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New Semiconductor Could Improve Vehicle Fuel Economy By 10 Percent
cartechboy writes: "Automakers are scrambling to increase vehicle fuel economy every year as regulations increase, so when an automaker finds a way to possibly increase fuel economy by 10 percent with one new part, that gets some attention. Today that automaker is Toyota, and the part is a new semiconductor. Toyota's power control units (PCU) in its hybrids use semiconductors to govern the flow of electricity between the battery and the electric motor. Unfortunately, they're also an electrically restrictive component. Toyota says the PCU accounts for a quarter of the total electrical power losses in a hybrid drive system, and semiconductors alone make up a full fifth of the total. Reduce electrical losses through a semiconductor, and you can make your hybrid system (and therefore your car) more efficient. Toyota has done this, in theory at least, using a new silicon carbide material for its semiconductors, rather than a standard silicon unit. The future could be shaped by individual parts, and this new semiconductor tech is one piece of that puzzle."
Are these SiCFETS with lower R(on), or improved SiC IGBTs, or what?
I wouldn't think so, because silicon carbide transistors isn't brand spanking new, unless you count a few years old as new.
The summary makes it sound more like electricity economy.
The article isn't any better. It is so badly written that I can't really tell what they are trying to say. I think they have reduced electrical losses by 10%, which is totally different from increasing efficiency by 10%. I believe that most electric vehicles are already over 90% efficient, so increasing that by 10% would be almost impossible.
How is this news? SiC semiconductors including Schottky diodes, JFETs and MOSFETs have been commercially available since 2008. My first design to use SiC JFETs and diodes was in solar power inverter developed back in 2009 (and yes the RDSon and revers recovery times are indeed exceptional). Stay tuned for: "Toyota discovers wonder metal by adding carbon to iron"
Buses take longer. There's only so much time per day, if you spend it waiting for buses, you get less done.
[foxworthy] /.er
If you have a favorite local semiconductor manufacturer, you might be a
[/foxworthy]
"Never let your sense of morals prevent you from doing what is right" - Salvor Hardin
10%+ increase in efficiency gets automakers' attention? No it doesn't.
If they were really serious about fuel economy, they'd go to work on the aerdynamics for starters. Current vehicles have far too much air resistance. And actually they know this. They don't improve the aerodynamics for several reasons. They're afraid the public will think it ugly, and they think it will cost more to manufacture. One of the simplest improvements are skirts for the rear wheels. Every time it's been tried, the public rejects it. Another easy improvement is smoothing the underside. But that costs more, and not just during manufacturing. It also increases maintenance costs as it's one more item that has to be removed to service much of the car.
Intellectual Property is a monopolistic, selfish, and defective concept. It is "tyranny over the mind of man"
You have to factor in time, as well. I *do* walk and take public transportation, when the combination of effort, time and money one of those options costs seems nicer than driving - for instance, driving into downtown LA, is a lot faster than taking the light rail if there isn't traffic, but there's usually traffic, plus then when you get there you have the immense fun of finding parking. So it's often (not always) nicer taking the train, so I do. On the other hand, I tried taking the bus once across town. It's pretty cheap, but it takes bloody forever, so it's unlikely I'll ever try that particular experiment again, given that taking a car across town is far more convenient. If public transportation were more convenient, I imagine people would use it more. (That's not particularly insightful, though; seems pretty obvious, really.)
The problem with diesel cars in the USA is that they're more expensive than current hybrids (particularly the Prius) and diesel fuel is on average more expensive at the pump than 87 octane gasoline.
It has a faster recovery time too. More MOSFET's won't change that.
Faster recovery time means they can run at a higher frequency and use smaller inductors to convert the voltage. Lower inductance means less copper, less resistance. So not only is there less loss in the transistor, there is less loss in other components.
If you keep adding more MOSFET's, you need to keep increasing the drive current or they'll switch slower.
While a MOSFET is switching, the resistance can be quite high. Even if faster silicon carbide transistors had the same Rds, there would be lower losses during switching.
Yep. Unlike aircraft, there just isn't a significant desire by the auto manufacturers to really get serious about drag reduction. It's really a shame too since things like wheel skirts are really simple.
I think part of the problem is that they intentionally put them on the most unconventional looking cars just to help ensure they don't sell because people are hesitant to significant change. I'd rather they step up and tell people how much fuel that would save with them on and what that would cost annually. And have it as a package you can put on at the dealership.
I prefer mp4...
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Diesel cars have much better mileage, more torque and diesel engines normally last longer than regular cars.
but I agree hybrids are better for city use.
I've got better things to do tonight than die.
Tesla claims an overall efficiency of 88% for their cars, from grid to wheels.
This is pretty interesting, but it's not clear exactly what that 88% represents. I'm not sure what "overall drive efficiency" is. They put a picture above the 88% figure that has elements that probably aren't in the "drive efficiency" number -- misleading at best. It probably doesn't count the grid->battery efficiency (why else would they include the word "drive"?)
I'm waiting for someone to make the Mythbuster's Dimpled Car. They got nearly 10% better MPG in their test.
Looks like Toyota has produced the pinch-channel Class I V transistor in SiC with no minimum offset / gain.
Seriously, holy grail for current steering.
Can't find the vendor of the raw SiC so no idea about Delta-V / Delta-I limits but looks very good
10% net reduction in loss.