Explained: EREV, Hybrid (Series vs. Parallel), PHEV in the Scout

An EREV is a Series-Hybrid. EREV is a marketing name conjured up because most non-technical people don't understand there are two types of hybrid vehicles: Parallell Hybrid (i.e. Prius) and Series Hybrid (i.e. Volt* or BMW i3).

*the Volt was unique in that its transmission could switch to parallel hybrid operation under specific circumstances.

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

Parallel Hybrid 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.

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.

Thanks for that detail.

Question: Say theoretically you are out in the wilderness and manage to completely deplete both the batteries and the gas generator.

Could you fill up the engine with gas from a can, and just take off again? Or would the generator have to run a whole to first charge up the batteries a little?

Taghkanic said:

Thanks for that detail.

Question: Say theoretically you are out in the wilderness and manage to completely deplete both the batteries and the gas generator.

Could you fill up the engine with gas from a can, and just take off again? Or would the generator have to run a whole to first charge up the batteries a little?

Click to expand...

While we would obviously need to wait for clarifications or independent test once the vehicle is released. I would imagine as long as you have gas for the generator the vehicle will be able to continue to drive. My PHEV has a buffer built in.. So Zero battery charge on the gauge is really 10%

Taghkanic said:

Thanks for that detail.

Question: Say theoretically you are out in the wilderness and manage to completely deplete both the batteries and the gas generator.

Could you fill up the engine with gas from a can, and just take off again? Or would the generator have to run a whole to first charge up the batteries a little?

Click to expand...

It depends on how the driveline is configured and how Scout plans on implementing the Harvester system, but in theory such a system just needs gasoline (or diesel) to create electricity and power the electric drivetrain.

Taghkanic said:

Thanks for that detail.

Question: Say theoretically you are out in the wilderness and manage to completely deplete both the batteries and the gas generator.

Could you fill up the engine with gas from a can, and just take off again? Or would the generator have to run a whole to first charge up the batteries a little?

Click to expand...

TLDR: Check out the Audi RS Q e-tron Hybrid Dakar Race car
https://www.caranddriver.com/reviews/a39851967/audi-rs-q-e-tron-hybrid-race-car-first-drive/

We don't yet know and it depends. What you're asking boils down to the law of thermodynamics. If Scout puts a beefy ICE motor then what you're asking about is perfectly reasonable as long as the battery was not at a dead 0%. If the motor is undersized then performance will be limited until the battery can be charged up enough.

Here's an example. The upcoming Ramcharger is using the 3.6 pentastar for multiple reasons, for this we will ignore the availability and reliability of the engine. The 3.6L has enough power to move the truck at normal speeds if it was connected straight to the wheels. While the truck would not have its normal 663HP capabilities, it would be able to charge the battery while you continue to make progress.

In the end it all comes down to Kilowatts. If you want a 1:1 power comparison, they will need to put in probably a turbo 6 cylinder at the very least in order to get the power required to never have a dip in performance.

Here is the most likely scenario based on cost and size. They will probably put a 4 cylinder engine in these trucks, then the engine will kick on when the battery dips to a certain percentage to charge it up. If the electric motor is not working hard, say on the highway when driving at a constant rate, then the little 4 banger will be able to outperform the electric demands. If you're pushing it REALLY hard then you will need to charge up first, then slow down.

With a four banger in this case and you run the battery down to safety shutoff then I would think you would have to gas up and let the generator run for awhile to get back on the move, how long would depend on several things, generator output, battery charge rate, and DOC needed to resume
Traveling. I wouldn’t think the generator would be more than a 4-6 KWh.

This is a good discussion about the Harvester.