[car fanatics]

Source
Photo credit: Hyundai
January 19, 2012
By: CF staff

Not content with only eight-speed automatics in its transmission portfolio, Hyundai also confirmed that it is developing a ten-speed autobox in-house. The announcement begs the question: At what point does the complexity and packaging of gears become redundant in comparison to a CVT? Given the rampant ratio-envy in the industry, we may never know.

[RougeRiver]

Quote:At what point does the complexity and packaging of gears become redundant in comparison to a CVT?

Apparently Honda feels that six is enough and that is why they are going to offer a CVT with the next Accord.

It is a valid question.

[REVolution]

I think 6 is enough, but then I drove a 7-speed S-Class and found how low it revs on the highway. It can still be done with 6 gears. Porsche uses 7 also and it seems to work out well.

[the_koof]

Six, seven, eight, ten speeds. At this rate, manufacturers are going to be consulting with Eaton in how to make eighteen speed boxes for your Accord and Fusion.

But in all seriousness I believe six speeds is the ideal for cars in performance and efficiency.

[redsky]

10sp tranmission...yeah right..

[Gixser995]

I feel that may be too many. Heck, I think even 8 speeds might be a bit excessive. Still, I prefer any regular transmission over a flippin' CVT.

[Tonavi]

CVTs are wonderful for city driving. The only part where they suck is for performance driving. Outside of that they are fine if you're somewhat normal. The Altima I drove I preferred the CVT to the 5A.

[ChaiLatte]

Torque-less cars would benefit from this. I always found it odd how smaller, weaker cars got the four speeds while the 300+hp ones got 6+ speeds. Granted, your paying more and deserve more, but they can at least give compacts 6 speeds. I also have a feeling this transmission should be able to skip unnecessary gears while accelerating. And hell, I'd take a 20 speed auto before taking a CVT.

[LovemyPathfinder]

Cvt is way better than a conventional planetary automatic in all areas except towing and makes the most sense for regular cars because is it fuel efficiency and low costs. Reliability is the same. Though it's no where as good and direct as a dsg or sct trans, and will never be as fun as a manual.::

[McLovin]

hmmm, I am not seeing added efficiency here. Only an engineering -manufacturing exercise, that looks good on a brochure.

[REVolution]

I wonder how long a step down to a low gear from a high gear will take. Going from ten to four is a massive jump.

[the_koof]

I have driven a car with a CVT and still prefer a traditional automatic or dual clutch over it. I like having it shift gears and the engine doesn't just sit there and whine as in a CVT. That and I just like the sound.

[Tonavi]

Trannies like like the Lexus 8A can drop several gears at a time so hunting shouldn't be a big problem.

[RougeRiver]

Automatic have always been able to skip gears quickly during a step down.

The old fully hydraulic systems had an actuator in which pressure was applied on one side as a function of the vacuum caused how far the gas pedal was pushed down with the other side being fed a pressure by a governor pump that proportional to wheel speed.

Lets say you were going along at 65 mph holding steady. The governor would be applying a pressure to keep the gear ratio tall and the slight throttle opening would provide little pressure to oppose that. Tromping on the gas pedal to pass a truck would cause a spike in pressure counter to the governor and move the actuator such that the fluid relays to engage either a one or two gear kickdown were set.

The modern automatics use stored shift map tables and fuzzy logic with the inputs being vehicle speed, rate of gas pedal depression, degree of depression and history of driver behavior to figure out how many gears is wanted in a step down.

The above is why one must take magazine reviews with a grain of salt. If a C&D or MT (leadfoot) reviewer gets a car that was just tested by Consumer Reports in an economy review ( Mr Milktoast foot), the tranny will still be figuring on step downs that would please Mr Toast, but piss off Mr Lead.

In short, if the code writing is good, then the number of possible ratios should not displease.

The thing that pisses off drivers is the constant hunting as the tranny goes into a fuel economy mode during highway driving as the car meets slight up and downgrades. All that those added gears really do is give more windows of opportunity for the ICE to be more optimally loaded. The good systems isolate the shifts so that the driver is unaware of them.