Abstract
Abstract: The measurement theory shows that any intervention in one process will affect the true value measured. Because of this, it recommended for that intervention to be minimal. However, in many cases this is not possible. The paper presents the influence of a special built measurement spark plug that reduces substantially the adaptation costs of instrumentation, by removing the expensive tooling of the cylinder head. However, that induce an additional propagation wave which disturb the true shape of indicate diagram.
Keywords: burning room, indicate pressure, piezoelectric sensor, spark plug, measurement.