Internal Combustion Engines

The most transportable and rugged sources of power are IC engines. Most industrial internal combustion (IC) engines in the low-power range, about 30 hp or less, are gasoline powered because diesel engines are too heavy and costly. For example, in a small engine-powered water pump, a gasoline engine would account for perhaps 60% of the cost of the total package. With diesel power, the cost would be closer to 90%. Thus, in the low-power range, the choice of engine centers largely on such factors as a choice between four and two-cycle operation and between cast-iron or aluminum construction. is generally the preferred gasoline power plant. It has a reputation for long, trouble-free operation, idles smoothly and operates well at low speeds, does not require lubricant in the fuel, and generally does not have an exhaust with visible smoke. Small engines are normally air cooled for simplicity and weight savings. However, water cools larger, stationary engines most efficiently. Up to about 40 hp, four-cycle engines usually have simple L-head valve arrangements, which are less costly than an overhead cam. The overhead-cam arrangement provides more power and fuel economy and is generally found in larger engines. Small engines use the same simple breathing mechanism and carburetor found on automotive engines. More