'Efficient Dynamics' is
the declared goal of the BMW Group's drivetrain development division.
" This resolves the apparent conflict between reducing consumption
and emissions on the one hand and enhancing performance and agility
on the other," commented Professor Burkhard Göschel at
the Vienna Motor Symposium. It means that the requirements for environmental
compatibility and consumption are not viewed in isolation but in
the context of the close interplay between statutory requirements,
social acceptance and customer demands.
"An important component in developing drive technology
lies in intelligent electric power for the drive, for example through
an 'active gear', combined with high-performance capacitors. Developing
a hybrid vehicle that drives for long distances on electric power
is not commercially viable over the long term and is therefore not
goal-oriented.
Not everything that is technically feasible is also economical and
ecological. And, most importantly, it doesn't necessarily convince
the customer. An intelligent drive where power can be called up
at any time and which provides more spontaneity for less consumption
is a realistic development proposition," emphasises Professor
Göschel.
Option for the future: 'Efficient Dynamics' with electrified drivetrain
BMW has already played through an extreme initiative. An electric
motor integrated into a BMW X5 experimental vehicle between the
internal combustion engine and the gearbox supports the conventional
drive during acceleration. The research vehicle was launched in
2003 and produced responses that had never been attained before,
while also increasing torque to 1000 Nm in the lower range. On the
other hand, the vehicle also reduced consumption by up to 15 per
cent in the driving cycle.
Looking into the future, Professor Göschel can imagine a compact
'active gear' that integrates the electric motor and the power electronics
in a single assembly within the gearbox. This will significantly
reduce the additional weight and the construction space required
for the system. High-power capacitors, elegantly stowed in the door
sill, could contribute to an additional benefit. By comparison with
battery systems, capacitors have significantly higher charge and
discharge rates over the short term. As Professor Göschel sees
it, the function of an intelligently honed drive is to intervene
electrically in the drivetrain and optimise driving situations like
stop-and-go traffic or acceleration.
Long-term development potential is with the internal combustion
engine
However, all concepts geared towards intelligent electrification
remain no more than an auxiliary solution for the internal combustion
engine. BMW has significantly reduced consumption and emissions
in diesel engines during recent years, while simultaneously increasing
performance and torque. Valvetronic, the fully variable valve control
system, has allowed BMW to achieve comparable improvements in the
petrol engine. In future, the introduction of spray-guided direct
injection and the implementation of lean combustion will bring consumption
in the petrol engine closer to values attained by modern diesel
units.
Over the long term, hydrogen is still reckoned to be the fuel with
the greatest potential for safeguarding mobility in the future.
BMW specialists are working on the hydrogen combustion engine, where
an overall efficiency of up to 50 per cent is conceivable in the
long run.
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