Intake Manifold: Description and Operation
GF09.20-P-6010V Intake Manifold Component Description
Location
The intake manifold is located between the cylinder banks.
Task
Optimizes engine torque curve by means of two different intake manifold lengths Improves flow via swing-out tumble flaps in the intake port.
Design
The intake manifold is assembled out of several magnesium pressure castings. During assembly, the individual intake manifolds for each cylinder and the air manifold collecting sections are in the center. The intake manifold cannot be disassembled. A total of four shafts are stored in the intake manifold.
The vacuum pressure for the aneroid capsules is supplied by a vacuum reservoir in the intake manifold when the switchover valves are actuated. The reservoir volume is designed for several operations without renewed evacuation.
Intake manifold switchover, function
The individual intake manifolds each approx. 800 mm long, are arranged in a spiral shape around the air collecting volume. Each single intake manifold has a further opening to the air collecting volume somewhere in the middle. These can be opened or closed by rotating longitudinal switch flap shafts. The switch flaps of a cylinder bank are interconnected by a shaft and each of the flap is actuated by an aneroid capsule in case of engine 272 BOTH aneroid capsules for the intake manifold switchover are connected to the variable intake manifold switchover valve via hose pipes. Engine 273 has only one aneroid capsule. The flap shafts are connected in the intake manifold. The switch flaps open by spring force without actuation and enable the short suction way
At higher speeds (from approx. 3500/min) the intake manifold switchover aneroid capsules are ventilated and the switch flaps opened by the spring force. The intake air takes the short intake route.
At lower speed (up to approx. 3500/min) the intake manifold aneroid capsules are pressurized with vacuum pressure and the longitudinal switch flaps closed. The intake air takes the long intake route. The result is improved cylinder charge and thus an increase in torque.
Tumble flap switchover function
At partial load, tumble flaps can be fully swung out in each cylinder intake port in the intake manifold. This closes the intake manifold by around 50 %.
The flow speed of the intake air is increased and allows for improved distribution of the fuel/air mixture in the combustion chamber. The tumble flaps are actuated via an aneroid capsule and linkage.