Component description for the variable intake manifold - GF09.20-P-6002AMG

ENGINE 156.980 in MODEL 164, 251

ENGINE 156.982 in MODEL 209

ENGINE 156.983 in MODEL 211, 219

ENGINE 156.984 in MODEL 216, 221

Location

The variable intake manifold is located in the middle between the cylinder heads.

Fig 1: Identifying Variable Intake Manifold

Courtesy of MERCEDES-BENZ USA

Task

Switching between long and short intake routes can occur with the variable intake manifold. The vibration response of the intake air for different operating conditions is used in a specific way to achieve internal charging.

External structure

The variable intake pipe lengths also allows better distribution of the mixture which leads to better combustion and thus to a higher engine torque.

Fig 2: Identifying Variable Intake Manifold Components

Courtesy of MERCEDES-BENZ USA

Internal structure

The variable intake manifold consists of a number of magnesium 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 variable intake manifold must not be disassembled down to the housing bottom section and the throttle valve actuator.

Fig 3: Identifying Throttle Valves, Variable Flaps And Air Guide Duct

Courtesy of MERCEDES-BENZ USA

Function Short intake routes (Switch flaps opened)

Short intake routes improve the engine torque at low rotational speeds and low loads. Short intake routes also achievement of high motor speeds.

Fig 4: Short Intake Routes Rotation Function

Courtesy of MERCEDES-BENZ USA

The variable intake manifold switchover valve is de-energized and the aneroid capsule is ventilated. The switch flaps are or will be opened through the spring force of the vacuum unit via the gearshift linkage and releases the short intake routes.

The switch flap shafts of the right and left cylinder head are connected at the rear in the variable intake manifold via a further gearshift linkage.

Long intake routes (Switch flaps closed)

Long intake routes improve the engine torque at low rotational speeds and high loads.

Fig 5: Long Intake Routes Rotation Function

Courtesy of MERCEDES-BENZ USA

The variable intake manifold switchover valve is actuated at the ground end from the ME-SFI [ME] control unit (N3/10) and switches off the vacuum from the vacuum reservoir through to the vacuum unit. The aneroid capsule actuates the gearshift linkage of the switch flap shafts and the switch flaps close the short intake routes.