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Brazilian invention, really ? https://www.byri.net/2021/09/04/night-road-the-automatic-gearbox-this-french-invention/ The first hydraulic automatic gearbox technology which was widespread was from French origin (or rather the patent used, USA compagnies were sued after 1945 for infringment). This article is a bit surprizing and confusing. The patent from Gaston Fleischel was indeed used during decades by US compagnies (which lost before the courts), not sure about the Brazilian technology.
There are no citations and the arguments are that there are whatever losses due to pumping and pressurizing the automatic and it is even argued that the human physical and mental power provided by gear shifting plays any considerable part. Now, anyone who has ever been in a manual and automatic car knows that 1. in manual you gear shift basically as little as possible because every time you do so it stops the entire engine transmission for the time it takes you to react, press the pedals and what not and you have to concentrate on hitting the gear correctly, 2. in a car with automatic you drive constantly on very low rpm, e.g. 2000 rpm, whereas in the same car, same engine, etc. with manual transmission you run every gear from maybe 3000 to 6000 rpm. You just cannot get anywhere near as low as the automatic can, because you just can't gear shift as often as it would be required to keep constant rpms and you can't hit the gears properly if gear shifting from very low rpm.
And that's really the main factor to energy efficiency: hitting the very optimal rpms of the engine all the time. I think that every single factor mentioned in the current section is marginal at best, if not even irrelevant or plainly wrong. Now there might be all sorts of different cars and types and engines and transmission systems, but from the ones I know that were build both as manuals and automatics, the automatics have effectively been far more fuel efficient (maybe 20-30%) opposed to reasonably driving with manual. Would be nice if someone who is more educated could correct that section. — Preceding
unsigned comment added by
77.10.28.244 (
talk)
07:13, 14 May 2013 (UTC)
Oh, and btw. I am talking about actual cars on real roads run by real people. That means, considering real circumstances like city traffic, uphill, downhill, etc. Of course, if you run a car with manual at constant 90km/h in some wind tunnel in the highest gear it will beat the automatic, no question. But that's not very realistic, is it?
Well it depends on what type of automatic, but for the automatic described in the article, yeah, they are much less efficient. CVT and MMT/DSG-type automatics can be more efficient but they're horrible to drive unless you're driving smoothly on a flat road.
The Torque converter autos in the article are much nicer to drive but are always losing power because of the way torque converters work - To describe it in a way that's easy to visualize, imagine two fans, one spinning to 'blow' the oil against the other fan.
Obviously, the 'blowing' fan will always spin faster than the receiving fan - These are the pumping losses that are described.
In lower gears and under load, a manual will destroy a torque converter for fuel efficiency and power delivery - If you've ever tried to tow something heavy with an auto vs. a manual up a hill, you'd know this. That said, most modern torque converters 'lock' at higher gears so that both shafts spin at the same speed with no loss.
Citations are available all over the place - Just look at the mpg and CO2 figures for any manual vs torque converter auto (e.g. http://www.parkers.co.uk/cars/reviews/facts-and-figures/hyundai/i40/tourer-2011/running-costs/ since I was looking at it just now). The figures for the torque converter are usually much worse than for the manual; The only cases where they aren't are for CVT (Gutless (As in sod-all torque), high-revving under load, but can achieve high efficiency when driven gently) and MMT/DSG-type autos (Basically manual gearboxes with computer-controlled clutch and gear shifting) 77.101.174.194 ( talk) 21:01, 18 June 2013 (UTC)
I just read this whole thing and I don't get how the transmission actually works, or how it can change from one gear to another. This article is overly technical.
As someone who understands how an automatic transmission works, I would say that I could not get an idea of how it works, from this article. It is not so much that the article is overly technical, as that it is poorly written, and inaccurate; it does not actually explain how an automatic transmission works, how it shifts gears, or alternatively, how it changes the ratio of engine speed to wheel speed. In fact the very first sentence is simply incorrect. Not all automatic transmissions change gear ratios. What they all do is change the ratio of engine speed to wheel speed. Very simple. It should have been the first thing that the article says. Continuously variable transmissions, a type of automatic transmission, accomplish providing a desired ratio, by changing pulley ratios, not "gear ratios." Nor do ATs allow an engine to "provide a range of range of speed and torque outputs for vehicular travel." That is simply incorrect. Rather, it is at the output of the AT, not the output of the engine, where an appropriate speed for vehicular travel is provided. The engine still provides an "inappropriate" speed at its output; but the output of the engine, still inappropriate for vehicular travel, is input to the AT; then it is at the output of the AT where the appropriate speed is provided. Perhaps it would have been much simpler to have said "It enables a vehicle's wheels turn at a rotational speed at which they provide a desired vehicle speed, while connected to an internal combustion engine, via the AT, that is turning at the relatively high rotational speed at which it needs to run, in order to provides the amount of power and torque needed to move the mass of the vehicle forward at that speed." However, although more accurate, that would not be a complete description of what an AT does. The last sentence of the first paragraph, "The number of forward gear ratios is often expressed for manual transmissions as well (e.g., 6-speed manual)" has nothing to do with automatic transmissions. It is talking about the nomenclature sometimes used in describing manual transmissions! Nomenclator ( talk) 13:59, 4 October 2017 (UTC)
It might be worth working up something about Constantinesco's non-hydraulic torque converter of the 1920s. Unfortunately I don't have a link at the moment, but I seem to recall altavista finds it easier than google for some reason. PML.
This was completed on January 5 2007 KG
It would be useful to include a section on the shifter mechanism found in automobiles with an automatic transmission. This comes to mind as I work on D (disambiguation) and encounter "D for Drive". I know of three main types: push-button, floor shifter (illustrated in this article) and steering column shifter. Questions that come to mind are a) are there any other styles? and b) is "D for Drive" the same across all languages, or might it be (looking at Wiktionary) "F for Fahren" in German or "V for Vehar" in Ido (though I'd be verrry surprised to see a gear selector encoded for Ido :) ). Thanks for thinking on this and perhaps editing it in. Regards, Courtland 02:13, 29 September 2005 (UTC)
I think the symbols for the transmissions have been standardized, so every carmaker is allowed to use the same letters in the same order. On another note, the BMW and Mercedes's shifter "stalk" is worth mentioning as well. 220.133.92.72 ( talk) 20:04, 1 September 2008 (UTC)
Some cars, e.g., the early (1961) Pontiac Tempest, had the transmission selector on the dashboard, next to the ignition switch and radio (IIRC). There were only four choices: R, N, D, and L (i.e., no P). 71.131.218.173 01:04, 20 July 2006 (UTC)
The gear Automatic Transmission Modes section was very confusing, and really could stand to be reformatted. Vendor specific information really should be below general information, for example the information about Honda and Acura models appears ABOVE the more traditional idicators in generic form. I've moved the section about vender specific modes to the bottom, and made minor changes to the overdrive, drive, and "2" entries for clarification. Jo7hs2 03:20, 28 October 2007 (UTC)
Did you know that all Honda automatics are actually hydraulically operated manual transmissions with torque convertors in place of the clutch? The transmissions of the Chapparral race cars of the 1960's, such as the famous Chapparral 2J 'Fan Car', were similar as they used a torque convertor instead of a clutch, however the synchro-less 4-speed gearbox was manually shifted.
Some Japanese "kei" cars (yellow license plate, with a 650cc engine for reduced tax) have a bizarre combination auto gear box. Two fixed ratio low gears, and then a CVT gear above for regular driving. Confirmed in the Suzuki WagonR, and Daihatsu Move, and not in the Subaru Vivio. Unfortunately, I don't know enough about how they work to put an entry in the article, and it'll be difficult to find an english speaking engineer to explain. Given how underpowered these engines are (I estimate under 50bhp), it's probably an attempt to eke out a little more power, and it certaintly seems to help for going up mountains.
There is no mention of the AL-4 gear, in the models list. This gear is used by all/many of the recent models of French cars Peugeot, Renault, Citroen . Can you add a link to it, and a list of cars where it is used. It has had many reliability problems. —The preceding unsigned comment was added by 89.0.228.55 ( talk • contribs) .
Were not Mercedes (rather than BMW) the first to offer a five speed automatic transmission? If I remember correctly it was available in their 1989 SL?
What are the actual failure modes for an automotive tranny? For example, a worn/slipping clutch plate will cause the torque converter to not couple properly, leading to power loss at hill climbing and/or highway speeds. This leads to the build up a lot of turbulence in the torque converter, which results in a lot of heat being dumped into the tranny. Now, every consumer brochure states that heat kills trannies, but how is it doing this? Is the high heat warping the valve body or something? Are some bearings getting blown out because hot tranny fluid can't protect them any longer ? ??? linas 17:48, 22 May 2007 (UTC)
By the way, what do you call a gearshift on the steering pad, instead of off of it. -- PJ Pete
Marketing lingo right now seems to label them as "paddle shifters" when they are on the sides of the steering wheel. The handful of vehicles (mostly modified cars) that have shift mechanisms directly IN the steering wheel are generally just called shift buttons, or something like that. If my assumption that "steering pad" means the surface of the steering wheel... Jo7hs2 03:23, 28 October 2007 (UTC)
The article sais: "In some cars (notably those sold in the US), the driver must have the footbrake depressed before the transmission can be taken out of park." Shouldn't it say pressed? Alessandro Malfatti ( talk) 00:44, 7 May 2008 (UTC)
The problem with "depress" and "depressed" is that the word has an unrelated meaning suffering from extreme sadness, a form of mental illness. 76.21.8.213 ( talk) 02:08, 18 June 2008 (UTC)
Can you please explain what exactly still needs copyediting? I don't really see it. Arienh4 (Talk) 12:58, 12 June 2008 (UTC)
In the article, is there actually a section on how the automatic transmission actually works? Or is the link at the bottom to HowStuffWorks the closest it gets? Nonagonal Spider ( talk) 07:30, 29 August 2008 (UTC)
I don't understandand the following. Is it a bad english, bad joke or is it me? Thanks
Bang (B or I)- This allows the car to unlock and turn the sensors on some cars to allow if the drive is not engaging properly. This is used for cars that have to be careful from speeding alot of times. This is used only for the summer and fall. —Preceding unsigned comment added by Drevokocur ( talk • contribs) 11:02, 8 September 2008 (UTC)
Volkswagen Group, Mitsubishi, BMW and others using this type of transmission (pioneered commercially on the Veyron) are NOT an automatic transmission even though they will shift under the control of a computer as they have no torque converter. They have a proper clutch, it is electronically-actuated. So really they are a computer-controlled manual transmission are they not?
After learning on and driving manual transmission for many I have trouble getting used to a torque converter automatic. Part of it comes from driving short distance with cold engine and transmission. But what I really do not understand is torque lock up. For example when accelerating after a traffic light:
In case I cruise with lock up and then kick down, how does switching gears work internally? I guess it is like:
This should give a backwards jerk, which is indeed the case, but it is almost unnoticeable, thus I am unsure. Should I avoid kick down, since it means opening break discs under full engine load? My engine has relative low torque and the ECU cannot close throttle at switches automatically. Anyways kick down is so much faster than down-shifting on a manual transmission.
Above 3500 RPM my torque converter looses efficiency and is locked up and only used as a visco-clutch while closing break disks to avoid overheating of the disks, though I never tried running into RPM redline.
The delay if switching from N or P to D or R is due to the silly sequential gear knob? Why does the automatic not use an H with N in the middle?
How much energy is needed for the oil pump (compared to the engine oil pump)? How much energy is lost due to break disk and lock up slippage? The torque converter is not efficient in coupling mode, therefore it is then locked up. Coupling mode is a typical condition in driving in a lot of driving situations and not only at low power cruising and thus an integral part of the driving experience on a high quality torque converter transmission. The driver avoids the region between torque converter acceleration mode and lock up by dictating clear transitions using the throttle, much like the gear switch.
I hope some of you with more knowledge can include an automatic for manual-guys section into the article! A CVT is much more automatic transmission. A DSG is a much more efficient transmission.
Arnero ( talk) 09:37, 23 March 2009 (UTC)
lasombra bg ( talk) 19:57, 9 March 2011 (UTC)
I think the picture of the Lexus IS-F's tranny at the top of the article should be removed due to it not being an automatic at all. It is a semi-automatic. —Preceding unsigned comment added by 70.24.181.11 ( talk) 00:02, 3 April 2009 (UTC)
"Since these gearboxes also have a throttle kickdown switch, it is impossible to fully exploit the engine power at low to medium engine speeds[dubious – discuss][citation needed]."
I left this paragraph there. I also added somewhere the fact about the fly-wheel clutch in automatic transmission (that the engine does not slow down the car when the driver steps of the throttle) and thus more nervous usage of the brakes in cars with automatic transmission.
When DSG first came out I really liked the concept. Then I tried it and testdrove a Golf GTI. I selected manual mode and I accelerated in the first gear with full throttle (like I always do). At around 3000RPM I tried to shift to the second gear but was ignored (because of the kickdown switch) -- I thought that I had made a mistake. Later when driving in the third gear I again used full throttle and the engine downshifted by itself. Thus this gearbox was out of the question for me.
Thus, if the driver cannot use full throttle without the engine either downshifting or ignoring an upshift command, how can the driver exploit all the available power at low to medium RPM?
I know, I could still use full throttle, if I somehow could avoid triggering the kickdown switch. But I'm unable to do so and also quite unwilling to learn to do so. This is an unnecessary problem caused by sick engineering.
I also thought about this in normal Automatic (not DSG). The engineering problem is to map a given pedal input (at a given speed) to a gear and throttle. Since lenght of pedal way in an automatic is not longer than in a manual, one would expect a stronger sensitivity of the pedal in an automatic, since in order to map all available gears for a given speed (which may be at least 3) an automatic would have to map the range of idle until full throttle at least 3 times to the available pedal way. Also there is the requirement, that given a very small difference in pedal input which may cause a downshift but which should not cause a different acceleration. Thus by this requirement alone, an automatic prevents one from using every available gears (for a given speed) together with every possible throttle input.
In general: I have the impression, that with an automatic one is unable to exploit the power of the engine at low to medium RPM. Since there is nobody testing this (by e.g. measuring acceleration from 0..100km/h with the limit of max. 3000 or 4000 RPM) I can only say this is an impression. But I think an automatic kind of trains the driver to avoid full throttle -- and people in the US a very well "trained by there cars". Also the sedated way of driving in the US
(nobody uses full throttle, nobody shows off with high acceleration at speeds higher than 30mil/h, people simply block the highway at any speed even lower than the speed limit)
and the competitional way of driving in Germany
(people actually are forced by law to yield the left lane, if somebody wants to pass. This also and especially includes driving on uphill roads.)
and the difference in ratio of automatic to manual between US and Germany proves my point indirectly. —Preceding unsigned comment added by ExcessPhase ( talk • contribs) 05:41, 13 June 2010 (UTC)
I sold my 2007 RS4 (which I loved) and got a 2016 Mercedes CLA250 4Matic (which I hate). This car also has a manual gearing mode -- like a DSG. But there are many problems with it. Since there are no reliable evaluations of cars anywhere to be read, I think this will be my last car with any kind of automatic. I also think that the engine computer in this Mercedes is especially tuned for the US tastes. This includes
I've read an evaluation of an 2017 Audi S4 at https://arstechnica.com/cars/2017/04/revenge-of-the-nerds-the-all-new-2018-audi-s4-and-s5/ This evaluation contains information about a smart delay in the throttle and NO CRITIQUE of this.
Just search the web for "kickdown manual mode" and one finds a few. Also there are some ECU modifications which disable the kickdown switch in manual mode. I also heard rumors that the Audi RS8 sold in Germany does disable the kickdown in manual mode.
— Preceding unsigned comment added by 2605:6000:EC57:7600:2989:493C:B2E:BE73 ( talk) 22:19, 22 April 2017 (UTC)
After discussing a possible edit at Epicyclic gearing (see Talk:Epicyclic_gearing#Switching_gears_by_use_of_pinions ) and coming to the conclusion that the info of that particular edit didn't belong there, it seems that instead, this article needs a cleanup for clarity.
In general, the headlines presently go as follows:
6 Manually controlled automatic transmissions
For clarity, I propose this arrangement:
Allot of confusing things of the text are taken out with this setup, ie manual control for example is not possible in CVT's, so having a level one headline for this makes the whole confusing, ...
Finally, add the references from the old edit as noted at Talk:Epicyclic_gearing#Switching_gears_by_use_of_pinions, and add a much needed image (showing fluid coupling + planetary gearbox 91.182.7.40 ( talk) 10:37, 15 December 2010 (UTC)
91.182.29.99 ( talk) 14:50, 18 December 2010 (UTC)
The section on 'Brake (B)' mode seems to imply that all non-hybrid engines use compression braking. Petrol engines use vacuum breaking - compression braking is found on diesel engines due to their lack of a throttle butterfly to create the vacuum. The unspecified Toyotas that have this mode may all be diesel, but I think it gives an inaccurate impression. 'Engine Braking' on it's own would be an improvement, as this covers both modes. — Preceding unsigned comment added by Trippy72 ( talk • contribs) 06:51, 16 November 2012 (UTC)
I don't know what things like in your respective regions/countries/space-time-coordinates, but here the term 'automatic transmission' is very ambiguous and doesn't necessarily refer to just torque converters.
In fact, torque converters are becoming increasingly rare in new vehicles here due to high CO2 tax penalties, and are giving way to CVT and MMT/DSG-type gearboxes which are generally included in the term 'automatic transmission'.
IMHO, this article should be a stub; Maybe give a summary of the broad meaning of 'automatic transmission', and then give a list of different types of autobox with links to specific articles (e.g. Torque Converter, CVT, and whatever the heck the correct term for MMT and DSG-type autoboxes are (Computer controlled clutch? Elecontrically actuated clutch and gears??))
What ya think? 77.101.174.194 ( talk) 21:13, 18 June 2013 (UTC)
"For hybrid cars, this mode converts the electric motor into a generator for the battery ( Regenerative Braking)." From what I've read, this is incorrect—B mode involves engine braking and actually wastes more energy than D in most situations, and regenerative braking is mainly controlled by the brake pedal. See [3] and [4]. Benny White ( talk) 19:24, 11 March 2016 (UTC)
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I have removed 2 citations that attribute the creation of the hydramatic transmission to brazilian inventors José Braz Araripe and Fernando Lehly Lemos. Searching for these names in google show me that the same phrases are parroted across multiple articles in both Portuguese and English mostly without any sort of reference, which heavily imply some sort of cyclic reference or that the whole thing is just heresay.
I have done a brief search for any sort of academic work that reference these guys, and the only one that came up with these names was this FYP thesis named "A TECNOLOGIA DA TRANSMISSÃO AUTOMÁTICA DE VEÍCULOS COM RELAÇÃO AO CONSUMO DE COMBUSTÍVEL" by Kléber Henrique Oliveira Holanda, which contains has the exact same paragraph that was twice present on this wikipedia article and cites as a source the this journal named "Dual clutch transmissions : Lessons learned and future potential" by Bernd Matthes as a source for this information.
Uppon scanning the article to check for any mentions of the brazilian inventors, none came up. In fact, I think it doesn't even mentions the Hydramatic transmission. Additionally, while searching for sources that might back up the statements I have removed, I have briefly seen mentions that the renowned brazilian author Paulo Coelho might have claimed in a biography that one of his relatives (which was one of the previously mentioned inventors) had sold the blueprints to GM back in the day.
I am not going to check the story past this point, but I'm confident this is either heresay or some sort of historical injustice that will never be corrected due to lack of evidence. And since both phrases have been marked for better citations since 2014, I felt it was safe to assume that are none to be provided. 109.78.34.192 ( talk) 21:06, 26 September 2019 (UTC)
Show me the picture to the transmisión please 2600:8800:722B:3000:619E:3DBC:330F:AFF8 ( talk) 07:56, 31 August 2023 (UTC)
"Low (L): This position, required by U.S. law, provides for engine braking on steep hills." - that can't be current since no modern car (for a while now) has L! 104.228.237.30 ( talk) 13:37, 15 June 2024 (UTC)
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Brazilian invention, really ? https://www.byri.net/2021/09/04/night-road-the-automatic-gearbox-this-french-invention/ The first hydraulic automatic gearbox technology which was widespread was from French origin (or rather the patent used, USA compagnies were sued after 1945 for infringment). This article is a bit surprizing and confusing. The patent from Gaston Fleischel was indeed used during decades by US compagnies (which lost before the courts), not sure about the Brazilian technology.
There are no citations and the arguments are that there are whatever losses due to pumping and pressurizing the automatic and it is even argued that the human physical and mental power provided by gear shifting plays any considerable part. Now, anyone who has ever been in a manual and automatic car knows that 1. in manual you gear shift basically as little as possible because every time you do so it stops the entire engine transmission for the time it takes you to react, press the pedals and what not and you have to concentrate on hitting the gear correctly, 2. in a car with automatic you drive constantly on very low rpm, e.g. 2000 rpm, whereas in the same car, same engine, etc. with manual transmission you run every gear from maybe 3000 to 6000 rpm. You just cannot get anywhere near as low as the automatic can, because you just can't gear shift as often as it would be required to keep constant rpms and you can't hit the gears properly if gear shifting from very low rpm.
And that's really the main factor to energy efficiency: hitting the very optimal rpms of the engine all the time. I think that every single factor mentioned in the current section is marginal at best, if not even irrelevant or plainly wrong. Now there might be all sorts of different cars and types and engines and transmission systems, but from the ones I know that were build both as manuals and automatics, the automatics have effectively been far more fuel efficient (maybe 20-30%) opposed to reasonably driving with manual. Would be nice if someone who is more educated could correct that section. — Preceding
unsigned comment added by
77.10.28.244 (
talk)
07:13, 14 May 2013 (UTC)
Oh, and btw. I am talking about actual cars on real roads run by real people. That means, considering real circumstances like city traffic, uphill, downhill, etc. Of course, if you run a car with manual at constant 90km/h in some wind tunnel in the highest gear it will beat the automatic, no question. But that's not very realistic, is it?
Well it depends on what type of automatic, but for the automatic described in the article, yeah, they are much less efficient. CVT and MMT/DSG-type automatics can be more efficient but they're horrible to drive unless you're driving smoothly on a flat road.
The Torque converter autos in the article are much nicer to drive but are always losing power because of the way torque converters work - To describe it in a way that's easy to visualize, imagine two fans, one spinning to 'blow' the oil against the other fan.
Obviously, the 'blowing' fan will always spin faster than the receiving fan - These are the pumping losses that are described.
In lower gears and under load, a manual will destroy a torque converter for fuel efficiency and power delivery - If you've ever tried to tow something heavy with an auto vs. a manual up a hill, you'd know this. That said, most modern torque converters 'lock' at higher gears so that both shafts spin at the same speed with no loss.
Citations are available all over the place - Just look at the mpg and CO2 figures for any manual vs torque converter auto (e.g. http://www.parkers.co.uk/cars/reviews/facts-and-figures/hyundai/i40/tourer-2011/running-costs/ since I was looking at it just now). The figures for the torque converter are usually much worse than for the manual; The only cases where they aren't are for CVT (Gutless (As in sod-all torque), high-revving under load, but can achieve high efficiency when driven gently) and MMT/DSG-type autos (Basically manual gearboxes with computer-controlled clutch and gear shifting) 77.101.174.194 ( talk) 21:01, 18 June 2013 (UTC)
I just read this whole thing and I don't get how the transmission actually works, or how it can change from one gear to another. This article is overly technical.
As someone who understands how an automatic transmission works, I would say that I could not get an idea of how it works, from this article. It is not so much that the article is overly technical, as that it is poorly written, and inaccurate; it does not actually explain how an automatic transmission works, how it shifts gears, or alternatively, how it changes the ratio of engine speed to wheel speed. In fact the very first sentence is simply incorrect. Not all automatic transmissions change gear ratios. What they all do is change the ratio of engine speed to wheel speed. Very simple. It should have been the first thing that the article says. Continuously variable transmissions, a type of automatic transmission, accomplish providing a desired ratio, by changing pulley ratios, not "gear ratios." Nor do ATs allow an engine to "provide a range of range of speed and torque outputs for vehicular travel." That is simply incorrect. Rather, it is at the output of the AT, not the output of the engine, where an appropriate speed for vehicular travel is provided. The engine still provides an "inappropriate" speed at its output; but the output of the engine, still inappropriate for vehicular travel, is input to the AT; then it is at the output of the AT where the appropriate speed is provided. Perhaps it would have been much simpler to have said "It enables a vehicle's wheels turn at a rotational speed at which they provide a desired vehicle speed, while connected to an internal combustion engine, via the AT, that is turning at the relatively high rotational speed at which it needs to run, in order to provides the amount of power and torque needed to move the mass of the vehicle forward at that speed." However, although more accurate, that would not be a complete description of what an AT does. The last sentence of the first paragraph, "The number of forward gear ratios is often expressed for manual transmissions as well (e.g., 6-speed manual)" has nothing to do with automatic transmissions. It is talking about the nomenclature sometimes used in describing manual transmissions! Nomenclator ( talk) 13:59, 4 October 2017 (UTC)
It might be worth working up something about Constantinesco's non-hydraulic torque converter of the 1920s. Unfortunately I don't have a link at the moment, but I seem to recall altavista finds it easier than google for some reason. PML.
This was completed on January 5 2007 KG
It would be useful to include a section on the shifter mechanism found in automobiles with an automatic transmission. This comes to mind as I work on D (disambiguation) and encounter "D for Drive". I know of three main types: push-button, floor shifter (illustrated in this article) and steering column shifter. Questions that come to mind are a) are there any other styles? and b) is "D for Drive" the same across all languages, or might it be (looking at Wiktionary) "F for Fahren" in German or "V for Vehar" in Ido (though I'd be verrry surprised to see a gear selector encoded for Ido :) ). Thanks for thinking on this and perhaps editing it in. Regards, Courtland 02:13, 29 September 2005 (UTC)
I think the symbols for the transmissions have been standardized, so every carmaker is allowed to use the same letters in the same order. On another note, the BMW and Mercedes's shifter "stalk" is worth mentioning as well. 220.133.92.72 ( talk) 20:04, 1 September 2008 (UTC)
Some cars, e.g., the early (1961) Pontiac Tempest, had the transmission selector on the dashboard, next to the ignition switch and radio (IIRC). There were only four choices: R, N, D, and L (i.e., no P). 71.131.218.173 01:04, 20 July 2006 (UTC)
The gear Automatic Transmission Modes section was very confusing, and really could stand to be reformatted. Vendor specific information really should be below general information, for example the information about Honda and Acura models appears ABOVE the more traditional idicators in generic form. I've moved the section about vender specific modes to the bottom, and made minor changes to the overdrive, drive, and "2" entries for clarification. Jo7hs2 03:20, 28 October 2007 (UTC)
Did you know that all Honda automatics are actually hydraulically operated manual transmissions with torque convertors in place of the clutch? The transmissions of the Chapparral race cars of the 1960's, such as the famous Chapparral 2J 'Fan Car', were similar as they used a torque convertor instead of a clutch, however the synchro-less 4-speed gearbox was manually shifted.
Some Japanese "kei" cars (yellow license plate, with a 650cc engine for reduced tax) have a bizarre combination auto gear box. Two fixed ratio low gears, and then a CVT gear above for regular driving. Confirmed in the Suzuki WagonR, and Daihatsu Move, and not in the Subaru Vivio. Unfortunately, I don't know enough about how they work to put an entry in the article, and it'll be difficult to find an english speaking engineer to explain. Given how underpowered these engines are (I estimate under 50bhp), it's probably an attempt to eke out a little more power, and it certaintly seems to help for going up mountains.
There is no mention of the AL-4 gear, in the models list. This gear is used by all/many of the recent models of French cars Peugeot, Renault, Citroen . Can you add a link to it, and a list of cars where it is used. It has had many reliability problems. —The preceding unsigned comment was added by 89.0.228.55 ( talk • contribs) .
Were not Mercedes (rather than BMW) the first to offer a five speed automatic transmission? If I remember correctly it was available in their 1989 SL?
What are the actual failure modes for an automotive tranny? For example, a worn/slipping clutch plate will cause the torque converter to not couple properly, leading to power loss at hill climbing and/or highway speeds. This leads to the build up a lot of turbulence in the torque converter, which results in a lot of heat being dumped into the tranny. Now, every consumer brochure states that heat kills trannies, but how is it doing this? Is the high heat warping the valve body or something? Are some bearings getting blown out because hot tranny fluid can't protect them any longer ? ??? linas 17:48, 22 May 2007 (UTC)
By the way, what do you call a gearshift on the steering pad, instead of off of it. -- PJ Pete
Marketing lingo right now seems to label them as "paddle shifters" when they are on the sides of the steering wheel. The handful of vehicles (mostly modified cars) that have shift mechanisms directly IN the steering wheel are generally just called shift buttons, or something like that. If my assumption that "steering pad" means the surface of the steering wheel... Jo7hs2 03:23, 28 October 2007 (UTC)
The article sais: "In some cars (notably those sold in the US), the driver must have the footbrake depressed before the transmission can be taken out of park." Shouldn't it say pressed? Alessandro Malfatti ( talk) 00:44, 7 May 2008 (UTC)
The problem with "depress" and "depressed" is that the word has an unrelated meaning suffering from extreme sadness, a form of mental illness. 76.21.8.213 ( talk) 02:08, 18 June 2008 (UTC)
Can you please explain what exactly still needs copyediting? I don't really see it. Arienh4 (Talk) 12:58, 12 June 2008 (UTC)
In the article, is there actually a section on how the automatic transmission actually works? Or is the link at the bottom to HowStuffWorks the closest it gets? Nonagonal Spider ( talk) 07:30, 29 August 2008 (UTC)
I don't understandand the following. Is it a bad english, bad joke or is it me? Thanks
Bang (B or I)- This allows the car to unlock and turn the sensors on some cars to allow if the drive is not engaging properly. This is used for cars that have to be careful from speeding alot of times. This is used only for the summer and fall. —Preceding unsigned comment added by Drevokocur ( talk • contribs) 11:02, 8 September 2008 (UTC)
Volkswagen Group, Mitsubishi, BMW and others using this type of transmission (pioneered commercially on the Veyron) are NOT an automatic transmission even though they will shift under the control of a computer as they have no torque converter. They have a proper clutch, it is electronically-actuated. So really they are a computer-controlled manual transmission are they not?
After learning on and driving manual transmission for many I have trouble getting used to a torque converter automatic. Part of it comes from driving short distance with cold engine and transmission. But what I really do not understand is torque lock up. For example when accelerating after a traffic light:
In case I cruise with lock up and then kick down, how does switching gears work internally? I guess it is like:
This should give a backwards jerk, which is indeed the case, but it is almost unnoticeable, thus I am unsure. Should I avoid kick down, since it means opening break discs under full engine load? My engine has relative low torque and the ECU cannot close throttle at switches automatically. Anyways kick down is so much faster than down-shifting on a manual transmission.
Above 3500 RPM my torque converter looses efficiency and is locked up and only used as a visco-clutch while closing break disks to avoid overheating of the disks, though I never tried running into RPM redline.
The delay if switching from N or P to D or R is due to the silly sequential gear knob? Why does the automatic not use an H with N in the middle?
How much energy is needed for the oil pump (compared to the engine oil pump)? How much energy is lost due to break disk and lock up slippage? The torque converter is not efficient in coupling mode, therefore it is then locked up. Coupling mode is a typical condition in driving in a lot of driving situations and not only at low power cruising and thus an integral part of the driving experience on a high quality torque converter transmission. The driver avoids the region between torque converter acceleration mode and lock up by dictating clear transitions using the throttle, much like the gear switch.
I hope some of you with more knowledge can include an automatic for manual-guys section into the article! A CVT is much more automatic transmission. A DSG is a much more efficient transmission.
Arnero ( talk) 09:37, 23 March 2009 (UTC)
lasombra bg ( talk) 19:57, 9 March 2011 (UTC)
I think the picture of the Lexus IS-F's tranny at the top of the article should be removed due to it not being an automatic at all. It is a semi-automatic. —Preceding unsigned comment added by 70.24.181.11 ( talk) 00:02, 3 April 2009 (UTC)
"Since these gearboxes also have a throttle kickdown switch, it is impossible to fully exploit the engine power at low to medium engine speeds[dubious – discuss][citation needed]."
I left this paragraph there. I also added somewhere the fact about the fly-wheel clutch in automatic transmission (that the engine does not slow down the car when the driver steps of the throttle) and thus more nervous usage of the brakes in cars with automatic transmission.
When DSG first came out I really liked the concept. Then I tried it and testdrove a Golf GTI. I selected manual mode and I accelerated in the first gear with full throttle (like I always do). At around 3000RPM I tried to shift to the second gear but was ignored (because of the kickdown switch) -- I thought that I had made a mistake. Later when driving in the third gear I again used full throttle and the engine downshifted by itself. Thus this gearbox was out of the question for me.
Thus, if the driver cannot use full throttle without the engine either downshifting or ignoring an upshift command, how can the driver exploit all the available power at low to medium RPM?
I know, I could still use full throttle, if I somehow could avoid triggering the kickdown switch. But I'm unable to do so and also quite unwilling to learn to do so. This is an unnecessary problem caused by sick engineering.
I also thought about this in normal Automatic (not DSG). The engineering problem is to map a given pedal input (at a given speed) to a gear and throttle. Since lenght of pedal way in an automatic is not longer than in a manual, one would expect a stronger sensitivity of the pedal in an automatic, since in order to map all available gears for a given speed (which may be at least 3) an automatic would have to map the range of idle until full throttle at least 3 times to the available pedal way. Also there is the requirement, that given a very small difference in pedal input which may cause a downshift but which should not cause a different acceleration. Thus by this requirement alone, an automatic prevents one from using every available gears (for a given speed) together with every possible throttle input.
In general: I have the impression, that with an automatic one is unable to exploit the power of the engine at low to medium RPM. Since there is nobody testing this (by e.g. measuring acceleration from 0..100km/h with the limit of max. 3000 or 4000 RPM) I can only say this is an impression. But I think an automatic kind of trains the driver to avoid full throttle -- and people in the US a very well "trained by there cars". Also the sedated way of driving in the US
(nobody uses full throttle, nobody shows off with high acceleration at speeds higher than 30mil/h, people simply block the highway at any speed even lower than the speed limit)
and the competitional way of driving in Germany
(people actually are forced by law to yield the left lane, if somebody wants to pass. This also and especially includes driving on uphill roads.)
and the difference in ratio of automatic to manual between US and Germany proves my point indirectly. —Preceding unsigned comment added by ExcessPhase ( talk • contribs) 05:41, 13 June 2010 (UTC)
I sold my 2007 RS4 (which I loved) and got a 2016 Mercedes CLA250 4Matic (which I hate). This car also has a manual gearing mode -- like a DSG. But there are many problems with it. Since there are no reliable evaluations of cars anywhere to be read, I think this will be my last car with any kind of automatic. I also think that the engine computer in this Mercedes is especially tuned for the US tastes. This includes
I've read an evaluation of an 2017 Audi S4 at https://arstechnica.com/cars/2017/04/revenge-of-the-nerds-the-all-new-2018-audi-s4-and-s5/ This evaluation contains information about a smart delay in the throttle and NO CRITIQUE of this.
Just search the web for "kickdown manual mode" and one finds a few. Also there are some ECU modifications which disable the kickdown switch in manual mode. I also heard rumors that the Audi RS8 sold in Germany does disable the kickdown in manual mode.
— Preceding unsigned comment added by 2605:6000:EC57:7600:2989:493C:B2E:BE73 ( talk) 22:19, 22 April 2017 (UTC)
After discussing a possible edit at Epicyclic gearing (see Talk:Epicyclic_gearing#Switching_gears_by_use_of_pinions ) and coming to the conclusion that the info of that particular edit didn't belong there, it seems that instead, this article needs a cleanup for clarity.
In general, the headlines presently go as follows:
6 Manually controlled automatic transmissions
For clarity, I propose this arrangement:
Allot of confusing things of the text are taken out with this setup, ie manual control for example is not possible in CVT's, so having a level one headline for this makes the whole confusing, ...
Finally, add the references from the old edit as noted at Talk:Epicyclic_gearing#Switching_gears_by_use_of_pinions, and add a much needed image (showing fluid coupling + planetary gearbox 91.182.7.40 ( talk) 10:37, 15 December 2010 (UTC)
91.182.29.99 ( talk) 14:50, 18 December 2010 (UTC)
The section on 'Brake (B)' mode seems to imply that all non-hybrid engines use compression braking. Petrol engines use vacuum breaking - compression braking is found on diesel engines due to their lack of a throttle butterfly to create the vacuum. The unspecified Toyotas that have this mode may all be diesel, but I think it gives an inaccurate impression. 'Engine Braking' on it's own would be an improvement, as this covers both modes. — Preceding unsigned comment added by Trippy72 ( talk • contribs) 06:51, 16 November 2012 (UTC)
I don't know what things like in your respective regions/countries/space-time-coordinates, but here the term 'automatic transmission' is very ambiguous and doesn't necessarily refer to just torque converters.
In fact, torque converters are becoming increasingly rare in new vehicles here due to high CO2 tax penalties, and are giving way to CVT and MMT/DSG-type gearboxes which are generally included in the term 'automatic transmission'.
IMHO, this article should be a stub; Maybe give a summary of the broad meaning of 'automatic transmission', and then give a list of different types of autobox with links to specific articles (e.g. Torque Converter, CVT, and whatever the heck the correct term for MMT and DSG-type autoboxes are (Computer controlled clutch? Elecontrically actuated clutch and gears??))
What ya think? 77.101.174.194 ( talk) 21:13, 18 June 2013 (UTC)
"For hybrid cars, this mode converts the electric motor into a generator for the battery ( Regenerative Braking)." From what I've read, this is incorrect—B mode involves engine braking and actually wastes more energy than D in most situations, and regenerative braking is mainly controlled by the brake pedal. See [3] and [4]. Benny White ( talk) 19:24, 11 March 2016 (UTC)
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I have removed 2 citations that attribute the creation of the hydramatic transmission to brazilian inventors José Braz Araripe and Fernando Lehly Lemos. Searching for these names in google show me that the same phrases are parroted across multiple articles in both Portuguese and English mostly without any sort of reference, which heavily imply some sort of cyclic reference or that the whole thing is just heresay.
I have done a brief search for any sort of academic work that reference these guys, and the only one that came up with these names was this FYP thesis named "A TECNOLOGIA DA TRANSMISSÃO AUTOMÁTICA DE VEÍCULOS COM RELAÇÃO AO CONSUMO DE COMBUSTÍVEL" by Kléber Henrique Oliveira Holanda, which contains has the exact same paragraph that was twice present on this wikipedia article and cites as a source the this journal named "Dual clutch transmissions : Lessons learned and future potential" by Bernd Matthes as a source for this information.
Uppon scanning the article to check for any mentions of the brazilian inventors, none came up. In fact, I think it doesn't even mentions the Hydramatic transmission. Additionally, while searching for sources that might back up the statements I have removed, I have briefly seen mentions that the renowned brazilian author Paulo Coelho might have claimed in a biography that one of his relatives (which was one of the previously mentioned inventors) had sold the blueprints to GM back in the day.
I am not going to check the story past this point, but I'm confident this is either heresay or some sort of historical injustice that will never be corrected due to lack of evidence. And since both phrases have been marked for better citations since 2014, I felt it was safe to assume that are none to be provided. 109.78.34.192 ( talk) 21:06, 26 September 2019 (UTC)
Show me the picture to the transmisión please 2600:8800:722B:3000:619E:3DBC:330F:AFF8 ( talk) 07:56, 31 August 2023 (UTC)
"Low (L): This position, required by U.S. law, provides for engine braking on steep hills." - that can't be current since no modern car (for a while now) has L! 104.228.237.30 ( talk) 13:37, 15 June 2024 (UTC)