JPH09329221A - Failure judging device of oil temperature detecting means in automatic transmission - Google Patents

Abstract

PROBLEM TO BE SOLVED: To improve failure judging accuracy for judging a failure of an oil temperature detecting means by arranging a means for suppressing failure judgment comparing with the time of a running condition having a large slip page at the time of a running condition having a small slippage between the pump of the torque converter of an automatic transmission and a turbine. SOLUTION: A minimum oil temperature Tmin and a maximum oil temperature Tmax are renewed as necessary in S53. A slip s is calculated as a difference between engine rotational speed Ne and a turbine rotational speed N is S54, and an accumulated slip index X is calculated as a value added by a present increasing G (s) on a previous accumulated index X is S56. When the accumulated slip index X exceeds a prescribed value X0, it is judged whether the increasing width (Tmax-Tmin) of an oil temperature is not more than a prescribed value ΔT0 or not in S58. When its judgment is 'No', fail flag FF is reset in S59. When the judgment is 'YES', a failure code showing a failure of an oil temperature sensor is stored in the failure information memory of a RAM in S60.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure determination device for oil temperature detection means of an automatic transmission, and more particularly to a device for making a failure determination difficult when slippage in a torque converter of an automatic transmission is small.

[0002]

2. Description of the Related Art An automatic transmission of a vehicle is provided with a torque converter, a speed change gear mechanism, a plurality of clutch mechanisms for switching the speed change gear mechanism, a brake mechanism, a control valve unit, etc., to change the oil temperature. Then, the viscosity of the oil changes, and the performance and responsiveness of the automatic transmission also change. Therefore, a control valve unit of an automatic transmission is usually provided with an oil temperature sensor for detecting the oil temperature, and the oil temperature detected by the oil temperature sensor is applied to the shift control. Therefore, if the oil temperature sensor fails, the gear change control is hindered. Therefore, various techniques for detecting the failure of the oil temperature sensor have been adopted.

In the torque converter of the automatic transmission, torque is transmitted from the pump to the turbine through the viscosity of oil, but the slip between the pump and the turbine becomes larger in the low speed shift stage and in the low speed shift stage. The oil temperature rise in the torque converter becomes large. Further, at a high speed shift stage, the oil temperature rise in the torque converter is not so large because the slip between the pump and the turbine is small, but the oil temperature rise due to the agitation of oil in the transmission gear mechanism is large.

For example, most commonly, when the oil temperature of the automatic transmission does not substantially rise even after running for a predetermined time at a predetermined vehicle speed of about 25 to 30 km / h or more from the start of running of the vehicle, the oil temperature A failure determination device that determines that the detection means is in failure is employed. In this type of failure determination device, one vehicle speed is set as the predetermined vehicle speed, and one time is set as the predetermined time. On the other hand, Japanese Patent Laid-Open No. 7-301315 discloses that the oil temperature of the automatic transmission should be increased (D range, vehicle speed is 10 km / h or more, throttle opening is 1/8 or more, engine speed is 450 rpm or more). Under all conditions), a failure determination device that determines the cumulative time when the oil temperature becomes an abnormal value and determines that the oil temperature sensor is defective when the cumulative time exceeds a predetermined value is described. .

[0005]

In the conventional general failure determination device, the vehicle speed is set to a low value of about 25 to 30 Km / h, so only low speed running, that is, only an increase in the oil temperature in the torque converter is required. The failure will be determined as the target. However, for example, the vehicle may travel in a coast state below the no-load line (deceleration traveling state or downhill traveling state) immediately after the start of traveling, but in this case, slippage between the pump of the torque converter and the turbine hardly occurs, and Since the increase in the oil temperature is extremely small, it is difficult to determine the failure of the oil temperature sensor, and the accuracy and reliability of the failure determination decrease. Incidentally, the failure determination device described in the above publication, it is necessary to use many parameters for failure determination control, and in order to obtain the cumulative time at which the oil temperature becomes an abnormal value,
Control becomes complicated. An object of the present invention is to improve the accuracy and reliability of failure determination for determining the failure of the oil temperature detecting means through relatively simple control.

[0006]

A failure determination device for an oil temperature detecting means of an automatic transmission according to claim 1 is a failure determining device for determining a failure of an oil temperature detecting means for detecting an oil temperature of an automatic transmission of a vehicle. In, in response to the detection result of the oil temperature detection means, a failure determination means for determining that the oil temperature detection means is a failure when the increase amount of the oil temperature before and after the start of travel is less than or equal to a predetermined value
The failure determination means makes it more difficult to issue a failure determination (determination of a failure) in a traveling state in which slippage between the pump of the torque converter of the automatic transmission and the turbine is small compared to a traveling state in which slippage is large. A failure determination suppressing means is provided.

The failure determining means receives the detection result of the oil temperature detecting means, and determines that the oil temperature detecting means has a failure when the amount of increase in the oil temperature before and after the start of travel is equal to or less than a predetermined determination threshold value. To do. However, when the vehicle is traveling in the coast state immediately after the start of traveling, the increase in the oil temperature is extremely small because the slippage in the torque converter of the automatic transmission hardly occurs, so that the oil temperature detecting means does not operate normally. Even if there is, it may be erroneously determined to be a failure. Therefore,
Since the failure determination means is provided with failure determination suppression means that makes it more difficult to make a failure determination in a running state in which slip between the pump and the turbine of the torque converter of the automatic transmission is small as compared to a running state in which slip is large, It becomes difficult to make a failure determination when the torque converter is in a running state in which slippage is small, and it becomes difficult to make an erroneous determination that a failure has occurred. Therefore, the accuracy and reliability of failure determination can be improved.

According to a second aspect of the present invention, there is provided the failure determination device for the oil temperature detecting means of the automatic transmission according to the first aspect, wherein the running state with small slippage is a coast state in which the engine load is equal to or less than a predetermined value determined according to the vehicle speed. The failure determination suppressing means has a coast determination means for determining the coast state. That is, the coast determination means determines a coast state (a deceleration traveling state or a downhill traveling state) in which the engine load is equal to or less than a predetermined value (that is, less than or equal to the no-road line) determined according to the vehicle speed, and in the coast state, the oil temperature detecting means. It is difficult to make a failure determination that the is a failure.

According to a third aspect of the invention, there is provided the failure determination device for the oil temperature detecting means of the automatic transmission according to the second aspect of the invention, wherein the coast determining means determines when the accumulated idle ON time during traveling is equal to or greater than a set value. It is characterized by determining that it is in a coast state. In this way, since it is determined that the vehicle is in the coast state when the accumulated time of the idle switch ON during traveling is equal to or greater than the set value, it is possible to reliably determine the coast state and ensure the accuracy and reliability of failure determination.

According to a fourth aspect of the present invention, there is provided the failure determination device for the oil temperature detecting means of the automatic transmission according to the second aspect, wherein the coast determining means determines the coast state based on the vehicle speed and the throttle opening. It is a feature. Since the vehicle speed and the throttle opening are set as parameters for the no-road line of the vehicle, the coast state can be reliably determined based on the vehicle speed and the throttle opening.

According to a fifth aspect of the present invention, there is provided the failure determination device for the oil temperature detecting means of the automatic transmission according to the first aspect of the invention, wherein the failure determining means runs at a predetermined vehicle speed or more for a predetermined time or more with respect to the oil temperature before the start of running. It is characterized in that the failure of the oil temperature detecting means is judged based on the increase amount of the oil temperature at that time. If the vehicle travels at a predetermined vehicle speed or higher for a predetermined time or longer, the oil temperature rises due to slippage between the pump and turbine of the torque converter or agitation of oil in the speed change gear mechanism in the normal case other than the coast state. It is possible to determine the failure of the oil temperature detection means based on the rising width of

According to a sixth aspect of the present invention, there is provided the failure determination device for the oil temperature detecting means of the automatic transmission according to the fifth aspect, wherein when the failure determination suppressing means is in a running state with small slippage, it is more than in other running states. Also, the predetermined time is set to be long. Since the oil temperature rising speed in the torque converter is small in the traveling state with small slippage, the accuracy and reliability of the failure determination can be secured by setting the predetermined time longer than in the other traveling states.

According to a seventh aspect of the present invention, there is provided a failure determination device for an oil temperature detecting means of an automatic transmission, comprising:
It is characterized in that the failure determination suppressing means sets the determination threshold value to be smaller in a traveling state with less slippage than in other traveling states. That is, since the oil temperature rising speed in the torque converter is small when the vehicle is running with a small amount of slip, by setting the determination threshold value smaller than when the vehicle is running other than that, the accuracy and reliability of failure determination are ensured. it can.

According to an eighth aspect of the invention, there is provided the failure determination device for the oil temperature detecting means of the automatic transmission according to the first aspect of the invention, wherein the failure determination suppressing means prohibits the failure determination when the vehicle is running with a small amount of slippage. It is what When the vehicle is running with a small amount of slip, the speed of oil temperature rise in the torque converter is small, so that an erroneous determination is likely to occur.

According to a ninth aspect of the present invention, there is provided the failure determination device for the oil temperature detecting means of the automatic transmission, which is provided with notifying means for notifying the driver of the failure of the oil temperature detecting means. It is a thing. This informing means informs the driver of the failure of the oil temperature detecting means, so that it is possible to take measures such as repairing the oil temperature detecting means.

According to a tenth aspect of the invention, there is provided the failure determination device for the oil temperature detecting means of the automatic transmission according to the first aspect of the invention, further comprising storage means for storing information on the failure of the oil temperature detecting means. It is a thing. Therefore, the information on the failure can be utilized for displaying the failure of the oil temperature detecting means, or applied for adjusting the shift control. In the invention of claim 1, the failure determination device of the oil temperature detecting means of the automatic transmission according to claim 11 is characterized in that the start of running is the start of running following ON of the ignition switch of the engine. . If the engine is warmed up and starts running, the oil temperature is too high to accurately detect the increase in oil temperature before and after the start of running, but when the running starts following the ignition switch ON of the engine. In addition, the increase amount of the oil temperature can be accurately detected, and the accuracy and reliability of the failure determination can be improved.

[0017]

BEST MODE FOR CARRYING OUT THE INVENTION Embodiments of the present invention will be described below with reference to the drawings. The present embodiment is an example in which the present invention is applied to a failure determination device that determines a failure of an oil temperature sensor (oil temperature detection means) that detects the oil temperature of oil in an automatic transmission installed in an automobile. As shown in FIG. 1, an automatic transmission 2 with a torque converter is connected to an output shaft of an engine 1, an output shaft of the automatic transmission 2 is connected to a drive shaft of an automobile, and automatic transmission is performed by a driving force of the engine 1. The drive wheels are driven via the machine 2. The control unit 3 controls the automatic transmission 2, and the control unit 3 also serves as a control device of the failure determination device. However, the sensors necessary for the shift control are not shown.

An oil temperature sensor 4 provided in the control valve unit 2a of the automatic transmission 2 for detecting the oil temperature T;
A vehicle speed sensor 5 for detecting the vehicle speed V from the rotational speed of the drive shaft, a throttle opening sensor 6 for detecting the throttle opening TVO of the throttle valve of the engine 1, and an idle switch 7 for detecting the fully closed throttle of the engine 1 are provided. And their detection signals are sent to the control unit 3
Is supplied to In addition, when a failure of the oil temperature sensor 4 is determined, a display 8 including a liquid crystal display for notifying the driver of the failure is provided on the instrument panel of the automobile. The control unit 3 is supplied with power from the battery 9 via the ignition switch 10.

The control unit 3 has an input / output interface, a microcomputer, a display controller for the display 7, a plurality of drive circuits for the control valve of the automatic transmission 2, and the like.
The microcomputer consists of CPU, ROM and RAM
In addition to the control program for gear shift control, the control program for fault determination control according to the present invention is stored in advance in the ROM, and the RAM stores memory for fault determination control in addition to memories for gear shift control. A failure information memory and a plurality of memories are provided for this purpose. However, the RAM is backed up by a secondary battery and retains the stored data even when the ignition switch 10 is turned off.

Next, an outline of this failure determination control will be described. As shown in FIG. 2, when the ignition switch 10 of the automobile is turned on and the engine 1 is started to start traveling, the oil temperature of the oil in the automatic transmission 2 gradually rises.
If the oil temperature sensor 4 is normal, the detected oil temperature T also gradually rises. However, if the oil temperature sensor 4 is out of order, the oil temperature will not change substantially even if time elapses. In this failure determination device, after starting traveling, the vehicle travels at a low speed V1 (for example, 25 km / h) or more for a predetermined time C1 (for example, 150 seconds) or more, and then at a high speed predetermined vehicle speed V2 (for example, 60 km / h). ) When running for a predetermined time C2 (for example, 100 seconds) or more,
When the difference between the maximum value Tmax and the minimum value Tmin of the oil temperature T is less than or equal to a predetermined value, it is determined that the oil temperature sensor 4 is out of order.

During the low speed running, the oil temperature rise in the torque converter of the automatic transmission 2 is larger than the oil temperature rise in the shift gear mechanism, and during the high speed run, the oil temperature rise in the shift gear mechanism. Becomes larger than the oil temperature rise in the torque converter. As described above, in this failure determination device, when the vehicle normally starts traveling, the failure determination is performed after the oil temperature is surely increased through both the oil temperature increase in the torque converter and the oil temperature increase in the transmission gear mechanism.
Further, when the cumulative time in the coast state within the period of the predetermined time C1 becomes equal to or more than the set value, the determination as to whether or not there is a failure is prohibited, and the coast state within the period of the predetermined time C2 (deceleration traveling state or downhill When the cumulative time of the running state) is equal to or greater than the set value, the determination as to whether or not there is a failure is prohibited.

By the way, in the case as shown in FIG. 3, since the vehicle shifts to high-speed traveling immediately after the start of traveling, the predetermined vehicle speed V1
The timekeeping for the above running and the timekeeping for the running at the predetermined vehicle speed V2 or higher are performed in parallel. In this case, when the time for traveling at or above the predetermined vehicle speed V1 has timed out, the timing for traveling at or above the predetermined vehicle speed V2 is reset and restarted. Similarly, when the time for traveling at or above the predetermined vehicle speed V2 has timed out, the time for traveling at or above the predetermined vehicle speed V1 is reset and restarted. This is to ensure the accuracy and reliability of failure determination.

Next, the failure determination control routine will be described with reference to a flowchart. Si (i = 1, 2, 3, ...) In the flowchart indicates each step. Here, the symbols used in the flowchart will be described. Timer TM ... Countdown timer FF ... Fail flag ("0" when oil temperature sensor is normal, "1" when failure) FG1 ... Vehicle speed V ≧ predetermined vehicle speed V1 flag FG2 ... A flag F1 indicating a vehicle speed V ≧ a predetermined vehicle speed V2 ... A determination permission flag F2 indicating that the vehicle has traveled at a predetermined vehicle speed V1 or more for a predetermined time C1 or more ... A flag F1 indicating that the vehicle has traveled at a predetermined vehicle speed V2 or more for a predetermined time C2 or more Judgment permission flag to indicate

CD1 ... Countdown timer CD2 ... Countdown timer V ... Vehicle speed T detected by vehicle speed sensor 5 ... Oil temperature Tmax detected by oil temperature sensor 4 The maximum oil temperature among the detected oil temperatures Tmin The minimum oil temperature among the detected oil temperatures CN1 ... A counter (RAM that measures the cumulative time in the coast state at vehicle speed V ≧ predetermined vehicle speed V1) CN2 ... A counter (provided in the memory of RAM) for measuring the cumulative time of the coast state at vehicle speed V ≧ predetermined vehicle speed V2.

Next, the flowchart will be described with reference to FIGS. When the control is started by turning on the ignition switch 10, the initial setting is first executed (S1). In this initial setting, the set value C is set in the timer TM.
The flag FF, FG1, FG2, F1, and F2 are all reset when 0 (for example, 180 seconds) is set and started. Then, the detected oil temperature T is read, both the maximum oil temperature Tmax and the minimum oil temperature Tmin are set to the detected oil temperature T, the timers CD1 and CD2 are cleared, and the counter C
N1 and CN2 are cleared.

Next, the vehicle speed V detected by the vehicle speed sensor 5
And the oil temperature T detected by the oil temperature sensor 4 and the idle SW
The signal (idle switch signal) is read (S2),
Next, it is determined whether the set time C0 set in the timer TM has elapsed (S3). The set value C0 is a time required for the oil to make at least one round in the automatic transmission 2 and the oil cooler to equalize the oil temperature of all the oil. The set time C0 is the set time C0. The amount of oil inside (for example, 6 liters) and the flow rate of the oil cooler (5 liters /
min) and

When the determination of S3 is No, S2 and S3 are repeatedly executed, but when the determination of S3 is Yes, the minimum oil temperature Tmin and the maximum oil temperature Tmax are updated in S4 as needed. That is, when the oil temperature T <the minimum oil temperature Tmin, the minimum oil temperature Tmin is updated by the oil temperature T, and when the oil temperature T> the maximum oil temperature Tmax, the maximum oil temperature Tmax is updated by the oil temperature T. . Next, in S5, when the vehicle speed V ≧ the predetermined vehicle speed V1 and the flag FG1 = 0, the flag FG1 is set and the timer CD1 is set to the predetermined time C1 and started. Similarly, when the vehicle speed V ≧ the predetermined vehicle speed V2 and the flag FG2 = 0, the flag FG2 is set and the timer CD2 is set to the predetermined time C2 to start the operation.

Next, at S6, if the flag FG1 = 1 and the idle switch 7 is ON, the counter CN
1 is incremented by 1. Further, the flag FG2 =
When it is 1 and the idle switch 7 is ON, the counter CN2 is incremented by one. Next, in S7, the flag FG1 is reset when the vehicle speed V <the predetermined vehicle speed V1, and similarly, the flag FG2 is reset when the vehicle speed V <the predetermined vehicle speed V2. Next, in S8,
It is determined whether the flag FG1 = 1 and the timer CD1 has timed out. When the determination in S8 is Yes, the counter CN1 sets the set value K1 (for example, K1 is 3 in S9).
It is determined whether or not the value is 0 sec or more). If the determination in S9 is Yes, the flag F1 is reset to prohibit the determination of whether or not there is a failure in S10, and then the process returns to S2.

If the determination in S9 is No, the determination permission flag F1 is set in S11, and the flag F
When G2 = 1 and the timer CD2 has not timed out, the timer CD2 is set to the predetermined time C2 and restarted, and then the process proceeds to S16. On the other hand, if the determination in S8 is No, it is determined in S12 whether the flag FG2 = 1 and the timer CD2 has timed out.
If the determination in S12 is Yes, it is determined in S13 whether the counter CN2 is equal to or greater than the set value K2 (for example, K2 is a value corresponding to 20 sec). If the determination in S13 is Yes, the flag F2 is reset in S14 in order to prohibit the determination of whether or not there is a failure, and then the process returns to S2. S
If the determination result in 13 is No, the determination permission flag F2 is set in S15, and if the flag FG1 = 1 and the timer CD1 has not timed out, the timer CD1 is set to the predetermined time C1 and then set again. Let's start
Then, the process proceeds to S16.

Next, in S16, it is determined whether or not both of the determination permission flags F1 and F2 are "1". If the determination is No, the process returns to S2, S2 and the subsequent steps are executed in the same manner as described above, and S2- While repeatedly executing S16,
If the determination is Yes, in S17, the maximum oil temperature Tma
The difference between x and the minimum oil temperature Tmin (oil temperature increase range) is a predetermined value ΔT0
(For example, 5 ° C.) or less is determined. Oil temperature sensor 4
Is normal, the detected oil temperature T gradually rises, so the value of (Tmax-Tmin) becomes sufficiently large, but when the oil temperature sensor 4 is out of order, Since the detected oil temperature T does not substantially change, (Tmax-Tmin) ≤
It becomes the predetermined value ΔT0.

Therefore, when the determination in S17 is No, the oil temperature sensor 4 is normal, so the fail flag FF is reset in S18, and then the process returns to S2, and S2 and subsequent steps are repeatedly executed. If the determination in S17 is Yes,
In S19, the fail flag FF is set, and a failure code indicating an oil temperature sensor failure is stored in the failure information memory of the RAM. Next, in S20, the display 8
“Oil temperature sensor failure” is displayed on the display to notify the driver of the failure of the oil temperature sensor 4, and then the process returns to S2, and S2 and subsequent steps are repeatedly executed. The failure determination control is continued until the ignition switch is turned off. However, if the oil temperature sensor 4 has a failure, S20 may be repeatedly executed without returning from S20 to S2. It is assumed that this failure determination control is executed by the interval interrupt processing at every predetermined minute time. The failure code stored in the failure information memory is supplied to the shift control for controlling the automatic transmission 2 and applied to adjust the shift control.

The operation of the failure determination device described above will be described. As described above, the predetermined low vehicle speed V1 and the high predetermined vehicle speed V2 are set, and the predetermined time C is equal to or more than the predetermined vehicle speed V1.
The oil temperature rises in the torque converter while the vehicle is traveling for one or more times, and the oil temperature rises in the transmission gear mechanism while the vehicle is traveling for a predetermined time C2 or more at a predetermined vehicle speed V2 or more. Therefore, it is possible to determine the failure of the oil temperature sensor 4 based on the oil temperature increase width after the vehicle travels such that both the oil temperature increase in the torque converter and the oil temperature increase in the transmission gear mechanism occur.

When the running state becomes a running state in which slippage between the pump of the torque converter and the turbine is small (that is, a coast state) immediately after the start of running, the oil temperature hardly rises, so the oil temperature sensor 4 is normal. Nevertheless, considering that it is easy to erroneously determine that a failure has occurred, the counter CN1
Thus, the cumulative time when the idle switch 7 is ON during the predetermined time period C1 is counted, the coast state is determined from the cumulative time, and in the coast state, the flag F1 is reset to prohibit the determination as to whether or not there is a failure. To do.
Similarly, the counter CN2 counts the cumulative time when the idle switch 7 is ON in the period of the predetermined time C2, determines the coast state from the cumulative time, and prohibits the determination as to whether or not there is a failure in the coast state. The flag F2 is reset. In this way, the coast state is determined, and in the coast state, the determination as to whether or not there is a failure is prohibited, so the accuracy and reliability of the failure determination can be improved.

Since the oil temperature increasing speed in the torque converter during low speed traveling is smaller than the oil temperature increasing speed in the transmission gear mechanism during high speed traveling, the predetermined time C1 is changed to the predetermined time C.
Since it is set to be larger than 2, the accuracy and reliability of failure determination can be ensured. Furthermore, as shown in S8 to S15,
During time counting of the predetermined time C1 and the predetermined time C2, when one time is up, the other time is reset and the time is read again. That is, as shown in FIG. 3, when the vehicle moves to a high speed running at a predetermined vehicle speed V2 or more immediately after the start of running, the predetermined time C1 and the predetermined time C2 are measured in parallel, but in this case, Compared with the case of non-parallel timing, the oil temperature rises until the failure is judged. Therefore, when one of the timers has timed up during the predetermined time C1 and the predetermined time C2, the other time is reset and the time is measured again. By fixing it, the accuracy and reliability of failure determination can be secured.

A timer TM is provided, and as shown in S3, the failure determination is performed after the set time C0 has elapsed from the engine start. That is, immediately after the engine is started, the oil in the oil sump of the automatic transmission 2 does not go around the automatic transmission 2 and the oil cooler, and the oil temperature of all the oil is not uniform. The failure determination is performed after the set time C0 has elapsed from the start. Since the time for the oil in the oil sump of the automatic transmission 2 to make a circuit in the automatic transmission 2 and the oil cooler is proportional to the amount of oil in the automatic transmission 2, the set time C0 is set based on the amount of oil. Is set as a value with a margin.

An indicator 8 is provided as a notifying means for informing the driver of the failure of the oil temperature sensor 4, and when the failure of the oil temperature sensor 4 is determined, the failure is displayed on the display 8, so the oil temperature sensor 4 The failure can be reliably notified to the driver, and countermeasures such as repairing the oil temperature sensor 4 can be taken. Further, a failure information memory is provided in the RAM backed up by the secondary battery, and when a failure of the oil temperature sensor 4 is determined, the failure code is stored in the failure information memory. It can be used to display the failure of or to adjust the shift control.

Next, the failure determination control according to the first alternative embodiment will be described. In this failure determination control, it is determined whether or not there is a failure from the increase range of the oil temperature after traveling for a predetermined time at a predetermined vehicle speed V1 or more after the start of traveling, but in the coast state (deceleration traveling or downhill traveling) Since there is almost no slippage in the torque converter and the oil temperature rise rate is small, the predetermined time is set to a long time. In the non-coast state, there is slippage in the torque converter and the oil temperature rise rate is larger than in the coast state. , The predetermined time is set shorter than the predetermined time in the coast state.

Explaining with reference to the flow charts of FIGS. 6 and 7, when the control is started by turning on the ignition switch 10, the initial setting is first executed (S3).
0). In this initial setting, the timer TM is set to the set value C0 (for example, 180 seconds) and started, and the flag F is set.
F and FG are reset and the timer CD is cleared. Then, the detected oil temperature T is read, and both the maximum oil temperature Tmax and the minimum oil temperature Tmin are set to the detected oil temperature T.

Next, the vehicle speed V detected by the vehicle speed sensor 5
And the throttle opening TVO detected by the throttle opening sensor 6 and the oil temperature T detected by the oil temperature sensor 4 are read (S31), and then the set time C set in the timer TM is set.
It is determined whether 0 has elapsed (S32). The setting value C0 is the same as in the above embodiment.

If the determination in S32 is No, S31 and S32
Is repeatedly executed, but when the determination in S32 is Yes, the minimum oil temperature Tmin and the maximum oil temperature Tmax are updated in S33 as needed. That is, oil temperature T <minimum oil temperature Tmi
In the case of n, the minimum oil temperature Tmin is updated with the oil temperature T, and
When the oil temperature T> the maximum oil temperature Tmax, the maximum oil temperature Tmax is updated with the oil temperature T. Next, in S34, vehicle speed V ≧ predetermined vehicle speed V1 (for example, 25 km / h) and flag FG =
It is determined whether it is 0 and the coasting state. In this case, as shown in FIG. 8, it is determined that the vehicle is in the coast state when the vehicle is below the no-road line based on a map preset with the vehicle speed V and the throttle opening TVO as parameters.

When the determination in S34 is Yes, the flag FG is set in S35 and the timer CD is set to a predetermined time K01 to start. If the determination in S34 is No, it is determined in S36 whether the vehicle speed V ≧ the predetermined vehicle speed V1 and the flag FG = 0, and whether the vehicle is in a non-coast state. If the determination is Yes, the flag FG is set and the timer is set in S37. CD for a predetermined time
Set K02 and start. However, the predetermined time K01
Is set to be larger than the predetermined time K02 (for example, about twice).

Next, in S38, vehicle speed V <predetermined vehicle speed V
If it is Yes, the flag FG is reset in S39, and the vehicle speed V ≧ the predetermined vehicle speed V1.
In the case of, the flag FG is not changed. Next, in S40, it is determined whether the flag FG = 1 and the count value CD = 0 of the timer CD. If the determination is No, S
Returning to S31, S31 and subsequent steps are repeatedly executed, and if the determination in S40 becomes Yes after a certain period of time elapses, S41 is executed.
At, it is determined whether the difference between the maximum oil temperature Tmax and the minimum oil temperature Tmin is less than or equal to a predetermined value ΔT0 (for example, 5 ° C.). When the oil temperature sensor 4 is normal, the detected oil temperature T gradually rises, so the value of (Tmax-Tmin) becomes sufficiently large, but the oil temperature sensor 4 is out of order. In this case, since the detected oil temperature T does not substantially change, (Tmax-
Tmin) ≦ predetermined value ΔT0.

Therefore, when the determination in S41 is No, the oil temperature sensor 4 is normal, so the fail flag FF is reset in S42, and then the process returns to S31 and S31.
The subsequent steps are repeatedly executed. If the determination in S41 is Yes, the fail flag FF is set in S42 and the failure code indicating the oil temperature sensor failure is stored in the failure information memory in the RAM. Next, in S43, "oil temperature sensor failure" is displayed on the display 8 to notify the driver of the failure of the oil temperature sensor 4, and then the process returns to S31 and S3.
1 and subsequent steps are repeatedly executed. This failure judgment control is continued until the ignition switch is turned off.
If the oil temperature sensor 4 is out of order, S44 to S3
S44 may be repeatedly executed without returning to 1. It is assumed that this failure determination control is executed by the interval interrupt processing at every predetermined minute time.

The operation of this failure determination control will be described. A timer CD that keeps track of the running period at a prescribed vehicle speed V1 or higher
In the non-coast state, set K02 for a predetermined time to start, and in the coast state for a predetermined time K02
It is configured to start with a longer predetermined time K01, and when the coast condition is set, the determination in S41 is made after the predetermined predetermined time K01 has elapsed than in the non-coast condition. You can improve your sex. That is, in the coast state, slippage between the pump of the torque converter and the turbine hardly occurs, and the oil temperature rising speed in the automatic transmission is also small, so the predetermined time K0
By setting 1 to be larger than the predetermined time K02, it is possible to reduce erroneous determination that the oil temperature sensor 4 is malfunctioning although it is normal.

Next, the failure determination control according to the second alternative embodiment will be described. As shown in FIG. 9, in addition to the configuration of FIG. 1, an engine speed sensor 11 for detecting the engine speed and a turbine speed sensor 12 for detecting the speed of the turbine of the automatic transmission 2 are also provided. The detection signals of these sensors 11 and 12 are also supplied to the control unit 3. Next, a routine for failure determination control will be described with reference to FIG. When the control is started by turning on the ignition switch 10, the initial setting is first executed (S50). In this initial setting, the timer TM is set to a set value C0 (for example, 180 sec) and started, the flag FF is reset, and the cumulative slip index X is reset. Then, the detected oil temperature T is read, and both the maximum oil temperature Tmax and the minimum oil temperature Tmin are set to the detected oil temperature T.

Next, the engine speed Ne, the turbine speed Nt, and the oil temperature T are read (S51), and it is then determined whether or not the set time C0 set in the timer TM has elapsed (S52). , If the judgment is No, S51 and S
52 is repeated, and when the set time C0 has elapsed, S
At 53, the minimum oil temperature Tmin and the maximum oil temperature Tmax are updated as needed. That is, when the oil temperature T <the minimum oil temperature Tmin, the minimum oil temperature Tmin is updated with the oil temperature T, and when the oil temperature T> the maximum oil temperature Tmax, the maximum oil temperature Tmax is the oil temperature Tmax. Will be updated with.

Next, the slip s corresponding to the slip between the pump of the automatic transmission 2 and the turbine is calculated as the difference (Ne-Nt) between the engine speed Ne and the turbine speed Nt (S54), and then The slip s is applied to the map of FIG. 11 preset in the ROM to calculate the increment G (s) of the cumulative slip index (S55), and then the cumulative slip index X is calculated as the previous cumulative slip index X. To this increase G
It is calculated as a value obtained by adding (s) (S56). The cumulative slip index X is an index indicating the degree of slip between the pump and the turbine of the automatic transmission 2, and in a traveling state (coast state) in which slip between the pump and the turbine is small,
The cumulative slip index X becomes smaller.

Next, in S57, the cumulative slip index X
Is greater than or equal to the set value X0, and if the determination is No, the process returns to S51 and S51 is repeatedly executed, and the cumulative slip index X gradually increases during that time. When the cumulative slip index X becomes equal to or larger than the set value X0 after a certain amount of time has passed, the process proceeds to S58 and the increase range of the oil temperature (Tmax-T
min) is below a predetermined value ΔT0 (for example, 5 ° C.). When the oil temperature sensor 4 is normal, the detected oil temperature T gradually rises, so (Tmax-Tmin
) Becomes sufficiently large, but when the oil temperature sensor 4 is out of order, the detected oil temperature T does not substantially change, so that (Tmax-Tmin) ≦ predetermined value ΔT0.

Therefore, when the determination in S58 is No, the oil temperature sensor 4 is normal, so the fail flag FF is reset in S59, and then the process returns to S51 and S51.
The subsequent steps are repeatedly executed. If the determination in S58 is Yes, the fail flag FF is set in S60, and a failure code indicating an oil temperature sensor failure is stored in the failure information memory in the RAM. Next, in S61, "oil temperature sensor failure" is displayed on the display 8 to notify the driver of the failure of the oil temperature sensor 4, and then the process returns to S51 and S51.
The subsequent steps are repeatedly executed. The failure determination control is continued until the ignition switch is turned off. However, if the oil temperature sensor 4 has a failure, the steps S61 to S51 are performed.
S61 may be repeatedly executed without returning to.
It should be noted that this failure determination control is executed by interval interrupt processing at every predetermined minute time.

In this failure determination control, the oil temperature increasing speed is large in the normal traveling state where the slip between the pump of the automatic transmission 2 and the turbine is not small, and is increased in the traveling state where the slip is small. Paying attention to the fact that becomes smaller, the cumulative slip index X reflecting the degree of slip between the pump and the turbine is introduced.
Since the determination of S58 is made after the predetermined value X0 is reached, when the running state in which the slip between the pump and the turbine is small and the oil temperature rise rate is small is compared with the running state in which the slip is not small, As a result, the time until the cumulative slip index X reaches the predetermined value X0 becomes long, so that the accuracy and reliability of failure determination can be improved.

Next, a modification in which the failure determination control in the above embodiment and another embodiment is partially modified will be described. 1] In the failure determination control of FIGS. 4 and 5, CN1 ≧
When it is K1, the flag F1 is set and then S17
The decision threshold value ΔT0 used in step C is changed to a smaller value, and C
When N2 ≧ K2, after setting the flag F2,
The determination threshold value ΔT0 used in S17 may be changed to a smaller value. That is, when the determination threshold value ΔT0 is changed to a small value, the failure determination (determination of failure) in S17 is less likely to occur, so that an erroneous determination that the oil temperature sensor 4 is in failure although normal is less likely to occur. Become.

2) In the failure determination control shown in FIGS. 4 and 5, the condition of "idle SW = ON" in S6 may be changed to a condition of "running state = coast state". In that case, the determination as to whether or not the coast state is made is based on the map shown in FIG. 3] In the failure determination control of FIGS. 6 and 7, the predetermined times K01 and K02 are set to different values in the coast state and the non-coast state, but the predetermined time is set in common and In the case of the coast state, the determination threshold value ΔT0 in S42 may be changed to a smaller value, as in the case of [].

4] In the failure determination control of FIG. 10, the failure determination control is configured to be performed regardless of the vehicle speed V, but the steps S54 to S56 are executed only when the vehicle speed V1 or higher. You may comprise. 5] Instead of the display unit 8, a display lamp may be provided on the instrument panel, and when the failure of the oil temperature sensor 4 is determined, the display lamp may be turned on. Further, the control unit may be configured only for failure determination control of the oil temperature sensor without also being used as a control device for the automatic transmission. 6) The present invention can be similarly applied to not only a device for determining a failure of an oil temperature sensor of an automatic transmission of an automobile but also a device for determining a failure of an oil temperature sensor of an automatic transmission of various vehicles. .

[0054]

According to the first aspect of the invention, the failure determining means for determining the failure of the oil temperature detecting means based on the increase in the oil temperature before and after the start of traveling is used as the failure determining means between the pump and the turbine of the torque converter of the automatic transmission. Since the failure determination suppressing means is provided to make it more difficult to make a failure determination in a running state with less slippage than in a traveling state with large slippage, it is difficult to make a failure determination in a running state with small slippage in the torque converter. , It becomes difficult to make an erroneous determination that there is a failure. Therefore, the accuracy and reliability of failure determination can be improved.

According to the second aspect of the present invention, the same effect as that of the first aspect is obtained, but the running state with small slippage is a coast state in which the engine load is equal to or less than a predetermined value determined according to the vehicle speed, and failure determination is suppressed. Since the means has a coast judging means for judging the coast state, the coast judging means (deceleration traveling state or downhill traveling state)
It is possible to secure the accuracy and reliability of the failure determination by making it difficult to make a failure determination that the oil temperature detection means is in failure in the coast state.

According to the invention of claim 3, the same effect as that of claim 2 is obtained, but the coast judging means is in the coast state when the accumulated time of the idle switch ON during traveling is equal to or more than a set value. Since the determination is made, the coast state can be surely determined, and the accuracy and reliability of the failure determination can be ensured.

According to the invention of claim 4, the same effect as that of claim 2 is obtained, but since the coast determining means determines the coast state based on the vehicle speed and the throttle opening, the vehicle speed and the throttle opening are determined. It is possible to reliably determine the coasting state below the no-load line, which is set as the parameters and, based on the vehicle speed and the throttle opening.

According to the fifth aspect of the present invention, the same effect as that of the first aspect is obtained, but the failure determination means sets the oil temperature when the vehicle has traveled at a predetermined vehicle speed or higher for a predetermined time or more with respect to the oil temperature before the start of travel. The failure of the oil temperature detection means is determined based on the increase amount. If the vehicle travels at a predetermined vehicle speed or higher for a predetermined time or longer, the oil temperature rises due to slippage between the pump and turbine of the torque converter or agitation of oil in the speed change gear mechanism in the normal case other than the coast state. The failure of the oil temperature detection means can be determined based on the increase amount of

According to the invention of claim 6, the same effect as in claim 5 is obtained, but the predetermined time is longer in the failure determination suppressing means in the traveling state with less slippage than in the other traveling states. Set. Since the oil temperature rising speed in the torque converter is small in the traveling state with small slip, the accuracy and reliability of the failure determination can be secured by setting the predetermined time longer than in the other traveling states.

According to the invention of claim 7, the same effect as that of claim 1 or claim 5 is obtained, but the failure judgment suppressing means is:
The determination threshold is set to be smaller in the traveling state with less slippage than in the other traveling states. Since the oil temperature rising speed in the torque converter is small when the vehicle is running with a small amount of slippage, it is possible to ensure the accuracy and reliability of failure determination by setting the determination threshold value smaller than when the vehicle is running other than that. .

According to the invention of claim 8, the same effect as that of claim 1 can be obtained, but the failure judgment suppressing means prohibits the failure judgment in the traveling state with small slip. When the vehicle is running with a small amount of slip, the speed of oil temperature rise in the torque converter is small, so that an erroneous determination is likely to occur.

According to the invention of claim 9, the same effect as that of claim 1 is obtained, but since the notifying means for notifying the driver of the failure of the oil temperature detecting means is provided, this notifying means
It is possible to notify the driver of the failure of the oil temperature detecting means, and take measures such as repairing the oil temperature detecting means.

According to the tenth aspect of the invention, the same effect as that of the first aspect is obtained, but since the storage means for storing the information of the failure of the oil temperature detecting means is provided, the information of the failure is stored in the oil temperature detecting means. It can be used to display a fault or can be applied to adjust the shift control. According to the invention of claim 11, the same effect as that of claim 1 is obtained, but since the start of running is the start of running following the ignition switch ON of the engine, the increase amount of the oil temperature before and after the start of running is accurately determined. Therefore, the accuracy and reliability of failure determination can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing an overall configuration of an oil temperature sensor failure determination device according to an embodiment of the present invention.

FIG. 2 is a time chart showing changes in vehicle speed, oil temperature, flags and the like.

FIG. 3 is a time chart showing changes in vehicle speed and flags.

FIG. 4 is a part of a flowchart of failure determination control.

5 is the rest of the flowchart of FIG.

FIG. 6 is a part of a flowchart of failure determination control according to the first alternative embodiment.

7 is the rest of the flowchart of the failure determination control of FIG.

FIG. 8 is a diagram of a map in which a no-load line is set.

FIG. 9 is a block diagram showing the overall configuration of an oil temperature sensor failure determination device according to a second alternative embodiment.

10 is a flow chart of failure determination control in the oil temperature sensor failure determination device of FIG.

11 is a diagram of a map in which the increment G (s) in the failure determination control of FIG. 10 is set with the slip s as a parameter.

[Explanation of symbols]

 2 Automatic transmission 3 Control unit 4 Oil temperature sensor 5 Vehicle speed sensor 6 Throttle opening sensor 8 Indicator 11 Engine speed sensor 12 Turbine speed sensor

Claims (11)

[Claims] 1. A failure determination device for determining a failure of an oil temperature detecting means for detecting an oil temperature of an automatic transmission of a vehicle, which receives a detection result of the oil temperature detecting means and increases the oil temperature before and after starting traveling. A failure determination means for determining that the oil temperature detection means is in failure when the amount is equal to or less than a predetermined determination threshold is provided, and the failure determination means has a small slip between the pump and the turbine of the torque converter of the automatic transmission. A failure determination device for an oil temperature detection means of an automatic transmission, comprising failure determination suppression means for making a failure determination less likely to occur in a running state than in a running state with large slippage. 2. The running state with small slippage is a coasting state in which the engine load is equal to or less than a predetermined value determined according to the vehicle speed, and the failure determination suppressing means includes a coasting determination means for determining the coasting state. Claim 1
A failure determination device for the oil temperature detection means of the automatic transmission as described in. 3. The oil for an automatic transmission according to claim 2, wherein the coast determination means determines that the vehicle is in a coast state when the accumulated time of the idle switch ON during traveling is equal to or more than a set value. Failure determination device for temperature detection means. 4. The failure determination device for oil temperature detection means of an automatic transmission according to claim 2, wherein the coast determination means determines the coast state based on a vehicle speed and a throttle opening. 5. The failure determination means determines the failure of the oil temperature detection means based on the amount of increase in the oil temperature when the vehicle has traveled at a predetermined vehicle speed or higher for a predetermined time or more with respect to the oil temperature before the start of travel. The failure determination device for the oil temperature detection means of the automatic transmission according to claim 1. 6. The automatic transmission according to claim 5, wherein the failure determination suppressing unit sets the predetermined time longer in a traveling state with less slippage than in other traveling states. Failure determination device for oil temperature detection means. 7. The failure determination suppressing means sets the determination threshold value to be smaller in a running state with less slippage than in other running states.
Alternatively, the failure determination device of the oil temperature detection means of the automatic transmission according to claim 5. 8. The failure determination device for the oil temperature detection means of an automatic transmission according to claim 1, wherein the failure determination suppression means prohibits failure determination in a traveling state in which slippage is small. 9. The failure determination device for oil temperature detection means of an automatic transmission according to claim 1, further comprising notification means for notifying a driver of a failure of the oil temperature detection means. 10. The failure determination device for the oil temperature detection means of an automatic transmission according to claim 1, further comprising storage means for storing information on a failure of the oil temperature detection means. 11. The failure determination device for the oil temperature detection means of an automatic transmission according to claim 1, wherein the start of running is the start of running subsequent to turning on an ignition switch of the engine.