Charge air cooling

One of the chief measures used to reduce fuel consumption and thus CO2 emissions is to reduce the swept volume, typically in combination with turbocharging, in order to maintain or improve power output and torque. As the degree of turbocharging increases, the necessity of cooling the compressed air grows simultaneously. Charge air cooling therefore takes on an ever more critical role. The latest stage of development at MAHLE includes indirect cascaded charge air cooling, integrated in the intake pipe, which provides minimal pressure loss and significant packaging advantages. It produces charge air temperatures close to that of the coolant by using a two-stage cooling process.

Charge air coolers
There are two forms of charge air cooling: direct cooling with the ambient air, or indirect cooling via the coolant to the ambient air. Indirect charge air cooling offers benefits in terms of package size and dynamic response and will play an increasingly important role in the future. This involves placing the charge air cooler very close to the engine rather than in the front end of the vehicle. The additional low-temperature radiator needed for indirect charge air cooling is an integral part of the cooling module. Due to the smaller installation depth of the low-temperature radiator compared to a conventional charge air cooler, more space is available in the front end, which can then be used for various measures such as pedestrian protection. The location close to the engine permits the use of shorter charge air lines, cutting the pressure loss by around 50%. The higher density of the cooled charge air and lower pressure loss means there is more air available to the engine for combustion. The result: improved engine responsiveness.

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