JPH0322332B2 - - 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 drives drive wheels by an engine 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. or from reverse to a forward value, 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 a forward 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, determining the rotation speed of the engine whose rotation is controlled based on the operation amount of the traveling operation device; The gist of the present invention is an engine rotation control device during switching between forward and backward movement of a vehicle, which comprises a second adjustment means that performs variable adjustment based on a speed ratio data value for deceleration.

(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 to reverse value or from the reverse to the forward value. When the gear ratio data value changes, the control means controls the change in the changing gear ratio data value, and the first adjusting means adjusts the gear ratio of the continuously variable transmission based on the controlled gear ratio data value.

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 as to 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 adjusting means varies the rotational speed of the engine controlled based on the operation amount of the travel operation device based on the gear ratio data value for deceleration. It was designed to be adjusted.

(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 that adjusts the rotational speed of the engine 2 is controlled by a throttle actuator 5.

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 implemented using 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 rotation speed data A is multiplied by a multiplier 18, which will be described later, and is output to the throttle actuator 5 as corrected rotation speed data Ax. Then, the actuator 5 adjusts the throttle based on the data Ax to control the rotational speed of the engine 2 based on the data Ax.

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 gear ratio data E for controlling the inclination 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 driving.

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 a sensor that detects the vehicle speed, a sensor that detects the load during driving, or the selection operation of a 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 the figure, three variable speed ratios (rising and falling lines La1 to La3, Ld1 to Ld3) are prepared and can be appropriately selected by the driver in advance.

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 is The ratio data Ex is the gear ratio data Ex for starting the forklift's backward travel and accelerating it to a predetermined gear ratio.
It turns out that.

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 Ex 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 Ex for starting the forward movement of the forklift and accelerating 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, 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 to each other, that is, when the gear ratio data Ex is fluctuating due to acceleration as shown in FIG. The value is "1"
The signal SG2 is output.

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.

Signal SG2 from EXNOR circuit 16 is output to correction function generator 17. The correction function generator 17 inputs the gear ratio data value Ex, and outputs the same data value Ex.
is a circuit that converts the signal SG2 into correction data D for correcting the engine rotation speed controlled based on the engine rotation speed data A, and when the logic value of the signal SG2 is "0", a predetermined function is converted. The gear ratio data Ex is converted into correction data D based on , and when the logical value of the signal SG2 is "1", the correction data D having a value of 1 is output.

The function of the correction data D with respect to the speed ratio data Ex is set in advance, and the value of the correction data D changes in the range of 0 to 1 with respect to the value of the speed ratio data Ex. In this embodiment, the fourth
As shown in the figure, three functions F1 to F3 are prepared,
Determine the current driving conditions and cargo handling conditions based on a sensor that detects the presence and weight of luggage, a sensor that detects vehicle speed, a sensor that detects the load during driving, or the selection operation of a selection switch by the driver. The optimal function that meets the conditions is then selected. Note that function F1 is the one that makes the correction data D inversely proportional to the traveling speed, function F2 is the one that increases the amount of throttle down at medium and high speeds, and function F3 is the one that increases the amount of throttle down at medium and high speeds. This is a function provided.

Therefore, the correction function generator 17 is the EXNOR circuit 1
When the signal SG2 of 6 is "0", the same function generator 17
The correction data D for the gear ratio data Ex is output according to a predetermined function, and when the signal SG2 is "1",
Correction data D with a value of 1 is always output regardless of the gear ratio data Ex.

The correction data D is output to the next stage multiplier 18,
The multiplier 18 inputs the rotation speed data A and the correction data D.
The result of the calculation is output to the throttle actuator 5 as corrected rotational speed data Ax.

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 gear ratio as shown in FIG. Therefore, the gear ratio data Ex
The forklift is decelerated until the value of decreases to zero. At this time, smooth deceleration characteristics without impact can be obtained by changing the gear ratio.

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 correction function generator 17 based on the signals having different logical values. The correction function generator 17 converts the gear ratio data Ex outputted from the ramp signal generator 13 into correction data D according to a preselected function based on the signal SG2 having a logical value of "0", and converts the gear ratio data Ex outputted from the ramp signal generator 13 into correction data D. Output to multiplier 18.

The multiplier 18 multiplies this correction data D and rotation speed data A, and uses the corrected rotation speed data as a result of the calculation.
Ax is output to the throttle actuator 5.
At this time, the corrected rotation speed data Ax has a value smaller than the rotation speed data A since the correction data D has a value smaller than 1. As a result, the engine 2 is controlled to a corrected rotation speed that is lower than the rotation speed based on the rotation speed data A.

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 sends the signal SG2 having a logic value of "1" to the correction function generator 1.
Output to 7. The correction function generator 17 receives this signal.
In response to SG2, correction data D having a value of 1 is output to the multiplier 18. A multiplier 18 multiplies this correction data D and rotation speed data A. As a result, the values of the rotation speed data A and the corrected rotation speed data Ax become the same, and the value of the rotation speed data A based on the operation of the travel pedal 1 is output as is to the throttle actuator 5, and the rotation speed of the engine 2 is is controlled based on the amount of operation of the travel pedal 1. 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,
Since the gear ratio changes at a predetermined speed ratio, smooth and optimal acceleration characteristics can be obtained.

Therefore, when decelerating when switching from forward to reverse, the rotational speed of the engine 2, which is controlled according to the amount of operation of the travel pedal 1, is determined by the variable gear ratio data.
Since it is corrected to a small value based on the value of Ex, it is possible to eliminate the sudden feeling that occurs due to the lack of acceleration load immediately after switching, 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.

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 controller changes at a predetermined gear ratio. 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 correction function generator 17 based on the signals having different logical values. In response, the correction function generator 17 outputs correction data D for the gear ratio data -Ex to the multiplier 18 at the next stage.

Furthermore, when the gear ratio data Ex reaches zero, the signal of the comparator 15 becomes "1", and the EXNOR circuit 16 outputs the signal SG2 with the logical value of "1", so the correction function generator 17 outputs the signal with the logical value of "1". The correction data D will be output to the multiplier 18.

Therefore, even when switching from reverse to forward, the rotational speed of the engine 2, which is controlled by the operating amount of the travel pedal 1, is corrected to a small value during deceleration based on the variable gear ratio data - Ex. ,
It is possible to eliminate the sudden feeling that occurs due to the lack of acceleration load immediately after switching, 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.

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

Further, as shown in FIG. 5, the running pedal 1 may be replaced with a seesaw-type running pedal 19 which is operated by pressing forward to move forward and pressing backward to move backward. In this case, the multiplier 10 becomes unnecessary and the electronic circuit is simplified. Also, in this case,
The comparator 14 receives gear ratio data E from the swash plate function generator 9, which is input to the pedal 19.
Detection signal SG1 from the depression angle detector 7 provided in
You may also enter

Further, in this embodiment, the correction function generator 17 outputs the correction data D based on the gear ratio data Ex, but this is converted into the optimum engine rotation speed data during deceleration. Then, the multiplier 18 in the next stage is replaced with a minimum value selector, the rotation speed data A and the rotation speed data output from this function generator 17 are compared in magnitude, and the smaller one is output to the throttle actuator 5. The rotational speed of the engine 2 may also be controlled.

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.

Second Embodiment The second embodiment is an example in which a microcomputer is used. In this embodiment, a microcomputer that only controls the continuously variable transmission 3 and the throttle actuator 5 will be described, but the present invention is not limited to this, and the microcomputer that controls other drive mechanisms can also be used. The example control system may be added and implemented.

As shown in FIG. 6, 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 21, 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, gear ratio data E,
Calculation of Ea, Ex, correction data D, and correction rotational speed data Ax, as well as determination of gear ratio data Ex for deceleration, 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.

Note that the present invention is not limited to the above-mentioned embodiments, and for example, the engine 2 may be a diesel engine or a gasoline engine.

Furthermore, although the throttle actuator 5 and the engine 2 are separated from each other in the above embodiments, they may be integrated with the engine, such as an electronically controlled fuel injection system.

Furthermore, although the above embodiments are applied to a forklift, the present invention 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, when decelerating, the engine speed controlled based on the operation amount of the travel control device is controlled by the gear ratio data. Since it is corrected to a small value based on the changeover, it is possible to eliminate the sudden feeling that occurs due to the lack of acceleration load immediately after switching, 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 the drawing]

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 shows the function of the correction data D for the gear ratio data Ex, FIG. 5 is an electric block circuit diagram for explaining another example of the first embodiment, and FIG. 6 explains the second embodiment of the present invention. FIG. 7 is a flowchart showing the processing operation of the electronic device of the second embodiment. 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, Travel function generator...8, Swash plate function generator...9, Multiplier...10, 18, Forward/backward lever...11 , detector...12, lamp signal generation circuit...13, comparator...14,15,
EXNOR circuit...16, correction function generation circuit...1
7. Electronic control unit...21.

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/forward switching; a second adjusting means that variably adjusts the rotational speed of the engine whose rotation is controlled based on the operation amount of the traveling operation device based on the speed ratio data value for decelerating the engine when the speed ratio data value is determined to be the speed ratio data value; , An engine rotation control device when switching forward or backward of a vehicle.