08' 2WD Chevy Tahoe Hybrid Review by LeftLanenews

[MechEng]

Originally Posted by eurohazard

I tried clicking the link before, but swear something else came up....but it works now. It's a very good read.

1) Can you make any sense of this statement?..."Not only that, but it is MORE ADVANCED THAN THE PRIUS' eCVT, since it overcomes the Prius' requirement for higher speed motors for highway driving speeds, AND the consequantial Prius' compromises necessary for highway speed operation."

2) The article was good........but that's talking about an inferior (according to rob) product. How does GM's 4 gears play into how their system works?

p.s. If it appears I was spreading false information......and that's not my intent (you guys may or may not know that).

I'll take a crack at it.

1. The Prius eCVT is basically an eCVT with one fixed gear ratio. The GM system has 4 fixed gear ratios.

2. The added fixed gear ratios allow the engine to sit in a more efficient RPM range longer and over a wider range of speeds and situations. The electric motors assist the engine between gear shifts to keep the RPM of the engine fairly consistant (hence the eCVT).

[HEVguy]

Originally Posted by MechEng

I'll take a crack at it.

1. The Prius eCVT is basically an eCVT with one fixed gear ratio. The GM system has 4 fixed gear ratios.

2. The added fixed gear ratios allow the engine to sit in a more efficient RPM range longer and over a wider range of speeds and situations. The electric motors assist the engine between gear shifts to keep the RPM of the engine fairly consistant (hence the eCVT).

Well put MechEng, you kept it simple, but explained the jist of it. Considering the general audience doesn't have an engineering degree, I wouldn't add much of anything to your definition. Maybe only augment the last sentence a bit:

The electric motors assist the engine between gear shifts to keep the RPM of the engine fairly consistant during the vehicles varying speed/torque requirements (hence the eCVT).

[eurohazard]

Originally Posted by HEVguy

The electric motors assist the engine between gear shifts to keep the RPM of the engine fairly consistant during the vehicles varying speed/torque requirements (hence the eCVT).

Oh snap! Did you just say "gear shifts"? A real CVT doesn't shift gears, correct?

So, the GM unit uses 4 forward gears (we have established this much). The electric motors work at all speeds, between all 4 gears, and do like you say....basically fancy rev matching?

[chevydlrmn]

Originally Posted by Squashman

I have a 2WD Yukon hybrid. Over my first 2100 miles, I averaged 21.9 mpg. On the highway cruising at 60-65, I usually get 24-25 mpg. Truthfully, I don't care if it has 4 sp, 6 sp, or 21 speed like my bike. I just know my Yukon's mileage is as good as my wife's 4 door sedan with a 5 speed auto.

On a side note, the vehicle is unbelievably quiet.

Thank you for the comment, and welcome!

This system needs to be appreciated for what it is.

I drove one today on a 60 mile round trip. Traffic, stop and go, and cruising. I accelerated to 35 in electric only, observed mostly 24 to 26 mpg's cruising around 64mph.

My 70 year old passenger commented on how quiet it is as well.

[eurohazard]

Anyone else own or drive one of the GMT-900 Hybrids?