Idle speed control for lean burn engine with variable-displacement-like characteristic
First Claim
1. A method for controlling an engine having a first and second group of combustion chambers, comprising:
- inducting air and injecting fuel into the first combustion chamber group at a first average air-fuel ratio;
inducting air and not injecting fuel into the second combustion chamber group;
controlling airflow to at least both said first and second group via an electronically controlled throttle plate of the engine, andadjusting both said injected fuel to the first combustion chamber group and the throttle plate based on a desired engine torque so that an actual speed approaches a desired speed and an air-fuel ratio is controlled within a preselected range.
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Accused Products
Abstract
A method is disclosed for controlling operation of a engine coupled to an exhaust treatment catalyst. Under predetermined conditions, the method operates an engine with a first group of cylinders combusting a lean air-fuel mixture and a second group of cylinders pumping air only (i.e. without fuel injection.) In addition, the engine control method also provides the following features in combination with the above-described split air/lean mode: auto speed control, sensor diagnostics, air-fuel ratio control, adaptive learning, fuel vapor purging, catalyst temperature estimation, and default operation. In addition, the engine control method also disables the split air/lean operating mode under preselected operating conditions.
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Citations
17 Claims
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1. A method for controlling an engine having a first and second group of combustion chambers, comprising:
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inducting air and injecting fuel into the first combustion chamber group at a first average air-fuel ratio; inducting air and not injecting fuel into the second combustion chamber group; controlling airflow to at least both said first and second group via an electronically controlled throttle plate of the engine, and adjusting both said injected fuel to the first combustion chamber group and the throttle plate based on a desired engine torque so that an actual speed approaches a desired speed and an air-fuel ratio is controlled within a preselected range. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for controlling an engine having first and second groups of combustion chambers, comprising:
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controlling airflow to the first and second group of the engine via an electronically controlled throttle plate in an intake of said engine; operating the engine in a first operating mode where air and substantially no injected fuel is provided to the first combustion chamber group, and both air and injected fuel are provided to the second combustion chamber group, and both injected fuel to the second combustion chamber group and the throttle plate are adjusted to vary engine torque so that a determined actual speed approaches a desired speed and an air-fuel ratio is controlled within a preselected range; and operating the engine in a second mode where both air and injected fuel are provided to both the first and second combustion chamber groups, and said air and said injected fuel provided to both said first and second combustion group is adjusted to vary engine torque so that said determined actual speed approaches said desired speed. - View Dependent Claims (11, 12, 13, 14, 15)
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16. A method for controlling a vehicle having an engine having first and second groups of combustion chambers, the method comprising:
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controlling airflow to the first and second group of the engine via an electronically controlled throttle plate in an intake of said engine during at least some operation in a speed control condition; inducting air and injecting fuel into the first group of combustion chambers, inducting air and injecting substantially no fuel into the second group of combustion chambers, and adjusting said injected fuel to the first combustion chamber group and the throttle plate so that a determined speed approaches said desired speed and an air-fuel ratio is controlled within a preselected range; and
;during at least some operation in a preselected condition other than said speed control condition; determining a desired engine output torque based on a driver actuated element and adjusting at least one of fuel injected or air inducted to both cylinder groups based on said desired engine output torque. - View Dependent Claims (17)
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Specification