Contour Enthusiasts Group Archives Forums Modifications General Mods 1 gear or single speed automatic transmission

I was reading a review article in my hometown paper about one of the new Audi cars with a continuously variable gear ratio transmission.
It seems its operation is like that of a go-cart transmission where the rpm stays constant but the transmission gear ratio changes.
They coupled it with the turbocharged engine so that it really matches the engines bets rpm.

That pretty much eliminates the need for variable phase cam timing, dual runner intakes, etc. The engine just has to be tuned to operate with a lot of power at one fixed RPM and stay there.
The article said that it kinda felt like the trans was slipping although it wasn't.

Anyone test drive this beast?

warmonger

Yuck. CVT. That thing is a tuners worst nightmare. IIRC for every 5HP you add to the engine, it increases the wear of the belt/tranny by some %25-30.

Great for commutes with economy in mind though.

Once they get variable gear trannies going (with dynamic toothed cogs) then we can talk power.

chris is right... the engine MUST have a specific power.. its a VERY tuned machine... ps honda civic HX had this a while back.

it doesn't have to be a belt, it could be a fully hydraulic unit. engine drives a variable displacement hydraulic pump (wobble plate type) that produces pressure to drive a hydraulic motor coupled to the drive shaft.

When the speed is low the rake angle of the hydraulic pump is small, making the pistons take a short stroke thus making the system pressure, but at a low volume, and as speed increases the rake angle of the wobble plate increases to accomodate the additional volume needed at higher speed.

This type of system has been being used ever since the 60s in turbine engines. They are called CSD or constant speed drives, and are used to turn the AC generators to supply AC power. In order to supply a constant frequency the speed of the generator is held constant by the CSD while engine RPM varies from idle to max RPM.

a hydraulic unit could handle the extra power. If a variable pump of sufficent capacity were installed the engine performance could be increased until the structural limitations of either the engine or other parts of the drivetrain were met.

however a hydraulic unit as I mention would cost nearly as much as an entire car does today, unless advances in technology and production allowed manufacturing costs to be reduced.

cogs, belts, where have you guys been, thats old news, that technology dates to the 20s.

were past that, I want to see electronically controlled hydraulic units, coupled to a small gas turbine engine. IIRC a turbine engine the size of a sewing machine that weighs 150 pounds can produce up to 250 SHP, and coupled to a gear reduction unit to bring the 40,000RPM+ down to a more acceptable level, were talking over 250 lb/ft and if properly tuned could compete in economy with todays piston engines.

they can use anything from gasoline to salad oil for fuel as well. You could go to your local grocery store and fill up on crisco.

I'm not sure I would want a 40,000 rpm sidewinder turbine shaft spinning three feet in front of my little body...unless the car came with a 700 pound Kevlar scattershield....

then you'd loose you power to weight ratio

I haven't been anywhere near a CSD for one, and two I only offered that the drive unit had the same function, i.e. "like that of a go-cart transmission". I have no idea how Audi actually does it.
Thanks for educating me on it though.

warmonger

Ford Press Release: sorry I had to post the whole thing, I'm not sure that the link will work again!
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FORD, EPA TO DEVELOP PROMISING HIGH-EFFICIENCY AUTOMOTIVE POWERTRAIN

WASHINGTON, D.C., October 12, 2001 – Ford Motor Company and the U.S. Environmental Protection Agency announced today a cooperative effort to develop a unique high-efficiency “hydraulic hybrid” automotive powertrain. The technology to be developed and tested under this agreement has the potential to significantly improve the fuel economy of light-duty trucks and sport utility vehicles (SUVs), which could reduce U.S. dependence on imported oil, reduce greenhouse gas emissions and save consumers money at the pump. The agreement is the first of its kind between an automaker and EPA.


In this agreement, Ford has committed to invest to further develop this proprietary technology, with an aim toward putting a pilot fleet of vehicles on the road by the end of the decade.


The basic technology was originally developed and patented by EPA's National Vehicle and Fuel Emissions Laboratory in Ann Arbor, Michigan, and refined under a previous cooperative agreement with Ford. The advanced powertrain features a high-efficiency engine and a unique hydraulic hybrid propulsion system. The hydraulic hybrid system uses hydraulic motor/pumps and hydraulic accumulators to store energy, in the place of electric motor/generators and batteries used in electrical hybrid drive trains. Like other hybrid systems, energy saved via regenerative braking is used to help power the vehicle. This hydraulic power system could have cost and power advantages over electric hybrid systems.


The hydraulic hybrid research project complements Ford Motor Company's commitment to develop and implement technologies providing high-volume solutions to address societal concerns, said William Clay Ford Jr., Ford Motor Company chairman. “While we are working hard to implement proven technologies on our vehicles today, we must at the same time push forward with advanced research that holds a bright promise for tomorrow,” he said.


“Recognizing that significant hurdles remain in development and prove-out, hydraulic hybrid technology holds great promise for our customers and for our society,” said Gerhard Schmidt, Ford Motor Company vice president – Research.


"This is the first-ever cooperative agreement with an automobile company targeted to develop EPA-patented automotive technology," said EPA Administrator Christie Whitman. "I am very excited about the potential for this technology to make a major and cost-effective contribution toward achieving the President's long-term energy and environmental goals. This is a very good example of a public/private partnership working to help consumers and to benefit the environment."


Ford and EPA will be working with FEV, one of the world's leading advanced automotive engine and powertrain research and development firms, and Eaton, a major Tier 1 supplier to the worldwide auto industry, to build and test the new technology with the goal of integrating it into future products.