A couple of hydrogen cars were available for journalists to test drive and review recently, namely the BMW Hydrogen 7 and a modified Toyota Prius. Wired News reviewed the BMW and brought up an interesting point about the vehicle’s cryogenic hydrogen storage system.
Because the liquid hydrogen is only super-insulated and not super-cooled, it will begin to boil off after only 17 hours of sitting and will be completely empty in 10 – 12 days. This means that leaving the BMW in an airport parking lot for a 2-week vacation would not be wise unless there was also some gasoline in the vehicle as well.
In another story, a Toyota Prius, modified to run on hydrogen by Quantum Technologies was open for test drives at the University of Buffalo in New York State. One of the trouble spots for this conversion is that on rainy days, “Water getting into the intake causes the engine to buck.”
Both the BMW Hydrogen 7 and the modified Toyota Prius use internal combustion engines (and not fuel cells), which burn hydrogen and power the vehicles. As more real world demonstrations and road tests are given, problems like these are sure to crop up and it will be interesting to see what solutions the engineers come up with to combat these issues in the months to come.