JPH0764251B2 - Vehicle brake energy regeneration device - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a braking energy regeneration device for a vehicle that recovers deceleration energy of the vehicle and uses it as start / acceleration energy.

[Conventional technology]

Of the kinetic energy that is lost when the vehicle decelerates, the amount that is dissipated (brake, engine) mainly as heat is collected as operating hydraulic pressure and accumulated in the accumulator, and this accumulated energy is used as the starting energy and acceleration energy of the vehicle. BACKGROUND ART A deceleration energy recovery device for a vehicle equipped with a PTO (Power-take-off) output device or an axle equipped with a transfer has been known for a long time. The oldest was CJ Lawrence of England in 1976 when a British Leyland bus was used. Since it was announced that it is under development, various researches and developments have been carried out in Europe and the United States, and recently, JP-A-62-15128 and JP-A-62-372.
No. 15 and JP-A No. 62-39327, and the like.

Each of the latter devices is a transmission having a multi-stage gear train mechanism that shifts and transmits the rotation of a counter shaft driven through an engine clutch, a main shaft connected to a wheel drive system, and the counter shaft to the main shaft. , T / M), the counter shaft PTO gear mounted on the counter shaft so that it can be connected and disconnected via the counter shaft PTO gear synchronizer, and this PTO gear is gear-coupled to the main shaft PTO main shaft PTO.
A multi-stage transmission PTO device having a main shaft PTO gear that is detachably mounted via a gear synchronizer and a PTO output shaft that is driven through a drive gear that is connected to this main shaft PTO gear. Connected pump / motor, hydraulic circuit that connects the accumulator and oil tank via this pump / motor, electromagnetic clutch that enables and disconnects this hydraulic circuit and PTO shaft, and the pump / motor that controls the electromagnetic clutch. The accumulator and pump / motor connected by the high-pressure oil circuit are made to function as either one of the pump and the motor depending on the operating condition of the vehicle (that is, they function as a pump at the time of deceleration, and the rotational force of the wheels causes the PTO device to operate. Kinetic energy lost mainly as brake and engine heat by accumulating hydraulic oil in the accumulator (below Generates a rotational force by the hydraulic fluid when starting / acceleration which has been accumulated in the accumulator is recovered is referred to as brake energy) PTO
A control unit that functions as a motor that rotationally drives the wheels through the device) is configured as a main part.

Such control means of the deceleration energy recovery device controls the capacity of the variable displacement motor (the tilt angle of the swash plate or the swash shaft) according to the amount of depression of the accelerator pedal when the vehicle starts and when the hydraulic pressure in the accumulator is sufficient. Controlling and connecting an electromagnetic clutch to start by hydraulic pressure by a hydraulic circuit, and when the vehicle speed set corresponding to the gear selected by the driver is exceeded during that time, the engine clutch is connected to drive the engine. Perform the shift control of the PTO device, turn off the counter shaft synchronizer that was on and turn on the main shaft synchronizer, and only when the accelerator pedal depression amount at that time is large, control to apply hydraulic pressure according to that depression amount To do.

During braking, the electromagnetic clutch is connected and the tilt angle control signal (pump displacement control signal) according to the depression of the brake pedal is applied to the pump / motor to perform pump operation.
At the same time, control is performed to disengage the engine clutch.

In this case, the control means collects the portion of the braking energy consumed by the engine brake based on the control program, and disconnects the engine from the drive system of the wheels during traveling by the motor. In addition to the control so that the motor and the engine are used together, or when the vehicle is started / accelerated only by the engine, the control is performed so as to be “contact”.

[Problems to be Solved by the Invention]

In the case of such a conventional technique, as long as the vehicle speed is not 0 and the brake pedal is depressed, the hydraulic brake operation by the pump / motor is always performed, but only the hydraulic brake and / or the engine brake is applied, When the hydraulic brake torque is less than the required brake torque, no measures have been taken. Therefore, there is a problem that sufficient braking force cannot be generated when the amount of depression of the brake pedal is large.

Therefore, it is an object of the present invention to realize a braking energy regeneration device for a vehicle that can always generate a required braking force.

[Means for Solving the Problems]

In order to achieve the above object, the present invention uses a low pressure accumulator (electromagnetic clutch and PT) during deceleration energy recovery.
O equipment and any of the usual drive systems such as axles)
When the energy is stored in the high pressure accumulator via the pump / motor and the circuit valve connected to the power branch mechanism and the stored energy is regenerated, the high pressure accumulator is transferred to the low pressure accumulator via the circuit valve and the pump / motor. The maximum displacement is the hydraulic circuit that releases hydraulic pressure, the brake pedal switch, the air pressure control valve, the air brake device, and the pump capacity of the pump / motor of the hydraulic circuit that is obtained from the memory map according to the required total braking torque. Control means for maximizing the pump displacement to operate the hydraulic circuit when the switch is operating, and to supplement the insufficient braking torque with the air brake device by controlling the control valve when the switch is operating. And are equipped with.

[Action]

The present invention will be described with reference to the schematic view of FIG. 1 (a). The control means (C / U) 64 determines the hydraulic circuit (high pressure accumulator 26, circuit valve 25, pump / motor 1) from the required total braking torque.
4. Comprised of low-pressure accumulator 27) and the pump capacity of the pump motor 14 during braking is determined.

When the pump capacity exceeds the maximum capacity of the pump / motor, the control means 64 performs control to fix the pump capacity of the pump / motor 14 to the maximum and applies the hydraulic brake by the hydraulic circuit as shown in the figure. At this time, if the brake pedal 57 is depressed and the brake pedal switch 58 is operating, the brake torque due to the maximum pump capacity is subtracted from the required total brake torque to obtain the insufficient brake torque. By controlling the air pressure control valve 70, it is generated in the air brake device to compensate.

Therefore, the shortage of the braking force by the hydraulic circuit can be supplemented by the air braking force.

[Examples] Examples of a vehicle brake energy regeneration device according to the present invention will be described below.

FIG. 1 (b) is an overall configuration diagram of an embodiment of a vehicle brake energy regeneration device according to the present invention, in which 1 is an engine, 2 is a load sensor of the engine 1, and 3 is an accelerator pedal.
A step motor 4 responding to the depression of 54 sets the fuel supply amount to the engine 1 under the control of the step motor 3 and an injection pump lever 5 connected to the load sensor 2 changes the rotation speed of the engine 1. T / M (transmission) to be output as a gear, 6 is a gear shift actuator that automatically shifts a gear stage (not shown) of T / M5, and 7 is a clutch actuator that automatically disconnects a clutch (not shown). , 8 are engaged with T / M5
A PTO device, 9 is a propeller shaft that forms a drive system for the wheel together with the axle 10 and the wheels 11, and 12 is a PTO of the PTO device 8.
Shaft, 13 is electromagnetic clutch, 14 is PTO shaft 12 and electromagnetic clutch 1
A well-known variable displacement oblique shaft type axial piston which is engaged with the PTO device 8 through 3 and is combined with the tilt angle control pilot pipe 15, the tilt angle control solenoid proportional valve 16 and the tilt angle control piston 17. A pump / motor, 14a is its suction port, and 14b is its discharge port. Also, 80 is the pump / motor 14
Is a tilt angle sensor that detects the tilt angle of the.

Here, the pump / motor 14 will be described with reference to FIG. 2 (a) and FIG. 2 (b), which is a view taken in the direction of arrow A in FIG. 2 (a), as shown in FIG. 2 (a). The shaft 14 that engages with the output shaft 14c in the center hole of the cylinder block 14f
d is inserted, the other side is port plate 14h
It is engaged with the tilt angle control piston 17 via. Also,
Around the cylinder block 14f, multiple cylinders 1
4g is provided, a piston 14e engaged with the output shaft 14c is slidably inserted into one end of the cylinder 14g, and the opposite side is shown in FIG. 2 (b) via a port plate 14h. It communicates with the suction port 14a or the discharge port 14b shown.

The tilt angle control piston 17 described above is a tilt angle control solenoid proportional valve.
By being pushed by the hydraulic oil supplied to the lower part of the piston 17 from the tilting angle control pilot pipe 15 or the hydraulic oil in the hydraulic pipe 20 or 21 in proportion to the control current supplied to 16, the position is moved up and down in the figure. Change direction. Therefore, the assembly composed of the cylinder block 14f, the piston 14e, the shaft 14d and the port plate 14h has a tilt angle control piston 17 centered on the spherical end of the shaft 14d engaged with the output shaft 14c.
The angle changes with the vertical movement of (in this case, the output shaft 14
The angle θ formed by c and the shaft 14d is called the tilt angle).

FIG. 2 (a) shows the case where the maximum control current is applied to the tilt angle control solenoid proportional valve 16, and the tilt angle is the maximum, so the discharge amount per revolution of the output shaft 14c is the maximum. Has become. When the control current of the tilt angle control solenoid proportional valve 16 is 0,
As shown by the dotted line, the tilt angle is 0 and the discharge amount is also 0.

Returning to FIG. 1 (b), 18 is a high pressure accumulator described later.
High pressure relief valve that releases the accumulated pressure of 26 when it exceeds the set value, 19a is a low pressure relief valve that releases it when the supply pressure of the hydraulic oil in the replenishment circuit exceeds the set value, and 19b is for tilt angle control In the pilot pipe 15, a low-pressure relief valve that generates the pilot pressure required to tilt the pump / motor 14, 20 is the suction side pipe of the pump / motor 14, 21 is the discharge side pipe of the pump / motor 14, 22 Is hydraulic oil supply pipe, 22a
Is a hydraulic oil return pipe, 23 is a high pressure side pipe, 24 is a low pressure side pipe, 25 is a circuit switching valve that switches the above pipes 20 to 24, 26
Is a high pressure accumulator connected to the circuit switching valve 25 via the high pressure side pipe 23, 27 is connected to the circuit switching valve 25 via the low pressure side pipe 24, and the pump / motor 14 and the circuit switching valve 25 are connected.
And a low pressure accumulator forming a hydraulic circuit with the high pressure accumulator 26.

The circuit switching valve 25 is necessary to switch the output between the pump and the motor when the inlet / outlet of the pump / motor 14 is fixed and is used. If a motor is used, a circuit shutoff valve can also be used. These circuit switching valve and circuit cutoff valve can be collectively referred to as a circuit valve.

Here, the switching operation of the piping by the circuit switching valve 25 will be described. When neither of the electromagnets 25a and 25b is energized, the valve position becomes the position shown in the center of the three valve positions and the four valve positions are set. The pipes 20, 21, 23 and 24 are disconnected.

When recovering the brake energy, the electromagnet 25a is energized to switch the valve position to the electromagnet 25a side. Then,
Pump low-pressure accumulator 27 through pipes 24 and 20.
The high pressure accumulator 2 is connected to the suction port 14a of the motor 14.
6 through the pipes 23 and 21 to the discharge port 14b of the pump / motor 14.
Can be connected to. As a result, the hydraulic oil stored in the low pressure accumulator 27 is sucked / discharged by the pump / motor 14 that is driven by the brake energy and functions as a pump, and is stored in the high pressure accumulator 26.

On the contrary, when the pump / motor 14 is to function as a motor, the electromagnet 25b of the circuit switching valve 25 is energized to switch the valve position to the electromagnet 25b side. Then, the low pressure accumulator 27
Can be connected to the discharge port 14b of the pump / motor 14 via the pipes 24 and 21, and the high-pressure accumulator 26 can be connected to the suction port 14a of the pump / motor 14 via the pipes 23 and 20. As a result, the hydraulic oil stored in the high pressure accumulator 26 passes through the pipes 23 and 20 to rotate the pump / motor 14 as a motor, and then reaches the low pressure accumulator 27 through the pipes 21 and 24, where it is stored. become.

28 is a hydraulic oil drain tank, 29 is a hydraulic oil filter,
30 is a hydraulic oil supply pump driven by the engine 1,
31 and 32 are provided on the replenishment pipe 22 to supply the hydraulic oil returned from the hydraulic circuit to the drain tank to the hydraulic circuit, and also to the pump / motor 14 through the tilt angle control pilot pipe 15 to supply the pilot hydraulic pressure. It is a solenoid valve.

Next, 33 is a direct cooling relay switch, 34 is a water temperature sensor for the engine 1, 35 is a rotation speed sensor for the engine 1, 36 is an input shaft rotation speed sensor, 37 is a clutch stroke sensor for T / M5, and 38 is a gear position sensor. , 39 is a gear shift stroke sensor, 40 is a vehicle speed sensor, 41 is a T / M5 oil temperature sensor, 42 is an exhaust brake control valve, 43 is a cylinder for driving an exhaust brake valve (not shown), and 44 is an exhaust brake control valve.
Air piping to supply air pressure to the cylinder 43 via 42, 45
And 46 are oil amount detection limit switches provided in the drain tank 28, and 47 is a pressure sensor for detecting the pressure of the hydraulic oil accumulated in the high pressure accumulator 26. The gear position sensor 38 and the gear shift stroke sensor 39 form a gear position detecting means.

Then, 48 is a hand lever for activating the exhaust brake, 49 is a driver seat, 50 is a leaving seat detection switch for detecting whether or not the driver has left the driver seat 49, 51 is a parking brake lever, 52 is a parking brake switch, 53 is a brake energy regeneration device (hereinafter referred to as RBS) main switch, 54 is an accelerator pedal, 55 is an idle position detection switch, 56 is an accelerator opening detection sensor, 57 is a brake pedal, 58 is a brake pedal return position detection switch (hereinafter , Simply referred to as a brake pedal switch), 59 is a brake depression sensor, 60 is a gear select lever, 61 is a slope start assist device (hereinafter abbreviated as HSA) switch, 62 is an idle control switch, 63 is an indicator, 65 Is a door switch, 66 is a key switch, 67 is brake air piping, and 68 is a block switch. Kieatanku, the brake air pressure sensor 69, 70 is an electromagnetic proportional pressure control valve, the air pressure switch 71 and 73, 72 HSA valve, 7
Reference numeral 4 is an air master, and 64 is a control unit (hereinafter abbreviated as C / U) as a control means for controlling the pump / motor 14 and the actuator based on the outputs of the above-mentioned sensors and switches to regenerate the brake energy.
The C / U 64 includes a memory (not shown) for storing the programs, maps and flags described below.

FIG. 3 is a flow chart of a program stored and executed in the C / U 64 shown in FIG. 1, and the operation of the embodiment shown in FIG. 1 will be described based on this flow chart.

When the program starts, the C / U 64 executes an initialization subroutine, turns off all outputs, and checks the built-in RAM (not shown) for clearing (step S1 in FIG. 3).

After performing initialization, switch 33, 45, 46, 50,
52, 53, 55, 58, 61, 62, 65, 66, 71 and 73 and a read subroutine for signals from the sensor 38 are executed (step S2), and then rotation signals read from the sensors 35, 36 and 40 The (pulse) processing subroutine is executed to calculate the engine speed, the input shaft speed, and the vehicle speed, respectively (step S3). In these processes, a flag FL-SPEED of FIG. 15 described later is generated according to the vehicle speed.

Then, the processing subroutine of the analog signals read from the sensors 2, 34, 37, 39, 41, 47, 56, 59, 69 is executed, and the engine load, the clutch stroke, the shift stroke, the oil temperature, the pressure of the digital value, respectively, are executed. Obtain the accelerator opening, the amount of brake depression, and the brake air pressure (step S4).

The reading and processing of these signals are updated every C / U processing. In addition, a flag (described later) used in the logic according to the read signal and the processed signal is set in these subroutines (excluding the flag set / reset in the control history).

Subsequently, it is checked whether or not the key switch 66 is on (step S5 in the same step), and when it is off, the all control stop subroutine is executed (step S6).

This subroutine is a key switch when the vehicle is stopped or running.
In order to ensure safety even if 66 is turned off, after returning all hydraulic systems to a safe state, in step S7 the actuator relay (not shown) is turned off and the C / U64 power is turned off to perform all control. It is to stop.

When the key switch 66 is turned on in step S5, the RBS
It is checked whether the main switch 53 is on (step S8 in FIG. 3), and when it is off, a normal brake control mode subroutine described later is executed (step S22), but when it is on, the driver Assuming that you are going to perform a brake energy regeneration device (hereinafter, RBS) operation,
Continue control.

Therefore, the C / U 64 checks whether or not the driver operates the parking brake 51 (at step S9),
When not in operation (parking brake switch 52a
(When P / B1 is off), RBS can be used and step S
Although the process proceeds to step 11, when it is operated (when the parking brake switch 52a is on), the process proceeds to the normal brake control mode (step S22 of the same step) to prohibit the use of the RBS. 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, in order to transmit the output torque of the pump / motor 14 to the wheels 11 while the parking brake is being operated, such as when starting on a slope, it is checked whether or not another parking brake switch 52b is on (step S10).

Here, the parking brake switch 52b (P / B2) is
As shown in FIG. 14, it is turned on only when the knob 51a of the parking brake lever 51 is pushed. That is, since the state in which the knob 51a is pressed is when there is an 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 turned on. Is.

Next, the C / U 64 checks the selected gear by the gear position detection sensor 38 and the gear shift stroke sensor 39 (step S11), and if the gear is N (neutral) or R (reverse), RBS. The routine proceeds to the normal brake control mode subroutine (step S22) without using, but if the gear is 1st to 5th, RBS can be used and control is continued.

Then, it is checked from the output of the vehicle speed sensor 40 whether or not the vehicle is stopped (at step S12), and if the vehicle is traveling, the process proceeds to step S14 and whether the current speed is equal to or lower than the allowable rotation speed of the pump / motor 14 or not. Check whether or not. This permissible rotation speed is determined by the pump / motor 14 electromagnetic clutch 13, PTO shaft 1
2. Since it is connected to the wheels 11 via the PTO device 8, the propeller shaft 9 and the axle 10, if the gear ratio of the PTO device 8 and the axle 10 is constant, it can be judged by the vehicle speed, and the pump / motor which is a commercial product From the allowable speed of 14 to the gear ratio,
Multiplying the wheel circumference, for example, RBS up to 50 km / h
Can be conditioned to be within the usable range of.

In step S14, if the vehicle speed is 50 km / h or less, that is, if the speed of the pump / motor 14 is within the permissible speed range, the control continues, but if it is determined that the speed exceeds the permissible speed range, the normal brake control of step S22 is performed. Execute a mode subroutine. When this subroutine (step S22) is executed, "1" is set in the bit 2 of the flag FL-RBS in FIG.

If the vehicle is a bus when the vehicle is stopped in step S12, a start prohibition subroutine is executed (step S13). This subroutine prohibits the use of the hydraulic circuit when the bus is open, and when the door is open, it is considered that the passenger is getting on and off, and care is taken to ensure passenger safety. This is executed in order to prevent the vehicle from moving even when the accelerator is stepped on.

Next, the C / U 64 checks the driver's pedal operation in the order of the brake (at step S15) and the accelerator (at step S16) (each signal processing is completed by the analog signal processing subroutine at step S4). The reason why the check of the brake operation is prioritized over the check of the accelerator operation is that the brake is prioritized as a safety side of the vehicle when the brake pedal 57 and the accelerator pedal 54 are stepped on at the same time.

If the brake pedal 57 is depressed in step S15,
The energy recovery mode subroutine shown in FIG. 4 is executed (step S17).

First, bit 0 (BRK1) of flag FL_REDAL shown in FIG.
Is checked (step S171 in FIG. 4). This flag
BRK1 is a flag that is set when the energy recovery is executed for the first time as shown in FIG. 17, and is reset at the beginning of the normal brake control and the energy regeneration control. Therefore, when the brake is used for the first time, it is 0, so the vehicle speed is checked from the speed flag (FL_SPEED, see FIG. 15) (step S172).

When the vehicle speed is in the low speed range (for example, vehicle speed is 10km / h or less), less energy can be collected, but when the brakes are often used at low speeds such as in traffic jams, the hydraulic system control is frequently used accordingly, so hydraulic pressure is used. Speed flag FL-SP
If any one of bit 0, bit 1, and bit 2 of EED is "1", the normal brake control mode subroutine is executed (step S173). This subroutine is the same as the subroutine of step S22 of the main program.

When the vehicle speed exceeds, for example, 10 km / h (bit 0, bit 1, and bit 2 are all "0"), a control torque search is performed using the brake torque map shown in Fig. 9 (step S174), and the brake is applied. The braking torque that the driver is going to generate is retrieved and stored from the depression amount (angle) of the pedal 57.

Explaining the brake torque map shown in FIG. 9 here, this map shows a brake pedal 57 such as an air brake or an air over hydraulic (air / oil) brake.
It is based on a diagram showing the relationship between the amount of pedaling and the total braking torque per vehicle (front and rear wheels). From the pedal operation feeling, passenger feeling and safety, pedal operation with RBS is possible. The actual effectiveness of the brake is equivalent to the operation of the air brake, air / oil brake, etc.

In FIG. 9, the initial state of depression of the brake pedal 57 (for example, 0 to 3.5 °) is used as brake play, and the output voltage of the brake depression amount sensor 59 attached to the brake pedal 57 is set to 0 by the brake pedal switch 58. When the brake pedal 57 exceeds the initial state (for example, 3.5 °), the switch 58 is turned on and the sensor 59 outputs a voltage proportional to the pedal depression angle. Therefore, the depression angle of the brake pedal 57 can be detected from the output of the sensor 59.

The section following the initial stepping on of the brake pedal 57 is a braking force control section (for example, 3.5 ° to 16 °), and the pump / motor 14, the air brake, or the air / oil brake is controlled in this section. Therefore, the braking torque T corresponding to the depression angle of the brake pedal 57 is obtained from the map.

Section that exceeds the braking force control section (for example, 16 ° to 25
) Is during panic braking, and at this time, the electromagnetic proportional air pressure control valve 70 is forcibly pushed down by a link mechanism (not shown) communicating with the brake pedal 57, and the brake air tank 68 and the braking force generation device. , For example, air
The maximum braking force by compressed air is generated by making all of the oil type air master 74 and. At this time, use of the hydraulic circuit is prohibited because the vehicle may become unstable.

The control proceeds to step S174 when the brake is first depressed (flag BRK1 = 0) and the vehicle speed is low speed (for example, 10 Km / h) or more in step S172, or the brake is continuously depressed. When (flag BRK1 = 1) and step S1
This is the case where the vehicle speed detected at 75 is a very low speed (for example, 2 km / h) or more.

In the low speed range (step S172), where the vehicle speed is 10 km / h or less in the initial state, the energy that can be recovered is small for the control and drive of the hydraulic circuit, but once the pump / motor 14
After braking with hydraulic pressure by (flag BRK1 =
1), fine speed at which the pump / motor 14 rotates stably (2k
This is because it is used continuously until m / h) to recover as much deceleration energy as possible.

When it is detected in step S175 that the vehicle speed has become a very low speed (2 km / h or less), the normal brake control mode subroutine is executed (step S176), and braking is performed by the air brake or the air / oil brake. Similar to step S173, this subroutine is the same as the subroutine of step S22 of the main program.

After executing the energy recovery mode subroutine in this way, the C / U 64 executes the engine brake mode subroutine shown in FIG. 5 (step S1 in FIG. 3).
8). This subroutine is for eliminating the difference in feeling from a normal vehicle, that is, for generating a braking force equivalent to an exhaust (exhaust) brake or an engine brake.

The exhaust brake is an auxiliary brake that is operated by the hand lever 48 (or switch) in the driver's seat without depressing the brake pedal 57, and the engine brake generates braking force as its load when the vehicle drives the engine. It is an auxiliary brake that makes it.

In this braking energy regeneration device, in order to recover as much kinetic energy as the vehicle has in the energy recovery mode, the engine clutch is disengaged (see FIG. 8) and the wheel 11 and the engine 1 are separated from each other.
Performs alternative control of two auxiliary brakes. Therefore, the above engine brake mode subroutine is executed, and the braking force generated by the two auxiliary brakes is generated by the pump / motor 14 instead.

In step S181 of FIG. 5, bit 0 of the flag FL_PEDAL
Based on (BRK1), as in step S171 in FIG. 4, it is checked whether the braking by hydraulic pressure is at the beginning or is continuing.
Since the flags in step S181 and step S171 are common, if the brake control by hydraulic pressure is started in either step S17 or step S18, step S175 or step S18 is performed in both modes of step S17 and step S18.
Proceed to step 3 to continue the brake control.

In step S182, similarly to step S172, the brake control by hydraulic pressure is not started in the low speed range (for example, vehicle speed 10 km / h) or less (one of bit 0 to bit 2 of flag FL_SPEED is 1). On the other hand, in step S183, step S175
Similar to the above, once the brake control by the pump / motor 14 is started (flag BRK1 = 1), the vehicle speed is very low (for example, 2k).
Until it falls to m / h) (bit 0 or bit 1 of flag FL_SPEED is 0), brake control by hydraulic pressure is continued.

Next, it is checked whether or not the hand lever 48 (which may be a switch) in the driver's seat is on (step S184 in FIG. 5), and if it is on, a braking torque equivalent to the exhaust brake is retrieved from the map (same step). S185).

FIG. 10 is a braking torque map equivalent to the exhaust brake, and since this map has the same line diagram as the actual exhaust brake, it does not give a feeling of discomfort to a driver who is accustomed to the exhaust brake. Also, since this map is the braking torque generated by the engine,
In order to generate the braking torque at the wheel 11, the braking torque value of the net obtained by multiplying the gear stage currently being shifted by the final gear ratio is stored.

In step S184, when the hand lever 75 is off, a braking torque equivalent to actual engine braking is searched from the map shown in FIG. 11 (step S186).

FIG. 11 is a braking torque map corresponding to engine braking. Since this map also shows the braking torque generated by the engine 1, in order to generate the braking torque at the wheels 11, the gear position currently being shifted and the final gear position are set. It is converted into a net value multiplied by the gear ratio and stored.

If the brake pedal 57 is stepped on to the subroutine of step S18, from the subroutine of step S17,
When the accelerator pedal 54 is not depressed (when the accelerator pedal is in the idle position), the process proceeds from step S16, but the engine brake mode subroutine (step S18 in FIG. 3) is for the auxiliary brake generated by the engine. Since it is the substitute mode, step S17 in FIG.
It has nothing to do with the operation of the brake pedal. In other words, both the exhaust brake and the engine brake, the accelerator pedal 54
Unless stepped on, an alternative force is generated under the control of the output of the hand lever 48. In other words, step S174
When the braking force corresponding to the amount of depression of the brake pedal is obtained, the braking torque equivalent to the exhaust brake or the engine brake is further obtained if the vehicle is traveling at a constant speed or higher.

Subsequently, the C / U 64 determines the capacity of the pump / motor 14 required to generate the required control torque retrieved and stored in the subroutines of the steps S17 and S18 according to the pressure in the hydraulic circuit. The subroutine is executed (step S19 in FIG. 3).

First, it is checked whether or not the normal brake control mode subroutine is executed by the bit 2 of the flag FL_RBS shown in FIG. 16 (step S191 in FIG. 6), and if the normal brake control mode subroutine is executed, the pump Since the control of the motor 14 is unnecessary, all the subroutines in step S19 are passed.

Next, if the hydraulic brake control using the pump / motor 14 is performed in steps S17 and S18 described above, the required braking torque of each brake mode retrieved in steps S17 and S18 is integrated (step S192). That is, the total braking torque required to be generated by the pump / motor 14 is calculated.

Subsequently, the pump / motor 14 obtained by dividing the required torque value obtained in step S192 by the final gear and the gear ratio of the PTO device is used.
From the torque value T at
Find the capacity V _{P of the} motor 14.

V _P = 200πT / P (1) where P: Pressure in hydraulic circuit detected by pressure sensor 47 (kg / c
m ² ), V _P : Capacity of pump / motor 14 (cc), T: Required control torque (kg · m).

However, since it is complicated to calculate this, a map of pressure, torque and capacity as shown in FIG. 12 is created in advance by this equation (1), and the necessary capacity is searched from this map. Yes (at step S193).

In the present invention, as shown in FIG. 2, an oblique shaft type axial piston type (or a swash plate type axial piston type may be used).
Since the pump / motor 14 can be used, its capacity
V _P is controlled by controlling the tilt angle of the swash shaft (or swash plate).

Then, it is checked whether or not the capacity V _P of the pump / motor 14 retrieved from the above map exceeds the maximum capacity V _MAX of the pump / motor 14 (step S194 in the same step), and if it exceeds, V _P = V _MAX (Step S195). And the flag
BRK2, which is bit 1 of FL_PEDAL (see FIG. 17) is checked (at step S196), and when the driver does not step on the brake pedal 57 (BRK2 = 0), the braking torque generated by the pump / motor 14 is Even if the torque is less than the required torque, control continues as it is.

When the driver depresses the brake pedal 57, the flag BR
Since K2 = 1, in order to supplement the insufficient braking torque with the air brake or the air / oil brake, step S197
Proceed to and search for the insufficient braking torque from the map shown in FIG.

Here, the method for searching the insufficient braking torque on this map
Explaining in the figure, when the point of the hydraulic circuit pressure P corresponding to the required control torque T is on the straight line or below the maximum displacement Vmax of the pump / motor 14, that is, in the shaded portion of the figure, V _P ≦
Since it is V _MAX , the required braking torque can be generated only by the pump / motor 14 (for example, required braking torque T _F ), but when it is above the line of V _MAX (for example, required braking torque T _A ), V _P
> V _MAX , and pump / motor 14 requires braking torque T _A
Will not be able to occur.

Therefore, in the case of V _P > V _MAX , the insufficient braking torque, for example, T _A −T _P is searched and obtained, and this amount is supplemented by the air brake or the air / oil brake.

Therefore, the electromagnetic proportional air pressure control valve 70 is driven so as to send the air matching the insufficient braking torque generation retrieved in step S197 from the air tank 68 to the air mucker 74 (step S198).

When V _P ≦ V _MAX in step S194 and when flag BRK2 = 0 in step S196, the electromagnetic proportional air pressure control valve
The brake is operated only by the pump force without activating 70 (step S200).

After executing the above subroutine, the C / U 64 resets the flag BRK2 to 0 (step S199 in the same step) and returns to the main program.

Returning to step S16 of the main program, when the accelerator pedal 54 is stepped on, the C / U 64 causes the energy regeneration mode subroutine (which uses the deceleration energy stored in the high pressure accumulator 26 to travel).
Is executed (Schip S20 in FIG. 3).

In this subroutine, the required amount of torque is obtained by detecting the depression amount of the accelerator pedal 54 for each gear, and the tilt angle (capacity) of the pump / motor 14 is determined by this torque and the current accumulated pressure in the hydraulic circuit.

Then, the main program executes the normal brake control mode subroutine of step S22, which is a mode in which the brake is applied only by the air brake or the air / oil brake without using the hydraulic pressure.

Explaining this subroutine based on FIG. 7, first,
Depression amount of brake pedal 57 and electromagnetic proportional air pressure control valve 70
The discharge pressure of is retrieved from the map in FIG. 9 (step S221 in FIG. 7). This is a search that is performed because the braking torque is determined by the discharge pressure sent to the air master 74 in the case of, for example, an air-oil brake, and this map is used to match the feeling of braking with a normal air-brake vehicle (or,
It has a discharge pressure diagram equivalent to that of an air / oil brake vehicle. Incidentally, the braking torque is obtained by giving the depression amount of the brake pedal 57 even when the routine proceeds to the subroutine from steps S8, S10, S11 and S14 in FIG.

Next, the electromagnetic proportional air pressure control valve 70 is driven based on the discharge pressure retrieved in step S221 (step S222), and since this subroutine uses only air, the pump / motor 14 is turned off to turn off the hydraulic system. Set the tilt angle to "0" (same step
S223), the circuit switching valve 25 and the electromagnetic clutch 13 are turned off (step S224), and the process returns to the main program.

After the above control, the C / U 64 performs oil amount control (3rd
Step S21 in the figure). This oil amount control is a subroutine that determines whether or not oil supply is necessary depending on whether the oil amount detection limit switch 45 is on or off and issues an operation request to the solenoid valves 31 and 32.

Further, the C / U64 is a vehicle speed signal from the vehicle speed sensor 40, an accelerator opening detection sensor as in the well-known Japanese Patent Laid-Open No. 60-11769.
Based on the map shown in FIG. 18, which was created by reading the signal corresponding to the depression amount of the accelerator pedal 54 from 56 and the select signal (matrix signal) from the gear select lever 60 according to the vehicle speed and the depression amount of the accelerator pedal 54 Proper
Select T / M5 gear (steps S23 and S2 in Fig. 3)
Four).

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

Note that the C / U 64 has bit 3 of the flag FL_RBS set to 1 when traveling only by hydraulic pressure based on the clutch control method determination subroutine shown in FIG. 8 (step S241 in FIG. 8). The engine clutch has been disengaged since (step S242). Bit 3 of this flag FL_RBS is the first
As shown in Fig. 16, it is always set in the energy recovery mode, and in the energy regeneration mode, it is set and set in a place where only hydraulic pressure is used for traveling.

Regarding the clutch on / off control of the engine clutch, an automatic clutch type automatic transmission vehicle is already known at present.
Further, even if the vehicle does not have an automatic transmission, it suffices if only the engine clutch can be automatically connected / disconnected. Further, in the case of a fluid automatic transmission vehicle, the same effect can be obtained by disconnecting the engine from the engine by controlling the gear to the neutral position.

Continuously, the pump / motor determined by the above-mentioned energy recovery mode, regeneration mode, normal brake control mode, etc.
A hydraulic circuit control subroutine for actually driving these is executed according to the capacity of 14, the engagement / disconnection of the electromagnetic clutch 13, and the switching position of the circuit switching valve 25 (step S25 in FIG. 3).

This hydraulic circuit control subroutine is for actually controlling the circuit switching valve 25, the pump / motor 14, and the electromagnetic clutch 13 which form the hydraulic circuit based on the above-described various determination / calculation results.

After performing the hydraulic circuit control (step S25), the signals from the direct-coupling cooling relay switch 33 and the water temperature sensor 34 are read to stabilize the idle rotation during the warm-up operation of the engine 1 and during cooling, and the replenishment pump 30 An idle control subroutine for stabilizing idle rotation when driving is executed (step S26).

After that, the target position of the step motor 3 is set by the output torque of the engine 1 determined in the above-mentioned energy regeneration mode or the like, and the engine control subroutine for driving this is executed (step S27). In this case, when the capacity V of the pump / motor 14 determined by the above-mentioned energy regeneration mode is V <250cc, idling is performed, and V> 250cc
At this time, the engine is controlled so that the required engine output obtained from the following equation (2) is generated.

Engine required output = [(T / M required output)-(Pump motor maximum output) x (PTO gear ratio)] / (T / M gear ratio) (2) This engine output is the accelerator pedal depression amount as described above. It is obtained by driving the fuel injection governor by the step motor after converting into.

After the above control and processing, an indicator control subroutine that includes display of hydraulic pressure and power source (hydraulic pressure, engine) and controls display of the indicators 63 is executed (at step S2).
8).

Then, on condition that the vehicle speed is 0 and the brake pedal 57 is stepped on, the HSA valve 72 is closed to keep the brake state, and the accelerator pedal 54 is stepped on or the gear select lever 60 is set to the neutral position. As a result, the HSA control subroutine for releasing the brake state is executed (at step S29).

After this, it is checked whether or not it is time to execute self-diagnosis (step S30 in the same step), and when it is time, it is periodically (for example, 5
00ms) self-diagnosis is performed (step S31 of the same step), and after waiting for a time to keep the processing time constant (step S3 of the same step).
2) and returns to step S2 to repeat the above processing.

It should be noted that the above-mentioned subroutine (steps S23 to S31) can use a technique that is already known at present.

〔The invention's effect〕

As described above, according to the present invention, as shown in the flowchart of FIG. 6 and the map of FIG. 13, when the required brake torque cannot be obtained even if the pump displacement is maximized,
By maximizing the pump capacity and controlling the electromagnetic proportional air pressure control valve to compensate for the shortage brake torque, it was achieved by the air brake device, so that it was achieved that the vehicle could not reach the predetermined position due to insufficient hydraulic brake. It is possible to avoid a dangerous situation such as not stopping at, and realize safe vehicle operation.

[Brief description of drawings]

FIG. 1 (a) is a conceptual diagram of a vehicle brake energy regeneration device according to the present invention, and FIG. 1 (b) is a diagram showing a configuration of an embodiment of a vehicle brake energy regeneration device according to the present invention. 2 (a) and 2 (b) are a sectional view and a perspective view, respectively, of the oblique shaft type axial piston pump / motor used in the present invention, and FIG. 3 is a program stored and executed in the control means of the present invention. FIG. 4, FIG. 4 is a flowchart of the energy recovery mode subroutine, FIG. 5 is a flowchart of the engine brake mode subroutine, FIG. 6 is a flowchart of the pump calculation subroutine, and FIG. 7 is normal brake control. FIG. 8 is a flowchart of a mode subroutine, FIG. 8 is a flowchart of a clutch control method determination subroutine, and FIG. Torque map diagram, Fig. 10 is a braking torque map diagram equivalent to the exhaust brake, Fig. 11 is a braking torque map diagram equivalent to the engine brake, Fig. 12 is a braking torque map diagram of the pump / motor, and Fig. 13 is a pump. -Explanation diagram of the braking torque map of the motor, FIG. 14 is a schematic diagram illustrating the parking brake lever, FIG. 15 is a diagram illustrating the flag FL_SPEED, FIG. 16 is a diagram illustrating the flag FL_RBS, and FIG. FIG. 18 is a diagram for explaining the flag FL_PEDAL, and FIG. 18 is a gear shift map diagram based on the vehicle speed and the accelerator pedal depression amount. In the figure, 1 is an engine, 5 is T / M, 8 is a PTO device, 13
Is an electromagnetic clutch, 14 is a pump / motor, 25 is a circuit shutoff (switching) valve, 26 is a high pressure accumulator, 27 is a low pressure accumulator, 47 is a pressure sensor, 57 is a brake pedal, 58 is a brake pedal (return position) switch, 59 Is a brake depression amount sensor, 64 is a C / U as a control means, 67 is a brake air pipe, and 70 is an electromagnetic proportional pressure control valve. In the drawings, the same reference numerals indicate the same or corresponding parts.

Claims (1)

[Claims] 1. When the deceleration energy is recovered, the low pressure accumulator is hydraulically accumulated in the high pressure accumulator through a pump / motor and a circuit valve connected to the power branch mechanism, and when the accumulated energy is regenerated, the high pressure accumulator is used to regenerate the circuit valve. And a hydraulic circuit for releasing hydraulic pressure to the low pressure accumulator via the pump / motor, a brake pedal switch, an air pressure control valve, and an air brake device,
When the pump displacement of the pump / motor of the hydraulic circuit obtained from the memory map in accordance with the total required braking torque exceeds the maximum displacement, the pump displacement is maximized to operate the hydraulic circuit and the switch is turned on. A braking energy regeneration device for a vehicle, comprising: a control means for supplementing the insufficient braking torque with the air brake device by controlling the control valve when the braking energy is operating.