A perpetual 10-Best winner will surely arrive better than ever before. Wayne Gerdes – CleanMPG – June 9, 2017 Camouflaged 10th gen 2018 Honda Accord Earlier today, Honda released even more details on its upcoming all-new Honda Accord scheduled for release late this year. The all-new, completely redesigned 10th gen 2018 Honda Accord will follow the 9th gen which is already America's best-selling midsize sedan. New means new exterior, interior, chassis, chassis tuning, features and of course all-new powertrains. Three efficient Accord powertrains are eager to see the light of day within the all-new 2018 Accord. Honda stated it will include two direct-injected and turbocharged I4 engines, something similar to the highly regarded 1.5T in the Civic and CR-V mated to either a 6-speed MT or CVT. Sound familiar? The second will be the a new 2.0L turbo mated to an all-new 10-speed AT and a 6-speed MT. 10th gen 2018 Honda Accord 10-Speed AT The third is going to be the most desirable to many of us imho. An all-new next-generation hybrid drivetrain using the brands best in segment, hyper efficient 2-motor hybrid powertrain under the hood. The 1.5L and 2.0L turbo I4s will be produced at Honda's Anna, Ohio engine plant. The Accord's CVT transmission will be manufactured at the company's Russells Point, Ohio plant, and its new 10-speed automatic transmission will be produced in the company's Tallapoosa, Georgia plant. Honda added that the Accord nameplate has been purchased by more than 13 million new owners since 1976. The real question(s) are how much more efficient is the 1.5L-T and Hybrid drive-trains in the all-new 10th gen Accord going to be?
No more 6-cyl Accords. Some Accord fans will lament that but the new turbo L4s are so powerful and so much lighter, and so much easier to work on that I wouldn't buy the 6-cyl even at a discount. Seems to me that a 10-speed auto would spend a lot of time searching for gears. Not sure if I would like more than 6 or 7 in an engine with a broad, flat torque curve.
I thought that about an 8 speed automatic, then I drove the A6 TDI with the 8-speed. It was very smart, and never felt like it was hunting.
Kind of like how many people would like for CVTs to work? (I'm okay with current workings of the eCVT in the Prius and Fords, and the CVT in the Crosstrek from my brief experience with one.)
These newer designs can skip around and select the exact ratio for a speed/load situation. The 10 speed may work as a 5 or 6 speed under light loads. Checking the US patent for the Honda 10 speed, it has 7 clutches with three engaged at any given time to provide a selected ratio. From any given ratio, it can shift to another gear as long as it involves releasing only one of the three clutches and applying another. In the patent, the 7 elements are listed as B1/B2/B3/C1/C2/C3/C4, and there's also F1 - a freewheel or roller clutch in parallel with B3. So if, for example, the current ratio is 2nd gear, which uses B1, B2 and C3, it can skip to: 3rd - B1, B2, (C2) 4th - B1, (C2), C3 ...where the parenthesis show the part that engages to provide the different ratio. The patent seems to show two dog clutches - B1 and C4 - with C4 used only for reverse and so is not a problem with applying/releasing. But B1 is "on" for 1st-5th and "off" for 6th-10th. With 5th at 1.3:1 and 6th at 1:1, that shift will need very careful programming to avoid the death-zone limbo that infects the dog-equpped ZF 9-speed transaxles.
I remember reading reviews of the Acura TLX with an 8-speed DCT with torque converter. One of the criticisms was that it hunted for gears. My Acura RSX has a 5-speed which is perfectly adequate. The transmission has all the gears engaged all the time and uses clutches to lock a pair of gears to their respective shafts. The gears are all very tall which I like. More gears means more weight and cost, and I think the point of diminishing returns on the type engine the Accord has and the load it's designed to drive is much fewer than 10 gears.
The DCT - by design - can only shift between odd and even gears, so it will have to do that sequential shift-shuffle. In a planetary gear automatic, more gear ratios don't necessarily weigh much more (or cost more) although it depends on how the power flow is structured. The Honda 10 speed uses four planetary gearsets - same as the ZF, Hyundai/Kia and GM/Ford 8-speed designs. The Honda design uses 7 clutches but only 5 are friction elements that can add drag when they are released. That minimizes the power loss associated with automatics. There is a Chrysler transmission - the 545RFE - that is marketed as a five speed automatic but is actually a six speed. The missing gear, called "two prime", is used only when downshifting. It's taller than 2nd and shorter than 3rd. The idea was carried into the 62TE transaxle (used in FWD cars and vans), where it becomes "four prime" and allows a ratio optimized more for passing than pulling. I suspect the Honda design will skip some gears during the long journey from #1 to #10, using some specifically for downshifting, and otherwise fine-tuning engine rpm in steady-state highway cruising by bumping up or down one cog.
