CORNELL, AND SWENSON—GAS ENGINE VALVE SETTING.         43

GAS ENGINE VALVE SETTING.
W. H. Cornell, '93, and B. V. Swenson, '93, School of Mech. Eng.

The engine in question is the one in the electrical laboratory of
the University, and was put in for the purpose of running dynamos.
It is known as the ^^Cycle," and was manufactured by Henry Warden
of Philadelphia, under Atkinson's patents. The engine was set up,
but for some reason, refused to run.

Considerable time was spent on it, but with little success, and no
one seemed to be able to discover what the trouble was.

In January, 1893, we determined to make an investigation, and
if possible to locate the difliculty. When we began our work, the
engine would run, but on applying the friction brake, it was found
that all, or nearly all, of the power was used in overcoming the
friction of the engine.

At that time the chief difficulty seemed to be in securing the
ignition of the charges. Ignition is secured bv compressing the
charge, and thus forcing the gas into a small tube, closed at one end,
and heated to incandescence by the flame of a bunsen burner. The
difliculty was caused by the suction of the engine, which reduced the
bunsen flame to such an extent that the temperature of the tube was
too low to ignite the charge. The air holes of the burner were en¬
larged, giving a much better flame, and a gas bag inserted in the
burner supply pipe.    After this we had no further trouble with it.

We found the piping in a very defective condition, the jacket
water being admitted from the top of the cylinder instead of from
below^ making it impossible to keep the cylinder cool, and the gas
pipes so small and so full of elbows, as to seriously impede the flow.
The piping was changed, and a larger gas pipe inserted. It did not
appear, however, that the efiiciency of the engine was materially in¬
creased, and an investigation of the valve setting was begun.

An indicator was attached, and cards taken. Card No. 1, Plate
1, was taken, with the eng:ine in its original condition. As it was
taken with a 100 pound spring the faults of the valve-setting are not
very apparent. We then determined to use a 20 pound spring, and turn
the engine over by hand. Card No. 2 was the result. To understand
the cards, it is necessary to understand the action of the engine. By
referring to Plate 2 it will be seen that the valves are of the poppet

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