Kenetic Energy Recovery Systems

[Ratliff]

Suppose if a few hundred pounds of ballast added to a car were instead of inert dead weight a flywheel? Suppose before leaving the starting line the driver stored energy in the flywheel by using the engine to spin it up to 8,000 or 10,000 rpm. It wouldn't change the cubic inches, or the induction method, or the type of fuel. The current rules say nothing about it.

[sanger351]

I am new to LSR but not mechanical things.  A flywheel is a very good tool to smooth out loads and power pulses with all of its inertia.  I believe that the required additional drive devices, both power up and power to the wheels, not to mention the emergency braking system would make this concept unfessiable in an accelerating car.  It would need some sort of CVT trans that would allow higher car speeds as flywheel rpm decreases and would have to apply the power without blowing the tires off the track. Without a power source it would quickly become a drag on the system.  Lastly can one imagin the saftey concerns of a flywheel failiure of a flywheel large enough to do what is suggested.  Assuming the sharpnel is contained the car would be tossed about like a rag doll.

Now I have thought about using this idea for an ultimate mileage car contest held locally.  The flywheel could help accelerate the car from a stop and then maintain the desired speed from deviations in the track, wind, etc. thus improving mileage.

[Ratliff]

Kenetic energy recovery systems are being added to F1 cars next year. However, as usual in Formula One, a standardized system is being used that's so pasteurized and homogenized it's not going to be the power boosting "passing gear" many people first envisioned.

One alternative method for LSR would be a small onboard air compressor that charges a storage tank. Gearing a compressed air motor to the drivetrain might be easier than coupling a large flywheel.

[sanger351]

Or someone could have the engine wind a huge clockspring and unleash it at speed.  Maybe Swatch or Rolex could  sponsor the car.  The downside is that the car would be required to have a large wind up tab on its decklid or roof reducing the areodynamics of the car.



The F1 kenetic energy recovery unit is intended for use on sharp road courses with lots of slowing and accelerating.  Hopefully with the benifit of increased brake life and quicker acceleration off the corner.  The unit would have no benifit on a highspeed oval or susstained straight line acceleration.  However I bet the main benifit is to ease the pressure of treehuggers on F1 racing.  Some experimental medium duty delivery trucks use a hydrostatic regenerative type braking/accelerating system to increase fuel mileage and reduce noise in city enviroments which IMO is a contructive good use of the technology.

[Seldom Seen Slim]

Not to rain on anyone's parade, but I think we've already discussed flywheels and such things for LSR - and we came up with the feeling that anything of the ilk would be considered another power source -- just like adding a second engine -- and therefore not allowed.  Compressed air turning a wheel, flywheel, clockwork -- whatever, it's a second source of power.  Someone care to check the archives for this?  One - two - three  NOT ME!

[Ratliff]

Since there are aleady classes for electric cars, it seems to me the most sensible approach under the existing rules structure would be to use energy recovery systems as a supplement to or replacement for batteries. For example, an electric car could use an air compressor while braking then during the next run use the energy recovered as compressed air to drive a generator. Since electric cars don't have the horsepower of piston engine cars, this could also be where an energy recovery system would be of most benefit.

[RichFox]

Braking has not been a big part of my Bonneville experiance

[sockjohn]

Since there are aleady classes for electric cars, it seems to me the most sensible approach under the existing rules structure would be to use energy recovery systems as a supplement to or replacement for batteries. For example, an electric car could use an air compressor while braking then during the next run use the energy recovered as compressed air to drive a generator. Since electric cars don't have the horsepower of piston engine cars, this could also be where an energy recovery system would be of most benefit.

The energy density of Li Ion batteries is better than compressed air storage energy density's, especially when you factor in the motor/generator needed.

I bet somebody would throw down their $100 pretty quick, even if a high rpm flywheel or high psi air storage made it through tech.  That and a rule change request would be submitted pretty quick.

[Ratliff]

Since there are aleady classes for electric cars, it seems to me the most sensible approach under the existing rules structure would be to use energy recovery systems as a supplement to or replacement for batteries. For example, an electric car could use an air compressor while braking then during the next run use the energy recovered as compressed air to drive a generator. Since electric cars don't have the horsepower of piston engine cars, this could also be where an energy recovery system would be of most benefit.

The energy density of Li Ion batteries is better than compressed air storage energy density's, especially when you factor in the motor/generator needed.

I bet somebody would throw down their $100 pretty quick, even if a high rpm flywheel or high psi air storage made it through tech.  That and a rule change request would be submitted pretty quick.

Batteries are energy storage devices, not energy generation devices. As long as stored energy is converted into electricity that turns an electric motor, it's hard to see any fundamental difference between batteries, ultracapacitors, flywheels, compressed air, or some other method of storing energy.

One question in land speed with batteries versus compressed air for energy recovery during deceleration is, which method can recover the most energy in the time available?

Given that fuel cells generate electricity rather than store it, how are the Buckeye Bullet II streamliner and Ford Fusion classed versus battery electrics?

[tortoise]

Given that fuel cells generate electricity rather than store it, how are the Buckeye Bullet II streamliner and Ford Fusion classed versus battery electrics?

Batteries do not store electricity. They convert chemical energy into electricity, same as fuel cells.

[Ratliff]

Given that fuel cells generate electricity rather than store it, how are the Buckeye Bullet II streamliner and Ford Fusion classed versus battery electrics?

Batteries do not store electricity. They convert chemical energy into electricity, same as fuel cells.

Fuel cells are not capable of storing a charge. They are a device that consumes chemicals to generate electricity.

Batteries are not capable of generating electricity. They require an external system to generate the stored charge.

[tortoise]

Fuel cells are not capable of storing a charge. Batteries are not capable of generating electricity. They require an external system to generate the stored charge.

I said, Frankie, that batteries, like, fuel cells, do not store electricity. The fuel cell, in conjunction with the externally stored fuel, makes electricity. A battery's chemical energy is stored within the battery, but the chemical energy in a battery is not necessarily generated by charging the battery electrically. Did you ever make a potato battery? Did you have to put it on a charger first?

[Ratliff]

Fuel cells are not capable of storing a charge. Batteries are not capable of generating electricity. They require an external system to generate the stored charge.

I said, Frankie, that batteries, like, fuel cells, do not store electricity. The fuel cell, in conjunction with the externally stored fuel, makes electricity. A battery's chemical energy is stored within the battery, but the chemical energy in a battery is not necessarily generated by charging the battery electrically. Did you ever make a potato battery? Did you have to put it on a charger first?

A fuel cell vehicle has an exhaust pipe. Battery vehicles don't. A battery can go from a full charge to dead with no loss of the chemicals inside. Anytime a fuel cell vehicle is generating electricity it's getting lighter because vapors are going out the exhaust pipe.

[tortoise]

Speaking of kinetic energy recovery systems, I seem to remember reading about a much simpler method of same on this site, at El Mirage, I think, involving the push car pushing the race vehicle to a speed much greater than the race vehicle was capable of, and using the race vehicle's motor to merely retard the rate of deceleration. As I recall, the "nothing in the rulebook against it" argument didn't fly.

[tortoise]

A fuel cell vehicle has an exhaust pipe. Battery vehicles don't. A battery can go from a full charge to dead with no loss of the chemicals inside. Anytime a fuel cell vehicle is generating electricity it's getting lighter because vapors are going out the exhaust pipe.

How does any of this bear on my simple statement that batteries do not store electricity?

Electrically powered vehicles, whether the electicity is supplied by fuel cell or battery, are still electrically powered. If you wanted a sort of "vintage" class, I guess you could restrict it to lead-acid batteries, but this seems premature, given the state of LSR electric vehicle competition.