Short seat fuel injection nozzle valve

Claim 1

A differential valve assembly in the fuel injection nozzle assembly for an internal combustion engine comprising, valve elements including a valve body and a valve defining said differential valve assembly, resilient means normally biasing said valve to a closed position with said valve body and opening in response to the force of pressurized fluid in said valve assembly opposing the biasing force of said resilient means, a nozzle defining orifices downstream from said valve, one of said valve elements including intersecting conical surfaces defining an adjoining line forming a valve seat seal when engaging the other of said elements when said valve is closed, said valve body and said valve defining a differential angle valve of a larger included angle between the conical surface of the valve body and the conical surface of the valve above said valve seat seal than the included angle between said valve body and said valve defined by the conical surface of said valve body and the conical surface of said valve downstream from said valve seat seal, the smaller included angle between said valve body and said valve downstream from said valve seat seal thereby causing the valve seat seal to migrate downstream from the initial valve seat seal due to wear of said valve body and said valve, means defining an annular groove on a conical surface downstream from the valve seat seal defining an upper edge for limiting the downward migration of said valve seat seal due to wear of said valve, and a lower edge as large as the nozzle passage downstream from said differential valve to retain throttling.