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An intercooler, or Charge Air Cooler , is an air-to-air or air-to-liquid Heat Exchange Device used on Turbocharged and Supercharged Internal Combustion Engine s to improve their Volumetric Efficiency by increasing intake air charge density through Isochoric cooling. A decrease in air intake temperature provides a denser intake charge to the engine and allows more air and fuel to be combusted per engine cycle, increasing the output of the engine. The ''inter'' prefix in the device name originates from historic Compressor designs. In the past, aircraft engines were built with air charge coolers that were typically installed between multiple stages of supercharging, thus the designation of ''inter''. Modern Automobile designs are technically designated aftercoolers because of their placement at the end of supercharging chain. This term is now considered archaic in modern automobile terminology since almost all production vehicles have single-stage superchargers. Intercoolers can vary dramatically in size, shape, and design, depending on the performance and space requirements of the entire supercharger system. Common spatial designs are front mounted intercoolers (FMIC), top mounted intercoolers (TMIC), hybrid mount intercoolers (HMIC). Each type can be cooled with an air-to-air system, air-to-liquid system, or a combination of both. APPLICATIONS TO SUPERCHARGING Turbocharger s and Supercharger s are engineered to forcefully induct more gas in an engine's Intake Manifold . A larger intake charge provides more torque than a naturally-aspirated engine of identical characteristics. Intercooling is a method used to compensate for Heat ing caused by rapid gas compression, a natural byproduct of the semi- Adiabatic compression process. At very high output pressures, intake charges become excessively hot, significantly lowering the performance gains of supercharging due to decreased Density . Increased intake charge temperature can also increase the cylinder combustion temperature, causing excessive wear or heat damage to an Engine Block . Passing a compressed, and subsequently heated, intake charge through an intercooler lowers its temperature and increases its density. This increases performance by recovering some losses of the inefficiency of the compressing process by dumping excess heat to the atmosphere. Additional cooling can be provided by externally spraying fluid on the intercooler surface to further reduce intake charge temperature through Evaporative Cooling . Intercoolers that exchange their heat with the atmosphere are designed to be mounted in areas of an automobile with maximal air flow. These types are mainly mounted in front mounted systems (FMIC). Cars such as the Nissan Skyline , Saab , Dodge SRT-4 , Mitsubishi Lancer Evolution all use front mounted intercooler(s) mounted near the front bumper, in line with the car's radiator. Many older turbo-charged cars, such as the Toyota Supra , Mitsubishi 3000gt , Saab 900 , Volkswagen , Audi , and Turbo Mitsubishi Eclipse use side-mounted air-to-air intercoolers (SMIC), which are mounted in the front corner of the bumper or in front of one of the wheels. Side-mounted intercoolers are generally smaller, mainly due to space constraints, and sometimes two are used to gain the performance of a larger, single intercooler. Cars such as the Subaru Impreza WRX , MINI Cooper S , MAZDASPEED 6 and the PSA Peugeot - Citroen turbo diesels, use air-to-air top mounted intercoolers (TMIC) located on top of the engine. Air is directed through the intercooler through the use of a Hood Scoop . In the case of the PSA cars the air intake is the grille above the front bumper, then flows through under-bonnet ducting. Top mounted intercoolers sometimes suffer from heat diffusion due to proximity with the engine, warming them and reducing their overall efficiency. Some World Rally Championship cars use a reverse-induction system design whereby air is forced through ducts in the front bumper to a horizontally-mounted intercooler. Because FMIC systems require open bumper design for optimal performance, the entire system is vulnerable to debris. Some engineers choose other mount locations due to this reliability concern. FMIC can be located in front of or behind the radiator, depending on the heat dissipation needs of the engine. —the Top Mounted Intercooler is circled in red.]] AIR-TO-LIQUID INTERCOOLERS The use of a liquid system to cool intake charge is sometimes known as a charge cooler. Air-to-liquid intercoolers are Heat Exchanger s that eject intake charge heat to a intermediate fluid, usually water, which finally ejects heat to the air. These systems use radiators in other locations, usually due to space constraints, to eject unwanted heat, similar to an automotive radiator cooling system. Charge coolers are usually heavier than their air-to-air counterparts due to more components making up the system, due to the waterpump, radiator and fluid. Toyota Celica GT-Four had this system in the 1988-89 version and also in the Carlos Sainz RC Version. EXTERNAL LINKS
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