A simple engine, comprises (1) a cylinder, and a spark plug in the cylinder; (2) a carburetor, fluidly connected to the cylinder; (3) a primary air intake path, fluidly connecting atmosphere to the carburetor; (4) a carburetor bypass air intake path, fluidly connecting air to the cylinder without passing through the carburetor; and (5) a valve, along the carburetor bypass air intake path, for controlling the flow of air through the carburetor bypass air intake path.

An automatic starting system includes a choke or similar apparatus. The apparatus includes at least a choke plate, a choke arm, and a control arm. The choke plate is configured to control a ratio of fuel and air for an engine. The choke arm is fixedly coupled with the choke plate. The control arm adjustably coupled with the choke arm. The control arm and the choke arm cooperate to move the choke plate into multiple positions, which correspond to multiple ratios of fuel and air for the engine.

An automatic starting system includes a choke or similar apparatus. The apparatus includes at least a choke plate, a choke arm, and a control arm. The choke plate is configured to control a ratio of fuel and air for an engine. The choke arm is fixedly coupled with the choke plate. The control arm adjustably coupled with the choke arm. The control arm and the choke arm cooperate to move the choke plate into multiple positions, which correspond to multiple ratios of fuel and air for the engine.

A fuel supply device includes a main body, fuel chamber, fuel supply pipe and a fuel valve. The main body has a main bore with an inlet for air and an outlet through which a fuel and air mixture flows. The fuel chamber retains a supply of fuel. The fuel supply pipe has a passage communicating with the main bore and through which fuel from the fuel chamber flows to the main bore. And the fuel valve has a valve seat, a valve element movable relative to the valve seat between an open position and a closed position, an inlet upstream of the valve seat and is in communication with the fuel chamber, and an outlet downstream of the valve seat. The outlet is coaxially aligned with the passage of the fuel supply pipe and the fuel valve is electrically operated to move the valve element.

The invention relates to a fuel-metering arrangement for the mixture-forming unit (2) of an internal combustion engine (10) in a portable handheld work apparatus. The mixture-forming unit comprises a fuel store (30), a switchable valve (40) and a fuel channel (20) which opens into an intake region of the engine (10). The valve (40) has an inflow port (41) which is connected to the fuel store (30) and an outflow port (42) which is connected to the fuel channel (20). A fuel column is mechanically moved by the switching of the valve. In order to compensate for this fuel column, the outflow port (42) is connected via a bypass channel (45) to the inflow port (41) and a flow valve (46) is mounted in the bypass channel (45). The flow valve (46) opens in flow direction (49) from the outflow port (42) to the inflow port (41) and blocks in the direction opposite thereto.

The invention relates to a fuel-metering arrangement for the mixture-forming unit (2) of an internal combustion engine (10) in a portable handheld work apparatus. The mixture-forming unit comprises a fuel store (30), a switchable valve (40) and a fuel channel (20) which opens into an intake region of the engine (10). The valve (40) has an inflow port (41) which is connected to the fuel store (30) and an outflow port (42) which is connected to the fuel channel (20). A fuel column is mechanically moved by the switching of the valve. In order to compensate for this fuel column, the outflow port (42) is connected via a bypass channel (45) to the inflow port (41) and a flow valve (46) is mounted in the bypass channel (45). The flow valve (46) opens in flow direction (49) from the outflow port (42) to the inflow port (41) and blocks in the direction opposite thereto.

A carburetor may include a body having a main bore from which a fuel and air mixture is discharged for use by an engine, a throttle valve head, a choke valve head and a flow directing feature. The throttle valve head may be carried by the body and is moveable between an idle position and a wide open position to control at least some fluid flow through the main bore. The choke valve head may also be carried by the body and is moveable between a first position and a second position to at least in part control fluid flow through the main bore. And the flow directing feature associated with the choke valve head or the throttle valve head may alter at least one of the velocity or direction of at least a portion of the fluid that flows in the main bore.

A carburetor may include a body having a main bore from which a fuel and air mixture is discharged for use by an engine, a throttle valve head, a choke valve head and a flow directing feature. The throttle valve head may be carried by the body and is moveable between an idle position and a wide open position to control at least some fluid flow through the main bore. The choke valve head may also be carried by the body and is moveable between a first position and a second position to at least in part control fluid flow through the main bore. And the flow directing feature associated with the choke valve head or the throttle valve head may alter at least one of the velocity or direction of at least a portion of the fluid that flows in the main bore.

A simple engine, comprises (1) a cylinder, and a spark plug in the cylinder; (2) a carburetor, fluidly connected to the cylinder; (3) a primary air intake path, fluidly connecting atmosphere to the carburetor; (4) a carburetor bypass air intake path, fluidly connecting air to the cylinder without passing through the carburetor; and (5) a valve, along the carburetor bypass air intake path, for controlling the flow of air through the carburetor bypass air intake path.

A simple engine, comprises (1) a cylinder, and a spark plug in the cylinder; (2) a carburetor, fluidly connected to the cylinder; (3) a primary air intake path, fluidly connecting atmosphere to the carburetor; (4) a carburetor bypass air intake path, fluidly connecting air to the cylinder without passing through the carburetor; and (5) a valve, along the carburetor bypass air intake path, for controlling the flow of air through the carburetor bypass air intake path.