Method and apparatus for monitoring catalyst efficiency and secondary air injection

A catalytic converter monitor, comprising:

• a secondary air injector;
• a catalytic converter;
• an inlet sensor that senses a first oxygen level of exhaust gases entering said catalytic converter;
• an outlet sensor that senses a second oxygen level of exhaust gases exiting said catalytic converter;
• a controller that communicates with an engine, said inlet sensor and said outlet sensor, that initiates a rich condition after detecting an engine steady state condition, and that initiates said secondary air injector to inject a secondary air stream into said exhaust stream to simulate a lean opting condition, wherein said controller ceases operation of said secondary air injector when said outlet sensor has detected said lean condition for a predetermined period of time;
• and
• wherein said controller generates a secondary air injector fault if said inlet sensor fails to detect said lean condition.

A method of monitoring a secondary air injector and a catalytic converter, comprising:

• operating an engine in a rich condition after detecting an engine steady state condition;
• initiating said secondary air injector to inject air into an exhaust stream to simulate a lean condition of said engine;
• ceasing injection of said air into said exhaust stream after both an inlet and outlet sensor detect said lean condition;
• determining a lag time between said inlet sensor detecting said rich condition after ceasing injection of said air and said outlet sensor detecting said rich operating condition;
• and
• signaling a secondary air injector fault if said inlet sensor fails to detect said lean condition.