System and method for staged pre-chamber purging
AssigneeCaterpillar Inc.
InventorsJaswinder Singh, Martin L. Willi, Patrick J. Seiler, Michael Bardell
Life of this patent
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Abstract
An internal combustion engine includes low and high pressure turbochargers connected in series. An engine cylinder has an intake valve that fluidly connects a main chamber of the engine cylinder with an outlet of the high pressure compressor through an intake passage. An exhaust gas recirculation passage is fluidly interconnected between exhaust and intake conduits. A pre-chamber encloses a spark plug and is fluidly open with the main chamber of the engine cylinder. A first fluid path extends from the intake passage directly to the pre-chamber, and a second fluid path extends from the intermediate passage directly to the pre-chamber.
Claims13
An internal combustion engine, comprising:
- a low pressure (LP) turbocharger having a LP compressor;
- a high pressure (HP) turbocharger having a HP compressor connected in series with the LP compressor along an intermediate passage, and a HP turbine;
- an engine cylinder having an intake valve that fluidly connects a main chamber of the engine cylinder with an outlet of the HP compressor through an intake passage, and an exhaust valve that fluidly connects the main chamber with an inlet of the HP turbine via an exhaust conduit;
- an exhaust gas recirculation (EGR) passage fluidly interconnected between the exhaust conduit and the intake passage;
- a pre-chamber enclosing a spark plug and being fluidly open with the main chamber of the engine cylinder;
- a first fluid path extending from the intake passage directly to the pre-chamber;
- and
- a second fluid path extending from the intermediate passage directly to the pre-chamber.
A method for purging a pre-chamber that contains a spark plug and is associated with a main combustion chamber of a reciprocal piston internal combustion engine, the method comprising:
- opening an intake valve at a beginning of an intake stroke for an engine cylinder;
- providing an intake charge directly into the pre-chamber and the main combustion chamber along parallel but separate flow paths in a first purge stage, the intake charge containing fuel, air and recirculated exhaust gas;
- closing the intake valve while continuing the intake stroke;
- providing a rich charge directly into the pre-chamber from an intermediate compressor stage in a second purge stage, the rich charge containing fuel and air but not recirculated exhaust gas;
- wherein the intake charge is provided to the pre-chamber along a first fluid path, and wherein the rich charge is provided to the pre-chamber along a second fluid path;
- compressing the main combustion chamber and pre-chamber during a compression stroke;
- igniting the rich charge in the pre-chamber;
- and
- igniting the intake charge in the main combustion chamber.
Dependencies are inferred from the claim text.