Method for graphically displaying vehicle test data

A method of automatically graphically displaying, on a display screen, emission test data collected and stored by an engine analyzer, the method comprising the engine analyzer performed steps of:

• generating and displaying on the screen at least one time-based first waveform representative of gas emission output levels of at least one selected ingredient gas, which levels are collected, measured and stored by the analyzer during a first emission test;
• and
• generating and displaying on the screen, superimposed over said at least one first waveform, a speed-correlation drive-trace waveform representative of one of an actual and an ideal drive trace of the relative speed of the vehicle at appointed time intervals during the first emission test.

An apparatus for automatically graphically displaying vehicle emission related data on an engine analyzer display screen, comprising:

• means for generating and displaying on the screen at least one time-based first waveform representative of gas emission output levels of at least one selected ingredient gas, which levels are collected, measured and stored by the analyzer during a first emission test;
• and
• means for generating and displaying on the screen, superimposed over said at least one first waveform, a speed-correlation drive-trace waveform representative of one of an actual and an ideal drive trace of the relative speed of the vehicle at appointed time intervals during the first emission test.