It may make sense to have the generator output high voltage AC 3 phase directly into the drive system, since the E motors runs on 3 phase AC. The range extender would use the motor's inverter to convert the AC into DC to charge the battery.
AC generators are more efficent, and sending power directly to the wheels bypassing the battery reduces wear on the battery, high wattage charging.
This also allows the battery and RE to work in parallel, reducing peak energy output from the battery pack.
This setup would make the range extender plug and play with pure BEV trucks.
I don't think it needs that much power. Honestly, a small V6 or large I4 should be enough. 200-220hp should be enough.
The perfect engine would be a small gas turbine.
I think people are overestimating the usefulness of large motors in this scenario. The majority of the time this thing shouldnt be running. Which creates its own unique challenges.
The number of energy conversions in EREVs is significant once the generator kicks in and each energy conversion step results in an efficiency loss. Here is what I see happening once that generator starts running:
Gasoline (chemical) energy converted to mechanical energy.
The gasoline is burned in the EREV's ICE to create mechanical (rotational) energy. Probably the biggest energy loss occurs here. Note that all ICE vehicles encounter this loss.
Mechanical energy converted to DC electrical energy
The crankshaft of the ICE is driving a generator to produce DC electrical energy.
DC electrical energy converted to chemical energy
The DC output of the generator is sent to the EREV's battery and converted to chemical energy.
Chemical energy converted to DC electrical energy
The EREV's battery converts the stored chemical energy back to DC electrical energy.
DC electrical energy converted to mechanical energy
The DC electrical energy released by the battery is converted to mechanical (rotational) energy via one or more electrical motors.
Note: The EREV may be designed to skip steps 3 and 4 if the generator's DC output bypasses the battery and is directed straight to the electric motors. I assume this is how a Diesel/Electric locomotive works. But, some portion of the output probably still must go to the Li-ION battery and a 12-volt battery.
Exactly the kind of modular I was thinking as example. I had a car once with half a V8, and some manufacturers have essentially taken two inline-six designs to make a V-12. Anyway, my Ford V-10 was rated up to 22,000 pounds GCWR in E-450 applications. My thought was that a 5-cylinder truck gas engine around 3.4 to 3.7 Liters would have been more economical all around; and still have plenty of power for the job.
Agree. When manufacturers were recently moving towards EVs as fast as possible, I can see how new engine development would have been halted. Maybe they will reconsider somewhat, particularly with hybrid-optimized engines. I read both GM and Ford were working on new inline-6 turbo engines that were canceled. Not implying these were necessarily for hybrids.
As far as Stellantis goes, I can’t relate at all wanting to buy any large vehicle with a 3L twin-turbo six making 500 HP. You’d have to almost give it to me. I know and accept that auto enthusiasts want or feel they need 500 HP, but I wonder how many actual buyers in the general public view vehicles that way. I’m more of the very opposite mindset wanting my cars follow the KISS principle. I prefer (liked) inline engines, naturally aspirated, and installed longitudinally. I say “liked” because I’m not sure that combination even exists today. I can’t recall any off the top of my head, at least no vehicle I’d be interested in buying.
Only thing I would add is that if Stellantis continues to have problems replacing Hemi V8 with Hurricane, it’s not because it’s a straight six. Hurricane happens to be a straight six, but that’s not the primary cause of their problems AFAIK.
Came here to say this as well, I see it's been discussed and I'm not really convinced, but I never did finish my engineering degree so...
Seems to me adding the cost and complexity and relatively low tq numbers of a DOHC v8 doesn't really make sense in a generator application. Smaller displacement godzilla or even one of the smaller ecoboost v6s with big tq numbers make more sense in my head, though that would add even more complexity and fuel consumption under heavy load with a turbo is tricky.
Honestly don't like these EREV things, seems like a lot of different crap to go wrong. It's a good stop gap measure, but I personally think they'll end up obsolete sooner than later as battery tech evolves. A superduty one does fit my personal use case right now though. 99% <100 miles a day towing ~10k with a couple big road trips towing several hundred miles per year.
At the time, the brief was to develop a new cyclone V6 engine that could be used in RWD and FWD applications.
The Cyclone V6 was justified because it allowed Mulally to kill off loads of other V6 designs from previous decades.
As we’ve discussed before, the cost of replacing the existing V6 with an I-5/I-6 design is either not justified or not
a priority for Ford otherwise it would be copying Stellantis right? So maybe it’s better to watch them brag about
their I-6 engine while they slowly go bankrupt.