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Preheated six stroke engine

Pressurize, heat, and inject water
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Start with the idea of a six stroke engine (like the one Leonard H. Dyer invented in 1915).

For those who are unfamiliar with the six stroke concept, the six strokes are as follows: air intake, air compression/combustion, combustion/power, air exhaust, water injection/boiling/steam expansion, steam exhaust.

Create two sets of exhaust valves: one set for air exhaust, and the other for steam exhaust. Also, there should be two exhaust manifolds, one for steam, and one for air.

After pressurizing water from the reservoir (or from the steam condenser), heat it using the hot air in the engine's air exhaust manifold. This very hot water is what's injected into the engine's cylinders for the fifth stroke of the cycle.

Since the water is very hot, (unlike the original six stroke engine concept, and unlike Bruce Crower's six stroke engine), very little thermal shock occurs when the hot water sprays into the cylinder and hits the hot cylinder walls and the hot piston.

This reduction in thermal shock is probably the most important aspect of this idea ... so if I'm wrong about this part, then I'll probably delete the idea as a whole.

Furthermore, due to the water's higher starting temperature when entering the cylinder, it takes a smaller amount of the engine block's waste heat, per unit mass of water, to boil that water. This is because more of the engine block cooling occurs due to the water's latent heat of vaporization, and less occurs due to heating cool water up to it's boiling temperature.

This means that a greater mass of water must be injected in order to remove the same amount of the engine block's waste heat.

Obviously, this means that a greater mass of steam is produced per cycle than if the water hadn't been preheated. Less obviously, this steam also has a greater temperature and pressure (both at the beginning of and at the end of the steam expansion stroke).

To take maximum advantage of the increased quantity and pressure of the steam produced, a steam turbine should be placed between the steam exhaust manifold and the steam condenser.

The increased mass and pressure of steam in the cylinder directly produces more engine torque than if the water hadn't been preheated.

I'm not sure of the best way to use the extra power produced by the steam turbine... if this is a hybrid car, we can simply hook it up to an extra alternator, and make electricity with it. Or, we could use it to power an air intake compressor.

Gearing it down, and using it to provide extra power to the driveshaft probably isn't a good idea, since that would be just too much added complexity.

goldbb, Mar 11 2010

Prior Art http://www.freepate...ne.com/2671311.html
[goldbb, Jul 28 2010]


       why not have a heat echanger that one side is against the exhaust and the other side is where the steam flows before condensing thus using most of the waste heat to heat the water.
Arcanus, Mar 11 2010

       Your last two paragraphs suggest this would work in a car - six stroke engines will never work in cars because of the large amount of water needed.
mitxela, Mar 11 2010

       why not? if you capture water from the steam and exhaust you lose very little water per cycle and maybe add a gallon of distilled water a week
Arcanus, Mar 11 2010

       Arcanus, there're two exhausts in the system, one for steam, and one for air. Would you mind clarifying your suggestion?   

       mitxela, Because I have a steam exhaust manifold, nearly all of the waste steam gets captured -- the steam which is left in the cylinder's combustion chamber (at the end of the steam exhaust stroke will remain there, and will mix with the air during the air intake stroke.   

       Since so much of the air exhaust's heat will be used for heating water, it should be easy to further cool the air exhaust enough to cause some of the moisture in it to condense.   

       Some of the moisture in the air exhaust will come from leftover steam, and some will have been produced by combustion. In other words, there's more water there than we used and lost. Thus, we don't need to condense *all* of the water from the air exhaust, only enough of it to cover our losses.
goldbb, Mar 22 2010


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