Nitrogen Oxide Emission Control for Internal Combustion Engines
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current methods for controlling nitrogen oxide emissions from internal combustion engines are inadequate for maintaining average emissions within legal limits across various driving cycles, particularly during extreme use or transient conditions, as they rely on statistical adjustments that may not guarantee compliance with stringent emission standards.
Innovation Solution
A method that iteratively calculates short-term and long-term compliance factors for nitrogen oxide emissions per kilometer traveled, adjusting engine and post-treatment system parameters to ensure that emissions remain below a predetermined threshold by determining the torque, engine speed, and water temperature, and making real-time adjustments to the concentration of nitrogen oxides at the exhaust pipe.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If statistical adjustments based on nominal settings are used for different engine operating points, then the average nitrogen oxide emissions can be controlled within legal limits under standardized cycles, but compliance cannot be guaranteed during extreme use or transient conditions outside the standardized cycle
Solution Approach 1:
The patent implements dynamic adjustment of engine and after-treatment system settings based on real-time monitoring of cumulative nitrogen oxide emissions and distance traveled. Instead of static nominal settings for each operating point, the system continuously adapts parameters such as exhaust gas recirculation rate, fuel injection timing, and after-treatment activation to maintain compliance during any driving cycle, including extreme and transient conditions not covered by standardized test cycles.
Solution Approach 2:
The system incorporates a feedback mechanism that continuously calculates the ratio of cumulative nitrogen oxide emissions to distance traveled and compares it against legal thresholds. Based on this feedback, the control system dynamically adjusts engine operating parameters and after-treatment system activation to ensure compliance. This closed-loop control guarantees emission limits are maintained regardless of the specific driving cycle or operating conditions encountered.
2Object-generated harmful factors
If after-treatment systems with high treatment efficiency are used, then nitrogen oxide emissions can be reduced to meet legal standards, but the system complexity and cost increase
Solution Approach 1:
The patent applies partial action by selectively activating after-treatment systems only when and where needed to achieve compliance. Rather than continuously operating high-efficiency after-treatment systems at all times, the control method monitors emission accumulation and distance traveled, activating after-treatment measures proportionally to maintain the emission-to-distance ratio below legal thresholds. This approach achieves emission reduction goals while minimizing the operational complexity and energy consumption of after-treatment systems.
3Object-generated harmful factors
If engine parameters are adjusted to reduce nitrogen oxide emissions at all operating points, then average emissions decrease, but engine performance and fuel consumption may be adversely affected
Solution Approach 1:
The system performs preliminary action by proactively managing nitrogen oxide accumulation before legal limits are exceeded. It continuously calculates cumulative emissions and distance traveled, allowing the engine to operate at optimal performance settings for extended periods, then activates after-treatment measures or adjusts parameters only when the emission-to-distance ratio approaches regulatory thresholds. This prevents excessive emission reduction at all times, maintaining engine performance while ensuring compliance is achieved through timely, targeted interventions.
Data Source
Figure 1
Figure 2
Figure 3
AI summary
The invention relates to a control method that allows the mean quantity of nitrogen oxides per kilometre covered emitted by a vehicle fitted with an internal combustion engine associated with a post-treatment system to be kept below a predefined fixed threshold, for any journey made by the vehicle. The mean quantity emitted over a fixed elementary distance that has just been covered by the vehicle is calculated iteratively, together with a long-term conformity factor which is equal to the mean quantity emitted over the entire distance covered since the start of the journey. When it is found that the long-term conformity factor is above the threshold, the engine and/or the post-treatment system is regulated in such a way as to obtain, over the next fixed elementary distance, a mean quantity of nitrogen oxides per kilometre that is lower than the threshold value FC, for example equal to 90% of the threshold, whatever the engine operating point. Thus, the long-term conformity factor converges towards the threshold.