Engine System

An engine system includes a single-cylinder engine (10) and an ECU. A crankshaft (13) is rotated in a reverse direction by a starter/generator (14) at the start-up of the engine. A valve driver (17) drives an intake valve (15) such that fuel injected by an injector is led to a combustion chamber (31a) from an intake passage (22) through an intake port at a first time point in a period during which the crankshaft (13) is rotated in the reverse direction. Thereafter, a fuel-air mixture is ignited by an ignition plug at a second time point at which the fuel-air mixture is compressed in the combustion chamber (31a) by the rotation of the crankshaft (13) in the reverse direction and a piston does not reach a compression top dead center.