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Based on the emission inventory Fig. 1, the Swiss 1998 Ordinance on Air Pollution Control (OAPC) mandates curtailment of carcinogenic diesel particle emissions at type B construction sites [1]. Moreover, particle traps are compulsory at underground workplaces [2]. In compliance, more than 6,000 Diesel engines were retrofitted with various particle trap systems. Many traps surpassed 99% filtration efficiency and secondary emissions were mostly prevented. However, trap failure due to mechanical and thermal damage was initially rather high at about 10%. By the year 2000 the failure rate was halved to about 6%. Thanks to focussed improvements, the year 2003 statistics show yearly failures of “only” about 2%. The Swiss target is to retrofit 15,000 construction machines with traps, fully compliant with environmental directives, having 5,000 operating hours durability and failure rates below 1%. Traps must pass the VERT suitability test before deployment.

The Oppenheim Correlation (OPC) is a new empirical algorithm, which allows a simple estimate of heat losses to the wall during the combustion in IC-engine. In present paper the results of different applications of OPC will be shown. Even if there are still several needs and ideas for further research it can be stated, that the OPC is a promising possibility of modeling the wall heat losses and due to its simplicity it has to be recommended to the engine community. The OPC can be used not only for didactics purposes, but also for quick simulation of wall heat losses and eventually for the on-line regulation of the cooling system.