The purpose of an EGR or Exhaust Gas Recirculation cooler is to diminish Nitric Oxide emissions through a process which basically quenches the temperature of combustion. An EGR cooler will introduce a small amount of oxygen-poor gas into the stream of the air intake. This lower content of oxygen means that there will be less burn, producing a lower burn temperature, and therefore producing only a small amount of NOx. One thing to note is that it is of the utmost importance to control the Inlet Air Charge Temperature (IACT) on turbo diesels, as they are directly linked to exhaust gas temperature, or EGT. If this EGT level becomes too high, there are many expensive parts on the vehicle which can easily become damaged. In order to maintain the EGR cooler at optimal levels without allowing the IACT to spike, the EGR (Exhaust Gas Recirculation) Cooler's gas will be shot through a cooler that diminishes heat out, transferring it to the coolant system in order to maintain system balance.
Why you need an EGR Cooler
Just like the carbon dioxide our bodies expel is used as fuel for plant life, even a vehicles exhaust can be put to good use by providing an increase in fuel efficiency, allowing the vehicle to function with fewer emissions. A car's exhaust can be utilized as a heat source, warming an engine's coolant in order to allow the engine to continue running warm, whether or not the motor has been shut down for a lengthy period of time. Even the interior of the car can be warmed with exhaust heat, even when the weather is at its coldest! Exhaust Heat Recovery is a part of each of these individual technological breakthroughs, and an important part of it is the way in which it reduces the pollution produced by most internal combustion engines. The key to the recirculating of this exhaust heat is the EGR Valve. It will open when it is confronted with a vehicle exhaust system's backpressure, guiding it back into the combustion chamber, providing warmer fuel. At the point that the EGR valve can sense the engine being in possession of sufficient warmth, it will begin redirecting the exhaust in order to prevent overheating in the engine. These lower temperatures can also help augment a vehicle's fuel economy, minimize energy loss, and provide more power to its wheels.