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Idling speed control system for outboard motor

  • US 20020086593A1
  • Filed: 12/28/2001
  • Published: 07/04/2002
  • Est. Priority Date: 12/28/2000
  • Status: Active Grant
First Claim
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1. A system for controlling an idling speed for an outboard motor mounted on a boat and equipped with an internal combustion engine whose output is connected to a propeller through a clutch such that the boat is propelled forward or reverse when the clutch is changed to a neutral position to a forward position or a reverse position, comprising:

  • a secondary air supplier that supplies secondary air trough a passage that is connected to an air intake pipe downstream of a throttle valve and that is equipped with a secondary air control valve such that amount of secondary air is supplied to the air intake pipe in response to an opening of the secondary air control valve;

    clutch position detecting means for detecting a position of the clutch;

    engine operating condition detecting means for detecting parameters indicative of operating conditions of the engine including at least an engine speed;

    desired value determining means for determining a desired idling speed based on the detected position of the clutch and for determining a desired secondary air supply amount such that a difference between the determined desired idling speed and the detected engine speed decreases; and

    valve controlling means for controlling the opening of the valve to a value that effects the desired secondary air supply amount;

    wherein the desired value determining means including;

    comparing means for calculating a change of the desired secondary air supply amount and for comparing the change with a predetermined value when it is determined based on the detected position of the clutch that the clutch is changed;

    change direction determining means for determining whether the change is in an increasing direction or in a decreasing direction; and

    correcting means for correcting the desired secondary air supply amount by a predetermined correction amount in the determined direction, when the change is greater than the predetermined value.

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