THE THERMODYNAMICS OF THE MARINE OIL ENGINE. 83 



the compressed air when this air is cooled to room temperature in place of being 

 used at 1040° F. absolute or 580° F. glass temperature. This waste is worth con- 

 sidering since it is a percentage of 10 per cent of the power of the main engine. 



If the injection air is used at this temperature of 580° F., just one-half of 

 the fuel to run the air compressor will be saved, and there will be no difference 

 in the operation of the engine. Before this can be wisely done, however, there 

 is need for a redesigning of the fuel valve. The writer has done some work along 

 this line, but unfortunately has nothing of value to offer at this time. It is his 

 opinion that the valve should be simplified even if the pump is complicated. All 

 valves of which the writer has any knowledge depend more or less upon capillary 

 attraction. In other words, the present fuel valve is in its general principle and 

 relation to the fuel pump nothing but the Brayton valve shown by Brayton in 

 1890. This is nothing against it more than the fact that Brayton was plowing 

 virgin territory, and fifteen years of operation show need for a redesigning of 

 the fuel-feeding arrangement of the engine. 



In regard to the danger in using air of this temperature there is this to say : — 

 Any explosion in the injection line will come from a quick opening of the air 

 valve. If there is a pocket in the line where oil can settle and the air valve is 

 suddenly opened with no pressure in the line, the body of oil will be dislodged 

 from its pocket and shoved along ahead of the incoming high-pressure air com- 

 pressing the low-pressure air. If this action in the injection line takes place quickly 

 the body of oil will take the place of a piston, and the action in the injection line 

 will be the same as in the cylinder during the compression stroke. A temperature 

 of ignition will be reached in the injection line regardless of the temperature of 

 the injection air. In fact the explosion is caused not by the injection air but by 

 the contents of the air line when the high-pressure air is turned on. It is possible 

 to safeguard this type of engine from explosion in the injection line by a little care 

 in the design of the piping arrangement, etc., and the exercise of due caution in 

 operation. 



The present instructions for operation of the Diesel engine state that the cool- 

 ing water from the jacket of the fuel valve should be cold to the hand. The 

 writer feels that the fuel valves can be designed so that it needs no jacket what- 

 ever. This may be objected to as an unsupported opinion, but it is based upon 

 years of study along this line of work during which nothing has been found to 

 oppose this idea and everything points to its possibility. 



In closing let us consider the proposed thermo plant. 



The writer is aware that the trouble with reformers is that they tear down 

 without constructing and often leave chaos where order existed. For this reason, 

 after having criticized extensively the existing order of things, it is felt that a state- 

 ment of the writer's ideal might not be out of place. 



Before describing this ideal the writer wishes to make a plea for charitable 

 consideration. This does not mean freedom from attack, but merely freedom from 

 that line of comment which he has met constantly for the last twelve years. 



