Onboard Emissions Monitoring With Cascaded Moving Average Windows
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Solution Overview
Problem
Existing methods for onboard emissions monitoring in commercial vehicles are inefficient and do not optimally utilize computing power, particularly in real-time compliance with moving average window procedures for NOx, NH3, and particulate matter, which are crucial for adhering to environmental regulations.
Innovation Solution
A method utilizing cascaded accumulators to accumulate work-based emission values, calculating moving averages and percentiles, and employing a dynamic window start to optimize computing power and ensure compliance with emission control laws, implemented in an electronic control unit.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If a single accumulator is used to accumulate emission values until reference work is reached, then the monitoring process is simple, but computing power is not optimized and efficiency is reduced
Solution Approach 1:
The single accumulator is divided into multiple accumulators (first accumulator, second accumulator, third accumulator, etc.) that process emission values in segments. Each accumulator handles a portion of the reference work accumulation, allowing parallel processing and optimized computing power utilization while maintaining the overall monitoring function.
2Measurement precision
If emission values are accumulated continuously without categorization, then the process is straightforward, but precision in determining percentiles is reduced
Solution Approach 1:
Emission values are categorized into different ranges (first range, second range, third range, etc.) with each range having associated frequency counts. This local categorization allows for more precise percentile determination by analyzing the distribution of values within specific ranges rather than treating all values uniformly.
3Adaptability or versatility
If fixed time intervals are used for accumulation windows, then the implementation is simple, but adaptability to varying work rates is reduced
Solution Approach 1:
The accumulation windows are made dynamic by using work-based triggers instead of fixed time intervals. The system automatically adjusts the accumulation period based on the work performed, with windows starting and ending based on reference work thresholds. This allows the monitoring system to adapt to varying work rates and operational conditions while maintaining consistent measurement intervals relative to work output.
Data Source
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AI summary
The invention relates to a method for onboard monitoring of emissions in a commercial vehicle, wherein the method is implemented in an electronic control unit of the commercial vehicle, wherein a calculation of a moving average of an emission species is performed, wherein a plurality N of accumulators (ΣNOX) are used to accumulate emission values from an input vector (NOXtp, NH3tp) detected during the journey of the commercial vehicle, wherein a first accumulator (ΣNOX) accumulates the emission values of the input vector (NOXtp, NH3tp) from the beginning of a journey until the work (W) performed by the commercial vehicle since the beginning of this accumulation corresponds to a predetermined reference work (W_ref), wherein after each Nth of the reference work (W_ref) a further accumulator (ΣNOX) accumulates the emission values of the input vector (NOXtp, NH3tp).until the work (W) performed by the commercial vehicle since the start of this accumulation corresponds to the specified reference work (W_ref), wherein the emission values (NOX MAW) accumulated by the accumulators (ΣNOX) are categorized into a vector (V) which has a number of elements with emission value ranges (EWB) with associated emission value frequencies (EWH), wherein a sorting process is applied to the vector (V) to determine the hundredth and ninetieth percentiles (P90, P100) for each trip.