Power reduction on extended high speed driving?

[DreamWeaver21]

I've had my 2022 hybrid maverick for ~1.5 years now and I have experienced the "typical" issues (wonky slow speed brakes, radio freezing, etc.) but I had a new to me issue happen last weekend.

I am in Germany and was coming back from Czech last weekend. I was on the autobahn without a lot of traffic so I had the cruise set at 145km/hr (90mph) for 30-40 minutes. Road conditions were good and there were just rolling hills. Going up a slight but steady incline, my speed dropped a couple of km even though the cruise was set higher. I also noticed the "power meter" was only at 50%. When I crested the hill, it got back to normal. On the next hill, the truck slowed again. I turned off the cruise and ended up pressing the go pedal more and more trying to keep speed until it was floored. The "power meter" never went above 60% or maybe 70% and I am sure I have seen it at 100% before. The truck also stumbled a little bit like it was hitting a speed limiter but I was not close to that speed (I have hit that before though).

Temp gauge was normal and there were no lights or warning messages on the screen, it just didn't seem to want to go any more.

Obviously it is a modestly powered aerodynamic brick going at a pretty good clip so the gas motor was humming pretty good but it seems like it shouldn't be tapped out.

Is there a known built in limitation that I am not tracking? I haven't been in a place to check that the truck can still make 100% power on the gauge since then but it was driving normal in city traffic since I had this issue.

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[GPSMan]

I've had my 2022 hybrid maverick for ~1.5 years now and I have experienced the "typical" issues (wonky slow speed brakes, radio freezing, etc.) but I had a new to me issue happen last weekend.

I am in Germany and was coming back from Czech last weekend. I was on the autobahn without a lot of traffic so I had the cruise set at 145km/hr (90mph) for 30-40 minutes. Road conditions were good and there were just rolling hills. Going up a slight but steady incline, my speed dropped a couple of km even though the cruise was set higher. I also noticed the "power meter" was only at 50%. When I crested the hill, it got back to normal. On the next hill, the truck slowed again. I turned off the cruise and ended up pressing the go pedal more and more trying to keep speed until it was floored. The "power meter" never went above 60% or maybe 70% and I am sure I have seen it at 100% before. The truck also stumbled a little bit like it was hitting a speed limiter but I was not close to that speed (I have hit that before though).

Temp gauge was normal and there were no lights or warning messages on the screen, it just didn't seem to want to go any more.

Obviously it is a modestly powered aerodynamic brick going at a pretty good clip so the gas motor was humming pretty good but it seems like it shouldn't be tapped out.

Is there a known built in limitation that I am not tracking? I haven't been in a place to check that the truck can still make 100% power on the gauge since then but it was driving normal in city traffic since I had this issue.

I am 99% sure of what happened.

At those speeds the generator is spinning about 15,000 rpm and the generator gets hot. Also the generator has a rev limit. About 15,000 rpm.

I'm pretty sure you overheated the generator, which is not tied to the gauge on the dash, you need a scanner plugged into the data port to read generator temperature.

You CAN NOT sustain over 50% power output in a Maverick for more than 10-15 minutes. The generator heats up.

Instead of going 90 mph uphill I went 60 MPH uphill towing a large trailer and saw the generator get hot with my scanner.

50% and under all day long is fine.

 

[DreamWeaver21]

Could be. I have Forescan and a cable but wasn't connected. Do you know if that is stored in the history?

 

[GPSMan]

Could be. I have Forescan and a cable but wasn't connected. Do you know if that is stored in the history?

If not hot enough to cause damage and throw a code, probably nothing stored. The fact you had no warnings probably means no codes.

This is a GUESS:

You get a power output reduction at 265°F to see if that cures the "heating" but you don't get a code or warning until 285°F.

If my guess is not perfect, it is probably pretty close to this.

 

[GPSMan]

Now. When I was towing over those camel humps in the road, generator temperature would climb 50°F in a couple of minutes, but cool equally fast on the downside of those camel humps.

The hybrid battery is NOT working hard at highway speeds. The generator is. ICE spins generator and generator sends power to traction motor. Like a train locomotive. The battery does VERY little.

Radiator water was much more constant and only varied a handful of degrees.

HTH, but I think it describes your scenario.

 

[AutobahnSHO]

Better than the 110mph limiter on older (late 90s, early 00s) Chrysler minivans! It would just shut power off until you coasted down to 90mph. Very dangerous!

BTW do you get people ogling your truck there? Super unique!

I bought a 91 Taurus SHO when I lived in Mannheim.

 

[bgn]

The Maverick is basically a monster truck over there.

 

[clavicus]

Now. When I was towing over those camel humps in the road, generator temperature would climb 50°F in a couple of minutes, but cool equally fast on the downside of those camel humps.

The hybrid battery is NOT working hard at highway speeds. The generator is. ICE spins generator and generator sends power to traction motor. Like a train locomotive. The battery does VERY little.

Radiator water was much more constant and only varied a handful of degrees.

HTH, but I think it describes your scenario.

Can you clarify:
Depending on the rotation of the wheels (ring gear) compared to the sun gear (generator motor), thats how the power is applied from the planet carrier/planets (engine) to the wheels (ring gear) directly — no need whatsoever to use generator motor to make any electricity whatsoever because that’s dumb since it’s a lossy process? The traction motor aint doing NoThInG at speeds above like 75+ right?

Anyway, is the issue that causes power limiting that the generator motor needs to be forced to resist the spin from the engine — spin slower to force power to be directed only to the wheels — and that resistance generates heat somewhere? Or is it the opposite and that the generator motor is spinning too fast for too long, but it needs to keep spinning faster to provide closer to 100% power at that speed?

I dunno if this question makes sense.

 

[GPSMan]

Your question makes sense.
What you are thinking is one possible operating mode.

ScanGauge shows independent torque from the traction motor, generator motor, and engine.

Traction motor torque can be positive or negative. Generator torque can be positive or negative. Engine torque is always positive.

I've observed positive torque going to the wheels from the traction motor. At the same time battery state of charge remains constant.

Therefore power to drive the traction motor is coming from other than the battery. Ergo, generator.

This is also how it works moving in reverse and the battery is low.

Probably because it is a torque multiplier. Probably not as lossy as you imagine. A horsepower is a horsepower right? But someone figured out, an electric horsepower has more torque than an ICE horsepower.

"Diesel" Train locomotives are electrically driven. The diesel engine is in no way connected to the wheels.

I have a diesel D6 Bulldozer at work.
The diesel engine is in no way connected to the drive. It too is 100% electrically driven. You could also have a hydraulic motor turning the drive. The newest bulldozers are electrically driven.

 

[GPSMan]

Can you clarify:

...is the issue that causes power limiting that the generator motor needs to be forced to resist the spin from the engine — spin slower to force power to be directed only to the wheels — and that resistance generates heat somewhere? Or is it the opposite and that the generator motor is spinning too fast for too long, but it needs to keep spinning faster to provide closer to 100% power at that speed?

I thought of this a bit more and I think I have a better answer.

It's the second. For sure the second.
The generator gets hot because it is generating high wattage for an extended period. Not the other way around. NOT because it is consuming wattage for too long.

 

[RCollins]

They have a liquid cooled hybrid battery, so why not a liquid cooled generator.

 

[MakinDoForNow]

I thought of this a bit more and I think I have a better answer.

It's the second. For sure the second.
The generator gets hot because it is generating high wattage for an extended period. Not the other way around. NOT because it is consuming wattage for too long.

My take is that at 90+ mph the ice will be delivering 100% of available torque to wheels thanks to the planetary gear set LESS the required electrical power needed to be generated. The generator will be forced to run harder to cool itself through the radiator coolant assisted by the AC condenser. Would be best to turn off all possible electric items radio, lights, dash cam, turn of AC or set cooling to 80 or heat to 61. Do not set to max either high or low. If trans fluid is not 100% at full level then keeping at lowest possible temp will take more electricity also. FYI is saw John Kelly at Weber State video in which mechanics from the Bahamas were there and they stated they changed the hybrid transaxle fluid in focus hybrid annually because of heat issues in their climate. Ours is much improved from that one but the operating conditions he is experiencing at 90mph probably would be a vote to check his trans fluid level tested at 35-50k miles and have a sample tested. Most likely electrical current generated and used in transaxle would be minimized due to heat generation.

 

[GPSMan]

They have a liquid cooled hybrid battery, so why not a liquid cooled generator.

It is to a degree (no pun intended).
But everything has limits.

 

[GPSMan]

@MakinDoForNow I read your above three times. Maybe it's the late hour. But I don't understand what you are saying. I disagree with most and don't understand the rest.

1. The electrical demands of accessories like dash cam, radio, lights, are minuscule compared the power demands of driving (moving) a ~2 ton vehicle.

2. The electrical demand of air conditioning is moderate, 2 or 3 horsepower equivalent.

3. Heating comes from gasoline, not electricity. The heater core is an extra radiator for the truck. The hotter you turn up the cabin heat, the cooler your truck runs.

 

[ltelmo]

I just drove a 1000 miles mostly on the interstate at 70 plus in west Virginia on grades of 7 to 8% for continuous periods of up to 7hrs on our return with no issues on power and or temps. I noticed no power reductions at all

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