Method and apparatus for optimum control of internal combustion engines
First Claim
1. In a method for optimum control of an internal combustion engine comprising the steps of changing an air-fuel ratio alternately to richer and leaner directions with respect to a basic air-fuel ratio by a dither quantity during a dither period, operating said engine by supplying said engine with a mixture of the changed air-fuel ratio, detecting a resultant change in an output of said engine, deciding the direction of a change of the air-fuel ratio toward an optimum air-fuel ratio on the basis of the result of said detection, and modifying the basic air-fuel ratio in the direction of said change toward an optimum air-fuel ratio on the basis of the result of said decision, thereby optimizing fuel consumption of said engine;
- wherein said optimum control method further comprises the steps of detecting an operating state of said engine and producing signals associated with the operating state of said engine including a rotational speed of said engine which is used to detect the change in the output of said engine in accordance with a change therein, and changing at least one of said dither period and dither quantity in accordance with said signals, and wherein the changing of the air-fuel ratio is effected by dithering an air supply quantity to said engine, and the modifying of the basic air-fuel ratio is effected by modifying a basic fuel supply quantity to said engine in the direction of improving the output of said engine, and wherein the direction of the change in the output of said engine is decided in accordance with the relation between the engine rotational speeds detected at the dithering of the air supply quantity to said engine on a first basic fuel supply quantity to said engine and those detected at the dithering of the air supply quantity to said engine on a second basic fuel supply quantity to said engine.
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Abstract
In a method and an apparatus for optimum control of an internal combustion engine, an air-fuel ratio is dithered by a dither amount from a basic air-fuel ratio and the engine is operated with the dithered air-fuel ratio. A resultant change of the output state of the engine is detected, and the direction of improving fuel consumption is decided by the change of the output state of the engine so that the basic air-fuel ratio is changed in that direction. Either the dither period during which the engine is operated with different selected air-fuel ratios or the dither amount is determined with elevated precision by a signal detected in association with the output state of the engine.
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Citations
11 Claims
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1. In a method for optimum control of an internal combustion engine comprising the steps of changing an air-fuel ratio alternately to richer and leaner directions with respect to a basic air-fuel ratio by a dither quantity during a dither period, operating said engine by supplying said engine with a mixture of the changed air-fuel ratio, detecting a resultant change in an output of said engine, deciding the direction of a change of the air-fuel ratio toward an optimum air-fuel ratio on the basis of the result of said detection, and modifying the basic air-fuel ratio in the direction of said change toward an optimum air-fuel ratio on the basis of the result of said decision, thereby optimizing fuel consumption of said engine;
wherein said optimum control method further comprises the steps of detecting an operating state of said engine and producing signals associated with the operating state of said engine including a rotational speed of said engine which is used to detect the change in the output of said engine in accordance with a change therein, and changing at least one of said dither period and dither quantity in accordance with said signals, and wherein the changing of the air-fuel ratio is effected by dithering an air supply quantity to said engine, and the modifying of the basic air-fuel ratio is effected by modifying a basic fuel supply quantity to said engine in the direction of improving the output of said engine, and wherein the direction of the change in the output of said engine is decided in accordance with the relation between the engine rotational speeds detected at the dithering of the air supply quantity to said engine on a first basic fuel supply quantity to said engine and those detected at the dithering of the air supply quantity to said engine on a second basic fuel supply quantity to said engine.
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2. A method for optimum control of an internal combustion engine comprising the steps of changing an air-fuel ratio alternately to richer and leaner directions with respect to a basic air-fuel ratio by a dither quantity during a dither period, operating said engine by supplying said engine with a mixture of the changed air-fuel ratio, detecting a resultant change in an output of said engine, deciding the direction of a change of the air-fuel ratio toward an optimum air-fuel ratio on the basis of the result of said detection, and modifying the basic air-fuel ratio in the direction of said change toward an optimum air-fuel ratio on the basis of the result of said decision, thereby optimizing fuel consumption of said engine;
wherein said optimum control method further comprises the steps of detecting an operating state of said engine and producing signals associated with the operating state of said engine, and changing at least one of said dither period and dither quantity in accordance with said signals, and wherein the changing of the air-fuel ratio is effected by dithering an air supply quantity to said engine, and the modifying of the basic air-fuel ratio is effected by modifying a basic fuel supply quantity to said engine in the direction of improving the output of said engine in accordance with said signals. - View Dependent Claims (3, 4, 5, 6, 8)
- 7. An apparatus for optimum control of an internal combustion engine comprising an intake pipe, a throttle valve disposed in said intake pipe, a bypass air control device connected to said intake pipe in a manner to bypass said throttle valve, a fuel supply device, an engine speed sensor, an intake pressure sensor and an operating unit, input terminals to said operating unit being connected to respective output terminals of said engine speed sensor and intake pressure sensor, output terminals of said operating unit being connected to respective input terminals of said bypass air control device and said fuel supply device, said operating unit computing at least one of a dither period and a dither quantity of a dither signal for dithering an air-fuel ratio of a mixture gas supplied to said engine on the basis of the input signals thereto and outputting said dither signal, energizing said bypass air control device by said dither signal to effect dithering of an air supply quantity to said engine, thereby effecting dithering of the air-fuel ratio above and below a basic air-fuel ratio, deciding a direction of a change of the air-fuel ratio for improving an output of said engine on the basis of the input signal from said engine speed sensor, and optimizing fuel consumption of said engine by modifying a basic fuel supply quantity to said engine in the direction of improving the output of said engine.
Specification