Graphical display of engine cylinder parameters

Claim 1

Apparatus for measurement of cylinder performance in an internal combustion (IC) engine, comprising: sensor means for providing sensed signals of the actual values of selected parameters indicative of cylinder performance over a selected set of engine cycles; signal processing means, responsive to said sensed signals for each cylinder and including memory means for storing signals, said processing means calculating and storing in said memory means a mean value signal and a mean deviation value signal for each set of sensed parameter signal data acquired from each cylinder; as characterized by: display means, responsive to said signal processing means for displaying visually, in rectangular coordinates, each cylinder's associated mean value and mean deviation value signal as dual parallel bar segments including a first bar representing said mean value and a second bar adjacent thereto and representing said mean deviation value, said first bar extending perpendicularly from said rectangular coordinate abscissa to a length representative of said mean value as indicated on a scaled ordinate, said second bar being generally centered about said first bar mean value and extending at either end to the actual peak value and actual minimum value obtained for the set of measured parameter data, whereby said dual bar segments provide four visual indices of cylinder performance including the parameter mean value, the minimum and maximum parameter values, and the parameter mean deviation value.