Fig. 24.—Showing Three Possible Though Unconventional Arrangements of Four-Cylinder Engines.
The six-cylinder type of motor, the action of which is shown at [Fig. 23], C, is superior to the four-cylinder, inasmuch as the power strokes overlap, and instead of having two explosions each revolution we have three explosions. The conventional crank-shaft arrangement in a six-cylinder engine is just the same as though one used two three-cylinder shafts fastened together, so pistons 1 and 6 are on the same plane as are pistons 2 and 5. Pistons 3 and 4 also travel together. With the cranks arranged as outlined at [Fig. 23], C, the firing order is one, five, three, six, two, four. The manner in which the power strokes overlap is clearly shown in the diagram. An interesting comparison is also made in the diagrams at [Fig. 25] and in the upper corner of [Fig. 23], C.
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Fig. 25.—Diagrams Outlining Advantages of Multiple Cylinder Motors, and Why They Deliver Power More Evenly Than Single Cylinder Types.
A rectangle is divided into four columns; each of these corresponds to one hundred and eighty degrees, or half a revolution. Thus the first revolution of the crank-shaft is represented by the first two columns, while the second revolution is represented by the last two. Taking the portion of the diagram which shows the power impulse in a one-cylinder engine, we see that during the first revolution there has been no power impulse. During the first half of the second revolution, however, an explosion takes place and a power impulse is obtained. The last portion of the second revolution is devoted to exhausting the burned gases, so that there are three idle strokes and but one power stroke. The effect when two cylinders are employed is shown immediately below.
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