Of course, conventional full hybrids offer the same capabilities, but they typically use very high-voltage electrical architectures and high-voltage batteries. A few years ago, the Toyota Prius used a 500V electrical architecture, while the Ford Escape Hybrid employed a 330V system, and a Lexus hybrid SUV operated at more than 600V. Those voltages enable hybrids to support up 20kW of electrical loads, compared with about 1.5kW on conventional 12V gas-burning cars. As a result, they have an easier time handling extra electrical features, such as heated front seats, heated windshields, rear defrosters, and eventually electric air conditioners, active chassis, and drive-by-wire systems.
Still, the 48V architectures will offer significantly more power than conventional 12V systems using lead-acid batteries, even if they don't reach the level of a Prius. "You have the potential to boost the power levels to 10, 11, and even 12kW," Rigby said. "It's not as much as a [full] hybrid, but it's certainly not insignificant."
Suppliers see the 48V architecture as a sort of addendum to start-stop technology, but it's a big addendum. A 12V start-stop may boost fuel efficiency by 5 percent, but a 48V start-stop would offer a 15 percent advantage.
If start-stop's uptake rate is an indication, 48V has a chance for big adoption. In Europe, approximately 50 percent of the cars produced this year will be start-stop vehicles, and that figure is still rising. Rigby said 48V could offer the same kind of consumer appeal. "It's going to come down to the economics. How much will it cost? What's the payback? What's the price of fuel? Those things will determine how fast it gets adopted."
:-) I agree, and it's not always the best ideas that make it, only the ones that capture the imagination of the buyer/are better marketed (to a point). As a funny life experience with start/stop technology, in 1972 I had the clutch cable break on my 1965 beetle while waiting to drive on a ferry. I turned off the ignition, put it in reverse and turned the key then did the same in forward/reverse/forward again doing a 3 point turn and then proceeded to drive to a workshop by the same means. Once in first I could change gears by revving just the right amount AND THAT WAS A 6 VOLT SYSTEM :-)
but i do agree, even though every actual start/stop car I've driven this year has been a 12V system, charge recovery has to be better with higher voltages.
Someone will have to figure out at what fuel price point the expense of 48V etc. is justified.
If I may ramble on, I have often wondered about start/stop from an emissions and consumption standpoint, because a partially warmed engine uses about 20-30% more fuel, has significantly higher engine wear, and emissions are more difficult to control during warm up as well. This is partially because of catalytic converter temperatures. I know they can electrically heat them, but that's more fuel too, so I would be interested in knowing how much benefit there is if you're not stuck at a level train crossing for 10 minutes. I'm not saying stop/start isn't a good idea, only asking is it? and how good?
As you point out, there are a lot of very good reasons to question the viability of this idea, etmax. The one big thing it has going for it, though, is the inevitability of start-stop technology. Higher voltages are better for the operation of the starter-generator. And 48V lithium-ion is better at capturing that regen energy. As you say, it will be interesting to see (and if) this pans out.
Hi Charles, I often wondered why a technology (42V) that even Delco was touting as being the next big thing died, but at the end of the day it did add a lot of unnecessary cost at the time. Now 48V and a lithium battery it seems an even greater cost is being introduced, and given the deadly combination of a lithium battery and lots of falmmable plastics and fuel I thing the battery will have to be armour plated and placed within the confines of the passenger safety cell to avoid a catastrophe in an accident. Another show stopper I see is the LV directive that cuts out at 42V (possibly one of the reasons why 42V was chosen) so it will be interesting to see how it pans out. I don't think I'm going to hold my breath, as to me it looks like another attempt to sell a new idea for not too much added value. I've don't measurements on my car and the A/C uses very little, something around 1-2%
I don't think you can blame unemployment on current fuel prices, the US has very low fuel prices (based on global levels) yet has much higher unemployment. If anything that would indicate that high fuel prices lower unemployment. Of course that isn't the case either. What it is are 2 things, first there are not enough people earning enough money to be able to spend it in the wider economy therefore the economy is sluggish. If some of the money that is in the hands of the super rich and is spent on enormous mansions and $1000 handbags were distributed to the 30% of the population that can only afford to eat and shelter things would look better
The lithium ion battery technique will enable for the recapture of battery energy as it has been put by Charles. The use 48 V in the locomotives will no doubt lead to a cheaper and efficient method of locomotion. The answer to 48 V is therefore definitely a yes.
The question of whether engineers could have foreseen the shortcut maintenance procedures that led to the crash of American Airlines Flight 191 in 1979 will probably linger for as long as there is an engineering profession.
More than 35 years later, the post-mortem on one of the countryís worst engineering disasters appears to be simple. A contractor asked for a change in an original design. The change was approved by engineers, later resulting in a mammoth structural collapse that killed 114 people and injured 216 more.
If youíre an embedded systems engineer whose analog capabilities are getting a little bit rusty, then youíll want to take note of an upcoming Design News Continuing Education Center class, ďAnalog Design for the Digital World,Ē running Monday, Nov. 17 through Friday, Nov. 21.
Focus on Fundamentals consists of 45-minute on-line classes that cover a host of technologies. You learn without leaving the comfort of your desk. All classes are taught by subject-matter experts and all are archived. So if you can't attend live, attend at your convenience.