Cylinder Head - Audi V6 BITURBO Manual

Cylinder head

The cylinder heads are largely identical to
those used in the V6 naturally aspirated
engine. Common parts are used for both banks
of cylinders.
The mounting position of the right-hand
cylinder head is rotated through an angle of
180° in relation to the left-hand cylinder head.
The timing of the inlet camshafts is engine-
dependent.
To improve heat dissipation, the exhaust
valves are sodium-filled.
Tumble duct
In combination with five-valve-
per-cylinder technology, the inlet
duct is shaped as a so-called
"tumble duct".
Tumble effect
The shape of the inlet duct causes the drawn-
in air to tumble.
Advantages:
A good degree of swirl and high ignitability
•
fuel-air mixture are achieved
The tumble effect allows more efficient
•
combustion
For a turbocharged engine, the compression
ratio of 9.3 : 1 is high.
Advantage:
High "basic torque level" and fuel
•
economy
Tumble duct
SSP 198/78
7