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-   -   How The Easiest Hybrid Diy Could Be Done... (http://www.fuelly.com/forums/f35/how-the-easiest-hybrid-diy-could-be-done-7397.html)

trautotuning 01-25-2008 08:09 AM

How The Easiest Hybrid Diy Could Be Done...
I SAY (not an expert :) )

Simply put a 10hp (ala insight) engine connected to a fifth wheel, an on and off switch, and directly hooked up to the battery.

How would it work?
Go 60-65mph, turn electric engine on, stop pressing the gas pedal as much (close to idle, but just enough to slightly adjust the speed) and vuala! The alternator supplies the energy needed for the engine to run...

That way, instead of going 2500+rpms you would be going 1000-1200rpms and saving gas.


Or am I thinking WAY to simple here? I KNOW SOMEONE has had to try this, did it work or did it not and why?

kamesama980 01-25-2008 08:15 AM

you need X horsepower to maintain speed. you can either drive the wheels with the engine at that HP or you can convert rotational force into electrical and back into electrical. and lose some to inefficiency in the process...especially at 12v.

problem 2: most hybrids run off 240-350v 3-phase AC power...not what's coming out of the alternator. 12vDC motors are much less efficient. a 10hp 3-phase electric motor is pretty big (150-200lbs) and most hybrids integrate it into the drivetrain in a non-transferrable way.

BTW an electric motor is not an engine. I assume you mean use the insight electric motor.

trautotuning 01-25-2008 08:23 AM


Or even simpler, get a 10hp diesel engine (on eBay for about $400) and connect that to a wheel. You could even use it in stop and go traffic and even completley turn off the big engine in your car... ? Easier and cheaper than electric.

GasSavers_Ryland 01-25-2008 08:28 AM

If you could find a 12 volt electric motor large enough to work, it would work... for about 10 minutes if you are lucky, at that pont your battery will be dead, your wires will be melted, and such a large load will be put on your alternator that if you don't blow the fuse, it will simply lock it up, and start burning up the belt that drives it.

GasSavers_Red 01-25-2008 08:55 AM

Not exactly the same method of execution but Mike D. did more or less the same thing with his Insight


thecheese429 01-25-2008 09:53 AM

I would just put an engine in there with a throttle control in the cab/front of car. a gas/diesel engine in the trunk so you could just shut the engine off completely when you got up to cruising speed. you could just pop the clutch when you needed a little more oomph from the big engine. you would also have to make some way of routing the exhaust out of the car. then a bar with a wheel and a belt going to the wheel and the bar would be mounted on a pivot with a spring for flexibility. this is, after you have cut a big-ish hole in the floor of your trunk/truck bed. you could seal it with a nylon brush on either side. there would have to be a pretty big pulley on the engine, to make the wheel go fast enough for 50-60 mph.

I agree this is a good idea and it's even better if you can make a boom that goes out behind the car so you don't have to cut a hole. maybe it goes over the lift gate (in a truck) then there are two pulleys attached to each other and two separate belts.

what do you think guys?

trautotuning 01-25-2008 11:45 AM

^^^ Exactly...

The problem is the gear reduction, if the shaft is (lets say) about 1/4" and spins at a max of 3,500rpm's what size of reduction gears would you need to get it right at 60mph? (to use it in the highway).

Or you could probably also mate it to a small motorcycle transmission or something simillar so you could use it at low and high speeds?

If you did this to a Civic VX or similar, I bet you could easily net around 80mpg in highway... ?

Project84 01-25-2008 12:53 PM

Dangerous much?

Engineering nightmare much?

Optimistic much?

I really don't think its safe practice to be placing ANYTHING inside the driver compartment that is rotating at 3,500 RPM... or even 10 rpm.

for the sake of contribution...

why not take a motor (you choose AC or DC) supply w/ the proper power, and customize your drive wheel/wheels (2 motors for CV) by mounting up some type of gear inside of the wheel, maybe like a round track w/ teeth, then use a switch to turn the motor on/off to help rotate those wheels forward. If it took 20% load off the engine, it would help somewhat. I have enough spare motors at work I bet I could make this happen... although I'm doubtful because most of the motors I have are the correct size, and yet, only 1/2 or 1/3 HP. I do however, have a 7 HP spare motor for my air compressor, and its practical to mount a gear on the end of the shaft and then do the above to the drive wheels... supply power and a switch.... it would work... much easier this way I think.

Keep in mind, I haven't thought that out at all.

On second hand, I bet you could make a really fun go-kart using the method above.

thecheese429 01-26-2008 03:49 AM

you wouldn't have to have anything spinning in the drivers compartment if you had it all in the trunk. quieter too.

yes of course it would be quieter to use electric, but then you wouldn't be getting the most possible mpg, because you convert the torque into electricity then back to torque. at 12 or even 24 volts it ain't too efficient.

GasSavers_Erik 01-27-2008 03:21 AM

If an 8 inch trailer tire was used as a spring loaded "5th wheel", it would need to turn 1200 rpm to give 60 mph. This would be a simple 3:1 engine to tire reduction. So, weld an 8 inch pulley to the trailer tire rim and use a 2.5 inch pulley on the motor (assuming 3600 rpm).

My math: tire diameter= about 16 inches. Circumference= about 50 inches. Inches per mile= 63,360 / 50 inches per revolution = 1267 revs per minute for 60 mph (1 mile per minute)

Hmm, so you say they use a 10 hp 3 phase motor- I have two 7.5 hp 3 phase motors (240-480 volts) laying around. So assume the hardest part is making the box that transforms 12 V DC into 3 phase AC. And then there is the issue of hauling around 10 or so car batteries.

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