THE THERMODYNAMICS OF THE MARINE OIL ENGINE. 87 



It is a fact that through the lower compressions in the cyhnder Mr. Wentworth speaks 

 of, you are able to obtain reliable and continual service without the maintenance of an enor- 

 mous series of valves and cams, and the setting of these valves and cams, as in the high- 

 cylinder compression that has been formerly used, necessitating a very tedious, insecure and 

 unreliable system of lubrication. Owing to the high-compression pressure of some of the 

 Diesels which have been put in service, we found it was almost impracticable to lubricate 

 the cylinders all the time. In one case en route from London to New York, we had always 

 the question of lubrication of the pistons. If we could do that, we would get to New York 

 on schedule time. By the lower compression we obviate that condition, also the high tem- 

 peratures created by high compression, and by the breaking up of the oil with a mixture of 

 air you can get complete combustion at a lower-compression pressure which follows the 

 curve of temperature. 



Mr. Howell: — How do you handle the question of compression in the cylinder? I 

 have seen a patent in which there was a plunger arrangement so that the compression could 

 be changed in the cylinder of the Diesel engine or gas engine, but it seemed to complicate 

 the apparatus, and when you consider the number of valves and fittings and cams on the en- 

 gine now, it seems to complicate and add more apparatus. 



Mr. Wentworth : — If your imagination will allow you to consider this a valve-cam 

 going this way (drawing diagram on the blackboard) I will show my method of procedure. 

 I had two cams — it was an experimental engine, a single-cylinder engine — one cam here, 

 representing partial load, and this representing full load. This would take in the full cylin- 

 der here (indicating) and this one the partial load. That would give a pressure of com- 

 pression of about 390 pounds. I think the way to get the best results would be to keep this 

 valve-cam constant; here is your fulcrum and here is the cam action. This valve is held seated 

 by this heavy spring and also by this light spring. If you depress this heavy spring (indi- 

 cating) , then you have nothing but an automatic valve spring to hold the valve tight. Then 

 if this is rotated with regard to your cam shaft, this action will not amount to anything, ex- 

 cept to close the valve; in other words, this will close the value and the automatic, light spring 

 will let it open at the proper time. This would seem to be a complicated way of arriving at 

 it on a fuel valve to provide for injection — that was the original form and we modified it. 

 This connection was broken and a rounded seat made in here. I had a hand wheel put on so 

 that I could pull one side or the other. In other words, here is the center line and here is the 

 point. That was broken there and brought over this way, and in that way I can get direction, 

 but at the same time it enabled me to vary the fuel injection, without any great expense, on 

 the experimental model. We started with the fuel injection at the dead point. That would 

 enable us to get an engine running. Once we got the engine running, got things warmed up 

 by this means, we could advance the injection and still keep the engine running. 



Mr. Wentworth (Communicated) : — Examination of the stenographic report of this 

 discussion brings out a few points which escaped my notice during the discussion on the floor. 



First, in regard to the remarks of Mr. Howell on sooting which he found to make the 

 use of exhaust gas impracticable as a means for generating steam, let me quote from the 

 Power of June 30, 1914, page 921, the correspondent said to have been chief engineer of a 

 Diesel ship for the past eighteen months. 



