Stirling Engines Could Save a Lot of Natural Resources

The internal combustion engine has been accused of being an environmental nightmare and the cause of much pollution and fueling it the cause of much pollution and even wars. Many have advocated getting

rid of it, but it does something valuable to our society that we can't afford to get rid of.

Electric engines have always had a battery problem. And the batteries have to be charged by something.  But what if we could start on a path to something better?  Not a miracle cure for the world's ills but a small step in the direction of less pollution, noise and waste.without upsetting the status quo.

Progress is an evolutionary process.Something is invented and then people start using it and in the using and building of the item we find ways to improve it. The longer something is used, the cheaper it

becomes to make and the better it performs.

The Stirling engine has languished in obscurity because when it was invented it was impractical for most applications based upon power output compared to its weight and size. It was improved upon until the Internal Combustion Engine was invented with its much more powerful cycle. At which point industry abandoned the Stirling engine and it stopped evolving.

Before people knew about pollution, natural resources depletion, global warming and imported oil, the only performance measure that mattered was power to weight ratio. The internal combustion engine,

diesel or gas powered, got so far ahead in that race early on that it was the obvious choice to run our economy.

Today, in 2015, the internal combustion engine has been improving for over 100 years and is a wonder of technical evolution because it originally had better power to weight ratio or power density.  And the

Stirling is still a curiosity.

THE PROBLEM

Pollution is waste and it doesn't pay.  It costs money to make a mess and then costs more to clean up. So avoiding the mess is worth the cost of the wasted materials plus the cost of materials and labor to

clean it up, assuming that you can clean up back to pristine condition.

The amount of design and parts used to remove the pollution and noise from the internal combustion engine is a significant portion of its costs, the fuel that is wasted exceeds the fuel that is used.

THE CONCEPT OF TIDINESS

If you make noise, you need to muffle it. So if you make a noisy engine, you need a muffler and exhaust system. Stirlings don't make noise and so don't need mufflers.

If you burn fuel incompletely under varying pressure you need to treat the exhaust to remove the unburned fuel and undesirable pollutants that are produced. Stirlings burn fuel at low pressure under

consistent controllable conditions that allow for prevention of the formation of undesirable pollutant exhaust gasses.  The Catalytic converter is built into the combustion area so very little fuel is

wasted.

Stirlings use the heat produced from the fuel, so it is possible to run them on any heat source including Solar, Geothermal, gasoline, diesel, natural gas, propane, wood pellets, corn or anything that produces heat.

If you start and stop the combustion 2,000 times a minute, you need to use energy to run a complicated ignition, timing system, that will inject fuel, compress air and then light it at the right time.  Stirlings use a constant heat source that does not need constant attention and control. You just start the burner and let it burn until it is time to turn it off. Stilings don't need carburetors, fuel injection, intake manifolds camshafts, EGR valves, PCV valves, Timing circuits, distributors or sensors on the exhaust to name a few things that waste money to buy and fuel to run.

Internal Combustions Engines (ICEs) take in air, compress it, heat it until it expands, use some of the force of the expansion to produce horsepower, then dump most of the heat and pressure out of the exhaust manifold while the rest wanders around and gets into the bearings and other working parts of the engine.  Stirlings have the heat sensitive parts separated and protected from where the heat is used and the fuel is burned so they don't need the mechanical parts cooled and the compression is never released.

If exhaust gasses are exposed to lubricants then the lubricants become polluted and need to be changed.  Stirlings have hermetically sealed bearings that are never exposed to outside air or exhaust so they

don't need oil changes and the bearings operate at ambient temperatures so they last a long time.

Internal combustion engines have pistons that go up, down, up down (four strokes) but which only produce power on the least efficient part of one of the down strokes.  The Stirling produces power at the most efficient part of each and every up or downward motion of the piston. So one Stirling piston does the work of 8  Internal Combustion Engine pistons. Fewer parts doing more work.

Solutions

So how much cheaper would an engine be if it didn't need all the things we pointed out, like catalytic converter, ignition system, fuel injection system, camshafts, valves, water pump or oil pump?  How many

natural resources are used to build all those parts?  It is time to find out. Because, if you search Stirling Engines on the web, the one thing you will notice, is that THEY WORK,  but the design invented in 1816  just isn’t very powerful.

Engines have one basic function, they convert one type of energy into another.  That is it. The internal combustion engine takes gasoline or diesel and turns it into mechanical motion. The Stirling engine does

the same thing more simply.

The Stirling engine got stuck in an evolutionary backwater bereft of attention after the internal combustion engine was invented.  The higher power density of the internal combustion engine made it seem

the better choice.

Nobody was concerned about the complexity of the design or the inefficiency and pollution of the product because it performed a needed function as an engine. Bandaid solutions were hurriedly invented and applied to the Internal Combustion Engine to overcome its inherently unreliable, noisy and dirty nature.

It is as if someone invented Windows 1 and got to version 5 before people realized that GNU/Linux could be used and they were too invested to switch.

The Stirling engine doesn't have the problems that the internal combustion engines do but nobody could figure out how to make them as powerful.  The Stirling seemed hopelessly under powered but otherwise

very promising. Engines large enough to power ships were made. But the lower power density made them uncompetitive with the noisier smoke belching steam and then gas and diesel engines. Because time is money and fast is better than slow.

Stirlings have been made and operated in niche markets since their invention while the internal combustion engine has been the engine of choice,  polluting the planet and consuming vast resources as it has driven our economy.

Industrial evolution has addressed the major flaws of the Internal Combustion Engine.  Engineers design and build models that last longer,  invented components that fix its drawbacks and allow it to

produce more power and work more reliably. The engine still has the problems, we just don't notice them anymore. It would be much better for the planet if we didn't spend all the resources necessary to cover

up the problems of the Internal Combustion Engine.  It will never be more efficient to use four strokes to do the work of one proper stroke.

One curious property of the Stirling is that when you run it like a pump, it pumps heat from one side to the other.  Stirlings are efficient at liquefying air when used in this matter.  But with low power density they haven't been used for things like your refrigerator or your air-conditioner, where they would not use Ozone depleting gasses.

The Stirling is reliable; with only about 4 moving parts there is very little to break or go wrong.  If only it had power density comparable to the internal combustion engine it would save a massive amount of

resources and fuel.

At Last

Somebody finally did something with the Stirling design. Unfortunately it was the U.S. government.  They made it more powerful and so expensive that it can't compete with the lower costs modern

internal combustion engine. So Stirlings are the engine of choice in spacecraft and submarines.  I haven't been on either.

But, now there is a new design, that in addition to being powerful is also cheap and uses existing manufacturing infrastructure to make its parts.  But to build and promote it so that business will consider it

when they could just use the internal combustion designs that everyone has been using forever will cost some money.

I propose that this Stirling design needs to be built and used so that businesses will look at how much they can save by using it and the natural forces of the market can begin to cause its evolution into the

power source of choice and perhaps make a small dent in the dominance of the internal combustion engine.

You can research Stirlings and see that many different types have been tried and they do actually work. But every one of them suffers from a limitation in the working pressure and heat transfer area  which is

what governs the power output.  This design fixes those issues.

This design is just a modification in the layout that puts two Stirling engines back to back incorporating the Miller cycle so that the working fluid can be used at high pressure.  Just as the internal combustion engine obtains its power density from  operating with high pressure so can this Stirling.  The power density can be adjusted with the operating pressure. Theoretically making this Stirling engine more powerful than the Internal Combustion Engine.