초록 ▼

A method and apparatus are disclosed for diagnosing faults in individual cylinders of an internal combustion engine. An engine (12) is accelerated, while an analyzer (10) provides measurements of the time intervals required for the engine to rotate for successive, equal angular increments as the eng

A method and apparatus are disclosed for diagnosing faults in individual cylinders of an internal combustion engine. An engine (12) is accelerated, while an analyzer (10) provides measurements of the time intervals required for the engine to rotate for successive, equal angular increments as the engine is being accelerated, where each increment is a fraction of the rotation required for a single engine cylinder power contribution. The values of the resulting sequence of time interval measurements generally undulate with time about an average value due to the power contribution of each individual cylinder, with the average value of the time interval measurements and the magnitude of the undulations about this average value generally decreasing with time due to the acceleration of the engine. The analyzer (10) modifies the time interval measurements in the sequence so as to provide a modified sequence having a substantially constant average value and substantially constant magnitude of undulation. The analyzer (10) then compares the characteristics of the individual undulations in the modified sequence so as to diagnose faults in the individual cylinders in the engine.

대표청구항 ▼

A method of diagnosing faults in individual cylinders in an internal combustion engine, comprising the steps of: accelerating said engine, measuring the time intervals required for the engine to rotate through successive, equal angular increments as said engine is being accelerated, each increment b

A method of diagnosing faults in individual cylinders in an internal combustion engine, comprising the steps of: accelerating said engine, measuring the time intervals required for the engine to rotate through successive, equal angular increments as said engine is being accelerated, each increment being a fraction of the rotation required for a single engine cylinder power contribution, thereby producing a sequence of time interval measurements the values of which generally undulate about an average value due to the power contributions of individual cylinders, and wherein the average value of said time interval measurements and the magnitude of the undulations about the average value generally decrease with time due to the acceleration of said engine, modifying values corresponding to said values of said time interval measurements in said sequence so as to provide a modified sequence having a substantially constant average value and magnitude of undulation regardless of the acceleration of said engine, and comparing characteristics of individual said undulations in said modified sequence so as to diagnose faults in individual cylinders in said engine, wherein said step of modifying includes the steps of matching a first regular, monotonic function to selected peaks of said undulations, matching a second regular, monotonic function to selected valleys of said undulations, and utilizing said first and second matched functions to modify said time interval measurements. Apparatus for diagnosing faults in individual cylinders in an internal combustion engine as the engine is being accelerated, comprising: means responsive to rotation of said engine for providing a plurality of successive signals each having a value indicating the time interval taken by the engine to rotate through a corresponding one of successive, equal angular increments as said engine is being accelerated, each angular increment being a fraction of the rotation required for a single engine cylinder power contribution, thereby producing a sequence of signals the values of which generally undulate about an average value due to the power contributions of individual cylinders and wherein the average value of said signals and the magnitude of the undulations about the average value generally decrease with time due to the acceleration of the engine; means for modifying the values of said sequence of signals so as to provide a modified sequence having a substantially constant average value and magnitude of undulation regardless of the acceleration of the engine, and for comparing characteristics of individual said undulations in the modified sequence so as to diagnose faults in individual cylinders in the engine.