Sounds like Stellantis is on the right path.

[rruff]

This thing would ideally have a small engine optimized to run at a steady speed and max output... maybe a gas turbine? The engine does not need to supply as much power as the average demand, but close... like 80% or so.

The driver can select how they want the charging to operate, depending on how they plan to use it. If no long trips are planned the engine stays off and you charge at home. If you set off on a long tow, you start charging immediately and the engine runs at full power the whole time. If it can't keep up, then you'll have to charge as well when you get gas. Optimally you'd want both to be drained at the same time. Or maybe not if you don't want the hassle of electric charging.

Anybody know what the typical average demand would be while towing a big 14,000 lb trailer at 75 mph? 150 hp is probably not far from reality.

 

[85_Ranger4x4]

This thing would ideally have a small engine optimized to run at a steady speed and max output... maybe a gas turbine? The engine does not need to supply as much power as the average demand, but close... like 80% or so.

The driver can select how they want the charging to operate, depending on how they plan to use it. If no long trips are planned the engine stays off and you charge at home. If you set off on a long tow, you start charging immediately and the engine runs at full power the whole time. If it can't keep up, then you'll have to charge as well when you get gas. Optimally you'd want both to be drained at the same time. Or maybe not if you don't want the hassle of electric charging.

Anybody know what the typical average demand would be while towing a big 14,000 lb trailer at 75 mph? 150 hp is probably not far from reality.

I grossed 13k a couple years ago hauling soybeans to town with a 50hp tractor. We were a long ways from 75mph (like 68mph less). Power wasn't really an issue but it was almost kinda sporty on gravel road hills with no tongue weight.

 

[rruff]

Did some investigating of towing tests, and I think 1.5 kWh/mi at 75 should about cover it... unless your trailer is a tall brick.

That's 1.9 kWh/minute, or 112 kW, which is 150 hp. It makes sense that they'd use something off the self that is capable of that instead of a new engine, but if this concept becomes popular I think lighter and more efficient engines will be developed.

 

[driveby]

Agreed, whatever is in the parts bin is best. Especially if it’s already NA/CARB etc approved. And whatever will run in the most optimal power band for the least fuel is the right choice.

 

[85_Ranger4x4]

Did some investigating of towing tests, and I think 1.5 kWh/mi at 75 should about cover it... unless your trailer is a tall brick.

That's 1.9 kWh/minute, or 112 kW, which is 150 hp. It makes sense that they'd use something off the self that is capable of that instead of a new engine, but if this concept becomes popular I think lighter and more efficient engines will be developed.

They have smaller, most if not all are boosted which is probably less than ideal for this kind of drive cycle where the engine may go long periods without running and not really get any better economy because it is in the boost to make spec hp. And then you have intercooler etc to fuss over.

 

[skrypj]

This is a pretty good interview with the propulsion engineer for the RamCharger

 

[nickw]

Agreed, whatever is in the parts bin is best. Especially if it’s already NA/CARB etc approved. And whatever will run in the most optimal power band for the least fuel is the right choice.

It's an engineering trade-off power:weight ratio vs power:fuel ratio...in some cases a heavy, low revving diesel may be the best powerband and least fuel but it could weight 10x what you can afford....or a small high RPM gas engine that gets 10% worse economy but weighs 1/10th is the right call, it's ends up being rocket science to a certain extent....power, engine weight and fuel weight and how they scale given all the other constraints.