| 摘要 |
The normal procedure for determining top-dead-center (T.D.C.) of a reciprocating engine involves slowly rotating the crankshaft of the engine until the maximum uppermost position (T.D.C.) of the piston in the cylinder has been attained and then inserting a linear gauge in the cylinder to make an appropriate measurement of this position. This method requires access to the piston crown and necessitates the disturbance of cylinder head components. The procedure disclosed obviates the deficiencies of the prior art by determining piston position from measurements taken externally of the engine, in particular by monitoring the speed of the engine, preferably using the flywheel of the engine, on a freely decelerating engine in a non-firing mode. The successive minimum speeds attained by the flywheel during a reciprocating cycle correspond to the two opposite extremities of movement of the piston in the cylinder of interest and thus accurate determination of T.D.C. and/or B.D.C. conditions is possible.
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