First, I object that you want to talk about "ideal" CVTs.

In the case of "ideal" CVTs, I'd choose (1) and that's what you'd lead me to do.

However, let me retort now: With a real CVT, doing 0-60, would you do any/both of the following?

(a) Rev the engine to 6000 rpm from the rest and let the CVT engage its clutch mechanism (which will be slipping).
(b) Keep the engine at 6000 rpm all the way up to 60 mph, with whatever amount of clutch slipping that's necessary.

Keep in mind, that a real CVT has a lowest ratio that probably cannot sustain an engine speed of 6000 rpm at a slow car speed of 5 mph. Therefore the clutch must be slipping if you want 6000 rpm. Also keep in mind, that when the clutch is slipping, it cannot transmit as much power as it can when closed. This is simple physics: static friction coefficient is higher than slipping friction coefficient, plus slippage causes heat loss.

Now suppose the engine makes slightly lower power, but still substantial, at 5000 rpm, and the clutch can indeed close at 5000. Will you now insist to take the slippage power loss all the way up to 6000 rpm? Well, the answer depends on how much power is available at 5000, doesn't it? That's where the shape of the power CURVE comes into play.

In my proof, I argue that as long as there is a definite slippage power loss, and the power curve is locally flat (i.e. doesn't have a spike) at 6000 rpm, then the ideal rpm to be in, at an instant, is always lower than 6000 rpm, to close the clutch. Now this is definitely not the only reason you may want to run the engine at lower than peak-power rpm, but it's one that's simple to deomonstrate mathematically.

Hope this lets you understand my proof.

所有跟帖： 

• 理想的CVT是... -TBz- ♂ (1402 bytes) () 09/19/2006 postreply 00:30:08

• OK, you admit this: 在起步的瞬间离合器打滑是不可避免的 -Speculator- ♂ (3096 bytes) () 09/19/2006 postreply 05:57:19

• OK, but.. -TBz- ♂ (743 bytes) () 09/19/2006 postreply 09:02:02

• Understood. -Speculator- ♂ (442 bytes) () 09/19/2006 postreply 09:16:41

• Partially agree -TBz- ♂ (641 bytes) () 09/19/2006 postreply 11:48:12

• Sorry, -Speculator- ♂ (465 bytes) () 09/19/2006 postreply 12:11:54

• Note that I didn't say: "现有汽车上使用的CVT，(根据你的贴子)在有 -Speculator- ♂ (822 bytes) () 09/19/2006 postreply 07:01:05