Frequently Asked Questions

What is LIM Technology?

LIM Technology is a small company trying to develop and perfect a simple new technology. Headquarters are in Baltimore.

What is this new technology?

A simpler smaller smarter engine which will cost less to build and less to use.

After 120 years of internal combustion, what could LIM have discovered which would justify such claims?

Since at least the 1930s, it has been known that by using direct injection, the 2 stroke cycle could be just as fuel efficient as the better respected 4 stroke cycle, and that one could use an oil bath in the crank case, just as in four-stroke engines. LIM discovered that by using a super charger delivering pressurized air at the top of the cylinder, while exhaust is released just above the piston, at the bottom of the combustion chamber, we could improve the scavenging process, operate the valve without any mechanism dedicated to making it open and close on a fixed schedule, and reduce the noise level from what is normal for an engine of the same power.

How can the valve work without a dedicated mechanism?

The pressure generated by the supercharger accumulates in the intake manifold. When the piston, near the end of the power stroke exposes the exhaust ports, pressure in the cylinder immediately declines to less than that of the intake manifold, so the valve opens against a mild spring, just from the pressure differential. The piston is still approaching bottom dead center (BDC) so yet more air is attracted to the growing volume of the cylinder. As the piston passes BDC, and starts to approach the top of the exhaust ports, air is still coming through the valve because of inertia, but the exit (exhaust ports) is shrinking, because the piston is rising, so the quantity of air in the cylinder increases until the pressure in the cylinder is about the same as in the manifold, so the light spring helps the valve to close. This can be seen in the Animation page of our website.

Have you been able to measure the pressure in the cylinder?

We haven't done that yet, but it must be enough, because we are injecting Diesel fuel into the cylinder and it is igniting every time, so there is enough compressed air there for the heat to start the combustion process. This is without any spark plug or glow plug, and works even when the engine is cold.

Besides the simpler valve system, are there other advantages?

Yes, compared to a 4 stroke engine, getting a power stroke from each piston on every revolution doubles the torque. Cooling the head is easier, because all the exhaust is leaving through the ports in the cylinder wall, and only fresh air passes through the head. Another valuable advantage is that oil stays cleaner and lasts longer.

Why would oil be any different?

There are three reasons for oil to perform better. These are: (1) because there is no need to lubricate the valve train, so no oil circulates in the head or around valve guides, and (2) The piston is longer, with a lower ring between the exhaust ports and the crank case, so any combustion gasses which squeeze past the compression rings follow the path of least resistance, to the exhaust, rather than into the oil in the crank case, so the oil is not polluted by the blow by gasses, which is the source of the acids which make old oil harmful to an engine, and (3) Since the oil stays at the bottom of the engine, it doesn't get as hot, so there is less breakdown from heat.

You said this engine is quieter; why?

Most 2 stroke engines have narrow exhaust ports, because the intake cannot come into the cylinder at the same location as the exhaust going out. All of our intake is through the one way valves in the head, so exhaust ports can be located all around the circumference in some engines, and around most of the circumference in others. This allows the exiting gasses to leave at a far lower velocity.

You said LIM engines will cost less to build and use, please explain.

This question has two parts, and more answers. First, LIM engines will cost less to build because there are fewer parts, like no expensive camshaft, no rockers, lighter valve springs and fewer cylinders and pistons, shorter crankshaft and smaller block. Second, they will cost far less to operate because they weigh less, so vehicle weight could be lighter. Oil would not need to be changed nearly as often, so that is a savings, and when a LIM engine idles, it is not driving the camshaft and its conventional valve train, so it can idle much less rapidly, using less than half the fuel usually needed for idling.

Everything you describe seems pretty basic; why wasn't this technology seen and developed sooner?

It is basic, but in the early days of developing internal combustion engines, not all of the parts and materials were available. 2 stroke engines were known in Europe before the US Civil War, but they could not be well lubricated, so they frequently seized. They also made too much smoke and noise. Around 1875 a German named Otto patented the 4 stroke process, which solved the major problems of the earlier known (2 stroke) engines, and consumed less fuel for its power output. By the late 1880s, automobiles, on the roads of Europe, were powered by Otto's four-stroke engines, and they proved to be better than the two-stroke engines of the time. In the 1890s, Rudolf Diesel introduced compression ignition engines which were 2 stroke engines, and they were also accepted, but were too expensive and too heavy at that time for cars. Locomotives with two-stroke Diesel engines are still pulling trains on almost every continent.

Beside our patented valve, another essential part, the supercharger, first became available around 1901, after four-stroke engines had dominated the market. two-strokes had already been pretty much displaced and there is no record of widespread use of supercharged two-strokes until the later 1930s. Many engines modeled after the supercharged two-stroke engines of the 1930s are still in use today.

What is the single most important part of your innovation?

That would be the self actuating pressure responsive valve. It makes possible the elimination of the valve train, a very expensive assembly, and eliminates the need for the camshaft, which is also very costly. Not only do those parts cost a great deal economically, but they add a great deal of friction and inertial resistance to the Internal Combustion process.

This doesn't sound like other 21st century innovations. What about electronics?

Electronics entered the automotive market in the 1970s, but they were mounted on engines which had not been much improved since electric starters replaced the old arm breaking starter cranks you see in museums.

Are you saying your new engines won't need any electronics?

Electronics could add some value, as they have to conventional engines. As soon as we learn some more about optimizing the proportions of the LIM engine, and have some more money, we would love to employ some of the right people to enhance our mechanically efficient engines with electronics.

Do you see specific uses for electronic enhancements?

Yes. We would like to set our engine up with modern common rail fuel injection and computer managed spring tension. We could also use a micro chip to manage alternating fuel injections during idling, so that still less fuel would be used than now.

What is this about spring tension?

In its latest products, BMW is introducing variable valve timing, which also includes variable valve lift, which means how far the valve can open, and how long it is open, and when it opens and closes. LIM engines have variable spring tension, which may delay slightly the opening time, accelerate somewhat the closing time, and limit the stroke of the valve. The way we do it with springs is far simpler and less expensive than the way BMW does it.

Are you saying you can make an engine lighter, more powerful and better than BMW?

No. We are saying that for far less money, we can make a lighter less expensive engine which can generate more torque and equal horsepower, than most conventional engines costing more.

Are you certain it will cost less to use?

Yes. It weighs less, which saves fuel. When it idles it doesn't have to drive a camshaft and valve train and push conventional valves against stiff springs. It only turns the crankshaft once to fire every cylinder, reducing friction even more. So, it idles very slowly, saving a great deal of fuel when in its "stand by" mode. Another saving is the cost of the oil you will so seldom change. Except for the fuel system, there is nothing to ever tune up, not even a timing belt. And if the belt driving the blower should ever break, just replace it; you won't lose any parts, damage anything, or even need a tune up. Its not like any other auto engine.

What about fuel cells and hybrids?

Fuel cells have been in the news for at least 45 years. The first fuel cell was invented before the Civil War. The fuel will still cost money. The system will be heavier than an equally powerful LIM type engine, and will cost a great deal more.

Hybrids... maybe they will make sense, especially with a light weight, reliable and economical LIM type engine to drive the generator.

When do you think this will be available in cars?

This is the toughest question to answer. Manufacturers will want ample proof, and unions will hate to give up any of the jobs which producing engines like this will make less necessary. We think the best way to get this technology into the auto industry is to first prove it in other markets which are more flexible.

What about other uses, like boats, aircraft, locomotives?

They will all make good uses for this simpler smaller smarter technology, but in locomotives we will settle for the same weight, and just make more power for less cost. In light aircraft, weight reductions of over 25% for the same torque delivered to the propeller, at a lower RPM, will make aircraft cheaper to power, quieter, able to carry better useful loads, and less expensive to operate.

You said you are confident of the air quantity and compression because the fuel ignites from compression. Does this mean that LIM's system is only for Diesels?

Our experiments so far have been with Diesel, but we couldn't do everything all at one time. There is more than one way to directly inject lighter fuel, like auto gas or aviation gasoline. We intend to do this when money is more available. Natural gas, propane and alcohol will also be viable fuels in LIM type engines.

What about the increasing cost of fuel, and its decreasing availability?

This is a serious long term problem for all humanity, but for the next quarter century, even though fuel may become more expensive, humans will continue to use engines for the muscle needed to do the world's work. Other systems may eventually become cost competitive, but if even only a small part of the world's work is done with engines, this is the engine which will be best justified economically. Investors in the development of this product should see the return on their investment many times over during the next twenty years.

Won't the oil industry do something to stop this kind of new technology?

This will be good for the oil industry. Although it will initially save fuel, the availability of less expensive more efficient engines will help to enlarge the rate of sale and production of new engines and vehicles. The old vehicles will just fall into other hands. There would soon be more consumers and therefore more consumption.

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