JPH0613259B2 - Engine overrun prevention control device for speed change steering device - Google Patents

Description

TECHNICAL FIELD The present invention relates to an engine overrun prevention control device for a gear shift steering device.

[Conventional technology]

In a vehicle transmission having a hydrostatic-mechanical continuously variable transmission or a speed change steering for a tracked vehicle, engine speed control is performed only by speed ratio control, and engine overrun prevention is also allowed for overrun maximum rotation. The actual speed of the engine is compared with the speed, and only the speed ratio control is performed so that the latter converges to the former.

[Problems to be Solved by the Invention]

However, it was difficult to reduce the engine speed when the speed ratio was the maximum mechanically and the engine was at the allowable overrun maximum speed or higher.

[Means for solving problems]

In view of the above points, an object of the present invention is to provide a control device capable of surely preventing engine overrun in a vehicle having a hydrostatic-mechanical continuously variable transmission mechanism. In a gearshift steering system for a tracked vehicle having a hydrostatic-mechanical continuously variable transmission, a gearshift operating in a direction in which the speed ratio increases when the actual engine speed is higher than the maximum engine overrun allowable speed. When the speed ratio is higher than a predetermined maximum speed ratio and the engine speed is higher than the allowable engine overrun maximum speed, which is provided between the pump discharge rate control actuator, the fuel injection quantity setting device and the fuel injection quantity control actuator. Is provided with a fuel injection amount limiter for limiting the fuel injection amount.

[Action]

In this case, in addition to the speed ratio control, when the speed ratio reaches the maximum value on the mechanism and the actual engine speed is higher than the maximum overrun allowable speed, the fuel injection amount limiter is activated By reducing the injection amount, it is possible to reduce the actual engine speed to the maximum overrun allowable speed.

〔Example〕

Embodiments according to the present invention will be described below with reference to the drawings.

FIG. 1 is an explanatory view showing an apparatus of one embodiment according to the present invention.

In the figure, 1 is one input shaft 9 connected to the engine 4.
And a two-sided left and right output shafts 10 and 11, and is composed of a speed change unit 2 and a steering unit 3.

The speed change unit 2 has a speed change hydraulic pump 5 driven by an engine and a speed change hydraulic motor 6 driven by the discharge oil of the hydraulic pump. The output shaft of the hydraulic motor is the planetary gear train of the speed change unit 2. The mechanically transmitted power from the engine 4 and the power from the hydraulic motor are combined with each other. In addition, the transmission unit 2 has a plurality of planetary gear trains and a plurality of hydraulically actuated clutches, and by selectively engaging one of the clutches, the transmission unit can be selected from four speed stages from the first speed to the fourth speed. You can do it. Also forward,
There are two sets of bevel gears and two hydraulically operated clutches for reverse switching. Here, the shifting hydraulic pump 5 is a variable displacement pump, and the rotation speed of the shifting hydraulic motor 6 can be controlled by controlling the discharge amount thereof. By controlling the number of revolutions of the hydraulic motor 6, the speed change unit 2 can change the speed continuously in each speed stage.

The steering unit 3 has a steering hydraulic pump 7 driven by an engine and a steering hydraulic motor 8 driven by the oil discharged from the hydraulic pump. The output shaft of the hydraulic motor 8 is a gear shift operation. It is connected to the planetary gears on the left and right output shafts of the steering device so as to rotate left and right in reverse, and is combined with the power from the output shaft of the transmission. Here, the steering hydraulic pump 7 is a variable displacement pump, and the rotation speed of the steering hydraulic motor 8 can be controlled by controlling the discharge amount thereof. When the rotational speed of the hydraulic motor 8 is zero, the rotational speeds of the left and right output shafts become the same rotational speed, and the vehicle goes straight. When the rotational speed of the hydraulic motor is forward or reverse, depending on the rotational speed. There is a difference in the number of rotations of the left and right output shafts, and the vehicle can turn right or left.

Reference numeral 12 is a shift pump discharge amount control actuator for controlling the discharge amount of the shift hydraulic pump 5, and 13 is a steering pump discharge amount control actuator for controlling the discharge amount of the steering hydraulic pump 7. The discharge amount is controlled by the control signals k and l from the control device 31, respectively. Further, 14 is a fuel injection amount control actuator for controlling the fuel injection amount of the engine, and the fuel injection amount is controlled by a signal m from the control device 31.

Reference numeral 21 is an engine speed detector that extracts the engine speed signal N _{E according} to the engine speed, and 22 is a speed change hydraulic motor speed detection that extracts the speed change hydraulic motor speed signal N _{M based} on the speed of the speed change hydraulic motor 6. A reference numeral 23 is a gear shifter output rotation speed signal N _O for the gear shifter output rotation speed, and a gear shifter output rotation speed signal N _N is a rotation pressure motor rotation speed signal N _N for the steering hydraulic motor rotation speed. It is a steering hydraulic motor rotation speed detector. 25 is an accelerator pedal position detector for extracting this signal a according to the accelerator pedal position for controlling the engine speed, and 26 is a change lever for detecting four positions of forward, reverse, neutral, and super turning. ，
A position selection switch 27 for detecting a signal b corresponding thereto detects a brake pedal position, a brake pedal position detector 27 for extracting the signal c, 28 detects a steering wheel turning angle for turning the vehicle. , A steering wheel angle detector for extracting the signal d.

Reference numerals 15, 16, 17, and 18 denote first speed clutches that are operated by control signals e, f, g, and h from the control device 31 to engage the hydraulically operated clutches for selecting each speed stage of the transmission unit. Solenoid valves for actuation, solenoid valves for actuating second speed clutch, solenoid valves for actuating third speed clutch, solenoid valves for actuating fourth speed clutch, 19 and 20 engaging the hydraulic actuating clutch for switching between forward and reverse. Therefore, the forward clutch actuating solenoid valve and the reverse clutch actuating solenoid valve are operated by the control signals i, j from the control device 31.

31 is a control device, which is used for the signals a to d and
When N _E , N _M , N _N , and N _O are input, the control signals k and l and the fuel injection amount control of the engine are supplied to the two hydraulic pumps 5 and 7 for shifting and steering according to the input signals. A control signal m is sent to the actuator 14, and each clutch actuating solenoid valve 1
5, 16, 17, 18, 19, 20 control signals e, f,
It outputs g, h, i, j.

The operation of the above configuration will be described.

The gearshift steering apparatus according to the present invention uses a hydrostatic-mechanical continuously variable transmission mechanism in the gearshift section, and controls the rotational speed of the gearshift hydraulic motor 6 by controlling the discharge amount of the gearshift hydraulic pump 5. Thereby Is changing. By changing this speed ratio arbitrarily and continuously, the load torque applied to the engine is continuously changed, and the engine speed is controlled to an optimum engine speed for a certain fuel injection amount. Is always operated in a desired optimum state.

However, there is a risk that the engine will overrun if the fuel injection amount is set to the maximum when the accelerator pedal is fully depressed, or if full engine braking is applied. If overrun,
In order to quickly reduce the rotation speed, (1) increase the speed ratio x, increase the engine load torque, reduce the engine rotation speed, and (2) reduce the fuel injection amount to an appropriate value. Will be required.

FIG. 2 shows a block diagram forming a main part of one embodiment according to the present invention, and an apparatus for embodying the operations of (1) and (2) above will be sequentially described.

Operation of (1) When the accelerator pedal position signal a from the accelerator pedal position detector 25 is input to the fuel injection amount setting device 32, the fuel injection amount setting device 32 stores the fuel injection amount for the accelerator pedal position in advance. The fuel injection amount signal m
Is input to the fuel injection amount limiter 33. At the same time, the fuel injection amount signal m is also input to the engine speed setting device 34. The engine speed setter 34 stores in advance the engine optimum operating speed for the fuel injection amount so that the engine can be operated in an optimum state, and the optimum speed signal n _e is output for the input signal m. . From the optimum rotation speed signal and the engine rotation speed signal N _E output from the engine rotation speed detector 21, a speed deviation detector 35 extracts an engine rotation speed deviation signal Δn _e = | n _e −N _E |.
The engine speed deviation signal Δn _e is input to the polarity adding circuit 36. On the other hand, the position selection switch 26
Is input to the speed stage logic circuit 37, the speed stage of the speed change unit is selected according to the state of the position selection switch 26, and the control signals e to j are output to the hydraulic clutch actuating solenoid valves 15 to 20, respectively. To be done. The control signals e to h corresponding to the speed stages are also input to the polarity adding circuit 36. The polarities shown in FIG. 3 are added to the absolute value of the engine speed deviation signal Δn _e depending on the states of the above signals.

Here, this polarity is such that in each speed stage, when N _E > n _e , the speed ratio x increases and the engine load torque increases, and when N _E <n _e , the speed ratio x decreases. Then, the load torque of the engine is added in the direction of decreasing. The engine speed deviation signal Δn _e to which the polarity is added by the polarity adding circuit 36 is integrated by the next integrator 38. The output of the integrator 38 becomes the shift pump discharge amount control signal k and is sent to the shift pump discharge amount control actuator 12. Assuming that the upper limit of the optimum operating speed signal n _e is the signal n _emax corresponding to the engine overrun allowable maximum speed, the signal input to the integrator 38 is (a) the engine speed signal as described above. When N _E > n _emax , the input is made so that the load torque increases, so that the shift pump discharge amount control signal also changes in the direction of increasing the load torque to increase the load torque, and the engine speed n _Acts to reduce to _emax .

Action (2) By action (a) above, the actual engine speed can be controlled at a certain optimum operating speed without exceeding the maximum engine overrun allowable speed. However, the overrun prevention control by the engine load torque control described above can be applied only when the speed ratio x has not reached the predetermined maximum value x _max . That is, with the speed ratio x = x _max ,
When the actual engine speed exceeds the maximum overrun allowable speed, it is mechanically impossible to further increase the speed ratio x. Therefore, the speed ratio control (load torque control) according to (a) above Is no longer applicable. Therefore, when the speed ratio x reaches x _max, and became N _E> n _emax is
It is necessary to control the amount of fuel injection. That is, the engine speed signal N _E and the speed changer output shaft speed signal N _O output from the speed changer output speed detector 23 are input to the speed ratio calculation circuit 39 and the speed ratio signal x = N _O / N _E Calculated and output. The speed ratio signal x is input to the speed ratio comparator 40 and is input to the maximum speed ratio signal.
If it is compared with x _max and is larger than x _max , the overspeed ratio signal p is output. At the same time, the engine speed signal N _E is input to the engine speed comparator 41 and compared with the overrun allowable maximum speed signal n _{emax. If} it is larger than n _emax , the overrun signal q is output.

The logical operation of the two output signals p and q is performed in the logical product circuit 42, and the fuel injection amount control signal r is output only when all the signals are generated. The fuel injection amount limit signal r is input to the fuel injection amount limiter 33. The fuel injection amount limiter 33 outputs a fuel injection amount signal m, which is another input, by a multiplier 1 when the limit signal r is not input, and outputs it when the limit signal r is input. It has a logical operation function of multiplying the quantity signal m by a multiplier α (0 ≦ α <1) and outputting a new fuel injection quantity signal m that narrows down the fuel injection quantity. The output fuel injection amount signal m is input to the fuel injection amount control actuator 14.

By carrying out the above-mentioned actions (1) and (2) in sequence, the engine is prevented from overrunning, and even if it overruns, the fuel injection amount is throttled, so overrun is avoided in a very short time. It

〔The invention's effect〕

 In the above case, there are the following effects.

The load torque of the engine is changed by increasing or decreasing the speed ratio x, and the engine speed can be controlled by this. Therefore, if the actual engine speed exceeds the allowable overrun speed, the speed ratio x is further increased. The engine speed of can be reduced and converged to the overrun allowable speed.

Further, when the speed ratio x increases and reaches the maximum speed ratio x _max , the fuel injection amount is reduced, so that the engine speed decreases in an extremely short time, and overrun can be avoided. .

The engine overrun prevention control device can be widely applied to prevent engine overrun in the same type of hydrostatic-mechanical continuously variable transmission.

[Brief description of drawings]

FIG. 1 is an explanatory view showing a gear shift steering device according to one embodiment of the present invention, FIG. 2 is a block diagram showing a main part of the present invention, and FIG. 3 shows a polarity added to an engine speed deviation signal. It is an explanatory view shown. DESCRIPTION OF SYMBOLS 1 ... Gearshift steering device, 4 ... Engine, 6 ... Gearshift hydraulic motor, 12 ... Gearshift pump discharge control actuator, 1
4 ... Fuel injection amount control actuator, 32 ... Fuel injection amount setting device, 33 ... Fuel injection amount limiting device.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Takehisa Shio 3,000 Tana, Sagamihara City, Kanagawa Mitsubishi Heavy Industries, Ltd. Sagamihara Works

Claims (1)

[Claims] 1. In a gearshift steering system for a tracked vehicle having a hydrostatic-mechanical continuously variable transmission, the speed ratio increases when the actual engine speed is higher than the engine overrun maximum allowable speed. Is installed between the fuel injection amount setting actuator and the fuel injection amount setting actuator, and the speed ratio is greater than the predetermined maximum speed ratio and the engine speed is the maximum allowable engine overrun speed. An engine overrun prevention control device for a gear shift steering device, which is provided with a fuel injection amount limiter for narrowing the fuel injection amount in the case of a larger value.