The NerraTrac continuously variable transmission (CVT) utilizes a traction drive in a traction fluid (high viscosity lubricant) that ‘solidifies’ momentarily between two hardened metal surfaces under high contact pressure, thus providing a traction force. It employs the same elasto-hydrodynamic lubrication principle used by all current automotive CVT transmissions.

The NerraTrac CVT uses a commercially available traction fluid, such as Santotrac, from Santolubes. Refer: https://www.santolubes.com/products/santotrac/

A 1985 NASA paper on the Design of Traction Drives provides a credible reference on the technology principles. Refer to: https://ntrs.nasa.gov/api/citations/19860004265/downloads/19860004265.pdf. Well established and proven technology principles.

The NerraTrac CVT enables features such as:

• Automated ratio control
• Geared regeneration
• Full CVT capability under all load conditions
• 91-94% efficiency (MATLAB Simscape simulation, 374% ratio)
• Shaft driven, fully enclosed system; practically zero maintenance
• Simple, durable, lightweight design (2.3kg or 5.0lbs without external casing)
• 370% ratio range (198mm diameter disk)
• 510% ratio range (248mm diameter disk)

Benefits include:

• multiplication of motor torque
• motor down-sizing (optimization)
• maximising motor efficiency
• maximum current reduction
• high speed capability
• extended range
• limited to zero maintenance
• no cooling issues
• silent operation

Scalability:

• 9.2 kW (current ebike CVT design):
  If the input power is 25 Nm, it will be suitable for an 9.2 kW ICE or an electric motor at 3,500 rpm.
  Power (Watt) = 0.105 x Nm x rpm, therefore, this will result in Hertz contact stresses of around 1.35 GPa, thus, it can be manufactured using relatively low cost EN36B steel (case hardened to 60 HRC).
• 15.8 kW:
  As per above example but at 6,000 rpm input, will result in 15.8kW
• 34.6 kW:
  As per the first example, but using special steel* for the disk and rollers that can handle 2.7 GPa (55 Nm) at a high duty cycle. * Note: an example of suitable steel is KUJ7 manufactured by Koyo.
  This will result in 20.2 kW at 3,500 rpm and 34.6 kW at 6,000 rpm.
• Further scaling (bespoke):
  The NerraTrac CVT can be further scaled by increasing input rpm above 6,000 ≤ 21,000rpm.
  Secondly, by applying the variations on the design space & relationships e.g. larger rollers, a larger disk etc, according to the requirements of specific applications.

The NerraTrac CVT represents an adaptable platform technology

Suitable a transmission for light electric vehicles and ICE vehicles such as:

• motorcycle scooters, mopeds, three wheelers
• ‘pod’, microcars, LEVs, autonomous delivery vehicles (ADVs)
• UTVs & ATVs
• ebikes, ecargo bikes
• golf carts, lawnmowers etc
• and all rubber belt CVT applications

Also suitable be for industrial applications including:

• Pumps
• Compressors
• HVAC
• Geared motor drives
• Conveyors
• Appliances such as washing machines
• As a Variable Speed Drive (VSD) alternative
• Artificial lift (oil & gas)

CVT vs VSD advantages include:

• multiplication of motor torque
• speed control
• motor optimization
• motor size reduction
• system start-up control
• energy/electricity optimization and start-up current spike reduction