Help converting 220 AC to 220 DC @40 amps

[Oznog]

Well, people have argued the "range exender" generator. You can argue whether the emissions and expense justify this because you'd be able to use the EV far more often.

The facts remain that it can't make wheel power from gas, biodiesel, or any combustible fuel much better than ICE and probably worse. Its emissions will be frightening by modern car standards, it's gonna be huge, loud, and smelly unless you find something real special in generators. Get a realistic figure of how many KW it takes to make the vehicle cruise at a particular speed (it's quite a lot!). These problems are hard to get around because the bottom line is it's not likely to have mpg gains over putting the same gas or diesel in the original engine.

You can tap its exhaust into the car's original exhaust system to use the muffler but these gennies radiate a lot of noise off the engine itself. Contrary to the "superhummer guy", vegetable oil biodiesel does not come with any inherent difference in the noise level.

A few guys actually sawed a front wheel drive car in half, welded on a tow bar, ran a throttle cable out of it, and actually used it as a gas/diesel "pusher trailer" to transport the EV over long distances. Personally, holy crap, I can see the dynamics of that are so wrong- in a turn, its pushing force is trying to make the vehicle's rear wheels skid sideways and jackknife you. Not something you wanna deal with in rainy weather. So far haven't heard of any accidents but it's only been done a few times.

 

[audioguru]

What happens when you drive a fully loaded Prius up a mountain then the battery runs out? Is its tiny engine powerful enough to push the car up in 1st gear? Then won't it also run out of gas after a few days and only halfway up?

 

[Oznog]

Yeah, the Prius engine will get it up there once the batt's done, just slowly.
Generators on the size you're used to seeing at Harbor Freight Tools and all aren't anywhere near big enough to even keep it going down the road, well maybe at 15 or 20 mph but nothing realistic.

Keep in mind that the Prius' remarkable mpg isn't even a direct result of being a "hybrid". The thing is it uses an "Atkinson Cycle" 4-stroke, never before seen in a car engine. Atkinsons' is much more efficient but has a poor peak power output for its size and would not be considered driveable in a normal car. The battery booster makes it driveable by lending an impressive peak power. Just as important, the Prius has one of the lowest coefficients of drag ever seen in a car, experimental or otherwise. It's quite light. The drive train and stock tires makes a low rolling resistance. Half the drag of a big, boxy car already gets you twice the highway mpg right off the top without doing any hybrid/engine tricks.

 

[Helder Ferreira]

Prius has about the same power as a normal ICE. The difference, since it has 2 electric motor/generators, if it runs out of battery wich is impossible (the computer NEVER let the battery go below 40% of the charge). The system finds the correct combination of RPM ( usually at the peak RPM/Torque curve) of the ICE. At this speed the MG1 generates enough power to feed the MG2 to control the speed of the car. In a normal car, since you have a fixed ratio between the ICE rpm and the vehicle speed, you have to go in low gear all the time. Since the Prius has a CVT it will pick up or loose speed depending on the load condition. The engine will turn at a constant "high revs". Another fact about the battery. The computer never charges the battery abouve the 80% limit. This way the battery should last at least the 8 years of the warenty.

 

[mneary]

So the CVT can always keeps the ICE at maximum power or efficiency? Clever.

I've had more than a few ICE cars where, in 4th gear up a mountain I would accelerate nicely. But I would be approaching maximum safe RPM. Then I would shift to 5th and slow down due to lack of torque. I guess the CVT could give me 4.375th gear or whatever is necessary.

 

[Helder Ferreira]

CVT stands for continuous variable transmission. You can find a simulator here: **broken link removed**

 

[Oznog]

So the CVT can always keeps the ICE at maximum power or efficiency? Clever.

I've had more than a few ICE cars where, in 4th gear up a mountain I would accelerate nicely. But I would be approaching maximum safe RPM. Then I would shift to 5th and slow down due to lack of torque. I guess the CVT could give me 4.375th gear or whatever is necessary.

Well this is particularly important for the Prius' Atkinson-cycle engine:
**broken link removed**

A significant loss in traditional engines is the fact that on the intake, if the throttle's not 100% open it reduces the amount of air being taken in by creating a partial vacuum in the cylinder on the intake stroke. That wastes power to draw the piston back against the vac it creates. Atkinson cycle instead just changes the length of the intake/compression stroke so it only takes in the air it actually needs thus no vacuum. But this is difficult to throttle (actually Atkinson shouldn't have a "throttle" at all) and I believe it generally has a funky power band too. The CVT makes it usable by allowing it to sit at one RPM and the batt makes up for its lack of peak power.