PIPE AS-EXHAUST 1131111 - Caterpillar

Clean Emissions Module (CEM)
Illustration 2 g06309582
(1) Exhaust in
(2) DEF injector
(3) Mixers
(4) Diffuser plate
(5) Catalyst brick
(6) Inlet NOx sensor
(7) Pressure sensor
(8) Coolant shunt tank
(9) Exhaust out
(10) Outlet NOx sensor
Illustration 3 g06309620
(2) DEF injector
(6) Inlet NOx sensor
(7) Pressure sensor
(8) Coolant shunt tank
(11) Inlet temperatureThe exhaust gas exits the engine and enters the mixing tube, where the DEF is injected into the exhaust stream.The DEF decomposes into ammonia and carbon dioxide.The mixture of exhaust and ammonia travels through the SCR.The ammonia reacts with the NOx in the exhaust stream at the SCR catalyst to produce water vapor and nitrogen.Pump Electronic Tank Unit (PETU)
Illustration 4 g06309599
(1) DCU
(2) Coolant diverter valve
(3) Back flow valve
(4) Manual fill
(5) DEF pump
(6) Drain plug
(7) DEF header
(8) DEF header heating element
() Ground level fill hose
() Ground level fill valve
Illustration 5 g06311401
(9) Ground level fill valve
(10) Ground level fill hoseCEM Identification Number Module
The identification number module outputs a 10 character alphanumeric serial number for the CEM to the SCR system ECM.The SCR system ECM transmits this data to the engine ECM over the local CAN data link.The engine ECM compares the first 3 letters of the serial number (the prefix) to a value programmed into the engine software.Sensors (CEM)
NOx Sensors
The NOx sensor communicates to the SCR system ECM over the CAN data link. The sensor has built-in diagnostics to indicate sensor failure modes.The SCR system ECM controls the power supply to the NOx sensors.Aftertreatment #1 Intake NOx Sensor
The aftertreatment #1 intake NOx sensor is monitored to control the DEF dosing rate based on engine out emissions levels.Aftertreatment #2 Intake NOx Sensor
The aftertreatment #2 intake NOx sensor is monitored to control the DEF dosing rate based on engine out emissions levels.Aftertreatment #1 Outlet NOx Sensor
The aftertreatment #1 outlet NOx sensor is monitored to control the DEF dosing rate based on catalyst out emissions. The SCR system ECM monitors the sensor to calculate the necessary DEF flow rate to meet emission targets.Aftertreatment #2 Outlet NOx Sensor
The aftertreatment #2 outlet NOx sensor is monitored to control the DEF dosing rate based on catalyst out emissions. The SCR system ECM monitors the sensor to calculate the necessary DEF flow rate to meet emission targets.Temperature Sensors
Aftertreatment #1 SCR Catalyst Intake Gas Temperature Sensor
The aftertreatment #1 SCR catalyst intake gas temperature sensor is monitored for dosing control and system protection.The temperature indicates the capability of the SCR system ECM to calculate the DEF dosing rates. The temperature is monitored to indicate temperatures that are too low or too high.Aftertreatment #2 SCR Catalyst Intake Gas Temperature Sensor
The aftertreatment #2 SCR catalyst intake gas temperature sensor is monitored for dosing control and system protection.The temperature indicates the capability of the SCR system ECM to calculate the DEF dosing rates. The temperature is monitored to indicate temperatures that are too low or too high.Aftertreament #1 Inlet Pressure
The Aftertreatment system ECM monitors the sensor for system protection. The pressure is monitored to indicate pressures that are too low or too high.The pressure is measured at the inlet to the CEM. A pressure that