FRICTIONAL LOSSES IN DIESEL ENGINES

After a short discussion of methods for measuring friction losses in diesel engines and the conclusion that it is not yet possible to determine accurately the true friction under firing conditions, motoring loss measurements for a number of automotive diesel engines of all sizes are presented. A simple formula that correlates this information is proposed.

The breakdown of the observed friction into its components is examined in detail, permitting better understanding of the makeup of the total friction and of design changes necessary to reduce losses. A simple piston friction rig used to examine design parameters is described.