| 摘要 |
A method and apparatus for controlling the various functions of an internal combustion engine using a program-controlled microprocessor having a memory preprogrammed with various control laws and associated control schedules receives information concerning one or more engine-operating parameters such as manifold absolute pressure, throttle position, engine coolant temperature, air temperature, engine speed or period and the like. These parameters are sensed and then supplied to input circuits for signal conditioning and conversion into digital words usable by the microprocessor. The microprocessor system computes a digital command word indicative of a computer-commanded engine control operation and output circuitry responds to predetermined computer-generated commands and to the computed digital command words for converting them to corresponding pulse-width control signals for controlling such engine operations as fuel-injection ignition timing, proportional and/or on-off EGR control, or the like. The engine control system further includes an oxygen sensor feedback system for supplying signals indicative of the quantity of oxygen in the exhaust system of the engine back to the microprocessor for control purposes. In particular this disclosure relates to an oxygen sensor condition circuit which generates not only the bilevel output signals indicating the quality of oxygen in the exhaust system, but also generates an oxygen sensor inhibit signal which may be used in a control system to effectively disregard the output of the sensor and to apply fixed or preprogrammed conditions for controlling the air/fuel ratio. Typically the purpose of the inhibit signal is to indicate when the sensor is inoperable because of its operating temperature or its physical condition.
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