Method and apparatus for timing diesel engines

Abstract

The specification discloses an improved method and apparatus for determining the time angle of a diesel engine which, in contrast to the present day method, is one which is fast, accurate, and can be readily used on a production line basis. There is disclosed a method and apparatus which, by the utilization of pulses of fixed angular frequency produced by an encoder, and counted between the moment the pressure in the injector line of the cylinder, whose timing angle you are measuring, reaches a predetermined pressure and the moment the piston in the same cylinder reaches top dead center, a number of pulses representing the timing angle of the engine is obtained, which can easily be converted into a reading of the timing angle. The pulses are essentialy counted by producing a signal when the pressure in the injector line reaches a certain predetermined value, after which time all other pressure signals are locked out in a predetermined manner, with the count of pulses being stopped when the next top dead center signal occurs. By providing a lockout period based on degrees of crankshaft rotation for all timing applications, except where the engine being timed in intended to be run at a constant speed, a production diesel engine timing system is provided which gives accurate results, regardless of the speed of the diesel engine, in an accurate and reliable manner.