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.

In internal combustion engine, a fuel injector has a nozzle tip forming first and second pluralities of nozzle openings configured to inject respective pluralities of first and second fuel jets into a combustion chamber. The first fuel jets are directed between projections formed in a piston during a main injection, and the second fuel jets are directed towards the protrusions during a post injection. The protrusions are asymmetrical to redirect the first fuel jets.

A method for operating an internal combustion engine including a step of concurrently introducing at least two combustible fuel jets into a combustion chamber of an internal combustion engine. A first combustible fuel jet of the at least two combustible fuel jets is ignited at an ignition time point. In a first operating mode of the internal combustion engine a second combustible fuel jet which is different from the first combustible fuel jet of the at least two combustible fuel jets is ignited after the ignition time point.

A method for operating an internal combustion engine having at least two cylinders and having a single injector for central point injection of fuel into an air intake connected to the cylinders, wherein for each of the cylinders an injection quantity of the fuel and a starting time of the injection are specified and set as a function of the present engine load and the present engine speed. The invention further relates to such an internal combustion engine.

A control device for an engine is provided, which includes a combustion controlling module, and an ignition retard determining module configured to determine whether there is a request for an ignition retard for retarding an ignition timing of an ignition plug. When the controlling module controls the ignition plug and an injector so that the SPCCI combustion is performed and there is not the ignition retard request, the controlling module executes a control in which the entire fuel to be injected in one cycle is injected in an intake stroke and a jump-spark ignition is carried out at a basic ignition timing, and when there is the ignition retard request, the controlling module executes a control in which an injection is performed in an intake stroke, a portion of the entire fuel is injected in a compression stroke, and the ignition timing is retarded from the basic ignition timing.

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 therebetween. 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 load is lower than the load in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller sets the timing of the pilot injection(s) so that the distribution ratio of the fuel spray of the pilot injection(s) for the lower cavity is higher when the engine operates in the first state than when in the second 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 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 load is lower than the load in the first state. The fuel spray is distributed to the lower cavity and the upper cavity. The controller outputs a control signal to a fuel injection valve so that a distribution ratio for the upper cavity is higher when the engine operates in the second state than when in the first state.

A combustion chamber comprising an upstream end wall, at least one annular wall, at least one fuel injector and at least one seal. The at least one annular wall being secured to the upstream end wall. The upstream end wall having at least one aperture. Each fuel injector being arranged in a corresponding one of the apertures in the upstream end wall and each seal being arranged in a corresponding one of the apertures in the upstream end wall and around the corresponding one of the fuel injectors. Each seal having an inner surface facing the corresponding one of the fuel injectors and an outer surface facing away from the corresponding one of the fuel injectors. Each seal abutting the corresponding one of the fuel injectors. The downstream end of each seal increasing in diameter in a downstream direction and the upstream end of each seal having a radially extending flange. Each seal having a plurality of coolant apertures extending axially through the radially extending flange and/or each seal having a plurality of thermal conductors extending axially from the radially extending flange to the downstream end of the seal.

A two-stroke opposed piston internal combustion engine including a plurality of cylinders, each cylinder being provided with a first piston and a second piston adapted to perform opposed motions in the cylinder, each cylinder being provided with at least one intake port, a communication between an air intake arrangement and the cylinder via the intake port being dependent on the position of the first piston, each cylinder further being provided with at least one exhaust port, a communication between an exhaust guiding arrangement and the cylinder via the exhaust port being dependent on the position of the second piston, at least one of the cylinders being provided with an additional port and an additional port valve, a communication between the cylinder and an additional conduit externally of the cylinder, via the additional port, being controllable with the additional port valve, the air intake arrangement including at least one intake valve for selectively reducing or inhibiting air admittance to at least one of the cylinders.

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.