PURPOSE: To properly perform monitoring the operation of a catalyst converter by measuring the incoming temp. to the catalyst converter and the outlet temp. of exhaust gas going out of the converter, and subjecting the obtained difference to a processing which uses a converting function having an integral term.
CONSTITUTION: The upstream temp. Tus of the exhaust gas inflowing to a catalyst converter 1 is measured by a temp. sensor 3 while the downstream temp. Tds of the exhaust gas outgoing from the converter 1 is measured by another temp. sensor 4, and the obtained sensor outputs are fed to a subtractor 5 to form a differential temp. signal. This differential temp. signal is fed to the first input of a multiplier 6 and multiplied by a signal to represent the mass flow rate dM/dt of the exhaust gas at the second input, and the output signal given is integrated with time by an integrator 7. The resultant integral output signal of the difference in the heat flow rate is compared by a comparator 10 with a certain threshold level, and an indicator 12 is actuated on the basis of the result from comparison.
RATSUSERU UIRUSON JIYOONZU
DEIBUITSUDO UIRIAMUZU
