Daimlerchrysler Corporation

Chrysler Corporation

John M Prevost

Shean P Huff

Richard K Moote

Howard W Krausman

Yi Cheng

Mary Joyce

Gary L Seitz

Mark E Hope

William D Rotramel

Jerry Kennie

Zhong Li

Patrick T McCourt

Justin E DeWitte

A vehicle controller adjusts fuel delivered to an engine to compensate for an unknown fuel type being added to a fuel tank in a flexible fueled vehicle. The controller fuels a first set of engine cylinders according to first fueling scheme. For example, the controller fuels the first set assuming that E85 fuel was added to the fuel tank. The controller fuels a second set of engine cylinders according to a second fueling scheme. For example, the controller fuels the second set assuming that E0 fuel was added to the fuel tank. The controller continues to fuel the engine in this manner until an oxygen sensor becomes available. When the oxygen sensor becomes available, the vehicle controller may fuel the engine according to information from the oxygen sensor.

Engine operation on an unknown ethanol fuel blend

A method for checking the accuracy of an oxygen sensor based determination of the alcohol content of the fuel of a flexible fueled vehicle. Following the addition of fuel to the flexible fueled vehicle two alcohol concentration possibilities are calculated. The two alcohol concentration possibilities are then used to calculate thresholds for the determining if the oxygen sensor based determination falls within the thresholds. If the oxygen sensor based determination does not fall within the thresholds then action is taken to counteract an inaccurate determination of alcohol concentration.

Ethanol content rationality for a flexible fueled vehicle

A method is provided for monitoring the integrity of a fuel composition sensor in a flexible fueled vehicle. At ignition-on, the fuel composition sensor is tested for electrical and rationality viability. After ignition-on, the fuel composition is periodically, non-intrusively, tested for potential rationality errors. Should the non-intrusive testing indicate that a potential error exists, the fuel composition sensor is intrusively tested for rationality errors. If the intrusive test detects that the fuel composition sensor is malfunctioning, the engine control system converts to a limp-in mode and sets the engine operating parameters based on feedback from an exhaust gas oxygen sensor system.

Fuel composition sensor rationality test

A method according to the present invention controls engine roughness by varying the ethanol content in a fuel mixture of a flexible fuel vehicle. Initially, a trigger threshold and fix threshold are established based on engine speed and manifold pressure. The fix threshold is less than the trigger threshold. A first ethanol amount is delivered to the fuel mixture if a first measured roughness is greater than the trigger threshold. A second measured engine roughness is determined after delivering the first ethanol amount. The delivery of the first ethanol amount is stopped if the second measured roughness is greater than the trigger threshold. A second ethanol amount is delivered if the second measured roughness is less than the trigger threshold but greater than the fix threshold. A third measured roughness is then determined. Delivery of the second ethanol amount is stopped if the third measured roughness is greater than the trigger threshold. The roughness is measured and ethanol delivery modified accordingly so long as the third measured roughness is less than the trigger threshold and greater than the fix threshold.

Ethanol content learning based on engine roughness

The present invention is directed towards a method of controlling combustion parameters of an internal combustion engine prior to oxygen sensor feedback availability for a flexible fueled vehicle. If the vehicle has previously been running on ethanol or has been using ethanol in the recent past, a first strategy is employed which basis engine fueling on the minimum of a theoretically appropriate fueling value and a theoretically calculated value. If the vehicle has not previously been running on ethanol or has not been using ethanol in the recent past, a second strategy is employed which basis engine fueling on the minimum of the theoretically appropriate fueling value, the theoretically calculated value and a roughness calculated value.

Method of determining the composition of fuel in a flexible fueled

An apparatus and method are provided for detecting cylinder misfires in an internal combustion engine of a motor vehicle which provides a good signal to noise ratio and is capable of distinguishing from noise related events such as misfire induced bobble and harsh clutching maneuvers. Crankshaft rotation is sensed and crankshaft velocities are measured for each cylinder. Changes in angular velocity are determined and correspond to each of a plurality of cylinder firing events. With a first averaging filter, angular velocity changes are sorted over a predetermined series of cylinder firings and the two middle angular velocity changes are averaged to provide an average change in velocity value. A deviation is determined between the change in angular velocity for a selected cylinder and the average change in velocity. With a second averaging filter, the deviations from the first averaging filter are sorted over a series of cylinder firings and the two middle most deviations are averaged to provide an average change of deviation thereof. A second deviation is determined between the change in the first deviation for a selected cylinder and the average deviation value. The second deviation is compared to a threshold value and a misfire event is determined for the selected cylinder based on the comparison. Any number of two or more cascade connected average filters may be employed.

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Spring Arbor, MI, United States of America

John M Prevost