Some musings on future power trains

Groover wrote:
OP here, I feel the need to make a few comments.
I used the 3.5 PowerBoost engine for an example simply because it is the only hybrid engine I am aware of that is available right now and I never said to use it in its current form or output levels. I just used for illustration of what could be.

That said, as far as I can tell everyone throwing shade at it has no first hand experience with it. I own two. The first is a 2013 model I gave to my daughter for driving to college and towing her horse trailer around. I picked the truck because it had been on the lot long enough to get some serious discounts. I don't even know what type of trailer tow package it has but she used it to pull her 3 horse trailer for several years then moved up to a gooseneck with living quarters. The only trouble we have had from the truck is with the brakes and it is over 130,000 miles now. The second EcoBoost is a 2016 model that is equipped with max towing package and has been pressed into service towing an equipment trailer giving me a GCWR around 18,000lbs. No trouble after nearly 5 years and 21,000 miles of pulling the trailer in addition to grocery getting. My experience trumps the opinions of speculators in my book.

I want a package that can be used with current technology boondocking or even in Glacier NP that has no power run to the campsites and very limited generator hours. The package I suggested would do that. The Ecoboost is so quiet that you could probably get away with running it all the time, especially if the exhaust was run up to the roof.

Heavy vehicles have the potential to get more benefit from a hybrid drive system than light ones since the benefit is derived from saving energy that would otherwise be put into the brakes and that is a function of the pull of gravity plus momentum(both mass related) minus the air drag. The mpg may not increase as many miles per gallon but the number of gallons saved would be much more in a motorhome than in a Prius.

A good hybrid system could take a lot of the peak loads off of whatever motor is used.

The PowerBoost 3.5 is rated for 530lb-ft of torque, 90% as much as my Cummins. That is a peak output but it could probably be increased with a little effort and a few thousand dollars.

I am looking for a package that doesn't run the price through the ceiling. I think that I what suggested might even enable a price reduction.

First, the 3.5 EcoBoost has turned out to be a good engine but they aren't putting it in the 3/4 and 1 ton trucks for a reason. We have no experience with the 3.5 PowerBoost as it's just coming out for 2021, so no one other than the Ford Engineers has any idea how it will hold up. The 3.5 EcoBoost has a decent reputation but 130,000 miles towing a 5-6k horse trailer isn't a long term durability test. Probably more important, what percentage of miles were towing? 21,000 miles is pretty much still brand new, so doesn't tell us much either. But again, it's a different drivetrain from the PowerBoost.

Now to the actual issue you brought up.
- If you just want to run house loads without running the generator, you can install a 5-10kwh lithium battery bank and do that now without getting an exotic drivetrain. By itself, it's certainly not justification to develop a hybrid drivetrain.
- Running a big motor as a generator all the time defeats the purpose. Also, most modern vehicle engines are pretty quiet. I have a 2008 V10 and it's hard to hear when idling from 20ft away...they still aren't going to be happy if they catch you running it, if for no other reason than to hold the moral high ground when they cite people running noisy generators.
- If you are driving to work in stop & go traffic with your MH, true, there is a potential to save a lot more fuel relative to a Prius. Problem is most miles in RVs are in rural areas under light traffic conditions. Most people avoid driving in rush hour when they do pass thru a city. At steady speeds, hybrids really don't provide a benefit over an appropriately sized ICE and unlike pickups that can have CGVW that range by a factor of 3...your average MH CGVW changes very little typically, so the engine can be better dialed in to the rig.
- It wouldn't really take much load off the motor in most conditions. Once up to speed on the freeway, the load is roughly the same and the batteries aren't designed to provide constant power for hours, so it's the ICE doing all the work.
- Diesels are more heavily built to handle the much higher compression ratios compared to gas engines. A side benefit is you can run them at a higher percentage of peak output without wearing them out quickly. So it's not the peak HP/Torque but the allowable continuous rating that matters, I think you will find the 3.5 continuous rating is drastically less than the cummins.

The PowerBoost only has a 1.5kwh battery bank feeding a 35kw electric boost motor. That means it can provide max boost for 2.5 minutes, so climbing a long grade, it's not going to do much of anything. It's really only useful for accelerating in stop and go traffic. For towing and climbing steep grades, the base 3.5l turbo charged gas engine is going to be doing pretty much all the work.

Why did Ford go this route? Because most people don't tow with 1/2 ton trucks for most miles. They run around empty and use it as a commuter vehicle where the hybrid aspect can provide significant benefits all while giving a very peppy performance boost running empty. It will probably do OK towing but when towing, the efficiency will go out the window (as shown by people complaining about mpg towing with the EcoBoost).

A standard Hybrid really won't provide a benefit to your average MH usage profile. A Plug-In-Hybrid could provide some but it wouldn't nearly as good as for a commuter vehicle and at what cost?

If you look at the commercial world, you see divergent approaches that are dialed in to the usage patterns:
- City buses have had great success with hybrid systems. A city bus typically peaks at around 45mph but usually is ranging between 0-35mph with stops every 1/4-1/2 mile. A city bus is pretty much constantly accelerating or decelerating. This is perfect for a hybrid.
- Long distance trucks, they are almost all looking at pure battery power because there is pretty much nothing to gain running at steady speeds using a hybrid.
- Short range delivery vans (like UPS trucks), they are looking at battery only but this is driven by the relatively short range they need. 200mile range can service most delivery routes and then it's easy to park at a designated lot that can be outfitted with slow charge ports as the trucks typically sit 10hr or more overnight. Where city bus service has limited hours, pure battery can work as the range may be acceptable and as with delivery trucks, there is a storage yard that can be outfitted with charging ports to charge over night.

Probably the closest comparison for a MH would be long distance trucks...and they aren't going hybrid.