Abstract: A direct injection engine includes an ignition assistance section applying energy to fuel injected into a cylinder using an injector to assist auto-ignition combustion of the fuel when the engine is within an auto-ignition combustion operation range. A start time of fuel injection is set within a period from a terminal stage of a compression stroke to a compression top dead center. The energy is applied to the fuel injected into the cylinder in a period from start of the fuel injection to an initial stage of an expansion stroke such that a time of a specific crank angle when an increase rate of in-cylinder pressure, which is a ratio of a change in the in-cylinder pressure to a change in a crank angle in motoring the engine, reaches a negative maximum value overlaps a combustion period when a combustion mass percentage of the fuel ranges from 10% to 90%.

Abstract: Disclosed is a heat-insulating structure which can be used, for example, to reduce the cooling loss of an engine. The heat-insulating structure includes a hollow particle layer made of a lot of hollow particles densely packed on a surface of a metallic base material. The hollow particle layer is covered with a coating.

Abstract: A direct injection engine includes an ignition assistance section applying energy to fuel injected into a cylinder using an injector to assist auto-ignition combustion of the fuel when the engine is within an auto-ignition combustion operation range. A start time of fuel injection is set within a period from a terminal stage of a compression stroke to a compression top dead center. The energy is applied to the fuel injected into the cylinder in a period from start of the fuel injection to an initial stage of an expansion stroke such that a time of a specific crank angle when an increase rate of in-cylinder pressure, which is a ratio of a change in the in-cylinder pressure to a change in a crank angle in motoring the engine, reaches a negative maximum value overlaps a combustion period when a combustion mass percentage of the fuel ranges from 10% to 90%.

Abstract: Disclosed is a heat-insulating structure which can be used, for example, to reduce the cooling loss of an engine. The heat-insulating structure includes a hollow particle layer made of a lot of hollow particles densely packed on a surface of a metallic base material. The hollow particle layer is covered with a coating.

Abstract: In forming a plating layer for a sliding portion, which comprises Cr that is electrolytically-deposited in a plating bath containing Cr, the plating bath contains organic sulfonic acid. Accordingly, micro-cracks are formed at the plating layer. The plating layer for a sliding portion has the superior low friction and lubricating property.

Abstract: In forming a plating layer for a sliding portion, which comprises Cr that is electrolytically-deposited in a plating bath containing Cr, the plating bath contains organic sulfonic acid. Accordingly, micro-cracks are formed at the plating layer. The plating layer for a sliding portion has the superior low friction and lubricating property.

Abstract: A rotor for rotary piston engines having flanks coated with coatings of a modified fluorine resin. The modified fluorine resin is prepared with a fluorine resin, such as tetrafluoroethylene resin, and a binder resin, such as epoxy resin. The coating layer is formed by applying the modified resin to the flank surface of the rotor and drying it at a low temperature to have the resin adhered to the flanks. The coating is heat-resistant and has an anti-peel-off property. The coating is softened during engine operation so that it can catch deposits of unburnt residual substances. The rotor is therefore effective to prevent carbon lock.