Gear Ratio Ranges of two different CVT's

[coachgeo]

Being a bit dense myself; Im curious what smarter minds than mine say about two different ratios. Which is better and why etc.


........Start Ratio... to .... Final/Top Ratio
A...... 3:1 ............ to .......... 0.5:1
B...... 3.1:1 ......... to .......... 0.8:1

[TnFan]

CVT situation "A" gives the widest ratio ....In my way of thinking should be the best.
Diesels need lots of gears to use their torque band effectively.
The rear sprocket ratio should be able to adjust for size of engine and max speed.
Question is if tuning of the CVT to the diesel RPM range is possible with available springs and weights.
Another question is if the CVT "progression ramp" favors a gasoline engine torque curve or a diesel
engine torque curve or is simply a linear progression. Then there is the question of the type of driving
to be expected ..... mountain driving, flat land driving ..... city driving. All of which are almost impossible
questions. I guess a person just has to experiment and find what works best for them.
I'd love to see a "manually operated" CVT and clutch where the operator could adjust while driving.
I wonder if a computer controlled CVT would be possible.
Just my opinion..... I have no practical experience.
TnFan

[coachgeo]

CVT situation "A" gives the widest ratio ......TnFan

How much different in real life sense is the final ratio of 0.5:1 and 0.8:1 with a diesel in mind?.

[BertTrack]

How much different in real life sense is the final ratio of 0.5:1 and 0.8:1 with a diesel in mind?.

Assuming not changing the final/pre ratio:

Using A as a baseline your minimal speed with c.v.t. engaged is 5mph @ 1000rpm

3:1 @ 1000rpm @ 5mph || 0.5:1 @ 1000rpm = 30mph || 3:1 @ 2000rpm = 10mph || 0.5:1 @ 2000rpm = 60mph || same @ 3000rpm = 90mph

B would be:

3.1:1 @ 1000rpm = 4.8mph || 0.8:1 @ 1000rpm 18.6mph || 3.1:1 @ 2000rpm = 9.6mph || 0.8:1 @ 2000rpm = 33.2mph || same @ 3000rpm = 49.8mph

Makes sence. Since the A variety is almost half as long. Speed is almost double.

I'd pick the widest ratio. And adjust the overall ratio when needed.

Set it up to begin shifting at the rpm where the engine is most efficient. Depending on the specific brake fuel consumption diagram.

[tappy]

I totally agree with Bert..
Only other thing to note is that CVTs are most efficient when operating between 0.8:1 and 1:0.8. When outside this they tend to be slightly less efficient, but I'd expect that to be offset by keeping the engine revs low for a given cruising speed