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US 6,637,386 B2Granted
Variable valve timing apparatus
AssigneeMitsubishi Jidosha Kogyo Kabushiki Kaisha
InventorsShinichi Murata, Fumiaki Hiraishi, Kazuhiro Okuno, Hideo Nakai, Osamu Nakayama, Takashi Dogahara
Life of this patent
Estimating the term…
Abstract
Just after the start of an engine at cold start, an overlap in the opening time of an intake valve (7a) and an exhaust valve (7b) is controlled to include an intake stroke range, such that liquid fuel in an intake port (11) flows into a cylinder with the downward movement of a piston (16) without being directly exhausted to an exhaust side, so that the fuel can be combusted without fail.
Claims25
A variable valve timing apparatus, comprising:
- an exhaust valve that closes during an intake stroke after a top dead center succeeding an exhaust stroke;
- an intake valve timing varying unit for selectively varying an open timing of the intake valve, said intake valve timing varying unit being capable of advancing the open timing of the intake valve such that the intake valve opens during the exhaust stroke;
- and
- a control unit for controlling said intake valve timing varying unit such that, at a cold start of an engine, an overlap in an open time between the exhaust valve and the intake valve lies in the intake stroke for a predetermined period of time, and such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve thereafter.
1 more element
A variable valve timing apparatus comprising:
- an exhaust valve that closes during an intake stroke after a top dead center succeeding an exhaust stroke;
- an intake valve timing varying unit for selectively varying an open timing of the intake valve, said intake valve timing varying unit being capable of advancing the open timing of the intake valve such that the intake valve opens during the exhaust stroke;
- a control unit for controlling said intake valve timing varying unit such that, at a cold start of an engine, an overlap in an open time between the exhaust valve and the intake valve lies in the intake stroke, and such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve thereafter;
- and
- an exhaust valve timing varying unit for selectively varying controlling a close timing of the exhaust valve, said exhaust valve timing varying unit being capable of retarding the close timing of the exhaust valve such that the exhaust valve closes during the intake stroke,
- wherein said control unit controls said intake valve timing varying unit and said exhaust valve timing varying unit such that, at the cold start of the engine, the overlap in the open time between the exhaust valve and the intake valve lies in the intake stroke, and such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve thereafter.
3 more elements
A variable valve timing apparatus, comprising:
- an exhaust valve that closes during an intake stroke after a top dead center succeeding an exhaust stroke;
- an intake valve timing varying unit for selectively varying an open timing of the intake valve, said intake valve timing varying unit being capable of advancing the open timing of the intake valve such that the intake valve opens during the exhaust stroke;
- and
- a control unit for controlling said intake valve timing varying unit such that, at a cold start of an engine, an overlap in an open time between the exhaust valve and the intake valve lies in the intake stroke, and such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve thereafter,
- wherein said control unit maintains the overlap at zero until the overlap that lies in the intake stroke is established.
2 more elements
A variable valve timing apparatus, comprising:
- an exhaust valve that closes during an intake stroke after a top dead center succeeding an exhaust stroke;
- an intake valve timing varying unit for selectively varying an open timing of the intake valve, said intake valve timing varying unit being capable of advancing the open timing of the intake valve such that the intake valve opens during the exhaust stroke;
- and
- a control unit for controlling said intake valve timing varying unit such that, at a cold start of an engine, an overlap in an open time between the exhaust valve and the intake valve lies in the intake stroke, and such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve thereafter,
- wherein said control unit changes from the overlap that lies in the intake stroke to the overlap that lies in the exhaust stroke at a predetermined time after a first combustion of the engine.
2 more elements
A method of varying a valve timing, comprising:
- controlling an open timing of an intake valve such that, at a cold start of an engine, an overlap in an open time between an exhaust valve and the intake valve lies in an intake stroke after a top dead center succeeding an exhaust stroke for a predetermined period of time;
- and
- controlling the open timing of the intake valve such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve thereafter.
A method of varying a valve timing comprising:
- controlling an open timing of an intake valve such that, at a cold start of an engine, an overlap in an open time between an exhaust valve and the intake valve lies in an intake stroke after a top dead center succeeding an exhaust stroke;
- controlling the open timing of the intake valve such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve;
- and
- maintaining the overlap at zero until the overlap that lies in the intake stroke is established.
1 more element
A method of varying a valve timing, comprising:
- controlling an open timing of an intake valve such that, at a cold start of an engine, an overlap in an open time between an exhaust valve and the intake valve lies in an intake stroke after a top dead center succeeding an exhaust stroke;
- controlling the open timing of the intake valve such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve;
- and
- increasing the overlap that lies in the exhaust stroke while the close timing of the exhaust valve is being advanced.
1 more element
A method of varying a valve timing comprising
- controlling an open timing of an intake valve such that, at a cold start of an engine, an overlap in an open time between an exhaust valve and the intake valve lies in an intake stroke after a top dead center succeeding an exhaust stroke;
- controlling the open timing of the intake valve such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve;
- and
- changing from the overlap that lies in the intake stroke to the overlap that lies in the exhaust stroke at a predetermined time after a first combustion of the engine.
1 more element
A method of varying a valve timing comprising:
- controlling an open timing of an intake valve such that, at a cold start of an engine, an overlap in an open time between an exhaust valve and the intake valve lies in an intake stroke after a top dead center succeeding an exhaust stroke;
- controlling the open timing of the intake valve such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve;
- and
- advancing the close timing of the exhaust valve after increasing the overlap that lies in the exhaust stroke.
1 more element
A method of varying a valve timing, comprising:
- controlling an open timing of an intake valve such that, at a cold start of an engine, an overlap in an open time between an exhaust valve and the intake valve lies in an intake stroke after a top dead center succeeding an exhaust stroke;
- controlling the open timing of the intake valve such that the overlap lies in the exhaust stroke by advancing the open timing of the intake valve;
- detecting an operating state of the engine;
- and
- reducing a speed at which the open timing of the intake valve is changed based on the detected operating state.
2 more elements
Dependencies are inferred from the claim text.