Internal combustion engine control
First Claim
1. An engine speed control method for controlling engine speed to a target engine speed, comprising the steps of:
- identifying engine operating conditions under which closed-loop engine intake mass airflow rate control is desired;
sampling input signals indicating a current engine operating condition;
storing a correction factor representing an engine intake airflow rate correction to maintain the target engine speed under the current engine operating condition;
sampling an input signal indicating current engine intake airflow rate; and
when the current engine operating condition is an engine operating condition under which closed-loop mass airflow rate control is desired, then (a) determining a deviation of the current engine intake airflow rate away from an expected engine intake airflow rate, (b) establishing a cause of the determined deviation, and (c) selectively applying, depending on the established cause of the determined deviation, the stored correction factor to correct engine intake airflow rate.
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Accused Products
Abstract
Control of engine speed responsive to a deviation in engine speed away from a target speed is applied selectively under closed-loop airflow control operating conditions, such as idle and coastdown operating conditions in response to analysis of a cause of an engine intake airflow deviation away from a modeled airflow. If airflow deviations are determined to have resulted from variation in internal engine friction away from a nominal friction level, the control is applied. If airflow deviations are determined to have resulted from change in internal engine airflow restriction, such as due to contaminant build-up over a period of engine use, then the control is not applied under closed-loop airflow control operating conditions to avoid overcompensating for such deviations.
26 Citations
13 Claims
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1. An engine speed control method for controlling engine speed to a target engine speed, comprising the steps of:
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identifying engine operating conditions under which closed-loop engine intake mass airflow rate control is desired; sampling input signals indicating a current engine operating condition; storing a correction factor representing an engine intake airflow rate correction to maintain the target engine speed under the current engine operating condition; sampling an input signal indicating current engine intake airflow rate; and when the current engine operating condition is an engine operating condition under which closed-loop mass airflow rate control is desired, then (a) determining a deviation of the current engine intake airflow rate away from an expected engine intake airflow rate, (b) establishing a cause of the determined deviation, and (c) selectively applying, depending on the established cause of the determined deviation, the stored correction factor to correct engine intake airflow rate. - View Dependent Claims (2, 3, 4, 5, 6)
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7. A method for controlling internal combustion engine speed, comprising the steps of:
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providing a schedule of open-loop correction factors for correcting engine intake airflow rate as a function of engine operating conditions; establishing a range of engine operating conditions under which closed-loop engine intake airflow rate control is desired; determining a current engine operating condition; selecting an active open-loop correction factor from the provided schedule as the correction factor of the provided schedule corresponding to the current engine operating condition; when the determined current engine operating condition is within the established range of engine operating condition, selectively applying the active open-loop correction factor, by (a) detecting a variation in engine intake airflow rate away from an expected airflow rate for the current engine operating condition, (b) diagnosing a cause of the detected variation, and (c) applying the active open-loop correction factor to correct engine intake airflow rate when the diagnosed cause is a first predetermined cause and not applying the active open-loop correction factor to correct engine intake airflow rate when the diagnosed cause is a second predetermined cause. - View Dependent Claims (8, 9, 10, 11, 12, 13)
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Specification