I’ve been converted to the school of thought that an ICE range extender should mechanically drive the wheels instead of generating electricity. So, has anyone employed a motorcycle engine for such a purpose? I’m thinking that some of the smaller displacement options might make for a decent option.
For example:
A liquid-cooled 250 CC rated at about 29 HP.
http://www.kawasaki.com/PRODUCTS/detail.aspx?id=263&content=specifications
I remember reading (somewhere) about “Helper Motors” and Hybrid Upgrades that used Electric motors that were attached to the driveshaft(s) to augment the ICE - much in the same manner as Honda’s IMA system works… I don’t see why it wouldn’t work for another ICE as well… There would be a juggling act to play in terms of throttle control / balance… You’d have the same issue with an electric motor though… If I find the article/s I was reading I will repost here…
The only probs I can see with that is that bike motors generally achieve high HP figures for small disp through RPM, and fuel efficiency isn’t very good at high rpms. They are high MPG because they’re only pushing a bike, but if you were pushing a car you would be using almost full throttle on that little thing and be up in the revs.
Not saying it couldn’t be done, def not saying it wouldn’t be worth a try, but there are things to consider when making a judgement on which one to use. My Yamaha R1 only gets 40 mpg on the hwy! But that’s because it’s revving at 5k the whole time. If I’m beating on it around town it still gets about 30 so you can see the differences in high rpm low throttle and high throttle aren’t very big.
It definitely seems that picking an engine would be the tough part of an ICE. the best option, engineering-wise, likely would be to wait for the plug-in Prius or some other such product to come out, but it’s annoying to have to keep on with the 30-mpg vehicle I’m driving now.
I’d suggest considering it as an electrical generator. The advantage to this is, you know what RPM the generator must be turned at.
An ICE driven vehicle has a motor that must move the entire mass of the vehicle, at all speeds, including moving that mass from a dead stop. It must also be able to accelerate that mass from any speed to any speed.
A generator, on the other hand, must be run at one RPM. No matter what the electrical draw is, the generator needs to be turning at that one RPM. The electric motor does all the work to move the mass and must operate at all RPMs, but the generator ONLY operates at the one RPM.
Therefore, instead of moving the mass, the ICE (be it lawn mower, motorcycle, or car) that is used to run that generator can be optimized to run at that one RPM. There’s no load on till it gets there, and there’s no need for it to go faster, so the engine can be designed to run max efficiency at the specified RPM, regardless of the impact at idle or max RPM. And, through the magic of gearing, you can actually optimize the ICE to run at its max efficiency at whatever RPM it might be regardless of the generator’s need, then regear the connection between the two so that when the ICE is running at its most efficient it’s turning the generator at its required speed.
Running an ICE as a mechanical range extender though, requires that the ICE be optimized for multiple RPMs, and be capable of accelerating the mass. This cuts down on the efficiency, and complicates the installation since the ICE must now be installed where it can turn a wheel. This is easier if you set it up as a pusher trailer, but then the connection between the two needs to be very carefully designed, and if you have a unibody car you’ll need to reinforce the car body so as to not damage it.
Unibody cars have no frame and depend on the body of the car for structural support, and are not designed to take motive force from any point other than where the drive wheels are. You can’t even change tires on a unibody without using the designed jack points without damaging the car.
Hope this helps some.
Telco, your argument is exactly what had me thinking generator in the first place – optimizing a motor to run at a specific RPM and load seems like it would be more efficient than an ICE having to push a vehicle around.
Also, it seems like a smaller motor with proper gearing would be able to suffice for generation – maybe even a 50 CC scooter motor (though that might be overly optimistic).
But nearly all the posts I’ve seen argue against an ICE generator producing electricity.
(And before any naysayers jump to respond, I’m aware that an electric motor does not draw peak operating current all the time.)
I just wish I could find some specs on how much mechanical force would be needed to produce the electricity needed. Everything I can find on generators deals with units set up to provide household power or greater.
I envision an ICE powering a device to produce electricity for the motor and current to charge the batteries. Such a system might not provide enough power for the electric motor to run at peak load, but at times when the electric motor needed more power, perhaps it could pull from the batteries as well as the generated power.
Ideally, the generated power would be enough for the vehicle to cruise at 55-60 mph and still charge the batteries to some degree.
This is the reason CVT’s were supposed to be the future, except no one has managed to get the efficiency in them as they are all friction based linkages to produce the variability.
Peak power aside, the energy lost in transitioning mechanical power into electrical power and then back to mechanical power (none of those things has an efficiency even close to 100%) ends up negating any benefits to running the engine at a steady rpm (although that is a pretty big gain).
Check into KERS technology in F1 cars. The rules said “energy storage device” and they all seem to go with a mechanical flywheel system with a super-expensive CVT because they claim an electrical regenerative braking system would only yield something like 45% of the energy absorbed and put back to the tires, compared to 70% or something for the flywheel system.
Actually, no. It’s possible to get a 3000lb car to go 45MPH continuously with a 5HP gasoline motor.
http://www.evforum.net/forums/showthread.php?t=758
Check out the Mother Earth articles in that link, shows what a guy in Arkansas did with a 36V system and a small 1 cylinder ICE driving a generator. He has a lot of batteries in the car allowing for about 30 miles of range, and the generator is able to either top the batteries up or move the car. Said that the ORIGINAL design built in 1979 had problems only in mountainous terrain. He reported being able to see almost 90MPG out of this rig. Mother Earth later built an EV that got over 90MPG using the same plans with a few improvements, in the 1980s.
With today’s technology I can’t see not being able to do this and maintain a continuous 80MPH on the highway, and be able to accelerate like a scalded dog, and see 100+MPG. Imagine how much more efficient a fuel injected 2 cylinder motorcycle engine would be than a carbed 1 cylinder generator engine.
I know this might not be the most ideal way to move an EV vehicle around; I’m just trying to find a way to keep a vehicle going when batteries are getting low.
I spoke with a company that builds alternators, and the rep said he’s gotten a lot of calls on this idea. He offered the thought of multiple alternators charging batteries, and his company builds a variety of sizes (and can custom-build).
He estimates 5 hp of ICE power is needed per 100 amps of alternator output, and one of his stock alternator models makes 12 volts, 400 amps.
He had no information on charging times for EVs, though.
So if two 12-volt, 400 amp alternators are charging twelve 12-volt batteries (each alternator tied to 6 batteries), Would that be a 144-volt system being maintained at about 66 amps? That’s probably not enough to keep a motor going indefinitely, but perhaps it could boost range.
Maybe 3 of the alternators, each tied to 4 batteries, for a system being maintained at 100 amps? I’m envisioning the alternators and motor being housed in a small trailer that could be towed when longer trips are needed.
And a 40 HP air-cooled engine (dry weight 132 lbs. [59 kg]) to turn the alternators, assuming 5 HP per alternator needed:
http://www.kohlerengines.com/onlinecatalog/productdetail.jsp?engnID=180360
There is actually an alternator out there that could be used to provide full power. Unfortunately, they will only sell these to the military.
http://www.americanarmature.com/System%20Spec%20OBVP%20400.pdf
It produces 500 amps at 28V, or 14,000 watts of electricity with a turnon speed of 922RPM. You’d have to spin it up to about 3000RPM to get max power, most likely. Three of these would run the same electric motor used in the Tesla sports car.
I thought all was lost on this until I picked up a book on generators and motors, and found that a motor is actually a power converter. Assuming that wiring losses are ignored, if you wire two identical electric motors together and mechanically turn one at 1000RPM, the other motor with a load that matches the ICE will spin at 1000RPM. So, my theory is that instead of trying to find a generator head to provide the power, just get a larger motor to act as a generator. Being larger, it should be able to produce enough power when spun by an ICE to provide full power to the motor moving the car. It would then just be a matter of sizing the generating motor once you decide what motive motor you need.
Please, anyone pick this idea apart, so long as the argument of “using the ICE to turn the wheels directly is more efficient” isn’t used. I already know it isn’t, because this idea has already been built, with a fellow moving a 3000lb car at 45MPH from a dead stop with a 5HP ICE, while getting almost 90MPG doing it. As a direct drive a 5HP ICE couldn’t move a 3000lb car 5MPH, and might make 1MPG doing it. But I’d appreciate it if anyone who sees a technical problem with this working as it does putting in their nickel’s worth.
[QUOTE=Telco;4195]There is actually an alternator out there that could be used to provide full power. Unfortunately, they will only sell these to the military.
http://www.americanarmature.com/System%20Spec%20OBVP%20400.pdf
It produces 500 amps at 28V, or 14,000 watts of electricity with a turnon speed of 922RPM. You’d have to spin it up to about 3000RPM to get max power, most likely. Three of these would run the same electric motor used in the Tesla sports car.
I thought all was lost on this until I picked up a book on generators and motors, and found that a motor is actually a power converter. Assuming that wiring losses are ignored, if you wire two identical electric motors together and mechanically turn one at 1000RPM, the other motor with a load that matches the ICE will spin at 1000RPM. So, my theory is that instead of trying to find a generator head to provide the power, just get a larger motor to act as a generator. Being larger, it should be able to produce enough power when spun by an ICE to provide full power to the motor moving the car. It would then just be a matter of sizing the generating motor once you decide what motive motor you need.
Please, anyone pick this idea apart, so long as the argument of “using the ICE to turn the wheels directly is more efficient” isn’t used. I already know it isn’t, because this idea has already been built, with a fellow moving a 3000lb car at 45MPH from a dead stop with a 5HP ICE, while getting almost 90MPG doing it. As a direct drive a 5HP ICE couldn’t move a 3000lb car 5MPH, and might make 1MPG doing it. But I’d appreciate it if anyone who sees a technical problem with this working as it does putting in their nickel’s worth.[/QUOTE]
Did American Armature tell you that they would only sell to the Military?
You may not be aware of this but - Just because something is built to a Military Specification, does not mean it is not available to the public sector…
Using a motor as a generator and visa-versa; I can’t say a lot about this because I’m certainly not an electrical engineer - but I do know that they can function in this way for DC. Can’t say about AC at all. You can take any DC Generator and apply current to it and it will spin, although the phasing/positioning of the brushes seems to be less than optimal and the brush material on generators is generally carbon/graphite - while a true DC electric motor typically uses a material like Copper for the brushes. The Commutators are generally copper on both.
I have been comptemplating the use of an ICE as a range extender. My first thought was to use a generator to produce the power and just load the generator in the back of my truck (2001-S10) or connect a small trailer when needed. The drawbacks would be not having it all the time so I would have to plan my trips more and the efficiency problem ICE to generator assume 85% and generator to motor another 85% leaving about 72% of the ICE power to move the vehicle. I then tried to figure out how to use the ICE to power the vehicle directly and solve the problems that seem to come up:
[I]An ICE driven vehicle has a motor that must move the entire mass of the vehicle, at all speeds, including moving that mass from a dead stop. It must also be able to accelerate that mass from any speed to any speed. Running an ICE as a mechanical range extender though, requires that the ICE be optimized for multiple RPMs[/I]
This is true if you are going to use the ICE [U][B]OR[/B][/U] the EM but my idea is to only use the ICE to extend range. Around town I can use the vehicle as a plug in EV, when I go to visit my family, who live 100 miles away via state highways I would need some help.
My idea is to connect an ICE via an electric clutch and V-belt to the front of the EM, use the EM to get the vehicle up to cruise speed then start the ICE. An electronic cruise control will operate the ICE throttle to maintain speed, therefore you do not need a second gas pedal. If I come to a big hill and the ICE can not maintain I can push on the potentiometer and get the EM to help. The cruise control and clutch would be disengaged when the brake pedal was touched bringing the ICE back to idle.
I think this method would simplify things in that:
[ul]
[li]ICE can be geared to operate at maximum efficiency at cruise speed ie 55MPH
[/li][li]No clutch is needed since ICE will only operate in 1 gear (at cruise speed), no shifting
[/li][li]EM will operate vehicle at speeds below cruise speed (getting vehicle moving)
[/li][li]If there was a failure of the electrical system ICE could get me home using 1st or 2nd gear
[/li][li]A generator/alternator (able to put out say 20-30 amps @150V DC)could be connected to the ICE to charge the pack when parked[/ul]
[/li]
The ICE I am going to use is a 20HP 620cc Kawasaki, twin cylinder water cooled, which came in the Gator, the electric clutch came from a hydraulic pump (similar to AC clutch except stronger).
This method will not work for everyone and you will have to “drive” the vehicle (will not be automated) but I believe that the added 150 pounds for the ICE will make this a far more useful vehicle.
Bigfoot - Yes, they told me military only. It made me sad, because three of these alternators would have provided more power than I’d need.
Turbotom - Yes, that’s what I was getting at on why a much smaller ICE can be used to drive only a generator than would be needed with a mechanical drive. I’ll be VERY interested in your results since you’re quite a ways ahead of me on this. From the generator/motor tech manual I’ve been reading (a textbook picked up at the local engineering college bookstore) using a second motor the same size as the one driving the truck should produce more than enough electricity for the drive motor unless you drive long distances at max speed. Driving at a lower than max speed would allow the generator to run at max power production RPM, which would both drive the vehicle and recharge the batteries.
Anyone know how to figure the requirements and total effect when using multiple alternators for charging?
I spoke with a rep at a local battery store today. He indicated that, if alternators were used as a charging mechanism while the batteries were in use, then a 12-volt alternator would be needed for each 12-volt battery in order to keep power input and power drawn from conflicting. Does that sound correct?
The battery rep also said he would start his design of a charging system by looking at the output power of the charger provided in an EV kit.
The output of the two bigger chargers at the electroauto site are:
– 80-170 Volts DC, adjustable; and 17.5 Amps DC Max., adjustable
– “pack voltage” (not sure what they meant by that) of 96-240 volts DC and output current of 18-50 Amps DC
That’s the easiest way, and how it’s done on some of the high power audio installs. Check out these guys, they have information on multi-alternator systems and it looks like they have alternators that can be used for industrial welding. I’m just now checking them out. A welding alternator should be able to maintain a 100 percent duty cycle without puking.
Did more reading, they are saying 12 to 18 inch diameter on their 300+ amp 12V systems. Unsuitable.
And what would be the effect if a single alternator, say 12 volt, 400 amp, were tied into multiple batteries for charging?
I’m wondering if one alternator for every three batteries (with the alternator tied to each of the three batteries it’s charging) would work while the system is in use.
If you want to run a generator/alternator large enough to power the vehicle then I would go with one like this
http://cgi.ebay.com/20KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ150274834307QQihZ005QQcategoryZ106437QQtcZphotoQQcmdZViewItemQQ_trksidZp1742.m153.l1262
Car alternators are 3 phase AC that is rectified to produce DC so this unit at 20KW with the proper rectifier should put out enough to power the car and charge the batteries. You could probably get by with a smaller one probably 10 to 15 KW would be enough. It puts out 120 volts but could be overdriven to put out 140 to 150 volts easily. This would be much easier than trying to tie multiple alternators together.
this unit at 20KW with the proper rectifier should put out enough to power the car and charge the batteries. You could probably get by with a smaller one probably 10 to 15 KW would be enough.
Any idea on what the weight would be on that and the horsepower needed to drive it?
Here is another one that listed the specs
http://cgi.ebay.com/12KW-STC-3-Phase-12-Wire-generator-alternator_W0QQitemZ160261220839QQihZ006QQcategoryZ106437QQssPageNameZWDVWQQrdZ1QQcmdZViewItem
[U]Specififcations:[/U]
12kw Continous (12,000 watts )
4 Pole, 1800 RPM , 12 Wire
42 MM Shaft
4 Brush
Weight: 230 LBS
18 HP Diesel engine
24 HP Gasoline engine
Did some searching and came up with 2 options – there’s a lot of info here, so I’m going to put each option in quotes to make for easier comparison:
OPTION 1:
An engine option to turn the above-mentioned generatoralternator would be this: http://www.honda-engines.com/engines/gx670.htmIt’s a 24 HP gas engine (power curve shows 22 hp real-world maximum) with generators listed as an intended application. There’s a slightly smaller engine available that might put out right at 18 hp, but I picked this one so the engine wouldn’t be taxed to its maximum all the time.
Fuel consumption is .9 gallons per hour at 1/2 load, 1.39 gallons/hour at full load
– Dry weight of the engine is 95 pounds
– Oil capacity is 2 quarts
– 1 gallon of gasoline equals 5.8 to 6.5 lbs.
– Weight of the generator-alternator is 230 LBS
– I’m guessing 2 pounds (empty) for a 5-gallon gas can. Also perhaps could take the gas tank from the vehicle being converted.
– muffler not included – dunno what weight/cost on that would be …
– weight and cost of mounting hardware and an adapter to connect the motor to the generator-alternator also are unknowns.Call total weight of the set-up about 375 pounds (conservative estimate figuring in 5 gallons of gas)
Price for a new one looks to be about $1,300, so that plus around $520 for the generator comes to $1,820 – call it $2,100 after shipping, cost of a gas can and other peripherals.
That still leaves the need to tie the system into the EV’s motor and battery charging system.
OPTION 2: A unit already assembled:
– Price is $2,500 to $3,000
– Fuel tank and muffler are included, connection between engine and generator is already done, unit is stable and portable.
– Engine is same as above, but the option closer to $3,000 includes a unit that can run on LP Gas, Nat. Gas and Gasoline.
– A few options:
http://www.generatorquotes.com/order/H11000E5.asp?page=H11000E5
http://item.express.ebay.com/TRIPLE-FUEL-HONDA-POWERED-11K-WATT-PORTABLE-GENERATOR_W0QQitemZ300046937353QQihZ020QQcmdZExpressItem
14,000 Watt Gasoline Generator