Electric Cars

Hello Guest, please take this as a comment and not criticism.

I do not believe a flywheel directly coupled to the motors would be of any use, in fact in the case of an electric motor it would probably be detrimental. Internal combustion engines do not develop peak torque at idle RPM, thus they utilize a flywheel to store energy. Electric motors , depending on the type can develop peak torque when stalled.

I have heard that at one time some European street carts stored energy in a flywheel, connecting to an electrical source at each stop , and utilizing a motor to replenish the stored energy.

I'm not sure whether there would be a advantage to storing energy scavenged from breaking in a flywheel, but possibly there could be, just something to think about.

Individual electric motors could possibly have some advantages, and some disadvantages.

Internal combustion engines in order to reach peak efficiencies need to be heavily loaded. That is to say all else being equal a smaller engine will generally yield greater fuel efficiency, that is the nature of the beast.

Electric motor efficiency, (at least the AC motors that I normally utilize) does vary with load. I'm not sure to what extent the efficiency of the motor designed for this application would vary with load, so there could be some gains in controlling the motors load. However I tend to doubt that it would not be worth the effort, but just guessing here.

As far as using torsion springs I don't believe that would be a good idea. The weight, complexity, and frictional losses would have to be considered. I would think that either recharging the batteries, or storing breaking energy in a flywheel would be a better solution.

Regenerative braking is already employed in electric vehicles, to recharge the batteries. So I guess the only question here is whether there would be a advantage to adding a flywheel to the system

Adding weight to unsprung automobile components has a detrimental effect on handling that is proportional to speed. Wheel motors are good in high torque applications, but not so much on the freeway.

there is an electric motorbike in Japan that keeps it's battery charged by having the two wheels create a relative motion for a set of connected field coils as a conductor in a magnetic field. Basically its like an alternator that rotates off the direct rotation of the wheels instead of by a belt from the crankshaft of an internally combustible engine.

No there isn't. ffeJ

It's either Popular Science or Popular Mechanics for this month, but there's a new car designed similar to what you all are talking about.

Owning a hybrid, I can tell you weight, rolling resistance, wind resistance, and power transmission are that enemies of fuel efficiency. Cars with light weight batteries, diesel generation, with direct electric drive are the way to go. If you really want to see how to maximize fuel efficiency, look at GE's hybrid locomotive.

If you can make a locomotive even one tenth of a percent more efficient, you save thousands of gallons of fuel.

The Brits have put electric motor/wheels on a hybrid prototype, The one owned by BMW.

Flywheels are not a bad idea for storing energy. Especially with the new bearing materials and high tech balancing available today.

One negative issue with the application in automotive is collision. The nature of a flywheel is significant mass at high rpms. Where does all of this energy go when the flywheel stops in less than a second?

My answer to this question is "I don't want to find out."

You said: what would happen to the energy stored in the flywheel.

That would be a good question. Though I'm not sure it would be any more dangerous than unleashing hydrogen stored at 4000 psi. Every time I think about a hydrogen car, I get this strange vision of the Hindenburg.

Flywheels would be at least fun to think about, and I believe certainly more practical than the schemes of compressed air vehicles. Now the next question is how much gyroscopic effect would you get from the flywheel?

Hi YWROADRUNNER, The hydrogen burns hot so the heat goes up. Many survived the Hindenburg because the cab was under the heat.

One design I remember had a blowout panel on top of the trunk of the vehicle and stated it could handle failure. I don't remember if that was total failure at 4000 psi. But the concept was that the fuel took the heat up and away from the vehicle and passengers.

As for flywheels they have 2 problems: Gyroscopes move good in two axis only, and I've seen street racers flywheels come apart at 7,000 rpm? (best guess and before scattershields were common). Up through the firewall and down through the bed (pickup), the other half took a nice chunk out of the asphalt. Don't know how much energy was stored or even why the flywheel split in half but a storage device would need much higher rpms and weight. Failure containment would need to be heavy, costly or both.

I do think flywheels could be used for stationary power storage if the material and friction issues can be overcome.

Brad

A flywheel will require additional power to accelerate and to stop. If energy stored in the flywheel can all be used for regeneration, not too bad. But if there is an emergency condition, there will have to be an additional breaking system to convert that energy to heat. Don Garlits lost half a foot when an engine exploded, and the flywheel tore it off. That was the beginning of the rear engine dragsters.

When I was "daydream" designing a flywheel driven car, I considered a fluid filled, baffled, shell. In collision the shell would shatter and the energy would dissipate as moving liquid rather than flying chunks of steel.The shell would be fiber laden to stop it from breaking into pieces. Like a reinforced sac.

The gyroscopic effect would actually be built to assist traction and handling. Like some of the suspension level assist systems available now. No body roll with a giant gyro holding you straight!

THEN I WOKE UP!!! And went back to designing real suspension parts. HA!

How would the gyroscopic effect affect the ability to change direction?

Students from Princeton Community High School in Princeton, Indiana, USA tried to add weight to their tires for the "high mileage vehicle" entry. They mounted a bicycle tire assembly in a vise. Spun it by hand and timed the duration until it stopped. Then they filled it with water to full capacity. Hoping that would prevent sloshing inside the tire. Then they gave it a spin. The result was that the tire stopped much sooner than when it was filled with air only. They had hoped that it would work like a flywheel and coast longer.

They should have put their wheel in the freezer.......

The resulting frost and condensate on the tire would have caused it to spin out at the start of the race.

Even better. The initial low friction would allow the wheel to spin up to significant RPMs to make use of the suggested flywheel effect.

True, but then the heat would melt the ice and then we are back to sloshing around again.

Not if the competition was in Greenland.

electric motors do not require flywheels as there isn any torque variation or vibrations from the motor to be absorbed.that part can be taken care of with dampers in the wheels.as for power storage,one motor at each wheel + flywheels+lenkages reconnecting to battery recharge+synchronizing for all motors+differential settings and god knows what more.calculations are insane.to get it to be efficient would be a killer.

losses would abound such that power saved by individual motors would be cancelled at the least.failure calculations and protection from varios thrusts,stresses to keep efficiency going are also to be calculated.a single shaft axle system is still better i feel.wouldn a front wheel drive combat many losses??

systems to recharge battery using motion of wheels already exist.having said that i think its a great thought.im sure theres a way to make it work.

liklely to be heavier than singlemotor and expensive.

when one wheel is not being run either in front or rear it may cause driving imblanaces , particularly in turns.

If say one wheel is driving the entire car and others are not , then will this wheel operating at higher speed charge via other three wheels and also keep its flywheel run at same speed ?

your question is not very clear, at least to me, but,even though theres no need to have only one wheel powered,man invented the differential precisely to solve such problems.

I have been thinking along the same lines...and I'm with you on the flywheel design. It stores torque and would reduce the amount of power it takes for start-ups. However...I think the weight of a car affects how much energy is needed to power a car down the road the way we are accustomed to. I may be wrong, but I think if we designed a lighter car, our problems would be solved. If I'm not mistaken, it would take the same amount of energy to power a 1000 pound car (up to speed) with four motors as it would one motor. The only difference would be...is that you would have four wheel drive. And...that's not a bad thing. The problem is... trying to overcome the force of gravity, drag, and air resistence, and you're right...if we could recoup the energy wasted when we stop, slow down, set in traffic or at lights, or coast down hills, we could basically "squeeze butter out of a duck" with a flywheel. My idea was along the same lines but using two counter-rotating flywheels that run on a gimble. The weight and diameter of the flywheel would depend on the weight of the vehicle. The flywheel would be powered on the outer rim by a series of batteries like a huge electric motor. The shaft at the center would power a high output hydraulic pump which would power a hydraulic motor attached to a differential. When coming to a stop, the backflow would be reintroduced back into the counter rotating part of the flywheel spinning the flywheel back up to speed and charging the batteries. All four wheels would act like generators pushing power back into the batteries the more the brakes were applied. Depending on how much energy was used and if the batteries ran below a certain voltage, a solenoid would activate starting a small gas or diesel generator. If you made it home with the flywheels still turning...you could plug it into your house and reduce your electric bill.

Maybe with a few more ideas and a lot of engineering we could actually design a lightweight fuel efficient car we wouldn't have to feed like a hungry race horse.

Any idea's of why it wouldn't work? Thanks