Method and system for matching air flow in an exhaust gas recirculation system
AssigneeTransportation IP Holdings, LLC
InventorJames Henry Yager
Life of this patent
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Abstract
Various methods and systems are provided for an exhaust gas recirculation system. In one embodiment, an engine method comprises routing exhaust gas from a first cylinder group of an engine to an exhaust gas recirculation passage coupled to both an intake passage and an exhaust passage of the engine, the first cylinder group having a first amount of positive intake and exhaust valve overlap, and routing exhaust gas from a second cylinder group of the engine only to the exhaust passage of the engine, the second cylinder group having a second, smaller amount of positive intake and exhaust valve overlap.
Claims17
An engine system, comprising:
- a first cylinder group coupled exclusively to an exhaust gas recirculation passage configured to route exhaust to an intake passage and an exhaust passage of the engine;
- a second cylinder group coupled exclusively to the exhaust passage of the engine, wherein the intake passage is configured to route exhaust from the exhaust gas recirculation passage to both the first cylinder group and the second cylinder group;
- a first camshaft having cam lobes with a first profile to close exhaust valves of the first cylinder group at a first timing;
- and
- a second camshaft having cam lobes with a second profile to close exhaust valves of the second cylinder group at a second timing, the second timing earlier than the first timing, wherein the exhaust valves of the first cylinder group are closed at the first timing during all operating conditions where exhaust valve events are occurring.
An engine system, comprising:
- a first cylinder group coupled exclusively to an exhaust gas recirculation passage configured to route exhaust to an intake passage and an exhaust passage of the engine;
- a second cylinder group coupled exclusively to the exhaust passage of the engine;
- and
- a control unit storing instructions executable to:
- responsive to a first condition including an exhaust backpressure of the first cylinder group exceeding an exhaust backpressure of the second cylinder group, operate the first cylinder group with a first amount of positive intake and exhaust valve overlap;
- responsive to a second condition including the exhaust backpressure of the first cylinder group being equal to the exhaust backpressure of the second cylinder group, operate the first cylinder group with a second, smaller amount of positive intake and exhaust valve overlap;
- and
- responsive to the first condition and responsive to the second condition, operate the second cylinder group with the second, smaller amount of positive intake and exhaust valve overlap.
A method, comprising:
- during a first condition, routing exhaust gas from a first cylinder group of an engine to an exhaust gas recirculation passage coupled to both an intake passage and an exhaust passage of the engine, and closing exhaust valves of the first cylinder group at a first timing;
- during the first condition, routing exhaust gas from a second cylinder group of the engine only to the exhaust passage of the engine and closing exhaust valves of the second cylinder group at a second timing, the second timing earlier than the first timing;
- and
- adjusting a position of a first valve configured to route exhaust from the first cylinder group to the exhaust passage and a position of a second valve configured to route exhaust from the first cylinder group to the intake passage based on a target amount of exhaust gas recirculation.
Dependencies are inferred from the claim text.