Catalytic converter monitor method and apparatus

A catalytic converter monitor apparatus is provided comprising:

• a first temperature sensor mounted in a vehicle exhaust system upstream of a catalytic converter catalyst;
• a second temperature sensor mounted in the vehicle exhaust system downstream of at least a portion of the catalytic converter catalyst;
• an electronic controller coupled to the first and second temperature sensors and to the vehicle engine, wherein the vehicle engine provides an input signal indicative of an engine operating condition to the electronic controller, wherein the electronic controller comprises
• an exotherm monitor for determining a quantity of exothermic reaction taking place in the catalytic converter,
• a table generator responsive to the exotherm monitor for generating a table of exotherm outputs correlating to the engine operating condition, and
• an exotherm analyzer responsive to the exotherm monitor and the table for comparing a present quantity of exothermic reaction to an output stored in the table for the corresponding engine operating condition and for outputting a control signal if the comparison indicates inefficient operation of the catalytic converter.

A catalytic converter monitor apparatus comprising:

• a first temperature sensor mounted in a vehicle exhaust system upstream of a catalytic converter catalyst;
• a second temperature sensor mounted in the vehicle exhaust system downstream of at least a portion of the catalytic converter catalyst;
• an exotherm monitor coupled to the first and second temperature sensors, providing an output signal indicative of a quantity of exothermic reaction taking place in the catalytic converter;
• a table generator coupled to the exotherm monitor, receiving the output signal from the exotherm monitor and generating a table of exotherm criteria responsive to the output signal;
• and
• an exotherm analyzer coupled to the exotherm monitor and the table generator, providing an output responsive to a comparison between a present value of the output signal and a corresponding criteria stored in the table.