Antonov Says New EV Transmission Technology Is Scalable to Wide Range of Passenger and Commercial Vehicles
13 September 2010
UK-based automatic transmission specialist Antonov, which is currently developing new gearboxes tailored specifically to electric vehicles to improve their performance and range and ancillary generators to improve low speed electrical power, says its high efficiency transmission systems are scalable for any torque applications and therefore beneficial to a wide range of passenger and commercial vehicles, which are increasingly employing electric drive systems.
Antonov will showcase its new and advanced 2-speed and 3-speed technology (earlier post) at the UK’s low carbon vehicle event LCV2010 being held at Millbrook Proving Ground on 15-16 September 2010. Detailed 3D stereolithographic models will be on display of both the 2-speed and 3-speed transmission technologies.
3-speed. The first application of Antonov’s 3-speed powershift transmission intended for traction motors is scheduled for evaluation early next year in the Jaguar Limo-Green electric vehicle research project. The development of this layshaft gearbox, which features two clutches for zero torque interrupt, is part funded by the UK TSB to design and develop a high efficiency transmission for electric vehicles.
Looking at additional vehicle applications, Antonov says the technology has strong potential for further development as a 4-speed transmission, with virtually the same packaging, for even greater efficiency.
Our new 3-speed transmission can to be tailored to suit different vehicle duty cycles. For increased passenger comfort we could for example programme the transmission to remain in second gear while the vehicle is stopping and then select first gear while the motor stationery.
Antonov has developed in-house control software which provides full control of the gear-change strategy, enabling accurate energy management of the vehicle’s battery. We are also particularly pleased with the seamless powershift system, which not only meets the high level of refinement required for passenger cars, but is also relevant for example to the comfort of passengers using public transport buses particularly if passengers are standing. Another ideal application would be an all-electric taxi.—Simon Roberts, Antonov’s chief commercial officer
Another feature of Antonov’s all-new transmission system is a novel hydraulic circuit, which has the potential of being integrated with an oil-cooled traction motor. Electrical machines can generate a lot of heat, and this would provide an effective means of cooling the motor whenever the vehicle and motor are stationary.
The virtues of downsizing and de-speeding in pursuit of increased mechanical efficiency apply to electrical machines just as much as internal combustion engines. Size is everything and smaller electric motors are better for powertrain efficiency, overall vehicle performance and packaging. A powershift transmission with its choice of multiple gears allows an electric motor to operate within its most efficient speed range, effectively increasing the performance and range of the vehicle whether crawling through traffic or cruising along a motorway.—Simon Roberts
2-speed. The same basic principle applies to its compact epicyclic gearbox intended for the development of more efficient ancillary motors and generators, including the 2-speed 24-volt alternator being developed under an engineering contract awarded by the UK Ministry of Defence (MoD). Smaller and lighter electrical machines use less material and are easier to package. They also require smaller batteries and can manage with less expensive power electronic devices.
In its low speed range, Antonov’s 2-speed alternator can match the output of a much larger and more expensive single-speed alternator. It has the potential therefore of replacing multiple alternators that are often required for heavy-duty military and commercial vehicle applications, the company says. Increased electrical power on demand at low engine speed ensures optimal battery charging and permits additional electrical equipment to be specified on the vehicle. Full electronic control of the speed change is implemented through an active clutch mechanism.
The development project has been undertaken in partnership with a major manufacturer of alternators and starter motors and with the design concept already signed off the work has moved rapidly into the area of detailed engineering design.
This seems to refute the belief that electric motors and generators have constant (flat) torque/power generation regardless of their speed.
In practice, electric traction motors torque and e-generators power yield can be optimized with the use of electronically controlled variable speed transmissions. (so can new Jet Engines). Since such unit has an inherent initial and on-going maintenance cost, many electrified vehicle manufacturers will avoid their use to keep cost and complexity as low as possible, specially on lower cost vehicles. Higher cost vehicles could use such transmissions to increase performance.
Posted by: HarveyD | 13 September 2010 at 01:07 PM
In what century did the development of a 2/3 speed transmission become News worthy?
Posted by: dursun | 13 September 2010 at 02:14 PM
Power and torque are relatively flat with electric motors, but efficiency is not. When you start out from a stop with no transmission, the motor can provide the torque, but the efficiency drops way down. The batteries do not like massive current draw either.
Posted by: SJC | 13 September 2010 at 04:04 PM
Besides allowing the motor to operate at closer to optimum efficiency, will these transmissions not also give electric vehicles higher top speeds?
Posted by: Travis | 13 September 2010 at 09:58 PM
AC motors and AC based systems are more efficient and have been used for long time for city and high spead rail transport. What is the point sticking to the DC traction and DC-DC convertors? In AC system you have possibility to vary frequency and therefore regulate torque/efficiency in relation to spead.
Posted by: Darius | 13 September 2010 at 11:02 PM
Power is the product of torque and speed. "Power and torque are relatively flat with electric motors" is self-contradictory.
In practice, motors are limited by peak current (which fixes the max torque) and peak voltage (which fixes the maximum full-torque speed). Mechanical limits (shaft strength, hoop strength of rotors) may also come into play.
Posted by: Engineer-Poet | 14 September 2010 at 10:19 AM
Some people are more interested in criticizing than contributing.
Posted by: SJC | 16 September 2010 at 09:53 AM