An engine may include an electronically operated throttle to regulate air flow into the engine. The throttle may open for greater driver demand torques and close for lesser driver demand torques. The throttle's position may be monitored and corrected via one or more throttle position sensors. It may be possible for one or more throttle position sensors to exhibit degradation. The degradation may make it more difficult to achieve a desired level of throttle control performance. One way to control the throttle in the presence of perceived throttle sensor degradation is to command the throttle to a substantially closed position (e.g., open less than five percent of full range) or to limit an opening amount of the throttle. However, limiting a throttle to a small opening amount may make it more difficult for a driver of the vehicle to reach a service location.
The inventors herein have recognized the above-mentioned disadvantages and have developed a method for operating an engine via a controller in combination with a throttle, comprising: commanding the throttle to a position via the controller in response to an indication of throttle degradation; and activating an electric compressor via the controller in response to the indication of throttle degradation.
By activating an electric compressor and commanding an engine throttle open, it may be possible to provide the technical result of controlling engine air flow in response to a driver demand torque in the presence of throttle degradation. In particular, speed of the electric compressor may be adjusted to follow a choked flow line of a compressor map for the electric compressor so that engine air flow may be controlled while throttle operation may be degraded.
The present description may provide several advantages. Specifically, the approach may provide for improved vehicle drivability during conditions of throttle degradation. Further, the approach may provide for a larger engine operating range during conditions of throttle degradation. Further still, the approach may include additional mitigating actions responsive to electric compressor and throttle degradation.
The above advantages and other advantages, and features of the present description will be readily apparent from the following Detailed Description when taken alone or in connection with the accompanying drawings.
It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.
USPTO Backgrounds
USPTO Backgrounds