SENSORS

Delphi Ammonia Sensor
The Delphi Ammonia Sensor uses a unique Delphi technology to
directly measure ammonia levels in the exhaust of diesel vehicles
equipped with a selective catalytic reduction (SCR) aftertreatment
system. The sensor output can be used to provide feedback to the
SCR system helping provide optimal reduction of NOx emissions.
In a diesel engine SCR system, the ammonia sensor is typically
situated either mid-brick or behind the SCR catalyst. The SCR
system helps reduce NOx emissions in diesel powertrain systems
through a chemical reaction in which ammonia reacts with NOx to
produce nitrogen and water. Ammonia is typically introduced into
the exhaust flow upstream from the SCR in the form of liquid urea.
The ammonia sensor detects excess ammonia in the exhaust gas
allowing for more precise dosing of urea. This added precision
allows for optimal SCR system efficiency and prevents the release
of excess ammonia into the atmosphere.
The Delphi Ammonia Sensor can detect ammonia within a range
of 0 to 100 ppm. If the sensor detects too much ammonia, it
signals the system to reduce the amount of the urea injection. The
planar alumina substrate in the Delphi Ammonia Sensor combines
an integral temperature sensor with a thick-film heater for optimum
performance. The Delphi Ammonia Sensor provides measurement
of ammonia without interference from carbon monoxide and NOx.

Delphi Ammonia Sensor and Ammonia Sensor
Control Module

Benefits
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Provides optimized performance of an SCR converter
Enables the use of an optimally-sized SCR converter
Helps provide SCR system diagnostics
Enables optimal aftertreatment architecture
System includes Delphi-supplied sensor and sensor control module

Typical Applications
The Delphi Ammonia Sensor is intended for use in vehicles equipped with an SCR converter system
including light duty, medium duty and heavy duty diesel vehicles to help manufacturers meet increasingly
stringent NOx emissions regulations.

Availability
The Delphi Ammonia Sensor is in production. Engineering samples are available to current transportation
industry customers upon request. Contact Delphi for further information.

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