REFLECTIONS

A Brief Word


| July/August 1994



Theoretical card of Gas Engine

Fig. 1. Theoretical card of 4 stroke cycle gas engine

Since this column is being prepared somewhat ahead of the usual deadline, we did some searching through our literature collection, and offer some interesting articles to our readers this month. The first article is a treatise on the Buckeye double-acting tandem engine. This came from the November 1, 1908 issue of Practical Engineer. In reading this over, it becomes immediately obvious that gas engine design was well developed by this time, even though the practical four-cycle engine had been developed some thirty years earlier. Unfortunately though, this article says virtually nothing about the horsepower range and sizes of the Buckeye.

THE BUCKEYE FOUR-STROKE CYCLE GAS ENGINE

This term, 4 stroke cycle, signifies that 4 strokes are required to complete the action for the engine. The first stroke is occupied with drawing in a charge of air and gas is called the suction stroke. On the second this mixture is compressed and near the end ignition occurs. During the passage of the crankpin past the dead center the combustion or explosion takes place. During the third stroke the expansion of the hot gases is accomplished and during the fourth stroke the burned gases are exhausted from the cylinder, the series of events being as indicated in Fig. 1.

The requirements in arranging the gas engine are that the cylinder shall drain thoroughly, that the exhaust and admission valves shall be kept well apart and shall be so located that the exhaust stroke of the piston will drive out practically all the burned gas from the cylinder. These requirements are met in the Buckeye engine by placing the admission valves at the top and the exhaust valves at the bottom, as shown in Fig. 2. With the exhaust valves at the extreme bottom, oil and other deposits pass out directly through these valves. The incoming charge at the top is not mingled with the burned gases remaining near the exhaust valve in the bottom, and both exhaust and admission valves are placed so that they can be gotten at conveniently for cleaning and inspection.

For small sizes the working barrel is continuous from end to end, but the water jacket has an opening entirely around the circumference, this opening being closed by a cast-iron band drawn tightly around the cylinder. This construction allows of expansion and contraction with varying temperatures without causing strains in the structure. For larger sizes the cylinders are made in halves bolted together in the center.

The main frame of the engine is anchored firmly to the foundation but the rest of the machine is left free to move on fixed guides on cast-iron bases, as shown under the center distance piece and the slide for the rear tail rod.

Ignition and Governing