Charge Air Coolers

What is a charge air cooler?

The charge air cooler (or scavange air intercooler) is located between the turbo charger and the engine air inlet manifold. The purpose of the charge air cooler is to reduce the air inlet temperature thereby increasing air density thus giving an increase in engine efficiency. Typically the charge air cooler will cool air from 200 ºC to 45 ºC with high air velocities. It is obviously important to meet the required performance but with the high air velocities, it is imperative that the construction has high integral strength. Seawater is usually used as the cooling medium and so high quality materials are needed to ensure a long serviceable life. Leaking or damaged charge air coolers can cause loss of power, increased emissions, increased fuel consumption and increased exhaust temperatures leading to excessive engine wear/damage. The air cooler is therefore an integral part of any turbo charged diesel engine.

How are they built?

Historically, replacement air coolers purchased from replacement suppliers were produced using separate "spiral wound" finned tubes. One can still purchase these from many sources around the world. This process is however expensive and time consuming. More importantly, it is very difficult to predict the thermal properties of an air cooler manufactured in this way. Often, a charge air cooler manufactured using "sprial wound" tube produce a high pressure drop, thereby starving the engine of air at higher speeds.

AMI Exchangers addressed this issue many years ago when we developed the "block fin" method of construction - now an industry standard.

What is block fin?

What is block fin? "block fin" is a method whereby a single fin, encompassing several tubes, is assembled in one complete operation. This method is quick to manufacture, cost effective, extremely efficient and offers superior mechanical strength. Once tested, the thermal properties can be used to accurately predict the air cooler characteristics when in service. Because dimensions are fixed, each type of block fin will have individual heat transfer characteristics and this is why we at AMI have developed many fin types, each offering a different thermal performance. Our coolers are fitted with full intermediate support plates within the fin block to give additional stability against vibration.

What options are available?

What options are available? The original charge air cooler's thermal properties vary depending upon many factors such as original manufacturer, air quantity, temperatures, etc. It is therefore impossible to satisfy all requirements with only one type of fin - some of our competitors will try to convince you they can.

How many fin types do AMI have?

How many fin types do AMI have? We at AMI have built up the largest selection of "block fin" within our industry. We currently have SEVEN thermally different fin options available and we are continuing to develop more. Each of our fin types is specifically designed to provide a unique thermal performance in order to meet the individual needs of specific engines. No other supplier is better equipped to provide proven thermally engineered solutions to their clients

Are AMI Charge Air Coolers equivalent to OEM?

Due to the quantity of fin types available to us, we always have a fin option that will allow us to build an air cooler that has thermal specifications equal to or better than the original unit. Occasionally, clients are unhappy with the original air cooler performance and in these circumstances we can offer to build a new cooler with improved efficiency or reduced pressure drop. The dimensions of the air cooler can be obtained from our extensive database of drawings, surveys onboard or from samples sent to our workshops.

What about the new NOx regulations?

he NOx emissions of your engine are effected by the condition of the charge air cooler. In coming years, vessels will need to prove that the air cooler manufacturer has offered a cooler with the same performance as the original. Technical files are now being prepared on new vessels and regulations are in place to ensure charge air cooler thermal data exists within this file. Our fin types have been tested at independent test facilities and results used within our complex thermal design software. If we are supplied with the original thermal data, we can offer ACURATE thermal specifications of our cooler - thereby satisfying NOx Requirements!

What about quality?

We manufacture air coolers using high quality materials. We buy these materials in bulk direct from European manufacturing mills. This enables us to better control the quality of materials. All charge air coolers are available with material certificates. Our quality procedure includes full traceability of material and workmanship. The air cooler is checked at various stages of production ensuring quality throughout all areas of manufacture. Some examples of customer comments can be found on this site.

What quality assurances can you give?

We can arrange certification by most internationally recognised independent classification societies (Lloyds Register, ABS, DNV, NKK, G. Lloyds, etc).