renders it possible to control the operation of engines, to obtain some idea of the cause of defects and to attribute them to the proper force. Improvements can then be made which will ensure a greater efficiency. A number of records herewith reproduced illustrate the defects in the controlling apparatus and in the construction of certain engines, and also the result of improvements which have been made on the basis of the records obtained. The smaller lines indicate the compression, which is usually constant in engines in which the "hit-and-miss" system of governing is employed, while the larger lines indicate the explosions. These records are only part of the complete data normally drawn on the paper in the period of 120 seconds corresponding with an entire revolution of the recorder-drum.
Fig. 146.—Record with automatic starter.
Fig. 147.—Gas-engine running at one-half load.
Fig. 148.—Record made after correcting faults.
Fig. 149.—Record made after correcting faults.
The first record was taken while starting up an engine provided with an automatic starting device and supplied with explosive mixture without previous compression (Fig. 146). The gradual lessening of the distances of the ordinates or lines representing the explosions shows that the speed of the motor was slowly increasing, and also indicates the time which elapsed before the engine was running smoothly. The records that follow (Figs. 147, 148 and 149) show the results