JPH0322331B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION Object of the Invention (Field of Industrial Application) The present invention relates to an engine rotation control device when a vehicle is switched between forward and reverse directions.

(Prior art) The engine drives the drive wheels via a continuously variable transmission, and the engine's rotation speed is controlled based on the amount of operation of a travel control device such as a travel pedal, while the continuously variable transmission also drives the drive wheels. In vehicles where the gear ratio is changed based on the operating amount of the operating device, switchback (switching between forward and backward directions) is performed by operating the forward/reverse operating device such as a forward/reverse lever while leaving the operating amount of the traveling device unchanged. Now, the throttle remained the same and only the gear ratio changed.

(Problem to be Solved by the Invention) Therefore, if the forward/reverse operation device is switched with the travel control device fully depressed, the engine will be in a full throttle state, and during deceleration, the engine will not be revved up. Going uphill felt strange, and there were problems with noise, fuel consumption, etc. Another problem was that the braking distance during deceleration becomes long.

Structure of the Invention (Means for Solving the Problems) In order to solve the above-mentioned problems, the present invention has an engine that drives drive wheels via a continuously variable transmission, and the engine controls the amount of operation of a travel control device. On the other hand, the continuously variable transmission changes its gear ratio based on the operating amount of the travel operating device, and also changes its gear ratio from forward to reverse based on the operation of the forward/reverse operating device. In the vehicle, the gear ratio data value outputted based on the operation amount of the travel operation device changes from the forward to reverse value or the reverse value based on the operation of the forward/reverse operation device. a control means for controlling the fluctuation transition of the changing speed ratio data value when the speed change ratio data value changes from the forward speed value to the forward speed value; and a speed change of the continuously variable transmission based on the speed change ratio data value outputted via the control means. a first adjusting means for adjusting a ratio; and a first adjusting means for adjusting a gear ratio, the gear ratio data value being set for deceleration at the time of forward/reverse switching based on the operation of the forward/reverse operating device and the gear ratio data value outputted via the control means. a determining means for determining whether or not the gear ratio data is the gear ratio data; and when the determining means determines that the gear ratio data value is for deceleration, adjusting the engine whose rotation is controlled based on the operation amount of the traveling operation device to an idling state. The gist of the invention is an engine rotation control device when switching forward or backward movement of a vehicle, which comprises a second adjusting means that adjusts the speed of the vehicle.

(Function) When the forward/reverse operation device switches from forward to reverse or from reverse to forward, the gear ratio data value output based on the operation amount of the travel operation device changes from the forward value to the reverse value or from the reverse value. When the value changes to the forward speed value, the control means controls the fluctuation transition of the changing speed ratio data value, and the first adjusting means adjusts the speed ratio of the continuously variable transmission based on the controlled speed ratio data value. adjust.

On the other hand, the determining means is based on the switching operation of the forward/reverse operating device and the speed ratio data value outputted via the control means, and determines whether the speed ratio data value is the speed ratio data for deceleration at the time of forward/reverse switching. Determine. If the determination result is gear ratio data for deceleration, the second adjustment means controls the engine to an idling state.

(Example) Next, a preferred example embodying the present invention will be described below with reference to the drawings.

First Embodiment The first embodiment is an embodiment embodied in a forklift, and FIG. An electric block circuit diagram of a control device that controls the rotation of the engine 2 and controls the gear ratio of the continuously variable transmission 3 is shown. The engine 2 is connected to drive wheels 4 for driving via a continuously variable transmission 3.
drive. Further, the opening degree of the throttle for adjusting the rotational speed of the engine 2 is controlled by a throttle actuator 5 serving as a second adjusting means.

The continuously variable transmission 3 is composed of a variable displacement hydraulic pump 3a and a hydraulic motor 3b.The variable displacement hydraulic pump 3a is driven by the engine 2, and the hydraulic motor 3b is driven by the variable displacement hydraulic pump 3a. It rotates with hydraulic oil supplied by the drive, and transmits its rotational force to the drive wheel 4. Variable displacement hydraulic pump 3a
In this embodiment, a swash plate type hydraulic pump is used, and by changing the inclination angle of the swash plate, the gear ratio is changed, and the hydraulic motor 3b is rotated in forward and reverse directions to move the forklift forward and backward. The inclination angle of the swash plate for adjusting the gear ratio is appropriately controlled by a swash plate actuator 6 serving as a first adjusting means.

On the other hand, the travel pedal 1 is provided with a depression angle detector 7 consisting of a potentiometer for detecting the depression angle thereof, and outputs a travel operation amount signal SG1 having a value proportional to the depression angle, that is, the amount of depression.
Note that the stepping angle detector 7 may be, for example, an inductance type displacement meter or a variable capacitance type displacement meter.

The driving function generator 8 that inputs the driving operation amount signal SG1 is a circuit that converts the input operation amount signal SG1 into engine rotation speed data A for driving, and converts the input operation amount signal SG1 into a function according to preset driving conditions. Based on this, the manipulated variable signal SG1 is converted into rotation speed data A. In this embodiment, the function corresponding to the driving condition is the operation amount (i.e., the driving operation amount signal SG1) so that the engine can be driven optimally under each driving condition such as flat driving, climbing driving, and downhill driving.
A plurality of throttle opening characteristics (i.e., engine rotation speed data A for driving) are set, and the driving function generator 8 selects the optimal one from among the plurality of functions based on the driving conditions at that time. The rotation speed data A for the traveling operation amount signal SG1 is output in accordance with the selected function.

The optimum function of the function generator 8 is selected by a sensor (not shown) that detects the presence and weight of luggage;
Based on the sensor that detects the vehicle speed, the sensor that detects the load during driving, or the selection operation of the selection switch by the driver, the driving conditions and cargo handling conditions at that time are determined, and the optimal function that meets the conditions is determined. Each one can be selected.

The rotational speed data A is output to the throttle actuator 5 via a multiplier 17, which will be described later. The actuator 5 then adjusts the throttle based on the data A and controls the rotational speed of the engine 2 based on the data A.

The traveling operation amount signal SG1 is also output to the swash plate function generator 9. The swash plate function generator 9 is a circuit that converts the input operation amount signal SG1 into speed ratio data E for controlling the tilt angle (speed ratio) of the swash plate of the variable displacement hydraulic pump 3a,
The manipulated variable signal SG1 is converted into gear ratio data E based on a preset function for traveling.

In this embodiment, the function for driving is a manipulated variable (driving manipulated variable signal SG1) so as to obtain the optimum gear ratio for driving under each driving condition such as flat ground driving, climbing driving, and downhill driving. A plurality of swash plate inclination angle characteristics (speed ratio data E) are set for the swash plate function generator 9, and the swash plate function generator 9 selects the optimal one from among the plurality of functions based on the running conditions at that time. , outputs the gear ratio data E for the traveling operation amount signal SG1 to the multiplier 10 in accordance with the selected function.

The optimum function of the function generator 9 is selected by a sensor (not shown) that detects the presence and weight of luggage;
Based on the sensor that detects the vehicle speed, the sensor that detects the load during driving, or the selection operation of the selection switch by the driver, the driving conditions at that time are determined and the optimal function that meets the conditions is selected. It's becoming like that.

The multiplier 10 detects the operation position of a forward/reverse lever 11 as a forward/reverse operation device and changes the speed based on a detection signal from a detector 12 that detects whether the lever 11 is in forward, reverse, or neutral position. The value of the ratio data E is changed to a plus/minus value and output as gear ratio data Ea. Then, in the case of forward movement, the gear ratio data Ea is outputted to the ramp signal generation circuit 13 as it is as a positive value, in the case of reverse movement as a negative value, and in the case of neutrality, the value is invalidated and set to zero. It's summery.

The ramp signal generating circuit 13 as a control means changes the speed ratio data Ea from Ea1 to Ea2 by depressing the travel pedal 1 as shown in FIG.
(Ea1<Ea2), the speed ratio data Ea changes from Ea2 to This circuit sets the degree of fall (speed change ratio) when lowering the gear ratio of the continuously variable transmission 3 from Ea2 to Ea1 when the gear ratio changes to Ea1. As shown in , each of the three variable speeds (rising and falling lines La1 to La3, Ld1 to Ld3)
are prepared and selected in advance by the driver.

Therefore, for example, when the forward/reverse lever 11 is switched from forward to reverse while the amount of depression of the travel pedal 1 is constant, the value of the gear ratio data Ea output from the multiplier 10 immediately changes from positive (Ea1) to negative. (-Ea1), whereas the gear ratio data Ex outputted via this ramp signal generation circuit 13 is Ea1 even at a constant gear ratio as shown in FIG.
It changes from -Ea1. In this case, the gear ratio data Ex in the process of changing from Ea1 to zero is the gear ratio data Ex for decelerating the forward running of the forklift, and the gear ratio data Ex in the process of changing from zero to -Ea1 It can be seen that the data Ex is the gear ratio data Ex for starting the backward running of the forklift and accelerating to increase the gear ratio to a predetermined gear ratio.

Also, when the forward/reverse lever 11 is switched from reverse to forward, similarly to the above, the speed ratio data Ex changes from -Ea1 to zero.
is the speed change data E for decelerating the backward movement of the forklift, and the speed ratio data Ex in the process of changing from zero to Ea1 is the speed change data for accelerating the forklift to start the forward movement and raise it to a predetermined speed ratio. It can be seen that the ratio data is Ex.

The swash plate actuator 6 then uses the gear ratio data output from these ramp signal generation circuits 13.
The swash plate angle of the continuously variable transmission 3 is adjusted based on Ex to control the gear ratio.

Gear ratio data output from the multiplier 10
Ea and the gear ratio data Ex outputted from the ramp signal generation circuit 13 are sent to comparators 14 and 1, respectively.
5 is output. And both comparators 14,
15 are input gear ratio data Ea and Ex, respectively.
If it is positive (Ea, Ex > 0), it outputs a logical value signal of "1", and if it is negative (Ea, Ex≦0), it outputs a logical value signal of "0".
It is output to the EXNOR circuit 16.

Then, the EXNOR circuit 16 connects both comparators 1
4 and 15 are outputting output signals of different logical values, that is, when the gear ratio data Ex is fluctuating due to deceleration as shown in FIG.
A signal SG2 with a logical value of "0" is output. Conversely,
When signals with the same logical value are input, that is, when the gear ratio data Ex is fluctuating due to acceleration as shown in FIG. 3, or when Ea and Ex are equal, the EXNOR circuit 16 inputs the logical value. "1" signal
Output SG2.

Therefore, the comparators 14, 15 and
The EXNOR circuit 16 determines whether the continuously variable transmission 3 is being controlled based on the gear ratio data Ex for deceleration when the forward/reverse lever 11 is switched.

The signal SG2 from the EXNOR circuit 16 is output to a multiplier 17 which inputs the rotation speed data A and outputs the same data A to the throttle actuator 5 at the next stage. The multiplier 17 multiplies this rotational speed data A by the logical value of the signal SG2, and when the signal SG2 has a logical value of "1", the rotational speed data A from the running function generator 8 is directly used as the throttle actuator. Conversely, in the case of a logical value of "0", the value of the rotation speed data A becomes zero, and the rotation speed data A having the value of zero is output to the throttle actuator 5. In this embodiment, the rotational speed data A having a value of zero is a data value for controlling the engine 2 to be in an idling state, and based on this data value, the throttle actuator 5 causes the engine 2 to be in an idling state. The opening degree of the throttle is controlled in this manner.

Next, the effects of the first embodiment configured as described above will be explained.

Now, the forward/reverse lever 11 is running forward at a constant speed with the amount of depression of the travel pedal 1 constant.
When switching from forward to reverse, the gear ratio data output from the swash plate function generator 9 via the multiplier 10
The value of Ea immediately changes from positive to negative.
On the other hand, the gear ratio data Ex outputted from the ramp signal generation circuit 13 changes at a predetermined degree of variation as shown in FIG. Therefore, the gear ratio data Ex
The forklift is decelerated until the value of decreases to zero. Through this change in the gear ratio, smooth deceleration characteristics without impact can be obtained.

Until the value of the gear ratio data Ex decreases to zero, the comparator 14 to which the gear ratio data Ea is input receives a signal with a logical value of "0" and the gear ratio data
The comparator 15 that inputs Ex has a logical value of “1”
The signal is output to the EXNOR circuit 16 at the next stage.

The EXNOR circuit 16 outputs a signal SG2 having a logical value of "0" to the multiplier 17 based on the signals having different logical values.

The multiplier 17 multiplies this logical value of "0" by the rotation speed data A. As a result, the value of the rotational speed data A becomes zero and is output to the throttle actuator 5, which controls the engine 2 to be in an idling state.

Eventually, when the gear ratio data Ex reaches zero, the comparator 15 outputs a signal of "0" to the EXNOR circuit 16. Then, the EXNOR circuit 16 outputs a signal SG2 having a logical value of “1” to the multiplier 17. The multiplier 17 multiplies this logical value of "1" by the rotation speed data A. As a result, rotation speed data A
The value of is output as is to the throttle actuator 5, and the rotation speed of the engine 2 is controlled by the throttle actuator 5 based on the rotation speed data A. Then, as the gear ratio data Ex changes from zero to a negative value, the forklift moves backward and is accelerated until it reaches a predetermined gear ratio Ex. At this time, the gear ratio changes at a predetermined degree of variation, so smooth and optimal acceleration characteristics can be obtained.

Therefore, since the throttle lever of the engine 2 is held in an idling state during deceleration when switching from forward to reverse, it is possible to eliminate the feeling that the engine 2 jumps out due to the lack of acceleration load immediately after the switch, and also to reduce the engine speed during deceleration. You can apply the brakes more effectively. Furthermore, since the engine 2 does not rev up during deceleration, there is no discomfort, there is less noise, and fuel consumption can be kept low.

On the other hand, the same applies when the forward/reverse lever 11 is switched from reverse to forward. That is, when the forward/reverse lever 11 is switched from reverse to forward, the value of the gear ratio data Ea output from the swash plate function generator 9 via the multiplier 10 immediately changes from a negative value to a positive value. On the other hand, the ramp signal generation circuit 13
As shown in FIG. 3, the gear ratio data Ex outputted from the motor changes at a predetermined degree of variation. Therefore,
The forklift is decelerated until the value (absolute value) of the gear ratio data Ex decreases to zero. At this time, it is possible to obtain smooth deceleration characteristics without impact, as described above.

Until the value of the gear ratio data Ex decreases to zero, the comparator 14 to which the gear ratio data Ea is input receives a signal with a logic value of "1" and the gear ratio data
Comparator 15 that inputs EX has a logical value of “0”
The signal is output to the EXNOR circuit 16 at the next stage.

The EXNOR circuit 16 outputs a signal SG2 having a logical value of "0" to the multiplier 17 based on the signals having different logical values.

Then, when the gear ratio data Ex reaches zero, the signal of the comparator 15 becomes "1", and EXNOR
The circuit 16 outputs a signal SG2 having a logical value of "1".

Therefore, even when switching from reverse to forward, the throttle lever of the engine 2 is held in an idling state during deceleration, so it is possible to eliminate the feeling of jumping out due to the lack of acceleration load immediately after switching, and also to eliminate the feeling of jump during deceleration. Engine braking can be applied more effectively. Furthermore, since the engine 2 does not rev up during deceleration, there is no discomfort, there is less noise, and fuel consumption can be kept low.

Second Embodiment The second embodiment is embodied in a forklift similar to the first embodiment, and as shown in Fig. 4.
An OR circuit 22 is provided which inputs the signal SG2 output from the EXNOR circuit 17 and the signal SG3 from the newly provided window comparator 21, and the OR circuit 22 supplies the signal SG4 to the multiplier 17 based on both signals SG2 and SG3. The difference is that it now outputs .

This window comparator 21 inputs the gear ratio data Ex from the ramp signal generation circuit 13,
When the absolute value of the data Ex becomes less than the reference gear ratio data Exs near zero (dead band; when the traveling speed is near 0) shown by the two-dot chain line in Figure 3, a signal with a logical value of "1" Conversely, when the signal SG3 is large, a signal SG3 having a logical value of "0" is output.

Therefore, the next stage OR circuit 22 is connected to the forward/reverse lever 1.
1, when the gear ratio data Ex for deceleration becomes less than the reference gear ratio data Exs (when the traveling speed becomes near zero), the window comparator 21 outputs "1". A signal SG4 having a logical value of "1" is output to the multiplier 17 based on the signal SG3 having a logical value.

That is, in the second embodiment, the engine 2 is controlled to be in an idling state when switching between forward and reverse directions, but when the traveling speed of the forklift is decelerated to around zero, the engine 2 is immediately controlled to be in an idling state according to the rotation speed data A based on the operation of the traveling pedal 1. The rotation of the engine 2 is then controlled.

Therefore, when the forklift shifts from a deceleration state to an acceleration state, the engine 2 has already been activated by the travel pedal 1.
Since the rotation speed is controlled based on the rotation speed, the forklift can be accelerated quickly without any time lag.

Third Embodiment The third embodiment is an example in which a microcomputer is used. In this embodiment, a microcomputer that controls only the continuously variable transmission 3 and the throttle of the engine 2 will be described, but the invention is not limited to this, and this embodiment can also be applied to a microcomputer that controls other drive mechanisms. The example system may be added and implemented.

As shown in FIG. 5, the operation amount signal SG1 and the detection signal from the detector 12 provided on the forward/reverse lever 11 are transmitted to the central processing unit (CPU), a read-only memory (ROM) that stores the control program, and various data. The data is output to the electronic control unit 23, which is composed of a readable and rewritable memory (RAM), etc., in which the data is stored. Based on these signals, arithmetic processing operations are executed according to the flowchart shown in FIG.

At this time, rotation speed data A and gear ratio data E,
Calculation of Ea and Ex, determination of whether Ex is gear ratio data for deceleration, and determination of whether gear ratio data Ex is larger than reference gear ratio data Exs are processed based on a preset program. Further, the throttle actuator 5 and the swash plate actuator 6 are also controlled according to a preset program.

It should be noted that the present invention is not limited to the above-mentioned embodiments, and the continuously variable transmission 3 may be of any type as long as its gear ratio can be changed arbitrarily, such as a V-belt continuously variable transmission.

Alternatively, as shown in FIG. 7, the running pedal 1 may be replaced with a seesaw-type running pedal 19 operated by forward depression when the front is pressed and backward running when the rear depression is operated. In this case, the multiplier 10 becomes unnecessary and the electronic circuit is simplified. Also, in this case,
Although the comparator 14 receives the gear ratio data from the swash plate function generator 9, it may also input the detection signal SG1 from the depression angle detector 7 provided on the pedal 19.

Furthermore, the multiplier 10 that inputs the detection signal from the detector 12 of the forward/reverse lever 11 may be any device that switches the gear ratio data E between plus and minus, and may be a combination of a switch (or relay) and an amplifier, for example. It can be anything. In addition, the gear ratio data Ea of the multiplier 10 is used as one of the data for determining whether the gear ratio data Ex at the time of forward/reverse switching is the gear ratio data Ex for deceleration. It may be implemented in place of the detection signal of the provided detector 12.

Furthermore, the multiplier 17 is an EXNOR circuit 17
Although the signal SG2 from the rotation speed data A is multiplied by the rotation speed data A, this may be performed by a relay. In this case, this relay has a signal SG2 of “0”.
When , it turns off and cuts off the rotational speed data A that is output to the throttle actuator 5, and conversely, when it is 1, it turns on and outputs the rotational speed data A as it is to the throttle actuator 5. .

Further, the engine 2 may be implemented as either a diesel engine or a gasoline engine.

Furthermore, although the throttle actuator 5 and the engine 2 are separated in this embodiment,
This may be integrated with the engine, such as an electronically controlled fuel injection device.

Furthermore, although this embodiment is applied to a forklift, it may also be applied to various cargo handling vehicles such as shovel loaders and aerial work vehicles, trucks, automobiles, and the like.

Effects of the Invention As detailed above, according to the present invention, when switching from forward to reverse or from reverse to forward, the engine throttle is held in an idling state during deceleration, so that the acceleration load immediately after the switch is eliminated. It is possible to eliminate the feeling of jumping out caused by this, and it is also possible to apply the engine brake more effectively during deceleration. Furthermore, since the engine 2 does not rev up during deceleration, there is no discomfort, there is less noise, and fuel consumption can be kept low.

[Brief explanation of drawings]

FIG. 1 is an electric block circuit diagram for explaining the first embodiment of the present invention, FIGS. 2 and 3 are explanatory diagrams for explaining changes in the gear ratio of a continuously variable transmission, and FIG.
The figure is an electric block circuit diagram for explaining the second embodiment of the invention, FIG. 5 is an electric block circuit diagram for explaining the third embodiment of the invention, and FIG. 6 is an electric block circuit diagram for explaining the third embodiment of the invention. FIG. 7 is a flowchart showing the processing operation of the electronic device, and is an electric block circuit diagram for explaining another example of the present invention. Travel pedal...1, Engine...2, Continuously variable transmission...3, Variable displacement hydraulic pump...3a, Hydraulic motor...3b, Throttle actuator...
5, Swash plate actuator...6, Depression angle detector...7, Traveling function generator...8, Swash plate function generator...9, Multiplier...10, 17, Forward/backward lever...11 , detector...12, lamp signal generation circuit...13, comparator...14,15,
EXNOR circuit...16, window comparator...
...21, OR circuit...22, electronic control device...2
3.

Claims (1)

[Claims] 1. The driving wheels are driven by the engine via the continuously variable transmission, and the rotation speed of the engine is controlled based on the amount of operation of the traveling operation device. In a vehicle whose gear ratio is changed based on the operation amount of the travel operating device, and whose gear ratio is changed from a forward to a reverse value or from a reverse to a forward value based on the operation of a forward/reverse operation device, When the gear ratio data value output based on the operation amount changes from a forward to a reverse value or from a reverse to a forward value based on the operation of the forward/reverse operation device, the fluctuation transition of the changing gear ratio data value is a control means for controlling; a first adjustment means for adjusting the gear ratio of the continuously variable transmission based on the gear ratio data value outputted via the control means; and operation of the forward/reverse operating device; Judgment means for determining, based on the speed ratio data value outputted via the control means, whether the speed ratio data value is speed ratio data for deceleration at the time of forward/reverse switching; and and a second adjustment means for adjusting the rotationally controlled engine to an idling state based on the operation amount of the traveling operation device when the speed ratio data value is determined to be the speed ratio data value for deceleration at the time of switching the vehicle forward or backward. Engine rotation control device.