Engine ignition timing control system and method
AssigneeMitsubishi Jidosha Kogyo Kabushiki Kaisha
InventorKazuhide Togai
Life of this patent
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Abstract
An ignition timing control system and method for multicylinder internal combustion engine, utilizing a variable valve operating system such as variable valve timing system and a partial cylinder operating system. An engine control unit calculates a standard ignition timing for each cylinder according to the valve operating condition, rotational speed of the engine and intake air pressure. The control unit also calculates a target ignition timing by compensating the standard ignition timing according to an operating condition of the vehicle and controls an ignition driver to operate an ignitor associated with each cylinder at the target ignition timing.
Claims22
A system for controlling ignition timing for an internal combustion engine comprising:
- a plurality of cylinders;
- intake valves disposed in each of said cylinders;
- exhaust valves disposed in each of said cylinders;
- valve motion condition control means for selectively controlling an operating condition of at least one of said intake valves and said exhaust valves;
- engine revolution speed detecting means for detecting engine revolution speed of an engine to produce an output signal of engine revolution speed data of the engine;
- valve motion condition determining means for determining valve motion condition of the engine to produce an output signal representative of valve motion condition data for each of said cylinders;
- said engine further including an intake manifold;
- intake air pressure detecting means for detecting intake pressure of air introduced into said intake manifold to produce an output signal representative of air pressure data of said intake manifold;
- a plurality of standard ignition timing calculating maps storing ignition timing data in relation to said air pressure data and said engine revolution speed, each varying with regard to said valve motion condition data;
- standard ignition timing calculating means for selecting one of said standard ignition timing maps in response to said valve motion condition data to calculate a standard ignition timing of each of the cylinders;
- target ignition timing calculating means for calculating for each of said cylinders a target ignition timing by compensating the standard ignition timing on the basis of the operating condition of said engine;
- said engine further including an ignitor associated with each of said cylinders;
- and
- ignition driving means for driving the said ignitor associated with each of said cylinders of the engine at said target ignition timing.
A method for controlling ignition timing for an internal combustion engine comprising the steps of:
- detecting engine revolution speed of an engine to produce an output signal of engine revolution speed data of the engine;
- determining valve motion condition data of the engine to produce a valve motion condition data indicative of an operating condition of at least one of the intake valves and exhaust valves disposed in each of the cylinders assembled in the engine;
- detecting intake air pressure data of air introduced into the intake manifold to produce an output signal representative of said air pressure data;
- establishing a plurality of standard ignition timing calculating maps each of which shows said air pressure data of the intake manifold and said engine revolution speed data varied in response to said valve motion condition data;
- selecting one of said standard ignition timing maps in response to said valve motion condition data and calculating a standard ignition timing of each of the cylinders;
- calculating for each of said cylinders a target ignition timing by compensating the standard ignition timing on the basis of the operating condition of the engine;
- and
- driving an ignitor associated with each of said cylinders of the engine at said target ignition timing.
Dependencies are inferred from the claim text.