Idle speed control system
First Claim
1. A method for controlling idling speed of an engine by controlling a bypass throttle connected in parallel to a primary engine throttle and also controlling purge flow through a vapor recovery system into an air/fuel intake of the engine, comprising the steps of:
- positioning the bypass throttle to decrease any difference between a desired engine idle speed and actual engine idle speed;
adjusting the purge flow to maintain said bypass throttle position within a preselected range;
predetermined mass per unit of time; and
decreasing rate of vapor purge in a preprogramed manner in response to said detection step.
2 Assignments
0 Petitions
Accused Products
Abstract
A control system (10) controls both engine idle speed and purge flow through a fuel vapor recovery system (86) into an air/fuel intake of the engine. A bypass throttle valve (72) connected in parallel with a primary engine throttle (62) is controlled by a feedback variable (ISFV) related to a difference between actual idle speed and desired idle speed. Purge flow (pdc) is reduced when the bypass throttle position falls below a dead band provided stoichiometric air/fuel control is maintained.
34 Citations
10 Claims
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1. A method for controlling idling speed of an engine by controlling a bypass throttle connected in parallel to a primary engine throttle and also controlling purge flow through a vapor recovery system into an air/fuel intake of the engine, comprising the steps of:
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positioning the bypass throttle to decrease any difference between a desired engine idle speed and actual engine idle speed; adjusting the purge flow to maintain said bypass throttle position within a preselected range;
predetermined mass per unit of time; anddecreasing rate of vapor purge in a preprogramed manner in response to said detection step. - View Dependent Claims (2, 3, 4)
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5. A method for controlling idling speed of an engine by controlling a bypass throttle connected in parallel to a primary engine throttle and also controlling purge flow of a mixture of purged air and fuel vapors from a vapor recovery system into an air/fuel intake of the engine, comprising the steps of:
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positioning the bypass throttle to decrease any difference between a desired engine idle speed and actual engine idle speed; increasing the purge flow until said positioning step maintains the bypass throttle within a preselected position range; adjusting liquid fuel inducted into the air/fuel intake in response to a compensation value related to mass of the fuel vapors purged into the air/fuel intake per unit of time; detecting when the purged fuel vapors are below a predetermined mass per unit of time; decreasing purge flow in a preprogramed manner in response to said detection step; and decreasing said compensation value in a preprogramed manner in response to said detection step. - View Dependent Claims (6, 7)
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8. A control system for controlling idling speed of an engine, comprising:
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a bypass throttle connected in parallel to a primary engine throttle; idle speed control means for positioning said bypass throttle to decrease any difference between a desired engine idle speed and actual engine idle speed; a vapor recovery system including a purge control means for controlling purge flow of a mixture of purged air and fuel vapors from said vapor recovery system into an air/fuel intake of the engine, said purge control means decreasing said purge flow when said bypass throttle position is less than a preselected fraction of a maximum bypass throttle position and increasing said purge flow when said bypass throttle position is greater than a predetermined fraction of said maximum bypass throttle position; detection means for detecting when said purged fuel vapors are below a predetermined mass per unit of time; and said purge control means decreasing purge flow by predetermined steps in response to each of said detections of said purged fuel vapors being less than said predetermined mass. - View Dependent Claims (9, 10)
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Specification