초록 ▼

An intake device for an internal combustion engine is provided with an intake passage-length change mechanism for changing the effective length of the intake passage for each cylinder, and a valve timing change mechanism for changing the closure timing of the intake valve for each cylinder. The inta

An intake device for an internal combustion engine is provided with an intake passage-length change mechanism for changing the effective length of the intake passage for each cylinder, and a valve timing change mechanism for changing the closure timing of the intake valve for each cylinder. The intake passage-length change mechanism is actuated, in a particular engine speed range, to change the effective length of the intake passage according to the engine speed so that the natural frequency of the intake system is tuned with the frequency of the pressure change in the intake passage which is determined by the engine speed, thereby enhancing the intake inertia effect to improve the engine output power. In the particular engine speed range, the valve timing change mechanism is actuated to make better use of the inertia effect enhanced by the intake passage-length change mechanism. Outside the particular engine speed range, the valve timing change mechanism is actuated to change the intake valve closure timing so that the volumetric efficiency is improved according to the engine speed.

대표청구항 ▼

An intake device for an internal combustion engine having an intake passage-length change means which is actuated to shorten the effective length of each intake passage as the engine speed increases so that the engine speed and the frequency of the air-column vibration in the intake passage are tune

An intake device for an internal combustion engine having an intake passage-length change means which is actuated to shorten the effective length of each intake passage as the engine speed increases so that the engine speed and the frequency of the air-column vibration in the intake passage are tuned with each other to obtain intake inertia effect, wherein the improvement comprises valve timing change means for changing at least the closure timing of each intake valve and control means for controlling the intake passage-length change means and the valve timing change means in response to each other according to the operating condition of the engine.