JPH02117438A - Brake energy recovery and regenerative device for vehicle - Google Patents

Abstract

PURPOSE:To prevent failure such as the malfunction of inclining and rolling angle control due to the interrupted control of a hydraulic circuit in an engine stop condition during hydraulic control by providing a control means for prohibiting the whole control when engine speed is less than idling speed. CONSTITUTION:A hydraulic circuit used in this brake energy recovery and regenerative device is composed of a variable displacement inclined shaft type pump motor 14 engaged with a PTO device 8 through an electromagnetic clutch 13 and combined with an inclining and rolling control magnetic proportional valve 16 and an inclining and rolling angle control piston 17, its suction piping 20, a supply piping 22 and a return piping 22a for hydraulic oil, a circuit change- over valve 25 for changing over high-pressure side and low-pressure side piping 23, 24, and high-pressure and low-pressure accumulators 26, 27. An energy recovery mode or an energy regenerative mode is obtained by controlling the circuit change-over valve 25 through a control means 26, where the whole control is prohibited when the output of an engine speed sensor 35 shows that the engine speed is less the idling speed.

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a brake energy regeneration device for a vehicle that recovers deceleration energy of a vehicle and uses it as starting/acceleration energy.

[Prior art] Of the kinetic energy lost when a vehicle decelerates, the amount that is mainly dissipated as heat (brakes, engine) is recovered as hydraulic pressure and stored in an accumulator, and this stored energy is used as the vehicle's starting energy and PTO (Power-take-of) is used as acceleration energy.
f) A deceleration energy recovery device for a vehicle equipped with an axle equipped with an output device or a transfer has been known for a long time, and the oldest one was developed in 1976 by the British C0J,
It was announced that Lawrence was developing a bus using British Leyland's buses, and since then various research and developments have been carried out in Europe and the United States, and recently, the JP-A-62'
It is disclosed in Japanese Patent Application Laid-open No. 15128, Japanese Patent Application Laid-Open No. 62-37215, and Japanese Patent Application Laid-Open No. 62-39327.

The latter devices both have a countershaft driven via an engine clutch, a main shaft connected to the wheel drive system, and a transmission mechanism that has a multi-stage gear train mechanism that changes the speed and transmits the rotation of the countershaft to the main shaft. (hereinafter abbreviated as T/M), a countershaft PTO gear is attached to the countershaft so that it can communicate with the countershaft via a countershaft PTO gear synchronizer, and a mainshaft PTO gear synchronizer is connected to the main shaft by a gear. A multi-stage variable speed PTOviffi having a main shaft PTO gear mounted so as to be connected to the main shaft PTO gear and a PTO output shaft driven via a drive gear coupled to the main shaft PTO gear.
, a pump motor connected to the PTO shaft, this pump
The hydraulic circuit that connects the accumulator and the oil tank via the motor, and the IA magnetic clutch and electromagnetic clutch that enable this hydraulic circuit to communicate with the PTO shaft, are controlled by the pump.
The Akiemulator, which is connected to the motor through a high-pressure oil circuit, and the pump/motor function as either the pump or the motor depending on the driving condition of the vehicle. By accumulating hydraulic oil in an accumulator through a device, the kinetic energy (hereinafter referred to as brake energy) that is mainly lost as brake and engine heat is recovered, and at the same time when starting/accelerating, the hydraulic oil accumulated in the accumulator is used to rotate the vehicle. The main part is a control means (which functions as a motor that generates force and rotates the wheels via a PTO device).

The control means of such a deceleration energy recovery device is as follows: - At the time of starting, when the hydraulic pressure in the accumulator is sufficient, the capacity of the variable displacement motor (tilt angle of the swash plate or slant shaft) is adjusted according to the amount of depression of the accelerator pedal. At the same time, the electromagnetic clutch is connected and the hydraulic circuit starts using hydraulic pressure.During this time, when the vehicle speed exceeds the set speed corresponding to the gear selected by the driver, the engine clutch is connected and the engine starts driving. At the same time, the system controls the speed change of the PTO device, turns off the countershaft synchronizer that was on, turns on the main shaft synchronizer, and then applies hydraulic pressure according to the amount of depression of the accelerator pedal only when the amount of depression is large at that time. I do.

■When braking, the electromagnetic clutch is connected and a tilt angle control signal (pump capacity control signal) corresponding to the depression of the brake pedal is applied to the pump motor to operate the pump.
At the same time, control is performed to disengage the engine clutch.

In this case, the control means, based on the control program, recovers the amount of braking energy consumed by engine braking, and also disconnects the engine from the wheel drive system when driving by motor, so that the flange of the engine is "disconnected". It is controlled so that the motor and engine are used together, or when starting/accelerating with the engine alone, it is controlled so that it is "contact".

(Problems to be Solved by the Invention) In the case of such conventional technology, there is a problem in which the engine speed drops below the idle speed for some reason during the energy recovery mode, energy regeneration mode, or normal brake control mode. Since the control continues even when the engine is not started (including when the engine has not started), for example, in the case of energy recovery mode, the hydraulic oil pressure from the pressurized tank decreases, and there is a risk that cavitation may occur in the hydraulic circuit. There is.

In addition, if the engine stops while driving (including when stopped) or when the engine is not started, pilot pressure is not generated by the charge pump, so tilting control of the pump/motor and hydraulic oil supply to the closed circuit by the charge pump are prevented. There was a problem that it became impossible to replenish supplies.

Therefore, an object of the present invention is to realize a brake energy regeneration device for a vehicle that can inhibit all hydraulic-related controls when the engine speed becomes equal to or lower than the idle speed.

[Means to solve the problem]

In order to achieve the above object, the present invention includes a hydraulic circuit;
The engine includes an engine rotation speed sensor and a control means for prohibiting all control when the engine rotation speed is equal to or lower than the idle rotation speed.

[Function] In the present invention, the control means constantly monitors the output of the engine rotation speed sensor and detects when the engine rotation speed becomes equal to or lower than the idle rotation speed, and at this time all controls including hydraulic circuit control are activated. Stop the process.

As a result, the hydraulic circuit does not work, so cavitation does not occur in the pump, and tilting angle control of the pump/motor and replenishment of hydraulic oil by the charge pump do not become impossible during hydraulic control.

[Embodiment] FIG. 1 is an overall configuration diagram of an embodiment of a brake energy regeneration device for a vehicle according to the present invention, in which 1 is an engine, 2
3 is a step motor that responds to the depression of the accelerator pedal 54; 4 is a step motor 3;
5 is an injection pump lever that is controlled by and sets the amount of fuel supplied to the engine 1 and is connected to the load sensor 2; 5 is a T/M (transmission) that changes the speed of the engine 1 and outputs it; 6 is a gear shift actuator that automatically shifts the gear stage (not shown) of T/M5, 7 is a clutch actuator that automatically engages a clutch (not shown), and 8 is engaged with T/M5. A PTO device, 9 is a propeller shaft forming a wheel drive system together with the axle 10 and wheels 11, 12 is a PTO shaft of the PTO device 8, 13 is an electromagnetic clutch, and 14 is a PTO device r via the PTO shaft 12 and the electromagnetic clutch 13.
i! Pyro for tilting angle control engaged with 8.7) Piping 1
5. A well-known variable displacement inclined shaft type axial piston pump/motor combined with a tilt angle control electromagnetic proportional valve 16 and a tilt angle control piston 17, 14a is its inlet port;
14b is a discharge port. Also, 80 is the pump motor 1
This is a tilt angle sensor that detects the tilt angle of 4.

Here, regarding this pump motor 14, see FIG. 2(a).
2(a), which is a view in the direction of arrow A in FIG. 2(a), as shown in FIG. 2(a), the output shaft 14c is engaged with the center hole of the cylinder block 14f. A shaft 14d is inserted thereinto, and the opposite side of the shaft 14d is engaged with the tilt angle control piston 17 via a boat plate 14h. Also, around this cylinder block 14f? ! A piston 14e engaged with an output shaft 14c is slidably inserted into one end of the cylinder 14g, and a piston 14e engaged with an output shaft 14c is slidably inserted into one end of the cylinder 14g. Inlet port 14 shown in Φ)
a or the discharge port 14b.

The above-mentioned tilting angle control piston 17 is connected to a hydraulic oil or hydraulic pipe 20 that is supplied to the lower part of the piston 17 from a pilot pipe 915 for tilting angle control in proportion to the control current supplied to the tilting angle control electromagnetic proportional valve 16. Or, by being pushed by the hydraulic oil in 21, its position changes in the vertical direction in the figure. Therefore,
Cylinder block 14f, piston 14e, shaft 1
4d and the boat plate 14h, the angle changes as the tilt angle control piston 17 moves up and down around the spherical end of the shirt 14d engaged with the output shaft 14c (in this case, the angle changes between the output shaft 14C and the boat plate 14h). shirt) 14d
The angle θ formed by these is called the tilt angle).

FIG. 2(a) shows the case when the maximum control current is applied to the tilting angle control electromagnetic proportional valve 16, and since the tilting angle is the maximum, the discharge amount per revolution of the output shaft 14c is the maximum. It has become. When the control current of the tilting angle control electromagnetic proportional valve 16 is O, the tilting angle becomes O and the discharge amount also becomes 0, as shown by the dotted line.

Returning to FIG. 1, 18 is a high pressure accumulator 26, which will be described later.
19a is a high-pressure relief valve that releases the accumulated pressure when it exceeds a set value, 19a is a low-pressure relief valve that releases the hydraulic oil supply pressure in the supply circuit when it exceeds a set value, and 19b is a pilot for controlling the tilting angle. In the piping 15, a low pressure relief valve that generates the Byront pressure necessary to operate the pump/motor 14 in a tilting manner; 20 is a suction side piping of the pump/motor 14;
21 is the discharge side piping of the pump/motor 14, 22 is the hydraulic oil supply piping, 22a is the hydraulic oil return piping, 23 is the high pressure side piping, 24 is the low pressure side piping, and 25 is the above piping 20 to 24.
26 is a high pressure accumulator that is connected to the circuit switching valve 25 via the high pressure side piping 23; 27 is a high pressure accumulator that is connected to the circuit switching valve 25 via the low pressure side piping 24 and is connected to the pump/motor 14, the circuit This is a low-pressure accumulator that forms a hydraulic circuit together with the switching valve 25 and the high-pressure accumulator 26.

Note that the circuit switching valve 25 is necessary to switch the output between pump and motor when the pump/motor 14 is used with a fixed outlet. If a motor is used, a circuit isolation valve can also be used. These circuit switching valves and circuit cutoff valves can be collectively referred to as circuit valves.

Here, to explain the switching operation of the piping by the circuit switching valve 25, when neither of the Tf and m stones 25a and 25b is energized, the valve position is the position shown in the center of the three valve positions. As a result, the four pipes 20, 21, 23 and 24 are disconnected.

When recovering brake energy, the electromagnet 25a
is energized to switch the valve position to the electromagnet 25a side. Then, the low pressure accumulator 27 can be communicated with the suction port 14a of the pump motor 14 via the pipes 24 and 20, and the high pressure accumulator 26 can be communicated with the discharge port 14b of the pump motor 14 via the pipes 23 and 21. . As a result, the hydraulic fluid stored in the low-pressure accumulator 27 is sucked/discharged by the pump/motor 14 that is driven by brake energy and functions as a pump, and the pressure is accumulated in the high-pressure accumulator 26 .

On the other hand, when the pump motor 14 is to function as a motor, the electromagnet 25b of the circuit switching valve 25 is energized and the valve position is switched to the electromagnet 25b side.

Then, the low pressure accumulator 27 can be communicated with the discharge port 14b of the pump motor 14 via the pipes 24 and 21, and the high pressure accumulator 26 can be communicated with the suction port 14a of the pump motor 14 via the pipes 23 and 20. As a result, the hydraulic oil accumulated in the high-pressure accumulator 26 passes through the pipes 23 and 20 to the pump motor 1.
4 as a motor, it passes through the pipes 21 and 24 and reaches the low pressure accumulator 27, where it is stored.

28 is a drain tank for hydraulic oil, 29 is a filter for hydraulic oil, 30 is a replenishment pump for hydraulic oil driven by the engine 1, and 31 and 32 are provided on the replenishment pipe 22 and are operated to return from the hydraulic circuit to the drain tank. This is a solenoid valve that supplies oil to the hydraulic circuit and also supplies pilot hydraulic pressure to the pump/motor 14 via a tilt angle control pilot pipe 15.

Next, 33 is a direct connection cooling relay switch, 34 is a water temperature sensor for engine l, 35 is a rotation speed sensor for engine l, 3
6 is input shaft rotation speed sensor, 37 is 77M5
38 is a clutch stroke sensor, 38 is a gear position sensor,
39 is a gear shift stroke sensor, 40 is a vehicle speed sensor, 41 is a 77M5 oil temperature sensor, 42 is an exhaust brake control valve, 43 is a cylinder that drives an exhaust brake valve (not shown), and 44 is a cylinder that drives an exhaust brake control valve (not shown). 45 and 46 are oil amount detection limit switches provided in the drain tank 28, and 47 is a pressure sensor that detects the pressure of the hydraulic oil accumulated in the high pressure accumulator 26. Note that the gear position sensor 38 and the gear shift stroke sensor 39 constitute gear position detection means.

48 is a hand lever that operates the exhaust brake, 49 is a driver seat, 50 is an vacated seat detection switch that detects whether or not the driver has left the driver seat 49, 51 is a parking brake lever, and 52 is a parking brake inch. , 53 is a brake energy regeneration system (hereinafter referred to as RBS) main switch, 54
is the accelerator pedal, 55 is the idle position detection switch,
56 is an accelerator distance detection sensor, 57 is a brake pedal, and 5th is a brake pedal return position detection switch (hereinafter referred to as
59 is a brake depression amount sensor, 60 is a gear select lever, 61 is a hill start assist device (hereinafter abbreviated as ISA) switch,
62 is an idle control switch, 63 is an indicator, 65 is a door switch, 66 is a key switch, 6
7 is brake air piping, 68 is brake air tank, 6
9 is a brake air pressure sensor, 70 is an electromagnetic proportional pressure control valve, 71 and 73 are air pressure switches, and 72 is an I(S
Valve A, 74 is an air mask, and 64 is a control unit (hereinafter abbreviated as C/U) as a control means that controls the pump/motor 14 and actuator to regenerate brake energy based on the outputs of the above-mentioned sensors and switches, etc. The C/U 64 includes a memory (not shown) that stores the programs, maps, and flags described below.
Contains.

FIG. 3 is a flowchart of a program stored and executed in the C/1J64 shown in FIG. 1, and the operation of the embodiment shown in FIG. 1 will be explained based on this flowchart.

When the program starts, the C/U64 executes an initialization subroutine, turns off all outputs, and uses the built-in RAM.
A clear check (not shown) is performed (step St in FIG. 3).

After performing the initialization, switch 33.45.46 mentioned above
．． 50.52.53.55.58.61.62.65.
A subroutine for reading signals from sensors 66, 71 and 73 and the sensor 38 is executed (step S2), and then a subroutine for processing rotational signals (pulses) read from sensors 35, 36 and 40 is executed to determine the engine rotational speed, respectively. Calculate input shaft rotation speed and vehicle speed (
same step S3).

And sensor 2.34.37.39.41.47.5
Execute the analog signal processing subroutine read from 6.59.69 to obtain the digital values of engine load, clutch stroke, shift stroke, oil temperature, pressure, accelerator opening, brake depression amount, and brake air pressure. Step S4).

Reading and processing of these signals are updated every time C/U processing is performed. Also, read signals and processing (during control history,
(excluding flags that are set/reset).

Next, it is checked whether the key switch 66 is on or not (step S5), and if it is off, the entire control stop subroutine is executed (step 36).

In this subroutine, in order to ensure safety even if the key switch 66 is turned off when stopping or driving, the entire hydraulic system is returned to a safe state, and then, in step S7, the actuator relay (not shown) is turned off and the All control is stopped by cutting off the power to /U64.

When the key switch 66 is on in step S5,
Check whether the RBS main switch 53 is on or not (step S8 in FIG. 3). If it is off, execute the normal brake control mode subroutine (step S8 in the same figure), which will be described later.
22) is on, it is assumed that the driver is attempting to perform a brake energy regeneration system (hereinafter referred to as RBS) operation, and control continues.

Therefore, C/l, 164 checks whether or not the driver is operating the parking brake 51 (step S9), and when not operating (when the parking brake switch 52a (P/Bl) is off). ), the RBS is enabled and the process proceeds to step S11, but when it is activated (the parking brake switch 52a is on), the process proceeds to the normal brake control mode (step 522) and the use of the RBS is prohibited. This is to prevent the vehicle from jumping out even if the accelerator pedal 54 is inadvertently depressed while the parking brake lever 51 is being pulled.

However, another parking brake switch 5 is installed in case the output torque of the pump/motor 14 is transmitted to the wheels 11 while the parking brake is activated, such as when starting on a slope.
Check whether 2b is on (step 510)
It is preferable.

Here, the parking brake switch 52b (P/B2
) is turned on only when the knob 51a of the parking brake lever 51 is pressed, as shown in FIG. That is, since the state in which the knob 51a is pressed indicates the intention to release the parking brake, the RBS can be used even if the parking brake lever 51 is pulled and the parking brake switch 52a is on. It is.

Next, the C/U 64 checks the selected gear using the gear position detection sensor 38 and the gear shift stroke sensor 39 (S11), and the gear is set to N.
If the gear position is neutral) or R (reverse), the process proceeds to the normal brake control mode subroutine (step 522) without using RBS, but if the gear is 1st to 5th gear, R is selected.
The BS continues to take control because it is available.

Then, it is checked from the output of the vehicle speed sensor 40 whether the vehicle is stopped (step 512), and if the vehicle is traveling, the process proceeds to step S14 and the current speed of the pump motor 1 is checked.
Check whether it corresponds to the allowable rotation speed of 4 or less. This allowable rotational speed is determined by the pump motor 14 and the electromagnetic clutch 1
3, PTO shaft 12, PTO device 8, propeller shaft 9
Since the gear ratio of the PT○ device 8 and the axle IO is constant, it can be determined by the vehicle speed, and the gear ratio can be determined from the allowable rotation speed of the commercially available pump/motor 14. , and the outside wheel PiI length, it can be determined that the usable range of the RBS is, for example, up to 50 km/h.

In step 314, if the vehicle speed is 50 km/h or less, that is, within the permissible rotation speed range of the pump motor 14,
Control is continued, but when it is determined that the number of rotations exceeds the allowable rotation speed range, the normal brake control mode subroutine of step S22 is executed.

In step 312, when the vehicle is stopped and the vehicle is a bus, a start prohibition subroutine is executed (step 513). This subroutine prohibits the use of the hydraulic circuit when the bus door is open. When the door is open, it is assumed that passengers are getting on and off, and careless operation is performed to ensure the safety of the passengers. This is done to prevent the vehicle from moving even if the accelerator is pressed.

Next, the C/U 64 checks the driver's pedal operations in the order of brake (step 515) and accelerator (step 516) (each signal processing has already been processed in the analog signal processing subroutine of step S4). The reason why the brake operation check is given priority over the accelerator operation check is that when the brake pedal 57 and the accelerator pedal 54 are depressed at the same time, the brake is prioritized for vehicle safety.

If the brake pedal 57 is depressed in step 315, an energy recovery mode subroutine is executed (step 517). When the brakes are often used at low speeds such as during traffic jams, the hydraulic system is controlled more frequently, so in order to avoid using hydraulic pressure, the system responds to the amount of depression of the brake pedal 57 only when the vehicle speed is within a certain range. The required brake torque is determined by To find the brake torque in this case, a control torque search is performed using the brake torque map shown in FIG. 5, and the braking torque that the driver is trying to generate is searched and stored based on the amount (angle) of depression of the brake pedal 57.

After running the energy recovery mode subroutine, C/
U64 executes an engine brake mode subroutine (step 31B in FIG. 3).

This subroutine is intended to eliminate the difference in feeling from a normal vehicle, that is, to generate a braking force equivalent to exhaust braking or engine braking.

The exhaust brake is an auxiliary brake that is operated by the hand lever 48 (or switch) on the driver's seat without stepping on the brake pedal 57.The engine brake is an auxiliary brake that is operated by the hand lever 48 (or switch) on the driver's seat. This is an auxiliary brake that generates

To the subroutine of step 318, the brake pedal 5
If the accelerator pedal 54 is not depressed (when the accelerator pedal is in the idle position), the process proceeds from step S16. Since step 318) in the figure is a substitute mode for the auxiliary brake generated by the engine, it has no relation to the brake pedal operation in step S17 in FIG. 3. That is, as long as the accelerator pedal 54 is not depressed, both the exhaust brake and the engine brake are controlled by the output of the hand lever 48, and alternative forces are generated. In other words, when the braking force corresponding to the amount of depression of the brake pedal is determined, if the vehicle is traveling at a certain speed or higher, the braking torque equivalent to the exhaust brake or engine brake is determined.

Subsequently, the C/U 64 determines the capacity of the pump/motor 14 necessary to generate the necessary control torque retrieved and stored in the subroutines of step S17 and step 31B in accordance with the pressure in the hydraulic circuit. A calculation subroutine is executed (step 519 in FIG. 3).

That is, if hydraulic brake control using the pump/motor 14 is performed in steps S17 and 318 described above, the required braking torque for each brake mode searched in steps S17 and S18 is integrated and generated by the pump/motor 14. Calculate the total control torque required.

Then, the capacity ffi VP of the pump motor 14 is determined by the following theoretical formula (1) from the torque value T at the pump motor I4, which is obtained by dividing the required torque value by the gear ratio of the final gear and the Pro device.

Vp -200πT/P (1) Here, P: Pressure in the hydraulic circuit detected by the pressure sensor 47 (kg
/cm”), (P): Capacity 1 (cc) of the pump/motor 14, T: Required control torque (kg g-m).

In the present invention, as shown in FIG.
Since a pump motor 14 can be used, its volume MVP is controlled by controlling the tilt angle of the slant shaft (or swash plate).

Returning to step 316 of the main program, when accelerator pedal 54 is depressed, C/U 64 executes an energy regeneration mode subroutine (step 520 of FIG. 3). This subroutine runs by utilizing the energy recovery and deceleration energy stored in the high-pressure accumulator 26, but by searching the map shown in Figure 6, it determines the amount of accelerator pedal depression at that time. This is a routine to calculate the required torque and write it down.

Then, the main program executes the normal brake control mode subroutine of Stenbu S22, but this turns the hydraulic circuit into an oven so that no hydraulic pressure is used, and only the air brake or air/oil brake is applied depending on the amount of depression of the brake pedal. This is the mode where the brakes are applied.

After the above control, the C/U 64 performs oil amount control i11 (step 521 in FIG. 3). In this oil amount control, it is determined whether or not oil needs to be replenished based on whether the oil amount detection limit switch 45 is on or off, and the solenoid valves 31 and 32 always supply an appropriate amount of oil to the hydraulic system. supplying.

The C/U 64 also receives a vehicle speed signal from a vehicle speed sensor 40, a signal corresponding to the amount of depression of the accelerator pedal 54 from an accelerator opening detection sensor 56, and a gear select lever, as in the well-known Japanese Patent Application Laid-Open No. 60-11769. The select signal (matrix signal) from 60 is read, and an appropriate gear stage of 77M5 is selected according to the vehicle speed and the amount of depression of the accelerator pedal 54 (steps S23 and 524 in FIG. 3).
.

This operation is performed by driving the clutch actuator 7 and gear shift actuator 6, disengaging the engine clutch (not shown) → setting the T/M5 gear to neutral → selecting and shifting → connecting the engine clutch. As a result, the gear stage of the T/M5 is automatically shifted down to an appropriate gear according to the vehicle speed and the amount of depression of the accelerator pedal 54.

Also, based on the clutch control method determination subroutine (step 24 in FIG. 3), the C/U 64 always performs an engine clutch in the energy recovery mode, and in the energy regeneration mode, when the vehicle is driven only by hydraulic pressure. is strictly prohibited.

Furthermore, automatic clutch-type automatic transmission vehicles are already known for engine clutch engagement/disengagement control.
Furthermore, even if the vehicle does not have an automatic transmission, only the engine clutch needs to be able to automatically engage/disengage.Furthermore, in the case of vehicles with a hydraulic automatic transmission, disconnection from the engine can be achieved by controlling the gear to the neutral position. A similar effect can be obtained.

Next, the capacity of the pump/motor 14, the disconnection/connection of the electromagnetic clutch 13, and the circuit switching valve 2 determined in the above-mentioned energy recovery mode, regeneration mode, normal brake control mode, etc.
5, a hydraulic circuit control subroutine for actually driving these is executed (step 525 in FIG. 3).
).

This subroutine detects the above various judgment results and controls the circuit switching valve 25 and pump/motor 14 that constitute the hydraulic circuit.
It also actually controls the electromagnetic clutch 13.

After performing hydraulic circuit control (step 525), signals from the direct cooling relay switch 33 and water temperature sensor 34 are read, and in addition to stabilizing the idle rotation during warm-up and cooling of the engine 1, the replenishment pump 30 An idle control subroutine is executed to stabilize the idle rotation when driving the engine (step 526).

Thereafter, the target position of the step motor 3 is set using the output torque of the engine 1 determined in the above-mentioned energy regeneration mode, etc., and an engine control subroutine for driving the step motor 3 is executed (step 527). Pump motor 14 determined by regeneration mode etc.
When the capacity ■ is V<250cc, it is idling,
When V>250cc, the engine is controlled so that the required engine output obtained from the following equation (2) is generated.

Required engine output = ((T/M required output) - (maximum pump/motor output) It is obtained by converting the fuel injection governor into a step motor and driving the fuel injection governor.

After the above control/processing, an indicator control subroutine for controlling the display of the indicators 63 including oil pressure and power FA (oil pressure, engine) display is executed (step 828).

Then, on condition that the vehicle speed is O and the brake pedal 57 is depressed, the H3A valve 72 is closed to maintain the brake state, and when the accelerator pedal 54 is depressed or the gear select lever 60 is moved to the neutral position. l5AIII? 1 subroutine is executed (step 529).

After this, check whether it is time to execute the self-diagnosis (step 530), and when the time comes, execute the self-diagnosis periodically (for example, every 500 m5) (step 53).
1) After waiting for a period of time to make the processing time constant (step 532), the process returns to step S2 and repeats the above-described process.

Incidentally, the above-mentioned subroutine (steps S23 to S31) can use a technique known to date.

Control of the present invention in the vehicle brake energy regeneration device described above will be explained.

The control flow shown in FIG. 7 is executed by constantly reading the output of the engine rotation speed sensor 35 and monitoring the output by the C/U 64 using the free time in one cycle of the control flow shown in FIG. Assuming that the engine rotational speed is N, the average value N of the previous engine rotational speed N, . . . (which is initially set to O) is calculated (step 5IOI).

Compare this average value N with the idle rotation speed Nl0L (step 3102), and if N≧N1°, flag FL-
In addition to resetting RBS to '0'' (step 5103), flag FL RB is set when N, kuN, .
Set S to "1" (Step 5104), and set the average value N1 obtained in Step 5101 to the previous engine rotation speed N.
It is stored as t-+ (step 5105).

In this way, the flag FL-RBS is set/reset, and as shown in FIG.
Flag FL R as each front stem of t~S29
By determining whether the BS is set or reset (step 5Lto), the flag FL
When RBS is set, for example, all steps (not shown) in the energy regeneration mode subroutine S2Q are skipped, and when RBS is reset, subroutine S20 is executed. this is,
The other subroutines mentioned above are performed in exactly the same manner.

As a result, when the engine speed falls below the idle speed, all control steps including the hydraulic circuit are prohibited, and in particular, even if the replenishment pump 30 is almost stopped, the pump/motor tilt angle control, There is no problem that the supply of hydraulic oil to the closed oil circuit is interrupted during control.

【Effect of the invention〕

As described above, according to the present invention, all control is prohibited when the engine speed is less than the idle speed, so that interruption in the middle of the control of the hydraulic circuit due to the engine stop state that occurs during the hydraulic control is particularly effective. It is possible to avoid problems caused by this (insufficient tilt angle control, insufficient hydraulic oil replenishment).

[Brief explanation of drawings]

FIG. 1 is a diagram showing the configuration of an embodiment of the vehicle brake energy regeneration device according to the present invention, and FIG.
3 is a flowchart of a program stored and executed in the control means of the present invention; FIG. 4 is a schematic diagram illustrating the parking brake lever; FIG. 5 is a brake torque map diagram, FIG. 6 is a torque map diagram for each gear stage, and FIG. 7 is a flowchart diagram for interrupting the C/U in order to detect an engine speed defect according to the present invention. FIG. 8 is a flowchart for inhibiting execution of each subroutine according to the present invention. In the figure, 8 is a PTO device, 13 is an electromagnetic flanch, 1
4 is a pump motor, 25 is a circuit switching valve, 26 is a high pressure accumulator, 27 is a low pressure accumulator, 35 is an engine rotation speed sensor, and 64 is a C/U as a control means. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. A brake energy regeneration device for a vehicle, comprising a hydraulic circuit, an engine rotation speed sensor, and a control means for prohibiting all control when the engine rotation speed is less than or equal to an idle rotation speed.