How does an automatic transmission know when to change gears?
>>15044924
Thats the joke.
It doesn't. It retards up when climbing up hill or getting on dirt or gravel.
Hydraulic pressure from throttle and small computer circuits
>>15044924
In modern cars, the ECU reads the throttle pressure and downshifts/upshifts.
In some cars like Rolls Royces or even the S Class, even the GPS is used to map the gears you'll need for a given section of the road.
older trannies use hydraulics
>>15045162
this is why automatics are called witchcraft
>>15045162
what the fuck
>>15045162
No
>>15045162
>all the time and money spent designing this crap
>and manuals are still better
i lel
>>15045162
I wasn't gonna sleep tonight anyway
depending upon the following factors
heat/load/incline/rpm/throttle position/downkick rod/selector level/alignment of the constellations/fluid change interval
it will decide to activate one of three pistons, and shift into the wrong gear 99% of the time.
>>15045162
>I don't have to understand it, I just just have to find the broken thing, replace it, and put it back together VERY CAREFULLY.
>>15045335
There's a reason why they just throw away broken torque converters.
>>15045335
>oshit where did this part come from
>welp, time for a new car
>>15045162
This disturbs me.
>>15045330
>>15044924
Inside each transmission is a mini dagumi that shifts at the right time for optimal gas milage
>>15045340
kek
>>15045330
Its like something from doom. Cybernetic, covered in blood and made of evil.
>>15045554
Daewoo logo has 6 fronds, satan confirmed.
Here is one neat mechanical way. https://www.youtube.com/watch?v=22vGpEnwoRk
You can do smoother and more sophisticated things if you're not constrained to lego pieces though.
Dunno. Easiest to say is it works with throttle and your car position (uphill/downhill)
Thats how it works on my golf 7
As soon as i leave the brake the car accelerates. If im uphill and stop, then release again the car applies throttle on its own to accelerate fluently.
Was actually surprised to see that not all autos work the same way with the brake.
Was shoocked when i realized that my friends m6 rolled backwards when he left the break. Never had that happened in my golf. Mostly driven manual so im kinda new to automatic stuff. Like the gearbox of my golf a lot though
>>15045709
You're stupid
>>15045111
A Class doesn't do that though. It'll use the GPS for its headlights, but the transmission "only" uses the cameras and sensors to figure out what kind of road it's on, elevation etc, in addition to the regular methods of modern automatics (checking acceleration input, engine RPM, driver's profile when manually shifting).
>>15045717
>says the tripfriend
>>15045162
What kind of autistic savant designs these things?
>>15045709
Lol
>>15045823
It's simpler than it looks. The operation is similar to a regular transmission
>move rod
>uncover and uncover holes in the floor of the "maze" (nah it's just a collection of A to B channels all shoved into a small box)
>fluid path changes
Old school:
Spinning governor that spun to a speed then shifted.
new:
Computer sees RPM,speed,Load, and traction to determine when to shift.
>>15045289
>>15045300
>>15045181
>>15045321
these fags haven't seen an Automatic trans valve body before.
fucking NON-car guys
>>15045823
a computer designed the layout most likely.
but the operation is simple in principle.
>>15045162
This is what the 4spd auto transmission for my 99 accord looks like.
When it broke all shops refused to do a rebuild and instead I got a junkyard replacement.
>>15045162
>dat hydraulic computer
>>15045330
>this is my transmission lel
more modern transmissions like since the 80s at least use an ECU and solenoids to shift the flow of transmission fluid and shift into that gear. such is life with no clutch. just wait until you explain how the hydraulic coupling works to these bus riders.
some smaller cars use an electronic control with a manual transmission like the getrag designed smartcar transmission.
>>15044924
Magic and gnomes
>>15044924
They learned on a manual first.
>>15045162
Pal, my career is in transmission testing, and I can honestly say that all autos use hydraulics, as do CVTs and DCTs.
>>15045339
That's a valvebody, not a torque converter.
'They' throw away torque converters because the vast majority of them are non serviceable. They come crimped or welded together.
>>15046959
No it's not.
>>15046973
Alright, you got me, I don't work for a multinational firm that specializes in efficiency testing and development.
Our North American headquarters is in Auburn Hills, Mi. I'll leave you to guess which company.
>>15045823
>>15046480
my dad worked on military hydraulic computers years back (can't EMP a fluid based computer). imagine a large room sized version of this
>>15047020
1996 called, they want their UI back.
>>15047219
What kind of UI would be more suited for pure numerical displays? A simple, lightweight wins when it comes down to minimizing computation power when data logging at 1000Hz
>>15045162
oh.
i always thought those patterns were because the engineers had too much time in CAD.
>>15047224
One that was aligned properly, didn't use disgusting hard to read gradients and gauges with overlapping text and managed to fit within one window without having to scroll around
>>15047240
Alignment doesn't matter when you have to set up the UI differently for every single trans test or type that is being tested. Pretty much every single value that matters is right in one column anyway, with the graphs and displays mainly being parity for reference.
The buttons with the gradient are rarely used, and they are quite easy to read when at a proper angle to use the screen anyway.
It wasn't possible in that case to fit all of the charts onto one screen, as the one in the lower left (which is only tracking voltage) is just precautionary, and scaled so that the values that matter are within view without scrolling down the page.
>>15047240
this. that program looks like hot garbage.
>>15044924
How exactly is a rainbow made? How exactly does the Sun set? How exactly does a posi-trac rear end on a Plymouth work?! It just does.
>>15047224
LEL the ui doesn't take away from your 1000 samples a second processing. Not when it's just a question of layout and icons because one is already in place.
You also have a disgusting nut hair on your keyboard.
>>15047020
You work for the Pistons? Thats pretty cool.
The automatic transmissiom knows when to shift at all times. It knows this because it knows what gear it isn't. By subtracting what gear it is from what gear it isn't, or what gear it isn't from what gear it is (whichever is greater), it obtains a difference, or deviation. The transmission subsystem uses deviations to generate corrective commands to shift the gears from a gear where it is to a gear where it isn't, and arriving at a gear where it wasn't, it now is. Consequently, the gear where it is, is now the gear that it wasn't, and it follows that the gear that it was, is now the gear that it isn't.
In the event that the gear that it is in is not the gear that it wasn't, the system has acquired a variation, the variation being the difference between which gear it is, and where it wasn't. If variation is considered to be a significant factor, it too may be corrected by the torque converter. However, the transmission must also know what gear it was.
The automatic transmission gearshifting computer scenario works as follows: because a variation has modified some of the information the transmission has obtained, it is not sure just what gear it is. However, it is sure what gear it isn't, within reason, and it knows what gear it was. It now subtracts what gear it should be from what gear it wasn't, or vice-versa, and by differentiating this from the algebraic sum of what gear it shouldn't be, and what gear it was, it is able to obtain the deviation and its variation, which is called error.
>>15046049
>CAD
>in the 30's
back in the old days, engineers designed awesome hydraulic computers just by imagination, paper and pencil ... and it worked! not like today's "I LUV SCIENCE" fags that can't even build a bicycle without CAD and 3D printing
>>15047322
An amazing engineering feature to pull off in the late 30s just because Americans were too damn lazy to learn how to shift without grinding its gears into oblivion or invest in better syncs
>>15047081
Troll harder fag
-10/10
>>15046959
you dont know shit then. you must only work on hydraulic systems. which would confuse you into thinking that all hydraulic transmissions are auto hence all autos are hydraulic.
https://en.wikipedia.org/wiki/Smart_Fortwo
>>15047322
10/10
First thought I had was of that video when I saw this thread.
>>15047269
>I don't understand how computers work, the post
>>15048445
1000hz signal processing is literally nothing
>>15048445
l am a programmer.
>>15044924
In my experience? They don't. It's a random decision, or based on throttle position.
Throttle open? DOWNSHIFT FOR MORE REVS, DISREGARD ACTUAL SPEED. REDLINE ENGINE AT HIGHWAY SPEEDS
Throttle closed? SHIFT UP FOR EFFICIENCY, DISREGARD INCLINE.
>>15048456
It is when most computers on cars still have the computing power of a ti83 calculator and a multimeter
>>15045330
>its self aware
The transmission in my car apparently learns from your habits in an effort to be a bit more accurate. Still a pain in the ass in traffic because it likes to trundle along at 1200 rpm at 40km/h.
>>15045303
>>15045823
most of the later ones were designed using computers
>>15049673
my transmission's shifting also gets better over time because i'm the one operating it
>>15046037
was about to say something similar....kek
>>15046503
Ford Fiesta auto trans uses something like that.
It's shit though. Apparently it's bad at finding the right gear, and doesn't slip very well at low speeds.
>>15049673
I'm also guessing that after disconnecting the battery, the transmissions acts strange to you.
>>15052378
Yeah, so does the Focus. I can tell you from experience that it feels like someone who has never driven a stick shift is operating the automatic transmission.
This thread is confirmation that if I ever want to learn legitimate information about something new, I won't come on here. The entertainment factor was there though.
>>15047020
let windows update to 10
don't be a pussy
>>15052664
no one here knows how an automatic transmission works.
Auto Transmissions might as well be turbo encabulators.
>>15044924
there's a small elf inside every auto trans which is shifting the gears for you. this is why only special techs should open autos, because they have the tools to catch the elf.
if the elf escapes, your trans is fucked.
>>15047322
Only me and >>15047491 got it
>>15044924
it doesn't
>>15052688
>being a pussy and just letting it update to the inferior Windows
>>15048445
Updating your icons and layout within the existing UI will have zero effect on your speed, dumbass
