What happens when tuners realize the hybrid HP/TQ numbers?

[The Real Maverick]

@heady

You've said a lot and done a lot of thinking. But you are missing something.

I have the FWD HF45 but I think you'll agree it is remarkably similar.

But my MG1 is standing still, not spinning, at low throttle and low engine rpm.

You wrote:
". In the planetary, the torque ratio and RPM target for the engine speed restricts generator/starter/(MG1) power output. At wide open throttle, the power output of this motor falls to zero at ~58MPH and begins to rise again after the motor direction change."

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[heady]

@heady

You've said a lot and done a lot of thinking. But you are missing something.

I have the FWD HF45 but I think you'll agree it is remarkably similar.

About 58 MPH is a tipping (direction change) point for MG1 in mine also.

But my MG1 is standing still, not spinning, at low throttle and low engine rpm.

You wrote:
". In the planetary, the torque ratio and RPM target for the engine speed restricts generator/starter/(MG1) power output. At wide open throttle, the power output of this motor falls to zero at ~58MPH and begins to rise again after the motor direction change."

It changes based on engine RPM, the post quoted is for the 5600 RPM/151.93ft-lb state, there's another state I provided for 4000 RPM/155ft-lb that shows how the gen speed varies. Gen speed and torque are completely dependent on engine speed and torque.

*Look at HeyBales datalog, the gen speed varies pretty wildly at part throttle, and the crossover point moves up to about 63.4 mph in his exact conditions. There is no fixed point or crossover except in a steady state engine condition of both RPM and torque. In fact, the generator speed in his log varies from -190 RPM to +1335 RPM at the exact same road speed as the transmission changes gear ratios in the planetary.

 

[The Real Maverick]

And as engine RPM changes, MG1 can be at zero (or close) at different wheel speeds.

 

[The Real Maverick]

It changes based on engine RPM, the post quoted is for the 5600 RPM/151.93ft-lb state, there's another state I provided for 4000 RPM/155ft-lb that shows how the gen speed varies. Gen speed and torque are completely dependent on engine speed and torque.

*Look at HeyBales datalog, the gen speed varies pretty wildly at part throttle, and the crossover point moves up to about 63.4 mph in his exact conditions. There is no fixed point or crossover except in a steady state engine condition of both RPM and torque. In fact, the generator speed in his log varies from -190 RPM to +1335 RPM at the exact same road speed as the transmission changes gear ratios in the planetary.

I still think you are missing something.

I'm not saying mine was a little off yours.

I'm saying in mine I think it is IMPOSSIBLE for my MG1 to be stationary at 5600 RPM engine and 58 MPH.

Which would imply HF45 and HF55 are vastly different. And I don't think that is the case.

 

[heady]

And as engine RPM changes, MG1 can be at zero (or close) at any wheel speed.

Yes. That's how the transmission changes gear ratios. Gen speed is set by desired engine speed, that's what makes it a CVT. Of course if Gen speed was always around zero, it wouldn't act as a CVT, it would just be a fixed ratio. Gen speed is often around zero in normal driving because that's the normal transmission ratio you'd want at light loads. HeyBales has the HF45 like yours and at the end of his acceleration run the Gen speed is over 11,000 RPM at 60 mph at 45% throttle and requesting 140 ft-lb. from the engine at 5200RPM. During the coast down portion, it's at about 50 RPM at the same speed, 60 mph while requesting 52ft-lb. from the engine at ~1360 RPM.

 

[The Real Maverick]

You said:

"Generator speed is often around zero in normal driving..."

I say it is rarely zero.

How do we resolve this?

 

[Escapologist]

Obviously we gotta make you drive different

 

[heady]

You said:

"Generator speed is often around zero in normal driving..."

I say it is rarely zero.

How do we resolve this?

It will never very likely be precisely zero, except for the exact split second moment of a rotation direction change, it will often be around zero as mentioned in low RPM, low throttle cruise, an inverter can't really hold a rotor perfectly stationary in a dynamic load environment when other parts of the planetary are moving and loads and planetary accelerations are always changing by at least minute amounts. We can't really keep an engine at exactly 5600.0000 RPM or the road speed at exactly 58.4117 MPH in real world conditions, for instance.

 

[The Real Maverick]

I'm not splitting hairs.

I've had a scanner on my dash since 2005 Hybrid Escape.

All the Weber Auto tear-downs show all generations of eCVT are remarkably similar. Only mild motor changes and a few tooth changes here and there.

Generator zero at 5600 ICE I've never seen.

However; I have a big hill climb leaving work and I can go WOT for half a mile and will real world test for this.

 

[heady]

Have you seen the generator switch directions? Then you've "seen" it cross through zero; it doesn't matter if your data logs have enough resolution to capture every RPM incremental change by ones (10,9,8,7,6,5,4,3,2,1,0,-1,-2,-3.... etc). I'm not even sure what your question is or what the purpose of this digression is, are you saying you've never seen the generator switch directions as demonstrated in HeyBales log, or that crossing through a zero RPM point is not on the number line between all positive and all negative RPM values? (edit: I think I get what you were saying now, that the low generator RPM at 5600 RPM was impossible, not the low generator RPM during driving around in general cruising was impossible)

The CANbus PIDs simply aren't that fast, you can see in HeyBales log that the generator can go from over +11,000 rpm to -190 RPM in less than four seconds, in order to display that range incrementally in a log would take a ridiculously crazy bus speed and sample rate....

Data logging a WOT run will be helpful though, it will let me compare the estimated speed values with a set of collected values. My equation I tried to set up for the counter-rotating case, but there is also a co-rotating case that is different, too. Also, the equation could easily be translated wrong into Excel as well, but that's easy enough to fix if we spot an error. (I think the way I tried to set up the counter-rotating from the start/low RPM is what caused the error)

Here's the spreadsheet with the (hopefully correct) co-rotating sun gear values, you can see why I didn't use it by default for the WOT run simulation/estimation when I first looked at it, at low speeds it violated the Gen motor HP spec and the motor RPM is really crazy high over 19,000 RPM; so I expect it might limit power output and RPM from the engine below 23 MPH, take a look and see what you think (numbers for the HF45 will be slightly different due to gearing changes):

 

[The Real Maverick]

Have you seen the generator switch directions? Then you've "seen" it cross through zero; it doesn't matter if your data logs have enough resolution to capture every RPM incremental change by ones (10,9,8,7,6,5,4,3,2,1,0,-1,-2,-3.... etc). I'm not even sure what your question is or what the purpose of this digression is, are you saying you've never seen the generator switch directions as demonstrated in HeyBales log, or that crossing through a zero RPM point is not on the number line between all positive and all negative RPM values? (edit: I think I get what you were saying now, that the low generator RPM at 5600 RPM was impossible, not the low generator RPM during driving around in general cruising was impossible)

The CANbus PIDs simply aren't that fast, you can see in HeyBales log that the generator can go from over +11,000 rpm to -190 RPM in less than four seconds, in order to display that range incrementally in a log would take a ridiculously crazy bus speed and sample rate....

Data logging a WOT run will be helpful though, it will let me compare the estimated speed values with a set of collected values. My equation I tried to set up for the counter-rotating case, but there is also a co-rotating case that is different, too. Also, the equation could easily be translated wrong into Excel as well, but that's easy enough to fix if we spot an error. (I think the way I tried to set up the counter-rotating from the start/low RPM is what caused the error)

Here's the spreadsheet with the (hopefully correct) co-rotating sun gear values, you can see why I didn't use it by default for the WOT run simulation/estimation when I first looked at it, at low speeds it violated the Gen motor HP spec and the motor RPM is really crazy high over 19,000 RPM; so I expect it might limit power output and RPM from the engine below 23 MPH, take a look and see what you think

I see generator change direction all the time. But always at moderate speeds and moderate loads.

Below is a highly smoothed graph.

Pedal to the floor 10 MPH to 70 MPH.
Wide open throttle.

The generator goes to red line right away and holds at red line (12,750 - 12,850 and I never saw 13k this whole test.)

The generator hits it's redline way before the ICE does.

Then, once the ICE gets to 5600, it holds 5600 then the generator slowly tapers down as road speed goes up.

At 70 MPH the generator is a long way from zero as you can see.

I am saying your "formula" is not correct. It is impossible for the generator to slow and then reverse direction at WOT, 5600 RPM.

Edit: I see you revised your formula some. Getting closer.

 

[heady]

Yeah the formula is the same, but I had an error on the input for the sun gear teeth, I introduced a negative value there when I saw such high generator RPM at low speed thinking that was wrong. It looks like from your log/graph that high rpm generator at low speeds is really what happens! We just can't hit redline below ~30 mph, the generator speed limit seems to prevent it. It looks like with the lower gearing of the 2025 that full engine RPM might not be available until ~45mph if the generator RPM limit is the same as yours and the tooth counts I have are correct, I'll have to make a datalog and check.

It only takes five or ten minutes to make a spreadsheet like this so if anyone wants one with hf45 gearing let me know we should be able to get that from maktrans, the only variables on the sheet are the engine RPM and torque, and tire size. Everything else is a constant or calculated value. Very little work involved with these calculations, it takes much longer to explain (and debug) than to do them.

 

[The Real Maverick]

Yeah the formula is the same, but I had an error on the input for the sun gear teeth, I introduced a negative value there when I saw such high generator RPM at low speed thinking that was wrong. It looks like from your log/graph that high rpm generator at low speeds is really what happens! We just can't hit redline below ~30 mph, the generator speed limit seems to prevent it. It looks like with the lower gearing of the 2025 that full engine RPM might not be available until ~45mph if the generator RPM limit is the same as yours and the tooth counts I have are correct, I'll have to make a datalog and check.

It only takes five or ten minutes to make a spreadsheet like this so if anyone wants one with hf45 gearing let me know we should be able to get that from maktrans, the only variables on the sheet are the engine RPM and torque, and tire size. Everything else is a constant or calculated value. Very little work involved with these calculations, it takes much longer to explain (and debug) than to do them.

Have a look here also:

https://www.mavericktruckclub.com/f...r-ratios-hf45-transaxle-technical-info.66656/

 

[heady]

I was able to do a datalog on the 2025 this afternoon, a zero to 85 mph run at full throttle logged with Forscan Lite. As you experienced, the full engine RPM is not available at low speeds. I was able to compare the predicted vs. actual generator speeds between the two at different road speeds once the engine got up to full RPM at 40.4 MPH

Prediction Road Speed	Predicted Gen. Speed	Actual Road Speed	Actual Gen. Speed
40	13899.64	40.4	13697
45	13166.51	44.7	13058
50	12433.38	50.3	12238
55	11700.25	55.3	11450
60	10967.11	60.3	10746
65	10233.98	65.2	9981
70	9500.85	70.2	9231
75	8767.71	75.2	8523
80	8034.58	80.2	7752
85	7301.45	85.1	7007

The small difference in RPM predicted vs. measured can be adjusted out by setting the tire diameter in the spreadsheet to account for difference between it and the VSS calibration in the truck, and setting the values in the Road Speed (MPH) column to match the values from the datalog. I'm pretty sure the formula and gear ratios are correct now for the 2025.

Predicted generator torque was 43.05 ft-lb against 151.93 ft-lb engine torque; measured values were an average of 39.51 ft-lb against 138.2 ft-lb. The spreadsheet predicts 39.16 ft-lb generator torque against 138.2 ft-lb.

The max generator speed was hit in the log at 14,367 RPM at 33.6 MPH.

Traction motor torque briefly requested over 235 ft-lb from 3 to 10.6 MPH in the 2025, which is consistent with the claim in this article.

 

[AutobahnSHO]

I've never seen tuners do anything with electric or hybrid drivetrains, probably because they don't know or care anything about them.

OR because it's not worth their time- Toyota has been building the Prius for a long time and the Maverick is (very largely) based on that experience (Ford paid Toyota for hybrid technology for awhile).

My bet is the hybrid powertrain is at pretty close to most efficient configuration already. There's not much to "tune".

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