Engine combustion controller
First Claim
1. A combustion controller of an engine having a fuel supply system for supplying fuel, wherein the combustion controller selects a combustion mode performed by the engine from either one of lean combustion, in which an air fuel mixture leaner than a stoichiometric mixture is burned, and stoichiometric combustion, in which a stoichiometric mixture is burned, in accordance with an operating state of the engine, and feedback controls the air fuel ratio of the air fuel mixture when the stoichiometric combustion is performed using an air fuel ratio feedback compensating value, which is set in accordance with a component concentration in an exhaust gas, the controller comprising:
- a preliminary testing means for testing the fuel supply system and determining that the fuel supply system is in a normal state when one of a plurality of predetermined first conditions is satisfied, wherein the first conditions include a condition using the feedback compensating value;
a lean combustion prohibiting means for prohibiting the lean combustion when the preliminary testing means determines that the state of the fuel supply system is ambiguous; and
a main testing means for testing the fuel supply system and determining that the fuel supply system is in an abnormal state when one of a plurality of predetermined second conditions is satisfied, wherein the second conditions include a condition using the feedback compensating value.
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Accused Products
Abstract
An engine combustion controller for an engine having a fuel supply system selects an engine combustion mode from one of lean combustion, in which an air fuel mixture leaner than a stoichiometric mixture is burned, and stoichiometric combustion, in which a stoichiometric mixture is burned, in accordance with an operating state of the engine and controls, via feedback, the air fuel ratio of the air fuel mixture when the stoichiometric combustion is performed using air-fuel ratio compensating value that are based on the composition of the engine exhaust gas. A preliminary tester checks the fuel supply system and determines that the fuel supply system is in a normal state when certain preliminary test conditions are satisfied, which includes checking the feedback compensating value. A prohibiter prevents lean combustion when the preliminary tester determines that the state of the fuel supply system is ambiguous. A main tester tests the fuel supply system and determines that the fuel supply system is in an abnormal state when certain main test conditions are satisfied, which includes checking the feedback compensating value.
33 Citations
20 Claims
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1. A combustion controller of an engine having a fuel supply system for supplying fuel, wherein the combustion controller selects a combustion mode performed by the engine from either one of lean combustion, in which an air fuel mixture leaner than a stoichiometric mixture is burned, and stoichiometric combustion, in which a stoichiometric mixture is burned, in accordance with an operating state of the engine, and feedback controls the air fuel ratio of the air fuel mixture when the stoichiometric combustion is performed using an air fuel ratio feedback compensating value, which is set in accordance with a component concentration in an exhaust gas, the controller comprising:
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a preliminary testing means for testing the fuel supply system and determining that the fuel supply system is in a normal state when one of a plurality of predetermined first conditions is satisfied, wherein the first conditions include a condition using the feedback compensating value;
a lean combustion prohibiting means for prohibiting the lean combustion when the preliminary testing means determines that the state of the fuel supply system is ambiguous; and
a main testing means for testing the fuel supply system and determining that the fuel supply system is in an abnormal state when one of a plurality of predetermined second conditions is satisfied, wherein the second conditions include a condition using the feedback compensating value. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9)
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10. A method for controlling combustion in an engine, which has a fuel supply system for supplying fuel, by selecting a combustion mode performed by the engine from either one of lean combustion, in which an air fuel mixture leaner than a stoichiometric air fuel mixture is burned, and stoichiometric combustion, in which a stoichiometric air fuel mixture is burned, in accordance with an operating state of the engine, and feedback controlling an air fuel ratio of the air fuel mixture when the stoichiometric combustion is performed, the method comprising:
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setting an air fuel ratio feedback compensating value in accordance with a component concentration in an exhaust gas when executing feedback control during stoichiometric combustion;
preliminarily testing the fuel supply system and determining that the fuel supply system is in a normal state when one of a plurality of predetermined first conditions is satisfied, wherein the first conditions include a condition using the feedback compensating value;
prohibiting the lean combustion when the state of the fuel supply system is determined to be ambiguous in the preliminary testing step; and
main testing the fuel supply system and determining that the fuel supply system is in an abnormal state when one of a plurality of predetermined second conditions is satisfied, wherein the second conditions include a condition using the feedback compensating value. - View Dependent Claims (11, 12, 13, 14, 15, 16, 17, 18)
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19. A method of controlling engine combustion comprising the steps of:
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performing a preliminary test while the engine temperature is less than a predetermined temperature, the preliminary test for detecting a normality in a fuel system that provides fuel to the engine;
performing stoichiometric combustion and inhibiting lean combustion if an abnormality in the fuel system is detected by the preliminary test;
after the engine temperature exceeds the predetermined temperature, performing air fuel ratio feedback control for stoichiometric combustion for a predetermined time period;
performing a main test after the engine temperature exceeds the predetermined temperature and the predetermined time period has expired, the main test for detecting abnormalities in the fuel system using a feedback compensating coefficient calculated via the feedback control, wherein the main test prohibits lean combustion while an abnormality is detected. - View Dependent Claims (20)
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Specification