Two-stroke engine, and handheld power tool
AssigneeHusqvarna AB
InventorsMarkus Hedberg, Niklas Enander, Tobias Stalfors
Life of this patent
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Abstract
A two-stroke engine (1) is disclosed comprising a cylinder (2), a piston (3) arranged to reciprocate in the cylinder (2), a crankcase (5), a fuel injector (7) configured to inject fuel into the crankcase (5), an air inlet (9) connected to the crankcase (5), and a stratified scavenging intake (11) connected to the cylinder (2). The engine (1) comprises a throttle (13) configured to control the amount of air supplied to the air inlet (9) and to the stratified scavenging intake (11). The present disclosure further relates to handheld power tool (50) comprising an engine (1).
Claims11
A two-stroke engine comprising:
- a cylinder,
- a piston arranged to reciprocate in the cylinder,
- a crankcase,
- a fuel injector configured to inject fuel into the crankcase,
- an air inlet connected to the crankcase, and
- a stratified scavenging intake connected to the cylinder,
- wherein the engine comprises a throttle configured to control the amount of air supplied to the air inlet and to the stratified scavenging intake, and wherein the throttle is arranged such that more air is directed to the air inlet than to the stratified scavenging intake when the throttle is in a half open position,
- wherein the engine comprises a manifold arranged between the throttle and the air inlet and the stratified scavenging intake,
- wherein the engine comprises a separation wall between the air inlet and the stratified scavenging intake,
- wherein the throttle does not contact the separation wall in any position,
- wherein a length of the separation wall, measured in an intended air flow direction through the manifold, is within a range of 4-60%, of a length of the manifold measured in the intended air flow direction through the manifold in order to provide a balanced amount of spit back to occur through the manifold for efficient operation of the engine at all rotational speeds of the engine.
Dependencies are inferred from the claim text.