Present embodiments related to throttle body fuel injection systems intended to replace existing carburetors. More specifically, present embodiments relate to retrofitting carbureted engines with electronic fuel injection (EFI) which may be mounted on a manifold of an internal combustion engine and have bores of differing sizes and other characteristics which allow operation of such arrangement.

Low-cost fuel injection systems for internal combustion engines, including vapor fuel engines are provided.

A method and system for improving starting of an engine is presented. In one example, the method selects a first cylinder to receive fuel since engine stop the cylinder's position relative to the cylinder's top-dead-center compression stroke. The method also describes adjusting a number of fuel injections for a first combustion event since engine stop.

A method and system for improving starting of an engine is presented. In one example, the method selects a first cylinder to receive fuel since engine stop the cylinder's position relative to the cylinder's top-dead-center compression stroke. The method also describes adjusting a number of fuel injections for a first combustion event since engine stop.

An engine system in which blow-by gas with a specific gravity less than 1 with reference to air is generatable includes a cylinder block. The cylinder block includes a cylinder and a crank chamber which are arranged in an up/down direction, the crank chamber being positioned below the cylinder. An internal peripheral face of the cylinder block has a ventilation port that connects to a ventilation passage that connects an internal space of the crank chamber with an external space out of the cylinder block, and that is open. The ventilation port is placed above a center in the up/down direction in the crank chamber.

In a two-stroke engine including a scavenging port (43b) having an open end (42d) opening out in a side wall of the cylinder bore (3a) and communicating with a crank chamber (2a), the open end being configured to be closed and opened by the piston (22), a fuel injection device (71) is mounted on the engine main body so as to inject fuel onto a back side of the piston and/or a part of the side wall of the cylinder bore located under the piston via the open end of the scavenging port or via the open lower end of the cylinder bore. The fuel deposited on the surfaces of the piston and the cylinder inner wall promotes the cooling of such parts.

Present embodiments related to throttle body fuel injection systems intended to replace existing carburetors. More specifically, present embodiments relate to retrofitting carbureted engines with electronic fuel injection (EFI) which may be mounted on a manifold of an internal combustion engine and have bores of differing sizes and other characteristics which allow operation of such arrangement.

An engine system includes an engine housing having an intake port to convey an incoming flow of intake air to a first intake valve opening and a second intake valve opening located downstream of the first intake valve opening. A port fuel injector assembly is supported in the engine housing and includes a fuel injector within a sleeve and an outwardly opening fuel injection valve. The sleeve includes a fuel-directing cap extending into the intake port and forming a fuel injection opening defining an outgoing fuel path axis oriented at a fuel exit angle, to improve distribution of a gaseous fuel such as a gaseous hydrogen fuel to the respective intake valve openings for mixing and combustion in an engine cylinder. Related apparatus of a port fuel injector assembly and methodology is also disclosed.