Fuel injection pump for internal combustion engines

Claim 1

In a fuel injection pump for internal combustion engines, including: (a) a housing; (b) a cylinder mounted within said housing and having a central bore and a plurality of fuel supplying bores formed about the circumference of said cylinder and extending substantially radially from said central bore; (c) a plurality of channel means within said housing, each extending between a fueL injection nozzle and a fuel supplying bore, said channel means and their operatively associated fuel supplying bores forming a plurality of fuel paths, one for each of the fuel injection nozzles, said plurality of fuel paths being equal in number to the number of engine cylinders supplied by said pump; (d) a piston, said cylinder and said piston defining a work chamber; (e) cam means for rotating and reciprocating said piston within said central bore; said piston serving, as a result of its motion within said central bore, to distribute fuel through respective ones of said plurality of fuel paths; (f) relief channel means defining a first control point; (g) relief valve means operatively associated with said relief channel means, said relief valve means being adapted to open during the fuel supply stroke of said piston, as a function of engine rpm and after the fuel supply to said fuel paths has been interrupted to thereby control the fuel pressure of the fuel quantity within said fuel paths, the improvement wherein: A. said relief channel means comprises two coaxially disposed blind bores within said piston and two radial bores one for each of said coaxially disposed blind bores, each said radial bore extending radially from the blind end of its respective blind bore; B. two fuel supplying bores are provided for each associated channel means with each of said radial bores being operatively associated with a respective one of each of said two fuel supplying bores, and with one of said radial bores and its operatively associated fuel supplying bores defining a second control point and the other of said radial bores and its operatively associated fuel supplying bores defining a third control point; C. said coaxially disposed blind bore closest to said work chamber and said third control point serving as a passage for supplying fuel to be distributed and as a passage through which fuel is distributed; and D. said coaxially disposed blind bore farthest from said work chamber and which extends between said first control point and said second control point including a spring-loaded valve which opens in the pressure relief direction.