Discussion on “diesel engines for generator drive” (Legrand), San Francisco, Cal., Sept. 17, 1915. (see proceedings for August, 1915)

Wilfred Sykes: It will be interesting to find out what Mr. Legrand´s experience is with the engines after they have been running for some time. From observations made in Europe I got the impression that considerably more attention had to be given to these engines than to other types of prime movers. The class of people used to operate them seem to be much better than is usually found in power houses and undoubtedly they are paid more money for their services. The successful Diesel engines seem to be those with comparatively small cylinders. The engines developing about 200 to 250 h. p. per cylinder run entirely satisfactorily. As the size of the cylinders is increased difficulties in manufacture and operation also increase. As far as my observation goes it is essential for the success of Diesel engines that they should be strongly built, should have good workmanship and not have too much power per cylinder. The attempts that have been made to build light Diesel engines such as are required for submarines have not been very successful. From the standpoint of reliability, a light Diesel engine has not given the service that would be considered satisfactory for land work. They have been used for submarines mainly because nothing better was available. Attempts are being made to get away from this type of prime mover where light weight is essential, and it is probable that in the near future the Diesel engine will be superseded for submarine work by the steam turbine, although the economy of the latter is not as good as that of the Diesel engine. In a number of plants which I investigated it seemed to be the common practise to take out the exhaust valve every week, and the statement was made that although very often there was no apparent reason for doing so, it was found that by following this practise and anticipating any troubles that might occur, more continuous service was obtained.