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Antonov's 3-speed transmission for electric vehicles boosts efficiency by 15 percent


July 3, 2011

Antonov has developed a 3-speed transmission for electric vehicles from the ground up

Antonov has developed a 3-speed transmission for electric vehicles from the ground up

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Electric vehicles have been a reality for more than 100 years, but it's only in the last decade or so that the world has truly woken up to their potential as a viable, cleaner urban transport alternative to their combustion engined cousins. During this EV renaissance much of the focus has been on developing improved power sources like batteries and fuel cells in order to deliver the range and performance consumers have become accustomed to during the age of oil. Transmissions on the other hand, despite being so important in the ICE space, hardly rate a mention because the wide torque curve of electric motors makes them largely irrelevant. It could be time to rethink that approach according to U.K. based engineering firm Antonov. The company has produced a 3-speed transmission designed specifically for electric vehicles that promises to bring significant efficiency gains and a better driver experience. The company's Business Development Manager Dave Paul outlined these benefits in a presentation at the IDTechEX Electric vehicles conference this week in Stuttgart.

Why use a 3-speed transmission for electric vehicles?

Internal combustion engines typically reach maximum torque at between 3000 and 5000 rpm, so a gearbox is needed to keep the engine in this operating range as the speed of the vehicle increases. Electric motors on the other hand have full torque at 0 rpm and a much wider operating range. That's why most EVs have a single speed - or in some cases dual-speed - transmission. Despite this, the efficiency of electric motors still varies at different speeds - they operate at a peak efficiency of around 90 percent but this can fall to 60-70 percent, particularly at low speed. The question is whether or not it's worth adding a multi-speed transmission to the EV drive-train to optimize efficiency at all speeds. According to Antonov, the answer is definitely yes.

Benefits of the Antonov multi-speed transmission

The Antonov system grew out of the Jaguar Limo-Green project in 2009. Antonov was initially asked to provide a fixed ratio transmission for this range extended series hybrid, but it was decided to look at additional gears with the aim of improving off-the-line performance and top speed. It worked. In testing, the 3-speed transmission improved efficiency by 14.7 percent while delivering the same performance of the base line vehicle, which translates to greater range or alternatively, a smaller battery pack. On the flip-side, it can deliver better performance at the same level of efficiency. The unit was also compact enough to drop into the existing transmission tunnel.

Almost 15 percent. That's a significant figure, but Paul says that it can also bring a raft of other benefits to EV architecture. The addition of a multi-speed transmission means a lower torque motor can be used which results in cost benefits and an overall reduction in the weight of the powertrain. It can offer better launch acceleration, lower noise and a higher cruising speed, while the hill climbing ability of utility vehicles can be improved.

Paul also argues that integrating the Antonov transmission can result in simpler, lighter and cheaper power electronics, and because the motor can be kept within its optimum speed range there's less wear. There are also gear overlap benefits compared to a 2-speed transmission, meaning that not as many gear changes are required at mid-range speeds.

One of the most interesting benefits is the potential to link the system to telematics so that the optimum gear can be selected when, for example you are approaching an uphill stretch of road.

Similarly, a "limp-home" facility could be incorporated to maximize efficiency over performance as the telematics system recognizes that you are likely to run out of juice before you reach your destination.

Another benefit to the overall efficiency of the vehicle is the ability to use first gear to maximize the regenerative braking.

The transmission has a "fairly conventional" twin shaft layout and uses two lubrication pumps - one mechanical, one electric - and a dual clutch for seamless gear changing. It could also be modified to become a 4-speed.

Antonov is currently involved in a project with Smith Electric Vehicles in which five prototype electric delivery vans are being developed for commercial applications.

This week the company also took out the IDTechEx Electric Vehicles Land Sea Air "Technology Award‟ for the most significant EV technical development over the past two years.

So why haven't we seen three (or more) speed transmissions in electric vehicles before? The idea goes against conventional thinking regarding electric drive systems and Paul believes that engineers engaged in EV development have thus far kept a narrow focus. Perhaps no-one realized the significant difference a multi-speed transmission can make ... we'd love to hear your thoughts in the comments section.

About the Author
Noel McKeegan After a misspent youth at law school, Noel began to dabble in tech research, writing and things with wheels that go fast. This bus dropped him at the door of a freshly sprouted Gizmag.com in 2002. He has been Gizmag's Editor-in-Chief since 2007. All articles by Noel McKeegan

Gearboxes are old hat. Variable pulleys and a drive belt are what\'s happening.


if there is an idea, then quite often another point of view can see another opportunity within that idea., This 3 speed transmissionn seems to be something all the others missed so good luck to Antonov


The real question is what makes this transmission superior to other off the shelf transmissions for electric vehicles.

There is no evidence that battery based electric cars are cleaner that IC, steam, pneumatic, or sterling cycle powered cars. The electricity must be generated somewhere and today that mostly means coal. And lets not forget the battery is energy intensive to manufacture, and will have to be replaced in 4-6 years.

If you want to have practical electric cars, provide on the road electrical delivery for main roads. I prefer a non-physical contact induction system built into the road surface, but overhead electrical wires like most electrified railroads use, and for the life of me I don\'t understand why the NY city subway doesn\'t may be better, but it does not have the \'cool\' factor.


Let\'s just not get carried away with multiple speeds. Electric motors do after all have insanely broad power band characteristics. And I would say that motor and power supply designers have not exhausted their bag of tricks to eliminate some of the efficiency losses that occur at the varying speed/power combination of single speed drives. . Until then, two speeds is probably enough to increase efficiency. Three probably doesn\'t get you that much more in the efficiency game, but I can see how it might enable you to shift gears less often in typical mid-speed traffic situations. Shifting gears smoothly is after all one of the greatest challenges in making an unobtrusive transmission and it\'s taken the auto industry 100 years to finally get that right for the most part. The quest for smooth shifts is what makes transmissions so fiendishly complicated. More gears mean more gear switching. So maybe it might be well to stop at 3, shall we? Unless you\'re traveling 200km/h or something on a regular basis, which is not really the thing to do on limited battery power at this point!


Sounds like win-win engineering at its best....

Dave Brumley

Kudos to this article for great technical coverage of the benefits and features of the system. Other off the shelf EV conversions I\'ve seen even integrate a manual transmission... this is a big positive step.

It\'s great to read an EV article without use of the words \'Co2\', \'green\', \'eco-*\',\'climate\' or similar hogwash intended to dumb it down for teens.

Good tech standing on its own without greenwashing... the way it should be.

Todd Dunning

one of the major benefits of electric vehicles...is their simplicity and few moving parts, reducing maintanance cost.

transmissions sound like a no-brainer, but if you assume that battery power is going to increase and that motor designs will also increase, than the cost of mass producing an object that is only going to add further maintainance and lubrication costs to your car is not necessarlily an easy sell.

Facebook User

Great to see an article with some depth on something other than EV basics.

Kim Holder

Prove the added efficiency and include it... I am still waiting for the VW 1L... who needs electric cars with this vehicle.

Mark A

People doing their maths, and finding ways to capitalise on obvious short comings.

Very good.

Mr Stiffy

What is the additional cost for this 15% savings, I doubt the 15% savings comes in any driving condition so what are the conditions that get this savings? This transmission will have to handle high torque if this is for a performance vehicle i.e more expensive. Is this transmission a good idea, I am sure in some situations it will be worth the added cost, weight and complexity.


I would have thought a constantly variable transmission would have been a better idea(?)

Ron Raines

One big advantage of electric motors is that you can drive the wheels directly. Most EV designs these days use two or four wheel motors. This saves weight and friction associated with differential gears, propshaft couplings and half shaft couplings. So coming back a step and using a single motor with a gearbox must mean back to using a diff etc. Any real-worlkd gearbox must have a lot of friction and thus loses power at the wheels. The proper comparison would be between a single motor with gearbox driving propshaft, diff and half shafts, and a 2 wheelmotor design, not forgetting the overall weight differences and thus acceleration and endurance.

Chris Knowles

Too much drag, impossible. Try a variable ratio belt would give better results. But even better would be an efficiency matched electrical variable circumference drive.. no gears just magnets and electromagnets..

Brian Wills

The best transmission is oil because it can be variable. The oil can be pumped by electric or fuel. The wheels need less spring weight for a smoother ride and control. There is an engine design that has no crank shaft that powers the oil and also charges electricity while running. This design allows for long distance driving while using electric and fuel (even hydrogen).


Yes, despite the nay-sayer\'s concerns about complexity and maintenance, its a good idea to have selectable drive ratios and, unless you\'re putting a motor at each corner, you will have to have at differential or something like it. The alternative would be to have two electric motors each, with its own set gear ratio. They could drive the car together or separately depending on the speed and power the driver is calling for. For that matter, one could be at the front and one at the rear, RWD might be preferable for the open road. Surprised it hasn\'t been done - best of both worlds.


robinyatesuk2003 , your comment is the typical result of the job that the \"oil oriented\" mass media continued to substain. i think such approach to the problem is substantially wrong. Yes is true , big part of the electric energy is produced with oil... but how? is more efficient ONE strom central production of some million of little engine distributed everywhere in planet? think that. one regenerative turbine in one strom centralized production can have one efficiency of 70% and work at constant rpm. one electric engine have one efficiency of 90%. so 90% of 70% is how much? and this result can be improved with a most massive use in future of renowable source. such changement have no benefit if the cars still burns oil directly. now compare with the actual cycle. cars directly burn oil. how much can be improved the efficience of the gasoline engine? between 25% to 0,1% when u wait behind other veicles and you dont move and just produce heating. if everybody runs diesel can be between 30-35% to 0. so the cycle oil electric is at least two times for efficent than the full gasoline or full diesel cicle. and dont forgot one thing... reduce oil consuption it mean reduce the pollution caused by the PRODUCTION of gasoline that is absolutely a NOT EFFICIENT process. at the end...a lithium iron phosphate battery have one life ot 2000 cycles with a 80% residual range. it mean one life at least of 8 years with intensive use. so i think switch to electric is quite convenient...

Motorcafè Due

I can see the performance gain from a mechanical gearbox and some efficiency gains at very low speeds... but I struggle to believe that a motor designed with more \"poles\" can\'t achieve the exact same performance without the mechanical losses.

What are the losses introduced by this gearbox? Maintenance & life expectancy?

Electronics, specifically power components, can be added to a design for very low costs. The control topology of the added components would be complicated, but relatively low technology risk, while adding to the overall reliability/redundancy of the system.

I think we\'ve just scratched the surface of motor technology... there are major improvements yet to be developed that will likely obsolete the gearbox AND the single motor designs that are a legacy of the IC era. Lightweight hub or wheel motors will re-invigorate auto designers while providing tremendous safety and performance improvements. Putting 2 or 4 gearboxes on the next generation is highly unlikely.

Simons Engineering

Great, great, great !

Let\'s get rid of those IC monsters, then we can all savour the different flavors of EVs. As some other commentator remarked gears with electric motors is maybe superfluous when you consider the usage considered in vehicle\'s normal driving conditions. But then why not..

I also would like you to remark that just we are reaching that tipping point, we start to hear too often those who try to tie the destiny of the EVs to coal powered electricity or to Fukushima catastrophe, or even throwing out polemics about the dangers of batteries, etc.. This is what they want you to believe, they (7 out of ten most powerful companies on earth..) will not let themselves disappear like that, without giving a fight, after all.

Nobody is urging you to jump in nuclear power to feed your animal. Renewables are the killer app for EVs, and EVs are killer app for renewables. One thing is for sure: earth can no longer sustain combustion monsters\' expansion. FULL STOP.


What is the TOTAL efficiency of Electric vehicles with these gears, . . . 105% efficient? ? ? ? . . . 96% efficient? ? ? ? . . . 91.5% efficient? ? ? ? if Gasoline vehicles are 25-27% efficient, and . . . if Electric vehicles are 90% efficient, and . . . if these gears make Electric vehicles 15% more efficient.

I think people and companies seek to keep getting a piece of the pie. Transmissions are probably usually a negative for electric vehicles. The best answer is in reducing the number of cars allowed on the roads and encouraging the use of bicycles or at least small motorcycles or scooters. Really there is no technology or group of technologies available to give us as great of a solution as we need. And with health declining in the US we need to be walking a lot more anyway. Jim Sadler

Electric car conversions have been going on for decades using the original transmissions that came with the converted cars. Many manual transmissions were used with 3, 4 or 5 gears. I think the improvement stated in the article is possibly over optimistic. They are making headway with electric cars in Oregon, Washington states. They are installing charging stations by the dozens. It is possible to drive an all electric car for about 3 cents per mile. The big killer at this time is still the cost of replacement batteries. This will improve in time with all the automakers getting into the game. Range will improve and charge stations will become more available. It is amazing how much resistance is developed by big oil because they would hate to see their market dry up before the oil runs out. Think of this: If our tax dollars stopped paying big oil welfare, and stopped paying farm supports, the free enterprise system could afford Social Security forever as well as help electric car development. Close to $800 Billion goes to Big Farm and Big Oil each budget. What do you want $5 gas or $0.03 per mile and lower taxes. Think of it, taxis in New York charging batteries at night to run the first 100 miles or more for $0.03 per mile. It will happen! I will now get off the soap box. Thank you.


I can appreciate any improvements to a drive system but believe that mpg for electric and ICE vehicles could be more effectively improved by aerodynamics and weight loss. Stamping out a a good aerodynamic shape to improve efficienies of over 100% should be done for better air separation and flow over the skin of most vehicles. This area of development has been seriously neglected.

As cars become lighter, compensation must be made for weight loss during a collision and this can be done by the use of foam steel to better absorb impact. The use of foam steel should enable producers of vehicles to use thinner frame materials since some of the shock to the frame would be absorbed by the foam steel.

Adrian Akau

Take a look at www.torotrak.com This is a device that is quite amazing. No more gears!


Wow!!! First time I\'ve ever seen Mr. Stiffy post a positive comment!! This must be (and I concur) good technology! lol.

Jeremy Nasmith

Yes the electric engine has a wide torque band and considerable down low torque. This is output though and as you don\'t get something for nothing (particularly with electricity where it is far easier to track power flow using pythagorean formulae). I think to concentrate wholly on output lacks comprehension and focus of what is happening in power transformation (mechanical/electrical, input-output-losses, torque multiplication, torque current ratio, components of power input, components of power output, moment multiplication/division etc). I think that an, in-line, omni-speed, \"gearbox\", is probably the best form of transmission and this \"gearbox\", should not contain gears as the losses due to axial forces, in my opinion, will prove to be unacceptable, as losses are losses and must be eliminated, minimised or be able to be tolerated. In my opinion the Antonov gearbox is a very good step in the contemplation of the widespread application of electrical engines but it is not avant- garde, more the first sensible step in getting up to speed on a mechanical/electrical/logical perspective on this conundrum. Glen Court.



This is an interesting concept. But I remain hesitant. There is a sense that Antonov is expressing some success at improved efficiency and performance, however the article is a dismal failure at explaining what this is.

An improved efficiency of 14.7% is claimed, but what is the baseline. Is this 14.7% of 70% electric motor efficiency (80.29% overall.) Or is this 14.7% improvement of some drive train efficiency or is it something else entirely. What it can\'t be is a 14.7% improvement of overall vehicle or motor 90% efficiency as this would be over unity or 103.23%???

This then points to the problem of working to make an electric drive train more efficient. There is little room for improvement and we need to factor in the loss in efficiency that is produced by installing this transmission. I would expect the drop in efficiency from the transmission to be approximately 3 to 5% overall. http://www.fueleconomy.gov/feg/atv.shtml Is this also factored in to the mysterious 14.7% improvement? All writers may not be technically inclined but this article fails to cover the fundimentals.


Greetings! Talk about \"forward thinking\"! Best wishes of continued success! I understand that this principle is being considered by electric motorcycle companies as well! We do need to move Forward! GOD Bless!


This great news for the auto industry and the environment. But, realistically, it will be 10-20 years before a fully functioning car becomes the norm.

In the meantime, here is the reality. Gas prices are at the all-time normal price and many are hurting for this effect, especially those companies that use massive amounts of fuel.

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The ingredients and benefits consist of combustion catalyst, detergents, lubricants, fuel stabilizers, polmerization retardant and dispersants, rust and corrosion inhibitors and demulsifiers. Simply, XFT really works and works very well. It\'s patented, and registered with the U.S. Environmental Protection Agency. Just 1/4-oz treats 20 GALLONS - remarkable. ww w.gosyntek.com/virtualworld has a ton of details.

Liquid Gold

I noticed several questions about the improvement in efficiency and it made me wonder also, so I went and re-read the article. The article points out that the efficiency is around 60-70 percent at low speeds and this is the reason for adding the gears. It seems quite plausible that you could get a 15% improvement at 60 or 70 percent efficiency. What is not nearly as clear is what kind of improvement you would get in standard usage. This is much like a gas vehicle in that it gives you one mileage if you go long distances at reasonable speeds and another if you spend all your time in stop and go.


As much as 40 years ago while studying the use and operation of electric cars I thought that they should use some kind of gearbox to increase their efficiency and not overload the batteries so much, as that is what degrades and reduces the life of the batteries.

John Christian

The idea of coupling a system for converting torque / speed / torque no doubt provides operating optimization of the electric motor at its optimum range, reducing energy consumption and avoiding excessive heating and premature wear of the electric motor. I believe that the best efficiency curve is achieved using the CVT system (Continuous Variable Transmission). Also, this system provides a good distribution of mass in the hybrid vehicles. This changes, substantial and positively the internal design of the car.


Anyone interested might also find this interesting: http://www.fbperformance.com/page.asp?get=42&t=Bottom2 Transmission need to be designed upon the mass they will be moving, the RPMs of the motors, and the motor characteristics. The link above works well for vehicles under 6,000 lbs using inexpensive series wound DC motors and controllers...

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