FIELD

The present description relates generally to a prechamber of an engine.

BACKGROUND/SUMMARY

Engines have in the past utilized prechamber combustion to increase combustion efficiency and correspondingly reduce emissions. Prechamber combustion systems may include an auxiliary prechamber above or within the main combustion chamber with an ignition device and fuel injector coupled to the auxiliary prechamber. In such systems, combustion unfolds in the following sequence; (i) a small amount of fuel is directly injected into the prechamber, (ii) spark is provided to the air/fuel mixture in the prechamber; and (iii) the hot gas jets into the main combustion chamber to ignite the charge disposed therein. Jetting the ignited gas into the main combustion chamber in this manner enables hot gas jets to penetrate deeper into the main combustion chamber, causing more evenly distributed ignition, when compared to engines that do not employ prechamber schemes.

In some prechambers, issues may arise from residual gases from a previous combustion cycle being present in an interior volume of the prechamber. The residual gases may block an air/fuel mixture from within the combustion chamber to flow into the prechamber, and thus, may not be exposed to an ignition device arranged therein. One approach to solve this issue is to include an auxiliary air pump configured to clear the residual gases prior to combustion.

However, the inventors have identified some issues with the approaches described above. For example, the auxiliary air pump increases a packaging size of the prechamber while also further complicating routines thereof. Additionally, cold-start emissions associated with unburned fuel may not be reduced.

In one example, the issues described above may be addressed by a system for a reservoir fluidly coupled to each of a compressor and a prechamber. In this way, unburned fuel from a cold-start may be stored in the reservoir and mixed with boost air during future combustion conditions.

As one example, a valve may be configured to adjust a direction a gas flows between the reservoir and the prechamber. The valve may be opened during some conditions of a cold-start to flow exhaust gases comprising a high amount of unburned fuel into the reservoir. The valve may also be opened during other conditions to flow boost air from the compressor to the prechamber to clear residual gases and enhance air/fuel mixing.

It should be understood that the summary above is provided to introduce in simplified form a selection of concepts that are further described in the detailed description. It is not meant to identify key or essential features of the claimed subject matter, the scope of which is defined uniquely by the claims that follow the detailed description. Furthermore, the claimed subject matter is not limited to implementations that solve any disadvantages noted above or in any part of this disclosure.

