Edmunds.com interviews BMW’s Professor Raymond Freymann, the managing director of BMW Group Research and Technology. An aeronautical engineer by training, he has been at BMW for almost 20 years.
As the company has often said, BMW is bullish on hydrogen long-term, although not necessarily on fuel cells. Hence their emphasis on internal combustion engines fueled by hydrogen. BMW will be offering a bi-fueled (H2 and gasoline) 7 Series within two years—earlier post).
We think the future is not so radical. All of our consideration is on internal combustion engines. We’re not sure fuel cells will happen—other than as the power source for everything driven electronically, such as air conditioning, in-car entertainment, lights, etc. For this application, the fuel cell makes perfect sense. But as the power source for driving the car? That is a huge step.
Rather, we think the internal combustion engine, fuelled by liquid hydrogen is perfect. The technology exists. The internal combustion engine also offers much better power density and efficiency than fuel cells. Fuel cells have such a long way to go. I'm not sure anyone would be able to pay the bills.
Hydrogen will work best in direct-injection engines with supercharging. The thermal efficiency of a hydrogen internal combustion engine will be more than 50 percent. Gasoline engines currently operate below 40 percent and diesels just above 40 percent. The hydrogen engine will have more power and more torque. And no pollution. Initially, maybe we will make [hydrogen] from natural gas, but eventually all hydrogen will be produced using renewable energy—such as solar power.
Freymann predicts a peaking of diesel popularity in Europe as direct-injection gasoline engines gain greater presence. And he is somewhat dismissive of current hybrid designs (“two engines...simply add weight to the car, and add money to the car”).
Freymann indicated that BMW is working on a gasoline-electric hybrid, however, but using supercapacitors boosted by regenerative braking, rather than batteries.
[The super capacitors] are lighter and store less power, but unlike batteries we can use all their power—all 100 percent. An electric engine has a lot of torque at low revs—that is its main benefit—so it’s ideal for fast initial acceleration. At higher revs, once you’ve begun to accelerate, nothing can beat an internal combustion engine. Our hybrid approach combines the best characteristics of both engines.
BMW has worked on ISAD (Integrated Starter Alternator Damper)-like hybrid systems for a number of years, as chronicled in the IEA Implementing Agreement for Hybrid and Electric Vehicle Technologies and Programmes Overview Report 2000.
IEA Hybrid and Electric Vehicle Implementing Agreement website