A two cycle-opposed piston, two cycle, homogenous charge compression ignition engine with cylinder sets, each cylinder set having a first cylinder with an intake port; a second cylinder coaxially aligned with the first cylinder and having an exhaust port; a first piston engaged within the first cylinder; a second piston engaged within the second cylinder; a combustion chamber formed between the first piston and the second piston; a first cam mechanically engaged with the first piston; a mechanical device to convert reciprocating motion to rotational motion connected to the second piston; and a charge pump connected to the intake port by an intake passage.

A two cycle-opposed piston, two cycle, homogenous charge compression ignition engine with cylinder sets, each cylinder set having a first cylinder with an intake port; a second cylinder coaxially aligned with the first cylinder and having an exhaust port; a first piston engaged within the first cylinder; a second piston engaged within the second cylinder; a combustion chamber formed between the first piston and the second piston; a first cam mechanically engaged with the first piston; a mechanical device to convert reciprocating motion to rotational motion connected to the second piston; and a charge pump connected to the intake port by an intake passage.

An engine control apparatus includes an ignition control section and an injection control section. When the partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of a expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. The energy of the preceding ignition is set to be higher when the in-cylinder pressure specified by the in-cylinder pressure specification section is high than when the in-cylinder pressure is low.

The invention is provided with an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of an expansion stroke to initiate SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes an injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Timing of the preceding ignition is set to be more retarded when an engine speed is high than when the engine speed is low.

A fuel injection control device for an engine is provided. A swirl generator generates a swirl flow inside a combustion chamber. A fuel injector with multiple nozzle holes injects fuel into the combustion chamber, and forms a lean mixture gas inside the combustion chamber. An spark plug ignites the lean mixture gas to cause the mixture gas to start combustion accompanied by flame propagation, and then combust by self-ignition. A first atomized fuel spray injected from a first nozzle hole and a second atomized fuel spray injected from a second nozzle hole separate from each other by the swirl flow. The fuel injector sequentially performs first and second injections in an intake stroke. A ratio of an injection amount of the second injection to the entire amount of fuel required per cycle is increased as an engine load increases.

An engine control apparatus includes an ignition control section and an injection control section. When the partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of a expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. The energy of the preceding ignition is set to be higher when fuel concentration specified by a fuel concentration specification section is low than when the fuel concentration is high.

An internal combustion engine includes a combustion chamber with a cylinder head, a cylinder, and a piston. The internal combustion engine also includes at least one intake valve and at least one exhaust valve that are connected to the combustion chamber, a fuel injector that injects fuel into the combustion chamber, at least two ignition devices arranged in the combustion chamber, and control means that control the valves, the injector, and the ignition means. The control means operate the engine according to different combustion modes including a controlled ignition combustion mode, a compression ignition combustion mode, and an assisted compression ignition combustion mode. The control means activate the ignition means in the assisted compression ignition combustion mode.

An engine system is provided, which includes a vehicle-mounted engine having an injector, a spark plug, and a property adjusting device, an accelerator opening sensor, and a controller. The controller performs a combustion control for controlling the injector, the spark plug, and the property adjusting device so that a target torque set based on a present accelerator opening detected by the accelerator opening sensor is outputted in a specific cycle in the future from a present time by a given delay time. In the combustion control, the controller sets a target load of the engine in the specific cycle based on the present accelerator opening, and sets a combustion transition from the present cycle to the specific cycle by selecting beforehand combustion from the present cycle to the specific cycle, from flame propagation combustion and compressed self-ignition combustion, based on the set target load.

An engine comprises a housing and a combustion assembly carried by the housing. The combustion assembly comprises an annular bore defined by the housing, at least one combustion piston disposed within the annular bore, and a sealing mechanism configured to selectively seal the at least one combustion piston relative to at least one corresponding wall of the annular bore. The engine comprises at least one rotary valve configured to move between a first position within the annular bore to allow the at least one combustion piston to travel within the annular bore from a first location proximate to the at least one valve to a second location distal to the at least one rotary valve and a second position within the annular bore to define a combustion chamber relative to the at least one combustion piston at the second location.

An engine control apparatus includes an ignition control section and an injection control section. When partial compression ignition combustion is carried out, the ignition control section causes an ignition plug to carry out: main ignition in which a spark is generated in a late period of a compression stroke or an initial period of a expansion stroke to initiate the SI combustion; and preceding ignition in which the spark is generated at earlier timing than the main ignition. Also, when the partial compression ignition combustion is carried out, the injection control section causes the injector to inject fuel at such timing that the fuel exists in a cylinder at an earlier time point than the preceding ignition. Energy of the preceding ignition is set to be lower when an in-cylinder temperature specified by an in-cylinder temperature specification section is high than when the in-cylinder temperature is low.