Parameter controlled speed determination in internal combustion engine diagnostics

Apparatus for testing the oil pressure system in an internal combustion engine as the engine accelerates while loaded only by its own inertia, drag and accessory loading, comprising:

• pressure sensing means adapted to be disposed to sense the pressure of the lubricating oil in the engine and provide a pressure signal indicative thereof;
• speed sensing means adapted to be disposed to sense the rotation of the engine and to provide a speed signal indicative of the speed thereof;
• and
• processing apparatus comprising means for sampling said pressure signal and providing pressure manifestations indicative of the pressure represented thereby a number of times during a time interval while the engine is accelerating and for determining the pressure at which the rate of oil pressure rise with speed begins to decrease.

In the method of diagnosing an internal combustion engine, the steps of:

• simultaneously sampling indications of speed in non-speed dimensions and indications of another parameter, repetitively, over a sufficient number of samplings so as to show a trend in the values of said other parameters being sampled;
• determining, from the trend, a parameter value of interest;
• and
• converting to speed dimensions the speed indication samples simultaneously with the parameter value of interest.

Apparatus for diagnosing an internal combustion engine, comprising:

• a transducer adapted to be disposed with respect to the engine to sense a particular parameter, said parameter having a characteristic profile with a point of interest thereon which can be determined by analysis of several samples of said parameter including said point of interest;
• speed sensing means, adapted to be disposed for response to mechanical movement of a portion of the engine in relationship to the angular revolutions of the engine, for providing successive measured data manifestations of the time elapsed during angular revolution of the engine through a known angle and therefore indicative of the speed of the engine as the engine rotates;
• and
• processing apparatus including means for repetitively taking samples of said transducer and of said measured data manifestations and for storing said measured data mainfestations for at least the interval of said several samples, for analyzing successive samples derived from said transducer and determining a sample of interest and for converting the one of said measured data manifestations relating to said sample of interest into a manifestation of speed expressed in speed dimensions.