Our products are only available under a global license arrangement. Please contact our SALES team if you would like to discuss license options on any of our product range.

Commercial Vehicle Fan Drive (CVFD)


Some people will struggle to accept the test figures for the Fluid Coupling application as a highly efficient hydraulic fan drive for the cooling commerical vehicles, (see download on left of page), until they can fully understand how the fluid coupling actually works and/or see it for themselves. The Fluid Coupling cannot be viewed as a pump because the majority of energy transfer is through pressurized oil forcing the ring and output shaft to rotate. Yes, some oil can be bleed off to reduce torque and/or output speed but the majority of power is from compressed oil on the ring contour forcing the ring and output shaft assembly to rotate.

In hydraulics there are 2 inefficiencies, Volumetric and Mechanical.

Volumetric is how much internal leakage there is from the pressure areas to lower pressure areas. We have reduced this leakage by improving tolerances and using thicker oil. It needs to be noted that when pumping of oil in these couplings occurs it is at the differential speed of input and output, for example 1400 rpm in and 900 rpm out can be viewed as a pump operating at 500 rpm. Because the relative speeds are low, but centrifugal forces remain high, the manufacturing tolerances can be reduced. As the relative speed of the pump is low, inlet issues with high viscosity oils is not a problem.

Mechanical inefficiencies are the frictional forces between the rotor, vanes, ring and pressure plates (bearing efficiency has been ignored as a vane pump has balance pressure quadrants producing no side loads and uses low friction ball bearings). In a standard vane pump this is a loss of power as the ring and pressure plates are stationary, however in a coupling where power is being transferred through to the rotating ring and pressure plates from the rotor and vanes, it actually improves our efficiency by assisting drive. IE: Any frictional forces help to drive the ring and output shaft.

Pressure Controlled Coupling

The Pressure Controlled Coupling speed is controlled by bleeding some oil off at a controlled pressure. This bleed off oil is a loss of power, however, in a fan drive, the power required is the cube of the speed so as speed reduces the pressure greatly reduces and the frictional gains spoken about above are a larger proportion of the transferred energy further reducing the required pressure. The higher the volume of bleed off volume the lower the output speed, the lower power the fan draws and pressure becomes even less with friction supplying a larger portion of the power, hence the high efficiency.

Variable Speed Coupling

The Variable Speed Coupling speed is controlled by bleeding some oil off through a variable displacement motor that is mechanically connected to the coupling output and fan drive shaft. By setting the variable motor swash angle at zero, no oil can pass through it. As no oil can escape from the coupling pressure chambers all power is transferred from the rotor and vanes to the ring contour and output shaft assembly via compressed oil. This offers maximum speed to the fan blade. The efficiency here is only affected by internal leakage and as with the above the frictional forces are helping to rotate the output shaft assembly. Effectively the variable motor does nothing in this mode, but as the displacement is increased two effects occur. Firstly the oil is bleed off from the coupling and metered out across the motor reducing output speed. This energy is not lost as the motor is connected to the fan drive shaft. Secondly the total displacement is now the coupling plus the variable motor displacements. The fan speed having reduced requires less power, as discussed earlier, the torque requirement has reduced and we have increased displacement which greatly reduces the pressure requirement. This greatly reduced pressure reduces the internal leakage and frictional forces are still helping to drive the fan, hence the high efficiency.

This new technology can be difficult to comprehend, and if you are still not convinced, please contact Rob Price ( or on +61 (0)7 3267 0065) with any questions or to organise a visit to our facilities for an in depth practical demonstration.

For an Information Pack including operational DVD on the Heavy Commercial Vehicle Fan Drive(CVFD) system, please contact the Mathers Hydraulics SALES team or you can view a video on the Commercial Vehicle Fan Drive system on our You Tube channel. Just search for 'MathersHydraulics'.

PATENT NO: US20130067899A1,CN102753851A, EP2501950A2, WO2011061630A2, WO2011061630A3


FPMC 2014 September 10-12 - University of Bath 01/05/2014 pdf

An Efficient Fan Drive System Based on a Novel Hydraulic Transmission.

Mathers Hydro-Mechanical Transmission - Striking The Right Balance 01/05/2014 pdf

An article by Jack Burke in the Diesel Progress magazine, on the Balance

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An article by Paul Dvorak, in the WindPower Engineering & Develo

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Awarded 2 year Research Grant by CCEFP
26/03/2014 pdf

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Event Hosted by Engineers Australia 03/11/2011 pdf

Event Hosted by Engineers Australia  Norm Mathers - Guest speak

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Discussion on improving cooling efficiency and ambient capability of hea

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Investment Opportunity

All investor enquiries should contact, in the first instance.

Due to its potential growth and requirements for future capital, opportunities are available for sophisticated investors who wish to become involved at the introductory stage of this revolutionary new patented technology.

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Distribution Opportunities

All OEM and manufacturer enquiries should contact, in the first instance.

For OEMs and manufacturers interested in trial programs, please register your details below. Please note that Mathers Hydraulics Technologies has entered into trial programs in waste collection, power steering and tipper/dump operations with both pump and fan drives and is interested in additional partners for 2013 and beyond.

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Research licences

Research licences for transmissions using the Mathers’ hydrostatic torque converter and torque amplifier are available for research institutes and major transport  and machinery companies.

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