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Hybrids (pg. 5)
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| nchs09 |
| If someone really wanted to get the most MPG out of a car, they would get a diesel and not a hybrid. |
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| Moral Hazard |
| quote: | Originally posted by jennypie
The only people who drive Miatas are old, bald, aging, lonely men. Wearing baseball caps. |
AJ drives a Miata.... wait.... |
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| Silky Johnson |
| quote: | Originally posted by Moral Hazard
AJ drives a Miata.... wait.... |
Bahaha, see? |
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| kr00t0n |
| As long as there is money to be made from oil, viable alternatives will be kept under wraps. |
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| Omega_M |
| quote: | Originally posted by gehzumteufel
While I am not a fan of them in general, does anyone here think they are going about it in the totally wrong way? I believe the manner in which they are doing it to be quite inefficient. With all locomotives that are diesel-electric hybrids, the diesel motor does nothing with the actual work to move the train. That is all done via the electric motors. The diesel engine is strictly for electricity generation.
Now, I don't know how efficient it actually would be on such a small scale. Anyone else see things that I may not be in my quickly thrown together thoughts? |
You are wrong. Scale of engines is not the issue here. It's all about increasing the engine efficiency by always running it at its "sweet spot". Internal Combustion Engines give a maximum efficiency of 40%. And this is only at a certain point on the Torque-Speed curve (sweet spot). The hybrid architecture ensure that the vehicle runs at this point always, thereby increasing average efficiency to around 40% which otherwise is generally around 30% or less. The other interesting feature of hybrids is that they recover energy when the vehicle brakes. This is called brake energy regeneration.
Now lets go a bit deeper into the architectures of the hybrids. Very broadly there are two types, the Series Hybrid and the Parallel Hybrids.
A parallel hybrid is a slightly less complex system. The engine is connected to the wheels of the vehicle through a conventional transmission. A parallel battery / motor system stores energy when the vehicle brakes. There is an arrangement wherein this battery driven motor can assist the engine to rotate the drive shaft thereby reducing load on then engine = fuel savings. This type of architecture gives approximately 30% improvement in fuel efficiency in trucks.
A Series Hybrid on the other hand is a slightly more complicated architecture, but gives much higher fuel efficiency (over 70% for trucks). The engine is decoupled from the wheel. It only drives a motor that charges a battery. The battery pack drives wheel motors which move the vehicle. There is no conventional transmission. So there's no direct coupling between engine and wheels. The controller ensures that the engine always runs at its sweet spot and shuts off when not needed (when battery is charged). Brake energy regeneration adds to the improvement in fuel efficiency.
Batteries have an inherent disadvantage. They typically have low power density. Meaning you cannot get large power output due to the limitations on the battery discharge rates. Hydraulic systems can provide high power density. So people are already developing hydraulic hybrids for trucks (Class 8, Class 6). At the moment, this technology can give fuel improvement only in large and heavy vehicles. And those too, which make frequent starts and stops (eg. Garbage pickups, Courier delivery vans etc). But they are also working on putting this technology into small cars. Do a search on "hydraulic hybrid" for more information. |
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| dj_alfi |
| quote: | Originally posted by DuBam
Hybrid? Like hash & marijuana rolled together?
I like :) |
perkele, i think i love you. |
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| gehzumteufel |
Ahh I wasn't aware that the Karma was using what I was referring to! SICK!!!!
| quote: | Originally posted by david.michael
Clean diesel ftw.
Planning on getting an 09 Jetta TDI here in about 2 months. |
+1 on diesel. I am hoping for a diesel (if it happens, a VW GTD) to be my next car.
| quote: | Originally posted by Omega_M
You are wrong. Scale of engines is not the issue here. It's all about increasing the engine efficiency by always running it at its "sweet spot". Internal Combustion Engines give a maximum efficiency of 40%. And this is only at a certain point on the Torque-Speed curve (sweet spot). The hybrid architecture ensure that the vehicle runs at this point always, thereby increasing average efficiency to around 40% which otherwise is generally around 30% or less. The other interesting feature of hybrids is that they recover energy when the vehicle brakes. This is called brake energy regeneration.
Now lets go a bit deeper into the architectures of the hybrids. Very broadly there are two types, the Series Hybrid and the Parallel Hybrids.
A parallel hybrid is a slightly less complex system. The engine is connected to the wheels of the vehicle through a conventional transmission. A parallel battery / motor system stores energy when the vehicle brakes. There is an arrangement wherein this battery driven motor can assist the engine to rotate the drive shaft thereby reducing load on then engine = fuel savings. This type of architecture gives approximately 30% improvement in fuel efficiency in trucks.
A Series Hybrid on the other hand is a slightly more complicated architecture, but gives much higher fuel efficiency (over 70% for trucks). The engine is decoupled from the wheel. It only drives a motor that charges a battery. The battery pack drives wheel motors which move the vehicle. There is no conventional transmission. So there's no direct coupling between engine and wheels. The controller ensures that the engine always runs at its sweet spot and shuts off when not needed (when battery is charged). Brake energy regeneration adds to the improvement in fuel efficiency.
Batteries have an inherent disadvantage. They typically have low power density. Meaning you cannot get large power output due to the limitations on the battery discharge rates. Hydraulic systems can provide high power density. So people are already developing hydraulic hybrids for trucks (Class 8, Class 6). At the moment, this technology can give fuel improvement only in large and heavy vehicles. And those too, which make frequent starts and stops (eg. Garbage pickups, Courier delivery vans etc). But they are also working on putting this technology into small cars. Do a search on "hydraulic hybrid" for more information. |
I was not aware of the proper term, but the hybrids I was hating on were the parallel hybrids, and the ones I was referring to that locomotives use is the series hybrids. I was saying that the hybrid in the prius, the parallel, is horrible as compared to the series hybrids. |
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| miamitranceman |
Fuel Cell/Hydrogen seems the most promising down the road. It will take some years, but it runs completely clean and its source, for all intents and purposes is endless.
With technology like that they can still produce fantastic gas/diesel sports cars for the rest of us! :toothless |
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| gehzumteufel |
| quote: | Originally posted by miamitranceman
Fuel Cell/Hydrogen seems the most promising down the road. It will take some years, but it runs completely clean and its source, for all intents and purposes is endless.
With technology like that they can still produce fantastic gas/diesel sports cars for the rest of us! :toothless |
Hydrogen uses a lot of energy in the extraction though. |
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| infinity HiGH |
| All you diesel fans, just an FYI that Audi is bringing over their A3 TDI by years end over to this side of the Atlantic. |
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| noikeee |
| quote: | Originally posted by d-miurge
It's out already. There are some "air-taxis" in Mexico City. |
Great, new innovative ways of getting the swine flu. |
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| david.michael |
| quote: | Originally posted by noikeee
Great, new innovative ways of getting the swine flu. |
:stongue: |
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