PIERBURG explores the function and application of cooled exhaust gas recirculation. Ever more stringent emission regulations require a constant improvement in pollutant reduction methods. For diesel engines this particularly applies to a further reduction in nitrogen oxides (NOx). Cooled exhaust gas recirculation (EGR) can play a significant role in this context. Thanks to such cooling, the combustion chamber temperatures are lower, as is the level of nitrogen oxide formation. Based on years of experience in the development and manufacture of EGR systems, PIERBURG has designed a whole range of EGR cooler modules to permit the precise cooling of exhaust gases. Many of today's EGR coolers feature an electrically or pneumatically switched bypass flap. The bypass flap allows the exhaust gases to be routed past the EGR cooler in the warm-up phase so that the engine and catalytic converter achieve their operating temperature more quickly. A further advantage is a reduction in noise generation, so-called 'diesel knock', as well as in the level of raw hydrocarbon emissions in the warm-up phase. Bypassing is also possible if high exhaust gas temperatures are required, for example for the regeneration of diesel particulate filters.
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