Page 82 - Methods For Monitoring And Diagnosing The Efficiency Of Catalytic Converters A Patent - oriented Survey

64 Methods for Monitoring and Diagnosing the Efficiency of Catalytic Converters

a predetermined low voltage when exhaust gases are lean of stoichiometry. Both compared
and non-compared signals are coupled to the controller.

Another conventional exhaust gas oxygen sensor 2 is shown coupled to the exhaust manifold
downstream of the catalytic converter and provides signal VZ to the controller which is related
to oxygen content in the exhaust gases. Output signal VZ is also compared to a reference
value associated with stoichiometry in the comparator for providing two-state output signal
V2 to the controller. The two-state output signal Vz is preselected high voltage when exhaust
gases downstream of the catalytic converter are rich of stoichiometry and a low preselected
voltage when such exhaust gases are lean of stoichiometry.
The intake manifold of the engine is shown coupled to a throttle body having primary throttle
plate positioned therein. The throttle body is also shown having a fuel injector coupled
thereto for delivering liquid fie1 in proportion to the pulse width of a signal from the
controller. Fuel is delivered to the fuel injector by a conventional fuel system including fuel
tank, fuel pump, and fuel rail.

n

Fig. 29 (tiom EP06 19420)