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SkyPup
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Considered opinion in the automotive industry is that peak cylinder pressures will rise considerably in passenger cars, following the trend in heavy duty trucks, to improve the fundamental operating efficiencies. VW-AUDI Passenger car TDI cylinder pressures of 180 bar or even higher are being planned to meet EURO IV Emissions in 2005 and the even more stringent requirements of EURO V in 2007. The use of VNT turbocompressors with PR outputs over 3.0 and copper-brass intercoolers to return the heated pressurized air back to near ambient temperatures will achieve these goals.
Increasing cylinder pressures by as much as 40 bar or more for VW-AUDI diesel passenger car engines to meet 2005 emissions requires an enormous development in TDI technology.
As regards the engine structure, mechanical and thermal stresses will increase considerably. The engine designer is constrained by package size and fundamental dimensions which cannot be changed, whether for vehicle packaging requirements or manufacturing transfer line requirements in which dimensions such as bore centres cannot be altered for economic production.
Material improvements will be required to improve stiffness and mechanical and thermal fatigue behaviour.
The histogram shows the result of investigations carried out by AVL of Austria, and indicates the maximum safe operating cylinder pressures for the available crankcase materials with normally dimensioned engine designs. Note that V designs have lower maximum cylinder pressure potential than in-line designs because of the reduced number of main bearings and more complex stress loading of the main bearing walls.
It can be clearly seen that only CGI successfully allows the economic and practical realisation of the very high cylinder pressures planned for future TDI engines.
Practical fatigue investigations on production Diesel engines have shown an effective fatigue strength approaching double that of a geometrically equal grey iron block. This enormous advantage allows CGI designs of the future to be simultaneously weight reduced compared to today's designs, whilst still comfortably meeting the massive cylinder pressure rise.
CGI will become the basic engine construction
material of the coming generation of competitive Diesel engines.
Increasing cylinder pressures by as much as 40 bar or more for VW-AUDI diesel passenger car engines to meet 2005 emissions requires an enormous development in TDI technology.
As regards the engine structure, mechanical and thermal stresses will increase considerably. The engine designer is constrained by package size and fundamental dimensions which cannot be changed, whether for vehicle packaging requirements or manufacturing transfer line requirements in which dimensions such as bore centres cannot be altered for economic production.
Material improvements will be required to improve stiffness and mechanical and thermal fatigue behaviour.
The histogram shows the result of investigations carried out by AVL of Austria, and indicates the maximum safe operating cylinder pressures for the available crankcase materials with normally dimensioned engine designs. Note that V designs have lower maximum cylinder pressure potential than in-line designs because of the reduced number of main bearings and more complex stress loading of the main bearing walls.
It can be clearly seen that only CGI successfully allows the economic and practical realisation of the very high cylinder pressures planned for future TDI engines.
Practical fatigue investigations on production Diesel engines have shown an effective fatigue strength approaching double that of a geometrically equal grey iron block. This enormous advantage allows CGI designs of the future to be simultaneously weight reduced compared to today's designs, whilst still comfortably meeting the massive cylinder pressure rise.
CGI will become the basic engine construction
material of the coming generation of competitive Diesel engines.
