and the air passages 18, 28 are respectively interposed by first to fifth electromagnetic waves. Valves 9, 12, 32, 33, 43
The open / close control is performed to control the selection of operating the normal brake device or the pump motor 8.

Here, the control unit 35 corresponds to the required torque calculation means and the pump motor flow rate control means, the pressure sensors 38 and 39 correspond to the hydraulic pressure detection means, the pressure sensors 40 and 41 correspond to the brake operation detection means, and the pressure sensors 40 and 41 The shift position sensor 37 corresponds to a brake operation output detecting means.

Next, the operation of the brake control in the control unit of this embodiment will be described with reference to the flowchart of FIG.

First, in step (indicated by S in the drawing, the same applies hereinafter) 1, it is determined based on a pressure signal from the pressure sensor 40 or 41 whether or not the driver has performed a brake operation (brake request is present). When the determination in step 1 is YES, the process proceeds to step 2.

In step 2, the vehicle speed V is detected based on the vehicle speed signal from the vehicle speed sensor 36.

In step 3, the detected vehicle speed V is a predetermined value (for example, 5 km
/ h) Judge whether or not more than. If it is less than the predetermined value, almost no deceleration energy is obtained even if the pump motor 8 is driven, so the routine proceeds to step 37, which will be described later, to perform a normal brake operation. When it is equal to or larger than the predetermined value, the process proceeds to step 4.

In step 4, the expected rotation speed N _P of the pump motor 8 which is the rotation speed when the pump motor 8 is connected at the current vehicle speed is calculated from the detected vehicle speed V and the gear ratio i _DF of the final reduction gear. To do.

In step 5, it is determined whether or not the calculated expected rotation speed N _P of the pump motor 8 is less than or equal to the maximum allowable rotation speed N _{PMAX of the} pump motor 8. When N _P ≧ N _PMAX, the routine proceeds to step 37 to protect the pump motor 8 and the normal braking operation is performed. If N _P <N _PMAX , go to step 6.

In step 6, the pressures P _H and P of the high pressure side accumulator 14 and the low pressure side accumulator 11 are based on the signals from the pressure sensors 38 and 39 provided in the high pressure oil passage 13 and the low pressure oil passage 10, respectively.
_L is detected, and the differential pressure Δ
Calculate P (= P _H −P _L ).

In step 7, P _H determines whether less than or equal to the maximum allowable pressure value P _HMAX of the high pressure accumulator 14 (for example 380Kg / cm ^2). When P _H > P _HMAX , the energy accumulation is considered to be the limit, and the routine proceeds to step 37 to perform a normal brake operation. P _H ≦
If P _HMAX , proceed to step 8.

In step 8, it is determined whether or not P _L is equal to or higher than the minimum allowable pressure value P _{LMIN of the} low pressure accumulator 11 (for example, 20 Kg / cm ² ). When P _L <P _LMIN , energy recovery will cause cavitation and the like on the low-pressure accumulator 11 side, so energy recovery is not performed and the routine proceeds to step 37 for normal braking operation. If P _L ≧ P _LMIN , go to step 9.

In step 9, it is determined whether or not ΔP is a differential pressure capable of energy recovery, for example, 10 Kg / cm ² or more. ΔP <
When the value is 10, the recovery operation is impossible, and therefore the process proceeds to step 37 and the normal braking operation is performed. When ΔP ≧ 10, it is determined that the recovery operation is possible, and the process proceeds to the next step 10.

In step 10, it is judged already discharge pressure of the brake valve 15, which is detected by the pressure sensor 40, i.e., the air pressure P _A of the air passage 18 or 0 or not for the determination of Step 1. P _A
When = 0, it is determined that the brake request from the driver in step 1 is not due to the foot brake, and the process proceeds to step 11. The required braking torque T ₁ based on the foot brake operation is set to 0, and steps 12 and 13 described below are not executed. On the other hand, when P _A > 0, the routine proceeds to step 12, where the required braking torque T ₁ based on the foot brake is stored in advance in the control unit 35, and P _A and T in FIG.
Search from ₁ map.

In step 13, it is determined whether the retrieved T ₁ is less than or equal to a predetermined value T ₀ . When T ₁ > T ₀ , it is determined that the braking is sudden, and the routine proceeds to step 37, where safety is achieved as a normal braking operation. When T ₁ ≦ T _0, the process proceeds to step 14.

In step 14, it is determined whether or not the air pressure P _B of the air passage 28 based on the exhaust brake operation already detected by the pressure sensor 41 for the determination of step 1 is 0. When P _B = 0, it is determined that the brake request from the driver in step 1 is not due to the exhaust brake, and the process proceeds to step 15, and the required braking torque T ₂ based on the exhaust brake operation is set to 0, and the following steps 16 and 17 are executed. do not do.

On the other hand, when P _B > 0, the routine proceeds to step 16, where the gear ratio i obtained from the shift position signal from the shift position sensor 37.
_The engine speed N _e is calculated from the following formula based on _TM , the vehicle speed V, and the gear ratio i _DF of the final reduction gear device 5.

Here, r is a tire radius.

In step 17, the required braking torque T ₂ based on the exhaust brake is retrieved from the map of _Ne and T ₂ of FIG. 5 stored in advance in the control unit 35.

In this manner, it is determined whether the driver's braking request is due to the foot brake, the exhaust brake, or both, and the braking torque corresponding to each is calculated.

Then, in step 18, the sum T of the required braking torques T ₁ and T ₂ obtained in steps 10 to 17, that is, the braking torque required for the pump motor 8 is calculated.

In step 19, the preset high-pressure side accumulator 14
The pump motor flow rate Q _tho at the differential pressure ΔP ₀ between the low pressure side accumulator 11 and the low pressure side accumulator 11 is searched from the calculated braking torque T by the map of FIG. 7.

Here, FIG. 7 shows that the relationship between the differential pressure ΔP and the flow rate Q of the pump motor 8 at a constant braking torque shown in FIG. The pressure difference ΔP ₀ between the accumulator 14 and the low pressure side accumulator 11 is set in advance, and the relationship between the flow rate Q _tho of the pump motor 8 and the braking torque T at ΔP _{0 which} is the basis of the above equation is shown.

At step 20, the pump motor flow rate Q _tho and Δ at ΔP ₀ obtained based on the braking torque T obtained at step 18
Using P ₀ , the actually set flow rate Q _th of the pump motor 8 corresponding to the detected differential pressure ΔP is calculated by the following equation.

Q _th = Q _tho · ΔP ₀ / ΔP In step 21, it is determined whether the flow rate Q _th is less than the maximum allowable flow rate Q _thMAX of the pump motor 8. Q _th ≧ Q _thMAX
In this case, since the capacity of the pump motor 8 is equal to or more than the capacity limit and the regenerator is insufficient, the routine proceeds to step 37 and the normal braking operation is performed. If Q _th <Q _{th MAX} , step 22
Proceed to.

In step 22, it is determined whether the required braking torque T ₁ by the foot brake is greater than 0. Since the foot brake is not operated when T ₁ = 0, the routine proceeds to step 23, where the third solenoid valve 32 of the air passage 18 is controlled to open. T ₁ > 0
Since the foot brake is being operated at this time, the routine proceeds to step 24, where the open / closed state of the third solenoid valve 32 is judged. If it is in the open state, the routine proceeds to step 25, where the third solenoid valve 32 is controlled to be closed, and if it is in the closed state, it is left as it is.

At step 26, the required braking torque T by the exhaust brake
_It is determined whether ₂ is greater than 0. When T ₂ = 0, the exhaust brake is not operated, so the routine proceeds to step 27, where the fourth solenoid valve 33 of the air passage 28 is controlled to open. When T ₂ > 0, the exhaust brake is being operated, so step 28
Then, the open / closed state of the fourth solenoid valve 33 is determined. If it is in the open state, the routine proceeds to step 29, where the fourth solenoid valve 33 is controlled to be closed, and if it is in the closed state, it is left as it is.

This prevents the deceleration energy from being consumed by a normal foot brake or exhaust brake.

Next, at step 30, the engagement / disengagement state of the engine clutch 2 is determined. If the engine clutch is in the engaged state, the process proceeds to step 31 to perform the disengagement control, and if it is in the disengaged state, it is left as it is. Then, in step 32, it is determined whether the electromagnetic clutch 7 is engaged or disengaged. If the electromagnetic clutch 7 is disengaged, the process proceeds to step 33 to perform connection control. When the connection state is maintained, the pump motor 8 is connected to the wheel drive system to connect the pump motor. 8 is enabled.

At step 34, the flow rate of the pump motor 8 shown in FIG.
From the control current characteristic, the swash plate drive current A corresponding to the pump motor flow rate Q _th set by calculation is obtained and output to the swash plate drive device 42 as a control output.

At step 35, the first and second solenoid valves 9 and 12 provided in the low pressure oil passage 10 and the high pressure oil passage 13, respectively, are controlled to be opened, and at step 36, the fifth solenoid valve 43 is controlled to be closed, so that the pump motor The oil in the low pressure side accumulator 11 is supplied and accumulated in the high pressure side accumulator 14 by 8 to recover the deceleration energy.

On the other hand, in the above-described determination of the predetermined step, when it is determined that the braking operation by the regenerative device is not performed but the normal braking operation is performed, the control from step 37 onward is executed.

That is, in step 37, the open / closed state of the third solenoid valve 32 interposed in the air passage 18 is determined. If it is in the open state, it is left as it is, and if it is in the closed state, the process proceeds to step 38 and the open control is performed, and the process proceeds to step 39.

In step 39, the open / closed state of the fourth solenoid valve 33 interposed in the air passage 28 is determined. If it is in the open state, it is left as it is, and if it is in the closed state, the process proceeds to step 40 and the open control is performed, and the process proceeds to step 41.

In step 41, the connection / disconnection state of the engine clutch 2 is determined. If it is in the connected state, it is left as it is, and if it is in the disconnected state, the process proceeds to step 42 to control the connection and proceeds to step 43.

In step 43, the connection / disconnection state of the electromagnetic clutch 7 is determined. If it is in the disconnection state, it is left as it is, and if it is in the connection state, it proceeds to step 44 to control disconnection and proceeds to step 45.

At step 45, the fifth solenoid valve 43 is controlled to be opened, and at step 46
Then, the first and second solenoid valves 9 and 12 are controlled to be closed.

Thus, at the time of normal brake operation, the air circuit of the normal brake drive system is opened, the pump motor 8 is disconnected from the wheel drive system, the hydraulic circuit of the pump motor 8 is closed, and the operation of the regenerative device is stopped. I am trying to do it.

According to the brake energy regeneration device of the present embodiment,
Since the swash plate angle of the pump motor 8 can be controlled according to the pressure change of the high pressure side accumulator 14, the braking torque required by the driver can be obtained. Therefore, a good driving feeling can be obtained.

In this embodiment, the regenerative device can collect deceleration energy for both the foot brake and exhaust brake operations, but the brake energy recovery effect is greater in exhaust brake operation than in exhaust brake operation. The deceleration energy may be recovered only in response to this.

Further, the connection between the pump motor 8 and the wheel drive system is not limited to this embodiment, but may be connected to the transmission 3 side. In this case, it is necessary to consider the gear ratio of the transmission in calculating the rotation speed of the pump motor.

<Effect of the Invention> As described above, according to the present invention, the swash plate of the swash plate is adjusted so that the pump motor flow rate is inversely proportional to the change in the differential pressure between the high pressure side and the low pressure side of the pump motor. Since the tilt angle is controlled, the braking torque corresponding to the braking force required by the driver can be applied, and the driving feeling can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram for explaining the configuration of the present invention, FIG. 2 is a configuration diagram showing an embodiment of the present invention, FIG. 3 is a flow chart for explaining brake control of the same embodiment, and FIG. 4 is a foot brake. FIG. 5 is a diagram showing the relationship between air pressure and braking torque in the system, FIG. 5 is a diagram showing the relationship between air pressure and braking torque in the exhaust brake system, and FIG. 6 is a difference between pump motor flow rate and braking motor flow rate when braking torque is constant. Figure showing the relationship with pressure, No. 7
FIG. 8 is a diagram showing a pump motor flow rate value corresponding to the braking torque T at a predetermined differential pressure, and FIG. 8 is a diagram showing a relationship between the pump motor flow rate and the swash plate drive current. 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, 32 ... 3rd solenoid valve, 33 ... 4th solenoid Valve, 35 ... control unit, 36 ... vehicle speed sensor, 38-41 ... pressure sensor, 42 ... swash plate drive device, 43 ... fifth solenoid valve

Claims (1)

[Scope of utility model registration request] 1. A brake motor is connected to a wheel drive system of a vehicle when the vehicle is decelerated to operate as a pump, and the oil in the low-pressure side accumulator is pumped into the high-pressure side accumulator to accumulate pressure, thereby recovering brake energy. In the brake energy regeneration device having the configuration, a brake operation detecting means, a hydraulic pressure detecting means for detecting the respective hydraulic pressures of the high pressure side and the low pressure side accumulator, and a brake operation output detecting means for detecting a brake operation output generated by the brake operation, A required braking torque calculation means for calculating a required braking torque based on the output value detected by the brake operation output detection means, and a high pressure side calculated from the calculated value of the required braking torque calculation means and the detected value of the hydraulic pressure detection means. And the pressure difference between the low pressure side and the low pressure side, the flow rate of the pump motor is adjusted to the required braking torque. Brake energy recovery apparatus characterized by comprising a pump motor flow rate control means for controlling.