Page:International Library of Technology, Volume 93.djvu/152

 The line j'k' of the indicator diagram D is identical on the down stroke with the exhaust line jk of diagram d, and on the up stroke there is an almost imperceptible rise of the low-pressure exhaust line w', exaggerated in the figure, above the atmospheric line O'V', due to the resistance of the exhaust passages.

45. The series of operations of the complete cycle in three-cylinder compound engines are as follows:

COMPOUND-ENGINE CYCLE

Cylinder h

Downwards; suction; inlet valve Open. Upwards; compression; ignition; combustion; both valves closed. Downwards; expansion; both valves closed. Upwards; exhaust valve open; exhaust into H.

Cylinder H

First Revolution

First Stroke

Upwards; exhaust; exhaust valve open.

Second Stroke Downwards; expansion; inlet valve open; exhaust gas entering from h'.

Second Revolution

Third Stroke Upwards; exhaust; exhaust value open.

Fourth Stroke Downwards; expansion; inlet valve open; exhaust gas entering from h.

Cylinder h'

Downwards; expansion; both valves closed.

Upwards; exhaust valve open; exhaust into H Downwards; suction; inlet valve open. Upwards; compression; ignition; combustion; both valves closed.

46. Automatic Cut-Off Engine. — The principal difference between the cycle of the automatic cut-off engine and that of engines operated on the ordinary four-stroke cycle is that the fuel supply is cut off during the suction