As ever more stringent emission standards though out the world are forcing diesel engine makers to identify better ways to further reduce harmful nitrogen oxides and accompanying particulates from the engine's exhaust, Borg Warner has come up with an innovative solution, which enables the low-pressure recirculation of exhaust gas into the combustion chamber. In the past, various attempts to solve this problem were unsuccessful due to the extremely corrosive effect of the particulate-containing exhaust gas/air mixture that would rapidly destroy various components of the turbocharger compressor and other pieces of the intake route. Borg Warner's breakthrough innovation is a unique coating that protects the various components of the compressor against this assault, while simultaneously developing new mixer geometries that allow sufficient mixing of the fresh gas with the recirculated exhaust gas over short spaces and with low-pressure losses. Together these innovations have made low-pressure exhaust gas recirculation a "must have" technology on smaller diesel engine programs going forward if they are to meet the emission standards of tomorrow.
With the introduction of this innovation that improves diesel turbochargers in terms of suitability for low-pressure exhaust gas recirculation, engine manufacturers are able to sharply increase exhaust gas recirculation rates and therefore expand to operating ranges in which it was not possible before. Because exhaust gas is not extracted before the turbine but after it, this exhaust gas is available in the turbocharger in a more useful and efficiency-boosting manner, making it possible to achieve much better engine responses, not only in terms of nitrogen oxide emissions, but also lower fuel consumption.
This innovation first appeared on the Volkswagen Jetta that was introduced to the USA in 2009 and more recently, has been launched in the high volume Renault-Nissan R9M 1.6 liter programs for the Scenic and Grand Scenic vehicles.