Powertrain 2020 - The Future Drives Electric (PDF ... - Roland Berger

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The new versions will most likely be PHEVs based on a parallel hybrid
powertrain layout that can utilize the body and crash structures as well as
the gearbox and axles of conventional ICE-powered models.
In terms of packaging, integrating a PHEV powertrain into a large vehicle
with a longitudinally placed engine should not be a problem. The electric
motors and power electronics are only marginally larger than their conventional
equivalents and will fit into the existing parallel hybrid powertrain.
The medium-sized battery will probably fit into the trunk area.
This is not the case with smaller, mid-size vehicles with transversely
mounted engines. For these vehicles, designing a PHEV version with a
parallel hybrid system will involve major packaging problems. Serial hybrid,
mixed parallel-serial hybrid and pure EV layouts will most likely be the
preferred solution. Doing without the multi-stage gearbox will save on
some of the limited packaging space.
A dedicated vehicle platform will probably be designed first for pure EVs
in the smaller car segments, where there are higher volumes and greater
customer acceptance for pure electric driving. A good example is Renault's
new "City EV", to be launched in 2012.
2.2.3 Key powertrain components
For pure electric driving, the powertrain consists of just three major components:
an electric motor (possibly with a multi-gear transmission), power
electronics, and an energy storage system. Complexity increases if a range
extender system is added.
2.2.3.1 Electric motors
Electric motors have a completely different torque characteristic to that
of ICEs. They reach their maximum torque at very low motor speeds. By
contrast, ICEs usually need at least one-third of their maximum engine
speed to reach peak torque. The Tesla Roadster is a good example of the
additional driving pleasure that this creates for end customers – a pleasure
that will probably be available not only in high-performance cars, but in all
vehicle segments.