HOUSING 5T7127 - Caterpillar

To meet current emissions legislation requirements, a small amount of certain chemical compounds that are emitted by the engine must not be allowed to enter the atmosphere. The Clean Emissions Module (CEM) that is installed to the engine is designed to convert these chemical compounds into less harmful compounds.
Illustration 1 g02162626
Typical example (1) Diesel Oxidation Catalyst (DOC) (2) Securing clamp (3) Torca clamp (4) Diesel Particulate Filter (DPF) (5) Securing clamp (6) Torca clamp (7) Lifting eye (8) Air inlet for Aftertreatment Regeneration Device (ARD) (9) Connections for coolant manifold (10) Lifting eye
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Typical example (11) Outlet to exhaust system (12) Aftertreatment Regeneration Device (ARD) (13) Lifting eye (14) Exhaust Inlet (15) Mounting cradleThe Engine Aftertreatment System for the engine consists of the following components.
Aftertreatment Regeneration Device (ARD)
Diesel Oxidation Catalyst (DOC)
Diesel Particulate Filter (DPF)The Diesel Oxidation Catalyst (DOC) oxidizes the carbon monoxide and the hydrocarbons that are not burnt in the exhaust gas into carbon dioxide and water. This is a through flow device that will continue to operate during all normal engine operating conditions.The Diesel Particulate Filter (DPF) collects all solid particulate matter in the exhaust gas.The Aftertreatment Regeneration Device (ARD) increases the exhaust gas temperature to a sufficient level. The soot that is collected in the DPF is oxidized to carbon dioxide.A flexible exhaust pipe connects the engine to the Clean Emissions Module (CEM). Refer to Disassembly and Assembly for the correct procedure to install the flexible exhaust pipe.The solid particulate matter that is collected by the DPF consists of soot (carbon) from incomplete combustion of the fuel and inorganic ash from the combustion of any oil in the cylinder.The rate of accumulation of ash is slow. The filter is designed to contain all the ash that is produced until the defined service interval.The soot that is collected must be removed at regular intervals. Removal of the soot is achieved by elevating the exhaust gas temperature by burning fuel in the ARD for a short time period. If the exhaust gas temperature is high enough, the ARD oxidizes the soot into carbon dioxide, which then passes through the filter and into the atmosphere. The ARD may automatically switch ON and OFF. The ARD may be manually controlled by the operator. The ARD is controlled by the sensor for the soot level. The sensor for the level of soot will ensure that the level of soot in the filter is kept within limits. This is referred to as a regeneration of the filter.In order to regenerate the DPF at the right time, the engine ECM must know how much soot is in the DPF. Measurement of soot is accomplished through the following means:
Delta pressure measurement across the DPF
Radio frequency measurement across the DPF
Calculated model based on developed engine out soot measurementsThe information gathered from these three inputs is then converted into a percentage of soot output that is viewable through electronic soot level gauges. These gauges can be found in the cab of most applications as well as