MYT engine

[jake]

Automan is right.

Simple calculations can demonstrate that you aren't going to get 200 mpg by changing a carburetor - no matter how completely you burn the gas.

There is a finite amount of energy in a gallon of gas, and that energy will only push a car so far at a given speed.  Hundreds of miles is out of the question at any reasonable speed, even if you capture 100% of the available energy and convert it to movement.

Making a few reasonable assumptions you can show that the energy in a gallon of gas might push an average sized car 100 to 150 miles - at 60 mph - if the engine was 100% efficient  With thermal and friction losses approaching 70% or more in the engine, it is unreasonable to think you will achieve anything near 100 mpg.

The exact theoretical mileage would depend upon the drag coefficient and the frontal area - neglecting rolling friction and other non-aerodynamic losses.

By far the easiest way to extend mileage is to slow down.  The mileage decreases with the cube of velocity.  It takes 4 times the force and 8 times the power to double the speed of a vehicle.  The difference between 55mph and 70mph is very significant.

[Liberty]

Automan is right.

Simple calculations can demonstrate that you aren't going to get 200 mpg by changing a carburetor - no matter how completely you burn the gas.

There is a finite amount of energy in a gallon of gas, and that energy will only push a car so far at a given speed.  Hundreds of miles is out of the question at any reasonable speed, even if you capture 100% of the available energy and convert it to movement.

Making a few reasonable assumptions you can show that the energy in a gallon of gas might push an average sized car 100 to 150 miles - at 60 mph - if the engine was 100% efficient  With thermal and friction losses approaching 70% or more in the engine, it is unreasonable to think you will achieve anything near 100 mpg.

The exact theoretical mileage would depend upon the drag coefficient and the frontal area - neglecting rolling friction and other non-aerodynamic losses.

By far the easiest way to extend mileage is to slow down.  The mileage decreases with the cube of velocity.  It takes 4 times the force and 8 times the power to double the speed of a vehicle.  The difference between 55mph and 70mph is very significant.

So how much energy from the gasoline that was not vaporized well enough to burn in the engine (that could have been used to move the vehicle farther) is being wasted in the catalytic converter, by generating large amounts of wasted heat in the tail pipe?  There may not be 200 MPG in the gasoline, but I would sure take 60 MPG over 20 MPG.   

[jake]

So how much energy from the gasoline that was not vaporized well enough to burn in the engine

This was answered before - I don't know what "complete vaporization" means, but I believe automan is fundamentally right - fuel injection is a pretty exact science at this point.

Fuel systems today  are highly efficient in atomizing fuel. But they have to maintain that 14/1 ratio. High preasure fuel pumps, fuel injectors, and computer control systems do that much better than any carburator can.(and are twice as expensive too)  For the most part, complete voporization of gasoline has been achieved long ago. Any gains in fuel milage have to come from reduced friction, areo dynamics,
and converting heat into mechanical energy.

There has been a lot written about the "unburned particulates" furnishing the extra fuel for the extra 50 mpg or so, but if you check the Fish dynatune emissions levels you?ll see there aren?t enough of them to get you another 300 yards down the road.

I don't know about this either, but I suspect again that it would be true.

but I would sure take 60 MPG over 20 MPG.

Buy a very small car with no air conditioner or extra equipment and drive very slowly.  Better yet, a 125cc motorcycle will probably do it.

Back in the early 80's there were cars available that were getting in the high 50's.  People don't want the high mileage bad enough to get out of their SUV's.

[Liberty]

I did some quick research on the operating temperature of a catalytic converter.  It operates in the 2300 degree area.  The heat provided by the engine is in the 900 degree area.  That means that the exhaust is constantly producing a 1400 degree heater in the tail pipe.  Now if some very intelligent person could use that wasted energy and turn it into useful motion, we could go further down the road.  I would think that it could at least make some steam???

[lancaIV]

That is the function of the "Recuperator",
for example www.proepowersystems.com

S
  dL

p.s.:Only anything that I do not understand is Mr.Proeschel`s statement about "low cost"-technology,
his estimation "only" 500-750$/KW !
"Machine-shop-production-level !"