Exhaust Gas Cleaning, Basic Function - GF49.00-P-1000A

WARNING: This page is about a different car, the 2023 Mercedes-Benz GLC300, 2022 Mercedes-Benz GLC300, 2021 Mercedes-Benz GLC300, 2020 Mercedes-Benz GLC350e, and 2020 Mercedes-Benz GLC300. However, it is still accessible from the selected car via links, so may be relevant.

Engine all (4xWD)

Engine all (CAR)

Overview

This document contains information on:

General
Function requirements
Function

General

Exhaust gas cleaning fulfills a central task of the exhaust gas aftertreatment. Exhaust gas cleaning ensures the targeted reduction of exhaust gas emissions.

Function requirements

Engine management ON (circuit 87M)
Engine in operation
Catalytic converters at operating temperature (approx. 300°C)
Stoichiometric fuel/air ratio in the exhaust gas
Coolant temperature and exhaust gas temperature reached for gasoline particulate filter regeneration phase

Function

The following exhaust gases that are hazardous to health and the environment are generated during fuel combustion, for example:

Nitrogen oxides (NO_x )
Hydrocarbon (HC)
Carbon monoxide (CO)

Catalytic converters are used for exhaust gas cleaning. The requirement for efficient exhaust gas cleaning is a defined mixture formation, which ensures a stoichiometric fuel/air ratio in the exhaust gas for cleaning. The optimum effect of the catalytic converter is ensured in this area.

A mixing ratio of 14.7 kg of air to 1 kg of fuel is necessary in order to achieve theoretically complete combustion. The ratio of air to fuel is a "stoichiometric ratio" (lambda A). If the air volume delivered corresponds to the theoretical air requirement, this results in the value A = 1.

In diesel Engines in particular, but also in spark-ignition Engines, there are also exhaust gas emissions in the form of soot particles. A gasoline particulate filter is used for cleaning here.

The following catalytic converters and gasoline particulate filters are used for exhaust gas cleaning:

Diesel Engine	Spark-ignition Engine
Oxidation catalytic converter: Vehicle catalytic converter for converting the pollutants of carbon monoxide and hydrocarbons, which are generated during fuel combustion, into carbon dioxide (CO₂ ) and water (H₂ O). As it is an upstream component, it also contributes to removing NOx from the exhaust gases. To do so, it converts nitric oxide (NO) to nitrogen dioxide (NO).	Three-way catalytic converter: Vehicle catalytic converter with lambda control for exhaust gas aftertreatment in vehicles with a spark-ignition Engine. Carbon monoxide, nitrogen oxide and unburned hydrocarbons are converted into carbon dioxide (CO2), nitrogen (N₂ ) and water (H₂ O).
SCR catalytic converter: Vehicle catalytic converter for reducing nitrogen oxide emissions using ammonia (NH3). Ammonia is generated with the aid of a reduction agent. The nitrogen oxide in the exhaust gas reacts with ammonia and oxygen to form molecular nitrogen (N2) and water vapor.	Gasoline particulate filter: Filter unit that filters and stores soot particles that are generated during the combustion process. It also ensures soot particle oxidization during gasoline particulate filter regeneration.
Gasoline particulate filter: Filter unit that filters and stores soot particles that are generated during the combustion process. It also ensures soot particle combustion during the regeneration of the gasoline particulate filter.

Depending on the fuel type, injection procedure, combustion temperature and pressure, different concentrations of nitrogen oxide are generated in the exhaust gas during the combustion of the fuel/air mixture. Different types or combinations of catalytic converters are used in order to ensure compliance with the emissions limit value required by law.

Function schematics
Function schematic for exhaust gas cleaning	Engine 608 in model 118, 177, 247 Engine 654 in model 118, 167, 177, 247 Engine 656 in model 167	PE49.00-P-2500-97A
	Engine 654 in model 118, 177, 247 Engine 654, 656 in model 167	PE49.00-P-2500-97B
	Engine 176, 177 in model 167 Engine 177.8 in model 290	PE49.00-P-2500-97C
	Engine 139 in model 118, 177, 247	PE49.00-P-2500-97D
	Engine 177.8 in model 223, 232	PE49.00-P-2500-97E
	Engine 254 in model 206 Engine 254 in model 254 Engine 256 in model 223	PE49.00-P-2500-97F
	Engine 139 in model 206, 232	PE49.00-P-2500-97G
	Engine 654 in model 206, 254 Engine 656 in model 223	PE49.00-P-2500-97H
	Engine 279 in model 223	PE49.00-P-2500-97I
	Engine 176 in model 223	PE49.00-P-2500-97J
	Engine 274 in model 213 as of model year 2021	PE49.00-P-2500-97K
	Engine 656 in model 464	PE49.00-P-2500-97L
Additional basic functions
Catalytic process, basic function		GF49.20-P-1004A
Control units
Soot particulate sensor control unit, basic function	Engine 608 in model 118, 177, 247 with code 460 (Canada version) with code 494 (US version)	GF49.20-P-9893A
	Engine 654 in model 118, 167, 177, 206, 247, 254 with code 460 (Canada version) with code 494 (US version) Engine 654 in model 213, 238, 257 as of model year 2021 with code 460 (Canada version) with code 494 (US version) Engine 656 in model 167, 223 with code 460 (Canada version) with code 494 (US version) Engine 656 in model 213, 238, 257 as of model year 2021 with code 460 (Canada version) with code 494 (US version)
Components
Soot particulate filter, basic function	Engine 608 in model 118, 177, 247 with code 460 (Canada version) with code 494 (US version)	GF49.20-P-1007A
	Engine 654 in model 118, 177, 206, 247, 254 with code 460 (Canada version) with code 494 (US version) Engine 654 in model 213, 238, 257 as of model year 2021 with code 460 (Canada version) with code 494 (US version) Engine 656 in model 167, 223 with code 460 (Canada version) with code 494 (US version) Engine 656 in model 213, 238, 257 as of model year 2021 with code 460 (Canada version) with code 494 (US version)