Higb pressure diesel engine fuel injection pump - has piston with stepped or peripherally grooved top for pressure relief

摘要

The space above the top surface of the piston (5) for a fuel injection pump for a Diesel engine forms a high pressure chamber from which the fuel is injected through the top injection jet. For pressure compensation, the piston has zones where its size is reduced, or alternatively, grooves can be included around the outside of the piston or inside the cylinder wall (2). The piston has a smaller diameter upper part followed by a stepped part (26) where it increases in size again. Alternatively, the top of the piston above the smaller diameter part has smaller diameter zones between larger diameter rings.