A piston for an internal combustion engine is disclosed. The piston is configured to reciprocate along a centre axis of the piston during operation in an engine. The piston comprises a number of fuel directing surfaces arranged at a distance from a top surface of the piston measured along the centre axis . Each fuel directing surface is configured to direct a fuel spray sprayed onto the fuel directing surface. The fuel directing surfaces are arranged with gaps between two adjacent fuel directing surfaces. The present disclosure further relates to an engine comprising a piston and a vehicle comprising an internal combustion engine.

A piston crown for a piston of an internal combustion engine, the piston crown comprising an annular surface at a first end of the piston crown; and a recessed piston bowl. The piston bowl comprises: a raised floor in the center of the piston bowl; an arcuate surface located radially outward relative to the raised floor; and a lip chamfer surface extending from the arcuate surface to the annular surface. A radially inmost portion of the lip chamfer surface is radially inside the outermost portion of the arcuate surface. The radial distance between the center axis and the innermost edge of the annular surface is between 2.3 and 3.2 time the bowl height. The acute angle between a line extending in the radial direction and a line tangent to the arcuate surface closest to the first end of the piston crown is between 40 and 80 degrees.

A steel piston with an engineered coating is provided. A high thermal conductivity material, for example copper, is disposed on first regions of a combustion bowl to reduce hot spots in the piston. A low thermal conductivity material, for example a ceramic, is disposed on second regions of the combustion bowl to reduce loss of heat through the piston. The high thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 5 μm to help reflect IR radiation and promote fuel flow. The low thermal conductivity material disposed on the combustion bowl has a surface roughness (R.sub.a) of less than 3 μm to promote fuel flow. The low thermal conductivity material is also disposed on the bowl rim and top ring land, and has a surface roughness (R.sub.a) of greater than 8 μm on the bowl rim and top ring land to retard gas flow.

In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston of the engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. A controller causes a main injection and at least one pilot injection to be executed when an engine operates in a first state and a second state in which the speed is higher than the speed in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller maintains an injection amount of the main injection and increases an injection amount of the pilot injection(s) when the engine operates in the second state as compared to when the engine operates in the first state.

In a compression-ignition engine having a two-stage cavity, the distribution ratio between fuel for an upper cavity and fuel for a lower cavity is maintained even when the operational state of the engine changes. A piston of the compression-ignition engine includes a lower cavity, an upper cavity, and a lip portion between the lower cavity and the upper cavity. A controller causes a main injection and at least one pilot injection to be executed when the engine operates in a first state and a second state in which the speed is higher than the speed in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller increases an injection amount per pilot injection when the engine operates in the second state than when the engine operates in the first state.

A diesel engine includes at least one cylinder (1) with a piston (2) having a piston bowl (3). A fuel injector (6) is configured to direct a fuel spray towards a target area (21) on an annular wall section (22) of the piston bowl so as to make a flame (20) formed by ignition of the fuel spray hit the target area. The target area borders, via a flow separation edge (23), on a lowered flow separation area (24) on the annular wall section so as to give this annular wall section a stepped configuration. The flow separation edge and flow separation area are configured to induce the formation of a vortex-filled wake between the flame and the flow separation area on the downstream side of the flow separation edge when the flame flows from the target area, across the flow separation edge and over the flow separation area.

A piston for an internal combustion engine is disclosed. The piston comprises a number of fuel directing surfaces for directing a fuel spray sprayed onto the fuel directing surface. At least one of the fuel direction surfaces is/are inclined relative to a tangential direction of the piston. The present disclosure further relates to an engine comprising a piston and a vehicle comprising an internal combustion engine.

This piston for a diesel engine includes: a bottom portion that has a deepest combustion chamber bottom in the combustion chamber; a circumferential protrusion that is provided around an entire circumference of a circumferential wall between the bottom portion and a top surface of the piston and protrudes toward an intersection (P0) of a center line of the piston and the top surface in a cross-sectional view that includes the center line; an inclination portion that inclines closer to the top surface toward an outer side in a radial direction from the circumferential protrusion; and a rising portion that rises from the inclination portion toward the top surface.

A neat-fuel direct-injected compression ignition engine having a thermal barrier coated combustion chamber, an injection port injects fuel that satisfies a stoichiometric condition with respect to the intake air, a mechanical exhaust regenerator transfers energy from exhaust gas to intake compression stages, an exhaust O.sub.2 sensor inputs to a feedback control to deliver quantified fuel, a variable valve actuation (VVA) controls valve positions, an exhaust gas temperature sensor controls exhaust feedback by closing the exhaust valve early according to the VVA, or recirculated to the chamber with an exhaust-gas-recirculation (EGR), heat exchanger, and flow path connecting an air intake, a load command input, and a computer operates the EGR from sensors to input exhaust gas according exhaust temperature signals and changes VVA timing, the load control is by chamber exhaust gas, the computer operates a fuel injector to deliver fuel independent of exhaust gas by the O.sub.2 signals.

Systems, devices, and methods described herein provide one or more radical chemicals generators (RCGs) and/or mini-chambers (M-Cs) that can be used to provide enhanced radical ignition (ERI) in an internal combustion engine. RCGs as described herein can include quenching systems (QSs) that can be configured to quench a flame of combustion products to produce a jet of partial combustion products containing radical species (RS). The jet of partial combustion products can be injected to a main combustion chamber (MCC) of an engine to induce ERI. ERI can proceed under leaner fuel conditions and lower temperatures compared to those needed for conventional thermally induced, fuel oxidation chain initiation reaction processes.