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9 speed automatic shifting improvement

Discussion in 'Mopar News' started by MJAB, Aug 12, 2017.

  1. MJAB

    MJAB Well-Known Member

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    In last days was made public a patent for an "automatic transmission for a vehicle", applicant FCA US LLC, inventors Berthold Martin and Glenn Giudici.

    Patent (WO2017136115) AUTOMATIC TRANSMISSION FOR A VEHICLE
    priority date: 02.02.2016

    https://patentscope.wipo.int/search/en/detail.jsf?docId=WO2017136115&recNum=3&maxRec=449&office=&prevFilter=&sortOption=Pub+Date+Desc&queryString=ALLNAMES:(FCA)&tab=PCT+Biblio

    PDF file: https://patentscope.wipo.int/search/docservicepdf_pct/id00000038865225/PAMPH/WO2017136115.pdf

    The core of the patent is a clutch arrangement, used instead of one of dog clutches, to improve shifting performance of the 9 speed automatic transmission (948TE / ZF 9HP).

    From the patent description text:

    "...
    [0026] In contrast to the typical nine-speed automatic transmission 900, the nine-speed automatic transmission 10 of the present application includes a friction disc clutch as clutch element A. Unlike a dog clutch, disc clutch A provides a smoother and more immediate engagement during shifting, thereby eliminating the rotational synchronization requirements before and during engagement that can cause subsequent potentially objectionable time delays when shifting. As such, disc clutch A provides improvement in shift time and shift quality. Moreover, disc clutch A can be packaged within transmission 10 without extending the length of the typical nine-speed transmission 900, thereby enabling automatic transmission 10 to be used in vehicles designed to accept transmission 900
    ..."

    "... [0032] The systems and methods described herein provide an automatic transmission with improved shifting. The transmission replaces a typical dog clutch arrangement of clutch element A with a disc clutch arrangement. The replacement is such that no change in length or size is required for the transmission. Moreover, the disc clutch A is radially nested within the envelope of the B clutch, which improves packaging. The disc clutch A arrangement eliminates the need for rotational synchronization and subsequent time delays in the transmission function associated with dog clutch A arrangements. Accordingly, the disc clutch A arrangement improves vehicle function when shifting to drive (D) from park (P), reverse (R), or neutral (N), and improves shift time coming out of 8th gear. ..."

    Figure 4 of the patent illustrates main differences.

    The revised(/new) transmission includes now only a single dog clutch.
     
    #1 MJAB, Aug 12, 2017
    Last edited: Aug 12, 2017
  2. jimboy

    jimboy Well-Known Member

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    Hopefully this will resolve some of the issues that people have with the current set-up.
     
    guyverfanatic likes this.
  3. Erik Latranyi

    Level III Supporter

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    Bob Sheaves correctly nailed the dog clutch as the biggest problem in the 9-speed transmission when it was first unveiled.
     
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  4. Chase300

    Chase300 Active Member

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    A good move. If you've owned a marine outboard engine you know the dog clutch "clunk" engagement.
     
  5. MJAB

    MJAB Well-Known Member

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    This table, that illustrates what brake/clutch/dog clutch should be engaged for each selected gear, shows why, for example, 8th to 4th shift could be "problematic".
    To go in 4th have to be engaged dog clutch F and dog clutch A, to do that speed of part in momevent should be synchronized before trying engagement.

    The new version table is exact the same, but instead of the dog clutch A there is a clutch A.

    As happens in many situations, improving one performance usually decreases other performances.

    "... [0024] FIG. 4 is a composite illustration comparing the nine-speed automatic transmission 10 of the present application (shown above line 'X') compared with a typical nine-speed automatic transmission 900 (shown below line 'X'). As illustrated, the typical nine-speed automatic transmission includes a clutch element A formed as a dog clutch 950. The dog clutch 950 arrangement is desirable for its reduced packaging size and reduced drag, which improves transmission efficiency. ..."

    The new solution decreases efficiency of the transmission.

    [​IMG]

    Image from this article.
    The ZF 9HP automatic transmission at a glance (at http://www.car-engineer.com/the-zf-9hp-automatic-transmission-at-a-glance/ )
     
    somber likes this.
  6. ImperialCrown

    Level III Supporter

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    People might be less apprehensive about things like dog clutch engagement in transmissions if they knew what it was that was making the 'clunks' or 'gaps' between certain shifts.
    Just like the JATCO CVT marketing failure with its s-l-i-d-e up and down the ratios felt like it was constantly slipping. It was eerie and unnerving. The CVT is a great concept, but it was presented wrong and was poorly implemented here in the very beginning. Ford gave up on the CVT and went back to conventional 6-speed transaxles in 2006 (except for the hybrid drivetrain).
    Software tweaks have made these transmissions behave better, but more had to be done (hardware) to change U.S. public perceptions. Americans are used to transmissions shifting in 'steps' from birth and the smoother the better. The 8-speed, 9-speed and CVT are not American designs.
    Too many people have unpleasant and expensive memories of transmission failure. Chrysler needs to shed this 'bad' transmission image that has haunted it recently. Transmissions used to last the life of the car and there should be no reason not to expect this degree of service.
    Lifetime ATF (synthetic) has eliminated the need for scheduled maintenance. Under normal driving, it isn't necessary (except under severe duty, like police/taxi/towing). If changing a fluid and filter brings you peace of mind, then go ahead and change it.
    I remember the simple 2-speed automatics and how far we have come since then.
    In 1990, comparing the A-604 transaxle in the domestics to the ZF transaxle in the Premier/Monaco, the A-604 was a much better shifting unit than the 'gaps, clunks and slips' felt in the ZF unit on a road test. The Europeans considered that behavior ''normal' and the ZF units were basically reliable.
    We have taken away the difference in fuel economy between automatics and manuals. I do enjoy stick shifts, but they are difficult to find on the lot and any good salesperson would do their best to talk you out of them (poor resale value).
     
  7. willy4110

    willy4110 Well-Known Member

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    And when we will actually have this change in vehicles?
     
  8. Mike V.

    Mike V. Mopar-nac The Moderator
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    If this design is finalized and in process of being tested, more than likely a running change into the 2019 model year... purely a guess but probably not far off.

    This would be the third major revision to the 9 speed. Constant improvement is a good thing.

    Mike
     
  9. ramajama

    ramajama Active Member

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    We've got the same 9 speed in our Discovery Sport...GRRRR. The shifting and responsiveness in ours has actually degraded since we bought it. It got downright bad. Its now in the shop having a new transmission installed. Im hoping for the best but not expecting too much. I will say that the loaner we have is a lot more responsive down low and is a lot smoother shifter. So yeah, it looks like there has been at least some improvement since it first came out. (We have a very early build 2015 model)
    My wife still loves...err, love/hates... the Disco but we cant keep it past warranty and she wants to swap it for the latest model in a few years, so sounds like the new trans should be out by the time we trade it off.
     
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  10. ECT72

    ECT72 Member

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    Curious/. How much of a decrease in efficiency do you think? Since there is a noticeable lag time in shifts-this is wasted time: efficiency- no? A wash maybe?
     
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  11. dakrt99

    dakrt99 Well-Known Member

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    I feel like they should have resolved all of this before production. It seems like they rushed it into production.
     
  12. AutoTechnician

    AutoTechnician Well-Known Member

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    After reading through the patent, I really wouldn't even call this a revision. It's a substantial re-engineering of the transmission. Like to the point where I'd honestly probably call it a different transmission. They've completely removed one of the dog clutches, and replaced it with a friction clutch.

    However, one of the biggest takeaways from this IMO, is that this is basically Chrysler officially condemning the existing ZF9 speeds. This patent basically admits the ZF9 is so flawed that it required replacing one of its most touted features with a conventional component instead. It's basically saying that no amount of software tweaks are going to fix the existing ZF9 transmissions.
     
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  13. Mike V.

    Mike V. Mopar-nac The Moderator
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    Touted feature? FCA never touted the dog clutch as a feature. Nobody touts a dog clutch as a feature. It’s simply a means to transfer power... in this case it was the wrong choice by ZF and Chrysler is finally fixing it.

    Same case, same shafts, same gears, same basic programming. It’s a revision.

    Mike
     
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  14. AutoTechnician

    AutoTechnician Well-Known Member

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    FCA didn't, but ZF sure did. It was all over the net that the ZF9 was using dog clutches. ZF even brags about it on their website.

    - Cars | 9-Speed Automatic Transmission - ZF Friedrichshafen AG (at https://www.zf.com/corporate/en_de/products/product_range/cars/cars_9_speed_automatic_transmission.shtml )
    - The ZF 9HP automatic transmission at a glance (at http://www.car-engineer.com/the-zf-9hp-automatic-transmission-at-a-glance/ )
    - Ratios Galore: A Deep Look at ZF’s 9-speed Automatic (at http://blog.caranddriver.com/ratios-galore-we-take-a-look-at-zfs-newest-gearbox/ )
    - ZF's 9-Speed 9HP Transmission Puts Dog Clutches On The Leash - The Truth About Cars (at http://www.thetruthaboutcars.com/2014/02/zfs-9-speed-9hp-transmission-puts-dog-clutches-on-the-leash/ )
    Read the patent. You're completely wrong on every single one of those points. The case is different, the shafts are different, the rear clutch hubs are all different and the rear gear train is all different as well. The entire rear-half of this new ZF9 is essentially a completely different transmission now. The "basic programming" will have to be completely different as well. The ZF9's controller has a ton of code relating to synchronizing the dog clutches, timing the engagement of supporting clutches, etc... All of that has to be thrown out with this change. The characteristics of the friction clutch will be completely different.

    Calling this transmission a "revised ZF9" would be like calling the Ford 5R110W a "revised" 4R100. Yeah the basic power-flow is still the same, but the case is different, every single hard part is different and the mechanistic are completely different. Nothing swaps between the two transmissions. They are very different transmissions.

    The same is going to apply with this new ZF9 transmission. I suspect the only major parts that would interchange would be the torque converter, and maybe some final drive stuff.
     
    #14 AutoTechnician, Aug 13, 2017
    Last edited: Aug 13, 2017
  15. freshforged

    freshforged Well-Known Member

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    To your point, this should no longer be called a ZF transmission. It's original design had been licensed from ZF, but this patent has been applied for by FCA...its now more of a FCA design than a ZF. Of course I'm a layman, so my opinion should carry little weight in this matter.
     
  16. Mike V.

    Mike V. Mopar-nac The Moderator
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    ZF uses different programming than Chrysler for other brands. That version of the transmission hasn’t not been used by Chrysler.

    Chrysler has always used a slightly modified version of the ZF design.

    Except you are ignoring the fact that the transmission is all still based on the original, licensed from ZF design. So no, your points above do not stand.

    By your definition, the last revision, in 2016, was “all new” also since very little supersedes and there were minor case changes.

    Sorry, but it is not an all new transmission, it is the third revision of the existing Chrysler produced variant of the ZF 9 speed. Neither Chrysler nor ZF have designed an all new transmission from ground up.

    Mike
     
    #16 Mike V., Aug 13, 2017
    Last edited: Aug 13, 2017
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  17. Mike V.

    Mike V. Mopar-nac The Moderator
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    Nope, it is still based on the original ZF design, thus another revision. (Technically fourth version)

    ZF version (2013)
    Chrysler version 1 (2014)
    Chrysler version 2 (2016)
    Chrysler version 3 (2019)

    ZF has done some updates also, but I have not cared to keep track of Land Rover and Honda transmissions.

    Mike
     
    #17 Mike V., Aug 13, 2017
    Last edited: Aug 13, 2017
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  18. Chase300

    Chase300 Active Member

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    Honda just decided to build there own 10-speed.
     
  19. KCP Worker

    KCP Worker Well-Known Member

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    The FCA built version is called a 948 TE, not a ZF.
     
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  20. patfromigh

    patfromigh Well-Known Member

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    Now, if they could only do something about those impractical final drive ratios.:cool:
     

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