Abstract: A hydraulically driven piston pump and nozzle assembly for a high pressure fuel injection system is proposed, in particular one for Diesel engines, which has an assembly for raising the closing pressure for the purpose of accomplishing a rapid valve needle closing at the injection nozzle. The assembly substantially comprises a closing pressure chamber disposed in the region of the valve needle end remote from the valve seat, which chamber communicates via an overflow channel with an auxiliary pump chamber of an auxiliary pump piston which is driven together with the pump piston. At the termination of fuel delivery, fuel under increased pressure is conducted from the auxiliary pump chamber into the closing pressure chamber, from when this pressure is exerted, at least indirectly, upon the valve needle to cause an accelerated valve needle closing.

Abstract: Improvements in a fuel injection nozzle for internal combustion engines having a needle valve positioned in a chamber constrained by a closure spring positioned in another chamber thereabove, there also being provided an intermediate piston which includes a portion that extends into the spring chamber therebeneath and further includes a working surface area that is subjected to pressures in still another chamber positioned thereabove.