Some Notes on the Design,Development,and Production of High-Speed Compression-Ignition Engines

Abstract

The high-speed compression-ignition engine has now almost completely superseded the spark-ignition or petrol engine as the power unit for heavy goods-carrying commercial vehicles and public service buses and coaches.

The principal reasons for the popularity of this type of engine amongst users of commercial vehicles in general are, in the authors' opinion, due to: (a) the high thermal efficiency attained, which results in the maximum number of miles per gallon of fuel consumed, and (b) the high degree of mechanical reliability resulting in trouble-free operation for long periods.

The results that are being obtained to-day are the outcome of many years of careful and painstaking work in the designs office and the test laboratory, together with the practical experience gained in the operating field. Except during the war years, development work has proceeded steadily in this country since the late 1920's. No revolutionary changes have been made during this period, but combustion has been improved (resulting in higher thermal efficiencies), and the mechanical weaknesses of some of the earlier designs of engines have been eliminated.