Why The Lexus Toyota CVT System sounds Harsh on Hard Acceleration

[Marlinleg]

 

Hello to one and all. The motoring press always comment on the harsh engine noise when accelerating hard in a Lexus/ Toyota Hybrid. I now know why. Link below to a YouTuber who tested  a Toyota RAV4 PHEV 3 Months Then followed up with a second review of the car saying"i was wrong here's why, well done Toyota very clever"

Speaking with a Toyota guy who's just returned from a course in Derby Toyota are looking to the future 

Toyota hydrogen fuel cell car arrive home plug in your Toyota hydrogen fuel cell car to power your house on the spare energy. Please don't ask it's beyond me  the link below 

 

https://youtu.be/X_CxHjK1Cn4

 

 

[Al D-Much]

Funny as my 2020 NX doesn't sound harsh, you can hear the engine rev up, the progress is swifter (especially in sports mode and using the paddle shifters) sounds quite mean to me, I like the noise, sounds sporty.

I had a Mitsubishi CVT, which had the "elastic band" drone before any acceleration, almost like a CVT version of turbo lag in an old Saab 99.

[Las Palmas]

I do not know which terrain the bad reviews of the sound of CVT (and hybrid cars) come from, but living here where mountains are norm, I am sorry to admit that sound of the Lexus CT is not the most pleasing when climbing and pressing the engine real hard.

Now the CT is not a performance car and if it is not being used as if it was it does not make any more noise than cars with other kind of engines.

That Lexus  (and all other car factories) lie about how little fuel is needed to drive a certain distance do not make the quality of the any smaller. It make the trustworthiness of car factories and those accepting these values worth nothing, but business is business and us suckers that believe in the factories are - well what we are. Those of us that claim it is possible to get the mileage / distance / fuel is like the factories tell us are like those that believe that the best of what the EV  factories claim their cars can drive before needing to be recharged.

[Deathstar]

The thing that you have to remember is this... when reviewers look at the car, they typically thrash them around a race track, and complete lots of standing starts etc; that's not how I drive. 

I drive normally, from 0 - 20, then 20-30 or 50-70 on the motorway. The CVT is excellent for that. The CVT is great for smooth driving. My wife has a VW Tiguan with the DSG box. It's smooth, however the CVT is smoother. The DSG gets flustered at a roundabout. If you creep forward in the VW, it will change to second gear, then if you need to go quickly, it will try and spool the turbo up try to move, realise it can't get off quickly and then change down. We have been caught out a few times like this, meanwhile the CVT just works. 

[Zotto]

A difference I noticed in eCVT from GS300h to RX 450h is the engine V6 sound, quite  better to hear revving in proper range.

[javadude]

I found no problem with my RX, perhaps the engine noise nicely masked the CVT. My NX sounded awful when reved with that 4 cylinder engine though. I don't know how much was the engine and how much the CVT but it was just embarrasing. Apart from the the car was awesome though.

 

[Bluemarlin]

Same.  I haven't noticed it at all in my RX.

[Thackeray]

8 hours ago, javadude said:

perhaps the engine noise nicely masked the CVT. My NX sounded awful when reved with that 4 cylinder engine though. I don't know how much was the engine and how much the CVT

I doubt that the CVT transmission actually makes much noise apart from the usual noise you get from electric motors. If the engine is not running, I expect the CVT with its two electric motors would produce a similar noise to an electric car.

When journalists talk about noise from the CVT I think what they're talking about is the engine noise. That's because the CVT allows the engine to spin up to maximum power which for most petrol engines can be quite noisy. Conventional transmissions don't allow this unless you change to the lowest possible gear.

[Harrier Man]

I think it is important to understand some history here. Older CVT systems used cones and belts which were 'whiny'. Many reporters still hold onto this view. However, what we are talking about here is an eCVT and this is very, very different; as Marinleg reported in his first post - once the reporter had looked at in more detail, he changed his mind for his second review.

The YouTube reporter in question made reference to a detailed examination by a university lecturer at, I think Weber University. His video is well worth watching. Not a cone or belt in sight; it's all planetary gears and electric motors. As a transmission system it will have a certain level of noise in its own right but also the Toyota system is designed to keep the combustion engine in an efficient operating range. That range is at higher revs than one might normally expect for a given speed and this contributes some additional noise to the system. Whether you describe this as harsh depends on your experience and point of view but personally, I think of it as different, not harsh, and Lexus have done a good job to give us a quiet and very efficient vehicle. 

[Hillie]

I found this to be a good video on 'How an eCVT works' 

https://youtu.be/izdMsVOo7bU

A mechanic performs a very fast teardown a Toyota Prius eCVT and then gets into a detailed explanation of the Hybrid Drive and Generation system works including the selection of drive ratios.  It is the 2nd of a two part video. Part 1 details can be found inside the link.

 

 

[Ala Larj]

Fascinating. Although I do feel sorry for his wife!

[Hillie]

On 8/6/2022 at 9:08 PM, Harrier Man said:

I think it is important to understand some history here. Older CVT systems used cones and belts which were 'whiny'. Many reporters still hold onto this view. However, what we are talking about here is an eCVT and this is very, very different; as Marinleg reported in his first post - once the reporter had looked at in more detail, he changed his mind for his second review.

The YouTube reporter in question made reference to a detailed examination by a university lecturer at, I think Weber University. His video is well worth watching. Not a cone or belt in sight; it's all planetary gears and electric motors. As a transmission system it will have a certain level of noise in its own right but also the Toyota system is designed to keep the combustion engine in an efficient operating range. That range is at higher revs than one might normally expect for a given speed and this contributes some additional noise to the system. Whether you describe this as harsh depends on your experience and point of view but personally, I think of it as different, not harsh, and Lexus have done a good job to give us a quiet and very efficient vehicle. 

@Harrier Man  Could this the Weber University Video you mention in your post?

https://youtu.be/O61WihMRdjM

The amount of engineering used in these things is astonishing.

 

[Harrier Man]

7 hours ago, Hillie said:

@Harrier Man  Could this the Weber University Video you mention in your post?

https://youtu.be/O61WihMRdjM

The amount of engineering used in these things is astonishing.

 

Hi, yes that's the video I was referring to. Thank you for finding and posting the link.