Intercooler

An intercooler ( Abbr: LLK, English intercooler ) is a heat exchanger that reduces the temperature of the engine combustion air supplied to the intake tract of a supercharged internal combustion engine. The charge air cooler is installed in the intake duct between the compressor ( compressor of a turbocharger or compressor ) and the inlet valve, leading from a portion of the heat generated by the compression of the air in the turbocharger.

The objective is to improve performance and increase engine efficiency. By reducing the temperature of the air supplied to a larger mass of air contained in the same volume, thereby proportionately more fuel to be burned. The charge air cooler thus increasing the potential power output.

Intercooler not only play with powerful engines and racing a role, but also for the downsizing of engines, since the charge-air cooling for smaller engines more power and lower fuel consumption possible. Especially with diesel engines intercoolers are practically indispensable, as not achieved with naturally aspirated and supercharged engines without cooling today's standard fuel economy and exhaust emission limits can not be met.

Operation

The intensive form of the general gas equation can be used for the approximate steady-state flow process of related

Derived.

This means that the mass of air required for the combustion can be increased in two ways:

• The density of the inducted air at the inlet valve of the engine is increased by the polytropic compression of the loader, however, simultaneously increases the temperature of the air, since the mechanical working of the compressor increases the internal energy of the compressed air and thus the temperature thereof.
• After compression, the increased air temperature is reduced in the charge air cooler heat dissipation to the environment and thus the mass flow rate () of the combustion air is further increased because the compressor can produce more air at the same boost pressure.

The increasing density of air in the combustion chamber causes the following:

• The most important effect is that more oxygen to the combustion chambers. Characterized and can be burned to increase the performance and efficiency of the engine more fuel.
• Because of the lower air temperature lower thermal load on the engine ( cylinder head and cylinder walls, valves, spark plugs (only petrol engine), bulb, but also of the turbocharger itself, which can rotate slower at the same flow rate ) and avoid combustion problems ( knock (only petrol engine), deterioration of exhaust emissions, uneven burning, etc.).

The disadvantages of the charge air cooler are:

• Costs by an additional component, higher expenses during the flow calculation of the engine compartment ( cooling air guide for charge air cooler) and in the arrangement (packaging ) of the components in the engine compartment.
• Larger volume of gas between compressor and inlet valve, thereby possibly worse engine response during load changes.
• Increased flow resistance for the intake air, over the service life increased by oil from the crankcase ventilation deposited and, if necessary, particles from the exhaust gas recirculation.

Designs

Intercooler themselves are either air-or water-cooled. In the latter case the heat to a separate cooling circuit is made. There are also other variants, so the cooling effect of an air-cooled intercooler can be increased by spraying with water, but out of the question because of the additional construction and maintenance costs in motors for racing use (eg in the WRC). However, since local vehicles must be derived and homologated for road vehicles, you will find this technique already in normal cars, such as the Subaru Impreza WRX STi.

Cultivar car / truck area

• FMIC ( FrontMountedInterCooler ), mostly centered in the front.
• SMIC ( SideMountedInterCooler ), laterally, sometimes two pieces, left and right.
• TMIC ( TopMountedInterCooler ), mounted above the engine ( the incident airflow is then usually about an air scoop )