| Variable Intake Manifold The air necessary for combustion in the engine flows through the intake manifold to the intake valve. Modern-day fuel injection systems for petrol engines inject the fuel into the intake manifold directly upstream of the intake valve. The length of the intake manifold is subject to variable – and actually contradictory – demands in different driving states in order to ensure the highest possible air inflow rate at all engine speeds and provide good cylinder charging. Whilst at low revs torque needs to be delivered as rapidly as possible – best attained by means of a short intake manifold – maximum power output at high revs demands long intake manifolds. The variable intake manifold features an electronically controlled flap system to meet both those demands, channelling the air via the short intake manifold at low revs and through the long section at high revs. |
