Ozone Injection with MnO2 and LNT Catalysts for Cold Start Emissions
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Solution Overview
Problem
Existing emission control systems for vehicle exhausts are ineffective in reducing residual pollutants like NO, CO, and hydrocarbons during the cold start phase due to limited catalyst activity at low temperatures.
Innovation Solution
Incorporating an ozone generation system, MnO2 catalyst, and lean NOx trap (LNT) catalyst in the cold part of the exhaust line to oxidize residual pollutants at temperatures between 20° C. and 150° C., with ozone injection and subsequent conversion by the MnO2 and LNT catalysts to reduce NO, CO, and hydrocarbon emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If conventional catalysts are used in the cold start phase, then the system structure remains simple, but pollutant conversion efficiency is insufficient at low temperatures
Solution Approach 1:
Ozone is injected into the exhaust stream before it reaches the catalyst, pre-oxidizing pollutants like CO and hydrocarbons at low temperatures. This preliminary oxidation action enables the catalyst to work effectively even during cold start when temperatures are below its optimal operating range, thereby improving pollutant conversion efficiency without requiring complex heating systems
Solution Approach 2:
The invention changes the chemical parameter of the exhaust gas by introducing ozone, which has strong oxidizing properties. This parameter change (adding ozone) enables pollutant oxidation to occur at lower temperatures, allowing the catalyst to achieve high conversion efficiency during cold start without requiring temperature parameter changes through heating
2Productivity
If catalyst heating is applied during cold start, then pollutant conversion is improved, but energy consumption increases
Solution Approach 1:
Ozone, a strong oxidant, is injected into the exhaust stream to accelerate the oxidation of pollutants like CO and hydrocarbons. This chemical acceleration allows oxidation reactions to proceed efficiently at low temperatures without requiring thermal energy input, thereby improving pollutant conversion while avoiding the energy consumption associated with catalyst heating
3Temperature
If ozone injection is implemented, then low temperature pollutant oxidation is achieved, but system complexity increases
Solution Approach 1:
Ozone acts as an intermediary substance that facilitates pollutant oxidation at low temperatures. By introducing this intermediary oxidant, the system achieves effective pollutant conversion across a broader temperature range including cold start conditions, without requiring complex thermal management systems or modifying the catalyst itself
Applied Scientific Principles
This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.
Function Achieved in This Case
This approach effectively oxidizes residual pollutants, achieving NO2 concentrations below 0.1 mg/km in tailpipe emissions, even at low temperatures, thereby improving cold start emissions control without the need for catalyst heating.
Implementation Method 1
the residuals pollutants may be oxidized at temperatures of from about 20° C. to about 150° C.
Implementation Method 2
converting the first mixture using an MnO2 catalyst to form a second mixture; and converting the second mixture using an LNT catalyst
Data Source
AI summary
Systems for reducing the content of residual pollutants from tailpipes emissions in an exhaust line having a cold part may include an ozone generation system; an MnO2 catalyst; and a lean NOx trap (LNT) catalyst. In these systems, the ozone, MnO2 catalyst, and LNT catalyst may be provided in the cold part of the exhaust line. In these systems, the residuals pollutants may be oxidized at temperatures of from about 20° C. to about 150° C. in rich or lean conditions and NO2 may have a concentration of less than 0.1 mg/km in the tailpipe emissions downstream of the cold part of the exhaust line. Corresponding methods may include generating ozone from an ozonizer; injecting the ozone in a mixing chamber comprising the residual pollutants to form a first mixture; converting the first mixture using an MnO2 catalyst to form a second mixture; and converting the second mixture using an LNT catalyst.