Hello everyone,
How long have you seen your Tahoe in Hybrid mode, both low speed and high.

 

do you mean electric only? its all about speed under 30 it will run on electrics for quite a while...on the highway at 85 it will be in v8 or v4 mode depending on your right foot and the electric will assist at that speed in v4 mode

 

Thanks Jet 1 for the information,
What I am talking about is when you look at your navigation computer in Hybrid mode you will see when the truck is under HYBRID MODE with both the engine and electric motors operating. During a trip how often do you see this? On my last 650 mile trip this occured 55% of the time.
Kind Regards Ken

 

I rarely see them both running together in "Hybird" mode. Couple of things though, first I don't usually have the Hybrid screen up on the monitor and second I don't do much long distance travel (it's less than 4 miles from my house to the office).

 

Good Morning CPMS,
Could you have a look for me on one of your shorter drives, just to see how long you are in Hybrid Mode. I will try one today.
Kind Regards Ken

 

in hybrid mode [v8 and v4] about 70% of the trip

 

Ken, sorry I didn't respond sooner. I rarely see the truck in Hybrid mode (ICE and EV at the same time). I've only noticed that happen during semi heavy acceleration and at certain freeway speeds (which I rarely do). I've done a little un-scientific checking and it looks like I'm in EV mode probably 20-25% on average. In the city, the truck will begin to accelerate from a red light in EV but quickly bring the ICE on at around 10-12 mph. Only way I can get it to do better is to accelerate very slowly (irritating others in the process). It can drop back into EV after running at 20-25 mph for a while but by then I usually hit another traffic light. I'm going to try and experiment with not running the AC for a full tank once the weather outside gets a little cooler. I assume not running the electric motor for the AC compressor will help to decrease load on the batteries and result in longer EV running.

 

Good Morning CPMS,
This is what I experienced when I completed short distance less frequent travel. Completly a different truck when you do long distance travel which I believe results in higher battery capacity.

 

To ALL: also watch the DIC for V8/V4 and your instant fuel economy too. Both the nav display and the DIC have some filtered time delays but with your observation skills you will soon learn more about your vehicles behavior.

For instance on a certian down hill grade on I-75 north of ******* MI, I can run V4 @ 99 mpg (DIC) at posted speed (70 mph). What is going on is that the ICE is in fuel cut off. By staying in four cylinder mode the catylitic converters stay hot longer. (I will come back to the hot converters) The battery is providing some power to overcome aero drag even on the down hill. So I can't stay in this mode forever. Steeper grades will allow some charging.

By light footing I can stay in this mode about a half mile. My goal is 3/4 mile.

In the mountians out west the vehicle stays in V4 fuel off for much longer with the fuel off. The battery fills up too. Once the battery is full where do you put the power? Another day....

Now about the hot converters. Regular vehicles stay in V8 pumping cool air through the exhaust. This cools the cats fast and the engine actually has to re-fuel to heat them back up. Cold cats are bad for emissions. Your hybrids deactivate half of the cylinders and then the camshaft phaser further reduces the volume of cool air pumped over the cats.

Anyone doing Rocky Mountian driving will notice very low instant fuel economy going up but these things recover real well going back down. The recovery is a result of the cats staying hot much longer and no need to feed them fuel that does no work in propelling the vehicle.

The Eisenhower Tunnel down to Georgetown is a cool place to hypermile by watching the DIC and display. The round trip fuel economy up Mount Evans is another. Going up to 14,100 ft the instant FE looks bad but the long term average down completing the round trip is impressive. Hence the term "recovery".