Many hybrid-car owners buy once -- but not again

[RedylC94]

Originally Posted by WriConsult

-- with the Honda hybrids when you stomp on it there is a whole lot of revving and not a lot of GO. With all that noise you'd think you'd get the same kind of torque multiplication that you do by slipping the clutch in an MT. .

As I understand, you get exactly the same torque multiplication from the Honda CVT clutch that you do from the clutch with a conventional manual, i.e., none at all. In both cases, all the torque multiplication comes from the rest of the transmission.

[WriConsult]

Originally Posted by RedylC94

As I understand, you get exactly the same torque multiplication from the Honda CVT clutch that you do from the clutch with a conventional manual, i.e., none at all. In both cases, all the torque multiplication comes from the rest of the transmission.

If that hypothesis is correct, why is it that an MT can leap off the line when you slip the clutch, and in a similarly powered CVT it's like molasses dripping out of a chilled bottle?

[lightfoot]

Originally Posted by WriConsult

If that hypothesis is correct, why is it that an MT can leap off the line when you slip the clutch, and in a similarly powered CVT it's like molasses dripping out of a chilled bottle?

I think it has to do with how the CVT is "mapped" to select gear ratios. I had the exact same issue with a Dodge Caliber CVT I drove a few years ago. Obviously with MT YOU select the gear ratio so you have control over the amount of torque/acceleration under different conditions rather than having the ratio selected by the CVT's control unit.

IOW, I don't think it's a specific Honda issue. The HSD "CVT" is structured differently - it's actually called an eCVT - and so behaves better.

[ItsNotAboutTheMoney]

Originally Posted by lightfoot

I think it has to do with how the CVT is "mapped" to select gear ratios. I had the exact same issue with a Dodge Caliber CVT I drove a few years ago. Obviously with MT YOU select the gear ratio so you have control over the amount of torque/acceleration under different conditions rather than having the ratio selected by the CVT's control unit.

IOW, I don't think it's a specific Honda issue. The HSD "CVT" is structured differently - it's actually called an eCVT - and so behaves better.

I thought it was a combination of slow gear selection and transmission inefficiencies.

I wish they'd stop calling the Prius' power-split an eCVT, it just confuses things. Planetary Hybrid Transmission. Little Box Of Happiness. Anything that emphasizes that it's different would do.

[lightfoot]

Originally Posted by ItsNotAboutTheMoney

I thought it was a combination of slow gear selection and transmission inefficiencies..

The Caliber "shifted" quickly enough, it just chose gear ratios I didn't want at the time.

Originally Posted by ItsNotAboutTheMoney

I wish they'd stop calling the Prius' power-split an eCVT, it just confuses things. Planetary Hybrid Transmission. Little Box Of Happiness. Anything that emphasizes that it's different would do.

"Little Box of Happiness" is perfect. Maybe it should be a cleanmpg acronym "LBOH"???

[WriConsult]

I agree, the HSD's system is fundamentally different from ALL the other transmissions we're used to - whether MT, slushbox, DSG or mechanical CVT -- to just put that little "e" on the front of one of those is misleading, and an insult to the clever, elegant design that is the little box of happiness.

[all_about_the_glide]

Buying new today the garage would contain a C and a V. But I'm not, so I'll dream...a lightly used C-Max as well as a cherry used V are definately in the running to replace the SAAB wagon when it hits the point of throwing good money after bad. Buying a V for work is under heavy consideration...if I had fiat I'd be at the dealer right now.

[herm]

Originally Posted by WriConsult

If that hypothesis is correct, why is it that an MT can leap off the line when you slip the clutch, and in a similarly powered CVT it's like molasses dripping out of a chilled bottle?

Conservation of momentum in the fast spinning engine and flywheel.. there is no torque multiplication in a manual clutch.

[WriConsult]

OK, sorry to throw us off on a semantic tangent by saying "torque multiplication." Sheesh, obviously I used the wrong term, and sorry that caused my POINT to be missed.

I guess I don't know what the terminology is for the difference between an MT car and a Honda CVT, but it's there. Slip the clutch on an MT so that, for instance, the engine holds 3000rpm as you take off ... and you LAUNCH off the line. Floor a Honda hybrid and the engine darn near just the same, but the car takes its sweet time building speed. With the engine revving like that it ought to be developing plenty of power, but a scary chunk of it isn't going to the wheels ... and that makes me nervous about what's happening inside the transmission. You engineer types, feel free to tell me the appropriate LABEL for this difference (since, to split hairs, it's apparently not "torque multiplication").

[ItsNotAboutTheMoney]

Originally Posted by WriConsult

OK, sorry to throw us off on a semantic tangent by saying "torque multiplication." Sheesh, obviously I used the wrong term, and sorry that caused my POINT to be missed.

I guess I don't know what the terminology is for the difference between an MT car and a Honda CVT, but it's there. Slip the clutch on an MT so that, for instance, the engine holds 3000rpm as you take off ... and you LAUNCH off the line. Floor a Honda hybrid and the engine darn near just the same, but the car takes its sweet time building speed. With the engine revving like that it ought to be developing plenty of power, but a scary chunk of it isn't going to the wheels ... and that makes me nervous about what's happening inside the transmission. You engineer types, feel free to tell me the appropriate LABEL for this difference (since, to split hairs, it's apparently not "torque multiplication").

OK, I'm not an engineer, but I think I get it. It's not multiplying torque, it's allowing increased engine rpm. The normal hard connection in an MT prevents the engine from spinning freely so rpm has to build gradually. The difference between 0 and idle is simply too great to allow you to start moving without the clutch. Slipping the clutch gives enough friction to make the wheels move, but enough slip to allow the engine to spin more freely, like in a slushbox. But, the different mechanism and the manual clutch control allows the driver to make that baby fly.

The only problem is that the 3000 rpm engine is creating a lot of friction. So, your flying baby is liable to suffer some harm. Primarily, I guess, you'll wear out the clutch.

In normal driving you want to release the clutch smoothly and as quickly as possible for reduced wear and high efficiency. Like locking the torque converter, I guess.