This paper proposes a technique for on line detection of cylinder-to-cylinder nonuniformity and incipient misfire by instantaneous angular velocity signals in automotive engines.

There from it is used to obtain the principles of the angular of momentum of the system of particles with respect to its cenier of mass and instantaneous center of velocity.

In accodance with kinetic energy theorem, this paper presents an angular mo- mentum theorem of velocity instantaneous centre axis. This theorem is a simple and convenient scalar equation.