JPH05215229A - Automatic transmission control device - Google Patents

Abstract

PURPOSE:To detect not only failures of a sensor and a gear transmission mechanism but also failure of a hydraulic power transmission, by structuring a control device so as to make decision of failures when the relation between input side rotation speed and output side rotation speed of the hydraulic power transmission reaches a range which is theoretically impossible. CONSTITUTION:A control device is equipped with an engine rotation speed detecting means 1, an output shaft rotation speed detecting means 2 and a conversion stage detecting means 3 for a gear transmission mechanism, and a hydraulic power transmission output side rotation speed calculating means 4 which calculates the rotation speed on the output side of the hydraulic power transmission according to the signals from the output shaft rotation speed detecting means 2 and the conversion stage detecting means 3. Combination of the engine rotation speed detected by the engine rotation speed detecting means 1 and the hydraulic power transmission output side rotation speed calculated by the hydraulic power transmission output side rotation speed calculating means 4 is decided whether it is possible or not from the viewpoint of performance of the hydraulic power transmission and that of an engine, and in the case of being an impossible combination from the viewpoint of performance, it is decided to be a failure by a failure deciding means 5.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an automatic transmission.

[0002]

2. Description of the Related Art As a conventional control device for an automatic transmission, there is one disclosed in Japanese Patent Application Laid-Open No. 1-172663. The automatic transmission control device shown therein is provided with a transmission input rotation sensor and a transmission output rotation sensor, calculates the gear ratio of the gear transmission mechanism of the transmission based on signals from both sensors, and When the calculated gear ratio is different from the regular gear ratio, it is determined that the gear transmission mechanism is out of order.

[0003]

However, in such a conventional automatic transmission control device, when a failure occurs in the torque converter arranged on the input side of the gear transmission, it is detected. There is a problem that you cannot do it. The present invention aims to solve such problems.

[0004]

The present invention solves the above problems by determining an abnormality from a combination of input and output rotational speeds of a fluid transmission. That is, the control device for an automatic transmission according to the present invention comprises an engine rotation speed detection means for detecting the rotation speed of the engine, an output shaft rotation speed detection means for detecting the rotation speed of the output shaft of the gear transmission mechanism, and a gear transmission mechanism. And a fluid transmission device output side rotation speed calculation means for calculating the rotation speed of the fluid transmission device output side based on signals from the output shaft rotation speed detection means and the transmission speed detection means. A combination of the engine rotation speed detected by the engine rotation speed detection means and the output side rotation speed of the fluid transmission device calculated by the fluid transmission device output side rotation speed calculation means is possible in terms of the performance of the fluid transmission device and the engine. If the combination is not possible in terms of performance, it is determined to be a failure.

[0005]

The relationship between the input rotation speed and the output rotation speed of the fluid transmission is limited to theoretically possible combinations depending on the performance of the fluid transmission itself and the performance of the engine. That is, for example, in a stall state in which the output side of the fluid transmission is fixed, the input rotation speed cannot exceed a predetermined value determined by the performance of the engine and the performance of the fluid transmission itself. Similarly, the theoretically allowable range of the input rotation speed is determined according to each value of the output rotation speed of the fluid transmission. Such an input / output relationship is shown as an example in FIG. The hatched area is a theoretically impossible combination area of the input rotation speed and the output rotation speed. If the relationship between the input rotation speed and the output rotation speed of the fluid transmission falls within the hatched area in FIG. 3, it is determined that the fluid transmission has failed, the gear transmission mechanism has failed, or the rotation speed detection means has failed. To be done.

[0006]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS As shown in FIG. 2, an automatic transmission 10 has a torque converter 12 (fluid transmission) and a gear transmission mechanism 14. The driving force from the engine 16 is input to the gear shift mechanism 14 via the torque converter 12. The rotation speed of the engine 16 is detected by an engine rotation speed sensor 18 (engine rotation speed detection means). The rotation speed detected by this is the same as the input rotation speed of the torque converter 12. The rotation speed of the output shaft of the gear transmission 14 is the output shaft rotation speed sensor 20.
(Output shaft rotation speed detecting means). Engine rotation speed sensor 18 and output shaft rotation speed sensor 20
The signal from is input to the control unit 22. The control unit 22 outputs a signal instructing the gear stage of the gear shift mechanism 14. Regarding detection of a failure, control is performed according to the control flow shown in FIG. First, it is determined whether or not a predetermined time has passed since the shift was performed (step 102). This predetermined time is set to be longer than the time required for shifting. If the predetermined time has elapsed, it is determined whether the select lever is in N, P or R (step 104). If none of N, P, and R, read the shift speed (see 10
5) The input rotation speed X of the gear shift mechanism is calculated from the current gear ratio G of the gear and the rotation speed S detected by the output shaft rotation speed sensor 20 (106). Then
The current engine speed read from the engine speed sensor 18 is set to Y, and it is determined whether or not the combination of X and Y is in the hatched area of FIG.
8). If it is in the hatched area, a warning signal is output (at 110), the gear transmission mechanism 14 is fixed to a predetermined gear state to prohibit shifting (at 112), and then the line pressure is set to the maximum state. (114). The above-mentioned failure determination is performed at regular intervals. By the control shown in FIG. 3, the torque converter 12, the gear transmission mechanism 14, and the output shaft rotation speed sensor 20 can be determined to be in failure. The hatched region shown in FIG. 4 is determined by the performance of the engine 16 and the performance of the torque converter 12, and is a theoretically impossible combination of the input rotation speed and the output rotation speed. For example, the output shaft rotation speed sensor 20
If the gear shift mechanism 14 enters the hatched area in the normal state, it is considered that the torque converter 12 is out of order. Further, for example, the output shaft rotation speed sensor 20
If a failure occurs and the output rotation speed lower than the actual output shaft rotation speed is detected, the combination at point a moves to point b and is detected as a theoretically impossible combination. Therefore, even if the output shaft rotation speed sensor 20 fails, it is detected as a failure. Further, when slippage occurs in a clutch or the like in the gear transmission 14, or when the stator one-way clutch of the torque converter 12 does not lock, the combination of the points c becomes the combination of the points d, and the failure is detected. It When a failure is detected, the driver is notified of this and
The control state is set so that the vehicle can continue running even in the case of a failure. That is, the gear shift mechanism 14
Is fixed to a predetermined gear to prevent shifting, and the line pressure is set to the highest level to prevent slippage of the clutch or the like. Note that step 10
5 constitutes the gear shift stage detecting means, step 106 constitutes the fluid transmission device output side rotational speed calculating means, and step 108 constitutes the failure determining means.

[0007]

As described above, according to the present invention, it is determined that a failure occurs when the relationship between the input and output rotational speeds of a fluid transmission device enters a theoretically impossible region. It is possible to detect not only the failure of the gear transmission mechanism but also the failure of the fluid transmission device.

[Brief description of drawings]

FIG. 1 is a diagram showing a relationship between components of the present invention.

FIG. 2 is a diagram showing an example of the present invention.

FIG. 3 is a diagram showing a control flow.

FIG. 4 is a diagram showing a relationship between an input rotation speed and an output rotation speed of the fluid transmission device.

[Explanation of symbols]

10 Automatic Transmission 12 Torque Converter (Fluid Transmission Device) 14 Gear Transmission Mechanism 16 Engine 18 Engine Rotation Speed Sensor (Engine Rotation Speed Detection Means) 20 Output Shaft Rotation Speed Sensor (Output Shaft Rotation Speed Detection Means) 22 Control Unit

Claims (1)

[Claims] 1. A control device for an automatic transmission, comprising a fluid transmission and a gear transmission mechanism, wherein the driving force of the engine is input to the gear transmission through the fluid transmission device. Engine rotation speed detecting means for detecting the rotation speed, output shaft rotation speed detecting means for detecting the rotation speed of the output shaft of the gear transmission mechanism, shift speed detecting means for detecting the shift speed of the gear transmission mechanism, and output shaft rotation A fluid transmission device output side rotation speed calculation means for calculating the rotation speed of the fluid transmission device output side based on signals from the speed detection means and the shift speed detection means, and an engine rotation speed and a fluid detected by the engine rotation speed detection means. A combination that can be combined with the output side rotation speed of the fluid transmission device calculated by the transmission output side rotation speed calculation means in terms of the performance of the fluid transmission device and the engine. Control device for an automatic transmission and having a a fault determining means for determining a failure in the case of combination is not possible in determining whether a combined performance.