Patent ID: 8156927
Filing Date: 2012-04-17
Classification: F02B,Y02T

Abstract:
1. A combustion chamber structure for a direct injection diesel engine having a cavity on a top surface of a piston, said cavity being concave to provide a majority of the combustion chamber, fuel being injected from a center of a cylinder top radially into said cavity to self-ignite, said combustion chamber structure comprising: a depression at an outer periphery of open of the cavity, said depression being sunken by a required depth relative to the top surface of the piston to provide a step, said depression having a bottom with an outer periphery gradually rising radially outwardly in modestly curved surface to the top surface of the piston such that an inlet lip is formed at a position lower than the top surface of the piston by an inner periphery of the bottom of said depression and a combustion chamber wall rising from a bottom of the cavity, wherein a width of the depression in a radial direction is at least 9% and at most 19% of a diameter of the inlet lip, a depth of the inlet lip relative to the top surface of the piston is at least 4.5% and at most 9.5% of the diameter of the inlet lip, a nozzle cone angle for fuel injection is in a range of 140°-160°, and atomized fuel flows around the inlet lip at least in an early phase of the injection.