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VISCOUS FAN DRIVE BENEFITS

  • More usable HP
  • Quicker warm up
  • Improved cab heating
  • Less formation of oil sludge
  • Increased Belt Life
  • Reduction of fuel consumption under comparable operating conditions of 5/15%
  • Cab noise reduced by 2/10 dB and overall external noise reduction of up to 10 dB
  • Viewed as an essential component to comply with drive by noise legislation
  • More consistent engine operating temperature and reduced temperature fluctuation resulting is less gasket problems or cylinder head cracking
  • Optimum temperature for a greater part of operating life contributing to improved durability
  • 10 deg.C region temperature hysteresis for optimum operational characteristic
  • Fully modulating drives under development have shown up to 4% further improvement and reduced disengaged speed by attention to design
  • Fixed fans take typically 5% of engine output at full load but 10/15% at part load. A VFD only engages the fan when required, which may be as little as 2% of the vehicle operating life
  • No shock-loading for optimum cooling and top performance
  • Low maintenance
  • Suitable for retrofitting to fixed fan vehicles for significantly reduced cost of operation

VISCOUS FAN DRIVE FUNCTION TEST

  1. With engine warm and vehicle secured at rest, cover radiator grill, leaving an aperture for air to reach centre of drive
  2. Start engine, allow to remain at "low idle" for 30 seconds to assure adequate oil pressure
  3. Bring engine to "high idle" condition and lock throttle
  4. If vehicle is equipped with snap action shutters, opening should occur at or before 185 F. Note opening temperature
  5. With strobe light, note input (shaft) and output (fan) speeds as coolant temperature approaches an indicated 195 F. Fan speed should peak at 85% input speed, minimum

    Note: Indicated coolant temperature should not exceed 200 F under ANY conditions. Temperatures is excess of 200 F can cause extensive engine damage

  6. Allow engine to remain at "high idle" and remove grill cover. Fan speed should begin to decrease after approximately one minute, and should eventually drop to 50% input speed, maximum
  7. Return engine to "low idle" condition. Allow to cool while running for at least three minutes before shutdown
  8. If stated fan drive input to output speed ratios were not attained, or if temperature limit was exceeded the drive is likely to need attention

MOULDED FANS

A polymer fan series is now available from Technical Services, a world leader in fan design and manufacturing technology. Current injection moulding polymer technology has made possible a series of fan designs that maximise air flow and durability while reducing weight and lowering inertia characteristics

Reduced Weight Means Lower Inertia

Up to 70% lighter than comparable metal fans, the plastic fan means faster acceleration with less static load on the bearing systems and belts of related cooling system components (fan drive, water pump and mounting hub)

Finite Stress Analysis Diagram

Designed For Durability

In addition to extending cooling system component life with lower static loads, the polymer fan material has a higher vibration damping capability. The one-piece moulded construction minimises stress points reducing vibration in the fan

Performance characteristics and tolerance limits of a variety of polymer materials were defined by engineering with a rigorous evaluation programme. Cold impact testing, hot cycle testing, burst testing strain gauge analysis and in-vehicle testing made it possible to accurately select the material best suited to heavy duty engine cooling demands. A reinforced polymer produced high strength and distortion resistance under extreme operating temperature variations (-40ºF to 250ºF)

The fans are developed with the most efficient aerodynamic configurations utilising computer-aided design techniques. These designs are developed with finite element stress analysis to insure superior strength under a wide range of operating conditions. Engineering expertise and state-of-the-art development techniques means a final production model designed to yield consistently high product integrity and long term durability

The lightweight, long-life fan can be added to your present cooling equipment or matched with the viscous drive fan for a complete, pre-matched cooling system package


THE VISCOUS FAN DRIVE


WHAT MAKES IT WORK?

  • Bi-metallic strip senses engine cooling needs and regulates flow of silicone fluid in drive accordingly
  • Fluid flow shifts fan speed and torque through all variations from low to high mode in direction response to engine temperature
  • Result: Greater cooling efficiency and economy. Eliminates " shock-loading" which can shorten belt life and increase wear and tear on engine

An incorrectly functioning drive adversely affects performance,
and could damage the engine

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