Community Research and Development Information Service - CORDIS


The sources of hydrocarbon emissions from internal combustion engines have been studied for almost 40 years. Today it is generally accepted that two major mechanisms cause most of the hydrocarbon emissions of SI engines. The first effect is the absorption and desorption of fuel in the oil film. The second and most important effect is the quenching effect in crevices of the combustion chamber. The biggest crevice volume is located above the top compression ring between piston and cylinder liner. This volume contributes, as an estimation, to more than 50 % of the exhaust hydrocarbon emissions. An investigation of the interaction between flame propagation into the top land crevice and the exhaust hydrocarbon emissions was performed and the results for engine operation at low part load are presented in this paper. In order to detect flame propagations into the top land volume, the crevice was observed with the help of the opical fibre technique: 60 optical probes were applied to a production 4-cylinder, 4-stroke SI engine. The influence of crevice volume on hydrocarbon emissions was researched by varying the crevice geometry in the same engine, but maintaining a constant compression ratio.

Additional information

Bibliographic Reference: Paper presented: 4th International Conference on Vehicle and Traffic Systems Technology, Strasbourg (FR), June 16-18, 1993
Availability: Available from (1) as Paper EN 37294 ORA
Record Number: 199310698 / Last updated on: 1994-11-29
Original language: en
Available languages: en