Engine RPM at 70 mph for Hybrid

[El Kabong]

Get a ScanGauge3

Or any compatible OBDII dongle and some software for a phone. The ScanGauge is a bit pricey though it's a nice tool.

hybrid transmission has no gears

It certainly does have gears in it, how do you think the power gets moved around between the ICE, two electric motor-generators, and differential in there? My post above was about how the gearing in the hybrid has no fixed input-to-output ratios. Have a look:

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[sanpablo]

The hybrid transmission has no gears. The hybrid does not come with a tachometer. I think you can still get the gas engine rpms somehow.

Yes with ETA, Engineering test mode. You can call up RPM.

 

[FredsMaverick]

Sorry I meant it has no gear shifts like a traditional automatic transmission.

 

[El Kabong]

Yes with ETA, Engineering test mode. You can call up RPM.

How-to enable this?

 

[inline_five]

2023 hybrid FWD

70 mph - 2000 RPM
75 mph - 2200 RPM

+/- because generating more power will increase RPM.

 

[FredsMaverick]

Thank you for the information! Now I need someone with a 25 or 26 to post their rpms.

 

[HeyBales]

More pre-25MY.

ICE & TM & GM RPM / 100 so it fits on graph with speed.
Got it up to 4000 RPM doing a fast speed increase from 60 to 78 at the end.
Made the Generator Motor come out of opposite spin to lay down that power!
Got up to ICE 150.5 and TM 39.7 ft/lbs tq.
Data file attached if curious.

 

[Grabber Rick]

I am (easily) confused.

The hybrid eCVT does not directly connect the engine to the final drive like an automatic which has locked it's torque converter or a manual gearbox. It is instead connected through a planetary gearset and so does not have a fixed drive ratio (of course, with AWD the PTU and rear diff have fixed ratios).

So I would think that the engine RPM is not directly linked to the speed of the vehicle - if for example you are doing 65MPH on level ground and the vehicle is operating in hybrid mode, then transition to a downhill slope, the amount of power demand should decrease, allowing the engine to slow its RPMs or even to shut off as the system goes into regenerative mode. Likewise if you are doing 65MPH on level ground and the vehicle encounters strong headwinds, power demand should increase and the system would call for higher engine RPMs in hybrid mode.

So what I'm saying is that I think the relationship of engine RPM to final drive ratio in our eCVT hybrids cannot be thought of using the models we are accustomed to with automatic or manual gearboxes where each gear has a fixed ratio of engine RPM to vehicle speed, because the eCVT uses a planetary gearset which can widely vary it's input to output RPM ratios.

Are these correct assumptions on my part or am I off in the weeds with this line of thought?

I notice traveling down a hill by my house the engine in my 23 seems to really rev. Happens evertytime. When I get to the bottom it stops reving like it just shifted to a higher gear. It is definetly noticable. Last time I put the selector into neutral. Don't know if you ever experienced that? Thanks Rick

 

[MakinDoForNow]

I notice traveling down a hill by my house the engine in my 23 seems to really rev. Happens evertytime. When I get to the bottom it stops reving like it just shifted to a higher gear. It is definetly noticable. Last time I put the selector into neutral. Don't know if you ever experienced that? Thanks Rick

That high rpm going downhill is engine braking used when the HVB is charged to 72%+/-. I think max rpm ice braking is around 4800.

 

[Shelbyv8]

Most of the engine sound is artificially generated, so you can't go by that either.

 

[Robot-Wrangler]

I am (easily) confused.

The hybrid eCVT does not directly connect the engine to the final drive like an automatic which has locked it's torque converter or a manual gearbox. It is instead connected through a planetary gearset and so does not have a fixed drive ratio (of course, with AWD the PTU and rear diff have fixed ratios).

So I would think that the engine RPM is not directly linked to the speed of the vehicle - if for example you are doing 65MPH on level ground and the vehicle is operating in hybrid mode, then transition to a downhill slope, the amount of power demand should decrease, allowing the engine to slow its RPMs or even to shut off as the system goes into regenerative mode. Likewise if you are doing 65MPH on level ground and the vehicle encounters strong headwinds, power demand should increase and the system would call for higher engine RPMs in hybrid mode.

So what I'm saying is that I think the relationship of engine RPM to final drive ratio in our eCVT hybrids cannot be thought of using the models we are accustomed to with automatic or manual gearboxes where each gear has a fixed ratio of engine RPM to vehicle speed, because the eCVT uses a planetary gearset which can widely vary it's input to output RPM ratios.

Are these correct assumptions on my part or am I off in the weeds with this line of thought?

Well said. I have a '25 Hybrid AWD and do all kinds of driving. I have a car scanner Bluetooth OBDII reader and display info on my dash.

If you are towing heavy uphill at 70, you may see close to 5,100rpm. If you are unloaded and on level ground at 70mph usually 2,200rpm.

Compare this to downhill and regen kicks in with no engine or if you are in L driving range the rpm can go way up to more than 4,000rpm as a form of engine compression braking. It's weird to say the least.

When my scanner comes home next week, I'll get you a fresh photo or two if you'd like.

 

[Robot-Wrangler]

When my scanner comes home next week, I'll get you a fresh photo or two if you'd like.

 

[broman52]

I am (easily) confused.

The hybrid eCVT does not directly connect the engine to the final drive like an automatic which has locked it's torque converter or a manual gearbox. It is instead connected through a planetary gearset and so does not have a fixed drive ratio (of course, with AWD the PTU and rear diff have fixed ratios).

So I would think that the engine RPM is not directly linked to the speed of the vehicle - if for example you are doing 65MPH on level ground and the vehicle is operating in hybrid mode, then transition to a downhill slope, the amount of power demand should decrease, allowing the engine to slow its RPMs or even to shut off as the system goes into regenerative mode. Likewise if you are doing 65MPH on level ground and the vehicle encounters strong headwinds, power demand should increase and the system would call for higher engine RPMs in hybrid mode.

So what I'm saying is that I think the relationship of engine RPM to final drive ratio in our eCVT hybrids cannot be thought of using the models we are accustomed to with automatic or manual gearboxes where each gear has a fixed ratio of engine RPM to vehicle speed, because the eCVT uses a planetary gearset which can widely vary it's input to output RPM ratios.

Are these correct assumptions on my part or am I off in the weeds with this line of thought?

Any internal combustion engine, whether one that is a stand-alone powerplant or one that is "assisted" by an e-drive, will use MORE FUEL based on what RPM the engine is running at. The higher the RPM, the more fuel it takes to sustain that RPM. It's simple physics. Higher RPM's requires more air, more air requires more fuel. It doesn't matter what speed the vehicle is moving at, what matters is what RPM the engine is running at. In my 2026 AWD Lariat hybrid, the engine is pretty much running the entire time I'm at any highway speed... You will get better gas mileage at 60 mph than you will at 80 mph, it doesn't matter one bit if the e-drive is assisting or not. These hybrids don't have enough stored battery power to really assist that much because they require almost constant charging - so if the engine is not being assisted it's because the battery at that point is being re-charged by the engine. It's a constant balancing act between available battery juice and available engine power and re-gen power, like coasting down a hill... and then, nobody who coasts down hills does it without having to power up hills as well...

 

[Big-Foot]

What

what App is that?
—
my 26 Lariat AWD Hybrid showed ~2300 RPM at 75 mph. It varies depending on load (uphill/downhill).
Scangauge II in my truck.

 

[MaverickDragon]

My post above was about how the gearing in the hybrid has no fixed input-to-output ratios. Have a look:

Thanks for the video post...
Is it just me, or could the guy doing the rebuild benefit from a transmission stand.
That box was doing a lot of rotations....

Especially for the last few minutes of the video, I would not think a transmission was being worked on... That is truly a different beast!

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