| 摘要 |
Because a fuel temperature is low in a cold state, adhesion of fuel to a piston is increased and PMs are increased. By injecting fuel during a time period after an exhaust valve is closed but before an intake valve is opened, vaporization is promoted, and therefore, the adhesion of fuel to the piston can be reduced. However, in a case where a fuel injection time period is prolonged and only an exhaust valve is advanced, residual gas is increased. This causes deterioration in exhaust and fuel efficiency. In a cold condition of a cylinder direct injection engine, a time period from a timing at which an exhaust valve is closed to a timing at which an intake valve is opened is defined as a fuel injectable time period, and a fuel injection time period is set so that all or almost all fuel is injected during the fuel injectable time period, when an exhaust valve advance amount from a reference position is defined as ± [deg.], an intake valve delay amount from the reference position is defined as P [deg.], and a fuel injection time period increase amount is defined as ³ [deg.] on the basis of an exhaust valve closing timing, an intake valve opening timing, and the fuel injection time period in a condition in which the fuel injection time period is minimum, the intake and exhaust valves are controlled so that ± + ² is increased as ³ is increased, and ² > ± is satisfied in a condition in which ³ becomes maximum which is an upper limit of an application range. |
