The reduction of future diesel engine NOx emission limits forces the heavy and light duty diesel engine manufactures to develop system to comply more stringent legislation. Today the most effective method to do that is through the use of cold Exhaust Gas Recirculation (EGR) in order to reduce the peak temperature in the combustion chamber, and where the EGR cooler plays a very important role.
The reduction in allowable emissions within the new legislation, forces the increase of EGR rates, requiring EGR coolers with a higher thermal dissipation capacity. This increase in thermal efficiency needs also to be done without compromising other requirements in the design of the EGR cooler, such as the cooler size, the pressure drop in the gas circuit, the fouling behaviour and, of course, costs. Corrugated tube technology allows increase of thermal performance in EGR coolers without affecting these critical design requirements.
This paper illustrates the further progress in EGR coolers using corrugated tube technology. The study shows that the results of computational fluid dynamic simulations for different corrugated profiles and designs, the testing facilities used in the testing plan and the test results that Dayco ENSA has found. Comparison to smooth tube cooler concepts is also made. These results are analysed to determine and define the relationships between the design parameters of the corrugated tubes and smooth tubes, and their effect on thermal performance, pressure drop and fouling behaviour.