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Antonov Says that Dual-Speed Ancillaries Can Deliver a 5% Reduction in Fuel Consumption

Antonov two-speed alternator. Click to enlarge.

Simple dual-speed drives can help alternators and other engine ancillaries operate more efficiently by better matching their drive speed to the vehicle requirements and also improve the re-charging of batteries, according to transmission specialist Antonov Automotive Technologies. (Earlier post.)

The characteristics of Antonov’s mechanical module (AMM), essentially a self-controlling automatic two-speed gearset, can be tuned to meet specific vehicle requirements.

The dual-speed technology is based on a simple mechanical shift for an automatic transmission system invented 20 years ago by Roumen Antonov. The principle is to control the shift with the use of centrifugal force and axial thrust generated by helical gears under load. The systems can work as autonomous self-adapting modules without the need for more expensive hydraulic actuation or electronic control.

Mated to an alternator it provides improved alternator matching to give good charge at engine idle without incurring losses at higher engine speeds. In this application, it can also provide a reduction drive to enable a compact front mounted starter-alternator to be used for engine stop-start operation. The company, which is developing the system for OEM applications, says a dual-speed alternator designed for stop-start operation can deliver an 18% saving of electrical energy over a typical light commercial vehicle duty cycle.

It can also be applied as a dual-pulley unit to give a two-speed belt driven alternator, air-conditioning pump and water pump, whereby the accumulated energy saving translates into a 5.6% reduction in fuel consumption. This is achieved with a 2-to-1 gear ratio change at 2,000 rpm.

Ultimately, the company aims to introduce a compact unit that is mounted directly to the engine crankshaft, but this will require much greater development integration with the base engine.

Customers and legislators are placing more demands on vehicle electrical power, with lower emissions meaning smaller petrol and diesel engines, lower engine idle speeds and more stop-start systems. Even daytime headlight legislation is increasing the electrical load.

—Chris Baylis, operations director Antonov

The introduction by carmakers of belt-driven stop-start systems and other technical developments, such as downsized engines, is increasing the need for more efficient electrical systems. Vehicle manufacturers also want more engine torque at low engine speeds to improve driveability as well as better fuel efficiency.

Maximizing the overall operating efficiency with fixed drive alternators, water-pumps, superchargers—indeed any crankshaft driven or electric motor ancillary—is becoming more and more difficult. At high engine speeds this can result in unacceptable losses or even excessive speeding outside their most efficient operating range.

—Chris Baylis

Applied to an alternator, the Antonov dual-speed module can increase the electrical output for regenerative braking and reduce engine idle speed without battery charging issues. A smaller dual-speed alternator can match the low engine speed output of a larger more expensive alternator, and there is also reduced noise at higher engine speeds.

Another application of Antonov’s AMM device is to facilitate low cost engine downsizing. As demonstrated at the recent Cenex low carbon vehicle event in the UK, it can be used as a 2-speed drive with a centrifugal supercharger. The resultant higher drive ratio at low engine speeds provides a big engine feel from a small engine, allowing for less gear down changing and improved fuel economy.

Antonov is similarly pursuing the development of its mechanical module as a 2-speed electric vehicle transmission, whereby it’s either packaged into the electric motor as part of the reduction gearing, installed as a separate dual-speed unit or as part of the transaxle. The AMM device requires no external control, with its characteristics predetermined at the design stage. The high transmission efficiency of a purely mechanical system ensures minimum losses through the driveline.

Two Antonov epicyclical sets can also be incorporated as a binary system to create a simple fully mechanical fully automatic 4-speed transmission, which is suited for the low-cost cars required in third world and emerging markets. The very low costs are achieving by not having any hydraulic systems or transmission control units. Maximum efficiency is delivered by only slipping two clutches in 1st gear, one clutch in 2nd and 3rd gears, no clutches slipping in 4th gear and no high pressure oil pump.



Isn't the Telsa BEV new version equipped with a similar 2-speed unit?

This is nice and it is too bad it took awhile for someone to see the market for pushing forward development but I see this product as one addressing a declining market share - as more electrical accessories are used the application becomes limited to strictly the alternator and no longer services a/c or p/s. As more vehicles include "hybrid" components the alternator market share will then diminish. Still, probably a decent market for 10 years or so - especially while automakers scramble to gain whatever efficiencies they can.

tom deplume

This looks like something 18-wheelers could find very attractive. When you are going through $700 to $1000 of fuel day after day a 5% savings adds up quickly.


with all due respect I have trouble accepting the 5% number as reflecting a real operational efficiency. Having limited experience with charging systems and alternator cutouts I have noted that after the initial recharge of the battery after start, the alternator output is reduced ( ie efficiency isnt an issue once the battery is charged). many truck stops use external power instead of idling the engine to keep the electrics up. perhaps on hybrids there is some advantage, but in real life use i bet its under 2%.


I doubt that such a unit would have much benefit for a semi-tractor; the parasitic losses of the electrical system are a much smaller part of the total power use of a big truck, and a diesel engine with a 2300 RPM redline doesn't need to limit the speed of the accessories.


@ Harvey:

First Tesla roadster was built with a 2-speed transmission. Testing caused it to break down after 3-4 thousand miles (I don't know who designed it). Then they contracted Magna to quickly develop another 2-speed unit, and it was failing in similar fashion, so they had to abandon it and some first samples built were delivered with only second gear, ie with slower acceleration.
Soon afterwards some power transistor maker came up with a more powerful modules (IGBT), so they were able to drive motor with higher current (allowing higher torque). It allowed them to achieve desired performances (3.9 sec 0-100 kmph, and max 200 kmph) in a single gear, without need for 2 gears. To better cope with stronger currents used, they introduced a beefed up motor (again air cooled) that is about 50% heavier (now 110 lbs) that can sustain easier the heat developed under high loads.

Would Antonov 2-speed unit have worked with original Tesla design?
Don't know, probably not. To me it seams it switches gears always at fixed rpm (independent of load), and cannot be controlled easily.
And it's not known how reliable the Antonov design is.


I can see 2 possible applications for this Antonov design in EREV (series hybrid - like Chevy Volt) generator unit.

First one:
For very cold Canadian winters it would make sense to have ICE (from genset) to work in efficient idle mode (assuming an HCCI design) to provide heat for the interior and battery pack.
BTW heat pumps for homes for temps below 10 deg Cels use also a heater.
So why not use an efficiently idling engine (HCCI/diesel type) instead of electric heater, and avoid double conversion. At the same time the generator (with Antonov gearbox) would be running in its more efficient range (2-3 times the idle engine rpm, in its second gear), charging lightly. At optimal engine speed, generator would run in its first gear.

Second one, again for series hybrid:
Some Li-Ion battery chemistries have significant difference of cell voltage in fully charged and low charge states (in case of EnerDel it is around 2.6V/1.6V).
In capacitor type of storage (like EESTOR) it could be 2-3 to 1 ratio.
If Antonov type 2-speed generator is used with such EESU's, it would be possible to optimize the charging process by varying engine speed by, say, only 15% around trigger rpm for generator (to force it to change gear), based on current EESU voltage. The idea is to have generated voltage not too high above current EESU voltage.
This design would require careful study of both engine's and generator's efficiency vs rpm curves, for different loads, in order to optimize the entire system.



Tks for the info on the Telsa. I agree that on an average small or mid-size family type BEV, no mechanical transmission should be required. For PHEVs it may optimize the genset efficiency and reduce ICE wear + reduce fuel consumption?


If you want to discus with 500 other Antonov technology enthousiastics goto: http://www.antonovforum.com


To learn, to know and to see more of the Antonov technology (dual-speed and six-speed automatic systems see and read this all. Very interesting.

Video and more about the dual speed technology (two speed setup unit for supercharger).


Test driver with Chevrolet lacetti with Antonov dual-speed setup unit for supercharger system.
Lexus with antonov dual speed setup unit for supercharger.


Pictures and more of the Antonov dual-speed setup unit.
Results of torque/power increase Hummer H2 with Antonov dual-speed set



And more good videos about the Antonov automatic transmission technology.


About Six-speed automatic transmission technology and other Antonov technolgy products.


If you want to discus with 500 other Antonov technology enthousiastics goto: http://www.antonovforum.com


This is the perfect solution to solve the shortage at electric power supply by cars in idle mode or low rpm and on boats when the engine is at low RPM.

Some cars ar using two alternaters to slove the shortage of electric power. See this: http://img.photobucket.com/albums/v471/LanaFee/Dualandmultiplealternatorinstallati.jpg

The Antonov dual-speed alternator is a much better system.

The Antonov Dual-Speed Alternator set up unit system that shift automatically to the highest gear when the car/boat(engine) is at idle or low RPM. So you have a better electricity supply at idle mode with the Antonov Dual-Speed Alternator set up unit. And it shifts autoamatically back when your car/boat(engine) has reach a higher speed (RPM) See this video about the Antonv dual-speed Alternator:


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