Browse Publications Technical Papers 2006-32-0036
2006-11-13

Design and Development of a Gasketless Cylinder Head / Block Interface for an Open Deck, Multi Cylinder, Highly Turbocharged Small Engine 2006-32-0036

This paper describes the design and development of a gasketless interface, which was used successfully to couple an aluminium cylinder head to an open deck design cylinder block. The cylinder block was manufactured from aluminium, featuring shrink fit dry cast iron liners. Extensive CAE modelling was employed to implement the gasketless interface and thus avoid using a conventional metal or fiber based cylinder head gasket.
The engine was specifically designed and configured for the purpose, being a 430 cm3, highly turbocharged (TC) twin cylinder in-line arrangement with double overhead camshafts and four valves per cylinder. Most of the engine components were specially cast or machined from billets.
The new design removed the conventional head gasket and relied on the correct amount of face pressure generated by interference between the cylinder head and block to seal the interface. This had advantages in improving the structural integrity of the weak open deck design. Extensive FEM analysis determined the correct amount of interference needed for successful operation under all operating conditions.
Extensive thermal analysis concluded that removing the conventional gasket had the advantage of improving the heat path between the cylinder head and block, as the gasket behaves as an insulator. The possibility of gasket failure due to abnormal combustion is also eliminated.
The design proved successful in operation, withstanding knock amplitudes of 30 bar, in-cylinder pressures exceeding 100 bar and high combustion temperatures. The engine completed extensive static and transient testing with no interface problems after initial development, recording 25 bar brake mean effective pressure (BMEP) on pump gasoline.

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