What is an egr cooler?
An EGR (Exhaust Gas Recirculation) Cooler is a heat exchanger installed in the EGR circuit. The EGR system recirculates exhaust back to the engine in order to reduce NOX (Nitrous Oxide) emissions. The cooler simply cools the exhaust gas prior to gas being reintroduced into the engine. By cooling the gas the combustion temperature is reduced and NOX also as NOX is formed at higher temperatures.
Various cooler (heat exchanger) technologies are used by manufacturers, although tube and shell is the most common type used currently. Coolers will vary in size depending on the engine size and the emission standard the engine must comply with.
What is an oil cooler?
An oil cooler is a separate, smaller radiator from an engine’s main radiator, which maintains an oil supply at a consistent, optimal temperature.
Generally, the lubricating oil used in automobile engines works well between 82-93 degree centigrade. It becomes ineffective; At high temperature, the oil becomes thin this limits cross these values. hence it cannot create a proper lubrication film between the mating parts.
To reduce this effect, oil cooler is used which reduces the temperature of the oil so that it retains its ability to act as a film in between the moving parts.
The deteriorating oil gradually loses its cooling and lubricating ability. As such, there is a need of a device which takes away the oil from the hot parts of the engine and cools down before it is circulated back, from the oil pan.
There are two main designs known for engine oil cooler, tube-fin style and stacked plate style. In tube-fin style, the hot lubricating oil is made to circulate through the tubes where it loses heat with the help of fins. On the other hand, the stacked plate style forces the oil to flow through the stacks of number of plates where the heat from the oil extracted with the help of flowing air, above these stacks.
Oil cooler is also needed for a vehicle with automatic transmission as lots of heat, is generated inside the transmission when the gears are changed frequently. Although, it is not required while driving on a highway as gear shifts are minimal, an oil cooler used with the transmission ensures longer life of the gears as well as smoother gear shifts.