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US 8,656,870 B2Granted
Control strategy for multi-stroke engine system
AssigneeFord Global Technologies, LLC
InventorGopichandra Surnilla
Life of this patent
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Abstract
An engine system and a method of operation are described. The engine may be operating in two-stroke and four-stroke modes while still maintaining a target exhaust air-fuel ratio.
Claims15
A method of operating an internal combustion engine, comprising:
- operating the engine in a two stroke cycle by:
- initiating combustion of a rich air and fuel mixture in a cylinder of the internal combustion engine;
- receiving intake air into the cylinder via an intake poppet valve of the cylinder after initiating said combustion of the rich air and fuel mixture;
- exhausting an exhaust gas mixture from the cylinder via an exhaust poppet valve, said exhaust gas mixture including at least some of the received intake air and the combusted rich air and fuel mixture;
- and
- adjusting a timing of at least one of the intake poppet valve and the exhaust poppet valve of the cylinder to vary a composition of the exhaust gas mixture.
3 more elements
An engine system for a vehicle propulsion system, comprising:
- an internal combustion engine including at least one cylinder having a piston;
- an intake passage in fluid communication with the cylinder via at least one intake poppet valve;
- an intake valve actuator coupled to the intake poppet valve;
- an exhaust passage in fluid communication with the cylinder via at least one exhaust poppet valve;
- an exhaust valve actuator coupled to the exhaust poppet valve;
- a control system configured to:
- operate the cylinder in a two stroke cycle during a first operating condition by combusting an air and fuel mixture in the cylinder every two strokes of the piston, and operating the intake and exhaust valve actuators to adjust an opening overlap between the intake poppet valve and the exhaust poppet valve to vary a resulting composition of an exhaust gas mixture provided to the exhaust passage from the cylinder via the exhaust poppet valve;
- operate the cylinder in a four stroke cycle during a second operating condition by combusting an air and fuel mixture in the cylinder every four strokes of the piston;
- adjust the air and fuel mixture combusted in the cylinder while operating in the two stroke cycle to a richer air-fuel ratio to produce the resulting exhaust gas mixture having a leaner air-fuel ratio;
- and
- adjust the air and fuel mixture combusted in the cylinder while operating in the four stroke to the leaner air-fuel ratio to produce the resulting exhaust gas mixture having the leaner air-fuel ratio.
8 more elements
Dependencies are inferred from the claim text.