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Exhaust Gas Recirculation (EGR) is an effective technique for reducing NOx emissions in order to achieve the ever more stringent emissions standards. This system is widely used in commercial vehicle engines in which thermal loads and durability are a critical issue. In addition, the development deadlines of the new engine generations are being considerably reduced, especially for validation test phase in which customers usually require robust parts for engine validation in the first stages of the project. Some of the most critical issues in this initial phases of program development are heavy boiling and thermal fatigue. Consequently it has been necessary to develop a procedure for designing EGR coolers that are sufficiently robust against heavy boiling and thermal fatigue in a short period of time, even when the engine calibration is not finished and the working conditions of the EGR system are not completely defined.

Exhaust Gas Recirculation (EGR) has been in use for many years to control NOx emissions in commercial vehicle applications. Emissions limits are tighter with every new regulation while durability requirements continue to increase, so EGR system manufacturers must be able to provide high performance and robust designs even with high thermal loads. The commercial vehicle market is characterized by lower production rates than passenger car programs and the same engine must cope with multiple applications that have totally different engine calibrations. In some cases it is necessary to design two or more EGR systems for an engine platform, with a consequential impact on cost and development timeline. The optimal design of an EGR system needs to take into consideration several topics related with performance and durability: efficiency and pressure drop, fouling, boiling, thermal fatigue, vibration, pressure fatigue and corrosion among others.