JPH0379541B2 - - Google Patents

Description

[Detailed description of the invention]

The present invention relates to an accelerator control device for a vehicle, and more particularly to an accelerator control device that changes the characteristics of the accelerator pedal depression feeling and acceleration feeling in accordance with driving conditions. As is well known, in automobiles, the accelerator pedal and the throttle valve are directly mechanically connected by wires, links, etc., and the opening degree of the throttle valve is uniquely determined by the amount of depression (displacement, stroke) of the accelerator pedal. It is configured to be determined. In this mechanical accelerator system, in order to obtain a good feeling of acceleration in which a slight acceleration of the accelerator pedal is rapidly accelerated, the rate of change of the throttle valve opening relative to the amount of displacement of the accelerator pedal is set to a large value. Fine control of speed becomes difficult. On the other hand, if the rate of change of the throttle valve opening with respect to the amount of displacement of the accelerator pedal is set small with emphasis on fine controllability of speed during low-speed running, the feeling of acceleration in response to pedal operation will deteriorate. As described above, conventional accelerator systems have not been able to provide characteristics that make driving easy under all driving conditions. This invention was made in view of the above-mentioned conventional problems, and its purpose is to reduce the rate of change of the throttle valve opening relative to the displacement of the accelerator pedal when the pedal is operated slowly in order to finely adjust the speed. It is an object of the present invention to provide an accelerator control device in which the change rate is automatically reduced, and in other cases, the change rate is automatically set to a relatively large change rate that provides a sufficient feeling of acceleration. In order to achieve the above object, the present invention provides a servo drive means for a throttle valve that opens and closes the throttle valve so that the valve opening corresponds to a given control signal, and detects the displacement amount of an accelerator pedal. A pedal stroke detection means is set with a plurality of different characteristics that are approximately proportional to the relationship between the displacement amount of the accelerator pedal and the opening of the throttle valve, and the throttle valve opening is controlled in accordance with the output of the stroke detection means. The basic configuration includes control signal generating means for outputting a signal and applying the control signal to the servo driving means. In addition to this, the operation start detecting means detects the timing when the accelerator pedal starts to be displaced from the zero position, the timer means measures a predetermined period of time from the time of detection by the operation start detecting means, and the timer means a first operation status determining means for determining whether one or both of the displacement amount and displacement speed of the accelerator pedal exceeds a preset first reference value during the measurement of the certain period of time by the accelerator; a second operation status determining means for determining whether one or both of the displacement amount and the displacement speed of the pedal exceeds a second reference value that is larger than a preset first reference value; If the operation status determination means detects that the first reference value has not been exceeded within the above-mentioned certain period of time, the second operation status determination means detects that the second reference value has been exceeded. is a control characteristic change in which the rate of change in the valve opening relative to the displacement in the accelerator pedal displacement/throttle valve opening characteristic in the control signal generating means is made relatively small, and in other cases, the rate of change is made relatively large. It is characterized by providing means. In other words, the present invention focuses on the fact that when the pedal is operated with the intention of finely adjusting the speed, the amount of pedal displacement and the displacement speed are kept within a very small range within a very short time after the accelerator pedal is depressed. Such a pedal operation situation is detected using the first reference value, and the rate of change of the throttle valve opening degree with respect to the amount of pedal displacement is automatically reduced. Further, after the rate of change is reduced, when the driving situation changes and the need for fine adjustment of the speed is eliminated, and the driver depresses the accelerator pedal greatly or quickly, such a pedal operation situation can be changed to a second one. It is detected based on the reference value and the rate of change is automatically increased again. Hereinafter, embodiments of the present invention will be described in detail based on the drawings. FIG. 1 is a block diagram showing the hardware configuration of an embodiment of an accelerator control device according to the present invention. In this system, microcomputer 1
A control signal (target value of throttle valve opening) is applied from the D/A converter 2 to the servo drive system of the throttle valve. This servo drive system includes a servo motor 3 that drives the throttle valve to open and close, a valve opening sensor 4 consisting of a potentiometer, etc. that detects the opening of the throttle valve, and a microcomputer 1.
The servo drive circuit 5 includes a servo drive circuit 5 that drives the servo motor 3 in forward and reverse rotation so that the control signal given from the valve opening sensor 4 matches the detection output of the valve opening sensor 4. In connection with the accelerator pedal, there is a stroke sensor 6 consisting of a potentiometer or the like that detects the amount of displacement of the accelerator pedal, and a zero position detection switch 7 that is turned on when the accelerator pedal returns to the zero position due to the force of a spring or the like. is provided. A pedal displacement signal APS detected by the stroke sensor 6 is read into the microcomputer 1 via an A/D converter. Further, the pedal displacement amount signal APS is differentiated by a differentiating circuit 9 to obtain a pedal displacement speed signal DAPS, and this displacement speed signal DAPS is obtained.
DAPS is also read into the microcomputer 1 via the A/D converter 8. Further, the timing at which the zero position detection switch 7 changes from ON to OFF, that is, the timing at which the accelerator pedal starts to be depressed from the zero position, is detected by the rise detection circuit 10, and the operation is started by a pulse with a minute width in response to this timing. pulse
AOT is generated, and this signal AOT is also read into the microcomputer 1. The microcomputer 1 performs control and arithmetic processing according to the above-mentioned accelerator pedal displacement signal APS, displacement speed signal DAPS, and operation start pulse AOT, and determines the target value of the throttle valve opening to be applied to the servo drive circuit 5. Output. The throttle valve opening (target value) is set in advance using the accelerator pedal displacement signal APS as an input variable, and is stored in the memory of the microcomputer 1 in the form of a function table. Regarding the functional relationship between accelerator pedal displacement and throttle valve opening, there are two types of characteristics as shown in Figure 3.
CB1 and CB2 are set and stored in the microcomputer 1. In this embodiment, both characteristics CB1 and CB2 have linear characteristics in which the throttle valve opening increases in proportion to the amount of displacement of the accelerator pedal. One of these characteristics, CB1, is selected to have almost the same characteristics as a conventional accelerator system in which the accelerator pedal and throttle valve are directly connected mechanically, and the rate of change in the throttle valve opening with respect to the amount of displacement of the accelerator pedal is relatively large. (Characteristics with good acceleration feeling). On the other hand, the other characteristic CB2 is a characteristic for facilitating fine adjustment of the speed, and the rate of change of the stroke valve opening relative to the accelerator pedal displacement is set to be small. In the case of the accelerator control device of the present invention, in a normal state other than the cases described below, the above characteristics
The throttle valve opening degree is controlled in accordance with CB1.
The throttle valve opening degree is controlled by changing to the characteristic CB2 for fine speed adjustment in the following cases. Depressing the accelerator pedal is started when the accelerator pedal has returned to the zero position, and the displacement signal APS of the accelerator pedal does not exceed the preset reference value APS1 within a sufficiently small fixed time T ₀ from the operation start timing. Further, when the displacement speed signal DAPS of the accelerator pedal does not exceed a preset reference value DAPS1, the control characteristic after the time _T0 is changed to a characteristic CB2 suitable for fine speed adjustment. However, even if the speed fine adjustment characteristic CB2 is changed, the accelerator pedal displacement signal APS
The second reference value APS2 (>APS1) set in advance
or the accelerator pedal displacement speed signal DAPS exceeds a preset second reference value DAPS2.
(>DAPS1), it is determined that the driving situation has changed and the driver wants operability with a good sense of acceleration, and the control characteristic is returned to the characteristic CB1, which has a large rate of change. The above situation is shown in the time chart of FIG. When the accelerator pedal is depressed from the zero position, the microcomputer 1 generates the operation start pulse AOT as explained earlier.
In response to AOT, a timer is activated to count the minute constant time T ₀ mentioned above. In addition, while the timer is measuring time T ₀ , the latest displacement signal APS and displacement speed signal DAPS, which are repeatedly sampled, are compared with the reference values APS1 and DAPS1, respectively, and the APS continues during time T ₀ . <APS1 When DAPS<DAPS1, the control characteristics become characteristic after time _T0 .
Changed to CB2. otherwise characteristic CB
Control is performed with the value set to 1. In addition, as shown in Figure 4, the control characteristics
Even after CB2 is selected, the microcomputer 1 continues to update the latest accelerator pedal displacement signal APS, displacement speed signal DAPS, and second reference value APS2.
When APS>APS2 or DAPS>DAPS2, the control characteristics are returned to the normal characteristics CB1. The first reference values APS1 and DAPS1 for selecting the characteristic CB2 mentioned above and the control characteristic from CB2 are used.
Second reference value APS2, DAPS to return to CB1
Regarding No. 2, FIG. 5A shows a graph in which the horizontal axis represents the displacement APS of the accelerator pedal, and the vertical axis represents the displacement speed DAPS. In this diagram,
In region R1, the displacement amount signal APS is smaller than the reference value APS1, and the displacement speed signal DAPS is the reference value.
It shows an area smaller than DAPS1, and _APS ,
Characteristic CB when DAPS does not exceed area R1
2 is selected. In addition, region R2 is a displacement signal
This is the region where APS exceeds the reference value APS2 or the displacement speed signal DAPS exceeds the reference value DAPS2, and even after characteristic CB2 is selected, APS,
When DAPS enters region R2, characteristic CB again
It is returned to 1. Above, standard values APS1, APS2, DAPS1,
DAPS2 is a reference value for the displacement amount and displacement speed when operating the accelerator pedal with the intention of finely adjusting the speed and accelerating the vehicle, and is experimentally determined.
% value, APS2 has a similar value of 40%, and
DAPS1 is set to a speed that allows a full pedal stroke to be achieved in 1 second, and DAPS2 is set to a speed that allows the same to be achieved in 0.5 seconds. This is done by focusing on the correlation between An example of a specific processing procedure for realizing the above control performed by the microcomputer 1 is shown in the flowchart of FIG. As shown in Figure 2, the microcomputer 1
is the accelerator pedal displacement signal at step 140.
APS is read, and in the following step 141, the target value of the throttle valve opening corresponding to the read displacement signal APS is determined, and in the following step 142, the target value is output to the servomechanism circuit 5 to set the target throttle valve opening. Make it equal to the value. The characteristic used to calculate the valve opening target value in step 141 is based on either characteristic name CB1 or CB2 stored in register CB as described later.
A target value of the throttle valve opening corresponding to the displacement signal APS is calculated using one of the function tables of the characteristics CB1 and CB2 and using well-known table lookup and interpolation processing techniques. In addition to storing the characteristic name CB1 in the register CB in the initialization process at step 101, the characteristic name CB1 is stored in steps 130, 132, and 152, which will be explained in sequence below, and the characteristic name CB2 is stored in the register CB in step 131. Stored in First, when the accelerator pedal operation start pulse AOT is detected in step 110, the process proceeds to step 111, where a flag FFAOT indicating that the pulse AOT has been detected is detected.
is already set to “1” or not,
If flag FFAOT is not set, proceed to step 112 to set it, followed by step 112.
At step 113, a timer for counting the above-mentioned time _T0 is activated. Note that if it is detected in step 111 that the flag FFAOT has already been set,
Skip steps 112 and 113. After starting the timer in step 113, the accelerator pedal displacement signal APS and displacement speed signal DAPS are read in step 120, and in the following step 121, whether the displacement signal APS is greater than or equal to the reference value APS1 or the displacement speed signal DAPS is the reference value DAPS1. If either of the values is greater than or equal to the reference value (outside area R1), the timer is stopped in step 124, and the register CB is stopped in step 132.
Store CB1 in . Also, in step 121, both data are APS1,
If it does not exceed DAPS1 (within area R1),
Proceeding to step 122, it is checked whether the timer counting the time _T0 has timed up. Until this timer times up, the process proceeds to step 130 and stores CB1 in register CB. Also, in step 110, the operation start pulse AOT is
is flagged in step 114 even if it is not detected.
After resetting FFAOT to "0", it is checked in the subsequent step 115 whether or not the above-mentioned timer has been started, and if this timer is counting time _T0 , the process proceeds to the previous step 120 and onwards. After the operation start pulse AOT is generated, the accelerator pedal displacement signal APS and displacement speed signal are
If the time _T0 elapses without both DAPS exceeding the reference values APS1 and DAPS1 and the timer times out, the determination in step 122 is YES. In this case, the timer is stopped in step 123, and the register CB is set in step 131. Characteristic name CB suitable for fine speed adjustment
2 is stored. If it is detected in step 115 that the timer is stopped, the process proceeds to step 150, where the accelerator pedal displacement signal APS and displacement speed signal DAPS are read, and the process proceeds to step 151.
Checks whether the displacement amount signal APS is above the reference value APS2 and whether the displacement speed signal DAPS is above the reference value DAPS2. If either one is above the reference value (within area R2), register CB is checked in step 152. Store the characteristic name CB1 in . The process of selecting the above characteristics and the next step 140
→141→142 processing is executed repeatedly at high speed,
Control of the accelerator control device according to the present invention described above is realized. Here, additional notes will be made regarding other embodiments of the present invention. The method of setting regions R1 and R2, which serve as criteria for selecting the above-mentioned characteristics, is not limited to that shown in FIG. It is. For example, in the previous embodiment, when both the pedal displacement amount and the displacement speed do not exceed the reference values within a certain period of time after the pedal is operated, characteristic CB2 for fine speed adjustment is selected. Even if only one of the displacement amount and the displacement speed is set and the characteristic CB2 is selected when it does not exceed the reference value, the intended effects of the present invention can almost be achieved. In addition, the control characteristics were changed to CB2
Regarding the reference range R2 for returning from to CB1,
For example, settings can be made as shown in FIG. 5B. Comparing this with A, even if the displacement amount of the accelerator pedal exceeds the reference value APS2, if the displacement speed is very small and is less than the reference value DAPS3, control will be performed with characteristic CB2. . In addition, in the flowchart of FIG. 2, if the above-mentioned timer is counting time at step 122 and the determination is NO, the program proceeds to step 140 without executing step 130, which stores CB1 in register CB. For example, while the timer is counting time, the previously selected characteristic continues to be selected. Therefore, a separately provided switch may be used to select whether to execute or skip step 130. Further, even without providing the zero position detection switch 7, the same function can be achieved using the output of the stroke sensor 6. In other words, the stroke sensor 6 when the accelerator pedal is at the zero position
For example, the output of the accelerator pedal can be discriminated by a comparator to extract the timing when the accelerator pedal is depressed from the zero position. Further, the stroke sensor 6 is not limited to one using a potentiometer, and various position and displacement detectors such as a rotary encoder can be used. Further, the servo drive system for the throttle valve is not limited to an electric mechanism using the servo motor 3, but the same function can be achieved by a servo system using hydraulic or pneumatic pressure. Furthermore, the characteristics of accelerator pedal displacement/throttle valve opening are not limited to the straight line shown in Fig. 3, and other curved characteristics may be selected according to the throttle valve characteristics and the characteristics of the servo drive system. . Furthermore, it is also possible to set three or more characteristics of accelerator pedal displacement amount/throttle valve opening degree, and to develop the invention so that the characteristics are selected based on other factors in combination with the present invention. Furthermore, it goes without saying that the calculation function for obtaining the target value of the throttle valve opening based on predetermined characteristics from the displacement amount signal of the accelerator pedal can also be realized by a separate analog calculation circuit using a function generator. As explained in detail above, according to the present invention, when the driver performs a fine accelerator operation with the intention of finely controlling the speed, the change rate characteristic of the throttle valve opening with respect to the displacement amount of the accelerator pedal is automatically changed. This makes it much easier to make minute adjustments to the speed, and unlike in the past, a slight change in the accelerator pedal would cause the engine torque to change more than necessary, causing the unpleasant feeling of the car body jerking when driving in traffic jams. It also eliminates fatigue and irritation caused by minute foot movements.
In addition, even if the rate of change in the throttle valve opening with respect to the displacement of the accelerator pedal has become small, if you operate the pedal normally without intending to make fine adjustments, it will of course operate with good acceleration characteristics. be.

[Brief explanation of drawings]

FIG. 1 is a block diagram showing the configuration of an accelerator control device according to an embodiment of the present invention, FIG. 2 is a flowchart showing the contents of control by the microcomputer 1 in FIG. 1, and FIG. Figure 4 is a time chart showing an example of the operation of the above device;
FIGS. 5A and 5B are diagrams showing examples of setting reference ranges for selecting control characteristics. 1... Microcomputer, 3... Servo motor, 4... Valve opening sensor, 5... Servo drive circuit, 6... Stroke sensor, 7... Zero position detection switch, 9... Differential circuit, 10... Rise detection circuit, AOT...operation start pulse, APS...displacement amount signal, DAPS...displacement speed signal.

Claims (1)

[Scope of Claims] 1. Throttle valve servo drive means for opening and closing the throttle valve so that the valve opening corresponds to a given control signal; Pedal stroke detection means for detecting the amount of displacement of the accelerator pedal; A plurality of different characteristics that are approximately proportional to the relationship between the displacement amount of the accelerator pedal and the opening degree of the throttle valve are set, and a control signal for the throttle valve opening degree corresponding to the output of the stroke detection means is outputted. A control signal generation means for supplying a control signal to the servo drive means; an operation start detection means for detecting the timing when the accelerator pedal starts to be displaced from the zero position; and a predetermined time period from the time of detection by the operation start detection means. a timer means; and a first means for determining whether or not the displacement amount and/or displacement speed of the accelerator pedal exceeds a preset first reference value while the timer means measures the above-mentioned fixed time. an operating status determining means; a second operating status determining unit for determining whether one or both of the displacement amount and displacement speed of the accelerator pedal exceeds a second reference value that is greater than a preset first reference value; If the first operation status determination unit detects that the first reference value has not been exceeded within the certain period of time, the second operation status determination unit determines that the second reference value has not been exceeded. Until this is detected, the rate of change in the valve opening with respect to the displacement of the accelerator pedal displacement/throttle valve opening characteristic in the control signal generating means is made small, and in other cases, the rate of change is made large. An accelerator control device for a vehicle, comprising: control characteristic changing means;