Prognostic for loss of high-voltage isolation

A method for predicting a loss of high-voltage circuit isolation within a hybrid vehicle having a chassis and a high-voltage bus, the method comprising:

• determining whether a predetermined independent variable event has occurred;
• measuring and recording an equivalent resistance value taken between said chassis and said high-voltage bus;
• storing said value in a storage array until said array reaches a predetermined sample population;
• performing a data fitting analysis on said sample population to detect a trend in said population;
• and
• using said trend to calculate the number of said independent events remaining until said equivalent resistance is less than a predetermined threshold value.

An apparatus for predicting a loss of high-voltage circuit isolation within a hybrid vehicle having a chassis and a high-voltage bus, the apparatus comprising:

• a controller having memory and a control algorithm for predicting a high-voltage isolation fault;
• a plurality of high-voltage bus components operatively connected to said high-voltage bus;
• and
• a reporting device operable for reporting said predicted high-voltage isolation fault;
• wherein said controller is configured to initiate said algorithm upon the occurrence of a predetermined independent event, said algorithm including recording into said memory a series of periodic measurements of the equivalent resistance between said chassis and said bus, and predicting the number of said events remaining before said resistance reaches a predetermined threshold.