JPH11315914A - Failure diagnostic device for automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To appropriately carry out neutral control so as to prevent deterioration of fuel consumption by judging whether a neutral control signal is in a normal condition or not on the basis of a vehicle speed signal, a range signal of an automatic transmission, and the neutral control signal, and diagnosing a failure of a neutral control condition judging unit. SOLUTION: A vehicle speed signal is inputted from a vehicle speed sensor 16 arranged on an automatic transmission 4 into an engine control unit 10, and a neutral control signal PNC1 is inputted from a transmission control unit 12. A D range signal is inputted from a D range switch 14 into the transmission control unit 12, and a neutral control condition judging unit 26 is arranged. A failure diagnosis logic unit 30 is arranged in the engine control unit 10, a vehicle speed signal from the vehicle speed sensor 16, a range signal of the automatic transmission 4, and the neutral control signal PNC1 are inputted into the failure diagnosis logic unit 30, and it is logically judged whether the neutral control signal PNC1 is in a normal condition or not. It is thus possible to diagnose the failure of a neutral control condition judging unit 26 of the transmission control unit 12.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnosis device for an automatic transmission, and more particularly to a failure diagnosis device for a neutral control condition determination unit of a transmission control unit, which can perform failure diagnosis by software.
The neutral control can be executed properly, the fuel efficiency can be reliably improved by suppressing the creep phenomenon, the failure of the neutral control condition judgment unit can be repaired appropriately, and the fuel efficiency can be improved by executing the appropriate neutral control. Can be
In addition, when normal operation is restored from a temporary abnormality or when normal operation is restored by repair, the execution of the neutral control can be allowed, the unnecessary stoppage of the neutral control can be avoided, and the deterioration of fuel efficiency can be prevented. The present invention relates to a failure diagnosis device for an automatic transmission.

[0002]

2. Description of the Related Art Some internal combustion engines mounted on vehicles are connected to an automatic transmission having a torque converter and an auxiliary transmission mechanism. Recent vehicles are provided with an engine control unit for controlling an internal combustion engine, and a transmission control for controlling an automatic transmission.

An automatic transmission having a torque converter connected to such an internal combustion engine is a clutch that transmits driving force to an auxiliary transmission mechanism when a forward drive range (for example, a D range) is selected. And an engagement mechanism such as a brake is engaged. When the automatic transmission is selected for the forward running range, even when the vehicle is stopped and the throttle valve is closed, the driving force is transmitted from the torque converter to the auxiliary transmission mechanism, and a creep phenomenon occurs.

The creep phenomenon at the time of stopping the vehicle has a disadvantage that the load on the internal combustion engine is increased to deteriorate the fuel efficiency, and vibration is generated due to the increased load on the internal combustion engine in an idle ring state. Therefore, some automatic transmissions are provided with a transmission control unit that executes neutral control in order to suppress the creep phenomenon when the vehicle is stopped in the forward traveling range.

[0005] Such neutral control of the automatic transmission is executed as shown in FIGS. This automatic transmission is controlled by a transmission control unit. The internal combustion engine to which the automatic transmission is connected is controlled by an engine control unit.

As shown in FIG. 8, a transmission control unit receives a range signal, a throttle opening signal, a brake switch signal, a vehicle speed signal, and a transmission oil (ATF) temperature signal, and performs a neutral control condition determination by a neutral control condition determination unit. Determine the conditions.

The transmission control unit turns on a D range signal, which is a range signal, by a neutral control condition determination unit.
When it is determined that the neutral control condition is satisfied because the throttle opening is fully closed, the brake switch is on, the vehicle speed is zero, and the transmission oil temperature exceeds the set temperature t ° C., the torque converter of the automatic transmission is used. The neutral control is executed so as to cut off the transmission of the driving force to the auxiliary transmission mechanism, and a neutral control signal indicating the execution state of the neutral control is output to the PNC1 engine control unit.

As shown in FIG. 7, when the neutral control condition determination unit starts determining the neutral control condition as shown in FIG. 7 (step 200), the transmission control unit determines whether the D range signal is on (step 200). 202),
It is determined whether or not the throttle opening is fully closed (step 204), and it is determined whether or not the brake switch is on (the brake pedal is depressed) (step 20).
6) It is determined whether or not the vehicle speed is zero (0 km / h) (step 206), and it is determined whether or not the transmission oil temperature exceeds the set temperature t ° C. (step 210).

If all of the above judgments (step 202) to judgment (step 210) are YES, the engagement mechanism of the auxiliary transmission mechanism is released to execute the neutral control of the automatic transmission (step 212), and the neutral control is executed. Is output to the engine control unit (step 214), and the process returns (step 216).

When the D range signal is off and the determination (step 202) is NO, the parking range (P
Range) or the neutral range (N range), the engagement mechanism of the auxiliary transmission mechanism is released to execute the neutral control of the automatic transmission (step 212), and the ON of the neutral control signal PNC1 is controlled by the engine. Output to the section (step 214) and return (step 216).

On the other hand, if the judgments (step 204) to judgment (step 210) are NO, execution of the neutral control of the automatic transmission is stopped (step 21).
8) The neutral control signal PNC1 indicating that the neutral control has been canceled is output to the engine control unit (step 220), and the process returns (step 21).
6).

Thus, the transmission control unit suppresses the creep phenomenon when the automatic transmission is selected to the D range and stops, thereby improving fuel efficiency and preventing vibration.

A control device for such an automatic transmission is disclosed in Japanese Patent Application Laid-Open No. Hei 7-113466. What is disclosed in this publication is a regulator valve that outputs a hydraulic pressure according to a throttle opening, a manual valve that supplies a hydraulic servo of an input clutch by switching the hydraulic pressure output by the regulator valve to a forward range,
A control device for an automatic transmission, comprising: a control valve interposed in an oil passage connecting the manual valve and a hydraulic servo to regulate a hydraulic pressure supplied from the manual valve to prevent creep in a vehicle stopped state. By providing a bypass oil passage that bypasses the control valve and connects the manual valve and the hydraulic servo, and by providing an opening / closing unit that communicates with the bypass oil passage in response to a rise in oil pressure in the bypass oil passage, Even if a failure occurs in the control valve, the input clutch is engaged to enable forward traveling.

[0014]

By the way, in a conventional automatic transmission, when a neutral control condition is satisfied by a neutral control condition determination section of a transmission control section, a torque converter of the automatic transmission is converted to an auxiliary transmission mechanism. The neutral control is executed so as to interrupt the transmission of the driving force to the engine control unit, and a neutral control signal indicating an execution state of the neutral control is output to the engine control unit.

However, since the neutral control condition judging section for judging the neutral control condition is provided on the transmission control section side, the failure of the circuit of the neutral control condition judging section due to disconnection or short circuit is detected by the engine control section. There is a problem that cannot be detected by hardware.

For this reason, even when the neutral control signal is abnormal due to the failure of the neutral control condition determination unit, the engine control unit cannot stop the transmission control unit from executing the neutral control. There is a disadvantage that the execution of the neutral control cannot reliably improve the fuel economy by suppressing the creep phenomenon.

[0017]

SUMMARY OF THE INVENTION Therefore, in order to eliminate the above-mentioned disadvantages, the present invention provides an engine control unit for controlling an internal combustion engine mounted on a vehicle, and provides an automatic transmission connected to the internal combustion engine. A transmission control unit for controlling the transmission, wherein the transmission of the driving force from the torque converter of the automatic transmission to the auxiliary transmission mechanism is interrupted when the neutral control condition is satisfied by the neutral control condition determination unit of the transmission control unit. A failure diagnosis device for an automatic transmission that executes a neutral control and outputs a neutral control signal indicating an execution state of the neutral control to the engine control unit, wherein the vehicle speed signal, the range signal of the automatic transmission, and the neutral Control signals are input, and whether the neutral control signal is normal or abnormal is discussed based on the state of these signals. To determine, characterized in that the fault diagnosis logic unit for diagnosing a failure of the neutral control condition determining unit as a result of the logical judgment provided in the engine control unit.

The engine control unit stores an abnormality code and outputs a stop signal to the transmission control unit to stop the execution of the neutral control when the failure diagnosis logic unit determines that there is an abnormality. In addition, when the failure diagnosis logic unit determines that the abnormality is normal after the failure diagnosis logic unit determines that the transmission is abnormal, the transmission control unit erases the stored abnormality code and allows execution of the neutral control that has been stopped. The engine control unit outputs an allowable signal to the unit.

[0019]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS A failure diagnosis device for an automatic transmission according to the present invention uses a failure diagnosis logic unit provided in an engine control unit.
The vehicle speed signal of the vehicle, the range signal of the automatic transmission, and the neutral control signal are input, and it is logically determined whether the neutral control signal is normal or abnormal based on the state of these signals. By diagnosing the failure of the neutral control condition determination unit based on the result, the engine control unit uses the vehicle speed signal and the range signal monitored by the transmission control unit so that there is no abnormality in hardware. The failure of the determination unit can be diagnosed.

When the failure diagnosis logic unit determines that an abnormality has occurred, the engine control unit stores an abnormality code and outputs a stop signal to the transmission control unit to stop the execution of the neutral control, thereby enabling automatic transmission. At the time of maintenance of the machine, it is possible to notify that the neutral control condition determination unit is out of order by the abnormality code, and to avoid inappropriate execution of the neutral control by the transmission control unit.

When the failure diagnosis logic unit determines that the engine is normal after determining that the transmission is abnormal, the engine control unit erases the stored abnormality code and permits execution of the neutral control that has been stopped. By outputting the permission signal to the section, the neutral control can be immediately executed when the operation returns to the normal state.

[0022]

Embodiments of the present invention will be described below with reference to the drawings. 1 to 6 show an embodiment of the present invention. 6, reference numeral 2 denotes an internal combustion engine mounted on a vehicle (not shown), and reference numeral 4 denotes an automatic transmission. This automatic transmission 4
Includes a torque converter 6 and an auxiliary transmission mechanism 8.

The internal combustion engine 2 is controlled by an engine control unit 10 in ignition timing, fuel supply amount, and the like. The engagement state of the auxiliary transmission mechanism 8 of the automatic transmission 4 is controlled by a transmission control unit 12.

The engine control unit 10 receives a D range signal from a D range switch 14 provided in the auxiliary transmission mechanism 8 of the automatic transmission 4 and receives a vehicle speed signal from a vehicle speed sensor 16 provided in the automatic transmission 4. Then, a neutral control signal PNC1 is input from the transmission control unit 12.

The transmission control unit 12 receives a D range signal from the D range switch 14,
A throttle opening signal is inputted from a throttle opening sensor 18 provided on a throttle valve (not shown) of the vehicle, a brake switch signal is inputted from a brake switch 22 provided on a brake pedal 20 of the vehicle, and a vehicle speed is outputted from the vehicle speed sensor 16. A signal is input, and a transmission oil (ATF) temperature signal is input from an oil temperature sensor 24 provided in the automatic transmission 4.

The transmission control section 12 is provided with a neutral control condition determination section 26. When the neutral control condition is satisfied by the neutral control condition determination unit 26 as shown in FIGS. 7 and 8, the transmission control unit 12 transmits the driving force from the torque converter 6 of the automatic transmission 4 to the auxiliary transmission mechanism 8. And a neutral control signal PNC1 indicating the execution state of the neutral control is output to the engine control unit 10.

The failure diagnosis device 28 of the automatic transmission 4
A failure diagnosis logic unit 30 is provided in the engine control unit 10. The failure diagnosis logic unit 30 receives the vehicle speed signal of the vehicle, the range signal of the automatic transmission 4, and the neutral control signal PNC1, and outputs the neutral control signal PN according to the state of these signals.
It is logically determined whether C1 is normal or abnormal, and a failure of the neutral control condition determination unit 26 of the transmission control unit 12 is diagnosed based on the result of this logical determination.

The engine control unit 10 includes a failure diagnosis logic unit 3
When it is determined that 0 is abnormal, an abnormal code is stored (N
A stop signal is output to the transmission control unit 12 to stop the execution of the neutral control together with the (G flag = on).

The engine control unit 10 determines whether the failure diagnosis logic unit 30 is normal after the failure diagnosis logic unit 30 determines that it is abnormal.
An allowance signal is output to the transmission control unit 12 to erase the stored abnormality code (NG flag = OFF) and allow execution of the neutral control that has been stopped.

Next, the operation will be described with reference to FIGS.

The failure diagnosis device 28 of the automatic transmission 4 is shown in FIG.
As shown in (1), when the failure diagnosis is started by the failure diagnosis logic unit 30 (step 100), it is determined whether the neutral control signal PNC1 is on (step 102).

If the judgment (step 102) is YES, judgment A shown in FIG. 2 is made (step 104). In this determination (step 104), it is determined whether or not the D range signal, which is the range signal, is on, the vehicle speed exceeds zero (0 km / h), and the neutral control signal PNC1 is on.

D-range signal is on, vehicle speed is zero (0 km / h)
, The neutral control signal P
The ON state indicating that the NC1 is performing the neutral control is an abnormality due to a short circuit of the neutral control condition determination unit 26.

Therefore, the determination (step 104) is Y
In the case of ES, ON of the NG flag, which is an abnormality code, is stored in a memory (not shown) of the engine control unit 10 (step 106), and a stop signal is sent to the transmission control unit 12 to stop the execution of the neutral control. Output (Step 10
8) Return (step 110).

On the other hand, if the judgment (step 104) is NO
In the case of, it is determined whether or not the NG flag, which is an abnormal code, is on (step 112).

If the determination (step 112) is NO, the process jumps to the return (step 110). If this determination (step 112) is YES, determination C shown in FIG. 4 is performed (step 114). In this determination (step 114), it is determined whether the D range signal, which is the range signal, is off and the neutral control signal PNC1 is on.

When the D range signal is off, that is, in the P range or the N range, the neutral control signal PNC1 is executed by releasing the engagement mechanism of the auxiliary transmission mechanism 8 and executing the neutral control. Since it is turned on to indicate that the vehicle is in the middle, the neutral control condition determination unit 26 is normal.

Therefore, the determination (step 114) is
In the case of ES, the NG flag, which is an abnormal code, is reset to off (step 116), an allowance signal is output to the transmission control unit 12 to allow the execution of the neutral control, and the process returns (step 110). On the other hand, if the determination (step 114) is NO, a stop signal is output to the transmission control unit 12 to stop the execution of the neutral control (step 108), and the process returns (step 1).
10).

If the determination (step 102) is NO
In the case of, the judgment B shown in FIG.
8). In this determination (step 118), it is determined whether or not the D range signal, which is the range signal, is off and the neutral control signal PNC1 is off.

Although the D range signal is off, that is, the P range or the N range, and the neutral control is executed, the neutral control signal PNC1 is maintained even though the engagement mechanism of the auxiliary transmission mechanism 8 is released to execute the neutral control. Is turned off, indicating that the execution of is not performed, is an abnormality due to disconnection of the circuit of the neutral control condition determination unit 26.

Therefore, the determination (step 118) is Y
In the case of ES, ON of the NG flag, which is an abnormality code, is stored in a memory (not shown) of the engine control unit 10 (step 106), and a stop signal is sent to the transmission control unit 12 to stop the execution of the neutral control. Output (Step 10
8) Return (step 110).

On the other hand, if the judgment (step 118) is NO
In the case of, it is determined whether or not the NG flag, which is an abnormal code, is on (step 120).

If the determination (step 120) is NO, the process jumps to the return (step 110). If this determination (step 120) is YES, a determination D shown in FIG. 5 is performed (step 122). In this determination (step 122), it is determined whether or not the D range signal, which is the range signal, is on, the vehicle speed exceeds zero (0 km / h), and the neutral control signal PNC1 is off.

When the D range signal is on and the vehicle speed is zero (0 km /
If h) is exceeded, the neutral control signal PNC1 stops executing the neutral control because the execution of the neutral control is stopped so that the engagement mechanism of the auxiliary transmission mechanism 8 is engaged to transmit the driving force. Since the signal is turned off indicating that the operation is stopped, the neutral control condition determination unit 26 is normal.

Therefore, the judgment (step 122) is Y
In the case of ES, the NG flag, which is an abnormal code, is reset to off (step 124), an allowance signal is output to the transmission control unit 12 to allow the execution of the neutral control, and the process returns (step 110). On the other hand, if the determination (step 122) is NO, a stop signal is output to the transmission control unit 12 to stop the execution of the neutral control (step 108), and the process returns (step 1).
10).

As described above, the failure diagnosis device 28 of the automatic transmission 4 includes the failure diagnosis logic unit 3 provided in the engine control unit 10.
If 0, the vehicle speed signal of the vehicle, the D range signal of the automatic transmission 4 and the neutral control signal PNC1 are inputted, and it is logically determined whether the neutral control signal PNC1 is normal or abnormal based on the state of these signals. The failure of the neutral control condition determination unit 26 is diagnosed based on the result of the logical determination.

The failure diagnosis logic unit 30 determines whether the neutral control signal PNC1 is normal or abnormal using the vehicle speed signal of the vehicle and the D range signal of the automatic transmission 4. The vehicle speed sensor 16 for detecting the vehicle speed signal and the D range switch 14 for detecting the D range signal are monitored by the transmission control unit 12 so that there is no abnormality.

Therefore, if the judgment (step 104) and the judgment (step 118) are determined to be abnormal based on the normal vehicle speed signal and the D range signal, the disconnection or short-circuit abnormality occurs in the neutral control condition determination section 26. Thus, it can be determined that the neutral control signal PNC1 is abnormal.

If it is determined that the determination (step 104) and the determination (step 118) are abnormal, respectively, in the process (step 106), the NG flag, which is an abnormal code, is turned on by a memory (not shown) of the engine control unit 10. And a stop signal is output to the transmission control unit 12 to stop the execution of the neutral control in the process (step 108).

If the judgment of the abnormality (Step 104) and the judgment (Step 118) are temporary and the normal state is restored, or if the normal state is restored by repair, the judgment (Step 112) and the judgment are made. After it is determined in step (120) that the NG flag, which is an abnormal code, is ON, the neutral control signal P is determined in determination (step 114) and determination (step 122).
When NC1 is determined to be normal, the NG flag, which is an abnormal code, is reset to OFF, and the neutral control by the transmission control unit 12 is allowed.

Thus, the failure diagnosis device 28 uses the vehicle speed signal of the vehicle speed sensor 16 and the D range signal of the D range switch 14 which are monitored by the transmission control unit 12 so that there is no abnormality in hardware. And the engine control unit 10
The failure diagnosis logic unit 30 can diagnose the failure of the neutral control condition determination unit 26.

Therefore, the failure diagnosis device 28 can diagnose the failure of the neutral control condition determination unit 26 of the transmission control unit 12 by software, can appropriately execute the neutral control, and can reduce the creep phenomenon. It is possible to surely achieve an improvement in fuel efficiency by suppression.

The engine control unit 10 includes a failure diagnosis logic unit 3
When it is determined that 0 is abnormal, maintenance of the automatic transmission 4 is performed by storing the ON of the NG flag, which is an abnormal code, and outputting a stop signal to the transmission control unit 12 to stop the execution of the neutral control. At this time, it is possible to notify that the neutral control condition determination unit 26 is out of order by turning on the NG flag, which is an abnormal code, and to avoid inappropriate execution of the neutral control by the transmission control unit 12.

Therefore, the failure diagnosis device 28 can appropriately repair the failure of the neutral control condition determination section 26, and can suppress the creep phenomenon by executing the appropriate neutral control to improve the fuel efficiency.

Further, when the engine control unit 10 determines that the failure diagnosis logic unit 30 is normal after determining that it is abnormal,
By outputting an allowance signal to the transmission control unit 12 so as to allow the stored NG code, which is the stored abnormal code, to be turned off and to allow the execution of the neutral control that has been stopped, the neutral control is immediately executed when the transmission returns to the normal state Can be done.

Therefore, the failure diagnosis device 28 can allow the execution of the neutral control when the normal condition is restored from the temporary abnormality or when the normal condition is restored by the repair, and the suspension of the neutral control is unnecessarily continued. Can avoid
Fuel economy can be prevented from deteriorating.

[0057]

As described above, the failure diagnosis device for an automatic transmission according to the present invention utilizes the vehicle speed signal and the range signal which are monitored by the transmission control unit so that there are no abnormalities in hardware. The failure of the neutral control condition determination unit can be diagnosed by the failure diagnosis logic unit of the control unit.

For this reason, the failure diagnosis apparatus can diagnose the failure of the neutral control condition determination section of the transmission control section by software, can appropriately execute the neutral control, and can reduce the fuel consumption by suppressing the creep phenomenon. Can surely be improved.

The engine control unit is capable of notifying that the neutral control condition determination unit is out of order by an abnormality code during maintenance and inspection of the automatic transmission, and executing inappropriate neutral control by the transmission control unit. Can be avoided. Therefore, this failure diagnosis device
The failure of the neutral control condition determination unit can be appropriately repaired, and the creep phenomenon can be suppressed and the fuel efficiency can be improved by executing the appropriate neutral control.

Further, the engine control section can immediately execute the neutral control when the engine returns to the normal state. For this reason, this failure diagnosis device can allow the execution of the neutral control when the normal condition is restored from the temporary abnormality or when the device is restored to the normal condition due to the repair, and it is possible to avoid the unnecessary continuation of the suspension of the neutral control. As a result, deterioration of fuel efficiency can be prevented.

[Brief description of the drawings]

FIG. 1 is a flowchart of a failure diagnosis of a failure diagnosis device according to an embodiment of the present invention.

FIG. 2 is a logic diagram of abnormality determination when a D range signal is on.

FIG. 3 is a logic diagram of abnormality determination when a D range signal is off.

FIG. 4 is a logic diagram of a normal judgment when a D range signal is off.

FIG. 5 is a logic diagram of a normal judgment when the D range signal is on.

FIG. 6 is a schematic configuration diagram of a failure diagnosis device for an automatic transmission.

FIG. 7 is a flowchart of a neutral control condition determination.

FIG. 8 is a logic diagram of a neutral control condition determination.

[Explanation of symbols]

 Reference Signs List 2 internal combustion engine 4 automatic transmission 6 torque converter 8 auxiliary transmission mechanism 10 engine control unit 12 transmission control unit 26 neutral control condition determination unit 28 failure diagnosis device 30 failure diagnosis logic unit

──────────────────────────────────────────────────続 き Continued on front page (51) Int.Cl. ⁶ Identification code FI F16H 59:72

Claims (3)

[Claims] An engine control unit for controlling an internal combustion engine mounted on a vehicle is provided, a transmission control unit for controlling an automatic transmission connected to the internal combustion engine is provided, and a neutral control condition determination of the transmission control unit is provided. When the neutral control condition is satisfied by the unit, the neutral control is executed so as to cut off the transmission of the driving force from the torque converter of the automatic transmission to the auxiliary transmission mechanism, and the neutral control signal indicating the execution state of the neutral control is transmitted. In the failure diagnosis device for an automatic transmission that outputs to an engine control unit, a vehicle speed signal of the vehicle, a range signal of the automatic transmission, and the neutral control signal are input, and depending on the state of these signals, the neutral control signal is normal. It is logically determined whether or not the neutral control condition exists, and the neutral control condition is determined based on the result of the logical determination. A failure diagnosis device for an automatic transmission, wherein a failure diagnosis logic unit for diagnosing a failure in a determination unit is provided in the engine control unit. 2. The engine control unit stores an abnormality code and outputs a stop signal to the transmission control unit to stop the execution of the neutral control when the failure diagnosis logic unit determines that the abnormality is abnormal. The failure diagnosis device for an automatic transmission according to claim 1, wherein the failure diagnosis device is a control unit. 3. The engine control unit according to claim 1, wherein when the failure diagnosis logic unit determines that the abnormality is normal after the abnormality diagnosis unit determines that the transmission is abnormal, the engine control unit erases the stored abnormal code and permits execution of the neutral control that has been stopped. The failure diagnosis device for an automatic transmission according to claim 1, wherein the failure diagnosis device is an engine control unit that outputs an allowable signal to the machine control unit.