EREV - A Horsepower Math Problem?

[ZeusDriver]

No one would disagree that ford nav leaves something to be desired. Doesn’t change the fact that an EREV could greatly benefit from route planner integration to address many of the issues raised in this thread.

I agree, although it seems like a said state of affairs. How many drivers leave from Kansas city for San Francisco without knowing anything about the topology? Granted, something like a majority of high school graduates cannot find Chicago on a map.

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[ZeusDriver]

Keep in mind that an EREV F-150 will have access to the route planner (read: elevation, weather data, etc).

it should be trivial for the future truck to plan to run the generator at a sufficient clip to keep sufficient battery through whatever the route plan is. Or, telling you if your route plan is not doable with the inputted variables.

that’s an advantage prior EREVs wouldn’t have had one would imagine.

I agree, although with my primitive little EREV, turning the charger on at appropriate times was incredible easy. Ditto for my Volt's Mountain mode.

Perhaps they cracked the code on resolving that

The code: Huge battery (90kWH in the RAM). Huge engine (3.6 liter). Huge weight. Mediocre fuel consumption. Astronomical Price. Huge profit. Happy oil companies.

If you go onto the RAM site and look at how they are positioning the RAM Rev, there are loads of luxury features illustrated. Not an everyman's truck at all. Ford would not do that, right? Just think about how easy it was to get the advertised 39,995 Pro Lightning. Every dealership had 20 on the lot with highly-trained sales people, all offering to sell at a steep discounts just to get the trucks out there to be seen!

 

[mr.Magoo]

To get the range & power Ford indicates (700 miles & say 12K-13K towing, probably uphill at 70 mph )

Except that they don't indicate it as being combined, or maybe you were being facetious and I missed it ?

 

[Jseis]

Except that they don't indicate it as being combined, or maybe you were being facetious and I missed it ?

Well. You got me on the uphill at 70. My read is that the hybrid will probably be a turbo V6 in the 4 liter range integrated with a variable speed motor drawing off battery & generator to give 600+ peak hp and 800? ft pounds torque. Or something like that. F1 uses some exotic power management systems integrating engine & motor-battery systems.

 

[mr.Magoo]

Well. You got me on the uphill at 70. My read is that the hybrid will probably be a turbo V6 in the 4 liter range integrated with a variable speed motor drawing off battery & generator to give 600+ peak hp and 800? ft pounds torque. Or something like that. F1 uses some exotic power management systems integrating engine & motor-battery systems.

I suppose my command of the English language and reading comprehension have been criticized before, but the way I read their statement (and usually how marketing/specs are written) is that it's all isolated circumstances.

The current Lightning ER have a 320mile range during an synthetic EPA cycle.

They're not changing their measuring stick to include much higher speeds and towing a giant trailer.

If we're still talking about the NG Lightning, it's an EREV, not a Hybrid.
The engine won't have any mechanical connection to the wheels (some will argue that cables are mechanical, just because this is the internet, but I mean driveshaft, etc.).

It'll be interesting to see what they end up with, I don’t think there's any facts on the matter just yet (the thing is 2-3 years out).
But personally I see a 60-75kWh battery and ~50kW generator coupled with a 1-1.5l 3-cylinder, purpose built, engine and say a 20 gallon full tank, personally I'd pick diesel, but I don't think that'll happen in the US market.
With this the generator would be able to keep up with highway speeds (not towing) at around 35-40kW, and get a reasonable runtime of, say 4hrs plus battery, so all in all around 400 miles at highway speeds, higher if you go slower (EPA cycle).

But again, this is all a shot in the dark for everyone since there isn't any official information out there.

 

[hturnerfamily]

let's think about this supposed '700 miles of range', in a rational calculation:

and let's assume the battery pack is rated at an EPA 350 miles range(just as an example)

- this means that the Generator(the engine output) will be able to create the ADDITIONAL 350 miles of range, on it's own... meaning that it is producing the SAME amount of KW of power back into the battery pack to meet that same EPA rating, AS YOU ARE DRIVING, before it runs out of fuel.
We don't know exactly how they arrived at that EPA standard rating, such as the SPEED of the vehicle, or the TERRAIN, or the TEMPS, or the WIND, but it most likely certainly would NOT include TOWING of any sort, or any additional weight in the truck, such as 5 passengers, etc.


ADD YOUR ANSWERS:
- if we assume that the battery usage for the EPA rating is, for example, 2.5mi/kwh, then the calculations are: 350 miles / 2.5 miles = 140 kWh battery pack.
- if you drive conservatively at the EPA 55mph for that WHOLE range, you will drive for 6.37 hours.
- if the Generator engine needs to then produce that same kWh of power, over that same 6.37 hours, it will need to output 240v @ ________ the WHOLE time.

obviously we can all admit that 350 miles range ain't gonna happen, not if the idea of the EREV is to use some of the battery pack space for an area for the generator's fuel tank, and to lighten the load and lower the cost.

let's use a more REAL WORLD example:
- a 100kwh battery pack
- now, averaging that EPA 2.5mi/kWh, we can assume the battery might get us 250 miles, downhill, on a good day... but we also know that a 100kwh battery pack does not give us 100kwh of USABLE power, but more likely 95. That's then a 'range' of 237.5 miles, very similar to the EPA rating of my '22 PRO SR, with 240.
- if the Generator engine needs to then produce that same kWh of power, over that same 6.37 hours, it will need to output 240v @ ________ the WHOLE time.


While it's unlikely that ANY owner, especially us EV owners, would want a generator/engine to be running the WHOLE TIME we are driving, these are also just EPA estimates of what COULD BE POSSIBLE, at best, in those 'average' conditions. It probably bears little meaning in the 'real world'.

Most of us would probably assume that an EREV would only need the generator in 'critical' conditions... such as when you only need that 'few' extra miles of range, and when you might then simply turn the generator ON near the end of the journey.

It sounds like that's more of a pie-in-the-sky idea, and more of a real 'turn the generator ON as soon as you first start'...

this reminds me of my wife's '22 KIA Sorento PHEV... she could certainly drive in EV ONLY mode, for up to the first 30 or so miles, but, of course, the engine would start up then for the rest of the trip. OR, you could start the engine from the GET GO, and save the battery miles until the END of the trip, or maybe to use in inner-city stop-n-go driving, etc. It was always a toss-up, because you don't really know 'when' to turn the engine off, unless you know EXACTLY how many miles are left to drive, etc... it's mental gymnastics, and something that most folks don't want to deal with.
I'm sure software will provide a much better option, but, even then, you will have to CONSTANTLY be cognizant of when to stop for FUEL, or when to stop for POWER, or both... we EV owners might be understanding of that, but I'll doubt new owners will understand the constant calculations and planning required... or they'll stop only at gast stations, just like they always have.

On another note: even if the generator ENGINE output can provide power DIRECTLY to the motors, as some have suggested, this still uses FUEL, and therefore is going to essentially drain the engine's fuel tank at a similar rate - the range would not change.

 

[mr.Magoo]

let's think about this supposed '700 miles of range', in a rational calculation:

I would refrain from using volts in your calculations/assumptions as we can pretty much guarantee that the onboard generator will not be 240V. It'll most likely be matched to the pack voltage, or at least 400V if they end up with a 800V pack (higher voltage would create insulation challenges, so I'm not sure how far they'd take it), to minimize conversion losses and also reduce cable size (cost/weight) - that plus the fact that a kW is a kW regardless if you have 1V or a 1000V.

 

[chriserx]

We don't know exactly how they arrived at that EPA standard rating, such as the SPEED of the vehicle, or the TERRAIN, or the TEMPS, or the WIND, but it most likely certainly would NOT include TOWING of any sort, or any additional weight in the truck, such as 5 passengers, etc.

Unless I'm misinterpreting, the EPA test cycle is known.

https://www.epa.gov/greenvehicles/fuel-economy-and-ev-range-testing

https://www.ecfr.gov/current/title-40/chapter-I/subchapter-Q/part-600/subpart-B/section-600.116-12

and let's assume the battery pack is rated at an EPA 350 miles range(just as an example)

I realize you stress 'as an example', but did you sanity check this? My BEV L doesn't even get close to this.

if the Generator engine needs to then produce that same kWh of power, over that same 6.37 hours, it will need to output 240v @ ________ the WHOLE time.

It would more likely be at the pack voltage and not the L2 voltage, but the answer is 22 kw, or using your setup 91.7A

But I agree with your basic premise, EPA test cycles are decent for gas vehicles but way too optimistic on EVs. I personally estimate a usable pack size of 50 kwh (2 hours at 55 plus change) and a generator output of 100-250 kw continuous. 100 if they go with efficiency and 250 for high performance applications

 

[Deleted member 19221]

It's going to weigh 9000 lbs.

 

[hturnerfamily]

"I realize you stress 'as an example', but did you sanity check this? My BEV L doesn't even get close to this."
Exactly - I was just trying to simplify the 'math' using an example where 1/2 the miles are from the battery, and the other 1/2 from the generator/engine... some EV's do, though...

"It would more likely be at the pack voltage and not the L2 voltage, but the answer is 22 kw, or using your setup 91.7A"
I'm trying to wrap my brain around some type of 400+volt generator... give me some examples of some, especially something that would fit in the frunk area.

"But I agree with your basic premise, EPA test cycles are decent for gas vehicles but way too optimistic on EVs. I personally estimate a usable pack size of 50 kwh (2 hours at 55 plus change) and a generator output of 100-250 kw continuous. 100 if they go with efficiency and 250 for high performance applications"
Why would you assume such a much smaller size of battery pack, especially one on an EV Truck?... this would seem to defeat the whole purpose of the platform.
I would like to see, too, some examples of some 100-250kw continuous Generators... it seems like a very tall order for a vehicle.

RAM says that they are using the 3.6L Pentastar® V6 engine with a liquid-cooled 92-kilowatt-hour battery pack paired with a 130-kilowatt generator.

 

[mr.Magoo]

and a generator output of 100-250 kw continuous. 100 if they go with efficiency and 250 for high performance applications

So something like this ?

 

[P-38]

The engine won't have any mechanical connection to the wheels (some will argue that cables are mechanical, just because this is the internet, but I mean driveshaft, etc.).

Well you see...the engine sits on motor mounts which attach to the frame and the frame is attached to the wheels thru various parts so there 100% is a mechanical connection...

 

[Lytning]

I honestly don’t understand the “importance” of how the ICE is “connected” to the wheels. The ICE is physically connected to the generator, and is the only source of power to drive the generator. Whether the generator output flows through the HV battery, or somehow bypasses the HV battery, when the HV battery is at its minimum allowable SOC, the ICE-driven generator will be the only source of power to the wheels. And that is why the size of the ICE and generator matter so much.

 

[Newton]

Plenty of pure battery EVs get more than 350 miles of range, including the Silverado (492) and the Lucid (512). It won't be too long before that is the range that we all expect - I was super happy that my 2019 e-Golf got a rating of 120 miles which is now pathetic.

Voltage is not the issue for a generator, a Van de Graaff generator is a simple mechanical device that can generate thousands of volts at a very low current. The issue is the kW rating, and the electric motors that drive trucks can consume 500 kW in larger vehicles such as the Silverado - and you usually have two of them. If you want a generator that can do this for any length of time, it has to be a large block diesel with a lot of torque at the low end. In addition, the alternator that converts mechanical to electrical energy has to be very large with a bunch of copper in the windings and lots of metal to dissipate the heat.

So that is the technical challenge that you have to overcome in an EREV. If you had a pure diesel electric (no battery) such as a train the generator would have to be impractically large for a light truck. In any case, a diesel would probably be at least as expensive as simply adding batteries, but the cheaper gasoline engines are not really suited for large generators - they die quickly. Charging the batteries with a lower power generator while running doesn't really help the user because you will still eventually run out and have to go to the dreaded fast charger. In the mind of the scared EV novice, running out after 500 miles is just the same as running out after 80 miles.

The only hint I see of this future is Fords recently released EREV Bronco in China which apparently solves the problem by simply having poor performance when it is running on generator-only. It feels a little deceptive to talk about a "758 mile range" when many of those miles have much less performance than when the battery is running. I do not know how bad it is, but someone who is used to driving 85 will be pretty unhappy once their top speed is limited to 50 until they go to the dreaded fast charger.

Obviously the engineers will try to do something better than that but they run into a fundamental problem - converting mechanical energy to electrical energy and then back to mechanical energy is going to be less efficient than the already inefficient mechanical ICE arrangement. (One real design issue for generators is heat dissipation in the alternator - and that heat represents energy loss.) If you are limited to the same size of engine that the ICE truck has, you are going to have less power than the equivalent ICE when you are in generator mode. If the solution is to have two levels of performance, I do not see how this satisfies the truck user. You don't want to lose power after you have driven your trailer 100 miles to the mountains.

 

[Newton]

In the end, I think that the EREV is a psychological (and political) solution rather than an engineering one. I have met people in California who are as surprised that I'm coming from Canada in an EV as if I told them that I had walked. They don't know that compared to my EV6 the Lightning has pathetic range and a glacial charging rate, but it is more comfortable so we take it on long trips. These are the people that Ford is halfheartedly trying to convert, and I'm kind of worried that they will have a worse experience than those of use with pure EVs. That may be the point, though...

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