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Practical Experience with Passenger Car Engine Blocks Produced in High Quality Compacted Graphite Iron
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Abstract
Although the superior properties of compacted graphite iron (CGI) are well known, its application to the series production of complex castings such as passenger car engine blocks has been precluded by the absence of a reliable foundry production technique. Despite the narrow chemistry range over which high quality CGI is stable, recent advances in cast iron foundry process control technology now serve as the starting point for a comprehensive CGI engine development programme at Adam Opel AG.
The Opel CGI programme originated with the 2.5 litre V-6 DTM racing engine which now delivers 2.7
times more power and weighs 20% less than the
standard grey iron production. Acoustical evaluations
where then performed on identically designed 2.0 litre
Family II engines to show that the audible noise level of
the CGI engine was 1.1 to 1.5 dB(A) less than that of
the grey iron engine. Simultaneously the 35% higher
elastic modulus of CGI relative to conventional grey
iron resulted in a 7% increase of the torsional vibration
frequency. Other benefits realised from the CGI studies
include a 70% reduction in bore distortion, 44%
improvement in honed surface roughness (Ra) and
more than 40% improvement in cylinder bore wear
resistance. As a result of these positive results Opel
has recently undertaken a complete redesign of its 1.4/1.6 litre Family I gasoline engine block for series
production. The new CGI block is 29.4% lighter than its
grey iron predecessor while providing the same power
output (105 hp). The purpose of this paper is to present
the results of the compacted graphite iron engine
development programmes at Adam Opel AG.
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Citation
Tholl, M., Magata, A., and Dawson, S., "Practical Experience with Passenger Car Engine Blocks Produced in High Quality Compacted Graphite Iron," SAE Technical Paper 960297, 1996, https://doi.org/10.4271/960297.Also In
References
- Dawson S. The SinterCast Process and Compacted Graphite Iron BCIRA International Conference on the Latest and Best in Melting and Metal Treatment in Ferrous and Non-Ferrous Foundries April 19-21 1994 28.1 28.6
- Fecker I. St. Gallen, Switzerland February 1989
- Indra F. Director of Advanced Development: Adam Opel AG Compacted Graphite Iron (CGI) - A new material for internal combustion engines Fahrzeug - und Motorentechnik '95 7-9 October 1995 Aachen, Germany
- European Patent EP 0 486 463 A2 11 November 1991