Internal-combustion engines – Engine speed regulator – Open loop condition responsive
Reexamination Certificate
1999-08-27
2001-01-30
Solis, Erick (Department: 3747)
Internal-combustion engines
Engine speed regulator
Open loop condition responsive
C123S397000, C123S399000
Reexamination Certificate
active
06178947
ABSTRACT:
BACKGROUND OF THE INVENTION
Field of the Invention
The present invention relates to a computer-controlled internal combustion engine equipped with an electronically-controlled throttle system capable of electronically controlling the opening of the throttle valve, and more specifically to techniques for executing a fail-safe control routine in presence of a failure or an abnormality in a throttle position sensor located on the throttle body of an electronically-controlled throttle system and/or in an accelerator position sensor monitoring the amount of depression of an accelerator pedal.
There are two typical types of electronically-controlled throttle systems, one being a so-called half-electronically-controlled throttle system and a so-called full-electronically-controlled throttle system. The former half-electronically-controlled throttle system has a manually-wire-operated throttle valve as well as an electronically-controlled throttle valve which is commanded by an electronic engine control unit (ECU) or an electronic control module (ECM).
Usually, the electronically-controlled throttle valve is operated arbitrarily in response to an instruction of the ECU, based on engine/vehicle operating conditions, such as the amount of depression of an accelerator pedal or the like. In the presence of a failure either elsewhere in the ECU or within the sensor systems (such as, shorted/opened sensor input signals), the throttle control system switches from the full-electronically-controlled throttle system to the manually-wire-operated throttle system, so that the opening of the throttle valve is manually adjusted depending on the accelerator pedal travel. One such half-electronically-controlled throttle system has been disclosed in Japanese Patent Provisional Publication No. 7-180570.
Later models of full-electronically-controlled throttle systems utilize input informational signal data from two accelerator position sensors and two throttle position sensors. Generally, the ECU uses or selects a lower one of the sensor signals from the two accelerator position sensors byway of a so-called select-LOW process.
With respect to the throttle-opening indicative data, the ECU uses an input signal from a main throttle position sensor out of the two throttle position sensors, or selects a higher one of the sensor signals from the two throttle position sensors by way of a so-called select-HIGH process. If the failure occurs in either one of the two throttle position sensors of the duplex throttle-position sensor system, the throttle control system ordinarily de-activates the throttle actuator, so as to hold the opening of the electronically-controlled throttle valve at a predetermined “default” opening or a predetermined “fail-safe” opening, thereby putting the engine into its limp-home mode (or limp-in mode). The limp-home mode allows the engine/vehicle to be run/driven but with greatly reduced performance, (for example, the vehicle can limp in at a maximum speed of 40 Km/h). It is so inconvenient.
SUMMARY OF THE INVENTION
In case of a detected defective throttle-position sensor, it is rational and desirable to properly control the opening of an electronically-controlled throttle valve, using the input information signal from the other sensor (e.g., the other throttle position sensor in a duplex throttle-position sensor system). Furthermore, if the other throttle position sensor fails or operates abnormally, it is desirable to substitute a default opening (a fail-safe opening) for the second failed sensor. Accordingly, it is an object of the invention to provide an integrated engine control system which is capable of assuring a high-quality, reliable internal combustion engine with an electronically-controlled throttle system, by at least a duplex fail-safe system despite the presence of throttle-position sensor failures or faults.
It is another object of the invention to provide an integrated engine control system which is capable of assuring a high-quality, reliable internal combustion engine with an electronically-controlled throttle system, by at least a duplex fail-safe system despite the presence of accelerator-position sensor failures or faults.
It is a still further object of the invention to provide an integrated engine control system which is capable of assuring a high-quality, reliable internal combustion engine with an electronically-controlled throttle system, by at least a duplex fail-safe system for a throttle-position sensor system despite the presence of a throttle-position sensor failure or fault and by at least a duplex fail-safe system for an accelerator-position sensor system despite the presence of an accelerator-position sensor failure or fault.
In order to accomplish the aforementioned and other objects of the present invention, a control apparatus for an internal combustion engine with an electronically-controlled throttle system having a throttle valve disposed in an induction system and an actuator operating the throttle valve so that an opening of the throttle valve is adjusted to a desired opening, comprises a duplex throttle-position sensor system having two throttle position sensors each detecting the opening of the throttle valve, a vehicle-deceleration sensor detecting a decelerating condition of the engine and generating a deceleration indicative signal, and a fail-safe system configured to be electronically connected to the two throttle position sensors and the vehicle-deceleration sensor for responding to a failure in at least one of the two throttle position sensors for failsafe purposes, the fail-safe system comprising a first failsafe section which controls the opening of the throttle valve by a sensor signal value from an unfailed throttle position sensor of the two throttle position sensors at a single throttle-position sensor failure mode where one of the two throttle position sensors is failed, to initiate a first failsafe mode, a second failsafe section which inhibits the first failsafe mode in response to the deceleration indicative signal from the vehicle-deceleration sensor during the first failsafe mode and holds the throttle valve at a predetermined default opening, to initiate a second failsafe mode, and a third failsafe section which detects if the sensor signal value from the unfailed throttle position sensor is within a predetermined sensor-abnormality diagnostic criterion range during the second failsafe mode, and unconditionally continues to hold the opening of the throttle valve at the predetermined default opening when the sensor signal value from the unfailed throttle position sensor is out of the predetermined sensor-abnormality diagnostic criterion range.
According to another aspect of the invention, a control apparatus for an internal combustion engine with an electronically-controlled throttle system having a throttle valve disposed in an induction system and an actuator operating the throttle valve so that an opening of the throttle valve is adjusted to a desired opening, comprises a duplex throttle-position sensor system having two throttle position sensors each detecting the opening of the throttle valve, a duplex accelerator-position sensor system having two accelerator position sensors each detecting an amount of depression of an accelerator pedal, a vehicle-deceleration sensor detecting a decelerating condition of the engine and generating a deceleration indicative signal, and a fail-safe system configured to be electronically connected to the two throttle position sensors, the two accelerator position sensors and the vehicled-deceleration sensor for responding to a failure in at least one of the two throttle position sensors and the two accelerator position sensors for failsafe purposes, the fail-safe system comprising a first failsafe section which feedback-controls the opening of the throttle valve by a sensor signal value from an unfailed throttle position sensor of the two throttle position sensors at a single throttle-position sensor failure mode where one of the two throttle position sensors is failed, to initiate a fi
Hyoudou Hideki
Iriyama Masahiro
Machida Kenichi
Mizuguchi Masaru
Nozaki Mikio
Foley & Lardner
Solis Erick
Unisia Jecs Corporation
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