Methods and systems to control fuel scavenging in a split exhaust engine

Abstract

Methods and systems are provided for adjusting amount of directly injected fuel scavenged via a second exhaust manifold of a split exhaust engine system. In one example, a method may include adjustinga start of injection of a fuel direct injection into an engine cylinder, the cylinder including a first exhaust valve coupled to a first exhaust manifold and a second exhaust valve coupled to a second exhaust manifold, the second exhaust manifold coupled to an intake of the engine, based on a closing timing of the second exhaust valve and dependent on an operating condition, and adjusting a position of a bypass valve of the second exhaust manifold based on the adjusted start of injection. In this way, the amount of scavenged fuel may be increased or decreased based on the operating condition.

Description

technical field [0001] The present description generally relates to systems and methods for engines having split exhaust systems. Background technique [0002] Engines may use boosting devices, such as turbochargers, to increase engine power density. However, engine knock may occur due to increased combustion temperatures. Knocking is especially problematic under boost conditions due to high charge temperatures. The inventors herein have recognized that a split exhaust system can reduce engine knock and increase engine efficiency, wherein a first exhaust manifold delivers exhaust to the turbine of a turbocharger in the exhaust port of the engine, and a second The exhaust manifold delivers exhaust gas recirculation (EGR) to the intake of the engine upstream of the compressor of the turbocharger. In such an engine system, each cylinder may include two intake valves and two exhaust valves, with a first set of cylinder exhaust valves (e.g., blown exhaust valves) being coupled...

AI Technical Summary

Problems solved by technology

However, engine knock may occur due to increased combustion temperature

Knocking

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