Soot Estimation Using Speed-Load Maps and Deviation Corrections
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Solution Overview
Problem
Current soot emission estimation methods for diesel engines lack accuracy and robustness, failing to account for internal and external processes influencing physical parameters, leading to high calibration efforts and reduced precision.
Innovation Solution
A method that estimates soot emissions by using engine speed and load measurements, along with emission influencing input parameters like exhaust lambda value and intake manifold gas temperature, to calculate deviations and apply corrections, resulting in a more accurate and robust soot mass flow estimation, which optimizes the regeneration control strategy of the diesel particulate filter.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If conventional soot emission estimation methods are used, then the estimation can be performed with basic engine parameters, but the accuracy and robustness are insufficient due to not accounting for emission influencing parameters
Solution Approach 1:
The soot emission estimation is segmented into multiple independent components: a base soot value from speed-load maps and separate correction terms for each emission influencing parameter (intake manifold pressure, temperature, oxygen mass ratio, piston cooling). This segmentation allows each parameter to be handled independently, improving accuracy without creating a monolithic complex system.
Solution Approach 2:
The estimation method uses universal speed-load resolved reference maps and weight maps that can be applied across different operating conditions and engine loads. These maps serve multiple functions: providing base values, calculating deviations, and determining correction weights, making the system versatile without requiring separate complex models for each condition.
2Ease of manufacture
If conventional estimation methods are used, then implementation is simpler, but calibration effort remains high during late stages of engine development
Solution Approach 1:
Speed-load resolved reference maps and weight maps are pre-calculated and stored before actual engine operation. This preliminary action during the development phase captures real soot formation dependencies, allowing the production system to simply retrieve and apply these pre-computed values, significantly reducing calibration time during late development stages.
Solution Approach 2:
The method uses reference maps that capture ideal soot formation characteristics under various conditions. These reference maps serve as templates or copies of optimal behavior that can be directly applied and adjusted via correction terms, eliminating the need to perform extensive calibration experiments during late development.
3Reliability
If conventional estimation methods are used, then the system is less complex, but robustness towards internal and external processes influencing physical parameters is reduced
Solution Approach 1:
The system continuously monitors emission influencing parameters (intake manifold pressure, temperature, oxygen mass ratio, piston cooling status) and uses real-time feedback to calculate deviations from reference values. This feedback mechanism ensures the estimation adapts to changing internal and external conditions, maintaining robustness against process variations.
Solution Approach 2:
The method explicitly accounts for changes in key parameters (intake manifold pressure, temperature, oxygen mass ratio, piston cooling) by calculating their deviations from reference values and applying appropriate corrections. This parameter-based approach makes the system robust to variations in operating conditions and environmental factors.
Data Source
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AI summary
A soot emission estimation method and arrangement for a diesel engine for estimating the amount of soot generated in a combustion chamber of the diesel engine. The method comprises the steps of: providing values for speed and load by measuring the engine speed and the fuel injection amount; providing a base soot value from an engine speed-load resolved reference soot map; defining and providing emission influencing input parameters by measuring corresponding signal values; calculating a deviation between at least one emission influencing input parameter and a speed-load resolved reference value for the at least one emission influencing input parameter; multiplying the calculated deviation with an individual value from an individual speed-load resolved weight map for the at least one emission influencing input parameter, thereby creating an emission influencing input parameter related correction for the at least one emission influencing input parameter; adding and summarizing the at least one emission influencing input parameter related correction to the base soot value and thereby obtaining an estimated soot mass flow value.