The disclosure provides a piston crown for a piston mountable in a combustion cylinder of an internal combustion engine. The piston crown includes a top annular surface. Radially inside the top annular surface is a piston bowl for guiding fuel injected into the combustion cylinder. The piston bowl includes a frusto-conical lip chamfer surface at a throat of the piston bowl next to the annular surface. In diametric cross-section the lip chamfer surface has a radius of at least 30 mm, preferably 30 mm.

Embodiments disclosed herein relate to internal combustion engines, combustion systems that include such internal combustion engines, and controls for controlling operation of the combustion engine. The internal combustion engine may include one or more mechanisms for injecting fuel, air, fuel-air mixture, or combinations thereof directly into one or more cylinders, and controls may operate or direct operation of such mechanisms.

The present invention relates to novel uses of copolymers for removing and/or reducing the level of deposits in the fuel system and/or injection system of direct injection diesel and/or gasoline engines.

Methods and systems are provided for an engine configured to deactivate at least some cylinders. In one example, an engine system may comprise a first group of cylinders having a first compression ratio and a second group of cylinders having a second compression ratio greater than the first.

Implementations are disclosed herein that relate to a cylinder occupying structure. An example provides a cylinder system comprising a mechanical cylinder including an internal space in which a fluid is introduced, and a piston configured for reciprocating motion in the internal space, and a cylinder occupying structure including an insertion rod acting as a second piston, wherein the insertion rod is variably inserted into, and retracted from, the internal space of the cylinder in correspondence with the reciprocating motion of the piston and where parts of the insertion rod and the piston may surround the combustion space.

Some embodiments described herein relate to a method of operating a compression ignition (CI) engine. The CI engine can include a combustion chamber. The method of operating the CI engine includes receiving a volume of intake charge in the combustion chamber, compressing the intake charge, injecting a volume of fuel into the combustion chamber, the fuel having a cetane number less than about 40, and combusting substantially all of the volume of fuel. A delay between injecting the volume of fuel into the combustion chamber and initiation of combustion is less than about 2 ms. The CI engine includes at least a two-stroke engine, an opposed-piston engine, a two-stroke opposed piston engine, a five-stroke engine, a six-stroke engine, a free-piston engine, a free piston engine linear, a rotary engine, and/or a Wankel rotary engine.

Disclosed is a fuel level estimation device including: an information acquiring unit acquiring information about a closed system internal pressure of a closed fuel vapor system including the fuel tank, a vent passage, and a canister; a flow rate controlling unit controlling, by actuating a negative pressure pump, a flow rate of fuel vapor-containing gas in the closed fuel vapor system; a fuel level estimating unit estimating a fuel level based on a total volume of the closed fuel vapor system and an occupied volume of the gas. The fuel level estimating unit estimates the occupied volume of the gas by using a change in a closed system internal pressure before and after the closed fuel vapor system is subjected to pressure-reducing treatment for a predetermined interval and a reference discharging rate when the gas is subject to the pressure-reducing treatment. An abnormality diagnostic apparatus is also disclosed.

A reentrant combustion chamber is disclosed. The reentrant combustion chamber includes a profile forming the inlet of the combustion chamber that is a projective surface formed inward in the combustion chamber and the bottom of the combustion chamber that is a recessed space that is recessed outward under the inlet in the combustion chamber, a cone formed in a truncated cone shape continuing from the profile and protruding to the central space in the combustion chamber, and a top end for expanding the space of the combustion chamber by expanding the top of the combustion chamber at the inlet of the combustion chamber.

Methods and systems for supplying fuel to a diesel engine during a cycle of a cylinder are described. In one example, a cylinder is supplied fuel via two fuel injectors having different fuel flow rates. The two fuel injectors may be arranged opposed to each other or in a way that fuel spray from one injector intersects and collides with fuel spray from the other injector.

Methods and systems for supplying fuel to a diesel engine during a cycle of a cylinder are described. In one example, a cylinder is supplied fuel via two fuel injectors having different fuel flow rates. The two fuel injectors may be operated to provide pilot, main, and post combustion fuel injections during a cycle of a cylinder.