The “range–extended” EV (BEVx) considered

[Ingineer]

I'd have to think a single 24kw unit would be more efficient, and cheaper.

I agree. Turbine efficiency goes up with size, so the bigger the better. It would also be lighter weight overall.

The Capstone unit I am using was never weight-optimized for mobile use, it was designed for cogen applications in the basements of large buildings. Still, it's not all that bad, but it's enough that it would be hard to hang off the back of the Leaf without having suspension upgrades. This is why I made it into a standard 2-wheel trailer. It also makes it vert easy to detach and roll around, which is handy considering It's dual-role as both a range-extender and a mobile quick-charger.

-Phil

 

[evnow]

It also makes it vert easy to detach and roll around, which is handy considering It's dual-role as both a range-extender and a mobile quick-charger.

If someone were to manufacture this commercially in large (as in a thousand ?) numbers, how much do you think each could be sold at ? Just wondering if there is a possibility of something like this making it to the market.

 

[Herm]

If someone were to manufacture this commercially in large (as in a thousand ?) numbers, how much do you think each could be sold at ? Just wondering if there is a possibility of something like this making it to the market.

The typical ICE engine costs the manufacturers less than $500, and (IMO) they are far more complicated.

 

[dznit]

Maybe a national rent a car company would be interested in renting the turbine trailer when a Leaf needs to go cross country!

 

[edatoakrun]

Back to the original intent of this thread, If you could just buy this as an option on a on-road BEV...

...Facundo had the idea to develop a Go-Kart with range extender, a 4stroke 160cc engine that develops 5.5ch provides electricity the batteries once they are depleted.

The real engine that drives the wheels is an electric motor of 5.5kW and 30Nm, offering one hour of range on the batteries and up to 4 hours in combined mode (despite the small gas tank of only 4l).

At night, batteries can be recharged in 6 hours on the 220V...

http://www.technologicvehicles.com/en/green-transportation-news/1482/facundo-elias-develops-a-range-extender-go-ka" onclick="window.open(this.href);return false;

When searching for this thread, I found adric22's earlier thread, with a very similar OP.

...So, lets examine how that would work. Lets say you need to drive further than the usual limit of the Leaf's battery. You could tell it to turn the range extender on at the beginning of the trip and it would be charging while you drive. Sure, you are still going to deplete the battery but it might add 15 or 20 miles of range. Then, when you park at your destination, it would keep running and recharging your batteries. After a few hours, you return to your car and you've gained 20 or 30 more miles of range. You could, in theory, add more fuel on the go if need be.

Now, I'm sure this idea sounds silly to a lot of people, because they want an EV, not a hybrid. And the people that want a hybrid want to be able to drive on gasoline for really, really long trips. But, if such an option could be added to the Leaf for, say, $2,000 or less.. that could be an attractive option to people who drive a bit further than the regular range of the car, and I dare say it would get very good fuel economy. Because it would be so small, it could fit into the hatchback area and probably add only a small amount of weight to the car...

http://www.mynissanleaf.com/viewtopic.php?f=8&t=6065" onclick="window.open(this.href);return false;

Just wanted to give credit, and to mention that I didn't (consciously) plagiarise your thread, adric22.

 

[rmay635703]

Although this behemoth is massive

http://www.generatorsales.com/order/Isuzu-15000-Watt-Diesel-Generator.asp?page=1500TS" onclick="window.open(this.href);return false;

Calculations state that you should get about 56mpg @ 55mph. (about 75mpg @ 35mph using a dumb DC head instead of the AC one) Not sure how you would slug 800lbs behind the back very efficiently however. (the weight alone would probably add an eff loss of 10%)

Maybe a composite aero trailer with hard rubber tires, with swings/rockers & isolators under the genset.

At over $6k its still probably cheaper than a bigger battery and you can use it to run your house in a power outage.

The other solution (which is probably more reasonable weight wise) is this one
http://www.generatorsales.com/order/yanmar_4kw.asp?page=yanmar_4kw" onclick="window.open(this.href);return false;
89mpg @ 29mph but obviously it can only extend your range or drive your car down the road at 29mph. But 165lbs might be sluggable off a trailer hitch mounted rear rack.

Ingineer any hard specs like weight, fuel consumption per watt, etc on your rig? Do you have a thread somewhere on it?
(I see the other thread now but no KW per gallon info)

My thought is still to keep it dimensionally small, even if it is only 10kw or 14kw since it appears to me 55mph = 12790 watts or so (at least per this chart http://www.mynissanleaf.com/viewtopic.php?f=31&t=4295&hilit=+range+chart" onclick="window.open(this.href);return false

So do they offer a 10kw turbine?

 

[TonyWilliams]

55mph = 12790 watts or so (at least per this chart....

On level ground... Go up.a little hill and see how fast 12.79kW takes you up a hill !

 

[Herm]

Thats why you want to drive a bit slower than your max, so that the 12.79kW will slowly build up a buffer in your battery.

 

[edatoakrun]

55mph = 12790 watts or so (at least per this chart....

On level ground... Go up.a little hill and see how fast 12.79kW takes you up a hill !

That's why BEVs have batteries.

So you won't have to lug around a large, heavy, expensive, and inefficient, generator.

Someone should have mentioned this to the Chevy Volt designers, IMO.

 

[Ingineer]

There is a very good reason to add a generator that is at least capable of putting out what the average draw on the highway is. Anything less and you don't have unlimited range, you'd have to stop and/or slow down to allow charge recovery. In addition, you'd be reducing efficiency even further with extra conversion loss to/from the battery. This also would seriously exercise your battery, which might result in high temperatures and reduced life. Nissan could void your warranty over this pretty easily, as it's obvious that it's stressing the battery more.

The Capstone Microturbine generator can put out up to 30kW which will keep the Leaf on the highway indefinitely even at faster cruising speeds, and in addition will allow a reasonable amount of battery recharge while underway if desired. At most typical inter-city highway speeds, the Leaf is pulling over 20kW average. If you had a smaller generator, you'd have to slow way down and/or stop often.

The design goal was to allow a reasonable trip, such as from San Francisco to Los Angeles, and allow one to travel at the standard prevailing speeds most cars do. Anything less, and why bother with all the hassle?

The weight of the prototype is presently under 500lbs, and it feels almost "invisible" to the driver. It can be unhooked from the Leaf in mere seconds once you arrive at your destination to avoid the extra hassle of parking and driving in city areas. You also don't lose luggage capacity which is important on a trip.

-Phil

 

[hill]

If you could generate for 3 hours that would be 18kWh and almost double the battery. 150 miles seems reasonable at 50/55 mph.

Are you saying, one would start the genset as soon as the trip starts with a fullly charged Leaf ?

At 5 m/kwh, I think we can get 150 miles, in that case. But, I'd say 60 mph is the minimum for inter-city travel. . . . . o. . . snip

'60mph is the Minimum'? Last time I checked, many, if not most freeways say MAX speed pulling a trailer is 55.

With raised tire psi, flat ground, no wind, my Leaf's kw meter seems to read appx 6kw's being used at about 55mph. If you've ever driven CA's highway 1, with all the looky-lou's you're doing WAY less than half that speed. My EU6500 Honda gen/inverter would cover the 55mph, speed, if the Leaf is only pulling an average of 5kw-6kw's at 55mph. Even if our EU6500 is loosing a couple kW's while traveling ... it's range would be more significant than my hinie can tolerate sitting ... so that works too. Our EU6500 is normally just sitting under a cover, waiting for power to go out. At least with the Leaf now, the scheduled maintenance run times necessary on the generator can go to recharging the car.

.

 

[palmermd]

With raised tire psi, flat ground, no wind, my Leaf's kw meter seems to read appx 6kw's being used at about 55mph. If you've ever driven CA's highway 1, with all the looky-lou's you're doing WAY less than half that speed. My EU6500 Honda gen/inverter would cover the 55mph, speed, if the Leaf is only pulling an average of 5kw-6kw's at 55mph. Even if our EU6500 is loosing a couple kW's while traveling ... it's range would be more significant than my hinie can tolerate sitting ... so that works too. Our EU6500 is normally just sitting under a cover, waiting for power to go out. At least with the Leaf now, the scheduled maintenance run times can go to recharging the car.
.

There is something wrong with your numbers. If you use a 21kWh pack at 6kW rate it will last for 3.5 hours. If you drive 3.5 hours at 55 you will have gone 192.5 miles. Your Leaf has some incredible range! I think the rate at 55 is closer to 12kW which would last for 1.75 hours giving a range of 96.25 miles.

 

[hill]

There is something wrong with your numbers. If you use a 21kWh pack at 6kW rate it will last for 3.5 hours. If you drive 3.5 hours at 55 you will have gone 192.5 miles. ......snip

I'll check driving home and see what the readout says. But for me, the 96+ mile range is par for the course, w/out a range extender. At 10 months and 10,000 miles, we're averaging 5.0 miles per kWh at the wall (50/50 mix, freeway & city driving).

 

[EVDRIVER]

There is something wrong with your numbers. If you use a 21kWh pack at 6kW rate it will last for 3.5 hours. If you drive 3.5 hours at 55 you will have gone 192.5 miles. ......snip

I'll check driving home and see what the readout says. But for me, the 95+ mile range is par for the course, w/out a range extender. At 10 months and 10,000 miles, we're averaging 5.0 miles per kWh at the wall.

I would doubt the accuracy of any number read from the LEAF.

 

[hill]

There is something wrong with your numbers. If you use a 21kWh pack at 6kW rate it will last for 3.5 hours. If you drive 3.5 hours at 55 you will have gone 192.5 miles. ......snip

I would doubt the accuracy of any number read from the LEAF.

I agree ... but as long as the Leaf's odometer, and my clamp-on amprobe are dialed in, I should be good to go.
.

 

[Ingineer]

'60mph is the Minimum'? Last time I checked, many, if not most freeways say MAX speed pulling a trailer is 55.

With raised tire psi, flat ground, no wind, my Leaf's kw meter seems to read appx 6kw's being used at about 55mph. If you've ever driven CA's highway 1, with all the looky-lou's you're doing WAY less than half that speed. My EU6500 Honda gen/inverter would cover the 55mph, speed, if the Leaf is only pulling an average of 5kw-6kw's at 55mph. Even if our EU6500 is loosing a couple kW's while traveling ... it's range would be more significant than my hinie can tolerate sitting ... so that works too. Our EU6500 is normally just sitting under a cover, waiting for power to go out. At least with the Leaf now, the scheduled maintenance run times can go to recharging the car.

I concur with the assessment that you must be mistaken about these numbers. There is no way you can go 55mph and only consume 6kw unless you are driving down a steep hill!

In order to use an EU6500 or any other AC output generator, you will need a power supply that can take the AC in and put out around 400 volts DC, and it must be isolated from the chassis. This is non-trivial to implement, and will also lose some power in the conversion.

I would not trust your clamp-on meter to accurately gauge power consumption. It is difficult on this type of ammeter (hall effect) to have good accuracy without often recalibrating. (rezeroing) In addition, even if you have accurate current instrumentation, it doesn't give you a complete picture, as you don't have the voltage which is needed to calculate real power (wattage). The gauge on the energy screen is reasonably accurate, and checking it while on the highway will reveal the true picture.

I run my tires at close to 50psi and find that 20kW is a good figure for my freeway driving (obviously over 55mph). If I'm going to be using a range-extender, I'll likely be on a longer trip between cities, and will be travelling at ~70mph, so I'd want it to be able to be at least capable of the average power consumption so I can make the trip and still arrive with some charge to get around. If the range extender is only going to be used for shorter trips that exceed the normal range, then it could be much smaller, but then you wouldn't ever be able to take a long trip.

-Phil

 

[edatoakrun]

For the 30 kW fans, another entry:

KSPG shows new compact two-cylinder range extender for EVs, variable valve system

...The new power unit consists of a two-cylinder, 800 cc V-type gasoline engine with a vertically positioned crankshaft and two generators with gear wheel drive. The use of two generators (2 x 15 kW) serves to provide balance for the two-cylinder V-configuration to help to reduce NVH (noise, vibration and harshness) from the engine—especially important in a range-extending application for a battery-electric vehicle, which normally is quiet.

The system also includes FEV’s Full Engine Vibration Compensator (FEVcom), which has been designed into the range extender to reduce NVH. With FEVcom, a reduction in the engine vibration of more than 95% at the engine mount could be measured in various engine applications, according to FEV.

KSPG sized the output to 30 kW, said Dr. Hans-Joachim Esch, Chief Technical Officer, based on the need for the target A-segment vehicle “to be faster than a truck”. KSPG analysis found that 26 kW was sufficient to move the car up a grade of 3% at 100 km/h; they chose 30 kW....

The range extender weighs a little more than 60 kg, together with the generators and all related parts...

http://www.greencarcongress.com/2012/01/kspg-20120111.html

Wonder what a 10 kW version would weigh?

 

[edatoakrun]

So, it looks like CARB has named this concept the BEVx, and got it partially correct, IMO:

...Staff expects BEVxs to play a longer-term role than TZEVs [ transitional zero emission vehicle; most commonly a plug-in hybrid PHEV] because of their improved zero emission mileage potential. These vehicles would be particularly well suited to use of low upstream GHG fuels that might be more expensive, since the predominant operating cost would be offset by relatively low-cost electricity. In addition to potential for emerging alternative fuel use, there is an opportunity to explore engine technologies that are advantageous but otherwise unsuitable for application in conventional vehicles.

Engine technology applied to existing PHEVs is derived from small conventional production gasoline engines, but highly specialized APUs for BEVxs may eventually spin off and evolve in completely different directions. Future BEVxs with highly specialized engine and fuel technologies could be optimized to drive cost, weight, size, and emissions down and make these specialized BEVx APUs suitable for more affordable and therefore more widespread application. Lotus Engineering and other automotive design firms have been developing hybrid-specific APUs and have several unique concepts under development already...

...It was suggested during the hearing that such a vehicle might even deliver more all-electric miles than a battery-only electric vehicle, as the availability of the range-extending engine could preclude drivers reserving battery charge to ensure they actually make it home.

The BEVx would have reduced performance while operating in APU (auxiliary power unit) mode—i.e., while using the range extender to find a charging location. Most of these vehicles are expected to have a zero-emission range of 80 miles or greater...

This vehicle has substantially more range than currently announced PHEVs, ARB staff noted, with electric range comparable to full function BEVs and will probably require ground-up BEV design...

But CARB is wrong, IMO, if, as suggested, it requires that the driver be prevented from engaging the engine before discharging the battery, limiting the RE engine use to “limp-home” mode, only:

...ARB staff suggested that the BEVx market may appeal to drivers who would not otherwise consider a BEV with the same range. Since staff considers these vehicles full function BEVs with short range APUs, it stressed the importance of having the minimum range for eligibility be equivalent to full function BEVs in the marketplace.

Basic criteria for these vehicle include:

1. the APU range is equal to or less than the all-electric range;

2. engine operation cannot occur until the battery charge has been depleted to the charge-sustaining lower limit;

3.a minimum 80 miles electric range; and

4.super ultra low emission vehicle (SULEV) and zero evaporative emissions compliant and TZEV warranty requirements on the
battery system...

http://www.greencarcongress.com/2012/01/bevx-20120129.html" onclick="window.open(this.href);return false;

 

[davewill]

But CARB is wrong, IMO, if, as suggested, it requires that the driver be prevented by engaging the engine before discharging the battery, limiting the RE engine use to “limp-home” mode, only:

...ARB staff suggested that the BEVx market may appeal to drivers who would not otherwise consider a BEV with the same range. Since staff considers these vehicles full function BEVs with short range APUs, it stressed the importance of having the minimum range for eligibility be equivalent to full function BEVs in the marketplace.

Basic criteria for these vehicle include:

1. the APU range is equal to or less than the all-electric range;

2. engine operation cannot occur until the battery charge has been depleted to the charge-sustaining lower limit;

3.a minimum 80 miles electric range; and

4.super ultra low emission vehicle (SULEV) and zero evaporative emissions compliant and TZEV warranty requirements on the
battery system...

http://www.greencarcongress.com/2012/01/bevx-20120129.html" onclick="window.open(this.href);return false;

I think the reason for that is to keep more traditional hybrids from qualifying as BEVx...It's certainly not required that the car actually "limp" when in charge sustaining mode.

 

[TomT]

And with that I concur; they shouldn't.

I think the reason for that is to keep more traditional hybrids from qualifying as BEVx...