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CVT Simulation

Discussion in 'Racer' started by 2o6, Jul 27, 2010.

  1. 2o6


    I don't know anything about script writing, but how well does RACER cope with real time text edits? I wonder how hard would it be to write a script that varies gear ratios proportional to acceleration demand? Granted, we don't have a torque converter to work with, but we would be simulating CVT's on their most basic level.

    How would this even be accomplished?
  2. I don't know, but have wanted to make stall converters for some of my hot rods...to simulate the real cars that have them. Anyone know how to do that?
    I wonder if the CVT you mention can be used like the IRL cars Honda Element, and Nissan Rogue (cars like them-similar to these..:) ). That is if anyone models/converts them....??
  3. Well, interesting problem. I have thought about it... So CVT is for having only "one" gear for the whole speed interval. It is like you put the gear lever into top gear and try to accelerate to the top speed. At lower speeds, it would be funny, and perhaps it stalls. During the work of a CVT trans, it looks like it starts in first gear, and after reaching an rpm it the cvt start to lower the ratio from a higher value to a lower value with the rpm is constant. The quickness of the variation depends of something, maybe the torque we get on the powered wheels (which is measurable),maybe the speed. I am not a program designer, but maybe possible, to make a very beta thing. It is almost the same, like autoclutch. If you give a little amount of throttle, the autoclutch works slowly, but if you kick the gas, it works guicker. At the autoclucth, the controlling value is the rpm, to keep the rpm between idle and autoclutch rpm while the autoclutch is working. At the CVT, it would be almost the same. When it reached the rpm when the CVT have to start working, then it has to varies the gear ratio to keep the rpm constant. So my amateur idea is to set the rpm, when the CVT starts to work. This rpm will be that rpm, which the CVT tries to keep constant during its working. Then we give the starting and the ending ratio. After the value of the ratio reached the ending ratio, the CVT finish its duty.
  4. BMWspain's Prius INI faked a CVT with a single gear.

    Not many cars have CVTs so I don't expect to see Racer support for it any time. We don't even have proper automatic yet.
  5. 2o6


    ^^ Pretty much all of Nissan's current lineup uses a CVT instead of a traditional Automatic.

    The Prius CVT doesn't really count. He pretty much made the Prius into an electric car and used a 1-speed direct drive gearbox.
  6. Well yes, it has only one gear + a fixed end ratio. It can be used in the Prius because of the high torque of the electric engine. But at low speed/RPM a petrol engine has "low" torque, so the acceleration from low speed would be last for ages... I think, we should mention the cvt idea to Ruud.
  7. I tried to fake a CVT in my W20 saloon but i ended up having to give it more power and limit the top speed with traction control in order to make it more realistic(ish).

    I also tried doing a CVT for another car. I used a slippy clutch and 3 almost seamlessly shifting gears which, under hard acceleration, you can`t really feel.

    Added a link to the car in case anyone is interested:
  8. This is one of the smartest Racer physics hacks I've seen. Good work.