Gm Global Technolgoy Operations, Inc.

Dah-Lain Tang

Man-Feng Chang

Marek T Wlodarczyk

Myrna C Sultan

Using a plurality of engine position reference pulses for each cylinder event, several reference periods for each cylinder event are defined and the engine speed can be accurately predicted for the current reference period and for future reference periods using position data from only the current combustion interval. For speed control the start of injection and start of spark dwell are computed based on predicted engine speeds for periods after those functions are started. Adaptive prediction gains are used to update the prediction algorithms to reflect the current engine operation conditions and minimize prediction error.

Engine speed prediction method for engine control

A delta model is used to calculate a predicted manifold absolute pressure MAP for a future period and the air mass induced in each cylinder is calculated from such a predicted value and used to determine the correct amount of fuel to inject at that period. Several reference pulses generated for each crankshaft revolution establish one or more sets of equally spaced points at which measurements are made of the parameters MAP, throttle position, exhaust gas recirculation value and idle air control. A base value of MAP is calculated, trends of changes in the parameters are calculated for each set of points, and weighted values of the trends are summed with the base value to predict a value of MAP. Alternatively, mass air flow MAF is measured as well as the other parameters and mass air per cylinder MAC is calculated. Then a base value of MAC is calculated, trends of changes in the parameters are calculated for each set of points, and weighted values of the trends are summed with the base value to predict a value of mass air induced into a cylinder.

Prediction method for engine mass air flow per cylinder

In engine fuel control applications in which a fuel command is issued to control at least a pair of fuel injectors, fuel command compensation is provided to stabilize fuel control from injection to injection while retaining fuel delivery accuracy. Fuel control performance over a control period is modelled, and the model stabilized through modern control techniques. Non-linear compensation is applied to reduce any residual fueling error, and both synchronous and asynchronous transient compensation are provided.

Electronic fuel injection control

Misfire is detected in an internal combustion engine during its starting mode by analyzing the engine speed profile. Average speed is determined for 60.degree. increments of crankshaft rotation. If an increment midway between top dead center positions has a higher speed than the previous increment and a higher speed than cranking speed, combustion occurred, otherwise a misfire occurred. When misfires are detected for a particular cylinder the calculated fuel allotment for that cylinder is reduced in accordance with the number of consecutive misfires for that cylinder.

Method for detecting engine misfire and for fuel control

A microprocessor based electronic spark control for an internal combustion engine is programmed to determine spark time using a prediction of engine speed during the spark period in which the next spark should occur and to make the calculations immediately prior to that period. The prediction is based upon the most recent speed information including a reference period value just prior to the next spark period. Reference pulses produced from a crankshaft driven transducer determine the measured reference periods and preferably comprise a plurality of pulses per spark event. One reference period is chosen as a base period and a weighted difference of recent periods is used to adjust the base to predict the spark period. The spark period or the corresponding engine speed is used in calculating the spark angle and the conversion to spark time. A hardware interrupt to the microprocessor causes the calculations to be made when the reference pulse nearest the next spark occurs.

Predictive spark timing method

A fiber optic detector head senses a light reflective or transmissive pattern on an encoder disk rotated by an engine shaft. The pattern results in three different light levels which are translated by a detector into an electrical pulse train having three different voltages. Patterns encoded into the single pulse train are decoded by a microprocessor to provide specific engine cylinder or cylinder pair position information even within the first spark firing period as well as engine speed information.

Optical fast synchronization shaft position and speed sensor

A fiber optic detector head senses a light reflective or transmissive pattern on an encoder disk rotated by an engine shaft. The pattern results in four different light levels which are translated by a detector into an electrical pulse train having four different voltages including a reference or background voltage. One light level is reserved for an index mark, another level for cylinder position marks and still another level for finer measurement of position and speed between the cylinder marks. Patterns encoded into the single pulse train are decoded by a microprocessor to provide specific engine cylinder position information as well as engine speed information.

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Canton, MI, United States of America

Dah-Lain Tang