JP4072198B2 - Automatic transmission failure diagnosis device - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention belongs to the technical field of a failure diagnosis device for an automatic transmission mounted on a vehicle.
[0002]
[Prior art]
Conventionally, an ATCU (AT control unit) that detects a throttle pulse signal output from a throttle opening sensor via an ECU (engine control unit) and controls an automatic transmission based on the throttle pulse signal is known. .
[0003]
FIG. 4 shows a circuit configuration diagram relating to throttle pulse signals of the ECU and ATCU. The ATCU detects the voltage value of the throttle pulse signal based on the throttle signal output from the ECU. More specifically, as shown in FIG. 5 (a), the Hi level and Low level of the voltage value of the throttle pulse signal are determined, and the Hi level time and Low level time of the pulse are measured by the input processing logic. Based on this time, the throttle opening is determined, and when the Hi level and the Low level cannot be discriminated, it is determined that the throttle opening sensor has failed. When the ATCU determines that a throttle opening sensor failure has occurred, the ATCU stores a failure code in a memory referred to during vehicle inspection, displays a warning to the driver by lighting a warning light, and the like.
[0004]
[Problems to be solved by the invention]
The following is an example of determining the failure of the throttle opening sensor in the conventional ATCU.
[0005]
[When the ignition power supply voltage drops]
FIG. 5B shows the waveform of the pulse signal when the voltage of the ignition power supply that supplies the voltage to the throttle opening sensor drops. As shown in the figure, when the voltage value of the ignition power supply decreases, the ATCU cannot perform the Hi level determination if the power supply voltage value becomes equal to or lower than the Hi level determination voltage.
[0006]
[When ignition key is off]
FIG. 6 is a time chart showing control when the ignition key of the ECU and ATCU is turned off.
[0007]
At t1, the ignition power supplied to the ECU and ATCU is shut off by turning off the ignition key. Normally, when the power is turned off, a CPU reset occurs after storing necessary information and the ECU and ATCU are stopped. However, since the CPU reset generation voltage differs between the ECU and the ATCU, when the throttle pulse signal corresponding to the throttle signal is output from the ECU to the ATCU, the CPU reset of the ECU occurs before the ATCU.
[0008]
At t2, the CPU reset of the ECU occurs, and the output of the throttle pulse signal based on the throttle signal from the ECU to the ATCU stops. At the same time, the ATCU will not detect the throttle pulse signal.
[0009]
At t3, since the predetermined time has passed since the ATCU no longer detects the throttle pulse at t2, the ATCU erroneously determines that the throttle opening sensor has failed, and sets the fail-safe execution flag and the driver warning flag, and the failure code Remember.
At t4, an ATCU CPU reset occurs.
[0010]
The misjudgment described above is caused by a difference in the reset sequence of each control unit when the ignition power is turned off. Therefore, there is no abnormality in the signal lines and the ECU output, and it is highly possible that the cause will be unknown even after investigation.
[0011]
The present invention has been made paying attention to the problems of the prior art described above, and the object of the present invention is to prevent erroneous determination and false alarm of throttle opening sensor failure due to voltage drop and key-off of the ignition power supply. Another object of the present invention is to provide an automatic transmission failure diagnosis device capable of improving the accuracy of throttle opening sensor failure diagnosis.
[0012]
[Means for Solving the Problems]
As means for solving the above-described problem, in the invention according to claim 1, in the automatic transmission that performs shift control based on a throttle signal that is a detection value of a throttle opening sensor,
Throttle opening sensor abnormality determining means for detecting a throttle pulse signal based on the throttle signal and determining abnormality of the throttle opening sensor;
Power supply voltage value detection means for detecting the voltage value of the power supply of the throttle signal;
When the throttle opening sensor abnormality determination means does not detect a throttle pulse signal based on the throttle signal, and the power supply voltage value of the throttle signal detected by the power supply voltage value detection means is greater than or equal to a preset set value In addition, a throttle opening sensor failure diagnosis means for determining that the throttle opening sensor has failed,
It is characterized by providing.
[0013]
According to a second aspect of the present invention, in the automatic transmission failure diagnosis device according to the first aspect,
The throttle opening sensor outputs a throttle signal to the engine control unit,
The engine control unit outputs a throttle pulse signal based on the throttle signal to the throttle opening sensor abnormality determining means,
The throttle opening sensor abnormality determining means detects the throttle pulse signal to determine abnormality of the throttle opening sensor.
[0014]
[Action and effect of the invention]
According to the first aspect of the present invention, the throttle opening sensor failure diagnosing means does not detect the throttle pulse signal based on the throttle signal by the throttle opening sensor abnormality determining means, and detects the throttle signal detected by the power supply voltage value detecting means. When the voltage value of the power source is equal to or higher than a preset value, it is determined that a failure has occurred in the throttle opening sensor. On the other hand, even if the throttle opening sensor abnormality determining means does not detect the throttle pulse signal based on the throttle signal, if the power supply voltage value of the throttle signal detected by the power supply voltage value detecting means is less than the set value, the throttle It is not determined that the opening sensor has failed. That is, only when the voltage value is equal to or higher than the set value, the failure code is stored and a warning is displayed to the driver.
[0015]
Therefore, in the present invention, it is possible to prevent erroneous determination of the throttle opening sensor failure due to the voltage drop of the power supply of the throttle signal. Therefore, in all cases where the throttle pulse signal based on the throttle signal is not detected, it is possible to reduce the erroneous determination of the failure and the false warning to the driver as compared with the conventional device that has determined that the throttle opening sensor failure. Therefore, the accuracy of the throttle opening sensor failure diagnosis can be improved.
[0016]
In the invention according to claim 2, the throttle opening sensor failure diagnosing means does not detect the throttle pulse signal based on the throttle signal output from the engine control unit by the throttle opening sensor abnormality determining means, and detects the power supply voltage value. If the voltage value of the power source of the throttle signal detected by the means is greater than or equal to a preset value, it is determined that a failure has occurred in the throttle opening sensor. On the other hand, when the voltage value of the power supply of the throttle signal is less than the set value, it is not determined that a failure has occurred in the throttle opening sensor.
[0017]
Therefore, in a vehicle configured to control the automatic transmission based on the throttle pulse signal obtained via the engine control unit, the engine control unit stops before the throttle opening sensor failure diagnosis means when the ignition key is turned off. This makes it possible to prevent erroneous determination of a throttle opening sensor failure due to the occurrence of the failure.
[0018]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, embodiments of the present invention will be described based on examples.
[0019]
First, the configuration will be described.
FIG. 1 is a block diagram showing the overall configuration of the first embodiment.
First, the configuration will be described. 1 is an engine, 2 is an automatic transmission, 3 is a transmission output shaft, 4 is a control valve unit, 5 is an ECU, and 6 is an ATCU. The control valve unit 4 performs shift control based on a control signal from the ATCU 6.
[0020]
As sensors for detecting the state of the engine 1, an idle switch 11 for detecting whether the engine is idling, a full throttle switch 12 for detecting whether the accelerator opening is fully opened, and a throttle opening sensor for detecting the throttle opening 13 and an engine speed sensor 14 for detecting the engine speed.
[0021]
As sensors for detecting the state of the automatic transmission 2, an inhibitor switch 15 for outputting a range signal selected by the driver, a temperature sensor 16 for detecting the oil temperature in the automatic transmission 2, and the rotational speed of the transmission output shaft 3 are used. A vehicle speed sensor 17 for detecting the vehicle speed and an ignition voltage sensor 18 are provided.
[0022]
The ECU 5 receives sensor signals from the idle switch 11, the full throttle switch 12, the throttle opening sensor 13, and the engine speed sensor 14. The ECU 5 controls the engine 1 based on these signals. Further, the throttle signal that is the detection value of the throttle opening sensor 13 input to the ECU 5 is converted into a pulse signal by the ECU 5 and output to the ATCU 6.
[0023]
The ATCU 6 receives each sensor signal from the inhibitor switch 15, the humidity sensor 16, the vehicle speed sensor 17, and the ignition voltage sensor 18 and a pulse signal from the ECU 5. The ATCU 6 outputs a shift command to the control valve unit 4 based on these signals.
[0024]
Also, the ATCU 6 determines the Hi level and Low level of the voltage value of the throttle pulse signal based on the throttle signal output from the ECU 5, measures the Hi level time and Low level time of the pulse by the input processing logic, and opens the throttle. Recognize the degree.
[0025]
The ignition voltage sensor 18 detects the voltage value of the ignition power supply and outputs it to the ATCU 6.
[0026]
Next, the operation will be described.
[Throttle opening sensor failure diagnosis process]
FIG. 2 is a flowchart showing a failure diagnosis process of the throttle opening sensor 13 in the ATCU 6, and this control is performed when the ATCU 6 stops detecting the voltage value of the throttle pulse signal output from the ECU 5.
[0027]
In step 101, the fail safe execution flag FSflag, the warning flag Wflag, and the time t are initialized.
[0028]
In step 102, it is detected by a predetermined logic whether the throttle opening sensor 13 is disconnected or the power supply is short-circuited. If the throttle opening sensor 13 is disconnected or the power supply is short-circuited, step 102 is performed. If the throttle opening sensor 13 is not disconnected and the power supply is not short-circuited, the process proceeds to step 103.
[0029]
In step 103, it is determined by a predetermined logic whether the throttle opening sensor 13 is short-circuited to GND (ground). If the short-circuit is short-circuited, the process proceeds to step 104. If the short-circuit is not short-circuited, this control is terminated. To do.
[0030]
In step 104, the time t is counted up.
[0031]
In step 105, it is determined whether or not a predetermined time has elapsed since the ATCU 6 no longer detects a voltage. If the predetermined time has elapsed, the process proceeds to step 106, and if the predetermined time has not elapsed, the process proceeds to step 102. Return.
[0032]
In step 106, a fail safe execution flag FSflag = 1 is set. Thereby, control which operates automatic transmission 2 to the safe side is performed.
[0033]
In step 107, the voltage value V of the ignition power supply the ignition voltage sensor 18 detects detects whether a preset value greater than or equal _to V _0, when the set value greater than or equal _to V _0, the process proceeds to step 108, setting value it is less than V ₀ is the control is terminated.
[0034]
In step 108, the warning flag Wflag = 1 is set, the warning lamp is turned on, and a warning is displayed to the driver.
[0035]
In step 109, a command for storing the fault code is output, the fault code is recorded in the nonvolatile memory, and this control is terminated.
[0036]
From the above steps 101 and 102, when it is determined that the throttle opening sensor 13 is not disconnected or the power supply is short-circuited, and it is further determined that the GND opening is not short-circuited, it is determined that the throttle opening sensor 13 is not malfunctioning, This control is terminated.
[0037]
On the other hand, if it is determined in steps 101 and 102 that the throttle opening sensor 13 is disconnected or the power supply is short-circuited, or if it is determined that the GND is short-circuited, the routine proceeds to step 104, and after a predetermined time has elapsed, Then, the fail safe execution flag FSflag is set to perform control for operating the automatic transmission 2 to the safe side.
[0038]
Next, when the voltage value V of the ignition power source detected by the ATCU 6 is greater than or equal to the set value V ₀ in step 107, it is determined that the throttle opening sensor 13 is out of order, and the driver is determined in steps 108 and 109. Warning display and fault code recording in the non-volatile memory are performed. On the other hand, if the voltage value V of the ignition power source detected by the ATCU 6 is less than the set value V ₀ in step 107, it is not determined that the throttle opening sensor 13 is malfunctioning, and no warning display and malfunction code recording are performed. This control ends.
[0039]
[When ignition key is off]
FIG. 3 is a time chart showing the control of the ECU 5 and the ATCU 6 according to Embodiment 1 when the ignition key is turned off.
[0040]
At t1, the power supplied to the ECU 5 and the ATCU 6 is shut off by turning off the ignition key, and accordingly, the voltage value V of the ignition power starts to decrease.
[0041]
At t2, the CPU reset of the ECU 5 occurs, and the output of the throttle pulse based on the throttle signal from the ECU 5 to the ATCU 6 stops. At the same time, the ATCU 6 does not detect the throttle pulse, and starts failure diagnosis control of the throttle opening sensor 13 based on the above-described flowchart.
[0042]
In FIG. 2, after the fail safe execution flag, the warning flag, and the time t are initialized in step 101, it is determined in step 102 that the throttle opening sensor 13 is not disconnected or the power supply is short-circuited. It is determined that there are 13 GND shorts, and the time t is counted up in step 104. Subsequently, Step 102 to Step 105 are repeated until the time t reaches a predetermined time in Step 105.
[0043]
At t3, since a predetermined time has elapsed, the fail safe flag is set in step 106, and the voltage value V of the ignition power source is compared with the set value V ₀ in step 107. At this time, it is determined not to be the failure of the throttle opening sensor 13 from V <V ₀ failure diagnosis control of the throttle opening sensor 13 is completed.
[0044]
At t4, the CPU reset of ATCU6 occurs.
[0045]
As described above, in the automatic transmission failure diagnosis apparatus according to the first embodiment, the ignition voltage sensor 18 detects the ignition voltage V when the ATCU 6 stops detecting the throttle pulse signal. When the ignition voltage V is equal to or higher than the set value V ₀ , it is determined that the throttle opening sensor 13 has failed, and a driver warning and a failure code are stored. On the other hand, when the ignition voltage V is less than the set value V ₀ , it is not determined that the throttle opening sensor 13 has failed, and the driver warning and failure code storage are not performed. Therefore, it is possible to prevent erroneous determination of failure of the throttle opening sensor 13 due to voltage drop of the ignition power source or ignition key-off, and to improve the accuracy of failure diagnosis of the throttle opening sensor 13.
[0046]
Further, when the ATCU 6 no longer detects the throttle pulse signal, even if the throttle opening sensor 13 is not determined to be out of order, the fail safe flag is set and the automatic transmission 2 has an abnormality in the throttle opening sensor 13. Output generation signal. That is, even if the voltage value V of the ignition power source is less than the set value V ₀ and the throttle opening sensor 13 is not determined to be faulty, there may be a case where an abnormality has actually occurred in the throttle opening sensor 13. It is done. Even in this case, by outputting an abnormality occurrence signal to the automatic transmission 2, it is possible to operate the automatic transmission 2 on the safe side and avoid damage to the automatic transmission or accidents.
[0047]
(Other examples)
As mentioned above, although the failure diagnosis apparatus of the automatic transmission of the present invention has been described based on the embodiment, the specific configuration is not limited to this embodiment, and each claim of the claims Design changes and additions are allowed without departing from the spirit of the invention described.
[0048]
For example, in the present embodiment, a throttle signal that is an output value of the throttle opening sensor 13 is input to the ECU 5 and then converted into a throttle pulse signal corresponding to the throttle signal by the ECU 5 and then input to the ATCU 6. As shown in the example, the present invention can also be applied to a vehicle having a configuration in which a throttle signal is directly input from the throttle opening sensor 13 to the ATCU 6.
[Brief description of the drawings]
FIG. 1 is a block diagram illustrating an overall configuration of a first embodiment.
FIG. 2 is a flowchart showing a throttle sensor failure diagnosis control according to the first embodiment.
FIG. 3 is a time chart showing control at the time of key-off of the ECU and ATCU according to the first embodiment.
FIG. 4 is a circuit configuration diagram relating to throttle signals of an ECU and an ATCU.
FIG. 5 is an explanatory diagram showing a pulse signal based on a throttle signal output from an ECU.
FIG. 6 is a time chart showing control during key-off of a conventional ECU and ATCU.
[Explanation of symbols]
1 Engine 2 Automatic transmission 3 Transmission output shaft 4 Control valve unit 5 ECU (Engine control unit)
6 ATCU (AT Control Unit)
11 Idle switch 12 Full throttle switch 13 Throttle opening sensor 14 Engine speed sensor 15 Inhibitor switch 16 Temperature sensor 17 Vehicle speed sensor 18 Ignition voltage sensor

Claims (2)

In an automatic transmission that performs shift control based on a throttle signal that is a detection value of a throttle opening sensor,
Throttle opening sensor abnormality determining means for detecting a throttle pulse signal based on the throttle signal and determining abnormality of the throttle opening sensor;
Power supply voltage value detection means for detecting the voltage value of the power supply of the throttle signal;
When the throttle opening sensor abnormality determination means does not detect a throttle pulse signal based on the throttle signal, and the power supply voltage value of the throttle signal detected by the power supply voltage value detection means is greater than or equal to a preset set value In addition, a throttle opening sensor failure diagnosis means for determining that the throttle opening sensor has failed,
A fault diagnosis apparatus for an automatic transmission, comprising: In the automatic transmission failure diagnosis device according to claim 1,
The throttle opening sensor outputs a throttle signal to the engine control unit,
The engine control unit outputs a throttle pulse signal based on the throttle signal to the throttle opening sensor abnormality determining means,
The throttle opening sensor abnormality determining means detects the throttle opening signal abnormality by detecting the throttle pulse signal, and is an automatic transmission failure diagnosis device.

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