Intake and exhaust systems

Design and function

Starting heater

The pre-heating and post-heating times are a factor of engine temperature.

The purpose of the starting heater is to warm up the air in the intake manifold when the engine is started. The heated air makes for easier starting and also reduces the generation of exhaust smoke during cold starts.

TAD-engines

Turbocharger

The turbocharger is powered by the exhaust gases which pass through the turbine housing to reach the exhaust system. The passage of the exhaust gases causes the turbine wheel to spin. On the same shaft as the turbine wheel is a compressor wheel. The compressor wheel spins in a compressor housing which is connected between the air cleaner and the engine's inlet manifold.

As the compressor wheel rotates, air is sucked in from the air cleaner. The air is compressed by the compressor wheel and is forced into the cylinders of the engine.

TWD-engines

Charge air cooler (Intercooler)

The TAD-engines is equipped with an air to air charge air cooler, the purpose of which is to lower the temperature of the intake air before it is blown into the engine cylinders.

The TWD-engines is equipped with a charge air cooler of the water to air type.

The charge air cooler lowers the air temperature by about 100°C/212°F (TWD) and 150°C/302°F (TAD) resp. and increases engine output. Engine torque is also higher and fuel consumption is lower.

On the TAD-engines the charge air is cooled when it is passing the charge air cooler which is placed behind the engine's cooler. The air is pressed from the turbocharger through the charge air cooler and into the inlet manifold (air to air cooling).

On the TWD-engines the charge air is cooled by the water cooled charge air cooler placed on top of the inlet manifold (water to air cooling).