Antonov seems to be taking this dual-speed thing quite seriously, with a new range of gizmos that take advantage of mechanical-based gear shifting.

Their latest idea is allowing belt-driven devices like alternators, water pumps, air-conditioning systems and other engine ancillaries to be driven by two-speed systems. A two-speed planetary gearbox with one step-up ratio and one direct ratio is mounted at the engine crank. At low engine speeds, the step-up ratio is used, and at high engine speeds, it is not necessary to drive ancillary devices faster than is needed so the direct ratio is used to improve efficiency.
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Antonov says adding this gearbox will only cost about US$100 and can be used with existing components. Cost is kept low because this planetary gear system is mechanical and does not use external electronic controls or hydraulic systems.

We previously saw Antonov advocating the use of a dual-speed supercharger which allowed boost to be delivered effectively over a wider range of engine speeds.
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UK: Antonov announces dual-speed drive for engine ancillaries
By Michael Murphy
26 May, 2008
Source: Automotive World

Antonov has announced several applications of a simple dual-speed drive unit that can help make vehicles more fuel efficient. The dual-speed drive units reduce fuel consumption by allowing alternators, water and air-conditioning pumps, superchargers and other engine ancillaries to operate more often in their most efficient speed range.
The technology is based on a simple mechanical shift for an automatic transmission system invented 20 years ago by Roumen Antonov. The vehicle technology company named after him now has a dual-speed supercharger and a self contained dual-speed pulley drive already in production and other applications in development.
Antonov expects that the highest volume application for the technology is in engine ancillary drive systems. Antonov has integrated its dual-speed drive unit into the pulley located at the front end of an engine crankshaft, which drives auxiliary units such as the water and air-conditioning pumps and electrical alternator. The ability for the drive unit to operate as a passive device without the need for external electronic controls or hydraulic systems is a major cost-reducing benefit. There is also no need to modify the base engine, making the drive unit easy to apply to existing powertrain systems.
The dual-speed front end accessory drive employs a planetary gear set to enable either a direct or step-up ratio. In this configuration, smaller and less expensive alternators, water and air-conditioning pumps can be fitted. These ancillaries achieve their required output at engine idle by being driven through the pulley system at up to twice their normal speed. Once the engine itself speeds up a clutch in the dual-drive unit is automatically closed and the pulley system reverts to direct drive. In this mode it has no mechanical losses as all the internal elements are locked giving, in effect, a solid pulley.
"The benefit of a two-speed drive is the efficiency gain by not running the alternator, water and air-conditioning pumps faster than is needed for effective operation," said programme director, Philippe Echardour. "The impact of this on vehicle fuel consumption depends on vehicle size, but independent studies have shown between 4% and 5% improvements. This is more than sufficient to justify the expected US$100 additional cost of a two-speed pulley. Further benefits will unfold as geared pulley systems are more widely adopted and when powertrain engineers start to design the front end accessory drive incorporating dual-drive units."
Antonov has similarly developed a stand-alone dual-speed alternator. This is targeted at a specific client application where insufficient current can be generated by the alternator at engine idle speed to meet the high demand from the vehicle. The vehicle currently has to have two alternators fitted which adds cost, package complexity and adds to losses at higher engine speeds. Antonov is now looking for other applications for this unit to assess if there is sufficient production demand to justify the development and tooling investment to take it to production.
The supercharger application, already in production for aftermarket applications, delivers better low end torque to an engine improving a vehicle's performance and driveability. The torque curve can be tuned so that a small displacement downsized engine can match the performance of a much larger naturally-aspirated engine.
Antonov has recently launched a self-contained, two-speed pulley unit, the Antonov dual pulley unit (DPU), to make available the benefits of dual speed drives to any belt driven application. The initial target market is US aftermarket supercharger installations where the relay pulley in the standard installation can be replaced by an Antonov DPU to provide two speed supercharger operations.
Three dual-speed supercharger studies are currently being pursued by Antonov. These include an engine downsizing application for a typical family car, an aftermarket application already in production for high performance vehicles and a performance enhancement application for off-road vehicles with relatively poor class performance, which is also in production.