JPH0526341A - Load sensor fault detection device for driving load sensitive control device - Google Patents

Abstract

PURPOSE:To provide data for making proper corrections on faults by converting respective signals from throttle opening and intake air sensors to common quantities of driving load state to determine the difference between the two values to detect faults in the two sensors. CONSTITUTION:A throttle opening sensor 7 which detects the opening of a throttle valve in an engine 2 and an intake air sensor 8 which detects the quantity of intake air Q for the engine 2 are provided. A controller 6 first loads in the said opening of a throttle valve Q to convert it to an engine output torque. The controller 6 then loads in the quantity of intake air Q to convert it to an engine output torque. The difference between the two converted torques is determined and if the value is below the set value, it can be judged that either of the two sensors 7, 8 is faulty. In such a case, proper action such as changing the speed change stage to the third speed stage which has a wide practical range and fixing the line pressure to the upper limit set for the safe side is taken to correct the fault.

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 an abnormality in a load sensor of a drive load responsive control device such as a shift control device for an automatic transmission.

[0002]

2. Description of the Related Art A shift control device for an automatic transmission uses a drive load (transmission input torque) of an engine, which is a source of power to be transmitted by the transmission, as one of the main control factors and determines a suitable shift stage The hydraulic pressure (line pressure) of the friction element (clutch or brake) that performs the selection operation of the shift stage in the transmission is determined.

By the way, the drive load of the engine can be generally represented by the throttle opening or the engine intake air amount. As a shift control device having the throttle opening as a control factor, "RE4R01A type automatic transmission" issued by Nissan Motor Co., Ltd. There is one described in "Maintenance Manual", and a gear shift control device having an engine intake amount as a control factor is described in JP-A-57-97944 and JP-A-62-127549.

On the other hand, today, when the line pressure control is performed according to the throttle opening degree, it is difficult for the throttle opening degree to reflect the change in the engine output torque (driving load) according to the temperature change and the atmospheric pressure change. Is likely to be inaccurate,
There is also an idea that it is better to perform the line pressure control according to the engine intake air amount and to determine the shift speed according to the throttle opening degree because it is not preferable in terms of shift shock.

[0005]

However, even in the control device having two drive load signals based on this idea, one drive load signal, that is, the throttle opening signal or the engine intake air amount signal detects them. If the sensor disappears due to an abnormality, the control becomes useless and some abnormality processing is required. Therefore, it is an object of the present invention to provide a device for detecting an abnormality in the load sensor of this type of drive load responsive control device.

[0006]

To this end, the present invention, as shown in the concept of FIG. 1, controls signals from a throttle opening sensor and an intake air amount sensor which detect at least a throttle opening and an engine intake air amount, respectively. In the input device, first and second conversion means for converting signals from the throttle opening sensor and the intake air amount sensor into state quantities representing a common driving load, and subtraction means for obtaining a difference between the two state quantities. An abnormality determining means for determining that the throttle opening sensor or the intake air amount sensor is abnormal when the difference is equal to or more than a set value is provided.

[0007]

The control device performs predetermined control by using signals from at least the throttle opening sensor and the intake air amount sensor as control inputs. The first and second conversion means convert the signals from these sensors into a common drive load state quantity, and the subtraction means obtains the difference between these state quantities. When the difference is equal to or larger than the set value, the abnormality control means can determine that one of the two sensors is abnormal and can detect the abnormality, and can provide the material for the abnormality countermeasure.

[0008]

Embodiments of the present invention will now be described in detail with reference to the drawings. FIG. 2 shows an application example of the present invention to the automatic transmission 1. Reference numeral 2 denotes an engine for generating power to be transmitted by the transmission 1, and these are drive-coupled in tandem with the engine 1 as a front stage.

The automatic transmission 1 incorporates a power transmission gear train (not shown) and friction elements (clutch and brake) for selecting a transmission path (gear stage) in the gear train, and selectively hydraulically operates these friction elements. The (shift control) is performed by turning ON / OFF the shift solenoid 4 in the control valve 3, and the operating hydraulic pressure (line pressure) of the friction element is regulated by the duty control of the line pressure solenoid 5 in the control valve 3.

The solenoids 4 and 5 are controlled by a shift control controller 6, which can be a microcomputer, and this controller uses a signal from a throttle opening sensor 7 for detecting the throttle opening TH of the engine 2 and the engine. A signal from the intake air amount sensor 8 that detects the intake air amount Q and a signal from the vehicle speed sensor 9 that detects the vehicle speed V are input.

The controller 6 performs the following shift control and line pressure control based on these input information. That is, from the combination of the throttle opening TH detected by the sensors 7 and 9 and the vehicle speed V, the gear stage most suitable for the current driving state is determined. Then, the shift solenoid 4 is selectively turned on so that the transmission 1 is at this shift stage, and the corresponding friction element is hydraulically operated by the control valve 3. On the other hand, the controller 6 calculates a suitable value of the line pressure, which is the working oil pressure of the friction element, from the intake air amount Q detected by the sensor 8, and duty-controls the solenoid 5 so that the line pressure becomes the suitable value.

The above is the normal shift control and line pressure control. The controller 6 executes the program of FIG. 3 to detect an abnormality in the throttle opening sensor 7 and the intake air amount sensor 8 which are load sensors. In this program, first, the throttle opening TH detected by the sensor 7 is read, and then the engine output torque (transmission input torque)
Calculate by converting T (TH). Next, the intake air amount Q detected by the sensor 8 is read, and the engine output torque (transmission input torque) T (Q) is converted from this and obtained. In this example, the engine output torque (transmission input torque) is used as the common drive load converted from the throttle opening and the intake air amount as described above, but other state quantities representing the drive load, such as the throttle opening and Needless to say, the target line pressure according to the intake air amount may be used.

Next, the converted torques T (TH) and T
It is checked whether the absolute value of the difference between (Q) | T (TH) -T (Q) | is greater than or equal to the set value ΔT.
The abnormality is detected as one of 9 is abnormal. Note that the controller 6 performs an abnormality process because the control becomes unusable at the time of this abnormality, but as the abnormality process, the shift speed is set to the third speed (gear ratio 1), which has the widest practical range, and at the same time, the line pressure is reduced. It is conceivable that the pressure is fixed to the upper limit value of the pressure regulation on the safe side, or that the gear is controlled as it is according to the intake air amount.

FIG. 4 shows the torque conversion value T from the throttle opening.
An example of a time-series change in the torque conversion value T (Q) from (TH) and the intake air amount is illustrated, and in this case, the time t _{1 and} subsequent times are considered as abnormalities of the load sensors 7 and 9 when applying the above program.

[0015]

As described above, according to the present invention, the signals from the throttle opening sensor 7 and the intake air amount sensor 8 are converted into the common driving load state quantity, and the abnormality of both sensors is detected from the difference between the two. It is possible to provide a material for performing an appropriate process at the time of an abnormality, and prevent control from being spoiled.

[Brief description of drawings]

FIG. 1 is a conceptual diagram of a load sensor abnormality detection device according to the present invention.

FIG. 2 is a hardware configuration diagram showing an embodiment of the device of the present invention.

FIG. 3 is a flowchart showing a controller abnormality detection program in the example.

FIG. 4 is a time series change time chart regarding a torque conversion value of a sensor output when a load sensor is abnormal.

[Explanation of symbols]

 1 Automatic Transmission 2 Engine 3 Control Valve 4 Shift Solenoid 5 Line Pressure Solenoid 6 Shift Control Controller 7 Throttle Opening Sensor 8 Intake Air Volume Sensor 9 Vehicle Speed Sensor

Claims (1)

Claim: What is claimed is: 1. A device using signals from a throttle opening sensor and an intake air amount sensor for detecting at least a throttle opening and an engine intake air amount, respectively, as a control input,
First and second conversion means for converting the signals from the throttle opening sensor and the intake air amount sensor into state quantities representing a common driving load, subtraction means for obtaining the difference between the two state quantities, and this difference is greater than a set value. The load sensor abnormality detection device for a drive load response type control device, comprising: an abnormality determination means for determining that the abnormality is a throttle opening sensor or an intake air amount sensor.