Abstract: A method and system for generating electronic fuel injection pulse waveforms to achieve an accurate air/fuel ratio control during transient conditions. Sensors are provided for sensing a plurality of engine parameters. An electronic engine controller is provided for performing a plurality of steps associated with the method. The method includes storing calibration data and sensing the engine parameters. A leading edge of the fuel pulse waveform is calculated based on the stored calibration data and the sensed engine parameters. The leading edge of the fuel pulse waveform is generated, thereby triggering an interrupt. Next, a trailing edge of the fuel pulse waveform is calculated based on current fuel mass requirements determined during the duration of the fuel pulse. The method concludes with the step of generating the trailing edge of the fuel pulse waveform.

Abstract: An electronic engine controller includes a central processing unit (CPU) which controls the operations of the controller and an analog-to-digital (A/D)converter chip which receives analog signals generated by sensors which transmit signals indicative of vehicle and engine operating parameters. The A/D converter chip automatically performs a conversion on certain signals indicative of critical engine operating parameters to generate corresponding digital values upon each engine revolution. These digital values are stored for retrieval by the CPU. Digital values corresponding to other signals are generated and transmitted upon request by the CPU. The A/D converter chip and the CPU are coupled by a serial link which operates under one of several protocols to transmit digital values from the A/D converter chip to the CPU.

Abstract: A method, for use with a vehicle including a multi-cylinder internal combustion engine having exhaust valves, for controlling the temperature of the exhaust valves during fuel cutoff modes of engine operation utilizing a bit pattern representation of the engine cylinders. The method includes cutting off the fuel delivered to the cylinders in an indexed cylinder firing pattern to vary which cylinders receive fuel, so as to maintain acceptable exhaust valve temperature levels. The method may also include operating the engine with a lean air/fuel ratio, so as to maintain acceptable catalytic converter temperature levels.