angerball

CVT supposedly has no gear, which translates to a smooth acceleration with no shifts...then my question is, how does the tachometer needle operate...???

docjan_uk

rather than talk of the tachometer, Ill just say how it operates, the revs go up as the car accelerates, and then shift back down when it gets up to speed.

Depending on the style youre driving, itll vary how high it revs before settling down to whatever engine speed is appropriate for that speed.

The CVT allows the engine to always be in the perfect power band, meaning its always in the sportiest mode and in economy, using the minimum amount of fuel neccesary to do exactly what you ask of it.

Basically, the needle goes up and then goes down as the car settles into its cruising speed.

JoshS

You mean, how does the engine behave while you accelerate?

It's not that a CVT has NO gears, it has an infinite number of gears. Think of it as an analog transmission (where most transmissions are digital).

If you hold the pedal in a constant position as you accelerate, then the tach stays at a fixed position as you accelerate (the transmission continuously and constantly adjusts the ratio as you accelerate, rather than doing it just a small number of times as in a regular automatic).

Josh

k4ls

Sort of. If you push the accelerator down lightly and slowly then you are telling the car that you do not want to get to speed quickly. This would be equivalent to an economy mode. Thus the Tach will not jump in RPM, stay at a lower and RPM increasing slightly to get you to speed. On the other hand if you press the accellerator down hard and fast then your are telling the car you want to get to speed rigt now, thus the tach jumps to the most efficient RPMs to get you to the speed that your foot told the accellerator. Once that speed is achieved as docjan_uk explained the car is at cruising speed and the most efficient RPM level is adjusted. The tach, from an accelleration standpoint goes as your foot goes. If pressed hard it jumps and stays at the tach level until speed is reached, if pressed slowly and smoothly it stays in an economy mode and uses the most efficient means of getting to speed with the tach increasing slowly. All methods of accellerating in between vary depending on your foot.