New Principle in I.C. Engines
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THE internal combustion engine has, for 50 years, remained unchanged in principle, although many constructional improvements have in that time been made. A new basic combustion system is shown in patent No. 690,805,
E. Houdry, Mill Creek Road, Ardmore, Pennsylvania, U.S.A.
The conventional engine develops a high peak-pressure at the moment of firing, and this gradually diminishes as the piston descends. This means that the engine must be strong enough to withstand the peak, although the mean effective pressure may be much lower.
The patent discloses a means for creating low-temperature combustion which avoids all the problems connected with detonation, explosion and flame
damage. In addition, the scheme is said to work well with fuel-air mixtures of all strengths, whether normally inflammable or not, and much higher compression ratios can be used. The scheme uses a catalytic material which oxidices the fuel at a temperature not exceeding 850° C. creating a pressure of up to 100 atmospheres.
In the working cycle of the engine, at bottom-stroke pre-compressed air is blown in through a port in the cylinder wall. At the same time, some of the exhaust gases escape from another port but complete evacuation is not necessary, On the upstroke, the compressed air is forced through a one-way valve into a pressure generator. A constant supply of fuel is also fed to the generator by a pump regulated by a by-pass.
In the chamber, a catalytic material enables the fuel and oxygen and fresh fuel to combine at a comparatively slow rate and so generate a high pressure. The gas is then admitted to the cylinder via an inlet valve operated in the usual way. The engine follows steam-engine practice in its working, the inlet giving an early cut-off to allow of work being done by expansion.
The gas enters the cylinder at about 680' C. and leaves at 150° C. At these low temperatures there is no carbon deposit and lubrication becomes no longer a problem. Copper is mentioned as a possible material for the catalyst.