Automobile Engineering in ME
The function of a first compression ring (top ring) is that it

Creates swirl
Maintains a seal and prevents escape of burned gases and loss of pressure in the combustion chamber
Increases the combustion temperature
Maintains a seal and prevents the fuel leakage

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Automobile Engineering in ME
In a ventilated disc brake

Disc contains many small holes for optimum cooling performance
A duct directs air towards the caliper for cooling while the vehicle is moving
Caliper is covered with cooling fins
Disc contains radial vanes between its rubbing surfaces for optimum cooling performance

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