Intake manifold component description (engine 272) - GF09.20-P-6010V

Shown on ENGINE 272

Fig 1: Identifying Intake Manifold Components - Shown On Engine 272

Courtesy of MERCEDES-BENZ USA

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.

Shown on ENGINE 272

Fig 2: Identifying Intake Manifold Design - Shown On Engine 272

Courtesy of MERCEDES-BENZ USA

Shown on ENGINE 273

Fig 3: Identifying Intake Manifold Design - Shown On Engine 273

Courtesy of MERCEDES-BENZ USA

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.

Cut at intake manifold at cylinder level, short intake route

Fig 4: Identifying Longitudinal Switch Flap Open

Courtesy of MERCEDES-BENZ USA

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.

Cut at intake manifold at cylinder level, long intake route

Fig 5: Identifying Longitudinal Switch Flap Closed And Tumble Flap

Courtesy of MERCEDES-BENZ USA

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.