Filed under: Emerging Technologies, MPG, SAE World Congress
SAE World Congress: Zeroshift transmission promises better performance and efficiency
While I was walking down the aisles at the SAE World Congress last week in Detroit, I stopped by the Zeroshift booth to speak with some of the engineers and salespeople from the company. On display was a small demonstration of how their replacement for the common synchro's inside manual transmissions works. I was rather fascinated by the device, to be honest. I could apply torque by turning the output shaft of the transmission and manipulate the two gears in the transmission with my other hand. I can back up their claims, at least in this small example, that the shifting is quick, with no loss of torque while in between shifts. There is a seamless hand-off from one gear to the next. I was also impressed by the simplicity of the design. This is apparently the second version of the transmission that has been developed, and was made to fit inside a standard transmission. The system is also much simpler than other automated manual gearboxes currently on the market.
The salesperson on hand was able to verify that we will soon see versions of their transmission in new vehicles, starting with motorcycles. He indicated that the motorcycle in question would come from overseas, but would be sold in America. I would not be surprised to see automotive applications showing up soon after. The Zeroshift team also mentioned that they had won an engineering award at the SAE show. Why is this a green technology? A certain amount of fuel is saved by using this transmission, as there is never a loss of torque to the output shaft. Think of what you do when you shift a manual transmission. First you step on the clutch, then change gears and lastly let off the clutch and continue on your merry way. Most drivers instinctively smooth out the shifting process by attempting to match the engine speed from shift to shift, and there is a certain bit of "lag-time" where the engine is running at higher than required RPM's and is uncoupled from the driving wheels. This is eliminated with the Zeroshift transmission. In stop and go driving, this could add up to significant savings.
Until the automakers in general start to make a broad switch to petroleum alternatives and electric vehicles, further refining of the existing, established solutions, like the manual transmission, may be the best short-term solution to improving our fuel mileage and reducing harmful emissions.
[Source: Zeroshift]
Reader Comments (Page 1 of 1)
MikeW 7:34PM (4/26/2007)
I asked a chief engineer from Yamaha about this replacing the craptastic FJR1300AE system, and he said "I haven't heard of zeroshift, I'll have to look into it.'
Motorcycles, yes. Cars, no.
Zeroshift doesn't have any answers to the fundamentals of the design, the large impulse when changing gears, besides opening the clutch, which defeats the purpose of having a continous connection between engine and transmission.
Also their emperical data looks like crap. Same car, totally different accleration off the line.
http://www.zeroshift.com/products/gearboxtrace.htm
When upshifting with a stick, you are in overrun, so no fuel will be saved there. It might make double clutching passe though.
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ksmith 8:59AM (4/27/2007)
Wow, I forgot about this company. I remember hearing about them four years ago. At the time they wouldn't reveal how they accomplished their zero-lag shifting. Now that I've seen the system, it looks pretty slick.
I agree that this is probably of limited use in passenger cars, where shift quality matters, but it could be a boon for racing cars.
The discrepancy between the two graphs that Mike talks about doesn't bother me at all. It could be a case of different internal ratios between the two Tremecs, or a different final drive. The thing to look for is the fact that the cars putting power down 100% of the time.
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Howard Lee Harkness 1:49PM (4/27/2007)
I suppose my beloved stick shift will eventually go away, and I won't be able to buy one anymore, but maybe I can keep my current manual-transmission pickup until I'm ready for an EV conversion, which might not even need a transmission.
Meanwhile,
1) I get better gas mileage than I would with an automatic transmission (I also consistently beat the EPA estimates that were posted on this truck).
2) The standard transmission is cheaper.
3) It lasts longer.
4) It needs less maintenance.
5) When it *does* wear out, it costs less to repair or replace.
6) It reduces the odds that my truck will be stolen, because a standard transmission reduces its appeal to thieves, and most low-life auto thieves can't drive one anyway.
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MikeW 2:45PM (4/27/2007)
http://www.hbm.com/company/apps/SEURLF/ASP/SFS/TASK.SHOW/SOL./CAT.192/MM.4,43,-1/SFE/app_view.htm
The figure 4 here is from simulation, look how slow it accelerates. 0-30 in ~9.5 seconds
The figure 3 graph, 0-50mph? in 18.5 seconds.
That wouldn't be very scientific to change the gear ratios or the axle ratio when they are attempting to extol the the virtuals of their technology.
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MikeW 2:46PM (4/27/2007)
virtues.
Oops.
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Dominique 12:05PM (5/27/2008)
In a recent interview by French newspaper Le Figaro, Christian Streiff, PSA's CEO told that PSA has no double clutch transmission in developpement but follow another cheaper way. I wouldn't be suprised if this automated transmission be based on the zeroshift technology, if it really works.
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