In many of today’s diesel and gas engines, you’ll find two ‘chargers’ that are designed to increase engine efficiency. One runs hot, the other cold, and both use removable insulation blankets. The two ‘chargers’ that we are referring to are turbochargers and charge air coolers.


The purpose of a turbocharger (commonly referred to as turbo) is to increase the mass of air entering the engine to create more power. Turbochargers make this possible by using an engine’s exhaust gas flow to power a turbine with drives a compressor, which in turn increases the air flow into the engine’s cylinders. The more air present in the engine’s cylinders, the greater the air / fuel mix, and the the greater the resulting horsepower.

Since they use the engine’s own exhaust gas to drive the turbine located inside the turbo’s housing, turbochargers run hot. Combine this with the fact that the internal turbine can spin at speeds in excess of 200,000 rpm, and you have the potential for even more heat. And heat is what you want, as the greater the heat and resultant pressure of the exhaust, the faster the turbine will spin, and the more air gets pushed to the engine’s cylinders by the compressor.

This heat does have ramifications, however,  for safety and engine performance. An exposed hot turbocharger can pose a danger to personnel, as well as adversely affecting heat sensitive components that are nearby. As well, increased heat can increase stress on the piston, piston rings, cylinder liner, and cylinder head of the engine.

While the air that leaves the compressor section of the turbo is not as hot as the exhaust, (as the compressor is drawing in ambient air and not exhaust air), the act of compression does causes the temperature of the air to increase (for a typical diesel engine, to around the 200°C / 400°F mark). Since hot air is not as dense as cooler air, less air can be pushed into the engine cylinders, which in turns limits the effectiveness of the turbocharger. This is where Charge Air Coolers come into play.

Charge Air Coolers:

The job of the ‘Charge Air Cooler’ also known as an ‘intercooler’ or ‘aftercooler’ is to take the compressed  air and cool it down before it enters the engine. The resultant cooler air is more dense, and thus more air can be packed into the engine cylinders than could have been achieved with the hot air coming out of the turbo compressor.

Removable Insulation Blankets ‐ How They Help:

Firwin Turbocharger Cover

Firwin Turbocharger Cover

For turbochargers, a properly designed removable insulation blanket fitted on top of the turbo ‘hot side’, helps to keep the hot side of the turbo hot, and the cool side cool. This allows the turbo to function more efficiently. Nearby components that might be affected by the extremely hot ambient temperatures generated by an exposed turbocharger are also protected. Finally, there is the aspect of personnel safety – a turbocharger with a removable insulation blanket will protect people from accidentally burning themselves on an otherwise hot engine component.

CAT C27 / C32 Charge Air System with insulation blankets. Note the large cooler system (large black fan) in the background.

CAT C27 / C32 Charge Air System with insulation blankets. Note the large cooler system (large black fan) in the background.

For charge air coolers, removable insulation blankets are primarily found on the piping that leads from the turbo/compressor into the cooler/radiator. The cooler might be a bit of a distance from the turbo, and the piping, which can be in excess of 400°F for diesel applications (gas would be higher) can pose a hazard to personnel if not properly insulated. Covering these pipes with removable insulation blankets brings the outside touch temperature down to safe levels.

For more information on how Firwin can help you with your engine insulation needs, please visit our website , or call us at 1 877 347 9467.

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