The Bendix Corporation

John J Schira

Chun-Keung Leung

Edwin A Johnson

Alvin D Toelle

Jack R Phipps

A closed loop timing optimization control for an internal combustion engine closed about the instantaneous rotational velocity of the engine's crankshaft is disclosed herein. The optimization control computes from the instantaneous rotational velocity of the engine's crankshaft, a signal indicative of the angle at which the crankshaft has a maximum rotational velocity for the torque impulses imparted to the engine's crankshaft by the burning of an air/fuel mixture in each of the engine's combustion chambers and generates a timing correction signal for each of the engine's combustion chambers. The timing correction signals, applied to the engine timing control, modifies the time at which the ignition signal, injection signals or both are generated such that the rotational velocity of the engine's crankshaft has a maximum value at a predetermined angle for each torque impulse generated optimizing the conversion of the combustion energy to rotational torque.

Timing optimization control

Closed loop timing and fuel distribution controls for an internal combustion engine operative to control the timing and fuel delivery to each engine combustion chamber is disclosed herein. The closed loop timing and fuel distribution controls are closed about the instantaneous rotational velocity of the engine's output shaft and generate timing and fuel correction signals operative to modify the timing functions of the engine as well as the quantity of fuel delivered to each of the engine's combustion chambers. The control generates from the crankshaft's instantaneous rotational velocity a profile of each torque impulse imparted to the engine's output shaft and computes the phase angle signal indicative of the phase angle of each torque impulse to generate a timing correction signal indicative of the difference between the computed phase angle signal and a desired phase. The control further distribution computes the torque of each torque impulse and generates a torque correction signal indicative of the difference between the generated torque and average torque values. The two correction signals applied to an engine control modify the timing and fuel control signals being generated to cause the phase angle of the generated torque impulses to occur at the desired phase angle and the fuel delivery to each combustion chamber to be increased or decreased by an amount corresponding to the value of the torque correction signals. The torque corrected fuel delivery signals equalize the torque contribution of each combustion chamber to the total output torque of the engine.

Closed loop timing and fuel distribution controls

A digital electronic spark timing control for an internal combustion engine. Independent parameters such as engine speed and manifold pressure are measured and encoded as multibit digital words. A digital memory stores spark advance angle as a function of two independent parameters. The digital memory is addressed by the most significant bits of the multibit words to obtain coarse values of spark timing. Interpolation is performed on the coarse values according to the least significant bits of the digital words to produce the spark advance angle appropriate for the measured parameters. Means synchronized with engine position, i.e., top center, convert the spark advance angle to spark initiation signal.

Digital ignition timing controller

A closed loop exhaust gas recirculation (EGR) control system for an internal combustion engine having an intake system, an exhaust system, a throttle disposed within the intake system for controlling air flow therein, a conduit coupling the exhaust system to the intake system for supplying exhaust gas back to the intake system for controlling the generation and emission of oxides of nitrogen and for improving drivability and avoiding engine roughness. The EGR control system of the present invention includes a first memory pre-programmed with a look-up table of optimal EGR values indicative of EGR valve position or the like determined as a function of engine speed and throttle position and a second memory pre-programmed with the look-up table of optimal EGR values determined as a function of engine speed and absolute manifold pressure. The actual operating parameters of engine speed, throttle position and absolute manifold pressure are accurately sensed and stored as multi-bit binary numbers or words indicative thereof. The most significant bits (MSB) of the words are used to address the first and second memory while the least significant bits (LSB) of the words are used to perform a double linear interpolation of the accessed values to compute accurate first and second EGR values. The second EGR value is substracted from the first EGR value to determine a difference indicative of the current EGR valve error. A previously computed and stored EGR error value used to determine the last valve position adjustment is then substracted from the current EGR error value to determine the total change in error value required to correct the EGR valve position at the next adjustment. A fractional portion of the total change in EGR error value is then applied to the previously stored EGR error value to update same so as to avoid rapid or abrupt adjustments in the valve position so as to avoid engine roughness etc. The updated EGR error value is converted into a control signal which is used to adjust the position of the EGR valve at the next scheduled valve adjustment time so as to regulate EGR flow as desired.

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Westland, MI, United States of America

John J Schira