초록 ▼

A system and method for the diagnosis and prognosis of cylinder power imbalance in an internal combustion engine utilizes cylinder firing times to determine a differential value indicative of the power imbalance. This differential value identifies a cylinder power imbalance condition and can be used

A system and method for the diagnosis and prognosis of cylinder power imbalance in an internal combustion engine utilizes cylinder firing times to determine a differential value indicative of the power imbalance. This differential value identifies a cylinder power imbalance condition and can be used in a one dimensional or a two dimensional analysis to predict future engine performance. In one embodiment, a trend parameter is calculated from the differential values over several test sequences at periodic mileage of the vehicle. The rate and magnitude of change or deterioration of the engine performance is indicated by the trend parameter. In another embodiment, a two dimensional trend array is evaluated using singular value decomposition to arrive at an eigenvalue transformation matrix used to obtain two trend variables related to the two principal eigenvalues at a particular engine operating hour/mileage. In one specific embodiment, the two trend variables are converted to polar coordinates in which the polar radius .rho. is indicative of the severity of the imbalance condition and the polar angle .theta. is indicative of the cause or of a change of cause for the engine power imbalance.

대표청구항 ▼

[ What is claimed is:] [1.] For an internal combustion engine having a plurality of cylinders and an engine control computer for controlling the operating conditions of each cylinder, a method for the diagnosis and prognosis of engine performance degradation, comprising the steps of:conducting a tes

[ What is claimed is:] [1.] For an internal combustion engine having a plurality of cylinders and an engine control computer for controlling the operating conditions of each cylinder, a method for the diagnosis and prognosis of engine performance degradation, comprising the steps of:conducting a test sequence at each of a plurality of selected engine operating hours/mileages to:determine the firing times of each of the engine cylinders; and calculate a differential value [Ci] corresponding to the firing time for each engine cylinder [i] relative to the firing time for the immediately prior cylinder in the engine firing sequence; andaccumulating the differential values for each of the enginecylinders as a function of the number of test sequence conducted; andcalculating a trend parameter for each test sequence based upon the accumulated differential values;evaluating changes in the trend parameter as an indication of a change in cylinder power balance conditions over a predetermined plurality of the test sequences; andstoring the trend parameter in memory as a function of the number of the test sequence.