[evilgenius]

I have an idea about how to build an internal cumbustion engine that might get better mileage. I can't say for sure because I can't afford to build a prototype. I don't want to go into specifics because I don't want my idea stolen. I will elaborate a little, however.

I reckon that it is possible to put two opposing pistons in the same bore. This creates a different kind of more highly compressed combustion chamber. There must also be a different connecting rod setup. There is a leverage advantage to be gained by doing this that is not enjoyed in the conventional IC engine setup. Also, tricks can be done with the flame wall in the combustion chamber that can't be done conventionally either. In other words, more of what is on offer in a conventional setup can be actually used, rather than put out of the tailpipe.

I don't know if even my highest expectations being met would put much of a dent in the onset of peak oil, but things like this are worth a try. It might at least give hydrogen a fighting chance to get off of the ground.

If anybody has any ideas about who or what I could contact to get help developing my idea please post them here.

[Guest]

$this->bbcode_second_pass_quote('evilgenius', 'I') have an idea about how to build an internal cumbustion engine that might get better mileage. ...
I reckon that it is possible to put two opposing pistons in the same bore. This creates a different kind of more highly compressed combustion chamber.

[strider3700]

interesting reading. I'm guessing the added complexity and size requirements to combine the output from the two crankshafts is what limited it to marine applications

[Hegel]

Pretty old design. It wears down very quickly without using extremly precise manufactured pistons. You might looking into the Junkers turbo diesel engines "Jumo-Doppelkolben" designs instead. Besides, Lohner-Porsche engine/wheel designs of 1902 should be the most efficient post-p.o. solution.

[dukey]

i've thought long and hard about this myself

lets go back to the basics of combustion
in a car generally when the combustion occurs the piston is in the up position. The explosion causes the gas to expand driving the piston outwards. The friction inside the engine counters some of this force reducing it slightly. But wheres the majority of the efficiency lost ? Simple in the combustion itself. Something like 60-70% of the energy is lost as heat. It either goes straight out the exhaust as heated gases, or heats the engine block up then eventually gets blown out the radiator as waste heat. So you can almost think of cars as giant heaters with a side effect of moving the vehichle forward.

To visit the prius car, which is kinda interesting. It increases the efficiency by using the breaking power to turn a little generator to charge the battery. Normally when you break all the energy of the car is lost as heat in the break pads. But the prius uses this energy before its lost as heat or so i believe.

The key to making cars more efficient besides making them with smaller engines would be to use some of the waste heat. Maybe, you could use a stirling engine to cool the engine block instead of just blowing the heat out the radiator. Using that you could charge up a battery. You could possibly have one on the exhaust also. Only problem is this increases the complexity of the car design and also obviously its cost. Maybe we would all be better off riding 50cc motor bikes What are they .. 100 miles per gallon ? People never look at changing their life style as an amazing way to save energy.

[parainwater]

All things being equal and I repeat all things being equal. The Otto cycle
gasoline engine, Diesel cycle engine and Brayton cycle gas turbine engine's thermal efficiency is a function of only one thing and that is
compression ratio. Increased compression ratio means increased thermal efficiency. This is one of the reasons why Diesel engines get better mileage, the other reason is that Diesel fuel contains more thermal energy per unit mass than gasoline. The compression ratio relationship is asymptotic however at about 16 or 17 to 1.
Overall engine efficiency depends upon many other variables of course.
One must strive to minimize irreversibilities such as friction, poor combustion, back pressure, etc. as well as striving for higher compression ratio. Pump gasoline 89 octane is limited to about 9.0 to 1 compression ratio before detonation becomes a problem. One advantage to alcohol is that it has a high equivalent octane rating and thus allows higher compression ratios even though their is no octane in it. Alcohol has a lower thermal energy content than gasoline unfortunately. So the two tend to cancell each other out.

[aflatoxin]

Fairbanks-Morse (MEP) produced an engine that used horizontallu opposed pistons in the same bore. It was used on subs. THere was also a natural gas version produced that was used on compressors.

These were two-cycle engines. Most mechanics did not care for them. They are hard to work on. They produce a lot of power from a small, light package, and are very fuel efficient. I have more info (scanned drawings, etc) if you are truly interested. The NOx emissions from these engines are pretty bad.

Cooper-Bessemer made an engine long ago that had one piston in a cylinder with heads on both ends. The rod went through the head to a crossrod attached to the crank. These units had four cylinders, eight heads, and two rods. These units were basically steam engines reworked to burn natural gas.

I think there are some large marine engines that have opposing pistons. These use the smaller upper piston as valves

[dooberheim]

$this->bbcode_second_pass_quote('dukey', '
')The key to making cars more efficient besides making them with smaller engines would be to use some of the waste heat.

[Slowpoke]

Napier built the Deltic opposed-piston engine back in the 40's and 50's.

[evilgenius]

Thanks, everybody. I looked up some of the things you recommended.

I still wonder if anybody knows of any think tanks or companies that might be doing work along these lines.

To give a little more information. I did consider needing two crankshafts when I first had this idea years ago. Because that sounded too cumbersome and might add so much weight that it would render a small design inefficient I sort of let the idea tank. A little more than a year ago I reconsidered. It can be done with one crankshaft. In fact, it is the setup connecting the pistons to this single crankshaft which gives such a leverage advantage.

As for the valve problems, this too I considered might be a soul destroying failure to try to design. Now, however, with the advent of common rail injectors I think at least the intake problem is licked. Exhaust can probably be acheived because there is more room for it if the design uses common rail injectors. I reckon the engine has to be a four stroke. That means two cylinders minimum and probably three to run the smoothest.

Because of the length of the bore a second set of injectors can be added along the pistons travel for additional air or a secondary air/fuel mixture once the flame wall has reached the optimal point for secondary enrichment. Again common rail injectors make this possible. That is how I figure that even more efficiency can be wrung out of the design at the top end.

[aflatoxin]

If you really have an interest in things of this nature, I suggest that you obtain a copy of "The Internal Combustion Engine in Theory and Practice" by Charles Fayette Taylor.

This set of two books goes into a very detailed discussion of fuels, design, materials, thermodynamics, and other related topics. He includes standard recips of the two and four cycle variety, wankels, turbines and others. Everything from a cox model airplane engine to a 50,000 horsepower marine engine are discussed.

I can only imagine that the target audience for these books are grad students and engineers. The math is pretty involved at times. There are tons of pictures and diagrams, charts, etc.

These were pretty pricey a few years back when I had my company buy them. I imagine that they could be borrowed from a library, or read at the local niversity.

enjoy!

[Frank]

The best avenue to better mileage is still a smaller engine: exhaust heat can be used to drive a turbocharger to up the power levels. Running at higher throttle reduces pumping losses (gas engine), therefore higher efficiency. You still can't overcome the Carnot Cycle limitations though.

Toyota uses an Atkinson Cycle engine in the Prius - same technology in the Ford Escape and probably others.

[dukey]

http://www.gizmag.co.uk/go/4936/

just found that in the news
very interesting
maybe i should be a car engineer as i was only saying a week ago use the exhaust gases to improve the efficiency

[waveNRG]

How about abandoning the IC engine and going to a gas turbine engine (as has been done before by enthusiastic researchers, I know). ...a hybrid car with a gas turbine generator effectively.

If you have a miniature combined cycle gas turbine (like those used in natural gas powerplants), with the turboshaft connected to an electrical generator. The exhaust gases could be directed to a boiler, producing superheated steam that is then directed back to a steam turbine on the same turboshaft.

The car is then powered purely by electrical means with electicity generating brakes. (like a hybrid)

As the gas turbine engine is disconected from the wheels (like a hybrid I guess) it can run continuously at optimum rpm ...important for gas turbine engine efficiencies.

Of course there should also be a socket to charge the car off the grid as a preferable and cheaper way to power your car. Just spool the gas turbine up when the battery runs low.

Highly efficient (highly expensive), with the best advantage that your car will sound like a jet fighter. ....cool.

Anyway ...undoubtedly been considered before. Probably would have worked for trains already.

[BlueGhost]

The Car and internal combustion engine are always goinig to be terribly wasteful of energy.

Carrying your fuel and an engine around with you?
Burning a small amount of fuel?
Soft suspension?
Soft tires?

The transport system of the future is eather going to be horse and cart or it will:

Use electric motors. (Can generate energy when you break)
Travel along a very flat surface (no suspension)
Travel along a low friction surface (rails / maglev for example)
Produce very little wind resistace (vacume tunnels?)
Generate its power centrally if the electricity comes from heat production OR wherever is most efficient if it comes from wind/solar/tidal

[evilgenius]

Blueghost,

I got that. This idea is only brought up as something to bridge the gap. I don't think that the world can do in five years, from the time it finally wakes up, what realistically will take twenty or thirty. I think if we can pump up the fuel efficiency of automobiles to at least fifty miles per gallon we can gain a few years. A few years to come to consensus about the true effort that has to be done.

I've got loads of ideas about how to build high-speed over head suspension, to replace rail because it is so much cheaper and easier to put into place quickly, lines for mass transit. Gulf and Western tried a single line years ago but it was unstable. It isn't unstable if you mount the lines in tandem instead of singley.

Also it might be possible to extract hydrogen from water as a vehicle goes along. Using the same basic principle as a plant uses it might be possible to carry a tank of water and extract only the hydrogen required at the moment or a small store. A charged membrane would separate the hydrogen from the water. The technology for this has existed for quite a few years but is being used in a different field. Researched, as we need to research, and applied to this field and it means the end to the puzzle of how to store enough hydrogen on board the vehicle of the future. You would store water and expel oxygen from the hydrogen formation process. These same would be recombined to expel water from a fuel cell.

[Doly]

$this->bbcode_second_pass_quote('evilgenius', '
')Also it might be possible to extract hydrogen from water as a vehicle goes along. Using the same basic principle as a plant uses it might be possible to carry a tank of water and extract only the hydrogen required at the moment or a small store. A charged membrane would separate the hydrogen from the water. The technology for this has existed for quite a few years but is being used in a different field. Researched, as we need to research, and applied to this field and it means the end to the puzzle of how to store enough hydrogen on board the vehicle of the future. You would store water and expel oxygen from the hydrogen formation process. These same would be recombined to expel water from a fuel cell.

[evilgenius]

That is exactly the point. The amount of electricity used is minimal. The charged membrane doesn't exist yet, by the way, but with the proper amount of research the priciple should hold. The field that uses the technology is geologic prospecting (also alternative medicine,- the rife machine). The technology is molecular frequency discrimination. It isn't so much about forcing hydrogen to separate from oxygen as it is about coaxing it the way that nature does.

[Aedo]

$this->bbcode_second_pass_quote('evilgenius', 'A')lso it might be possible to extract hydrogen from water as a vehicle goes along. Using the same basic principle as a plant uses it might be possible to carry a tank of water and extract only the hydrogen required at the moment or a small store. A charged membrane would separate the hydrogen from the water. The technology for this has existed for quite a few years but is being used in a different field. Researched, as we need to research, and applied to this field and it means the end to the puzzle of how to store enough hydrogen on board the vehicle of the future. You would store water and expel oxygen from the hydrogen formation process. These same would be recombined to expel water from a fuel cell.

[evilgenius]

Think of the examples in nature. Plants don't need that much energy to separate hydrogen. This isn't electrolysis. The membrane would be enzymatic. The return wave from the MFD would only serve to turn the membrane on or off. Yes, you would need to input new energy into the system as you went along but not nearly the amount you are suggesting.