Direct injection diesel engine

摘要

A combustion chamber ( 20 ) opening toward a cylinder head ( 5 ) is provided on a top surface ( 11 ) of a piston ( 10 ), and this combustion chamber ( 20 ) comprises a first volume ( 22 ) having an inclined surface ( 20 ) and a second volume ( 23 ) further recessed from the first volume ( 22 ) toward a pin boss ( 13 ). Fuel spray F from a fuel injection nozzle ( 9 ) is injected toward an inner peripheral wall section ( 24 ) of the second volume ( 23 ) in a former stage of fuel injection and toward the inclined surface ( 21 ) of the first volume ( 22 ) in a later stage of fuel injection, and the percentage of the fuel injection period in the former stage against the total fuel injection period is set to the range from 40% to 70%.