The RVT is a radically new way of transmitting engine power, designed for unrivalled fuel and CO2 reduction and dynamics, suitable for a broad range of vehicles, auxiliaries and industrial applications.
The RVT contains no clutch or other slipping components and uses the engine at its best efficiency curve at all times. The ratio varies smoothly without any reduction of efficiency or traction. The RVT benefits from being a continuous system while avoiding the drawbacks of current CVTs.
The RVT is based on an innovative variator system which can also function as an energy saving speed variator for auxiliaries and engine driven industrial applications.
* compared to all MT, AT, AMT, DCT and CVT’s currently on the market
Optimal use of the engine
In a passenger car the high max speed ratio of 2.4 combined with no torque dip during ratio change and the fast and smooth dynamics allow the transmission controller to keep the engine always at its best efficiency curve (or lowest emission curve), even when the throttle position is varying. In comparison with a 6 speed automatic, the RVT will reduce fuel consumption with around 20% - in a driving cycle with a lot of highway - just by keeping the engine on its best efficiency curve. A further 2-6% reduction of fuel consumption is achieved by the transmission’s internal efficiency (next chapter).
High transmission efficiency
Immediate throttle response: drive away in only 58 ms
The ratio of the RVT varies within 58 ms after request. To the driver such a short delay is unnoticeable and feels as immediate. The same “delay” is measured from absolute standstill to drive away.
Never torque dip or efficiency reduction
Thanks to its unique design, the RVT changes ratios without any torque dip or efficiency reduction. Even close to standstill, at standstill or when changing driving direction, the requested wheel traction remains applied, without any components slipping.
The RVT operates without noise and vibrations:
As the engine is always used at its optimum regime, it can continuously remain at its max power level for max performance. A stepped gearbox will use the engine more or less in the region of its max power. The more gears a transmission has, the closer it can get to the optimum engine speed; it loses however efficiency and performance at every gear change.
The ECU needs no adapting
The Engine Control Unit needs no adapting to the RVT; it’s the RVT that adapts to the engine. Naturally, the advantages of the RVT allow for further optimization of the engine’s ECU.
Robust design with only few sensors & solenoids; and no clutches nor torque converter
The RVT is made of considerably less components than other transmissions: no torque converter, no clutches nor their hydraulic control and sensors, no synchronizers or synchro-activation mechanism, no gears and no piston rings. Also, the programming of the RVT controller is far less complicated than for a conventional AT or DCT.
The RVT is an advanced continuous transmission system which has eliminated the disadvantages of current CVTs. The essence of the RVT is that it enhances the engine’s performance while being a highly efficient system in itself.
A unique feature of the RVT design is that its traction wheels roll over each other in a mathematically pure way, so that traction is transferred without drilling motion, a major disadvantage of all existing CVTs causing heat and efficiency loss.
The current RVT’s max input speed corresponds to diesel engine speeds, an RVT with a higher max input speed for petrol engines is on its way. The RVT can be scaled to higher or lower power levels according to the requirements of the vehicle:
The RVT design is based on an innovative variator which can also function as a compact, energy saving speed variator for auxiliaries and engine driven industrial applications. Savings are made as the engine ànd the auxiliaries run at their ideal speeds, independently from each other. Suitable for vehicle airco’s, engine root compressors, compressors for braking, generators, tractor auxiliaries, cooling fans,...
Ratio spread: up to 4
Overall efficiency: 96.9%.
Length of a variator model with 50Nm at output shaft: 200mm
Thanks to the variator, a frequency converter is no longer needed which means considerable cost saving!
Mazaro concentrates on the RVT’s further design and development for specific applications. Mazaro calculates the mechanical aspects of the transmission and has developed the full physical model to support new designs. This model includes:
We also develop the hydraulics and model based software for controlling the transmission.
Our development and research activities have been rewarded more than once by financial support from the Belgian government.
Several test benches were made for our specific tests:
Traction test rig
This test set up is made to evaluate different materials, surface treatments, lubrication fluids and other aspects. Traction capacity, endurance and wear are measured.
The measured results of the test rig have confirmed the theoretical traction models.
For specific tribological aspects we cooperate with universities and specialized companies.
Hydraulic test set up
For the development of the hydraulic controls of the transmission a special setup was made to fine-tune the theoretical hydraulics’ model.
Transmission functionality test rig
The transmission is driven while the output is loaded by a braking torque to evaluate functionality and controllability.
Transmission performance test rig
For full torque and full power tests a specific test bench with 200 kW motors has been installed. Output speeds up to 6000 RPM can be tested.
Mazaro is an automotive engineering company that invented and patented the Reversible Variable Transmission, a new transmission for vehicles, auxiliaries and industrial applications.
Our activities concentrate on making the RVT production-ready for specific applications, consisting of the design and calculation of mechanical aspects, physical models and controls software.
Mazaro is also engaged in research and testing to evaluate components, transmissions and subsystems.
The RVT development has been awarded several grants from IWT, the Flemish government agency for Innovation by Science and Technology.
Filip De Mazière is the designer of the RVT, co-founder and director of Mazaro. He has been designing transmissions and clutches for over 25 years for major manufacturers of high-end sports cars, passenger cars, off-highway vehicles and material handling equipment.
F. De Mazière holds a Master Science degree in Mechanical Engineering (University of Ghent Belgium 1987) and initiated several patents for automatic transmissions, DCTs and off-highway power shifts some of which are in production since the nineties.
Caroline De Dijcker, co-founder and marketing officer of Mazaro nv graduated from the University of Ghent (Belgium) in 1986 at the faculty of Germanic philology and later from the Vlerick Business School.
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