| Transmission technology company Nexxtdrive is developing its epicyclic transmission technology to form a variable speed power take-off (PTO).
The first application will be in engine cooling systems for large commercial and off-highway vehicles which can account for up to 10% of fuel consumption.
This is because the cooling systems have to be sized and geared so they provide adequate cooling even when pulling heavy loads up hills with no wind blowing on the radiator and are over-geared for less strenuous conditions.
Nexxtdrive’s technology takes the power from the engine and passes it through an epicyclic transmission which combines it with the two built-in electric motors. When both motors are inactive, no power is transferred from the engine to the PTO driveshaft, creating a “clutchless neutral”. However, engaging one of the motors as a generator and feeding its generated electricity to the other allows control over the speed and torque of the driveshaft to be precisely controlled.
It is designed so that the electrical system is locked out at the most common operating speed, transferring all the system’s energy through the mechanical gearing. In this application the company expects to produce fuel savings of around 5%.
The electric motor/generators can be increased in size to replace the vehicle’s starter-motor, offering stop-start operation or basic hybrid drive for further full savings.
The PTO could also be applied in agricultural vehicles to drive an external device at a speed independent of the vehicle’s engine speed.
A Tier One supplier and some OEMs have shown interest in the concept, which could also be used to power air conditioning compressors in large cars. The company has produced a prototype and will be working with interested parties to develop more.
|
|
|
