Chrysler laser 1990 Technical Information Manual page 133

When exposed to light, the photo diode conducts
by the arrow and dotted line and a voltage (5 volts) is
applied to the comparator of the sensor unit so that
the terminal voltage of the engine control unit
becomes 5 volts. When the disc rotates further and
OXYGEN SENSOR
Cover
air/fuel
Stoichiometric
Air/fuel ratio
FUEL SYSTEM - Sensors
Heater
The oxygen sensor is mounted at the outlet of the exhaust
manifold or the turbocharger. The sensor, which uses an
oxygen concentration cell having a, solid electrolyte, has such
characteristics that its output voltage changes sharply in the
vicinity of the stoichiometric air/fuel ratio.
Lean
The sensor makes use of this characteristic to detect oxygen
concentration in the exhaust gas and feeds back the signal to
the engine control unit, which then decides if the air/fuel ratio is
rich or iean relative to the stoichiometric ratio.
Based on this decision, the air/fuel ratio is feedback-controlled
to achieve the stoichiometric ratio at which the catalytic
converter operates most effectively.
In addition, because this oxygen sensor incorporates a heater,
the response of the sensor is good even if the temperature of
the exhaust gas is low, and, as a result, feedback control of the
air/fuel ratio is possible for a short time after the engine is
started.
the slit moves beyond the space between the
LED/photo diode pair, the light can no longer reach
the photo diode, thus the current indicated by the
dotted line ceases to flow and the terminal voltage
of the engine control unit becomes 0 volt. tn this
way, pulse signals are sent to the engine control
unit from the sensor unit.
Lead wires
Engine
control unit
Connector