Variable intake manifold component description - GF09.20-P-6002SM

ENGINE 113.986

ENGINE 113.987

ENGINE 113.988

ENGINE 113.989

Fig 1: Identifying Variable Intake Manifold - Engine 113.988

Courtesy of MERCEDES-BENZ USA

The variable intake manifold is located centrally between the cylinder banks.

Task

The variable intake manifold optimizes the engine torque in the partial load range by modifying the intake routes (intake lengths).

Design

Fig 2: Identifying Variable Intake Manifold Design - Engine 113.988

Courtesy of MERCEDES-BENZ USA

Cross-section view from rear (at cylinder level)

Fig 3: Identifying Variable Intake Manifold Cross-Section View From Rear (At Cylinder Level) - Engine 113.988

Courtesy of MERCEDES-BENZ USA

Design

The variable intake manifold is assembled out of several pressure castings. When fitted together, they produce the individual intake manifolds and the air collecting volume. The parts are sealed off to each other by plastic.

The individual intake manifolds each approx. 800 mm long, are arranged in a spiral shape around the air collecting volume. A single intake manifold is assigned to each cylinder.

Each single intake manifold has a further opening to the air collecting volume in the middle. The opening can be opened or closed by the variable valve, which rotates by around 60°.

The variable intake manifold can not be disassembled.

Function

The variable valves (22/2) are attached to steel shafts. One steel shaft is installed for each bank of cylinders. The interconnected shafts are closed by vacuum pressure by the variable intake manifold vacuum capsule (22/6) by vacuum pressure.

(Y22/6) When the variable intake manifold switchover valve is open, the vacuum is supplied from a vacuum reservoir with check valve from the variable intake manifold. The reservoir volume is designed for about 5 operations without renewed evacuation.

The variable valves are opened from closed position by spring force.