Regenerative Braking
Regenerative Braking
(OP)
I have a request from a car manufacturer to include the 'regerative braking' function in an ECU but I do not know what electronics is to be included.
Is just software?
Is just software?
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RE: Regenerative Braking
Cheers
Greg Locock
RE: Regenerative Braking
Northrop used electric motors to drive/brake their "Swords to Plowshares" bus boondoggle. I was stuck with doing the software and simulation of the energy system. Braking was by using the motors as generators with the power going into batteries (which is only 50% efficient) and the excess into heating elements. The batteries were dumped as it took more power to haul them uphill than recovered going down. So it ended up being a natural gas powered electrically driven bus.
RE: Regenerative Braking
RE: Regenerative Braking
Regards
pat pprimmer@acay.com.au
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RE: Regenerative Braking
Electric vehicle retarders used in trucks busses, and trailer axles have pairs of massive (50Kg or more) steel flywheels with fan blades built into them where the downhill energy is dumped as eddy currents. They glow red hot when in maximum usage.
If you are going to get any effective braking, regen or otherwise, since we all agree that charging batteries is not a very good way to go, wasting the energy in a similar fashion after you have stored all you possibly can is the only option.
What about charging up diodes?? (easy to ask, since I am not an electrical engineer)
rmw
RE: Regenerative Braking
Of course, in order to be lightweight, it has to turn fast enough to put the blades at a high sress level, and when you do that, it becomes a single speed device, which doesn't match a truck application very well. I don't think he had researched the subject enough to learn about compressor stall, where the power requirement suddenly falls off, and because of the subsequent overspeed, the maximally stressed blades fall off too.
Uh, diodes don't store anything, so you can't charge them up. You can charge capacitors, but the energy density doesn't approach that of batteries.
The whole concept of 'charging' something for regenerative braking implies the existence of a device that doesn't actually exist; a high power level Continuously Variable Transmission, that can accept power from a decelerating low speed drive, and transfer it with minimal waste to an accelerating or constant speed high speed drive.
Mike Halloran
NOT speaking for
DeAngelo Marine Exhaust Inc.
Ft. Lauderdale, FL, USA
RE: Regenerative Braking
I have heard nothing from this effort since 2003 when I saw a small article on the bicycle with referance to the DeLorean. Other than that, nothing!
Rod
RE: Regenerative Braking
When braking, the electrical engine is the main brake, and only at lower speeds these vehicles use classical friction brakes. When braking, the electrical engine becomes generator and pumps current up into the electrical network. Only there is one problem: there should be in the neighbouring area an other vehicle, which is accelerating right at that time, then you have a user, which will use the power pumped into the network, by the braking vehicle. If there is nobody to use that current, every vehicle has braking resistors, and the generated current is routed there, and all the current will go out on the resistors into the air as heat, and will be lost.
That's why in some European cities they interconnect the tramcar and trolleybus current network, this way doubling the possibility of beeing somebody around already accelerating, when somebody else is braking.
This kind of equipment manufacturers are Kiepe, Ganz Transelektric, Siemens, IKPE SAERP and I belive Bombardier also has this kind of equipment. You can try their websites for further info.
By!
RE: Regenerative Braking
If the flywheel is used for regenerative braking only, and not as the prime mover, the size can be kept quite reasonable and can be made of 4340.
I have a prototype IVT system in my basement that I designed and built about five years ago. The problem as you stated is sizing up the torque capability, not impossible for one of the big three but certainly way beyond my means.
RE: Regenerative Braking
Could the same system also recover power ?
RE: Regenerative Braking
Cheers
Greg Locock
RE: Regenerative Braking
Back in the late seventies, somebody put one of these systems in a Granada. The engine was set up to pump up the accumulator, and the drive was hydraulic only. Doubled the fuel economy when driven side by side with a conventional Granada. I think I still have the Popular Mechanics or Science article somewhere.
I had heard that Ford was implementing this on the F-350 as a power aid. Has seventeen years passed already?
RE: Regenerative Braking
Nobody was interested.
".. got fuel to burn, got roads to drive.
Keep on rockin' in the free world." - NY
RE: Regenerative Braking
I suppose cost and complexity, and the unusual layout would discourage many car manufacturers from taking up something like this. I am not surprised that the hydraulic idea has already been tried. When gasoline is ten dollars a gallon some of these ideas might be looked at again with more interest.
Unless there is a major breakthrough with battery technology (unlikely) hydraulics may hold more promise. At least the hydraulic accumulator will not slowly die and need frequent replacement every few years like batteries.
RE: Regenerative Braking
I worked on the Northrop electric hybrid bus. Driven by electric for political reasons. Excuse for eliminatating hydraulics from the drive source was due to preceived mechanics inability to service hydraulics without it leaking.
Scrapped regenerative electric braking due to poor charge/discharge efficiency of batteries and penalty of carrying dead weight uphill. So braking energy was all dumped as heat in cooking elements. Of course none of it used to heat the cabin. That came from a 35,000 RPM 120db aircraft APU from Israel (read boondoggle trip). The positive note was the boom boxes were overwhelmed by the electrical noise of all the electrics.
Car manufacturers are entrenched in petrol engines and will not consider alternatives until public pressure demands it.
RE: Regenerative Braking
I guess i always considered hydraulic systems to be relatively heavy. Has anyone got a link or drawing as to how the system would work? Finding it a little difficult to visualise how an 18hp engine can drive a car efficiently and still have good accel etc.
RE: Regenerative Braking
Regards
pat pprimmer@acay.com.au
eng-tips, by professional engineers for professional engineers
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Regenerative Braking
The 18 HP fuel motor was just to recharge the accumulator as needed. The variable displacement hydraulic motor drove the standard VW transaxle. The "gas" pedal varied the drive motor displacement which had 3000 PSI feeding it. At top speed the fuel motor is providing all the hydraulic fluid to the drive motor and none is going into the accumulator.
If you think hydraulics are heavy, think again. They are commonly used in aircraft to move the control surfaces. If there was a lighter method it would have been used in commercial aircraft that are highly dependent upon light weight for cost savings. Military systems are going to 5000 PSI. A leak in that would cut your fingers off.
RE: Regenerative Braking
Hydraulics are the only practical (and cost effective method) currently available for capturing a significant portion of braking energy in an automotive application.
Ford/Eaton are working to bring a system to market for cars and light trucks:
http://h
Permo-Drive has a system for heavy vehicles:
http://www.permodrive.com/
Regards,
Terry
RE: Regenerative Braking
Lots of strange, amazing vehicles!
Electric vehicles, gas/electric hybrids, gas/hydraulic hybrids, one hydrogen-fueled car.
Many vehicles were incomplete (like ours, from Cal Poly Pomona), but a fair number went through the emissions dyno test, the test track loop, etc.
We watched some kind of Dodge or Plymouth whine/howl its way aroud the track- I think it had a small Diesel with hydraulic drive...
Anyone here remember the event?
Jay
Jay Maechtlen
RE: Regenerative Braking
I believe Ford is no longer working with Eaton on their system. FEV showed a series hybrid hydraulic concept on a Ford Expedition vehicle last year. Permo-Drive is working with Dana to commercialize their system for medium and heavy vehicles. Both the Permo-Drive and Eaton Systems are parallel hybrid and could be considered Hydraulic Launch Assist (HLA) as they are not used at higher speeds.
Best regards,
Matthew Ian Loew
Please see FAQ731-376 for tips on how to make the best use of Eng-Tips Fora.
RE: Regenerative Braking
RE: Regenerative Braking
RE: Regenerative Braking
RE: Regenerative Braking
http://www.epa.gov/otaq/technology/420f05006.htm