Figure 2-24. Measuring Crankshaft Rotation

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Multicylinder Engine Versus Single- Cylinder Engine.

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TM-9-8000 Principles of Automotive Vehicles Manual

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Figure 2-26. Power Delivery in One-, Four-, Six-, and Eight-Cylinder Engines

TM 9-8000

Figure 2-24. Measuring Crankshaft Rotation

is actually more than one engine, all operating a common

Figure 2-26 also demonstrates how the equally spaced

crankshaft. Engines in automotive use are usually built

power strokes in a four-cylinder engine reduce the

using four-, six-, or eight-cylinder engines. Whenever

periods when the flywheel is carrying the engine. With

engines are built with more than one cylinder, it is

four power strokes for every 720 degrees of rotation, one

important that the cylinders give their power strokes in

can be made to begin every 180 degrees. This leaves

equal increments of crankshaft rotation. Figure 2-25

the engine with four equally spaced periods of 35

demonstrates

some

typical

multiple-cylinder

degrees each that the flywheel must carry the crankshaft.

configurations.

If the engine has more than four cylinders, the power

strokes overlap, meaning that before one power stroke is

Figure 2-26 illustrates how much of the engine rotation is

finished, another one begins. As illustrated in figure 2-

taken up by power stroke in a one-cylinder engine.

25, a six-cylinder engine has a 25-degree power overlap

between cylin-

SIX-CYLINDER ENGINE

FOUR-CYLINDER ENGINE

Figure 2-25. Typical Multiple-Cylinder Configurations.

2-18