Three-way catalytic converter, structure |
1 | Ceramic monolith |
2 | Holding mat |
3 | Housing (insulation) |
4 | Substrate coating (washcoat) with components containing rare metals |
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Schematic display of lambda window and three-way catalytic converter |
A | Exhaust not cleaned |
B | Exhaust cleaned |
F | Rich mixture |
M | Lean mixture |
λ | Oxygen (fuel-air ratio) |
CO | Carbon monoxide |
CO2 | Carbon dioxide |
HC | Hydrocarbon |
H2O | Water |
N2 | Nitrogen |
NOX | Nitrogen oxides |
P49.10-2420-76
Overview
This document contains information on:
General
Function
General
The three-way catalytic converter is a vehicle catalytic converter with closed loop for exhaust gas aftertreatment in vehicles with spark-ignition engine. It converts carbon monoxide (CO), nitrogen oxide (NOx) and unburnt hydrocarbons (HC) into carbon dioxide (CO2), nitrogen (N2) and water (H2O).
Function
To be able to effectively remove the pollutants that arise during the combustion process from the exhaust flow, the controlled three-way catalytic converter is used as standard in vehicles with spark-ignition engine.
To ensure a high conversion rate of the pollutants, a closed-loop control circuit keeps the fuel/air ratio (λ) in a narrow range around λ = 1 (lambda window) by means of lambda sensors. The controlled three-way catalytic converter coverts over 99% of the pollutants into harmless constituents and thus significantly reduces the emissions.
The controlled three-way catalytic converter is able to convert nitrogen oxide into nitrogen and oxygen via reduction and carbon monoxide into carbon dioxide and hydrocarbons into water and carbon dioxide via oxidation.