Talk:Regenerative braking

NYC
> New York City subways are about to see this installed.


 * What is meant with "this" - 'regenerative braking' or 'large banks of resistors' ? 213.51.209.230 13:32, 21 Aug 2004 (UTC)

Relation with hybrid
Among confusions about the hybrid cars, many seem to believe that hybrid is mainly to allows regenerative breaking ? It is not. Hybrid is one way to avoid the lost of efficiency of powerful piston gas engine when running at low power, the Quasiturbine photo-detonation engine being one other possibility. Regenerative braking energy recovery is insignificant on the highway, little when the battery are near fully charge, limited to soft breaking (heavy breaking exceeding recovery power capability), and none for now from the back wheels (still waste energy to standard friction brakes) http://www.hybridcars.com/renerative-braking.html. It is however valuable in intense city driving, and is also of course an asset of most hybrid concepts. Regenerative braking system can also exist independanty from hybrid. City driving car energy use is shown at : http://www.fueleconomy.gov/feg/atv.shtml Gilles


 * I would have thought that was obvious.. ? But regenerative breaks are easier (cheaper) to impliment in vehicals that are normally driven from a source of electricity (rather than gasoline or something) - IE hybrids or electric cars. Of course, if one made the ability for a gasoline car to be run by a battery then it could use regenerative brakes - but it would become a hybrid in the process. Regenerative brakes could be used to charge a car's battery (which isn't used for propulsion), as the braking energy is simply energy that can be used anywhere. Maybe note of this needs to be made in the article. Fresheneesz 20:00, 30 May 2006 (UTC)

a couple of train related questions
1: i was under the impression that rehostatic breaking rather than friction breaking was used if there was nowhere to put the regenerated power. 2: i presume deisel electrics still generally rely on rehostatic breaking (though i've heared a few are now using batteries) is this correct?


 * Primary train brakes are almost universally air brakes (occasionally electropneumatic). These are of course friction brakes.
 * Locomotives universally (except for very early on) have friction brakes on their wheels. Normally straight air brakes, although steam brakes were often used on steam locomotives.  N.B. The term for locomotive brakes is "independent brake" (said brakes can be controlled independently of the automatic or train brakes). BDD
 * The vast majority of electric and diesel-electric locomotives have rheostatic braking available as well. (this is "dynamic braking" in US railroad parlance). Railroaders like this because it does not wear or heat up the friction brakes, and applying more braking from the locomotive causes the train's slack to bunch up, allowing for an easier time once a rise is encountered again.
 * A small number of electric locomotives have regenerative braking. This generally requires direct current electrification; alternating-current regenerative braking requires the locomotive's generation to be 'in phase' with the supply.

Hope that helps. Matthew Brown (Morven) (T:C) 23:23, 7 May 2006 (UTC)

dynamic brakes
Dynamic brakes should probably get their own section, since theres significant discussion about them - and as of right now, the explantion and definition are badly placed. Fresheneesz 20:00, 30 May 2006 (UTC)

I added some dynamic braking material to the Diesel-electric article. On further thought, I'm wondering whether there's enough detail to justify a separate article. Dynamic braking is a natural outgrowth of Diesel-electric propulsion, so it is really a subsystem of the overall package. Bigdumbdinosaur 17:03, 18 February 2007 (UTC)

References needed
This article currently has no sources for its information, so I've tagged it as unreferenced. We need these not only to back up the statements made but to expand on them to provide some details. For instance, there is no real information about how regenerative brakes came to be. The article currently says they are "descended from dynamic brakes", but there is no separate article on the latter. The earliest date is a vague "mid-20th century", by which time the ancestors of these brakes were already implemented in trains, etc. Clearly there must have been more history than this. Does anyone have some sources for these details? Thanks. ~ Jeff Q (talk) 09:20, 10 June 2006 (UTC)

I have added some cross references with other articles to describe the history, but sources are still needed. ~ Bryan 19:50, 23 Aug 2006 (UTC)

I have updated and changed the section about use of KERS in F1. The citation to comments from Max Mosley were not accurate with regards to formula one cars being completely hybrid by 2013. It has been introduced, the teams are fitting the systems and will race with them for the first time this year.

Instead I cited recent comments from the teams.

At some point I'll find more details of tests of KERS in formula one.

Daniel.finnan (talk) 01:05, 14 January 2009 (UTC)

Clutter
I think the current regen braking article is cluttered and somewhat disorganized. References to dynamic braking should be eliminated, as they are not germane to the article (except clarification should be kept to indicate that dynamic and regenerative braking are not the same). Bigdumbdinosaur 17:06, 18 February 2007 (UTC)

I'll try to find references for my facts but for now they come from professional knowledge. I'm not sure about the US, but in the UK Rheostatic braking is distinct from dynamic braking. Rheostatic braking being the dissipation of braking energy through resistor grids. As stated regenerative braking returns the generated current back to the line to be used by an accelerating train in a nearby section or back to the supply grid. Research and development continues into acceptable methods of energy storage.

The traction supply may not always be receptive to regenerated current and so in most practical applications a regenerative braking system also has the ability to use Rheostatic braking. Dynamic braking describes such a system. Three of the London Underground Rolling Stock uses dynamic braking 92TS (Central Line), 95TS (Northern Line) and 96TS (Jubilee Line). The system used by the 92TS is known a Dynamic Blending. As electrical brake is ineffective below 10mph the use of the friction brake has to be blended in as the electrical brake cannot maintain the demanded deceleration rate. The 92TS has motors driving every axle and so dynamic braking can be employed at every position. The 95TS and 96TS, however have either 2 and 3 trailer cars respectively in the train formation. These trailers don't have motors and so cannot brake electrically. The system used on these stocks are known as Cross Blending. The braking control unit measures braking rates for each car and for the unit as a whole and balances the braking from the electrical and friction brakes. The electrical brake in used in preference.

The big benefit of regenerative braking is for urban railways and metros where the trains have a short journey time between stations 2 to 3 minutes on London Underground. Regenerative braking metros around the world can safe up to 45% of traction energy requirements.

As I say I don't have references for this that are available in the public domain, but I hope this help to direct the arguement. If am able to find public domain references I will add.

Kinda Like
So this is kinda like down shifting in a car and using the transmission to slow down? HeadMouse 11:47, 14 May 2007 (UTC)HeadMouse
 * Only in the sense that the passengers experience a similar sensation as compression brakeing. Though regenerative braking is far better in that you get to keep the energy such that you can use it again later.  It's also much quieter. --D0li0 08:58, 15 May 2007 (UTC)


 * Yes, downshifting is a form of flywheel kinetic energy conservation, but the engine+flywheel cannot store much energy (momentum) because is has a small inertia. Also, the friction in the engine causes the energy to dissipate in just a few seconds. --MasterHD (talk) 20:22, 3 October 2008 (UTC)

Omission of mechanical potential energy storages
Regenerative Braking isn't exclusive to the conversion of kinetic energy into electrical energy. It can also refer to the transfer of kinetic energy into potential energy (compressed air or oil) via pneumatics or hydraulics while breaking. See, for example, this article at www.greencarcongress.com for its description of Regenerative Braking. See also hydraulic launch assist at www.designnews.com ~ Five 5 fingers 17:07, 14 Aug 2007 (UTC)


 * I agree with this. "Regenerative braking" is a broader topic that involves converting kinetic energy into another form of energy (besides lost heat or material wear) whether it be electrical, elastic, thermal, pressure, gravitational, other forms of kinetic, etc. It seems so far only electrical energy has been widely used in vehicles, but elevators and garage doors use weights and springs as a form of regenerative braking. I am currently designing a regenerative braking bicycle for my senior design project, but it uses springs. I suggest creating subsections in this article for each type of energy that wants to be discussed in more detail.
 * MasterHD 09:43, 23 September 2007 (UTC)


 * I too agree with this. I think there should be at least one new section for mechanical potential energy (as opposed to electrical or chemical potential), for compressed fluid, springs (elastic), and where applicable, weights (gravitational). They could be 3 new sections, or 3 subsections under a section something like 'Storage as mechanical potential energy'. Hey!, and I'm also designing a spring-storage (possibly pressure-storage) regenerative braking bicycle, and came here looking for some figures and known issues for spring- and pressure-systems. JamesHaigh (talk) 00:34, 5 November 2012 (UTC)

WikiProject class rating
This article was automatically assessed because at least one WikiProject had rated the article as start, and the rating on other projects was brought up to start class. BetacommandBot 16:31, 31 August 2007 (UTC)

F1 KERS
The article says "KERS simply transfers the kinetic energy to a flywheel in the F1 car’s transmission when the driver presses a “boost” button." I am fairly certain this is the wrong way around, the energy is released from the flywheel when the driver presses boost. Any objections to changing it? Abhi.mittal (talk) 13:35, 17 May 2008 (UTC)


 * You're correct of course. The article originally said "The energy stored in the flywheel can then be used by the driver by pushing a “boost” button" which is more logical than my edit. Suckindiesel (talk) 22:47, 17 May 2008 (UTC)


 * Erm, so should it be changed? Sorry if I'm hesitating, new around here! Netghytu (talk) 19:11, 18 May 2008 (UTC)

Regenerative braking and towed vehicles
Is it possible to recharge an electric car with regenerative brakes while being towed by riding the brakes ever so slightly not to engage the friction brakes? Towel401 (talk) 18:08, 30 June 2008 (UTC)

Why, yes. It most certainly would work, but the tow truck driver would probably object to you charging your car with his fuel... IF he found out. Swiftek (talk) 21:18, 12 December 2008 (UTC)

Honda
Hi i removed this statement "The Honda Racing F1 Team became the first team to introduce and test a development F1 KERS system on track in May of 2008" it needs a cite and is wrong anyway, Mclaren introduced KERS in to Forumula one back in the 90's, but it was banned. —Preceding unsigned comment added by 62.173.86.208 (talk) 17:31, 8 July 2008 (UTC)

Low speed??
"The regenerative braking effect rapidly reduces at lower speeds, therefore the friction brake is still required in order to bring the vehicle to a complete halt." What is the source for this rubbish? Electric motors (appropriately controlled) can provide constant torque down to zero speed. This statement would be appropriate if aerodynamic brakes were being discussed. As it stands, I feel it is dangerous nonsense and should be removed from the article. —Preceding unsigned comment added by 92.238.216.129 (talk) 19:39, 23 November 2008
 * Well I fail to see how it's dangerous, but if it's incorrect it should be removed. Do you know a source that confirms what you're saying?  TastyCakes (talk) 20:12, 23 November 2008 (UTC)


 * I intrigued by the claim that this is "rubbish" & "dangerous nonsense" & look forward to some real world rail examples of regen, or even dynamic, braking down to zero speed. By the way, the source of this nonsense was an EMD loco manual. Suckindiesel (talk) 00:39, 24 November 2008 (UTC)


 * "Dangerous?" I don't see how.  But, I think they meant that there is no fundamental reason why an electrical device that converts mechanical force into electricity (like what happens in elec regen) cannot do so AND STILL provide useful resistance to torque (braking force) even at very low or zero RPM.  Even the most basic understanding of electrical generators will tell you that.  There is no need for specific reference in this case.  Either through large enough windings, mechanical gearing or other means, it is certainly possible.  I'm betting that it is just impractical for some reason.  Otherwise friction brakes would only be used for emergencies and parking.  I make this point because there is potentially a huge amount of efficiency to be gained by low-speed regen braking since most braking occurs at lower speeds where natural drag from wind, tires, etc. is much reduced.


 * Using the aerodynamic braking mentioned as an example, if the braking foil surfaces are big enough (very large parachutes for instance), they would provide braking force even at very low speeds. The size of the foils would be so large however, it would quickly become impossible to carry them on the vehicle and/or use them repeatedly.


 * Can anyone provide specific reasoning as to why elec regen systems don't work well at low speeds? It would be a good addition to the article.  Swiftek (talk) 22:20, 12 December 2008 (UTC)


 * Practical considerations come into play at lower speeds. With decreasing speed, output of tracion motor operating as a generator falls which is compensated for by increasing field current. However, the field current eventually exceeds the current rating of the motor winding & cannot be increased any further, resulting in decreasing breaking effect as speed decreases.Suckindiesel (talk) 16:56, 15 January 2009 (UTC)


 * Electric motors when given a constant input voltage, produce a torque inversely proportional to the RPM speed (power output is constant). Electric generators don't produce a constant output voltage given varying input speed (RPM). The brake torque produced depends on the speed of the input shaft. i.e. an electric generator will absorb kinetic energy based on the input RPM's and output a varying braking torque. When the amount of kinetic energy approaches 0 as the vehicle slows, the regenerating brake torque also drops to almost nothing as does the output voltage. And so stopping would take a long time without friction brakes to absorb that last remaining bit of kinetic energy. MasterHD (talk) 05:52, 26 January 2009 (UTC)


 * The ability to produce torque is not dependent on the motor but rather the drive. A modern locomotive/EMU equipped with induction/PM motors is capable of operating in all four quadrants and, hence, capable of producing full braking torque even at zero speed. This is not always true for older types of drives. Hence, if electric braking at low speed is possible or not depends on the particular drive. —Preceding unsigned comment added by Tommykjellqvist (talk • contribs) 15:05, 19 August 2010 (UTC)

KERS
The system uses 400V, 200A circuitry... according to the F1 Australia 2009 pre-race show on SPEED. 76.66.193.69 (talk) 05:56, 29 March 2009 (UTC)

History
From the article:
 * An early example of this system was the Energy Regeneration Brake, developed in 1967...

Try ca 1908 - Krieger Electric Carriage - also petrol/electric hybrids !

--195.137.93.171 (talk) 21:08, 13 April 2009 (UTC) —CZmarlin (talk) 22:25, 13 April 2009 (UTC)
 * Outstanding information! It is now added to the article. Thanks for the reference!

There has been development in regen brakes in e-bikes, see for example https://stealthelectricbikes.com/2018/06/07/how-does-regenerative-braking-work-for-an-electric-bike/.

Dynamic braking link
disagrees with this article in that it says dynamic braking can be regenerative. Only one of them can be correct. Betaben (talk) 11:53, 28 July 2009 (UTC)

Importance of second place in Hungarian GP 2009
It says here: "Vodafone McLaren Mercedes became the first team to win a F1 GP using a KERS equipped car when Lewis Hamilton won the Hungarian Grand Prix July 26th 2009. Their second KERS equipped car finished fifth." Surely, it is more important to note that first and second place were both KERS cars, rather than just note that the second car of a specific team came 5th. After all, this is an article about how well KERS works, not how well the team did. Betaben (talk) 11:56, 28 July 2009 (UTC)

Car Manufactures
"In November 2008 it was announced that Freescale Semiconductor would collaborate with McLaren Electronic Systems to further develop its KERS for McLaren's Formula One car from 2010 onwards. Both parties believed this collaboration would improve McLaren's KERS system and help the system filter down to road car technology". this is old news as 2010 KERS is out. Also under Car Manufactures not relevant. Suggest a separate article for KERS in F1.--Mrebus (talk) 17:14, 30 July 2009 (UTC)

How about some numbers?
Designers of The Very Light Car discussed their design on public radio, giving a 30% figure for either RB efficiency, or overall savings from RB -- but it was not clear if the base was overall fuel consumption or pre-braking momentum! It would be good for the article to include some verifiably typical #s for --Jerzy•t 21:08, 17 September 2010 (UTC)
 * 1) % RB savings on whole-trip energy (for urban and highway)
 * 2) efficiency of conversion of battery-charge to momentum, and of RB conversion back, for
 * 3) for representative speeds, and
 * 4) for accelerations that are
 * 5) very gradual,
 * 6) typical for, e.g., drivers whose median accelerations put them at 24th, 49th, or 74th-percentile respectively, and
 * 7) maxiumum.

Regen is typically quoted as recovering 30% of the braking energy in an urban drive. As such the overall benefit to fuel consumption is nothing to write home about, but is a step change. I think it is about 5%. 95% of stops are at 0.3g or less, regen should be able to cope with that. The round trip efficiency from motor to battery to motor is unlikely to exceed 60%. Greglocock (talk) 23:22, 17 September 2010 (UTC)

Rewording introduction
I've taken the liberty of rewording the introduction. The fourth sentence was grammatically and syntactically incorrect (possibly due to an incomplete edit?), and the first paragraph repeated a couple of statements. I felt it was possible to say this more clearly and in fewer words. I've also changed the wikilink at compressed air to point at the more specific Compressed air energy storage article, since the flywheel wikilink similarly points to the article on flywheel energy storage rather than flywheels in general (IIRC this is WP policy anyway). No toes trodden on, I hope? RedGreenInBlue (talk) 14:29, 28 October 2010 (UTC)

I've devised a significant improvement to regenerative braking
Does anybody here have contacts that can provide a "way in" to somewhere like Bosch? I'm in Germany already. I don't have the time or resources to prototype and patent my idea myself, but I would like to see if I've got something here. Email me on wbraveheartw@gmail.com if interested. —Preceding unsigned comment added by 84.155.216.235 (talk) 10:13, 11 January 2011 (UTC)

Merge Kinetic energy recovery system
Kinetic Energy Recovery System redirects here, but Kinetic Energy Recovery Systems (plural) is a separate page. This seems sub-optimal to me. I have no expertise in this area to find out how to merge them and no time to do the merge them myself, so I'd like to ask anybody who can to have a look and see if this can and should be done. — SkyLined (talk) 15:35, 20 October 2011 (UTC)


 * I think Kinetic energy recovery system (as it is now) should be merged into the Kinetic energy recovery systems section of this article, then probably the article should be rearranged and renamed back to Kinetic energy recovery system, Kinetic energy recovery systems, or just Kinetic energy recovery. I've added the merge template to the articles. JamesHaigh (talk) 01:58, 5 November 2012 (UTC)


 * Reorganised a bit, see below. About KERS: ... I think it contains too much detail which deserves its own page (Kinetic energy recovery system): I propose replacing this section with a short summary and leaving the 'Main article: ...' link.


 * I'm not sure what you mean: to merge both articles and name the result 'Kinetic energy recovery'? I'd rather keep this page as an overview of the idea and, briefly, different applications, and have the other (current Kinetic Energy Recovery System) be more of a 'History of KERS in automotive systems' as it is now.  Thoughts?  --StevenDH (talk) 21:18, 23 November 2012 (UTC)
 * the plural issue seems to have gone. My vote is for keeping the motor sport article separate from the general article.
 * there is another case of use of the name 'Kinetic energy recovery' - UK army & others use this name for the use of momentum in a moving vehicle to recover a stuck vehicle - mentioned in Vehicle recovery (military) — Preceding unsigned comment added by 109.144.133.2 (talk) 20:03, 9 June 2013 (UTC)

RB in linear motors
Sorry if this is a stupid question. This article mainly focuses on conventional rotary motors (understandably, as they are used by most railways in the world), but is regenerative braking also possible with linear induction motors? JaneStillman (talk) 20:24, 16 March 2012 (UTC)

Yes, see Stribrsky, A., Hyniova, K., Honcu, J. and Kruczek, A., 2007, June. Energy recuperation in automotive active suspension systems with linear electric motor. In Control & Automation, 2007. MED'07. Mediterranean Conference on (pp. 1-5). IEEE. Specialsymbol (talk) 14:43, 10 February 2020 (UTC)

Reorganisation
I reorganised this article into a section on general principles, one on conversion to electric energy (copied most of the text into that) and one on mechanical energy. As suggested above, a lot of non-electric topics could go into that last section. I made the KERS stuff part of this, but I think it contains too much detail which deserves its own page (Kinetic energy recovery system): I propose replacing this section with a short summary and leaving the 'Main article: ...' link. Now just adding a small example of flywheel application... --StevenDH (talk) 19:23, 23 November 2012 (UTC)

Thermodynamics
This section in the article appears to be mistitled; it does not have any information on thermodynamics.

Unless the braking system is capturing and using heat, any technical information on energy capture/conversion/use should be discussed in relevant terms, e.g.: kinetic forms (mechanical) and potential forms (electric). — Preceding unsigned comment added by Pf416 (talk • contribs) 13:10, 11 March 2014 (UTC)

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Requested move 1 May 2022

 * The following is a closed discussion of a requested move. Please do not modify it. Subsequent comments should be made in a new section on the talk page. Editors desiring to contest the closing decision should consider a move review after discussing it on the closer's talk page. No further edits should be made to this discussion. 

The result of the move request was: moved per request. Favonian (talk) 17:19, 8 May 2022 (UTC)

Regenerative brake → Regenerative braking – For some reason I feel 'regenerative braking' sounds better, while 'regenerative brake' sounds wrong and also seems to be much less used. Both sound like a verb to me, but I might be wrong. Sauer202 (talk) 16:41, 1 May 2022 (UTC)
 * Support. Braking broadly suggests the whole technology and operation, whereas brake seems more narrowly just the machinery itself. The article's lede begins with "regenerative braking". ╠╣uw [ talk ] 20:45, 2 May 2022 (UTC)
 * Support - I read it as being either "braking" being the verb, or "brake" being the noun, as with other articles about brakes/braking. In this case, I think it seems more natural to use the very version since the article is more about the action itself (in a similar way to Dynamic braking) rather than the object performing the action (like in Parking brake or Disc brake). A7V2 (talk) 01:46, 4 May 2022 (UTC)


 * Support. Regenerative braking is better because it represents the lede, which starts with "Regenerative braking is...". "Regenerative brake" also sounds wrong in my opinion, although take this with a grain of salt because I'm not a native speaker. Klrfl   Talk!  14:17, 8 May 2022 (UTC)

The discussion above is closed. Please do not modify it. Subsequent comments should be made on the appropriate discussion page. No further edits should be made to this discussion.