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This study evaluated the contribution of exhaust valve leakage to exhaust hydrocarbon (HC) emissions. A simple procedure was instituted to measure exhaust valve leakage rates under static, prescribed conditions. This standardized leakage rate was experimentally related to the actual increase in exhaust HC emissions. An analytical model of exhaust valve leakage was developed to complement the experimental effort.

Lubrication analysis of piston skirts is a complex problem because of elastic and thermal deformation of the skirt, mixed lubrication, and surface geometry. Several analysis methods have been developed at General Motors over the years for carrying out the piston lubrication analysis. These methods differ in how much of the complexity is modelled. This paper briefly describes these methods and compares the friction prediction of each of these methods with data from an experimental rig designed to measure piston-assembly friction. In addition, results are presented to demonstrate the effect of some design parameters on the lubrication performance of a piston skirt.

The flow of oil into a rotating crankshaft has been investigated. Analysis of the physics of the problem together with dimensional analysis indicates, for a given journal geometry, that a relationship exists between Reynolds number, non-dimensionalized pressure drop, and oil flow. Data obtained from an oil flow test rig are used to determine explicit correlations for two oil feed configurations; one journal with and one journal without a lead-in groove.