Toyota's New CVT Has A Launch Gear

"WEBVTTKind: captionsLanguage: enHello everyone and welcome!So you're thinking to yourself, I want a sports car and so you head to the Toyota dealership.Well, they don't sell a lot of sports cars so that doesn't make all that much sense, but now you're sayingI want a sports car with a CVT.I don't really get you butToyota has something for you a CVT with a launch gear was it for the performance oriented folks that also likeCVTs. Not exactly so in this video I'm going to be talking aboutToyota's direct-shift CVT which is a CVT and it does have a specific gear just for accelerating from a stop,but it's not for performance reasons like it may sound Toyota CVT with a launch gear instead it is for efficiency.So how does this all work?Well if you look at a CVTand you look at its gear ratioversus its efficiency curve so when it's on the extreme ends of that gear ratio when it forces one of the ends of that pulleyto be at a super narrow radius for that belt to go around then it's not super efficient in that range ideallyit's somewhere in the middle where both pulleyshave a nice even large radius for that belt to go around and it's going to be in a happyefficient range and as you get to the extremesmeaning if you're at a very low speed and you're requesting a very high gear ratioor if you're at a very high speed and you're requesting a very low gear ratiothen what's going to happen is you're going to be in an inefficient range of thatCVT. While inefficient is bad of course and especially of course when you areToyota and so they made an adjustment for this so instead ofpreviously where they had to have aCVT range that accommodated high gear ratios with low vehicle speeds and high vehicle speeds with low gear ratios theyinstead shift the CVT to operate and arrange for higher vehicle speeds and lower gear ratios and allow a direct gear to take care ofthose high gear ratio scenarios where you're accelerating from a stop and a direct gear is of course a very efficient way of transmitting powerbecause you know there's not losses that are associated like going through a beltso a very efficient method for low speed range and then switching over when you're drivingyou know normal driving conditions at those higher vehicle speedsyou're now operating in a more efficient range whereas before you know you had to sacrificekind of somewhere in the middle in order to be efficient in eitherend so you've got a launch gear for low speed efficiency and you've got a CVT for high speed transmission efficiencyand there actually is a performance benefit to this so when you'reaccelerating from a stop by having that more aggressive direct gear ratio you actually get a better response and better launchacceleration so just kind of showing a simple curve here accelerationversus time a little bit greater accelerationand that response comes a bit sooner by using a direct gear rather than a CVTsome people don't like the kind of spongy response that CVTs have which is kind of eliminatedthrough the use of this direct gear from starts next we getinto the belt angle used by the pulleys and this is actually narrowerso it's gone down from 11 degrees to 9 degreesso why were they able to reduce that belt angle well essentially this is because either removing the responsibility of launching the carfrom a dead stop and by removing that responsibility where the acceleration load is very highand the torque transmitted through that CVT is very high from that initial accelerationyou're able to use a smaller CVT and a narrower belt because it's no longerresponsible for that really high torque application where you're initiallyaccelerating the vehicle so it's smaller it's narrower and as a result of having that narrower angleyou're able to improve the shift speed so 20%faster shift speed and that's simply because the pulleys don't have to move in and out quite as much inorder for it to change the gear ratio as much soit's the same amount of movement will change how much the gear ratio has changed more and finally I want to talk aboutgear ratios because there's two kind of interesting facts aboutCVTs first of all is most people don't like driving CVT's they say they don't like the way it feelsthe second thing is most people don't really know what they're drivingyou know there's a lot of car enthusiasts out therebut we're not the majority of humans so most humans they get in a car. They don't really carewhat's going on underneath, they don't know what's going on underneath the hoodthey just know what they like and what they don't like and what humans tend to like is the monotonous dullexcitement that comes from an automatic transmission where it shifts gearsthey'd like to have those gear shifts, soCVT engineers have decided you know what we can make you feel like you're driving a regular old boringautomatic when in fact you're driving a rather exciting CVTand so what happens is let's say you floor it in this Toyota using this CVT wellit'll start in that launch gear and it'll start your accelerationgoing up to your max rpmthen it will drop down a gear ratio, and it will switch over to the CVT beltand then it will be in it's you know it's its most aggressive gear ratio that that CVT belt allowsso on the low end of thatCVT when you finally reach peak rpm you of course have to switch to a lower gear ratio and instead of just a continuous smoothyou know remain at peak horsepowerwhich would be ideal for acceleration instead it creates stepswithin the CVT so you have set gear ratios that it maintainsso it'll drop down to a lower gear ratio keep accelerating up until peak rpm drop down into a lower gear ratio keepaccelerating up and so on as you continue if you've got your flooryou know if you've got your foot to the floor and you're asking for max acceleration if you don't get it too much throttleit's just gonna put it in an efficient rpm, and you know you're not going to really have those gearshift sensationsbut you're not going to notice it either because you're barely giving it any throttle and in regular automaticsyou know if you're giving it extremely light throttle you really aren't going to notice significant. You know feelfrom that gear shift so from a CVT it can just put it in an efficient rpmlet it just sit there let the engine sit there and adjust the belt as necessary as your vehicle speed increases andso this is a silly thing that's done because humans don't like CVTsthey like the sensation of gear shift when in reality the faster thing to do would just put it at peak horsepowerwhen you floor it and leave the gear ratioconstantly adjusting so that it maintains peak horsepower as you go across whatever RPM is peak horsepowerjust keep the the gearing to just constantly to allow for that constant rpm of peak horsepowerbut that's not what humans like so engineers put in silly things like this to make you guys happynot you guys, but you know the folks that drive CVTs, soultimately CVTs are cool. I think they're bettertransmissions than most of the automatic transmissions that are out therepeople don't like it when I say that but I've driven a lot of vehicles, and I think truthfullyautomatics a lot of them out there feel terrible there happens to be an 8-speed ZF transmissionthat's amazing and it's getting put in everything now, and it's a great transmissionbut there are also very good CVTs out there from a you know feel perspectiveI think they've gotten a lot better than what they used to be and I think it's cool that Toyota has introduced this launch gearinto one of their transmissions, it'll be interesting to try out so thank you all for watchingand if you have any questions or comments of course feel free to leave those below.\n"