Engine design question

[Aptera#965]

Ok my buddy just proposed this question to me while we were talking about hybrid designs.
I apologize in advance if this sounds like a really dumb concept (or asked already), so at the risk of embarrassment, I'll through it out there anyway :D

Why couldn't the drive system be setup in a way where you have the batteries supply power to the electric motor (which drives the rear wheel), but also have an additional pully attached to the electric motor which is connected to a generator which recharges the batteries? As the batteries use it's charge to turn the electric motor, the generator is recharging the batteries at the same time.

Wouldn't you be able to greatly increase range this way? Using a hi output generator with little to no drag on the motor?

It seems so simple to me, yet I'm sure that this has been thought of before and cannot be done for whatever reasons; can someone with a smarter brain please explain to me? Thanks!

[gistmarrs]

Or just put a huge wind turbine on the top of the car to recharge the batteries! :D just kidding!

[KarenRei]

TNSTAAFL (There's No Such Thing As A Free Lunch).

Generators impose drag on whatever tries to turn them, that drag *always* being greater than the amount of electricity they produce. You can only lose energy with this setup.

[fritzponds]

Ahhhh, perpetual motion!

[evolutionmovement]

The motor itself is a generator if you use mechanical energy to turn it, you generate electricity. That's the idea behind regenerative braking. Of course, it also works like a brake when used because of the drag imposed when generating the current.

You can't get something for nothing - damn thermodynamics!

[LQUAN]

I am sure many had one time or another try to spin the pulley on your car's generator by hand after the drive belt was removed. It does seems like it just spins freely on its bearings right? That's because at such low RPM there is almost no electricity generated. Typical automobile generator does not generate the required voltage (13.8V) to charge the battery under 1000-1100 RPM. Current generation increase as RPM increases because voltage is being regulated at 13.8 to 14.0V. The rotor harvest electricity from the electromagnetic fields (EMF) create by the permanent magnets on the stator. This EMF is a drag. The drag increase as RMP increase.

[futura]

In my sophomore year of high school; basic science class had a generator geared with a hand crank connected to a 75 W light bulb (Edison bulbs don't care if it's AC or DC). Each student would turn the crank and see how little effort it took...then flip the switch that closed the circuit to light the bulb. Jeez it took a lot of arm power to make that thing light! After that little experiment no one asked the teacher about perpetual motion with generator/motor combination. Although one member of the football team was finally able to burn out the bulb (I suspect he swapped in a 25 W bulb).

[Aptera#965]

Thanks for the education everyone :D

I didn't realize how hard itr would be to spin a generator, let alone at higher rpm's.

[n_dawg]

Regardless of how hard it is to spin, you'll never get more energy out of the generator than the energy you use to turn it. Thermodynamics is funny that way.

[gg222]

Just a few questions on what this gas motor for the hybrid will be like. I know it will be small (not a lot of room in the aptera).

Will it have an oil compartment? Will it use oil and air filters?
? Will it be like a lawn mower engine, a motorcycle engine, or more like a snow mobile engine? Is there any place on the internet where we might be able to see what these engines will be like?

[KarenRei]

Count on it being like a motorcycle engine, and definitely *not* like a lawnmower engine. Those things are dirty as heck.

[garygid]

Yes, ... gas tank, oil and probably an oil filter, exhaust and
catalytic converter, water and a cooling system, and radiator,
an air intake and air filter, and probably a fan.

Yes, it will most likely have all the good stuff that you know
and love. But, the type/brand/etc. is not known, so it is
not yet possible to say anything very specific about it.

Then, add the 12 kW generator that also acts as a starter.

[LQUAN]

Yes, ... gas tank, oil and probably an oil filter, exhaust and
catalytic converter, water and a cooling system, and radiator,
an air intake and air filter, and probably a fan.

Yes, it will most likely have all the good stuff that you know
and love. But, the type/brand/etc. is not known, so it is
not yet possible to say anything very specific about it.

Then, add the 12 kW generator that also acts as a starter.

That's the reason why I order the Type1e. Got to steer clear from ICE. I have been working on all of my all ICE cars since 15, I am sick of them. After cramping 2 semesters of automechanics into 1 while in high school, there is nothing in ICE cars that I cannot repair, including electrical and autobody repairs. I have rebuilt at least 3 ICEs. I have never taken any of my cars to repair shops for any problem since I learned how to drive, except for smog check and wheel aligments. I can maintain my dad's car long before I have my license. I am truly sick of working on cars. Ironically, my hobby, RC airplanes, all have ICEs. If I can find electric motors and batteries light enough to fly 25-30lbs RC aerobatic aircrafts without costing me an arm and a leg, I'll switch over.:D

[davidrools]

To be technical, it's an electric motor and a combustion engine. No electric engines or gas motors.

So for the hybrid's engine, I expect it to be most like a generator:
Honda 10kW standalone generator (http://www.hondapowerequipment.com/products/modeldetail.aspx?page=modeldetail&section=P2GG&modelname=EB11000&modelid=EB11000K1A)
Single speed (always running full throttle, the most efficient place to be), probably air cooled to save weight/complexity/maintenance/increased reliability. Uses a conventional oil filter.

Keep in mind that 12kW is only 16hp. Of course the generator would have to make a bit more to make up for efficiency drop of the generator but is still easily attainable in a two cylinder engine. Maybe around 500cc. It wouldn't need to be throttled because any throttling would reduce efficiency, and the engine speed can be controlled by the load placed on the engine by the generator/charging controller.

[LQUAN]

Just wondering, does the Type1h required smog check every 2 years like ICE vehicles?

If yes, then how do you get the ICE generator to run while the vehicle is in "P" position to do smog test?

For ICE generatr to run clean to pass the test, it has to run continuously for at least 1/2 hour prior. I wonder if there is an override mode where you can activate/deactivate the generator manually.

[n_dawg]

Prius can't pass Georgia emissions test - Autoblog (http://www.autoblog.com/2007/04/16/prius-cant-pass-georgia-emissions-test/)

Hopefully they've wised up since then.

[3-4-me]

I'd be BS if you had to smog it, I mean I don't need to smog the 5KW Onan on my motorhome.

[gistmarrs]

My guess is that they won't require smog since the genny isn't actually powering the wheels, it is charging the batteries.

[Apt Performer]

I actually asked this question in another forum which was slightly off topic there (better here - but topics do sometimes get naturally bent as discussions bloom).

I was stating that one of the reasons I wanted the hybrid over the battery only was the additional safety of having a gas engine kick in should the battery system fail. Then it was pointed out to me that the gas engine ONLY supplies power to the batteries and isn't connected to the drive train... which prompted this question from me:

Seems to me that (and this is more observation than judgment) if the gas engine only drives the battery and not the car, shouldn't they refer to it as a gasoline-driven generator rather than an engine? Don't other hybrids with gas-assisted engines like the Prius also drive the engine as opposed to just recharging the battery?

Please forgive my obvious lack of knowledge in this area.

[garygid]

The Prius and Insight are examples of different configurations of
the "Parallel Hybrids", where the electric motor, or the gasoline
engine, or both can turn the drive shaft, which can turn the wheels.

The Aptera is a "Series Hybrid", where only the electric motor
turns the wheels, and the gasoline engine is used to produce
electricity (when needed) by turning a generator. Typically,
the electrical output of the generator can be used to power
the electric motor, as well as charge the batteries.