Catalytic converter monitor

Claim 1

Thermal response apparatus for monitoring the activity of a catalytic converter that includes a housing, a catalytic element disposed within said housing, an inlet for directing exhaust gases into said housing and thrOugh said catalytic element wherein the gases are treated, and an outlet for directing the treated gases out of said housing, said thermal responsive apparatus comprising, first and second opposed chambers, flexible diaphragm means sealingly separating said opposed chambers into two substantially equal chambers, said diaphragm being movable in response to a differential fluid pressure between said chambers, a first closed end tube communicating with said first chamber and having a portion thereof disposed within and along the length of said catalytic element and arranged so as to be responsive to an average of the temperatures of exhaust gases directed through the length of said catalytic element, a second closed end tube communicating with said second chamber and having a portion thereof disposed in said outlet and arranged so as to be responsive to the temperature of the gases passing through said outlet, said chambers and said tubes being filled with a thermally expansible fluid, a grounded contact mounted on said flexible diaphragm means, an adjustable contact means opposite said grounded contact that is adapted to contact said grounded contact when the fluid pressure differential between said second chamber and said first chamber is below a predetermined fluid pressure differential to close a circuit, and being further adapted to move away from said grounded contact to open the circuit when said fluid pressure differential in said second chamber is greater than in said first chamber, to thereby open the circuit, and an indicator lamp in said circuit adapted to be operative when said circuit is closed indicating that said element is operating below a predetermined level of activity and further adapted to be inoperative when said circuit is open.