RELATIVE MANIFOLD VACUUM OF AN INTERNAL COMBUSTION ENGINE

摘要

Relative Manifold Vacuum of an Internal Combustion Engine The instantaneous values of intake manifold vacuum in an internal combustion (IC) engine running under load are measured to provide an indication of the relative performance and relative suction ability of each cylinder in the engine. The instantaneous values of manifold vacuum are sensed at selected, sub-cyclic crankshaft angle intervals within a full engine cycle, each angle interval being substantially less than that associated with a cylinder sub-cycle, each sensed value of manifold vacuum being identified by the sensed angle position to provide an indication of the sub-cyclic fluctuations in manifold vacuum as they occur at known cylinder intake strokes within the engine cycle, thereby providing identification of each sub-cyclic fluctuation in manifold vacuum as being associated with a particular cylinder, the relative magnitudes of the manifold vacuum fluctuations providing a relative indication of each cylinder's performance and suction ability within a common engine cycle.