JPH04347052A - Gear change abnormality detecting device of automatic transmission - Google Patents

Abstract

PURPOSE:To provide a gear change abnormality detecting device of an automatic transmission which can carry out a rapid fail detection coping with various gearshift stages. CONSTITUTION:A gearshift stage detecting means 1 detects a gearshift stage from the input rotating speed and the car speed. A measuring means 2 measures the actual engaging time of a friction engaging device in a shifting time of a gearshift stage. On the other hand, the upper limit value of the engaging time of the friction engaging device is set beforehand according to each gearshift stage, and the engaging time measured by the above measuring means is compared with the upper limit value corresponding to the gearshift stage at that time. When the measured time is longer than the upper limit value, it is decided that the gear change is abnormal.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a device for detecting whether or not gear changes in an automatic transmission are being performed normally.

0002

2. Description of the Related Art Conventionally, automatic transmissions have been known which are equipped with a gear transmission mechanism and a plurality of frictional engagement devices, and which automatically change gears by selectively engaging these frictional engagement devices. There is. In this type of automatic transmission, in order to detect whether or not the gear shifting is being performed normally, there is a means for determining whether or not the gear shifting is abnormal, and a means for determining whether or not the gear shifting is abnormal, and a means for determining whether or not the gear shifting is abnormal. A shift control device has been proposed (Japanese Unexamined Patent Publication No. 188844/1983), which includes means for changing the shift pattern in the shift to a fail shift pattern in which the shift point is set to a low level exclusively for abnormal situations.

In the case of the above-mentioned transmission control device, the means for determining abnormality monitors the engine rotation speed, and determines transmission abnormality based on whether the time during which the engine rotation speed is lowered is longer than a preset value. ing. For example, if the time during which the engine speed is decreasing, that is, the shift time is longer than the set value, the line pressure supplied to the frictional engagement device may be lower than the reference value, or the frictional engagement device itself may be worn out. This means that an abnormality signal is output to notify the driver of the abnormality, and the gear shift pattern is switched to a lower side.

0004

By the way, the shift time, that is, the engagement time of the frictional engagement device differs depending on each gear stage. For example, the time required for shifting from the first gear to the second gear is different from the time required for shifting from the third gear to the fourth gear. However, if the set value is set to a constant value regardless of the gear as described above, this set value must be set to a value based on the longest shift time, and therefore, after a considerable number of abnormal gear shifts, Otherwise, abnormality detection may not be possible. As a result, the durability of the frictional engagement device may be impaired at the time the abnormality is detected.

SUMMARY OF THE INVENTION Accordingly, an object of the present invention is to provide a shift abnormality detection device for an automatic transmission capable of quickly detecting a failure corresponding to each gear stage.

[0006]

[Means for Solving the Problems] In order to achieve the above object, the present invention provides an automatic transmission that automatically switches gears by selectively engaging a frictional engagement device.
As shown in FIG. 5, a gear position detecting means for detecting or determining the gear position, a means for measuring the actual engagement time of the frictional engagement device at the time of changing the gear position, and a means for measuring the actual engagement time of the frictional engagement device when changing the gear position. If the engagement time measured by the above-mentioned measuring means is compared with the upper limit value corresponding to the gear position at that time and the upper limit value of the time is set in advance according to each gear position, if the measured time is longer than the upper limit value. and means for determining that the gear shift is abnormal.

As the gear position detection means, a sensor that directly detects the gear position may be provided, but the gear position can be determined from the ratio of the input rotation speed (engine rotation speed) and the output rotation speed (vehicle speed) of the automatic transmission. Alternatively, the gear stage may be determined based on the throttle opening degree and vehicle speed from a preset shift pattern.

The means for measuring the engagement time of the frictional engagement device may be, for example, by measuring the time during which the engine rotational speed decreases or increases during gear shifting, or by measuring the time when the output shaft torque changes. It may be measured by any other method.

Furthermore, in the case of an automatic transmission with four forward speeds, the means for setting the upper limit value of the engagement time can be used to shift from the first gear to the second gear, from the first gear to the third gear, and from the first gear to the third gear when upshifting. 1st
from speed to 4th speed, from 2nd speed to 3rd speed, from 2nd speed to 4th speed,
Six types of upper limit values are set, such as from 3rd gear to 4th gear, and even when downshifting, from 2nd gear to 1st gear, from 3rd gear to 2nd gear, from 3rd gear to 1st gear, and from 3rd gear to 1st gear. Six types of upper limit values are set, such as from 4th speed to 3rd speed, from 4th speed to 2nd speed, and from 4th speed to 1st speed. These upper limit values are preferably determined by multiplying the target engagement time at each gear by a constant coefficient or by adding a constant time.

The abnormality determining means outputs an abnormality signal when the time measured by the measuring means is longer than the upper limit value corresponding to the current gear detected by the gear detecting means. This signal may activate an alarm, increase line pressure, or change the shift pattern.

[0011] In the present invention, it is also possible to set not only the upper limit value but also the lower limit value and perform fail detection even when the shift time is too short. According to this, even if the line pressure is too high, it can be detected.

The fail detection of the present invention may be performed by notifying the driver directly during actual driving, or by storing the output signal of the abnormality determining means in a backup memory or the like, and using this data when diagnosing a vehicle failure. It may also be possible to analyze it as follows.

[0013]

DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 shows a system diagram of a vehicle equipped with a shift abnormality detection device according to the present invention. The output of the engine 1 is transmitted to a transmission mechanism 4 via a torque converter 3 of an automatic transmission 2, and the transmission mechanism 4 is further connected to a subsequent propeller shaft (not shown). The automatic transmission 2 includes an oil pump 5 driven by a torque converter 3, and oil discharged from the oil pump 5 is sent to a hydraulic control device 6. The hydraulic control device 6 controls the hydraulic pressure of various frictional engagement devices such as a speed change clutch and a brake built into the speed change mechanism 4 according to the driving state, oil temperature, and the like.

The engine 1 is provided with a throttle sensor 10 that detects the throttle opening, and the automatic transmission 2 includes an input shaft rotation sensor 11 that detects the rotation speed of the input shaft and an input shaft rotation sensor 11 that detects the rotation speed of the output shaft. A vehicle speed sensor 12 and an oil temperature sensor 13 that detects the temperature of hydraulic oil in the automatic transmission 2 are provided. In addition, near the driver's seat, there is a mode selection switch 14 that manually switches between an economy mode that emphasizes fuel efficiency and a power mode that emphasizes driving performance, an inhibitor switch 15 that commands the select lever position, and a warning dialog that alerts you to abnormal gear changes. A lamp 16, an indicator 17 for displaying the driving mode, and the like are provided.

[0015] The above sensors 10 to 13 and switch 14
, 15 are input to a controller 20 consisting of a microcomputer. The controller 20 compares input signals and setting data according to a predetermined program.
The solenoid 2 provided in the hydraulic control device 6 performs calculation processing.
A command signal is output to terminals 1 to 24. Among these, 21 is a line pressure control solenoid, 22 is a lockup solenoid, and 23 and 24 are speed change control solenoids. The controller 20 receives an input rotation speed NIN from an input shaft rotation sensor 11 and a vehicle speed sensor 12.
and the output rotational speed NOUT to the gear ratio (NIN/NOU
T ) is calculated, and the gear position is automatically detected from this gear ratio. In addition, in order to obtain a gear position corresponding to the output rotational speed NOUT and the throttle opening according to a predetermined shift pattern, the shift control solenoid 23,
It controls 24. Furthermore, the line pressure control solenoid 21 is controlled according to the running condition and the hydraulic oil temperature to control the line pressure to be suitable for the running condition.

Next, a method for detecting a shift abnormality according to the present invention will be explained based on FIGS. 2 and 3. Note that an example of an automatic transmission having four forward speeds will be described here. First, throttle opening, oil temperature, input rotation speed,
After inputting various signals such as an output rotational speed and a mode selection signal, it is determined whether or not a shift condition is satisfied (step 30). This determination can be made, for example, based on whether the gear position determined by the output rotational speed and the throttle opening is different from the actual gear position, according to a preset gear change pattern. When the shift condition is satisfied, a shift operation is performed (step 31), and the shift time, that is, the time from the start to the end of engagement of the frictional engagement device is measured (step 32). This shift time can be easily determined, for example, by measuring the time T during which the input rotational speed is changing as shown in FIG. Next, it is determined in steps 33 to 43 what gear position the above-mentioned shift operation is to be performed, and a shift limit time corresponding to each gear position is set (steps 44 to 55). The shift limit time is
As shown in Table 1, it is set according to each gear stage, and consists of an upper limit time and a lower limit time.

[0017]

[Table 1]

Next, the shift time is compared with the upper limit time (step 56), and if the shift time ≦ the upper limit time, then it is compared with the lower limit time (step 57), and the shift time ≧ the lower limit time. In this case, it means that normal gear shifting is being performed, so return as is. On the other hand, if shift time>upper limit time or shift time<lower limit time, it means that abnormal gear shifting is being performed, so write the engagement failure diagnosis code in the backup RAM etc. built into the controller 20. It is memorized (step 58), and the diagram lamp 16 is lit to instruct the driver that there is a gear shift abnormality (step 5).
9), Return.

When the diagnostic lamp 16 is turned on while the vehicle is running due to fail control as described above, the driver knows that some abnormality such as a drop in line pressure has occurred. As a result, the driver adjusts the throttle opening as low as possible, reducing the load on the frictional engagement device, suppressing slippage, and preventing a decrease in durability. Further, since the abnormality signal is stored in a backup RAM or the like, by analyzing the data stored in the RAM when diagnosing a fault in the vehicle, it is possible to easily discover in which state the abnormality in gear shift has occurred.

[0020]

[Effects of the Invention] As is clear from the above explanation, according to the present invention, a shift abnormality is determined by comparing the upper limit value corresponding to each gear stage with the actual engagement time. , it becomes possible to quickly detect failures corresponding to each gear stage, and has the effect of realizing safe driving.

[Brief explanation of the drawing]

FIG. 1 is an overall system diagram of a vehicle equipped with an automatic transmission according to the present invention.

FIG. 2 is a flowchart for detecting a shift abnormality.

FIG. 3 is a flowchart diagram connected to FIG. 2;

FIG. 4 is a diagram showing changes over time in input rotational speed during gear shifting.

FIG. 5 is a block diagram showing the configuration of a shift abnormality detection device according to the present invention.

[Explanation of symbols]

1 Engine 2 Automatic transmission 10
Throttle sensor 11
Input rotation speed sensor 12 Vehicle speed sensor

Claims (1)

[Claims] Claim 1. An automatic transmission that automatically switches gears by selectively engaging a frictional engagement device, comprising a gear detecting means for detecting or determining a gear, and a friction detecting means for detecting or determining a gear. means for measuring the actual engagement time of the engagement device; means for presetting the upper limit of the engagement time of the frictional engagement device according to each gear; and the engagement time measured by the measuring means. A shift abnormality detection device for an automatic transmission, comprising means for comparing the shift with an upper limit value corresponding to the gear position at that time and determining that the shift is abnormal if the measured time is longer than the upper limit value.