Charge-air coolers: some design guidelines

Different factors must be considered in applying charge-air coolers to commercial or passenger vehicles. Future units will be constructed increasingly from fluxless brazed aluminum matrices and plastic headers. One of the most important tasks of internal combustion engine development is that of reducing mass per unit power while also reducing both fuel consumption and undesirable emissions. Efficient charge-air cooling is needed to counteract higher mechanical loads, higher thermal loads, and NOx emissions. Aluminum is particularly suitable since it can be brazed using a special brazing technique. For dimensioning and rig-testing purposes, it is important to consider that working pressures inside the charge-air cooler alter according to engine speed and load cycle. Charge-air/air coolers are normally screwed onto the radiator and mounted on the vehicle's frame or on the bodywork. The joint between the charge-air cooler and the engine and turbocharger must be sufficiently elastic to ensure that the charge-air cooler is not subjected to any excessively high forces.