An object of the present invention is to, while forming a heat insulating layer on a squish area surface of a top surface of a piston main body, prevent generation of large cracks on the heat insulating layer and suppress damages and peeling of the heat insulating layer. To achieve this object, in the present invention, pressure is applied to a heat insulating layer provided on a top surface of a piston main body, that is, a pressing stress is applied to the heat insulating layer in advance.

A thermal insulation film is formed on a bottom surface of a cylinder head facing a top surface of a piston. The thermal insulation film in a region (a circumferential region) of a bottom surface of the cylinder head configuring a squish area in a circumferential edge of a cavity region is formed to be thinner than the thermal insulation film in a region (a cavity region) of the bottom surface of the cylinder head facing a cavity. The thermal insulation film in the circumferential region is polished, and surface roughness thereof is equal to or lower than 3 μm. The thermal insulation film in the cavity region is not polished, and surface roughness thereof is 3 to 8 μm on average.

A piston capable of reducing undesirable “knock,” reducing hydrocarbon emissions, and providing more complete combustion, is provided. The piston includes a multilayer coating having a thickness of 500 microns or less disposed on an upper combustion surface. The coating includes a bond layer including nickel disposed on the upper combustion surface. A thermal barrier layer including a ceramic composition is disposed on the bond layer. A sealant layer formed of metal is disposed on the thermal barrier layer. A catalytic layer including at least one of platinum, ruthenium, rhodium, palladium, osmium, and iridium is disposed on the sealant layer. The catalytic layer can be disposed on select regions or the entire upper combustion surface to promote combustion through a catalyzed reaction.

The present disclosure relates to a piston for an internal combustion engine. The piston comprises a cover which at least partially covers a piston basehead of the piston. A heat-isolating air gap is formed between the cover and the piston basehead, which is fluidically connected to a combustion chamber and/or an upper side of the cover facing away from the heat-isolating air gap. The fluidic connection permits a fluid exchange to take place between the heat-isolating air gap and the combustion chamber. In this way, a pressure gradient can be reduced between the combustion chamber and the heat-isolating air gap. As a result, the cover is/can be kept thin without being deformed during combustion.

The present disclosure relates to a piston for an internal combustion engine. The piston comprises a cover which at least partially covers a piston basehead of the piston. A heat-isolating air gap is formed between the cover and the piston basehead, which is fluidically connected to a combustion chamber and/or an upper side of the cover facing away from the heat-isolating air gap. The fluidic connection permits a fluid exchange to take place between the heat-isolating air gap and the combustion chamber. In this way, a pressure gradient can be reduced between the combustion chamber and the heat-isolating air gap. As a result, the cover is/can be kept thin without being deformed during combustion.

The fuel injection timing IT is changed based operation and environmental condition of the engine. If the injection timing IT is changed, the rate of fuel passing through meshes of the mesh member (i.e., the mesh passing rate) changes. If the mesh passing rate changes, the set-off position (i.e., the ignition position of the air-fuel mixture) is extended or shortened. Based on this, under the condition of high ignition performance (i.e., the second condition), the mesh passing rate is controlled to increase thereby the set-off position is extended. On the other hand, under the condition of low ignition performance (i.e., the first condition), the mesh passing rate is controlled to decrease thereby the extension of the set-off position is suppressed or prohibited.

A combustion system includes a remodeled diesel engine and a fuel composition to be added into the remodeled diesel engine. The remodeled diesel engine includes a cylinder unit, and a coating coated on the cylinder unit and containing a catalyst that is a metal, an alloy of the metal, a composite containing oxides of the metal, a salt of the metal or combinations thereof. The metal is platinum, nickel, cobalt, copper, molybdenum, and/or titanium. The fuel composition includes water, a fuel oil and an emulsifying agent. The amount of water ranges from 10 to 90 wt % based on total weight of water and the fuel oil, and the amount of the emulsifying agent ranges from 0.5 to 10 wt % relative to total weight of water and the fuel oil.

A piston for a cylinder for an internal combustion engine has a piston bowl surface adapted for facing a combustion chamber of the cylinder, the piston bowl surface being provided with a thermal barrier coating layer, wherein the thermal barrier coating layer is provided on a plurality of circumferentially spaced surface parts of the piston bowl surface. A method for producing a piston for a cylinder for an internal combustion engine includes the steps of providing a piston for a cylinder for an internal combustion engine, the piston having a piston bowl surface adapted for facing a combustion chamber of the cylinder, and providing the piston bowl surface with a thermal barrier coating layer, wherein the step of providing the thermal barrier coating layer is made on a plurality of circumferentially spaced surface parts of the piston bowl surface.

A combustion system includes a remodeled diesel engine and a fuel composition to be added into the remodeled diesel engine. The remodeled diesel engine includes a cylinder unit, and a coating coated on the cylinder unit and containing a catalyst that is a metal, an alloy of the metal, a composite containing oxides of the metal, a salt of the metal or combinations thereof. The metal is platinum, nickel, cobalt, copper, molybdenum, and/or titanium. The fuel composition includes water, a fuel oil and an emulsifying agent. The amount of water ranges from 10 to 90 wt % based on total weight of water and the fuel oil, and the amount of the emulsifying agent ranges from 0.5 to 10 wt % relative to total weight of water and the fuel oil.

The invention discloses a method for producing an internal combustion engine piston having at least one cavity which is filled with an alkali metal cooling medium and is subsequently closed. The at least one cavity longitudinally extends from a central point into the piston body toward the piston circumference. The invention further discloses a piston produced according to the method.