초록 ▼

This invention relates to a method and apparatus for diagnosing faulty cylinders in internal combustion engines. A probe produces a signal that is representative of the instantaneous angular velocity of the engine shaft. A Percent Power Contribution (PPC) parameter is computed by substracting the sq

This invention relates to a method and apparatus for diagnosing faulty cylinders in internal combustion engines. A probe produces a signal that is representative of the instantaneous angular velocity of the engine shaft. A Percent Power Contribution (PPC) parameter is computed by substracting the square of the instantaneous angular velocity at the beginning of a cylinder period from the square of the instantaneous angular velocity at the end of that cylinder\s period and dividing this difference by the square of the average engine angular velocity. A value of this PPC parameter significantly less than zero indicates a faulty cylinder. An Average Energy Percent parameter (AEP) is computed by dividing the squares of the sampled instantaneous angular velocity values summed over a cylinder period by the number of samples in that period and by the square of the average engine angular velocity. A value of this AEP parameter significantly less than one indicates the previous cylinder in the firing order is faulty. The two parameters can be used independently or in combination to diagnose continuous and transient engine faults. Faulty cylinder indications are displayed on a monitor or communicated to an operator.

대표청구항 ▼

An apparatus for diagnosing a faulty cylinder in an internal combustion engine comprising: a probe means for producing an electrical signal representative of instantaneous engine angular velocity; means for converting said electrical signal to discrete measures of instantaneous angular velocity at N

An apparatus for diagnosing a faulty cylinder in an internal combustion engine comprising: a probe means for producing an electrical signal representative of instantaneous engine angular velocity; means for converting said electrical signal to discrete measures of instantaneous angular velocity at N predetermined times during a cylinder period where N is an integer greater than two; means for averaging said measures of instantaneous angular velocity to produce an average angular velocity by summing an integer number of said measures of instantaneous angular velocity and dividing that sum by said integer number; means for computing a PPC parameter from said measures of intsantaneous angular velocity for each cylinder period by subtracting the square of the measure of instantaneous angular velocity at the beginning of a cylinder cycle from the square of the measure of instantaneous angular velocity at the end of that cylinder period and dividing that difference by the square of the average engine angular velocity; means for declaring a possible cylinder fault when said PPC parameter is less than zero.