An engine is configured to ignite an air-fuel mixture with an electric spark to ignite an air-fuel mixture. The engine includes: a cylinder head including a chamber partition wall having through holes and defining a main combustion chamber and a sub-combustion chamber; a fuel injector that injects fuel into the main combustion chamber; an air injector that injects air into the sub-combustion chamber; an ignition device causes an electric discharge between an ignition electrode and the chamber partition wall; and a control system that controls the fuel and air injectors, and the ignition device. At a compression stroke during a warm-up operation, the fuel is injected throughout a first period, and the air is injected throughout a second period at least partially overlapping the first period. At a power stroke during the warm-up operation, the electric discharge is caused after the fuel is injected.

An engine is configured to ignite an air-fuel mixture with an electric spark to ignite an air-fuel mixture. The engine includes: a cylinder head including a chamber partition wall having through holes and defining a main combustion chamber and a sub-combustion chamber; a fuel injector that injects fuel into the main combustion chamber; an air injector that injects air into the sub-combustion chamber; an ignition device causes an electric discharge between an ignition electrode and the chamber partition wall; and a control system that controls the fuel and air injectors, and the ignition device. At a compression stroke during a warm-up operation, the fuel is injected throughout a first period, and the air is injected throughout a second period at least partially overlapping the first period. At a power stroke during the warm-up operation, the electric discharge is caused after the fuel is injected.

An engine includes: a piston including a cavity; a cylinder head configured so as to form a combustion chamber having a pent roof shape; a fuel injection valve configured to inject fuel from a second half of a compression stroke until a first half of an expansion stroke; and a spark plug arranged at a position corresponding to an upper side of the cavity. Injection openings which are arranged in a circumferential direction surrounding a longitudinal axis of the valve and through each of which the fuel is injected in a direction inclined relative to the longitudinal axis by a predetermined angle is formed such that when a height of a ceiling of the combustion chamber at a position corresponding to an edge end portion of the cavity in an injection direction of the injection opening is large, the injection angle of the injection opening is large.

An engine includes: a piston including a cavity; a cylinder head configured so as to form a combustion chamber having a pent roof shape; a fuel injection valve configured to inject fuel in a period from a second half of a compression stroke until a first half of an expansion stroke; and a spark plug arranged at a position corresponding to an upper side of the cavity. Injection openings which are arranged in a circumferential direction surrounding a longitudinal axis of the valve and through each of which the fuel is injected in a direction inclined relative to the longitudinal axis by a predetermined angle is formed such that when a height of a ceiling of the combustion chamber at a position corresponding to an edge end portion of the cavity in an injection direction of the injection opening is large, the injection angle of the injection opening is large.

An engine includes: a piston including a cavity; a cylinder head configured so as to form a combustion chamber having a pent roof shape; a fuel injection valve configured to inject fuel in a period from a second half of a compression stroke until a first half of an expansion stroke; and a spark plug arranged at a position corresponding to an upper side of the cavity. Injection openings which are arranged in a circumferential direction surrounding a longitudinal axis of the valve and through each of which the fuel is injected in a direction inclined relative to the longitudinal axis by a predetermined angle is formed such that when a height of a ceiling of the combustion chamber at a position corresponding to an edge end portion of the cavity in an injection direction of the injection opening is large, the injection angle of the injection opening is large.

An engine is configured to ignite an air-fuel mixture with an electric spark to ignite an air-fuel mixture. The engine includes: a cylinder head including a chamber partition wall having through holes and defining a main combustion chamber and a sub-combustion chamber; a fuel injector that injects fuel into the main combustion chamber; an air injector that injects air into the sub-combustion chamber; an ignition device causes an electric discharge between an ignition electrode and the chamber partition wall; and a control system that controls the fuel and air injectors, and the ignition device. At a compression stroke during a warm-up operation, the fuel is injected throughout a first period, and the air is injected throughout a second period at least partially overlapping the first period. At a power stroke during the warm-up operation, the electric discharge is caused after the fuel is injected.

An engine is configured to ignite an air-fuel mixture with an electric spark to ignite an air-fuel mixture. The engine includes: a cylinder head including a chamber partition wall having through holes and defining a main combustion chamber and a sub-combustion chamber; a fuel injector that injects fuel into the main combustion chamber; an air injector that injects air into the sub-combustion chamber; an ignition device causes an electric discharge between an ignition electrode and the chamber partition wall; and a control system that controls the fuel and air injectors, and the ignition device. At a compression stroke during a warm-up operation, the fuel is injected throughout a first period, and the air is injected throughout a second period at least partially overlapping the first period. At a power stroke during the warm-up operation, the electric discharge is caused after the fuel is injected.

The invention relates a process for all internal combustion engines types to control the pressure and/or the temperature inside the combustion chamber at the time of ignition of combustion, despite that the air/fuel mixture is maintained close of stoichiometry ratio. It mainly based on high compression by an auxiliary compressor of air. This air is accumulated in a reservoir. The purpose is to have two sources of compressed air with a large gape of temperature, where one source is relatively cold and corresponding to the ambient environment, and the other source is relatively hot, heated by the heat energy recovered from exhaust gases. The intake compressed air is carried out with predetermined quantity from both sources as an injection into the cylinder which contains part of the burnt gases from the previous combustion cycle, kept with predetermined quantity. This is possible because the engine operates with a two-stroke cycle.

The invention relates a process for all internal combustion engines types to control the pressure and/or the temperature inside the combustion chamber at the time of ignition of combustion, despite that the air/fuel mixture is maintained close of stoichiometry ratio. It mainly based on high compression by an auxiliary compressor of air. This air is accumulated in a reservoir. The purpose is to have two sources of compressed air with a large gape of temperature, where one source is relatively cold and corresponding to the ambient environment, and the other source is relatively hot, heated by the heat energy recovered from exhaust gases. The intake compressed air is carried out with predetermined quantity from both sources as an injection into the cylinder which contains part of the burnt gases from the previous combustion cycle, kept with predetermined quantity. This is possible because the engine operates with a two-stroke cycle.

A process relating to a two-stroke cycle internal combustion engine to control the pressure and/or the temperature of the gaseous blend inside the combustion chamber at the time of ignition of combustion, while the air/fuel mixture is maintained close to the stoichiometric ratio. The process is mainly based on high compression by an auxiliary compressor of air that is accumulated in a reservoir. The compressed air is typically injected at two different temperatures, one being relatively cold and the other being relatively hot, as heated by the heat energy recovered from exhaust gases or heaters. The intake compressed air is carried out with predetermined quantity from both temperatures as an injection into the cylinder which already contains a predetermined quantity of the burnt gases from the previous combustion cycle.