Conventional transmissions employ a gearbox as the essential link between the power plant (engine) and drive wheel assembly. A clutch is necessary for power to be transferred effectively to the wheels.
This is most commonly done via tooth gears arranged in a number of fixed-ratio gearsets with each gearset operating according to its own fixed ratio. Alternatively, in variable-ratio transmissions with no fixed-ratio gearsets, a clutch is still required because the transmission cannot achieve powered neutral. This means that existing variable-ratio transmissions cannot handle high torque and explains why high-torque applications (such as heavy commercial vehicles) use fixed-ratio gears.
d-Drive™ is quite different. It is a new kind of transmission (driven via the planet gear in an epicyclic gearset) with no clutch.
This is what makes it unique and is the basis for our initial patent. There is no need for a clutch because power source (input) and drive (output) remain fully engaged at all times.
d-Drive™ is infinitely variable across the full range of the device and not limited to a finite number of fixed ratios.
With d-Drive™ there is true powered neutral capability – the device moves seamlessly from forward through neutral (stationary) into reverse & back again.
d-Drive™ can use a single gearset to replace the multiple gearsets of a conventional transmission – power source (input) & drive (output) remain fully engaged at all times.
With d-Drive™ motive power and torque are transmitted through tooth gears – there’s no belt or toroid or other smooth surface & therefore improved torque with no slippage.
This means that d-Drive™ is ideally suited to deliver torque, even from stationary, for the most demanding operational requirements – potential torque capacity is, theoretically, unlimited and constrained only by the physical properties of the tooth gears employed in any given application.
d-Drive™’s suitability for high-torque applications is reinforced by the additional ‘torque boost’ functionality which is the subject of a separate patent application – see under ‘Intellectual Property’ below.
We believe this overall capability (no requirement for a clutch; powered neutral capability; transmision via tooth gears for maximum torque delivery) is not only unique but revolutionary in its value proposition.
In the automotive application currently under development we are targeting significant improvements on conventional transmissions as outlined below.
- fewer component parts – no clutch
- fewer moving parts – engaged tooth gears only
- reduced weight – no clutch & only one gearset
- reduced friction & heat generation – limited number of moving parts
- reduced wear – limited number of moving parts
- improved transmission efficiency – infinitely variable ratio changes across the full range of the device
- reduced energy consumption – material fuel savings
- reduced weight – significantly fewer components & correspondingly reduced bill of quantities
d-Drive’s key differentiation and value proposition can be summarised as ‘high torque capacity coupled with optimum engine efficiency at all times for both improved fuel economy and reduced emissions‘.
The intellectual property rights for d-Drive™ were formally transferred by Steve Durnin to VRT on its incorporation.
Intellectual property comprises principally patents, pending applications and related rights to apply for patent protection but also includes design right, copyright and knowhow.
The original patent application (PCT/AU2008/001442) was made in 2008 and has now proceeded to grant in a number of countries including the USA, the UK, Germany, France and Japan; it is still progressing through the examination phase in others.
A further patent has been applied for on the provisional basis of application although the application (2015902548) has not yet (July 2015) been published. The claims relate to a control function offering independent variability of speed and torque delivery for any given input speed from the power source – we call this ‘torque boost’.
Further patent applications will be made as suitable opportunities are identified. Certain aspects of the overall technology have also been identified as having patent potential will be further assessed at the appropriate time.