what's new in: Engine fans

Heavy-duty truck cooling systems are going to have to work even harder when 2007 and 2010 emissions regulations go into effect. In anticipation, the makers of truck fans and fan drives have been engineering new products capable of cooling these hotter running engines and designing them for greater flexibility in positioning under the hood.

Last spring, BorgWarner introduced the Cool Logic fan clutch. Cool Logic was built specifically to work with 2007 EPA-compliant Class 8 engines. The proprietary fan clutch technology, the manufacturer explains, has increased torque capacity and a multi-speed operation, which electronically controls the fan speed for optimal engine cooling. It is also designed to reduce fan noise and to be completely maintenance-free.

When integrated with BorgWarner fan systems, the company explains, Cool Logic technology allows for the severe cooling needs of higher heat-rejection engines at various operating points. When severe cooling is not required, the system will provide optimized cooling with increased fuel economy savings from reduced fan horsepower usage.

BorgWarner also notes that starting January 1, the Kysor K26RA on/off fan drive replaced all K22RA production and service applications. The product upgrade, the company reports, offers superior torque capacity to meet higher engine cooling demands, while maintaining the reliability, ease of maintenance and higher customer satisfaction of its predecessor, the K22RA.

Last summer Horton also introduced a new product designed to meet the cooling needs of EGR (exhaust gas recirculation) engines in heavy-duty trucks. The WindMaster Plastic HS11 fan is an 11-blade fan that's available in diameters from 28 to 34 inches. According to the manufacturer, the computer-optimized blade design maximizes deflections and reduces fan stress, providing more stable airflow and quieter operation.

The WindMaster Plastic HS11 also has a honeycomb-patterned flat center section for improved stacking ability and reduced shipping and storage costs, Horton notes. The fan is compatible with both Horton fan drives, as well as those from other manufacturers.

Flex-a-lite Heavy Duty Division offers truck engine cooling fans designed to be direct replacement units for OEM fans on nearly all makes of trucks and buses. The company says its newest product is designed to replace the original fan clutch on full-sized Chevy and GMC pickups and Suburbans with 34-in wide radiators.

Flex-a-lite also produces belt-driven flex fans, which it says are suitable for applications where more cooling capacity is needed than a clutch fan can provide. The manufacturer also offers a number of electric fan options. The advantages of these, the company reports, are that they provide constant cooling, maintaining their rated airflow at all times.

Because electric fans are not engine-driven, there is very little horsepower loss compared to belt-driven fans, Flex-a-lite explains. Electric fans are also versatile. They can be mounted in front of or behind the radiator, and are available in various sizes and dual-fan arrangements. Electric fans can be used as the primary cooling source or as an auxiliary unit with a belt-driven flex or a clutch fan.

Electric fan drives are also available to the truck and bus market from Electric Fan Engineering (EFE). According to the company, these fan drives, which run off the battery rather than the engine, perform the same function as mechanical fan drives but are especially suitable for newer '07 emissions requirements, where remote mount radiators and other unconventional positioning of cooling equipment will mean the engine needs to be cooled electrically or hydraulically. EFE offers both.

The company points out its electric fans can be easily installed on engine radiators, air conditioning condensers or other types of heat exchangers as an alternate means of solving fan alignment problems, overheating and engine compartment overcrowding.

EFE recently introduced a 36-in.-diameter, 6-hp., 42-volt electric fan assembly. According to the company, it is suitable for most of today's truck applications. Because it runs off the truck's battery, it can help increase fuel economy when replacing a conventional belt system.