Patent ID: 6085142
Filing Date: 2000-07-04
Classification: F02D

Abstract:
A method of calibrating an injection system associated with an internal-combustion engine (M) controlled by an electronic processing unit (ECU), the injection system comprising a plurality of injectors (I) for admitting fuel to a plurality of cylinders of the engine (M), the method enabling the processing unit (ECU) to operate the injectors (I) in a manner such as to admit a precisely known quantity of fuel to each cylinder in the presence of injectors (I) having different flow-rates,the method comprising the steps of:operating the engine (M) with the injectors (I) operated with identical open times,detecting a torque pulse supplied by each cylinder of the engine (M),determining the flow-rate of each injector (I) on the basis of the torque pulse detected,storing data relating to the flow-rates of the injectors (I) in a memory of the processing unit (ECU),using the data stored relating to the flow-rates of the injectors (I) in the course of the normal operation of the engine (M) as factors for correcting the open times of the injectors (I) so as to compensate for the different flow-rates of the injectors (I);characterised in that it also comprises the step of measuring the compression seal of each cylinder and compensating the torque pulse measurements on the basis of the determined compression seals;the compression seal of each cylinder being determined by calculating the resisting torque value for each cylinder as the average of a plurality of resisting-torque valves determined for each cylinder after the engine (M) has been switched-off and while the engine speed and the engine temperature are comprised within respective predetermined ranges.