Abstract: An acceleration enrichment pulse generation circuit which is utilized to generate enrichment pulses, the frequency and duration of which are controlled in accordance with the rate of change of throttle position sensed by a linear potentiometer, the angle function of the throttle position and the engine coolant temperature. The circuit also includes a closed throttle signal generator and a wide open throttle signal generator. The control circuit includes a differentiator which controls the output frequency of a voltage controlled oscillator, the voltage level of the output from the differentiator being indicative of the rate of change of the throttle position. This frequency output signal is fed to a single shot multivibrator to control the duty cycle of the single shot multi-vibrator and thus the duty cycle of the acceleration enrichment pulses being fed to the fuel injectors. The operation of the single shot multivibrator is varied by the throttle angular position function and the engine coolant temperature.

Abstract: A single point fuel injection system for an internal combustion engine including a throttle body having first and second air intake throats corresponding to first and second intake manifold planes of the engine, the air flow through each throat being controlled by throttle plates positioned within each throat. The throttle body further includes a fuel accumulating bowl which is integrally formed with the throttle body, the bowl being enclosed by a diaphragm and cover member. Within the enclosure of the fuel bowl are positioned a pair of injectors which are adapted to inject pulsed portions of fuel through a sonic nozzle and into the air intake throat of the throttle body. The injection of pulses of fuel into the throat is timed in accordance with the sensing of the crankshaft reaching a position of 15.degree. before top dead center to enhance the distribution of fuel charge from cylinder to cylinder.

Abstract: A frequency modulated control circuit for an electronic fuel injection system to control the pulse-type injection of fuel at a single point of the fuel intake of an internal combustion engine in accordance with the derived mass air flow rate into the engine comprising a pressure sensor for sensing the manifold pressure of the internal combustion engine, and an engine speed sensor, both of which generate an analog signal which is multiplied by a multiplier circuit to provide a signal representative of the mass air flow to the engine. The multiplier circuit includes a separate control input for varying the output signal level of the multiplier circuit by a preselected factor determined by the final output of the control circuit. The output of the multiplier circuit is fed to a voltage controlled oscillator to produce an output signal taking the form of a pulse train, the frequency of which varies with the amplitude of the mass air flow signal.