METHOD AND APPARATUS FOR MONITORING CONTENT OF POISONOUS SUBSTANCE OF EXHAUST GAS FOR INTERNAL COMBUSTION ENGINE

摘要

PURPOSE: To effectively monitor the harzardous substance content of the exhaust gas of an internal combustion engine by finding the enthalpy of the engine from the thermal enthalpy which is generated by the afterburning of the exhaust gas and obtained from the measurements of an electrochemical sensor and the total enthalpy of combustion obtained by calculation. CONSTITUTION: A partial stream of an unprocessed exhaust gas from an internal combustion engine is introduced to a heating device 13 from an exhaust gas pipe 11 through the catalyst of a burning reaction accelerating device 12 and the unburnt part of the unprocessed exhaust gas is oxidized through afterburning by means of a heating regulator 14 provided with a temperature sensor 15. The oxygen content of the oxidized gas is detected by means of an electrochemical sensor 17. Because of the afterburning, an additional actual heating value is generated in the catalyst and the heating power is reduced by a fixed value, and then, the enthalpy HR of combustion is obtained. The signal of the actual heating value is sent to a calculating device 21 from the regulator 14 and the total enthalpy HG of combustion is obtained from the calculated value of the device 21. Then the entropy H of the engine is found from the comparison between the enthalpies HR and HG and a scale for the burning quality of the engine with respect to the air/fuel ratio is obtained.