Leak and blockage diagnostic systems and methods

摘要

A diagnostic system for a vehicle is disclosed. A first difference module generates a first difference based on a first pressure measured at a first secondary air injection (SAI) valve and a previous value of the first pressure. A first summer module generates a first accumulated difference based on a sum of values of the first difference generated during a predetermined period. A second difference module generates a second difference based on a second pressure measured at a second SAI valve and a previous value of the second pressure. A second summer module generates a second accumulated difference based on a sum of values of the second difference generated during the predetermined period. A fault indication module selectively indicates that a fault is present downstream of one of the first and second SAI valves based on the first and second accumulated differences.

主权项

1. A diagnostic system for a vehicle, comprising:
a first electronic circuit that generates a first difference based on a first pressure measured at a first secondary air injection (SAI) valve and a previous value of the first pressure; a second electronic circuit that generates a first accumulated difference based on a sum of values of the first difference generated during a predetermined period; a third electronic circuit that generates a first average of the values of the first difference generated during the predetermined period based on the first accumulated difference; a fourth electronic circuit that generates a second difference based on a second pressure measured at a second SAI valve and a previous value of the second pressure; a fifth electronic circuit that generates a second accumulated difference based on a sum of values of the second difference generated during the predetermined period; a sixth electronic circuit that generates a second average of the values of the second difference generated during the predetermined period based on the second accumulated difference; a seventh electronic circuit that selectively indicates that a fault is present downstream of one of the first and second SAI valves based on a difference between the first and second averages; and an eighth electronic circuit that illuminates a malfunction indicator lamp when the seventh electronic circuit indicates that the fault is present.