Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

Provided is an internal combustion engine control device capable of reducing a measurement load and calculating a flow velocity around an ignition plug. The internal combustion engine control device includes an inter-gap voltage calculation unit 31 and a flow velocity calculation unit 32. The inter-gap voltage calculation unit 31 calculates a reference inter-gap voltage under a reference condition, based on a secondary current and in-cylinder pressure. The flow velocity calculation unit calculates the flow velocity of a gas around the ignition plug based on the reference inter-gap voltage.

An electron generation means for generating electrons includes a rectifier circuit and a booster circuit. AC power from a power supply is passed through the rectifier circuit in advance and then flown to the booster circuit. The rectifier circuit, according to the plus/minus inversion cycle of the said AC power, blocks current flowing toward a second terminal in a state where a first terminal of the rectifier circuit has a positive potential, and current flows from the second terminal only in the state where the first terminal of the rectifier circuit has a negative potential, and thus current flows only in one direction of the alternating current. The booster circuit boosts the voltage on a primary side, and electrons are generated from one terminal on a secondary side of the booster circuit only in a state where the first terminal of the rectifier circuit has a negative potential.

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.

Among multiple scavenging passages 14 included in a cylinder, a scavenging passage connected to at least one scavenging port 16 constitutes a variable scavenging passage 14(ch). An upper end portion of the variable scavenging passage 14(ch) has a guide surface 50 defining a discharge direction of a scavenging gas discharged from a variable scavenging port 16(ch) connected thereto on a horizontal plane. The guide surface 50 includes at least a first guide portion 50(H) defining a first discharge direction of the scavenging gas and a second guide portion 50(L) defining a second discharge direction of the scavenging gas. The discharge direction of the scavenging gas is changed from the first discharge direction to the second discharge direction on the horizontal plane by the first and second guide portions 50(H) and 50(L) in the scavenging stroke.

A two-stroke engine piston (1) is disclosed comprising a piston top (3), a mantle surface (5), a stratified scavenging channel (7) in the mantle surface (5), and a weight reduction space (9) arranged between the piston top (3) and the stratified scavenging channel (7). The weight reduction space (9) has a largest first axial extent (a1) at the mantle surface (5) and a second axial extent (a2) radially inside the mantle surface (5), and wherein the second axial extent (a2) is greater than the largest first axial extent (a1). The present disclosure further relates to an engine (30), a hand-held tool (40), and a method of manufacturing an engine piston (1).

A two-stroke engine piston (1) is disclosed comprising a piston top (3), a mantle surface (5), a stratified scavenging channel (7) in the mantle surface (5), and a weight reduction space (9) arranged between the piston top (3) and the stratified scavenging channel (7). The weight reduction space (9) has a largest first axial extent (a1) at the mantle surface (5) and a second axial extent (a2) radially inside the mantle surface (5), and wherein the second axial extent (a2) is greater than the largest first axial extent (a1). The present disclosure further relates to an engine (30), a hand-held tool (40), and a method of manufacturing an engine piston (1).

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 two-stroke engine includes: a scavenging port communicating with a crank chamber and a side portion of a cylinder, and switchably brought into communication with or shut off from the cylinder by a piston; and multiple fuel injection valves for injecting fuel into the scavenging port. Since the fuel injection valves inject fuel into the scavenging port, there is no need to apply a high pressure injection system. By causing the start of fuel injection to be delayed from a timing at which the scavenging port is opened, fresh air is sent into the cylinder at an early stage of scavenging, and air-fuel mixture is sent into the cylinder at a late stage of scavenging. Thereby, even in a long-stroke engine, stratified scavenging is performed to suppress blow-by of air-fuel mixture.

Fuel management system for enhanced operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder. It is preferred that the direct injection occur after the inlet valve is closed. It is also preferred that stoichiometric operation with a three way catalyst be used to minimize emissions. In addition, it is also preferred that the anti-knock agents have a heat of vaporization per unit of combustion energy that is at least three times that of gasoline.