Is anyone building a controller that would interface to a range extender internal combustion engine? I think there are some great batteries in the works (EEStor, nano wire lithium ion, ect) but they are still 1 to 3 years out. I would like to do a conversion now with limited battery capacity (to save money on the cost of the batteries) but still get better than the average 19 MPG my '99 Acura TL gets now. Even getting that to 35 or 39 MPG (with maybe a 20 mile electric only range) would be great!
But then, when ultra capacitors and 10x lithium ion batteries get here be able to drop them into the car and get 250 to 300 mile electric only ranges.
Anyone out there thinking along these lines too?
Jeff, we are thinking alike.
My plan was to get a dual shaft EV motor. The extra shaft would be driven by a 9-10 hp ICE. I plan on using a simple Horsonal shaft air cooled single cylinder engine. These are light and inexpensive. Life is about 1000 hours or about 50,000 miles.
The ICE would be coupled to the electric motor with a belt driven torque converter. This set up would allow the engine and motor to turn at different rpms. This will also allow the ICE to idle with out spinning the EV Motor, since the converter doesn’t lock up until the ICE spins about 1300 rpm .
The other advantage to the Torque converter is a torque multiplier and allows the small ICE to develop more torque at low EV Motor shaft speeds.
I want to control the ICE throttle with a control servo. Ideally, i would like to keep the motor at 80% load, since this is will allow the most range extension without harming the ICE and alos is the most efficient load for the ICE. What i plan on doing is figuring the top speed that the ICE alone running at 80% load will get the car up to. Then I will simply have a servo to pull that throttle open to the 80% load at that speed. Then in actual practice, the EV Motor will provide all the power needed to go faster than the speed attainable with the gas motor alone. It will also assist in acceleration at lower speeds.
The car I want to use is a vw squareback. it is geared stock so that 3rd gear would be good for electric only and short trips. Fourth gear would be for combined power. The torque converter on the IC and high torque of the electric motor combined should allow a starting from a dead stop to highway speeds without shifting out of fourth.
Even though this is a manual tranny car, it would be driven as an auto. The driver places the tranny in third for electric only and in fourth for ICE assisted.
My rough math and from what I have learned so far, with 8 100ah lead acid batteries and a 96 volt motor, i should have a range of about 40 miles on batteries alone and a speed of about 65 mph.
With gas assist, range should increase to about 100 miles ( highway) and speed I will limit to 75 mph. Should get about 70-80 mpg. This is very rough math and by no means I’m an expert.
Wow, you put a lot of thought in to it. I fear I may not be able to fabricate so many special parts though.
I was thinking of a setup similar to the Volt, where the ICE has no direct connection to the wheels (for simplicity).
My '99 TL is rated at 225 HP, and she will get up and go when you put your foot in it. But at this point I am more concerned with MPG so I can afford to drive it …then when the new batteries get here being able to go all electric, I pay 15.3 cents per kwh. Not the cheapest in the country but still being able to drive for about 3 cents a mile would be awesome!
I did find this:
…although I’d prefer the ICE not be on a trailer behind the car.
It’s too bad I just had to rebuild the transmission in my TL (in January), that $3500 could have gone towards the conversion. Oh well…I did need a car to drive.
My thought was if there was a controller out there that supported an ICE as an electric source (and could start the ICE and turn it off as needed) that might be the way to go now. To have a set up similar to a diesel locomotive (but with a small set of batteries for short travel and regen braking). Then, as I said, when the good batteries get here drop them in for much longer electric only driving.
But it appears no one makes a controller like this yet…
Actually having the ICE direct drive the Electric motor is more efficient and cheaper. all the parts are off the shelf and might add $1000 to the projeect.
If you have a IC drive a generator then convert that to dc to charge batteries, alot is lost is the conversion steps.
What you are talking about could be as simple as straping a small gas generator in the trunk.
But again, you losing a lot. to me it defeats the purpose of economy. With a direct drive IC assisting the electric, no extra generators and converters are needed. This means it will be cheaper and lighter.
If you really want a controller that can monitor you battery-pack and start and stop an ICE on demand, then find a totaled Toyota Prius and salvage the computer.
Then look in google for “Prius hacks” the Prius computer can be easily modified to start and stop an ICE by adding a momentary switch or totally reprogrammed with any charging algorithm you desire.
The advantage to a range extender being mounted in a trailer is you don’t carry the weight when it isn’t needed. If you need the range for your daily driving then you need a true hybrid or an EV with more range. If you want to build your own hybrid then you are very ambitious.
Probably a little larger than needed, but it’s in the Super Quiet line, and has electric starter.
Runtime = 7 hours at max load, (23.3 Amps @ 120V)
So roughly…Highway miles @60MPH x 7 hours = 420 Miles on 3.74 gallons of gas (112MPG?!?) … not including any charge you might have had from being plugged in.
having the ICE drive the wheels is much better, having an ICE drive a gen, you have a loss of power every step of the way.
Plus say you have 8hp gas engine driving a gen set and 30 hp electric motor driving the wheels, you only have 30 hp total to drive the wheels.
When the ICE is coupled to the electric motor, you have the total Hp of both engines to drive the wheels 8 + 30 =38 hp. So the car will be faster.
Say your electric motor has regen. then you could park the car in neutral and have the ICE drive the electric to charge the batteries, say while you are shopping or at work, if no plug was available.
It’s very possible to do what you want, in the solar power world the better controllers have a circuit to cut in a backup electric start generator when the batteries are depleted and not enough solar is coming in, so as to not allow the house to run out of power or go low enough in charge to damage the batteries. No idea if a solar controller would be suitable for a motor vehicle, but it can’t be hard for a mechanical engineer to build a circuit that will trip a relay when voltage falls below a certain threshold then connect that circuit trace to the generator’s starter circuitry. In fact, you might even be able to find a generator that has a voltage sensing autostart capability.
I’m still toying with the idea of what you are doing, only taking it a step further; using a genset as the prime power producer, with only enough battery capacity to act as a load bank, say 50-100AH at the required voltage. Was thinking a bunch of 12V motorcycle batteries in series. The problem I’ve run into with this thinking though, is finding a genset both strong enough to run the motor, yet small enough to fit in a vehicle.
I’d found a military generator that would be plenty strong enough if 4 were mounted to a small, efficient ICE and fit in my existing engine bay, but they won’t sell them to civilians. The one I found is capable of generating 14,000 watts at 28V at approximately 2000RPM, and fits under the hood of a HMMVW. Having been an HMMVW mechanic in a previous green-suit wearing life, I can tell you that there’s not much room under the hood, and the generator they had looked about the size of a GM CS-144 alternator, perhaps a bit larger. Would have been perfect.
At this time, I see no way for my idea to work, but yours is very doable.
How does that save gas, using a gas motor to generate electric power?
My thinking is that it would take less petrofuel to provide electrical power for an electric motor to move a car than it does for an ICE to do so. The inspiration is the diesel electric locomotive, which burns 3 gallons per mile to move a loaded train. Figured it out one day, the locomotive pulling a load at 3 gallons per mile would be the equivalent of some 450 semis that would have to get around 60MPG each to move the same weight the same distance.
The savings would come from the fact that an ICE in a car has to be able to operate efficiently across a wide RPM band to operate a car, but a generator runs best at one RPM. An ICE optimized to run at that one RPM can be a lot smaller and far more efficient than the ICE designed to operate under any conditions across that wide RPM band. For example, I once had a Camaro that I had to do a lot of long distance driving in. Found that if I maintained a set speed I could see 30MPG out of the car, but if I either dropped or increased speed mileage would drop. I’ve also seen similar mileage responses from other vehicles, with the best MPG speed varying depending on engine size and vehicle type.
By running the vehicle strictly off the generator, the need for moving around a ton or more of batteries is also eliminated, meaning you can run an even smaller electric motor, which would need an even smaller generator. Or you can still size the motor as though you had to move the batteries, size the generator a little larger, and have a much faster vehicle, making it much more usable. This also eliminates the need to have two vehicles, since you’d not need one for around town and one for long distance driving. Range is what is keeping the EV from being a major hit right now, and if an ICE generator powered EV can be made to work well and save fuel, it would help matters all the way around by extending our petrol resources, cutting pollution, and bridging the ICEV to the EV.
What you are talking about is a hybrid. You’ll need 2 things to achieve your goals - a small battery pack as you’ll need the extra power for acceleration, and you’ll need a fairly aerodynamic car. My Jeep Rubicon needs about 39.6 hp for steady state at 65 mph. I thought about making it a hybrid, but a 45 hp generator would not fit under the hood, much less not exceed the GVW.
Here’s an idea - Cars in the 1920 - 1930’s typically had a wooden trunk mounted aft of the rear bumper. If you put a hitch on the rear of your EV, you could put one of the hitch buddy’s in it - that 2’ x 4’ platform. Strap to it a generator for extended trips ! Easily remove it for short trips ! Northern Tool has a 5kw diesel for $1400. It burns 4 gals in 9.5 hours at 2.5K… so in continuous use, you’re looking at only 37.5 mpg or so if you started with a charged pack of 11Kwh (many guys get about 50 miles for a 22Kwh pack, so this would supply the energy of a 25K pack over 4.5 hr.) But this is not very efficient (air cooled) and loud.
If you wanted a much better solution, liquid cooled more efficient, you’d have to make your own. - $4700 for a 26 hp diesel from B & S, and a generator head of 15.5kw for $1089
This would be quieter and last longer…
Maybe a new company could be formed to produce an EV with a small battery pack of about 10Kwh - enough for about 20 - 25 miles… and a sister company could sell the Gen set to go with it and mount “temporarily” on a hitch. This would side step EPA and offer a lower price EV that can make long trips.
Actually, no. A hybrid uses two different motors to provide power to the wheels. The setup of which I speak has no direct connection between the motor and the wheels. A hybrid has the same efficiency problem as an ICE, the ICE has to be efficient across a wide powerband and has to be able to move the vehicle across a wide powerband. This requires a smaller engine than a straight ICE setup does, but a larger engine than a genset would. The system I envision would have no connection between the ICE and the wheels other than a current carrying wire.
[QUOTE=Telco;3503]My thinking is that it would take less petrofuel to provide electrical power for an electric motor to move a car than it does for an ICE to do so. The inspiration is the diesel electric locomotive, which burns 3 gallons per mile to move a loaded train. Figured it out one day, the locomotive pulling a load at 3 gallons per mile would be the equivalent of some 450 semis that would have to get around 60MPG each to move the same weight the same distance. [/QUOTE]
The efficiency of a train for moving large loads over long distances comes in large part from the low drag of having steel wheels running on steel rails. With no stop signs or traffic lights, a train moves steadily from origin to destination.
Engines and generators are not very efficient. For a train, a diesel/electric provides a good way to accelerate a large load using multiple engines without dealing with constantly shifting multiple transmissions. An ICE/electric drive in a car would not be as efficient as an ICE with a manual transmission.
Sorry to rain on your idea.
[QUOTE=Telco;3555]Actually, no. A hybrid uses two different motors to provide power to the wheels. The setup of which I speak has no direct connection between the motor and the wheels. A hybrid has the same efficiency problem as an ICE, the ICE has to be efficient across a wide powerband and has to be able to move the vehicle across a wide powerband. This requires a smaller engine than a straight ICE setup does, but a larger engine than a genset would. The system I envision would have no connection between the ICE and the wheels other than a current carrying wire.[/QUOTE]
Yes, that’s called a hybrid. Really. There are parallel hybrids like you are referring to with both motors attached to the wheels, then there are series hybrids with the ICE powering an electric system that is attached to the wheels.
And you’re entirely correct in the part about the sweeping rpms = porr efficiency, this is why CVT’s are such a big deal. The problem is that at cruising speeds (nearly constant rpm anyway) the losses between the ICE-generator-battery-electric motor ends up sucking efficiency. It is most efficient to have the ICE drive the wheels on the highway and go back to what you’re talking about for round-town stuff, like the Prius’s system of variable balance between the electric and IC power sources.