Cylinder-Specific Lambda Controller Diagnosis for Engine Emissions
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Solution Overview
Problem
Internal combustion engines face challenges in maintaining a precise air/fuel ratio across cylinders due to stringent emission regulations, leading to uneven distribution and increased emissions, which traditional cylinder-specific lambda control methods struggle to address effectively.
Innovation Solution
A method and device that utilize a lambda controller with a modified proportional jump and reduced integral parameter to perform cylinder-specific diagnosis during a detection phase, adjusting the air/fuel mixture to achieve a leaner condition and determine diagnostic values, while operating in a lower partial load mode to minimize disruptions and ensure efficient emissions control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-generated harmful factors
If traditional cylinder-specific lambda control is used, then emissions control is attempted, but uneven air/fuel ratio distribution between cylinders persists and emissions remain high
Solution Approach 1:
The patent divides the control system into cylinder-specific segments, with individual lambda values determined for each cylinder based on its unsmooth running characteristics. This segmentation allows precise control of air/fuel ratio in each cylinder rather than uniform control across all cylinders, directly addressing the uneven distribution problem.
Solution Approach 2:
The patent applies local quality by assigning different lambda values to different cylinders based on their individual unsmooth running values. Each cylinder receives a customized air/fuel ratio setting tailored to its specific combustion characteristics, enabling precise local optimization of emissions control.
2Object-generated harmful factors
If cylinder-specific diagnosis is performed continuously, then precise emissions control is achieved, but engine operation disruptions increase
Solution Approach 1:
The patent implements periodic action by performing cylinder-specific diagnosis only during predefined detection phases rather than continuously. The lambda controller alternates between normal operation mode and detection phase mode, conducting unsmooth running determinations only during specific periodic intervals, thus minimizing disruptions to engine operation while maintaining emissions control precision.
3Speed
If integral parameter of lambda controller is high, then air/fuel ratio control responsiveness is improved, but diagnosis quality during detection phase deteriorates
Solution Approach 1:
The patent applies dynamics by making the integral parameter of the lambda controller time-dependent and mode-dependent. The integral parameter is adapted based on the current operating mode (normal operation vs. detection phase), allowing the controller to optimize between responsiveness and diagnosis quality dynamically rather than using a fixed parameter value.
Solution Approach 2:
The patent implements parameter changes by modifying the integral parameter value according to the operational phase. During detection phases, the integral parameter is adjusted to prioritize diagnosis accuracy, while during normal operation, it is set to maximize air/fuel ratio control responsiveness, thus resolving the contradiction between the two requirements.
Data Source
AI summary
An internal combustion engine has a plurality of cylinders with fuel-metering injection valves, and an exhaust gas probe that generates a measurement signal characteristic of the air/fuel ratio in the respective cylinder. A correction signal for fuel mass to be metered is determined using a lambda controller as a function of the exhaust gas probe measurement signal. When at least one predefined condition is met within a predefined operating range of the engine, a cylinder-specific diagnosis relating to the emissions of pollutants is performed on the basis of unsmooth running, wherein the cylinder-specific diagnosis is actively performed only in a respective detection phase that is applied to a neutral value by a modified proportional discrete level of the correction signal and is performed with a modified integral parameter of the lambda controller that is reduced as compared with an integral parameter in a normal operating mode of the lambda controller.