The Energy Balance Sheet of the Internal Combustion Engine

The author has amplified and in some degree revised the treatment described in a series of articles published last year. He believes that the method is new. By presenting the energy balance sheet in the form of a triple account the quantities which cannot be directly determined appear as differences.

For the original articles the author had to fall back on tests of an Otto cycle engine of his own design, dated 1895, but his attention has since been called to an admirable Ph.D. thesis by J. S. Clarke of Birmingham University, the data in which he has been able to use for this paper. It is unfortunate that the indicating of high-speed engines is not yet sufficiently precise to allow of the application of the author's treatment. The production of an indicator capable of giving reliable diagrams up to 2,000 or 3,000 r.p.m. is a matter of great importance.