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Diagnostic method and arrangement for quantitatively checking actuators in internal combustion engines

  • US 4,794,790 A
  • Filed: 07/17/1987
  • Issued: 01/03/1989
  • Est. Priority Date: 07/19/1986
  • Status: Expired due to Term
First Claim
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1. A diagnostic method for quantitatively checking actuators in the open-loop and closed loop control of operating parameters of an internal combustion engine which includes:

  • a fuel metering apparatus;

    an air-flow sensor; and

    , a central control unit including computer units; and

    , an exhaust system accommodating a lambda control, the actuators including the idle actuator and tank-venting valve (TEV) for effecting a tank ventilation, said actuators having respective hardware chains, the method comprising the steps of;

    supplying increased or reduced air quantities (Δ

    QTEV, Δ

    QLLR) by means of a corresponding control of one of the tank-venting valve (TEV) and the idle actuator (LLS) during the operation of the engine; and

    ,observing feedback of rotational speed changes which occur (rotational speed n=constant;

    nDiagn >

    nalt ; and

    , nDiagn <

    nalt) to provide an indication as to the functioning capability of the hardware chains of said actuators wherein;

    nDiagn is the diagnosed speed of the engine; and

    ,nalt is the engine prior to starting the diagnosis.

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