JPH08219274A - Failure diagnostic device of automatic transmission - Google Patents

Abstract

PURPOSE: To correctly diagnose the oil amount in an automatic transmission without newly providing a detector by making a judgement that the oil level in the automatic transmission is lower than the prescribed value when the detected input shaft rotational speed, the operated speed difference and the detected deceleration are below the prescribed values. CONSTITUTION: An abnormality judging part 10d indicates the vehicle speed changing ratio, i.e., the deceleration below the prescribed value when the signal to prevent the engine stall is outputted, i.e., when the difference in the rotational speed between the input and output of a torque converter 3, and the speed of the engine 1 is below the prescribed value. When the vehicle is detected to be in the rapidly decelerated condition, the level of the AT oil in an automatic transmission 2 is below the prescribed level, a lock-up piston is moved to the pump impeller side to apply the excessive load on the engine 1 due to the sliding friction, and a judgement is made that the speed of the engine 1 is lowered, and the judgement is stored in a memory 10c and an alarm is given by an alarming device 11.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a failure diagnosing device for an automatic transmission equipped with a torque converter having a lockup mechanism, and more particularly to diagnosing the oil amount in the automatic transmission.

[0002]

2. Description of the Related Art Generally, a torque converter of an automatic transmission that transmits engine power to the transmission side using automatic transmission oil as a medium is inferior in transmission efficiency to a mechanical transmission. For this reason, in recent years, torque converters have been used that are equipped with a lock-up mechanism that directly connects the input and output shafts of the torque converter as necessary to avoid slip loss.

FIG. 3 shows a cross section of a torque converter having a lockup mechanism. This torque converter is
It is a three-element one-stage two-phase type that includes a pump impeller 31 connected to the input shaft, a turbine runner 32 connected to the output shaft, and a stator 33 fixed to the converter housing. When the input shaft is rotationally driven by the engine, the pump impeller 31 rotates and the pump impeller 3
1 and the turbine runner 32 are filled with automatic transmission oil (hereinafter referred to as AT oil), and the turbine runner 32 rotates. At this time, the stator 33 rectifies the flowing AT oil to generate a torque increasing action. A lockup piston 34 is provided on the output shaft of the torque converter. In the drive region where the torque increasing action is not necessary, the AT oil is guided from the oil passage A to the P2 portion in the torque converter, and further returns from the oil passage B to the oil pan (not shown). As a result, the lockup piston 34 is driven in the direction opposite to the arrow in the figure, the lockup piston 34 is crimped to the pump impeller 31, and the pump impeller 31 and the turbine runner 32 are directly connected. On the other hand, in the drive range where the torque increasing action is required, the AT
Oil is guided from the oil passage B to the portion P1 in the torque converter, and then returns from the oil passage A to the oil pan. As a result, the lock-up piston 34 is driven in the direction of the arrow in the figure, and the lock-up piston 34 is moved to the pump impeller 31.
Away from the pump impeller 31 and turbine runner 3
The direct connection with 2 is released. The AT oil supply direction to the torque converter is switched by a lock-up control valve (not shown).

By the way, as shown in FIG. 3, when the torque converter is mounted so that the input / output axis direction of the torque converter coincides with the front-rear direction of the vehicle, the AT oil in the automatic transmission is regulated by a specified amount for some reason. When the pressure is further reduced, the operating pressure in the torque converter is reduced, and the lock-up piston 34 may easily move back and forth due to a reaction that accompanies acceleration and deceleration of the vehicle. For example,
At the time of sudden deceleration, the lockup piston 34 moves to the pump impeller 31 side, so that an excessive load is applied to the engine due to sliding friction and the engine speed is reduced.

Therefore, it is conceivable to equip the oil pan of the automatic transmission with a sensor for detecting the amount of AT oil so that the amount of AT oil is constantly monitored. However,
The amount of oil in the oil pan largely deviates depending on the traveling state of the vehicle such as acceleration / deceleration, traveling on a slope, traveling on a road surface with a cant, etc. Therefore, it is difficult to determine the reference position, and there is a risk of erroneous determination.

An object of the present invention is to provide a diagnostic device for an automatic transmission which accurately diagnoses the oil amount of the automatic transmission without newly providing a detector.

[0007]

In order to achieve the above object, the invention of claim 1 is an automatic transmission failure diagnosing device having a torque converter having a lock-up mechanism, wherein an input of the torque converter is provided. Input shaft speed detecting means for detecting a shaft rotating speed, output shaft speed detecting means for detecting an output shaft rotating speed of the torque converter, input shaft rotating speed detected by the input shaft speed detecting means and the output shaft speed Speed difference calculation means for calculating the speed difference from the output shaft rotation speed detected by the detection means, deceleration detection means for detecting the deceleration of the vehicle, and input shaft rotation speed detected by the input shaft speed detection means. Is a predetermined value or less, the speed difference calculated by the speed difference calculating means is a predetermined value or less, and the deceleration detected by the deceleration detecting means is a predetermined value or less. For comprises a a determining oil quantity determining means automatic transmission oil is lower than the specified amount. According to a second aspect of the invention, a failure diagnosis device for an automatic transmission detects the rotation speed of an engine directly connected to the input shaft of the torque converter by the input shaft speed detection means. The automatic transmission failure diagnosing device according to claim 3 has a vehicle speed detecting means for detecting the traveling speed of the vehicle in the deceleration detecting means, and the vehicle deceleration based on the traveling speed detected by the vehicle speed detecting means. The speed is calculated. 5. The failure diagnosis device for an automatic transmission according to claim 4, wherein the deceleration detecting means has an automatic transmission output shaft speed detecting means for detecting an output shaft rotation speed of the automatic transmission, and the automatic transmission output shaft speed. The deceleration of the vehicle is calculated based on the output shaft rotation speed detected by the detection means. According to a fifth aspect of the present invention, there is provided a failure diagnosis device for an automatic transmission, comprising warning means for giving a warning when the oil amount determination means determines that the automatic transmission oil is lower than a prescribed amount. A failure diagnosis device for an automatic transmission according to claim 6, further comprising: storage means for storing the determination result of the oil amount determination means, and output means for outputting the determination result stored in the storage means. Is.

[0008]

In the automatic transmission failure diagnosing device according to claim 1, the input shaft rotation speed of the torque converter is not more than a predetermined value, and the speed difference between the input shaft rotation speed and the output shaft rotation speed of the torque converter is a predetermined value. When the deceleration of the vehicle is equal to or less than the predetermined value, it is determined that the automatic transmission fluid is lower than the specified amount. According to another aspect of the failure diagnosis device for an automatic transmission of the present invention, the rotation speed of the engine directly connected to the input shaft of the torque converter is detected and used as the input shaft rotation speed of the torque converter. In the automatic transmission failure diagnosis device according to the third aspect, the traveling speed of the vehicle is detected, and the deceleration of the vehicle is calculated based on the detected traveling speed. In the automatic transmission failure diagnosis device according to the fourth aspect, the output shaft rotation speed of the automatic transmission is detected, and the deceleration of the vehicle is calculated based on the detected output shaft rotation speed. According to another aspect of the failure diagnosis device for an automatic transmission of the present invention, a warning is issued when it is determined that the automatic transmission oil is lower than a specified amount. In the automatic transmission failure diagnosis device according to the sixth aspect, the determination result of the oil amount is stored, and the stored determination result is output.

[0009]

FIG. 1 is a block diagram showing the structure of an embodiment. Reference numeral 1 is an engine of a vehicle, 2 is an automatic transmission, and the power of the engine 1 is transmitted to an automatic transmission 2 via a torque converter 3. In this embodiment, the torque converter 3 is mounted on the vehicle so that the input / output axis direction of the torque converter 3 coincides with the longitudinal direction of the vehicle. Further, the structure of the torque converter 3 is as shown in FIG.
The structure is similar to that shown in FIG. 3, and this embodiment will be described with reference to FIG. Reference numeral 4 is an oil pan for storing the AT oil circulated in the automatic transmission, and a control valve 4a is mounted in the oil pan. The control valve 4 a controls gear shifting of the automatic transmission 2, lockup of the torque converter 3, and hydraulic pressure of a hydraulic control device that controls the automatic transmission 2 and the torque converter 3. The control valve 4a may be mechanical or electronic.

Engine control unit 5 (hereinafter,
The ECM 5) controls the fuel injection amount of the engine 1 and the ignition timing. Signals from various sensors are input to the ECM 5, including an engine rotation sensor 6 provided at a portion that rotates in synchronization with the engine such as a crankshaft or a camshaft, and the ECM 5 sends a control signal according to a running state. It outputs to the electronic control actuator 7 provided in the engine 1. Electronically controlled actuator 7
Has a function of supplying fuel. The output signal of the engine rotation sensor 6 represents the rotation speed of the engine 1, that is, the rotation speed per unit time (hereinafter, simply referred to as engine rotation speed) NENG, and the input shaft rotation speed of the torque converter 3, that is, the input per unit time. It represents the shaft rotation speed (hereinafter, simply referred to as the input shaft rotation speed). Further, the input shaft of the automatic transmission 2 is provided with an automatic transmission input shaft rotation sensor 8 for measuring the rotation speed of the automatic transmission input shaft. The output signal of the rotation sensor 8 represents the output shaft rotation speed of the torque converter 3, that is, the output shaft rotation speed per unit time (hereinafter, simply referred to as the output shaft rotation speed) NTBN. On the other hand, the output shaft of the automatic transmission 2 is provided with a sensor 9 for measuring the rotation speed of the output shaft, and the vehicle speed VSP is obtained based on the measured rotation speed. Below, this sensor 9 is called a vehicle speed sensor.

The diagnostic device 10 is composed of a microcomputer and peripheral parts such as a memory 10e and is composed of software.
a, a deceleration calculation unit 10b, an engine stall prevention unit 10c, and an abnormality determination unit 10d. The torque converter input / output rotational speed difference calculation unit 10a uses a rotational speed difference between the pump impeller 31 and the turbine runner 32 of the torque converter 3, that is, a rotational speed difference per unit time (hereinafter, simply referred to as rotational speed difference) R.
TC (= NENG-NTBN) is calculated, and the deceleration calculation unit 10b calculates the rate of change ΔVSP of the vehicle speed signal VSP per unit time, that is, the deceleration. Further, the engine stall prevention unit 10c outputs a signal for engine stall prevention to the ECM 5 when an extra load is applied to the engine 1 due to the movement of the lockup piston 34 in a rapid deceleration state and an engine stall is predicted to occur, and an abnormality occurs. The determination unit 10d determines whether or not the AT oil has a specified amount, based on the deceleration state of the vehicle when the engine stall prevention unit 10c outputs a signal for engine stall prevention. The determination result of the oil amount by the abnormality determination unit 10d is stored in the memory 1
0e is stored.

The vehicle speed signal VSP measured by the vehicle speed sensor 9 is converted into a rate of change ΔVSP per unit time, that is, a deceleration signal, by a deceleration calculation unit 10b, and a torque converter input / output rotation speed difference calculation unit 10a and an abnormality determination unit 10d. Is output to. When the torque converter input / output speed difference calculation unit 10a recognizes that the vehicle is in a decelerating state by the deceleration signal ΔVSP sent from the deceleration calculation unit 10b, the output of the engine rotation sensor 6 and the automatic transmission input shaft rotation sensor 8 is output. Signal N
Start monitoring ENG and NTBN and calculate torque converter input / output speed difference RTC (NENG-NTBN). The calculated torque converter input / output rotational speed difference RTC is sequentially output to the engine stall prevention unit 10c. In addition to the torque converter input / output rotational speed difference RTC, the engine speed NENG measured by the engine speed sensor 6 is also input to the engine stall prevention unit 10c.
While the vehicle is decelerating, the torque converter input / output speed difference RTC is a predetermined value R
When the engine speed NENG becomes equal to or lower than the predetermined value N2, the lock-up piston 34 moves to the pump impeller 31 side and an extra load is applied to the engine 1 due to sliding friction. It is judged that it has decreased, and the signal for engine stall prevention is set to ECM5.
Output to. Upon receiving this signal, the ECM 5 outputs a control signal for preventing an engine stall, such as increasing the fuel supply amount, to the electronic control actuator 7.

When the signal for preventing the engine stall is output, the abnormality determining section 10d determines that the torque converter input / output rotational speed difference RTC is less than a predetermined value R and the engine rotational speed NENG is less than a predetermined value N2. The vehicle speed change rate ΔV
If SP, that is, the deceleration is less than the predetermined value α3 and it is detected that the vehicle is in a sudden deceleration state, A in the automatic transmission 2 is detected.
T-oil has dropped below the specified amount, and lock-up piston 3
4 is moved to the pump impeller 31 side and the sliding friction causes an extra load on the engine 1 to determine that the rotational speed of the engine 1 has decreased, and the fact is stored in the memory 10e and a warning device 11 warns. Do. The diagnostic information output device 12 sends a predetermined output command to the memory 10e, reads the stored contents including the oil amount diagnostic result, and displays it on the display or prints it on a predetermined check sheet.

FIG. 2 is a flowchart showing a diagnostic program of the diagnostic device 10. According to this flowchart,
The operation of diagnosing the oil amount of the automatic transmission 2 by the diagnostic device 10 will be described. The microcomputer of the diagnostic device 10 repeatedly executes this diagnostic program while the vehicle is traveling.
In step 10, monitoring of the vehicle speed signal VSP input from the vehicle speed sensor 9 is started. The vehicle speed signal VSP is always monitored during the execution of this program. In the following step 20, it is determined whether or not the rate of change ΔVSP of the vehicle speed signal VSP input from the vehicle speed sensor 9 is smaller than a predetermined value α1 indicating the deceleration state. Here, the vehicle speed change rate ΔVSP takes a positive value during acceleration and takes a negative value during deceleration. The predetermined value α1 may be set to 0 or a small negative value, for example. When the deceleration state of the vehicle is detected with ΔVSP <α1, the process proceeds to step 40, and otherwise proceeds to step 30. When ΔVSP ≧ α1 and the vehicle is not in the deceleration state, in step 30, the engine rotation sensor 6
It is determined whether or not the engine speed NENG measured by means of is less than or equal to a predetermined value N1. Here, the predetermined value N1 is
For example, set a rotational speed slightly lower than the idling rotational speed. When NENG ≦ N1, it is judged that the engine 1 has stopped, and the execution of the program is terminated. When NENG> N1, the process returns to step 20.

When the deceleration state of the vehicle is detected, in step 40, the engine speed NENG input from the engine rotation sensor 6 and the automatic transmission input shaft rotation input from the automatic transmission input shaft rotation sensor 8 are detected. The engine speed NEN is monitored in step 50 by monitoring the number NTBN.
The difference between G and the input shaft speed NTBN of the automatic transmission, that is, the torque converter input / output speed difference RTC is calculated. Next Step 60
Then, whether or not the engine speed NENG measured in step 40 is less than or equal to the predetermined value N2 and the input / output speed difference RTC calculated in step 50 is less than or equal to the predetermined value R, that is, lockup in the decelerated state. It is determined whether or not the engine 1 will be overloaded due to the movement of the piston 34 and the occurrence of engine stall is predicted. Here, the predetermined value N2 is
For example, the idling speed or a speed slightly higher than that may be set. Further, the predetermined value R may be set to an appropriate value of 0 to several 100 r / m, for example.
If NENG≤N2 and RTC≤R and the occurrence of engine stall is predicted, the routine proceeds to step 80, and if not, the routine proceeds to step 70. When there is no fear of engine stall, it is determined in step 70 whether the rate of change ΔVSP of the vehicle speed signal VSP input from the vehicle speed sensor 9 is larger than a predetermined value α2 indicating that the deceleration state has ended. . Here, for example, 0 or a small positive value may be set as the predetermined value α2. When ΔVSP> α2 and the deceleration state ends, the process returns to step 10 and the execution of this diagnostic program is repeated. When ΔVSP ≦ α2 and the deceleration state does not end, the process returns to step 40 and the occurrence of engine stall is monitored again.

When NENG ≧ N2 and RTC ≧ R, it is predicted that the engine stall will occur. Therefore, in step 80, a signal for preventing engine stall is output to the ECM 5. Step 9
At 0, it is determined whether or not the rate of change ΔVSP of the vehicle speed signal VSP input from the vehicle speed sensor 9 at the time when step 40 is executed or the time closest to that time is less than or equal to a predetermined value α3. Here, the predetermined value α3 is a reference value for determining that engine stall is predicted to occur due to a decrease in AT oil, and the predetermined value α3 is, for example, actually A
The T oil may be drained, abrupt deceleration may be performed in a state where the amount of oil is lower than the specified amount, and the setting may be made based on the deceleration when the engine stall occurs. When the rapid deceleration state of the vehicle is detected with ΔVSP ≦ α3, the process proceeds to step 100, otherwise returns to step 10. In step 100, it is stored in the memory 10e that the AT oil of the automatic transmission 2 is lower than the specified amount, and in the following step 110, the warning device 11 warns and the process ends.

In the embodiment described above, the output shaft of the automatic transmission 2 is provided with the sensor 9 for measuring the rotation speed, and the vehicle speed VSP is detected based on the measured rotation speed. However, the vehicle speed VSP is detected. The method is not limited to the embodiments described above.

In the structure of the above embodiment, the engine rotation sensor 6 serves as the input shaft speed detecting means, the automatic transmission input shaft rotation sensor 8 serves as the output shaft speed detecting means, and the torque converter input / output speed difference calculating section 10a serves as the speed. The difference calculation means, the deceleration calculation portion 10b is the deceleration detection means, the abnormality determination portion 10d is the oil amount determination means, the vehicle speed sensor 9 is the vehicle speed detection means and the automatic transmission output shaft speed detection means, and the warning device 11 is. The memory 10E constitutes a storage means, and the diagnostic information output device 12 constitutes an output means.

[0019]

As described above, according to the present invention, the input shaft rotation speed of the torque converter is equal to or lower than a predetermined value, and the speed difference between the input shaft rotation speed and the output shaft rotation speed of the torque converter is a predetermined value. If the deceleration of the vehicle is equal to or less than the predetermined value, it is determined that the automatic transmission oil is lower than the specified amount, so the oil amount of the automatic transmission does not need to be newly provided. Can be accurately diagnosed. The rotation speed of the engine directly connected to the input shaft of the torque converter may be detected and used as the rotation speed of the input shaft of the torque converter. Further, the deceleration of the vehicle may be calculated by detecting the traveling speed of the vehicle and based on the detected traveling speed, or by detecting the output shaft rotation speed of the automatic transmission and detecting the output shaft rotation speed. You may calculate based on. Further, since the warning is issued when it is determined that the automatic transmission oil is lower than the specified amount, it is possible to immediately perform appropriate inspection and repair. Furthermore, since the determination result of the oil amount is stored and the stored determination result is output, the oil amount is diagnosed during normal traveling,
The diagnostic result can be read at any time, and the serviceability can be improved.

[Brief description of drawings]

FIG. 1 is a block diagram showing the configuration of an embodiment.

FIG. 2 is a flowchart showing a diagnostic program.

FIG. 3 is a sectional view of a torque converter.

[Explanation of symbols]

 1 engine 2 automatic transmission 3 torque converter 4 oil pan 4a automatic transmission control valve 5 engine control unit (ECM) 6 engine rotation sensor 7 electronically controlled actuator 8 automatic transmission input shaft rotation sensor 9 vehicle speed sensor 10 diagnostic device 10a torque converter included Output rotation speed difference calculation unit 10b Deceleration calculation unit 10c Engine stall prevention unit 10d Abnormality determination unit 10e Memory 11 Warning device 12 Diagnostic information output device

Claims (6)

[Claims] 1. A failure diagnosis device for an automatic transmission including a torque converter having a lockup mechanism, comprising: input shaft speed detecting means for detecting an input shaft rotation speed of the torque converter; and an output shaft of the torque converter. An output shaft speed detecting means for detecting a rotating speed, and a speed difference for calculating a speed difference between the input shaft rotating speed detected by the input shaft speed detecting means and the output shaft rotating speed detected by the output shaft speed detecting means. Calculating means, deceleration detecting means for detecting deceleration of the vehicle, input shaft rotational speed detected by the input shaft speed detecting means is a predetermined value or less, and speed difference calculated by the speed difference calculating means Is less than or equal to a predetermined value and the deceleration detected by the deceleration detecting means is less than or equal to a predetermined value, it is determined that the automatic transmission fluid is lower than a specified amount. Failure diagnosis apparatus for an automatic transmission characterized by comprising an oil amount judging means. 2. The failure diagnosis device for an automatic transmission according to claim 1, wherein the input shaft speed detecting means detects a rotation speed of an engine directly connected to an input shaft of the torque converter. Failure diagnosis device for automatic transmission. 3. The failure diagnosis device for an automatic transmission according to claim 1, wherein the deceleration detection means has a vehicle speed detection means for detecting a traveling speed of the vehicle, and the vehicle speed detection means A failure diagnosis device for an automatic transmission, characterized in that a deceleration of the vehicle is calculated based on the detected traveling speed. 4. The failure diagnosis device for an automatic transmission according to claim 1, wherein the deceleration detection means detects an output shaft rotation speed of the automatic transmission. A failure diagnosis device for an automatic transmission, comprising: means for calculating the deceleration of the vehicle based on the output shaft rotation speed detected by the automatic transmission output shaft speed detection means. 5. The failure diagnosis device for an automatic transmission according to any one of claims 1 to 4, wherein a warning is issued when the oil amount determination means determines that the automatic transmission oil is lower than a specified amount. A failure diagnosis device for an automatic transmission, comprising: 6. The failure diagnosis device for an automatic transmission according to claim 1, wherein the storage means stores the determination result of the oil amount determination means, and the storage means stores the determination result. A failure diagnosis device for an automatic transmission, comprising: an output unit that outputs a determination result.