Closed-loop idle speed control system for fuel-injected engines using pulse width modulation

摘要: A closed loop idle speed controller for a fuel injection system operates to control an air valve which controls passage bypassing the main flow. The is positioned by actuator whose output position controlled pressure operating against spring. pair of solenoid-operated on-off valves, one responds electrical signals representing engine speeds below reference direct and other above permit be withdrawn from returned its source. Each solenoid valves supplied pulse width modulator. engine-driven distributor provides pulses responsive are connected sample hold circuit. circuit d.c. voltage levels proportional rpm, modified with changes in coolant temperature, summing amplifiers compare produce error signals. Underspeed modulator supply overspeed return valve. Certain auxiliary circuits provide operation during starting, hot starts, throttle operation, or deceleration manual transmission car.