JPH0429862B2 - - Google Patents

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention provides an accelerator pedal that can detect an abnormality in an accelerator pedal sensor that outputs the amount of depression of the accelerator pedal of a vehicle as an electrical signal, and can take measures against the abnormality. The present invention relates to a sensor abnormality processing device.

(Prior Art) In recent years, the introduction of electronic technology to vehicle control has been remarkable, and various mechanically controlled parts have been replaced with electronic control. To use such electronic control, it is necessary to convert the displacement of each part into an electrical signal, and sensors are used for each of these parts. That is, an accelerator pedal sensor is used to detect the amount of accelerator pedal depression by the driver, and as shown in the configuration diagram in FIG. is provided. This sensor 1 has a fixed resistor 11
The sliding contact 12 is fixed to the shaft of a pulley 13, and the rotation of the pulley 20 is transmitted to the pulley 13 by the belt 3.
2 is composed of a potentiometer that slides on a fixed resistor 11. Potentiometers are widely used because they have high resolution and are inexpensive, and can generate the amount of depression of the accelerator pedal 2 (that is, the amount of rotation of the rotating shaft 20a) as an electrical signal called an output voltage. Reference numeral 4a designates an idle switch, and when the accelerator pedal 2 is not depressed, the accelerator pedal 2 is in a position where the upper idle switch 4a is turned on, and idle detection is performed. On the other hand, 4b
is a WOT (wide open) switch, which is turned on when the accelerator pedal 2 is depressed to the maximum. Therefore, the accelerator pedal 2
It is possible to rotate the angle between a and 4b, while the sliding contact 12 rotates through an angle that is twice the diameter ratio of the pulleys 20 and 13. Note that the sliding contact 12 can also be configured to be directly coupled to the rotating shaft 20a of the accelerator pedal 2 and rotated as the rotating shaft 2a rotates.

Sensor 1 and both switches 4 configured in this way
The control unit receives the outputs of a and 4b,
The accelerator pedal sensor is used to determine the amount of accelerator, control the throttle valve and clutch of the engine, and determine the optimum gear. (Problems with the prior art) However, failure of the accelerator pedal sensor does not occur at all. If such a failure occurs while the vehicle is running, it is extremely dangerous because the vehicle operation is controlled by controlling the engine and the like based on the output of the accelerator pedal sensor.

(Object of the Invention) An object of the present invention is to provide an accelerator pedal abnormality processing device that can detect an abnormality of an accelerator pedal sensor that occurs during driving and can deal with the abnormality without causing any danger to vehicle operation. It is in.

(Summary of the Invention) In the present invention, a potentiometer as an accelerator pedal sensor that is linked to the depression of an accelerator pedal has a first position set inward from one end of the maximum operating range, and a first position set inward from the other end of the maximum operating range of the potentiometer. an accelerator pedal, the accelerator pedal having first and second switches regulating a position of the potentiometer and a second position set between the other end, respectively, the operating range of the potentiometer being set between the first and second switches; In the sensor abnormality processing device, a first detection means detects that the output voltage of the potentiometer is at a potential on one end side of the first position; a second detection means for detecting that the potential is closer to the position of the other end than the position; a potentiometer abnormality detection means for receiving signals from these detection means and emitting an abnormal signal; and an abnormality of the potentiometer. When receiving an abnormal signal from the detection means, the first switch is turned on to subtract the current accelerator pedal depression by a predetermined value, and the second switch is turned on to subtract the current accelerator pedal depression by a predetermined value. and arithmetic means for increasing the number.

(Example) FIG. 2 is an explanatory diagram of abnormality determination conditions for an accelerator pedal sensor. Sensor 1 is a sliding contact that can be rotated from 0° to 60°, and the output voltage AP is 0 to 3V for a rotation angle of 0° to 60°.The set standard rotation angle, which is the angle actually used, is Set between 14° and 46°.

Idle switch (ISA) 4a is idle
It becomes ON (open) and turns ON/OFF when the rotation angle of sensor 1 is within the range of 5° to 20°, and OFF when the rotation angle of sensor 1 is between 20° and 50°.
(closed), while WOT switch (WSA) 4
b is set in such a position that it turns ON (closed) when wide open (maximum depression), turns OFF (open) when the rotation angle of sensor 1 is 5° to 37°, and turns ON/OFF at 37° to 50°. .

Therefore, under normal circumstances, the rotation angle of sensor 1 will not generate an output voltage of less than 5 degrees or more than 50 degrees, but if it becomes less than 3 degrees, sensor 1 will be shorted, and if it becomes more than 55 degrees, it will short circuit. Open (broken wire)
shall be.

In other words, when the output voltage AP of sensor 1 becomes less than the voltage DGL (0.15V) corresponding to 3°, the short is 55°.
When the voltage corresponding to DGH (2.75V) or higher is reached, it is determined to be open.

FIG. 3 is an abnormality processing flowchart based on the determination criteria of FIG. 2.

The output voltage AP of the sensor 1 is compared with the lowest voltage value DGL, and if AP<DGL, it is determined that a shot has occurred, and the error counter value ERb is incremented by 1. Next, compare the output voltage AP of sensor 1 and the highest voltage value DGH, and AP>
If it is DGH, it is judged as open and the error counter value is
Add 1 to ERa. and error counter value
If either ERa or ERb exceeds a predetermined set value (5 times), a sensor abnormality warning will be issued, and the accelerator value will be set as described below. That is, if the short or open state continues for a predetermined period of time (multiple times), it is determined that there is an abnormality, thereby preventing misdiagnosis. Furthermore, idle switch 4a and WOT switch 4
It is also possible to detect malfunctions of b. For this purpose, a voltage (1.5V) corresponding to a predetermined rotation angle (for example, 30°) in which both switches 4a and 4b in FIG. 2 are always off is determined as the intermediate voltage DGM, and compared with the output voltage AP. AP
>If it is DGM, idle switch 4a is ON
(open). If it is normal within this output voltage AP range, idle switch 4a is always OFF.
(closed), so idle switch 4a is ON.
If so, it is determined that it is open (broken wire) and 1 is added to the error counter value ERc. Conversely, if AP<DGM, it is detected whether the WOT switch 4b is ON (closed). In this range of output voltage AP, under normal conditions, the
Since WOT switch 4b is OFF (open),
If WOT switch 4b is ON, short circuit
It is determined that 1 is added to the error counter value ERe.
If either the error counter value ERc or ERe exceeds the scheduled setting value (5 times), a switch failure warning will be issued.

FIG. 4 is a block diagram of an embodiment of the present invention, and FIGS. 5 and 6 are process flow diagrams of an embodiment of the present invention.

In FIG. 4, the same parts as in FIG.
Side B is grounded, and two wires are connected between sensor 1 and control unit CTU. Therefore, the idle side has the maximum resistance value, that is, the maximum output voltage, and the WOT side has the minimum resistance value, that is, the minimum output voltage. On the other hand, the sliding contact 12 is connected to the power source E via a resistor R2 having a resistance value that is at least ten times greater than the resistance value of the fixed resistor 11.
Then, the output voltage AP, which is a partial voltage depending on the position of the sliding contact 12 of the sensor 1, is output to the control unit.
It is converted into a digital value AP by an analog-to-digital converter (referred to as AD converter) 5 of the CTU, and is input to a processor (electronic control circuit) 6. The processor 6 uses this digital value AP as an accelerator signal to determine the control amount of the throttle opening of the engine 7, and to turn on/off the clutch 8.
It is used for control and as a condition for speed change control of the automatic transmission 9, and controls the throttle of the engine 7, the clutch 8, and the transmission 9.

Now, the processor 6 of the control unit CTU uses the output voltage AP of the sensor 1 to
Performs abnormality processing. This will be explained with reference to FIGS. 5 and 6. It is assumed that the processor 6 has a built-in memory and uses the memory to perform various arithmetic operations.

The processor 6 first turns on the short detection judgment plug of the memory idle switch 4a.
(“1”), and if it is ON, 1 is added to the idle switch detection error counter value ERd. After that, and when the determination flag is OFF, the determination flag is turned ON. In other words, if the accelerator pedal is depressed before the vehicle's key switch is turned on, the idle switch cannot detect a stop, so the engine starts assuming that a stop has been detected in advance, and the idle switch is turned on later. (See step). Furthermore,
Clear the diagnosis time counter value C to zero,
Finish the initialization step.

Next, processor 6 reads the value of the program timer.
Clear TIME to zero and start the timer. Then, 1 is added to the counter value C. Further, the processor 6 sets the digitized output voltage AP to the accumulator a.

The processor 6 calculates the voltage A of the accumulator a.
and the lowest voltage value DGL, and if A<DGL, it is determined that the sensor is short, and the process proceeds to step.
Conversely, if A≧DGL, the value of a sensor open detection error counter ERa, which will be described later, is set in the accumulator b, and the count value B of the accumulator b is compared with the set number of times "5". If B≧5, it is determined that the sensor is open abnormally and the process proceeds to step. If B<5, then the value of the sensor short detection error counter ERb is set in the accumulator b, and the count value B of the accumulator b is compared with the set number of times "5". B<5
Then, since the sensor shot is not abnormal yet, set the contents of accumulator a to the accelerator value ACCEL,
Proceed to step.

If B≧5, the sensor short is abnormal, so as with the sensor open abnormality and the sensor short,
Let the voltage A of the accimulator a be zero. Next, the processor 6 detects the state of the idle switch 4a, and if the switch 4a is on (open), it subtracts a predetermined value α from the previous accelerator value ACCEL in order to move the throttle valve in the closing direction. Set the accelerator value to ACCEL and proceed to step. Conversely, if the idle switch 4a is off (closed), the processor 6 detects the state of the WOT switch 4b, and if the switch 4b is off (open), the accelerator value ACCEL is left as it was last time, and the process proceeds to step. Conversely, if the switch 4b is on (closed), in order to move the throttle valve in the opening direction, a predetermined value α is added to the previous accelerator value ACCEL, and a new accelerator value ACCEL is set, and the process proceeds to step. That is, when it is determined that there is an abnormality in the step as described above, the idle switch 4
If a is on (open), the accelerator pedal is assumed to be in the idle position regardless of the output of sensor 1, and in order to return the throttle valve to the closed direction, the new accelerator value is set by subtracting α from the previous accelerator value. value. Also, if the idle switch 4a is off (closed) and the WOT switch 4b is off (closed), the previous accelerator value ACCEL is set as the new accelerator value ACCEL, and the WOT switch 4
If b is on (open), the throttle valve is in the opening direction, so the previous accelerator value ACCEL
The new accelerator value is the sum of α. Furthermore, if there is no short or open abnormality in sensor 1, the above steps are not executed, so the output voltage AP of sensor 1 is equal to the accelerator value.
Becomes ACCEL. This determined accelerator value
The processor 6 uses ACCEL to control the engine's throttle valve, determine gears, etc.

Next, the processor 6 sets the counter value C to “4”.
If C=4, the counter value C is set to zero and the process proceeds to the next shoot, the open detection route (FIG. 6). That is, short open detection is performed once every four times. On the other hand, C
If ≠4, proceed to step.

Next, the processor 6 proceeds to the route shown in FIG. 6, detects the state of the idle switch 4a, and checks whether the idle switch 4a is on (open).
If the idle switch 4a is on (open), the determination flag explained in the above step is turned off ("0") and "1" is subtracted from the error counter value ERd.

On the other hand, when the idle switch 4a is off (closed) and after the aforementioned "1" subtraction, the output voltage AP
and the highest voltage value DGH. AP＞DGH
In that case, the sensor is open and the error counter is
Add “1” to the contents of ERa, escape from this route, and proceed to the step. Conversely, if AP≦DGH, the sensor is not open, so "1" is subtracted from the contents of the error counter ERa. The processor 6 then compares the output voltage AP with the lowest voltage value DGL. If AP<DGL, sensor shoot is performed, "1" is added to the contents of error counter ERb, this route is exited, and the process proceeds to step. Conversely, if AP≧DGL, it is determined that there is no sensor shot, and “1” is subtracted from the contents of the error counter ERb.

Next, the processor 6 proceeds to detect an abnormality in the switches 4a and 4b. Processor 6 outputs voltage
Compare AP and intermediate voltage value DGM. AP>
If it is a DGM, it is detected whether the idle switch 4a is on (open) or not. If it is on, the switch is considered open and "1" is added to the error counter ERc, and if it is off, the switch is not open, so the error counter ERc is added. Subtract "1" from the value of , escape from this route, and proceed to the step. Conversely, if AP≦DGM, it is detected whether the state of the WOT switch 4b is on (open) or not, and if it is on, it is considered a switch and "1" is added to the value of the error counter ERe, and if it is off, it is not a switch, so Subtract "1" from the value of the error counter ERe, escape from this route, and proceed to the step.

Next, processor 6 sets the timer value TIME to 25m.
Detect whether s has elapsed and when TIME=25,
Return to step.

Therefore, the signal processing route in Figure 5 is executed every 25ms, and the failure detection route in Figure 6 is executed every 100ms (=
25ms x 4 times), and if shoot or open is detected 5 times by the detection route shown in Fig. 6, that is, if shoot or open continues for 0.5 sec (5 times x 100ms), Fig. 5 It is determined that the route is abnormal, and a pseudo signal is generated to back up the accelerator pedal sensor.

In addition, in the route shown in Fig. 5, the abnormality warning is carried out in a route not shown separately under the condition of B≧5, for example,
It is displayed on the driver's seat display panel or on a separately installed diagnostic device.

Although omitted in the flow diagram, each determination counter is never subtracted from 0, nor is it incremented from an appropriate value of 5 or more.

(Effects of the Invention) As explained above, according to the present invention, the determination is made by detecting that the output voltage of the accelerator pedal sensor composed of a potentiometer is outside a predetermined voltage range. This has the effect of being able to detect an abnormality in the accelerator pedal sensor while driving, and when an abnormality is detected, a predetermined value is added or subtracted from the previous accelerator value depending on the state of the idle switch and wide open switch, and a value is generated as the accelerator amount. As a result, the back-up of the accelerator is gradually set to the optimal value according to the state of the switch that is not abnormal, so the vehicle speed accelerates or decreases smoothly, allowing the vehicle to drive to a safe area. be effective.

Although the present invention has been described with reference to one embodiment, various modifications can be made within the scope of the present invention, and these are not excluded from the scope of the present invention.

[Brief explanation of drawings]

Fig. 1 is a configuration diagram of a sensor, Fig. 2 is an explanatory diagram of judgment criteria for the device of the present invention, Fig. 3 is an explanatory diagram of the principle of the device of the present invention, and Fig. 4 is an implementation for realizing the method of the present invention. The example block diagram, FIGS. 5 and 6, are process flow diagrams of one embodiment of the apparatus of the present invention. In the figure, 1... accelerator pedal sensor, 2... accelerator pedal, 4a... idle switch, 4b
...WOT switch, CTU...control unit.

Claims (1)

[Claims] 1. A first position set inward from one end of the maximum operating range of a potentiometer as an accelerator pedal sensor linked to depression of the accelerator pedal, and the first position set inward from the other end. and the other end of the accelerator pedal sensor, the accelerator pedal sensor having first and second switches regulating a second position set between the first and second ends, respectively, the operating range of the potentiometer being set between the first and second switches. In the abnormality processing device, a first detection means detects that the output voltage of the potentiometer is at a potential on one end side of the first position; a second detection means for detecting that the potential is at the other end position side; a potentiometer abnormality detection means for receiving signals from these detection means and generating an abnormality signal; and an abnormality detection means for the potentiometer. When an abnormal signal is received from the first switch, the current accelerator pedal depression amount is subtracted by a predetermined value by turning on the first switch, and the current accelerator pedal depression amount is increased by a predetermined value by turning on the second switch. 1. An abnormality processing device for an accelerator pedal sensor, comprising a calculation means. 2. A counting means for counting the number of times the value of the potentiometer is outside a predetermined range, and an abnormality detection means for outputting the value of the potentiometer to the calculating means when the count value of the counting means reaches a predetermined number of times. An abnormality processing device for an accelerator pedal sensor according to claim 1, characterized in that it has the following. 3. A patent characterized in that it has a depression amount signal maintaining means that detects that the value of the potentiometer is outside a predetermined range and maintains the signal before the detection by turning off the first and second switches. An abnormality processing device for an accelerator pedal sensor according to claim 1.