Systems are provided for cooling combustion chamber gasses and increasing an amount of air entrained in an injected fuel spray. In one example, a cooling passage may be included in an internal combustion engine, the cooling passage positioned exterior to a cylinder bore of the engine and coupled to the cylinder bore at a first opening and a second opening. The cooling passage may receive gasses from the cylinder bore via the first opening, and may cool the gasses as they travel through the cooling passage before returning the gasses to the cylinder bore via the second opening.

Disclosed is a combustion system design method based on a target heat release rate, which belongs to the technical field of diesel engine combustion chamber design. The method includes: obtaining an ideal heat release rate based on Sabathe-Miller cycle; simulating the ideal heat release rate based on a double-Wiebe function and obtaining the target heat release rate; constructing a mapping relation among the heat release rate, piston geometric parameters and fuel injection parameters, which includes target start of combustion being an function of fuel injection timing and ignition delay, premixed combustion parameters being functions of throat radius, injection pressure and nozzle diameter, and diffusion combustion being a function of piston pit depth; solving target piston geometric parameters and target fuel injection parameters based on the mapping relation; and then designing a combustion system. The method does not depend on experience and multi-scheme design, greatly shortens the combustion system design.

An auto-ignition engine system is provided. The auto-ignition engine system includes a cylinder having an intake valve and an exhaust valve coupled thereto, an opening in a cylinder head defining a portion of the boundary of the cylinder, a glow plug heating element extending through the opening into the cylinder, an insert at least partially surrounding a glow plug heating element and coupled thereto, and an adjustment mechanism configured to alter the position of the glow plug heating element and the insert in the cylinder.

A diesel engine of the present invention includes a turbocharger including: a turbine provided on an exhaust passage; a compressor provided on an intake passage; and a plurality of nozzle vanes provided around the turbine to control a flow velocity of an exhaust gas colliding with the turbine, angles of the nozzle vanes being changeable. In a case where a ratio of a volume of a combustion chamber when the intake valve is closed to a volume of the combustion chamber when a piston is located at a top dead center is denoted by an effective compression ratio ε.sub.e, and a total displacement of the engine is denoted by V (L), the effective compression ratio ε.sub.e is set to satisfy Formula (1) “−0.67×V+15.2≦ε.sub.e≦14.8.”

A piston for a reciprocating piston machine includes a piston crown, a piston recess, and an annular groove formed in the piston crown. The annular groove extends in a radial direction of the piston outwards and a cross-section of the annular groove has a half-teardrop shape. The half-teardrop shape has a first radius and a second radius where the second radius is directly contiguous with the first radius outwards in the radial direction of the piston and where the second radius is greater than the first radius.

A method for operating an internal combustion engine of a motor vehicle having a cylinder, the combustion chamber of which is delimited in the radial direction by a cylinder wall and in the axial direction by a piston and by a combustion chamber roof. The piston has an annularly peripheral piston stage which is arranged axially recessed in the piston compared with an annularly peripheral piston crown and which merges via an annularly jet splitter contour into a piston hollow arranged axially recessed in the piston in relation to the piston stage. An injector is allocated to the cylinder and via the injector several injection jets are simultaneously injected directly into the combustion chamber in a star shape for a combustion process.

A two-stroke internal combustion engine includes a diversion fin and an allowance slot. The diversion fin is a structure that has flanges at two ends and a rectangular longitudinal cross section profile. The diversion fin is clamped by a cylinder head and a cylinder block. The diversion fin extends along the diameter direction of the cylinder head and is positioned between an air inlet channel and an air exhaust channel. The diversion fin separates the air inlet channel from the air exhaust channel. The upper end of the diversion fin is provided with a transverse through groove at a position corresponding to an oil nozzle of an oil injector. The allowance slot is disposed on a piston and is positioned in the center of a combustor. The position of the allowance slot corresponds to the position of the diversion fin.

A galleryless piston having a reduced weight and a reduced operating temperature is provided. The piston includes an undercrown surface exposed from an underside of the piston, a ring belt, pin bosses each presenting a pin bore, and skirt panels depending from the ring belt and coupled to the pin bosses by strut. The piston further includes an inner undercrown region extending along the undercrown surface and surrounded by the skirt panels, the struts, and the pin bosses. The piston also includes outer pockets each extending along the undercrown surface and each surrounded by a portion of the ring belt, one of the pin bosses, and the struts coupling the one pin boss to the skirt panels. Cutouts are located in the pin bosses above the pin bores to increase the area of the undercrown surface and thus allow cooling oil to remove more heat from the undercrown surface.

An internal combustion engine system includes an engine housing having a combustion cylinder, and a piston movable within the combustion cylinder to increase a pressure therein to an autoignition threshold for injected fuel. The piston includes a piston crown having a combustion face forming a combustion bowl, and varied in profile to form jet-jet interaction limiters at locations offset from fuel spray jet paths from a fuel injector. The jet-jet interaction limiters include a bowl component and a step component protruding, respectively, within the combustion bowl and a step located transitioning between the combustion bowl and a circumferential rim of the piston. Limiting jet-jet interaction limits soot production in exhaust produced by the engine.

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.