Hyundai Elantra: Exhaust Emission Control System / Description and operation

Hyundai Elantra (CN7) 2021-2025 Service Manual / Emission Control System / Exhaust Emission Control System / Description and operation

Description

Exhaust emissions (CO, HC, NOx) are controlled by a combination of engine modifications and the addition of special control components.

Modifications to the combustion chamber, intake manifold, camshaft and ignition system form the basic control system.

These items have been integrated into a highly effective system which controls exhaust emissions while maintaining good drivability and fuel economy.

Air/Fuel Mixture Control System [Multiport Fuel Injection (MFI) System]

The MFI system uses signals from the heated oxygen sensor to activate and control the injector installed in the manifold for each cylinder, thus precisely regulating the air/fuel mixture ratio and reducing emissions.

This in turn allows the engine to produce exhaust gas of the proper composition to permit the use of a three way catalyst. The three way catalyst is designed to convert the three pollutants [hydrocarbons (HC), carbon monoxide (CO), and oxides of nitrogen (NOx)] into harmless substances. There are two operating modes in the MFI system.

1.	Open Loop air/fuel ratio is controlled by information programmed into the ECM.

2.	Closed Loop air/fuel ratio is adjusted by the ECM based on information supplied by the oxygen sensor.

Exhaust Emission Control System

Catalytic Converter

Description and operation DescriptionThe catalytic converter of the gasoline engine is a three way catalyst. It oxidizes carbon monoxide and hydrocarbons (HC), and separates oxygen from the oxides of nitrogen (NOx)...

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Function malfunction and limitations

Function malfunction

When High Beam Assist is not working properly, the ‘Check High Beam Assist (HBA) system’ or ‘Check HBA (High Beam Assist) system’ warning message will appear and warning light will illuminate on the cluster. Take your vehicle to an authorized HYUNDAI dealer and have the function checked.