Internal-combustion engines – Engine speed regulator – Open loop condition responsive
Reexamination Certificate
1999-08-23
2001-01-16
Kwon, John (Department: 3747)
Internal-combustion engines
Engine speed regulator
Open loop condition responsive
C123S339150
Reexamination Certificate
active
06173697
ABSTRACT:
BACKGROUND OF THE INVENTION
This invention relates to improvements in a fail-safe system in an electronic control system for an engine, and more particularly to the fail-safe system in which a fail-safe condition can be suitably accomplished.
Most automotive vehicles are equipped with an electronic control system which electronically controls an engine power output system including an internal combustion engine. The engine includes a device for causing the engine to generate an engine power output, for example, one relating to fuel injection control (such as an electronically controlled throttle device, or a fuel injector valve), one relating to spark timing control (such as s spark plug), and one relating to idling engine speed control (such as an auxiliary air control valve).
The electronic control system is usually provided with a fail-safe system which is adapted to put the engine power output causing device into a fail-safe condition or mode when it is detected that an abnormality or trouble arises in the engine power output causing device. In such the fail-safe condition, for example, the engine power output is lowered by fixing the opening degree of a throttle valve of the electronically controlled throttle device to a certain small level, by minimizing a quantity of fuel injected from the fuel injector valve, or by retarding the spark timing of the spark.
SUMMARY OF THE INVENTION
In the above conventional fail-safe system, releasing the fail-safe condition for the engine power output causing device is accomplished as occasion demands, for example, after the trouble has been solved upon repairing the engine power output causing device in a repair shop. It is desired that the fail-safe condition cannot be released in case that the fail-safe condition is required in order to achieve a safe control for the engine.
It is, therefore, an object of the present invention to provide an improved fail-safe system for an engine of a vehicle, which can improve safety in conventional fail-safe systems.
Another object of the present invention is to provide an improved fail-safe system for an engine of a vehicle, which can release a fail-safe condition for an electronically controlled mechanism, in such a suitable manner as to improve safety in engine operational control.
A further object of the present invention is to provide an improved fail-safe system for an engine of a vehicle, which can suitably release a fail-safe condition for an electrically controlled engine power output causing device (for example, an electronically controlled throttle device) only when no trouble will arise.
An aspect of the present invention resides in a fail-safe system for an engine of a vehicle. The fail-safe system comprises a device for causing the engine to generate an engine power output. A detector is provided to detect an operational condition of the causing device so as to generate a detection signal representative of the operational condition. Additionally, a control unit is provided to be programmed to carry out (a) judging that an abnormality arises in the causing device, in accordance with the detection signal from the operational condition detector, so as to make a first judgment result, (b) putting the causing device into a fail-safe condition upon the first judgement result being made, (c) judging that a command for releasing the fail-safe condition is provided, so as to make a second judgment result, (d) judging that the vehicle is in a stopping condition, so as to make a third judgment result, and (e) releasing the fail-safe condition for the causing device upon both the second and third judgment results being made.
Another aspect of the present invention resides in a method of controlling a fail-safe system for an engine of a vehicle. The fail-safe system includes a device for causing the engine to generate an engine power output, and a detector for detecting an operational condition of the causing device so as to generate a detection signal representative of the operational condition. The method comprises (a) judging that an abnormality arises in the causing device, in accordance with the detection signal from the operational condition detector, so as to make a first judgment result, (b) putting the causing device into a fail-safe condition upon the first judgement result being made, (c) judging that a command for releasing the fail-safe condition is provided, so as to make a second judgment result, (d) judging that the vehicle is in a stopping condition, so as to make a third judgment result, and (e) releasing the fail-safe condition for the causing device upon both the second and third judgment results being made.
REFERENCES:
patent: 5154150 (1992-10-01), Vieira
patent: 5163402 (1992-11-01), Taguchi et al.
patent: 5755201 (1998-05-01), Knoss et al.
patent: 5775293 (1998-07-01), Kresse
patent: 5823164 (1998-10-01), Seki et al.
patent: 6047679 (2000-04-01), Matsumoto et al.
patent: 6065448 (2000-05-01), Hatton et al.
Foley & Lardner
Kwon John
Nissan Motor Co,. Ltd.
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