BMW 3: Belt drive
Comparison belt drive B46 engine and B46TU/B48TU engines
- B46 Engine (transverse installation shown)
- B46TU/B48TU engines (transverse installation shown)
- Deflecting element
- Alternator
- Coolant pump
- Air conditioning compressor
- Ribbed belt
- Torsional vibration damper
- Belt tensioner
The belt layout is a single-belt drive where all ancillary components are driven by one belt.
Changing the belt guiding has help to save both material and space.
The length of the drive belt changes due to thermal expansion and ageing. So the drive belt can transmit the required torque, it must be continuously in contact with the belt pulley at a defined pressure. To allow this to happen, the belt tension is exerted by an automatic tensioning pulley mounted on the alternator; the pulley compensates for belt elongation over the full service life.
In case of incorrect assembly of the drive belt, the coolant flow through the coolant pump is either insufficient or non-existent; there is thus a lack of cooling. There is a risk of damage to engine components and engine damage
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Split cooling
Split cooling is a new development for the B46TU engine. This cooling concept
is a modified version
of which is already used in the N63TU2.
The Split Cooling function uses the electrical Split Cooli
Heat management module
The heat management module replaces the characteristic map thermostat.
Heat management module
Electrical Split Cooling Valve (SCV)
Coolant output towards the coolant pump
Electrical actuator
Rot
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Functions
The cooling system has 2 operating conditions, which result from its
function:
Cooling OFF
Cooling ON
Cooling OFF operating condition
The "Cooling OFF" operating condition is active when the cell temperature is
in or below an optimal
range. This is generally the case if the vehicle is moved at
Antifreeze and corrosion inhibitor
The cooling system of the G20 PHEV is filled with the new antifreeze and
corrosion inhibitor Frostox
HT-12. The new antifreeze and corrosion inhibitor increases the long-term
stability and corrosion
protection of the components. It replaces the well-known antifreeze and
corrosion inhibitor Glysan
