EREV - A Horsepower Math Problem?

[Newton]

I saw someone quote the RamCharge, saying it has a 130kw generator. If some of the recent math is correct that you need 35kw ~ 70kw to keep driving at 70mph then this could be filling you up at twice the rate you are depleting.

I think what will be interesting is, as you say above, the range extender needs to know when to kick in and at what level to keep the battery. I can just imagine the Guess-o-Meter they will have to build to get that right!

There is no way that it is a 130kW generator. This is what a 100kW generator looks like (and it costs $100,000)

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[gregoryhcain]

They must use a shoe horn to fit it all I
In:
“
The generator in the new Ram 1500 Ramcharger (its official name) is an onboard unit rated at 130 kW.


This generator is not connected to the wheels; its sole job is to convert mechanical energy from the gas engine into electricity to either charge the battery or power the electric drive motors directly.


Key Technical Specs


The system is powered by a familiar engine, but it operates in a unique "series hybrid" or Extended Range Electric Vehicle (EREV) configuration:


• Engine (Range Extender): A 3.6-liter Pentastar V6.


• Generator Output: 130 kW (with a peak mechanical engine output of roughly 202 kW to ensure the generator can run at peak efficiency).


• Battery Size: 92 kWh (liquid-cooled).


• Total Range: Up to 690 miles (targeted).


• Fuel Tank: 27 gallons.


How it Works


Unlike a traditional hybrid (like a Prius or a Ford F-150 PowerBoost), the Ramcharger’s gas engine has no mechanical link to the wheels.


1. The V6 engine turns the 130 kW generator.


2. The generator sends that electricity to the 92 kWh battery or directly to the front (250 kW) and rear (238 kW) electric motors.


3. Because the engine doesn't have to shift gears or deal with varying road speeds, it can run at its most efficient RPM to keep the truck moving or charging, even while towing up to 14,000 lbs.


Power Outlets


The truck also uses its battery and generator system to act as a mobile power station for tools or homes:


• Total Outboard Power: Up to 7.2 kW.


• Bed Outlets: Includes both 120V and 240V plugs.”

 

[chriserx]

There is no way that it is a 130kW generator. This is what a 100kW generator looks like (and it costs $100,000)

I mean I get what you're trying to say, but between the trailer and 169 gal fuel tank it's a little hard to visualize the difference. Until you realize it's a 5.2L diesel engine. Most people can visualize that.

 

[Newton]

Here it is with the doors open. The blue cylinder is the important part, a very large and heavy alternator. For scale, look at the battery.

From what I have read I get the impression that the REV is 30kW , and even that is a big ask for a gasoline Pentastar V6. I would question the longevity of that system, although I'm a diesel guy so I suppose I am biased.

 

[grottomatic]

I think the EREV is an interesting concept, been done in a few ways before, namely the BMW i3 with range extender. For a truck with a described emphasis on towing, ford has to assure that it will not get into a low SOC/low power state during rigorous towing events such as Eisenhower/Vail Pass or other areas with multiple climbs and descents.

I assume Ford will need to have a generator that can feed the DC bus (not necessarily the battery) and motors at close to peak demand (200kW) without dropping SOC too much leaving the truck in a derate condition pulling a max load. Without a large genset, you could get into a condition where you did not have the SOC to pull a load at highway speeds if you did not start the climb without sufficient battery percentage, eliminating the advantage of an ERV. I suspect that Ford will need to run the generator 100% of the time in Tow/Haul mode to ensure SOC for climbs and Ford will force tow/haul mode anytime a 7 pin connector is detected.

This limits the engine/genset options for Ford - they might be able to use an ecoboost 4 such as the 2.3 in the ranger to supply 120kw-150kiw but the engine will be stressed and perhaps very noisy. An ecoboost 2.7 would do this easily at lower RPM and noise. I tend to think they will want a 4 for packaging but may need to use a 6, such as the 2.7 or 3.3NA to supply adequate genset power at peak load.

You will need to have a relatively large battery as buffer for max tow, if the motor can produce 120-150kw to the DC bus for the motors, then the battery will need to supply 70-50kw, sustained to generate 200kw (or more). This gives you an hour or less of max capability with a reasonable sized battery of 70-80kwh.

Running a motor at peak to feed the bus in max towing conditions will burn a lot of fuel, perhaps more than a ICE only truck given efficiency losses of the genset, DC bus, and electric motors. To hit "700 miles" the truck will have to have a considerably sized fuel tank - prob at least 25 gallons.

Dropping 50kwH of battery gives you some weight savings from the BEV, but enough for a genset and the capability to carry 25 gallons of fuel? and still have reasonable payload?

EREVs are a tough engineering problem. I'm surprised that they aren't doing this in a super duty platform to carry weight. It seems they may be approaching a 7500 lb vehicle.

This vehicle will also be very expensive - you get the full cost of the pack, genset and HV conduit, extreme cooling needs for what will become a very hot engine, battery, and electric motors.

Ford will need to make some breakthroughs that make this attractive to buyers at a reasonable cost.

 

[MrH42]

Here it is with the doors open. The blue cylinder is the important part, a very large and heavy alternator. For scale, look at the battery.

From what I have read I get the impression that the REV is 30kW , and even that is a big ask for a gasoline Pentastar V6. I would question the longevity of that system, although I'm a diesel guy so I suppose I am biased.

...what?

30 kW is not a "big ask" for a V6 pentastar. Do you not realize that kW is just a measure of power? 30 kW = 40 hp. Pentastars have been making 200-300 hp peak for over a decade. You'd want to optimize it for this use case, but 30 kW is not some sort of unachievable power output.

Generators for buildings are larger for a lot of different reasons (cooling, need to sustain output indefinitely, less focus on packaging efficiency, etc).

 

[Lomilar]

https://www.f150lightningforum.com/forum/threads/important-update-ford-ev-roadmap-future-of-f-150-lightning-erev-next-gen-model--admin-warning-no-politics.33426/post-618051

So the above states that you need half a Miata engine (80 hp) to keep the truck running on level ground with gas at 80mph forever. If you assume trailer (~halves the efficiency per Aging Wheels, thereby ~doubling the power requirement) and grade (halves the efficiency again per this, again, doubling the power requirement) then you need a peak horsepower of 80*2*2, or 320hp to be able to tow up a 5% grade using just gas forever.

However, not all grades last forever, and cabbage hill (one of the worst) is 7 miles at 6%. If you're able to store energy, you can target 50% energy and as long as you have ~28 miles in the battery, you can come out the other side and regen while generating to give you back those 28 miles in a hurry.

I think realistically a 200hp engine could handle this along with a 50kwh battery, but I haven't done the real engineering to figure out the actual answer here.

 

[VAF84]

I think the EREV is an interesting concept, been done in a few ways before, namely the BMW i3 with range extender. For a truck with a described emphasis on towing, ford has to assure that it will not get into a low SOC/low power state during rigorous towing events such as Eisenhower/Vail Pass or other areas with multiple climbs and descents.

I assume Ford will need to have a generator that can feed the DC bus (not necessarily the battery) and motors at close to peak demand (200kW) without dropping SOC too much leaving the truck in a derate condition pulling a max load. Without a large genset, you could get into a condition where you did not have the SOC to pull a load at highway speeds if you did not start the climb without sufficient battery percentage, eliminating the advantage of an ERV. I suspect that Ford will need to run the generator 100% of the time in Tow/Haul mode to ensure SOC for climbs and Ford will force tow/haul mode anytime a 7 pin connector is detected.

This limits the engine/genset options for Ford - they might be able to use an ecoboost 4 such as the 2.3 in the ranger to supply 120kw-150kiw but the engine will be stressed and perhaps very noisy. An ecoboost 2.7 would do this easily at lower RPM and noise. I tend to think they will want a 4 for packaging but may need to use a 6, such as the 2.7 or 3.3NA to supply adequate genset power at peak load.

You will need to have a relatively large battery as buffer for max tow, if the motor can produce 120-150kw to the DC bus for the motors, then the battery will need to supply 70-50kw, sustained to generate 200kw (or more). This gives you an hour or less of max capability with a reasonable sized battery of 70-80kwh.

Running a motor at peak to feed the bus in max towing conditions will burn a lot of fuel, perhaps more than a ICE only truck given efficiency losses of the genset, DC bus, and electric motors. To hit "700 miles" the truck will have to have a considerably sized fuel tank - prob at least 25 gallons.

Dropping 50kwH of battery gives you some weight savings from the BEV, but enough for a genset and the capability to carry 25 gallons of fuel? and still have reasonable payload?

EREVs are a tough engineering problem. I'm surprised that they aren't doing this in a super duty platform to carry weight. It seems they may be approaching a 7500 lb vehicle.

This vehicle will also be very expensive - you get the full cost of the pack, genset and HV conduit, extreme cooling needs for what will become a very hot engine, battery, and electric motors.

Ford will need to make some breakthroughs that make this attractive to buyers at a reasonable cost.

All of this just sounds terrible. Whether it’s a V6 Pentastar, or a 2.7 Turbo, who wants this? Those are power plants that already power full sized pickup trucks, and require all of the regular maintenance, expenses, inconveniences of an ICE vehicle. Then throw in the battery and all of its potential issues. Not to mention that if going the turbo route, that further increases complexity and failure points.

I still don’t think this moves the needle for the traditional truck buyer. A lot of old school guys will still not like that they can’t fix it themselves if something goes wrong, and new gen will want pure EV. The price is likely to be equal or more than pure EV with the extra hardware.

I love reading the technical aspects of this experiment, but the more I read, the less I believe you’re average Joe is going to sink their hard owned money into this.

 

[chriserx]

Here it is with the doors open. The blue cylinder is the important part, a very large and heavy alternator. For scale, look at the battery.

From what I have read I get the impression that the REV is 30kW , and even that is a big ask for a gasoline Pentastar V6. I would question the longevity of that system, although I'm a diesel guy so I suppose I am biased.

Based on my truck's power draw of ~54 kw at 80 mph, and the fact that trucks will occasionally tow stuff and be required to go up hill, I'd say the absolute minimum Ford could get away with here is 75 kw, but most likely to be rated for -100 kw. It's not a particularly big ask to fit a 5.2L engine into a vehicle that can already fit them. As far as the alternator goes, a long cylindrical one is probably the more efficient design, but it's not the only one. Even if they kept that design, they could face it toward the firewall and under the cab. Without the need for a transmission or drive axles there are actually quite a few options. If they went with a Mazda style rotary engine they could put it literally anywhere.

 

[Lomilar]

All of this just sounds terrible. Whether it’s a V6 Pentastar, or a 2.7 Turbo, who wants this? Those are power plants that already power full sized pickup trucks, and require all of the regular maintenance, expenses, inconveniences of an ICE vehicle. Then throw in the battery and all of its potential issues. Not to mention that if going the turbo route, that further increases complexity and failure points.

I still don’t think this moves the needle for the traditional truck buyer. A lot of old school guys will still not like that they can’t fix it themselves if something goes wrong, and new gen will want pure EV. The price is likely to be equal or more than pure EV with the extra hardware.

I love reading the technical aspects of this experiment, but the more I read, the less I believe you’re average Joe is going to sink their hard owned money into this.

I think everyone is way overestimating what kind of engine is required to make this work. You want an Atkinson cycle with zero turbos, something like the Duratec 4 or 6 cyl. You want an engine optimized for exactly one RPM, which it pretty much lives at. And you want somewhere between 200-320 peak hp (depending on how much battery you have) to support towing + grade.

All this means you can really optimize for durability and longevity, which you will have to, given how much the engine will be sitting.

 

[VAF84]

I think everyone is way overestimating what kind of engine is required to make this work. You want an Atkinson cycle with zero turbos, something like the Duratec 4 or 6 cyl. You want an engine optimized for exactly one RPM, which it pretty much lives at. And you want somewhere between 200-320 peak hp (depending on how much battery you have) to support towing + grade.

All this means you can really optimize for durability and longevity, which you will have to, given how much the engine will be sitting.

I'd like to think so (overestimating). I'm giving the Ford engineers some benefit of the doubt, since I doubt they'd create a replacement product that sounds objectively worse in most ways than what is being replaced. That is, unless this is being driven by exec's who don't have a lot of hands on technical expertise, haven't spent considerable time as truck owners, and haven't experience living with an EV.

 

[Lytning]

All of this just sounds terrible. Whether it’s a V6 Pentastar, or a 2.7 Turbo, who wants this? Those are power plants that already power full sized pickup trucks, and require all of the regular maintenance, expenses, inconveniences of an ICE vehicle. Then throw in the battery and all of its potential issues. Not to mention that if going the turbo route, that further increases complexity and failure points.

I still don’t think this moves the needle for the traditional truck buyer. A lot of old school guys will still not like that they can’t fix it themselves if something goes wrong, and new gen will want pure EV. The price is likely to be equal or more than pure EV with the extra hardware.

I love reading the technical aspects of this experiment, but the more I read, the less I believe you’re average Joe is going to sink their hard owned money into this.

Consider the Recalls, CSP's and TSB's of @Ford Motor Company's ICE F-150's. Consider the Recalls, CSP's and TSB's of the BEV components (i.e., non-overlap with ICE) of the F-150 Lightnings. Add them together. Then, throw in a few extra for the additional complexity of combining both ICE and BEV systems for the first time in a new vehicle.

How many existing F-150 ICE or Lightning owners are going to spend even more money for an even less reliable truck than they have now?

 

[PJnc284]

Consider the Recalls, CSP's and TSB's of @Ford Motor Company's ICE F-150's. Consider the Recalls, CSP's and TSB's of the BEV components (i.e., non-overlap with ICE) of the F-150 Lightnings. Add them together. Then, throw in a few extra for the additional complexity of combining both ICE and BEV systems for the first time in a new vehicle.

How many existing F-150 ICE or Lightning owners are going to spend even more money for an even less reliable truck than they have now?

We should have a recall drinking game when/if this all comes to fruition. Not sure i can afford or even handle that much alcohol.

 

[grottomatic]

I think everyone is way overestimating what kind of engine is required to make this work. You want an Atkinson cycle with zero turbos, something like the Duratec 4 or 6 cyl. You want an engine optimized for exactly one RPM, which it pretty much lives at. And you want somewhere between 200-320 peak hp (depending on how much battery you have) to support towing + grade.

All this means you can really optimize for durability and longevity, which you will have to, given how much the engine will be sitting.

Maybe. I think the hybrid Atkinson cycle engines are going to have a tough time supplying the truck in edge case conditions which is kind of why ford is in the situation it is in- the Lightning “failed” in fords eyes due to range collapse towing and in the cold.

if the go with a smallish hybrid engine then you will have a situation where you will be in a derated condition when towing grades. Edge case but important to theoretical buyers. I think if ford wants this to be a true towing machine then they have to have an engine able to supply the vast majority of power at peak demand.

if they actually build it- the genset will have to be substantial and will likely have multiple modes - standard output and a max output. To supply max output it may be better for a tuned turbo generator where it can produce massive power for heavy loads for short periods and standard output, likely somewhere out of boost, to just recharge the battery- out of boost. 2.7 would be perfect for this but packaging and price would be a nightmare. And at that point why not just build a traditional hybrid or small battery PHEV 2.7 that could have 40 miles or all electric range?

I don’t know if the economics work out but would be happily surprised to find out otherwise

 

[Lomilar]

Maybe. I think the hybrid Atkinson cycle engines are going to have a tough time supplying the truck in edge case conditions which is kind of why ford is in the situation it is in- the Lightning “failed” in fords eyes due to range collapse towing and in the cold.

if the go with a smallish hybrid engine then you will have a situation where you will be in a derated condition when towing grades. Edge case but important to theoretical buyers. I think if ford wants this to be a true towing machine then they have to have an engine able to supply the vast majority of power at peak demand.

if they actually build it- the genset will have to be substantial and will likely have multiple modes - standard output and a max output. To supply max output it may be better for a tuned turbo generator where it can produce massive power for heavy loads for short periods and standard output, likely somewhere out of boost, to just recharge the battery- out of boost. 2.7 would be perfect for this but packaging and price would be a nightmare. And at that point why not just build a traditional hybrid or small battery PHEV 2.7 that could have 40 miles or all electric range?

I don’t know if the economics work out but would be happily surprised to find out otherwise

I could see a 4cyl ecoboost to achieve better peak horsepower given a smaller footprint. That occurred to me after I wrote this.

Max tow isn't ever going to be a need for 320hp supplied forever though. You can also, in extreme edge cases (start at the bottom of a mountain with zero battery) pull over and generate, go slower than 80mph, or like... start it up and let it recharge itself.

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