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GETRAG to Exhibit Boosted Range Extender at METAV; Electric and Mechanical Drive

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The GETRAG Boosted Range Extender provides of all-electric or combined electric and mechanical drive. Click to enlarge.

The GETRAG Corporate Group will present its newly developed Boosted Range Extender at this year’s METAV, the international trade fair for manufacturing technology and automation, in Düsseldorf.

The Boosted Range Extender combines a two-cylinder combustion engine with an electric motor, alternator and power-shiftable two-speed transmission. When driving, the electric drive takes over the major portion of the dynamic driving conditions so that the internal combustion engine is only used for a small portion of the total characteristics map. Optimization of the system is therefore possible with regard to degree of efficiency, costs and installation space.

The electric motor provides continuous output of 30-45 kW, depending upon vehicle platform, with maximum output of 45-80 kW. Maximum drive torque is 220 N·m (162 lb-ft). The alternator provides continuous output of 10-20 kW (again, depending upon vehicle platform), with maximum drive torque of 30 N·m (22 lb-ft).

The transmission in the range extender. Click to enlarge.

The power shift transmission is actuated via a compact integrated control module/hydraulics unit. When starting off, the system is in electric mode in which the electric motor provides the propulsion in first gear. The increased wheel torque provides very good acceleration values and strong climbing power.

At a low state of charge for the energy storage system, the internal combustion engine starts and provides the energy supply via the alternator connected to it in serial operation. At typical speeds in city traffic, the combustion engine can then be directly coupled to the output in parallel operation.

Second gear is engaged outside the city limits. The internal combustion engine—if it is active—now runs in the range of the best possible specific consumption. In this driving mode, the electric motor takes over the dynamics where necessary.

The output is performed via a conventional bevel gear differential that was selected from GETRAG’s standard components catalog, just like a variety of other components. This design makes it possible to install standard components with a high production volume.

The total range—some 600 km (373 miles)—is comparable with one of a conventional vehicle, according to GETRAG. Compared to full hybrids, the Boosted Range Extender system packs in up to 60% less total drive performance (i.e. internal combustion engine, electric motor and alternator) with the same vehicle performance. The special torque characteristic ensures that none of the driving fun is lost.

The design of the Boosted Range Extender requires no revolutionary changes to the infrastructure and can go on the market for use with existing systems. So it should be possible to go for a fast market launch. It offers a solution that the market needs now and will be more than adequate to cope with tighter requirements in future. That has led to a great deal of interest in this product and we are currently in talks with a lot of interested potential customers.

—Rolf Najork, Executive Vice President for Research & Development

The Boosted Range Extender would be particularly useful for vehicles driven mainly within city limits, GETRAG suggests. A plug-in function also provides for charging from the power grid.

The Boosted Range Extender is part of GETRAG’s eDrive product line, which also include hybrid transmissions and electric drive units. GETRAG has also built battery electric and hybrid vehicle demonstrators.


Roger Pham

Perfect parallel hybrid design for HEV and PHEV. Just like what I have discussed here in GCC for the past several years (in response to the Volt's serial hybrid design)! Simple paralle hybrid design provides low cost with good performance. GM-Volt designers: take note!

Roger Pham

This is actually a serial-parallel hybrid design, with serial hybrid mode at low speeds and moving to parallel hybrid mode at higher vehicle speeds. A good way to overcome Toyota's patents on the HSD design.


Interesting, if a small ICE can provide most of the power for long distance cruising you can manage with a smaller and cheaper battery pack.

A 2 cylinder ICE @ 30kW with solid state thermoelectrics.
An electric motor @~100kW
~200Wh of supercaps with an output of around ~80kW
Enough Li-ions to go 20 miles ~6kWh


Interesting, but my engineering opinion is that the pure serial hybrid such as the GM Volt is an inherently better concept in that the engine is completely decoupled from the drive train. No clutches or transmission except for the final drive gearing are required. Most of the time, the engine would not run and when it does run, it can run in the best operating regime.


Time will tell which configuration PR manages to sell. The most simple series approach with best battery to genset power ratio could win but in the land where Hummer monsters sold, one could expect the unreal.


So many ways to improve the present, but no weight, cost, mileage, etc estimates.


"The power-shiftable two-speed transmission from GETRAG mechanically connects the internal combustion
engine with the electric motor when needed. The entire performance from the installed electric motor and
combustion engine can be used for propulsion."

(from the PDF on the link)

Roger and I must have been thinking along the same lines. Use the electric for take off and if needed combine the engine and motor for maximum horse power.

Nick Lyons

Nice building block. Seems like all the components are going to be available for ambitious integrators.


It is weird that they don't give any specifics on the ICE options. It must be compatible with a wide variety of options.

The 50g CO2/km quoted in the literature comes out to somewhere in the 100+ mpg (~2 L/100km) range, based on the estimated mpg from the Opel Flextreme post:

"Average gasoline fuel consumption is estimated at 1.6 L/100 km (147 mpg US), with CO2 emissions of less than 40 g/km."

No telling if that is based on a diesel, petrol, or other fuel engine, though.


I wonder what a small turbo diesel would do as a range extender. The engine has to be designed and built strong to withstand the internal pressures but the thermal efficiency is higher.

Henry Gibson

The OPOC is a good example of a diesel range extender. There is little reason to not have turbo supercharging on diesel engines. Actually a small tubine with a single moving part and air bearings is adequate. For efficiency reasons, most energy should come from the cahrging of a battery from cogeneration when the automobile is parked. But for now the costs of electric car motors and electronics needs to be reduced. ..HG..

Stan Peterson

Roger & sd,

In the debate over series-parallel or series drivetrains, my engineering opinion tends to side with sd, in the long run. The pure series approach with no compounding, offers the ability to optimize each specific component and its operating environments and thus optimize the entire drivetrain.

That I think, will prove superior, rather than making compromises to accommodate the reasonable needs of the operating environments of each and both prime movers, simultaneously.

It may prove true, that we have more experience with the ICE world than the battery mode, so today's choice may not be tomorrow's choice, as the electric drivetrain and its components improve.

That is what makes a horse race. And also two merit-able engineering designs.

I find it interesting that Getrag managed to create the '2-speed transmission' without apparent trouble, from available off-the shelf componentry, but that was beyond the capacity of Tesla's "engineering" staff, for almost three years, before they quit.

But I am reminded of the dictum "When the only tool you have is a hammer, every problem becomes a nail". Getrag is and was a transmission builder first, last, and always.

Roger Pham

Serial hybrid is good when you have a BEV with a small battery pack and want to be able to drop in a genset as removable range extender. Also, if you can make cheap electric motor and generator, and low-cost power electronics, then serial hybrid would be simpler to design and to maintain.

Serial-parallel hybrid is good when you want to keep the price of the vehicle low when the cost of electrical components are still high, and your prime objective is to build a HEV first, and a PHEV as an afterthought.

Time will tell.

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