When most people think of Getrag, visions of transmissions commonly pop into mind. However, with vehicle electrification increasingly becoming a reality, the transmission business will inevitably change and Getrag wants to be prepared. Thus, the German company is starting to promote a range extender system comprising a small engine, electric motor and a two-speed gearbox.
The full package is designed to run mostly as a series hybrid with primary electric drive and the engine starting only when the battery gets low. If needed, the engine can also drive the wheels directly in a parallel hybrid mode. The specs call for a motor of 30-45 kilowatts. No specifications are given for the engine but, from the illustrations, it is clearly a two cylinder of unknown origin. A 10-20 kW belt driven alternator on the engine is used to charge the battery. Overall, this system would be suitable for a small urban commuter car. No automaker has yet given an indication that it plans to use the Getrag system. The press release is after the jump.
Boosted Range Extender 2RET300
Cost-effective, efficient and already suitable for everyday Use: The Boosted Range Extender
With the Boosted Range Extender, GETRAG has developed a cost-effective electric drivetrain architecture
that unites and outperforms the advantages of conventional drives, hybrid drives and the currently available pure electric drives. By combining an internal combustion engine with an electric motor, outstanding performance data can be achieved despite the CO2 and fuel consumption optimized design. When driving, the electric motor usually takes over the task of driving the vehicle. With a low charge status, the internal combustion engine charges the battery. On long stretches, the vehicle can also be driven directly by the internal combustion engine or by both machines. The total range is comparable with one of a conventional vehicle. The design of the boosted range extender does not require a revolution in the infrastructure. It is marketable with the existing systems. This enables prompt market introduction.
The selected combination of a modern internal combustion engine capable of burning multiple fuels and an electric motor with a power-shiftable two-speed manual transmission allows efficient operation in every operating point. Thanks to the very low CO2 emissions of less than 50 g CO2/km (NEDC), this design also fulfills the more stringent requirements of future legislation. Compared to the full hybrids, up to 60 % less total drive performance (internal combustion engine, electric motor and alternator) is installed with the same vehicle performances. The special torque characteristic of the electric motor enables more driving pleasure compared to conventional drives. The pure electric mode is primarily intended for city traffic, which results in a considerable reduction of noise and emissions in metropolitan areas. It can also be used on country roads or highways, however.
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. In addition the available ratios allow a cost and need-oriented design of the electric machines (motor and alternator) and the internal combustion engine.
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. A clearly focused optimization of the system is therefore possible with regard to degree of efficiency, costs and installation space. 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. Thanks to the increased wheel torque, very good acceleration values and an outstanding climbing power are achieved. At a low charge status of the electric storage unit the internal combustion engine is started 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 status, 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.
planetary gear set power shift
Number of gears: 2
Lubrication: internal 1-chamber lubrication, no external cooling
Maximum driving torque: 3,500 Nm
Maximum width: 516 mm
Installation length: 390 mm (with electric motor)
Installation height: 536 mm (with electric motor)
Weight: approx. 55 kg (without electric motor)
Continuous output (@UHB): 30 kW – 45 kW (depending on vehicle platform)
Maximum output (@300 V): 45 kW – 80 kW (depending on vehicle platform)
Cooling design: water-cooled
Maximum drive torque: 220 Nm
Maximum drive speed: 12,000 rpm
Continuous output (@UHB):
10 kW – 20 kW (depending on vehicle platform)
Cooling design: water-cooled
Maximum drive torque: 30 Nm
Maximum drive speed: 15,000 rpm
The GETRAG Corporate Group is the largest independent passenger car transmission manufacturer in the world with around 13,450 associates at 24 sites. The company is headquartered in Untergruppenbach, Germany. The group develops technical solutions for the automotive industry and has a broad product range of transmission systems and drivetrain components for passenger cars, SUVs, motorcycles and light commercial vehicles. The group achieved sales of € 2.5 billion in 2008.