Catalyst Heating Control via NOx Sensor Feedback
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Solution Overview
Problem
Current methods for heating catalysts in internal combustion engines to reduce NOx emissions after a cold start are inefficient, leading to increased fuel consumption and inability to precisely optimize heating time due to variability in engine parameters, with existing technologies either causing fuel overconsumption or failing to accurately determine when the catalyst has reached its priming temperature.
Innovation Solution
A method that utilizes a nitrogen oxide concentration sensor to measure the concentration of NOx emissions at the catalyst outlet, determining a specific parameter representative of the NOx quantity, and stopping the catalyst heating once this parameter reaches a predetermined threshold, ensuring the catalyst is only heated until it reaches its priming temperature, thereby optimizing heating time and reducing unnecessary fuel consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the ignition advance is significantly reduced to heat the catalyst quickly, then the catalyst reaches operating temperature faster, but fuel consumption increases by approximately 30%
Solution Approach 1:
The system uses a nitrogen oxide concentration sensor to provide feedback on catalyst performance. By monitoring NOx concentration at the catalyst outlet, the control system can determine when the catalyst has reached sufficient temperature and activity to effectively reduce emissions, thereby optimizing the heating duration and reducing unnecessary fuel consumption.
Solution Approach 2:
The patent replaces direct mechanical/thermal monitoring of catalyst temperature with a chemical sensing approach. Instead of measuring temperature directly (which would require additional sensors and complex calibration), the system substitutes temperature measurement with NOx concentration measurement, which indirectly indicates catalyst state and eliminates the need for direct thermal feedback.
2Reliability
If the catalyst heating time is calibrated to the worst case to ensure adequate emissions treatment, then emissions compliance is guaranteed, but fuel consumption increases in less severe cases
Solution Approach 1:
The nitrogen oxide concentration sensor provides real-time feedback on actual catalyst performance. This allows the control system to adaptively adjust heating duration based on actual emissions reduction effectiveness rather than relying on fixed worst-case calibration, thereby maintaining reliability while reducing energy consumption in milder operating conditions.
Solution Approach 2:
The system transitions from static, pre-calibrated heating strategies to dynamic, adaptive control. By continuously monitoring NOx concentration and adjusting heating duration in real-time based on actual catalyst performance, the system optimizes the balance between emissions treatment reliability and fuel consumption across varying operating conditions.
3Reliability
If electrical heating or air injection is used to heat the catalyst, then the catalyst reaches operating temperature more reliably, but fuel consumption increases due to the energy required for these auxiliary systems
Solution Approach 1:
The nitrogen oxide concentration sensor provides feedback that enables precise determination of when catalyst heating is sufficient. This feedback mechanism allows the system to use only the necessary amount of auxiliary heating (electrical or air injection) to reach the required catalyst activity level, avoiding excessive energy consumption while maintaining reliable emissions treatment.
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 allows for precise control of catalyst heating, preventing unnecessary heating and reducing fuel consumption by using existing vehicle sensors to determine when the catalyst has reached its operational temperature, thus enhancing emissions treatment efficiency while adhering to stricter emission standards.
Implementation Method 1
a step of measuring the concentration of nitrogen oxides by the sensor at the outlet of the catalyst
Implementation Method 2
due to internal exothermic reactions
Data Source
Figure 1~2a
Figure 2b
AI summary
The invention relates to a method for optimizing the heating of a catalyst (16) after a cold start of a vehicle comprising an internal combustion engine (2), said vehicle having an exhaust system (4) equipped with a catalyst (16) and a nitrogen oxide concentration sensor (18) at the outlet of said catalyst (16). According to the invention, said method comprises the following steps: - a step of heating the catalyst (16), - a step of measuring the nitrogen oxide concentration by the sensor (18) at the outlet of the catalyst (16) as soon as said vehicle starts, - a step of determining a specific parameter which is a function of the measurement by the sensor (18), - a step of stopping the heating of the catalyst (16) as soon as said parameter has reached a predetermined threshold value.