FOUR-STROKE ENGINE

Abstract

The invention relates to a four-stroke engine (100) comprising: at least one cylinder (11) comprising a combustion chamber (13); an intake manifold (21) connected to the combustion chamber (13); at least one intake valve (31) that opens and closes the intake orifice (17) which is the part connecting the combustion chamber (13) and the intake manifold (21); a throttle valve (33) fitted inside the intake manifold (21) and regulating the amount of air drawn into the combustion chamber (13); a throttle position detector (42) that detects the position of the throttle valve (33); a fuel injection mechanism (50) which injects fuel into the intake manifold (21);and the control mechanism (60) controls the fuel injection mechanism (50) based on at least the signal of the throttle position sensor (42), in which the control mechanism (60) collects the amount of fuel injected when the intake valve (31) is closed and the amount of fuel injected when the intake valve (31) is open such that the amount of fuel injected when the intake valve (31) is closed corresponds to the first throttle position change rate (RI) at the throttle position change rate (33) before the start of fuel injection (Jl) when the intake valve (31) is closed, and the amount of fuel injected when the intake valve (31) is open corresponds to the second throttle position change rate (R2) at the throttle position change rate (33) after the start of fuel injection (Jl) when the intake valve (31) is closed.;