just-auto interviews Herbert Negele, who oversees BMW’s hybrid-electric vehicle programmes.
At the Detroit Show last month, BMW showed two new hybrid-electric models: the ActiveHybrid 5 and the ActiveHybrid 3, based on the most recent sixth-generation 3-Series. The following is an extract from a full interview published in just-auto’s QUBE research platform.
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j-a: Your first-generation hybrid was the 2010 BMW ActiveHybrid 7, which paired a 15-kilowatt electric motor with the 4.4-liter twin-turbo V-8 engine. What distinguishes your two second-generation hybrids, which are models in the 5-Series and 3-Series ranges?
HN: They are a different concept. They are full hybrids, with the ability to run in all-electric mode, whereas the electric motor in the ActiveHybrid 7 only assisted the engine. They use an inline six-cylinder engine with an output of 225 kW (300 hp), and the electric motor is more powerful, with a peak power output of 40 kW (54 hp). The engine and motor combined have a maximum total power of 250 kW (335 hp). But like the earlier hybrid 7, both new cars use an adapted version of our standard eight-speed automatic transmission, with an electric pump to keep the pressure up when the engine switches off.
j-a: What was the development path of these cars?
HN: The system was originally designed for the 3-Series, our highest volume model. We decided we needed it for the 5-Series as well, but the hybrid team was able to work closely with the design team for the new 3-Series at an earlier stage of development. You will notice that in the ActiveHybrid 3, there is no compromise in trunk space despite the presence of the lithium-ion battery pack. That was the advantage.
j-a: How does the lithium-ion battery pack differ from that used in the hybrid 7-Series?
HN: The first-generation battery pack used cells from Johnson Control-Saft, whereas the new packs have A123 Systems cells. Both use cylindrical-format cells, but we felt that the JCI-Saft chemistry was somewhat safer. It was also easier to cool. And we like having competition among cell vendors too! For the second generation, the pack and its cooling system are a BMW design, built in Germany. We must build up our competence in battery technology.
j-a: What constrains the design of hybrids from BMW?
HN: Those cars are weighted more toward fuel efficiency, so we are better balanced in our lineup, including both cars for power and cars for efficiency. But they must still retain a sporty character. Our hybrid vehicles feel just like a normal vehicle, with no “hybrid” or “CVT” character.
j-a: Do the ActiveHybrid 5 and ActiveHybrid 3 offer different driving modes?
HN: Yes. Of course you can drive all electrically up to 60 km/h (36 mph). But the driver can also select among Normal, Sport, and Eco modes—that is something that will appear on all our models. Each mode provides a different mapping for throttle response and transmission shift points, and the Eco mode reduces the power provided for such things as air conditioning, heating, and even seat heaters.
The full interview is available to subscribers of QUBE mild-hybrids/full-hybrids intelligence services
It includes answers to questions:
Q: Do BMW’s new hybrids have unique technologies not found elsewhere in the hybrid field?
Q: Are the combustion engines completely beltless, with all auxiliary power provided electrically?
Q: Where are the hybrid models positioned in the 5-Series and 3-Series ranges, and what’s the launch schedule this year?
Q: Is BMW investigating plug-in versions of conventional hybrids, perhaps along the same technical lines as the Toyota Prius Plug-In or the “Energi” models of the Ford C-Max and Mondeo/Fusion?
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