1 MAP sensor
2 Intake manifold flap housing
3 Intercooler bypass
4 MAF sensor with integral IAT sensor
5 Connecting piece between turbocharger and intercooler
6 Intercooler
7 Turbocharger vacuum unit
8 Intercooler bypass flap servo motor
9 Intercooler/intake manifold flap connection
10 Intake manifold flap servo motor
An intake manifold flap housing has been added to the intake system in conjunction with the particulate filter system. The intake manifold flap housing contains the following components:
โข Intercooler bypass flap with servo motor,
โข Intake manifold flap with servo motor,
โข MAP sensor,
โข IAT sensor (not illustrated).
The intake manifold flap creates the connection between the cooled air from the intercooler and the intake ports of the engine via the intake manifold flap housing.
The intercooler bypass valve creates a direct connection between the compressor side of the turbocharger and the intake ports of the engine via the intake manifold flap housing. The intercooler is bypassed.
The intercooler bypass flap is adjusted via a servo motor during the regeneration phase of the diesel particulate filter.
During the regeneration phase the air mass flowing through the intercooler (regulated by the intake manifold flap) is reduced. At the same time, the flow of uncooled air mass via the intercooler bypass (regulated by the intercooler bypass flap) is increased. This reduces the engine’s cylinder charge while keeping the intake air temperatures constant to prevent variations in exhaust gas temperatures during regeneration. The position of both valves is dependent on the intake air temperature. For this reason, there is an additional IAT sensor in the intake manifold flap housing, downstream of the intake manifold flap and intercooler bypass flap (not illustrated).