Direct injection type diesel engine

Claim 1

A direct injection type Diesel engine, comprising: a combustion chamber having an inner wall surface formed at the head of a piston reciprocated in a cylinder of said Diesel engine; and fuel injection nozzle means mounted on a cylinder head of said Diesel engine at a position offset from the center of said combustion chamber, said fuel injection nozzle means being provided with a main nozzle hole for injecting a main fuel spray and an auxiliary nozzle hole for injecting an auxiliary fuel spray, said main nozzle hole being arranged and exposed to said inner wall of said combustion chamber and being directed toward the downstream side of fuel swirl with said chamber with respect to the location of said fuel injection nozzle means, said fuel swirl being generated in said combustion chamber in a manner to let said main fuel spray flow and evaporate on said inner wall surface of said combustion chamber along the stream of said swirl, said auxiliary nozzle hold being arranged and exposed to said inner surface of said combustion chamber at a position adjacent thereto, so as to allow said auxiliary fuel spray to collide with said inner wall surface of said combustion chamber at said position adjacent to said auxiliary nozzle hole, a portion of said auxiliary fuel spray being atomized so as to be scattered toward the inner area of said combustion chamber, while a residual part of said auxiliary fuel spray flows and evaporates along said inner wall surface of said combustion chamber, and wherein said fuel injection nozzle means injects fuel only through said auxiliary nozzle hole while keeping said main nozzle hole closed when said Diesel engine is under low load.