To provide an engine intake system capable of improving exhaust gas properties at a cold driving range, stabilizing an idling speed at an idling running range after warm-up running is over, and avoiding worsening the exhaust gas properties.
In this engine intake system equipped with a fuel injection valve 20 spraying and feeding fuel into an intake passage 3e or a combustion chamber, and a throttle valve 15a being installed at the upstream side from the fuel injection valve 20 and variably controlling an amount of intake air flowing into the intake passage 3e, it is also equipped with a sub intake passage 16 which interconnects a more upstream side part than the throttle valve 15a and a more upstream side part than an intake valve opening 3c of the intake passage 3e, and making intake air flow into the upstream side from the intake valve opening 3c of the intake passage 3e, a sub intake control valve 17 variably controlling the amount of intake air flowing this sub intake passage 16, and a control valve controlling means 18 controlling the opening of the sub intake control valve 17 to the opening conformed to an engine driving state, respectively.
| JPS57102516 | INTAKE DEVICE FOR ENGINE |
IIDA YOSHIKATSU
SAITO TOSHIHIKO
