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U.S. Department of Energy
Office of Scientific and Technical Information

System for controlling idle speed of an engine

Patent ·
OSTI ID:6422835

This patent describes a system for controlling idle speed of an engine having a bypass around a throttle valve and a solenoid operated idle speed control valve provided in the bypass, comprising: first means for generating driving pulses for driving the idle speed control valve in dependence on a coolant temperature and an old learning correction value; second means for converting temperature of a solenoid of the control valve to voltage; a map storing normal temperature duty ratios; third means for deriving a normal temperature duty ratio from the map in dependence on duty ratio of the driving pulses and the voltage; a first calculator for producing a difference between the duty ratio of the driving pulses and the derived normal temperature duty ratio; a memory storing the difference as a correction value; detecting means for detecting turning off of an ignition switch and for producing an off signal; a second calculator responsive to the off signal for adding the correction value to the old learning correction value to produce a new learning correction value and for storing the new learning correction value for a subsequent engine operation instead of the old learning correction value.

Assignee:
Fuji Jukogyo Kabushiki Kaisha, Tokyo
Patent Number(s):
US 4787351
OSTI ID:
6422835
Country of Publication:
United States
Language:
English