Harvester owners (future) here! Who's going EREV Electric + Gas Range Extender 🔋⛽️

[Efthreeoh]

I'm hoping Scout does this right and uses a clean sheet design for the engine and generator. I hope the plans are not to repurpose a corporate VW car engine. Powering just a generator can allow for a more efficient combustion cycle and lighter weight engine to maximize heat loss.

 

[mataxis]

Let me help a bit. Hybrids are divided into two architectures: (a) Parallel Hybrid and (b) Series Hybrid.

Parallel means the gas motor (it can be gasoline or diesel) runs in Parallel with the electric drivetrain to power the electric motors and charge the battery and has a mechanical connection to the road wheels. There are several sub-variations of the Parallell hybrid system.

A Series Hybrid means the gas engine operates to create electricity that powers the electric drive motors and charge the battery. The gas engine is not mechanically connected to the road wheels. It's called "series" because the engine-powered electric generator has to make electricity first before the car will move. Make electricity first means the generator either supplies the electric drive motors with power or charges the battery, or both. It appears the Harvester architecture will also be a PHEV (Plug-in Hybrid Electric Vehicle), which means it can be plugged in to a charger to charge the battery in advance of the engine-generator supplying power to the electric drivetrain. Once the battery reaches a predetermined level of energy depletion the engine-generator starts and begins powering the electric drivetrain.

So, the Harverster hybrid will be able to run indefinitely on the engine-generator as long as there is gasoline in the fuel tank. The impact that results is a lower overall eMPG (equivalent Miles-Per-Gallon) rating because internal combustion engines are not that effective turning the energy stored in gasoline (or diesel) into usable power. They are known in physics/engineering parlance as "heat engines", which results in the power converted during the combustion event in the cylinder being mostly lost as heat. But using a gas engine to generate electricity is more efficient use of gasoline (or diesel) because the EV drivetrain is very efficient and loses little heat as it converts energy in the electricity to motion.

Thank you so much for taking the time to explain that. So, it sounds like I’ll be a-ok to make the 700 mile trip without plugging in, which is a big relief. Love the design, bench seating, retractable roof, etc. but just needed to make sure it won’t make my monthly 12-13 hour journeys unbearable. Thanks again!

 

[Opus]

So here is a question. Say I run the battery to zero and the tank to zero. I fill it up with gas, but *don't* drive it. Can I basically park it and let the generator run to charge the battery up, while sitting, not draining the battery to drive the electric engines (say, it I park at a campground or hotel or whatever), then top off the gas and have the full 500 mile range when I get back on the road?

 

[Stumpy]

I'm hoping Scout does this right and uses a clean sheet design for the engine and generator. I hope the plans are not to repurpose a corporate VW car engine. Powering just a generator can allow for a more efficient combustion cycle and lighter weight engine to maximize heat loss.

That's my hope too, but I think little chance the Harvester engine won't be a VW engine. First, the decision to add an EREV model was made late in development, which means they likely just picked a VW engine off the shelf. Second, it'd cost so much more money to develop a ground-up in-house motor rather than picking an already existing VW engine.

 

[Efthreeoh]

That's my hope too, but I think little chance the Harvester engine won't be a VW engine. First, the decision to add an EREV model was made late in development, which means they likely just picked a VW engine off the shelf. Second, it'd cost so much more money to develop a ground-up in-house motor rather than picking an already existing VW engine.

Yeah, I see that point too and have thought about it (not just in the case of Scout), but there are several developed engine designs that can be licensed. Scout has three years ahead of them before launch. They have not said the EREV will launch at the same time as the EV. They can plan for it in production because the engine-generator will be a assembly module installed at a station on the production line. Scout has a lot of runway to develop a clean sheet EREV solution. I do not think it's going at the back of the vehicle. A laid-over 3-cylinder between the rear axle and bumper, with a generator attached? Eh, I'm not seeing how that's done.

 

[KarlT]

I'm hoping Scout does this right and uses a clean sheet design for the engine and generator. I hope the plans are not to repurpose a corporate VW car engine. Powering just a generator can allow for a more efficient combustion cycle and lighter weight engine to maximize heat loss.

‘maybe a Porsche engine?