Vehicle NOx Margin Control Using Overlapping Moving Averages
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Solution Overview
Problem
Existing methods for calibrating vehicle engines to reduce emissions result in degraded performance across all driving scenarios due to sensitivity to various factors, making it difficult to manage the tradeoff between emissions reduction and performance optimization.
Innovation Solution
An emissions margin controller predicts the margin between actual and threshold NOx emissions using overlapping moving average windows, adjusting engine parameters to maintain performance while ensuring emissions stay within limits, with an early detection system for timely adjustments.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional calibration methods are used to reduce emissions for worst-case scenarios, then emissions are reduced, but vehicle performance is degraded for all drivers in all scenarios
Solution Approach 1:
The system dynamically adjusts engine parameters based on real-time monitoring of moving average NOx emissions and predicted sensitivity factors. Instead of static worst-case calibration, the controller continuously adapts operating parameters (fuel injection timing, EGR rate, valve timing) to maintain emissions compliance while optimizing performance for current driving conditions
Solution Approach 2:
The system changes multiple engine operating parameters simultaneously based on predicted emissions sensitivity. The controller adjusts fuel injection parameters, exhaust gas recirculation rates, and valve timing to reduce NOx emissions only when and where needed, rather than applying uniform conservative settings across all operating conditions
2Object-generated harmful factors
If engine parameters are adjusted to reduce emissions, then emissions are reduced, but vehicle performance is degraded
Solution Approach 1:
The system performs preliminary detection of emissions trends using moving average calculations and early warning algorithms. When emissions are predicted to approach threshold levels, the controller proactively adjusts parameters before actual violations occur, allowing for less severe corrections that minimize performance impact
Solution Approach 2:
The system implements closed-loop feedback by continuously monitoring tailpipe NOx emissions through sensors and comparing actual emissions against predicted values and regulatory thresholds. The controller uses this feedback to make real-time parameter adjustments, ensuring emissions compliance while maintaining optimal performance
3Reliability
If conservative calibration is applied to ensure emissions compliance, then emissions are controlled, but vehicle performance is degraded across all scenarios
Solution Approach 1:
The system segments the emissions control problem by analyzing sensitivity to individual factors (vehicle weight, catalyst state, elevation, driver behavior) separately. The controller determines the dominant sensitivity factor for current conditions and applies targeted parameter adjustments specific to that factor, rather than applying conservative settings for all possible factors simultaneously
Data Source
AI summary
Methods and systems are provided for optimizing a performance of a vehicle while maintaining vehicle emissions below a threshold. In one example, a method for a controller of a vehicle comprises adjusting an operating parameter of the vehicle in response to a margin between a moving average tailpipe NOx emissions and a threshold tailpipe NOx emissions decreasing below a threshold NOx emissions margin, the moving average tailpipe NOx emissions calculated at regular intervals over a plurality of overlapping moving average windows (MAWs) of measured tailpipe NOx emissions. The threshold tailpipe NOx margin may be predicted based on expected engine-out NOx emissions of the vehicle, current NOx emissions sensitivities, and/or a predicted catalyst conversion efficiency in relation to the expected engine-out NOx emissions.