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Fuel metering control system for internal combustion engine

  • US 5,638,802 A
  • Filed: 02/23/1996
  • Issued: 06/17/1997
  • Est. Priority Date: 02/25/1995
  • Status: Expired due to Term
First Claim
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1. A system for controlling fuel metering for a multi-cylinder internal combustion engine, comprising:

  • an air/fuel ratio sensor located in an exhaust system of the engine for detecting an air/fuel ratio in exhaust gas of the engine;

    engine operating condition detecting means for detecting engine operating conditions including at least engine speed and engine load;

    basic fuel injection quantity determining means coupled to said engine operating condition detecting means, for determining a basic quantity of fuel injection for a cylinder of the engine based on at least the detected engine operating conditions;

    a feedback loop means coupled to said basic fuel injection quantity determining means, and having an adaptive controller and an adaptation mechanism coupled to said adaptive controller for estimating controller parameters, said adaptive controller calculating a feedback correction coefficient using internal variables that include at least said controller parameters, to correct the basic quantity of fuel injection to bring a controlled variable obtained based at least on the detected air/fuel ratio to a desired value;

    fuel cutoff determining means for determining fuel cutoff based on the detected engine operating conditions;

    output fuel injection quantity determining means for determining an output quantity of fuel injection, said output fuel injection quantity determining means correcting the basic quantity of fuel injection using said feedback correction coefficient when engine operation is discriminated to be in a feedback control region, said output fuel injection quantity determining means determining the output quantity of fuel injection to be zero to cut a supply of fuel into the engine off when said fuel cutoff determining means determines that the fuel is cut off; and

    fuel injection means coupled to said output fuel injection quantity determining means, for injecting fuel into the cylinder of the engine based on the output quantity of fuel injection;

    wherein;

    said feedback loop means set at least one of the internal variables of the adaptive controller to a predetermined value when the supply of fuel is resumed after termination of the fuel cutoff, and causes the adaptive controller to calculate the feedback correction coefficient based on the internal variables set to the predetermined value.

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