The present invention is to prevent mixing of fresh air and an air-fuel mixture when a throttle valve is fully opened and increase a delivery ratio. A main nozzle (30) is surrounded by a tunnel-like air flow guiding member (52). The air flow guiding member (52) is opened at its front and back sides. A whole amount of fuel discharged via a main nozzle (30) is sent to a downstream side by an air flow created by the air flow guiding member (52). When a throttle valve (22) and a choke valve (24) are both in a fully-opened state, fresh air flows into an air-fuel mixture passage (12) through a gap between these valves (22, 24).

The present invention is to prevent mixing of fresh air and an air-fuel mixture when a throttle valve is fully opened and increase a delivery ratio. A main nozzle (30) is surrounded by a tunnel-like air flow guiding member (52). The air flow guiding member (52) is opened at its front and back sides. A whole amount of fuel discharged via a main nozzle (30) is sent to a downstream side by an air flow created by the air flow guiding member (52). When a throttle valve (22) and a choke valve (24) are both in a fully-opened state, fresh air flows into an air-fuel mixture passage (12) through a gap between these valves (22, 24).

A suction tube of a stratified scavenging engine that can improve the flexibility in designing the shapes and layouts of an air-fuel mixture passage and an air passage; allow for continuous and smooth changes in the shapes of the cross sections of the air-fuel mixture passage and the air passage from the inlet side toward the outlet side; reduce the number of components; and facilitate attachment and assembly; and that is also advantageous in terms of cost is provided. The suction tube includes an air-fuel mixture passage and an air passage, inlet and outlet sides of the passages being connected to a carburetor and a cylinder, respectively; a cylindrical exterior member that mainly forms an outer perimeter portion of each of the air-fuel mixture passage and the air passage; and an interior member for dividing the inside of the cylindrical exterior member into the air-fuel mixture passage and the air passage. With the use of elastic deformation of the interior member or the cylindrical exterior member, the interior member is attached to and integrally formed with the inside of the cylindrical exterior member.

A piston for an engine is provided. The piston includes a body having a crown disposed about a central axis. The crown includes an inner circumference and an outer circumference. The piston includes a central chamber transversely disposed within the body and recessed with respect to the crown. The piston includes a central mound disposed within the central chamber about the central axis. The piston also includes a bowl extending from the central mound towards the crown. The piston further includes a passageway provided on the inner circumference of the crown. The passageway includes a slot defined by a first surface inclined at a first angle with respect to the central axis. The slot is adapted to allow flow of a fuel from the central chamber towards the outer circumference of the crown.

Fuel management system for efficient operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder of the engine. A fuel management microprocessor system controls injection of the anti-knock agent so as to control knock and minimize that amount of the anti-knock agent that is used in a drive cycle. It is preferred that the anti-knock agent is ethanol. The use of ethanol can be further minimized by injection in a non-uniform manner within a cylinder. The ethanol injection suppresses knock so that higher compression ratio and/or engine downsizing from increased turbocharging or supercharging can be used to increase the efficiency or the engine.

A direct injection diesel engine is provided with a fuel injection nozzle which is capable of performing a multistage injection. In a middle-or-high load region, in order to decrease soot, an after-injection is performed immediately after a main injection. In a case of fuel with a low Cetane number, the after-injection can cause a worsening of soot. Hence, an ignition delay interval (period of time) of the main injection is determined. In a case where the ignition time delay interval (period of time) is equal to or above a threshold value, the after-injection is inhibited.

A fuel supply system for a reciprocating-piston engine includes a storage tank; a wall of the storage tank defining a first aperture and a second aperture therethrough; a first fuel injector fluidly coupled with the first aperture of the storage tank via a pressure control module and a first fuel injector supply conduit; a pump fluidly coupled with the second aperture of the storage tank; and a second fuel injector fluidly coupled with an outlet port of the pump via a second fuel injector supply conduit. The pressure control module is configured to maintain a pressure in the first fuel injector supply conduit within a pressure range that includes a pressure value that is less than a pressure inside the storage tank. The pump is configured to maintain a pressure inside the second fuel injector supply conduit that is greater than the pressure inside the first fuel injector supply conduit.

A fuel supply system for a reciprocating-piston engine includes a storage tank; a wall of the storage tank defining a first aperture and a second aperture therethrough; a first fuel injector fluidly coupled with the first aperture of the storage tank via a pressure control module and a first fuel injector supply conduit; a pump fluidly coupled with the second aperture of the storage tank; and a second fuel injector fluidly coupled with an outlet port of the pump via a second fuel injector supply conduit. The pressure control module is configured to maintain a pressure in the first fuel injector supply conduit within a pressure range that includes a pressure value that is less than a pressure inside the storage tank. The pump is configured to maintain a pressure inside the second fuel injector supply conduit that is greater than the pressure inside the first fuel injector supply conduit.

Fuel management system for efficient operation of a spark ignition gasoline engine. Injectors inject an anti-knock agent such as ethanol directly into a cylinder of the engine. A fuel management microprocessor system controls injection of the anti-knock agent so as to control knock and minimize that amount of the anti-knock agent that is used in a drive cycle. It is preferred that the anti-knock agent is ethanol. The use of ethanol can be further minimized by injection in a non-uniform manner within a cylinder. The ethanol injection suppresses knock so that higher compression ratio and/or engine downsizing from increased turbocharging or supercharging can be used to increase the efficiency or the engine.

Systems and methods are provided for operation of fuel injectors within an applied-ignition, direct-injection internal combustion engine. In one example, a needle of a fuel injector is moved from a retracted position to an extended position relative to a plurality of injection holes of a nozzle of the fuel injector, with at least one injection hole being separated from a fuel supply system earlier than each other injection hole. In a partially retracted position, fuel flow along a first side of the needle is decreased relative to fuel flow along a second side of the needle.