The patent badge is an abbreviated version of the USPTO patent document. The patent badge does contain a link to the full patent document.
The patent badge is an abbreviated version of the USPTO patent document. The patent badge covers the following: Patent number, Date patent was issued, Date patent was filed, Title of the patent, Applicant, Inventor, Assignee, Attorney firm, Primary examiner, Assistant examiner, CPCs, and Abstract. The patent badge does contain a link to the full patent document (in Adobe Acrobat format, aka pdf). To download or print any patent click here.
Patent No.:
Date of Patent:
Jul. 06, 1982
Filed:
Apr. 02, 1981
Clifford R Carlson, Fenton, MI (US);
Joseph M Kotzan, Pontiac, MI (US);
Leo H Voelkle, Keego Harbor, MI (US);
General Motors Corporation, Detroit, MI (US);
Abstract
Idle air control apparatus for a vehicle driving internal combustion engine having an air induction passage includes a control valve in the air induction passage controlled by a stepper motor in response to the arithmetic count of applied electrical pulses, a register effective to store a valve control number representing the currently desired position of the control valve, apparatus effective upon occurrence of a predetermined engine loading event to change the valve control number in response thereto, an up-down counter effective to arithmetically count the pulses applied to the stepper motor and thus indicate actual control valve position, a closed loop control effective to compare the contents of the up-down counter and register and apply pulses to the stepper motor at the first predetermined rate to reduce any difference therebetween and a speed trim loop active only during occurrence of a predetermined steady state idle condition to compare actual engine speed with the desired engine idle speed and arithmetically change the valve control number in the register at a second predetermined rate substantially slower than the first predetermined rate to reduce any difference between said speeds. Thus idle air control responds to large, sudden engine load changes and environmental factors to prevent engine stall but ignores small random speed fluctuations to maintain a stable engine idle.