Recent Topics
Ecopia with a front bulge
by nicholas
05/26/17 09:22 AM
How Do Univ. ATF's Meet Many Specs.?
by doitmyself
05/26/17 08:30 AM
Berkeley Professor arrested for Assault.
by pbm
05/26/17 07:28 AM
Oroville Dam Spillway Webcam
by Danno
05/26/17 06:28 AM
RA Clearance Oil Filters.
by dlundblad
05/26/17 06:22 AM
Where part store parts are made and by who
by ram_man
05/25/17 11:36 PM
Isn't it sad they can't predict the weather?
by motor_oil_madman
05/25/17 11:04 PM
recirculation mode makes ac last longer?
by motor_oil_madman
05/25/17 10:17 PM
Supertech ELC & NAPA Cool for 7.3 powerstroke
by T-Stick
05/25/17 10:16 PM
Toyota TGMO 0W20 - VOA
by VolkswagenFox21
05/25/17 09:38 PM
POTUS scolds "Bad Germans" ref auto sales in US
by wemay
05/25/17 08:35 PM
Do thermostats get 'lazy' over time?
by Klutch9
05/25/17 07:38 PM
Goodyear Endurance trailer tires
by another Todd
05/25/17 06:58 PM
What visits your yard?
by funflyer
05/25/17 06:47 PM
LR3 Brake pads
by HoosierJeeper
05/25/17 06:44 PM
Delco synchromesh friction modified MT fluid
by deoxy4
05/25/17 06:41 PM
Out of State Car Purchase Questions
by FirstNissan
05/25/17 06:14 PM
Smitty's Blue Light Special
by Egg_Head
05/25/17 03:56 PM
I ran Castrol 5W-50 for 5000 miles in my bike
by ammolab
05/25/17 03:25 PM
engine oil viscosity
by hamm
05/25/17 03:23 PM
Newest Members
Jes, hamm, Curlscurls, stuka, rodekyll
61656 Registered Users
Who's Online
91 registered (69GTX, 4WD, 3800Series, 64bawagon, 555, 8 invisible), 2404 Guests and 10 Spiders online.
Key: Admin, Global Mod, Mod
Forum Stats
61656 Members
66 Forums
265627 Topics
4389795 Posts

Max Online: 3590 @ 01/24/17 08:07 PM
Donate to BITOG
Topic Options
#3429744 - 07/19/14 11:27 PM Honda AT design...
gregk24 Offline


Registered: 04/13/13
Posts: 5167
Loc: FL, USA
I know the Hondas of old had non planetary auto gear boxes, and were basically "self shifting" manuals. Are the Honda transmissions of today still built the same way? And if so, are these the same as the automated manuals of other car companies, and just not labeled as such?
_________________________
2012 Honda Accord EX-L K24z3
46,xxx miles
PPPP 0w20 / Fram Ultra

2014 VW Jetta SE 1.8T ea888
26,xxx miles
Castrol Edge 0w40 / OEM filter

Top
#3429773 - 07/20/14 12:04 AM Re: Honda AT design... [Re: gregk24]
Kiwi_ME Offline


Registered: 10/24/08
Posts: 1019
Loc: New Zealand
Not much info on that design:
http://world.honda.com/history/challenge/1968hondamatic/page04.html

http://www.sydfynmc.dk/indexdele/mcdatamenu/hondaaargange/historie/1960erne/1968a.html

Aside from a torque convertor and parallel shaft gearbox with dog-clutch gear engagement, it has two multi-plate clutches and a sprag clutch. It seems to have all the parts for an early dual clutch gearbox.

Top
#3429800 - 07/20/14 01:12 AM Re: Honda AT design... [Re: Kiwi_ME]
MrHorspwer Offline


Registered: 12/18/06
Posts: 1286
Loc: Michigan
Honda transmissions have traditionally shared one thing in common with manual transmissions: A single parallel shaft (countershaft) with constant mesh gearing. Outside of that, they are totally different beasts.

Where a shift fork would actuate a synchronizer in a manual transmission, Honda transmissions have a multi-plate, hydraulically actuated and lubricated clutch pack, very similar to the type used in a typical planetary automatic transmission. Honda transmissions still have sprags (one-way clutch) and overrun clutches, like their planetary cousins. Of course, Honda automatics all use a torque convertor as well.

Now, if you want to compare it to a *true* "self shifting manual", you'd have to look at a sequential manual gearbox (SMG). An SMG has all the same parts as a manual transmission: Single dry clutch, single parallel countershaft, synchronizers (or dogs), and shift forks. What it adds is an electro-hydraulic component that, simply put, shifts itself. When it's time to shift, the actuator for the clutch activates (which would be the same as you pressing the clutch pedal), the appropriate actuator moves the appropriate shift fork/synchro (as if you were moving the shift lever), and the clutch actuator releases the clutch (like you were letting off on the clutch pedal). All the motions are the same, except a computer is controlling some electrical actuators in place of your left leg and right arm.

Originally Posted By: Kiwi_ME
side from a torque convertor and parallel shaft gearbox with dog-clutch gear engagement, it has two multi-plate clutches and a sprag clutch. It seems to have all the parts for an early dual clutch gearbox.


When you say "two multi-plate clutches", you have to look at where those clutches are located. On a dual-shift gearbox (DSG), the clutches control the connect and disconnect of the engine at the input shaft, like a traditional manual gearbox clutch would. In a Honda automatic, those "multi-plate clutches" are located in place of a synchronizer (which itself is a type of clutch). It "clutches" a specific power flow through the transmission, just like a planetary automatic does. The 6-speed GM auto in my Equinox also has two "multi-plate clutches" in it. That doesn't make it a DSG.

So, a DSG literally has two clutches. Why does it need two clutches? This is the really important part: A DSG has two clutches because it's has two input shafts! The input shafts are an shaft-within-a-shaft arrangement and each of the two clutches are splined to one of them. Why does it need two input shafts? Another important part: Because it has two parallel countershafts! One countershaft will house all the odd-gears, the other will have even. So, you have one clutch, input shaft, and countershaft for odd gears and another clutch, input shaft, and counter shaft for even gears.

Following the power flow: With first gear selected, clutch 1 (C1) is engaged and clutch 2 (C2) is disengaged. The odd and even shift actuators have 1st gear *and* 2nd gear engaged. Because there are two input shafts and C2 is released, no torque is being transmitted through the second input shaft.

When it comes time to shift, C2 is applied while C1 is released. That's it. 2nd gear was already preselected and torque is now being transmitter to the second countershaft. With C1 released, the odd actuator will transition from 1st to 3rd (this is done by moving a shift fork, just like a manual). Again, with torque going through the first input shaft, odd gears are free to move about at will. When it comes time to change gears again, C1 is applied while C2 is released... and so on. Because the next gear for each upshift is preselected, there is no time wasted actuating anything except the clutches during a shift.

Top