Exhaust gas recirculation coolers are an important part of the emission control system on gas and diesel fueled engines. They are sometimes referred to as a heat exchanger. The primary job that the Exhaust Gas Recirculation (ERG) perform is to cool the exhaust prior to the gas’s recirculation. After combustion occurs in the cylinders, the remaining gas would normally exit the engine through the exhaust system, but on engines that employ ERG, the a percentage of the exhaust gas is fed back to the engine cylinders.
After combustion occurs in the cylinders, the remaining gas is primarily made up of Nitrogen oxide, which is referred to as NOx. Exhaust Gas Recirculation (ERG) is designed to feed a portion of the cylinders exhaust back into the combustion chamber. The ERG cool helps to reduce the volume of exhaust that is created by combustion engines. Nitrogen Oxide is created at high temperatures, so cooling the mixture before it is fed to the cylinders helps to reduce emission levels produced by the engine. Depending on the type of engine, 5-15% of the exhaust is returned to cylinders via the ERG system.
Without an ERG cooler, the exhaust gas would remain at a high temperature and combustion would cause an increase in Nitrogen Oxide. A faulty ERG valve has the potential to cause poor engine performance, increased fuel usage, and higher NOX emissions. Replacing the ERG valve and ensuring that the ERG cooler is working properly, will not only reduce NOx emissions it can also help the vehicle to remain in compliance with state emission standards.