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US 6,470,854 B1Granted
Air-fuel ratio control with improved fuel supply operation immediately after complete combustion of mixture
AssigneeDenso Corporation
InventorsYasuo Hirata, Hidehiko Asama
Life of this patent
Estimating the term…
Abstract
In an air fuel ratio control for engines, a target operation characteristic of engine speed is set based on a coolant temperature when the engine starts cranking. The target engine speed is variable with time after the engine cranking has started and converges to a speed value lower than a normal target idle speed. Immediately after a complete combustion of air-fuel mixture suplied to the engine is detected, an actual engine speed is compared with a target engine speed corresponding to the target operation characteristics, and an air-fuel ratio of the mixture supplied to the engine is controlled based on a comparison result.
Claims27
An air-fuel ratio control apparatus for internal combustion engines comprising:
- target characteristics setting means for setting target operation characteristics of a predetermined engine speed parameter which should occur after a complete combustion of air-fuel mixture supplied to an engine, the predetermined engine speed parameter being indicative of an engine rotation speed;
- and
- air-fuel ratio control means for comparing actual operation characteristics of the predetermined engine speed parameter with the target operation characteristics, and controlling an air-fuel ratio of the air-fuel mixture based on a comparison result so that the actual operation characteristics follow the target operation characteristics, said controlling of the air-fuel ratio of the air-fuel mixture based on the comparison result being started after the complete combustion of the air-fuel mixture.
An air-fuel ratio control apparatus for internal combustion engines comprising:
- target characteristics setting means for setting target operation characteristics of a predetermined engine speed parameter which should occur after a complete combustion of air-fuel mixture supplied to an engine, the predetermined engine speed parameter being indicative of an engine rotation speed;
- air-fuel ratio control means for comparing actual operation characteristics of the predetermined engine speed parameter with the target operation characteristics, and controlling an air-fuel ratio of the air-fuel mixture based on a comparison result so that the actual operation characteristics follow the target operation characteristics, said controlling of the air-fuel ratio of the air-fuel mixture based on the comparison result being started after the complete combustion of the air-fuel mixture;
- dither control means for effecting a fuel injection dither control at a predetermined time after the complete combustion of air-fuel mixture, the dither control being for temporarily changing the air-fuel ratio of air-fuel mixture;
- air-fuel ratio determination means for determining richness/leanness of the air-fuel ratio of air-fuel mixture based on changes in the predetermined engine speed parameter caused by the dither control;
- and
- wherein the air-fuel ratio control means corrects a control amount of the air-fuel ratio based on the determined richness/leanness of the air-fuel ratio.
3 more elements
An air-fuel ratio control method for engines comprising:
- starting cranking an engine by supplying air-fuel mixture to the engine;
- detecting a complete combustion of the air-fuel mixture in the engine;
- setting a target engine speed after a detection of the complete combustion, the target engine speed being varied to rise above an engine idle speed after the complete combustion and then fall toward the engine idle speed as time elapses;
- comparing an actual engine speed with the target engine speed;
- and
- correcting the air-fuel ratio of air-fuel mixture supplied to the engine based on a comparison result of the comparing step so that the actual engine speed follows the target engine speed, the correcting of the air-fuel ratio based on the comparison result being started after complete combustion of the air-fuel mixture.
3 more elements
An air-fuel ratio control method for engines comprising:
- starting cranking an engine by supplying air-fuel mixture to the engine;
- detecting a complete combustion of the air-fuel mixture in the engine;
- setting a target engine speed after a detection of the complete combustion, the target engine speed being varied to rise above an engine idle speed after the complete combustion and then fall toward the engine idle speed as time elapses;
- comparing an actual engine speed with the target engine speed;
- correcting the air-fuel ratio of air-fuel mixture supplied to the engine based on a comparison result of the comparing step so that the actual engine speed follows the target engine speed, the correcting of the air-fuel ratio based on the comparison result being started after complete combustion of the air-fuel mixture;
- changing the air-fuel ratio of air fuel mixture temporarily to a leaner ratio after the complete combustion while the actual engine speed is rising;
- detecting changes in the actual engine speeds before and after the changing step;
- and
- correcting the air-fuel ratio of air-fuel mixture further based on the detected changes in the actual engine speeds.
6 more elements
An air-fuel ratio control apparatus for internal combustion engines comprising:
- a target characteristics setter for setting target operation characteristics of a predetermined engine speed parameter which should occur after a complete combustion of air-fuel mixture supplied to an engine, the predetermined engine speed parameter being indicative of an engine rotation speed;
- and
- an air-fuel ratio controller for comparing actual operation characteristics of the predetermined engine speed parameter with the target operation characteristics, and controlling an air-fuel mixture based on a comparison result so that the actual operation characteristics follow the target operation characteristics, said controlling of the air-fuel ratio of the air-fuel mixture based on the comparison result being started after the complete combustion of the air-fuel mixture.
An air-fuel ratio control apparatus for internal combustion engines comprising:
- a target characteristics setter for setting target operation characteristics of a predetermined engine speed parameter which should occur after a complete combustion of air-fuel mixture supplied to an engine, the predetermined engine speed parameter being indicative of an engine rotation speed;
- an air-fuel ratio controller for comparing actual operation characteristics of the predetermined engine speed parameter with the target operation characteristics, and controlling an air-fuel mixture based on a comparison result so that the actual operation characteristics follow the target operation characteristics, said controlling of the air-fuel ratio of the air-fuel mixture based on the comparison result being started after the complete combustion of the air-fuel mixture;
- a dither controller for effecting a fuel injection dither control at a predetermined time after the complete combustion of air-fuel mixture, the dither control being for temporarily changing the air-fuel ratio of air-fuel mixture;
- an air-fuel ratio determiner that determines richness/leanness of the air-fuel ratio of air-fuel mixture based on changes in the predetermined engine speed parameter caused by the dither control;
- and
- wherein the air-fuel ratio controller corrects a control amount of the air-fuel ratio based on the determined richness/leanness of the air-fuel ratio.
3 more elements
Dependencies are inferred from the claim text.