Soot Estimation Accuracy via Temperature Correction
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Solution Overview
Problem
The existing methods for diagnosing lubricant degradation in internal combustion engines are not accurate enough, as they fail to account for the temperature of the combustion chamber, leading to incorrect estimation of soot formation and subsequent lubricant degradation.
Innovation Solution
A method and apparatus that estimate the amount of soot formed in the combustion chamber based on engine speed and load, with temperature corrections to improve accuracy, using two temperature data maps to interpolate soot amounts and account for varying engine speeds and loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If the amount of soot is estimated based only on engine speed and load parameter, then the estimation method is simple, but the estimation accuracy is insufficient because combustion chamber temperature variations are not accounted for
Solution Approach 1:
The patent applies parameter changes by introducing combustion chamber temperature as an additional parameter to the soot estimation model. The diagnosis apparatus calculates soot amounts using multiple parameters (engine speed, load parameter, and combustion chamber temperature) instead of relying solely on speed and load. This allows the system to account for temperature-dependent soot formation variations, improving estimation accuracy while maintaining computational feasibility through formula-based calculations.
2Reliability
If the combustion chamber temperature is low, then more fuel is injected to ensure vaporization, but this increases the fuel injection period and causes the last stage to overlap with late compression stroke, resulting in increased soot formation
Solution Approach 1:
The patent implements feedback by using the calculated combustion chamber temperature to adjust the soot estimation process. The system continuously monitors temperature conditions and applies temperature-specific correction formulas to the soot calculation. When low temperature conditions are detected, the system automatically applies appropriate correction factors that account for the increased soot formation tendency, creating a closed-loop estimation process that adapts to varying operational conditions.
Data Source
AI summary
An apparatus for diagnosing lubricant degradation includes a soot amount estimator configured to estimate an amount of soot formed in a predetermined period in a combustion chamber of an engine, and diagnoses the degradation of a lubricant based on a cumulative value of the amount of soot estimated. The soot amount estimator calculates the amount of soot based on a speed of the engine and a load parameter related to a load of the engine, and corrects, based on a temperature parameter correlated to the temperature of the combustion chamber, the amount of soot calculated into an increased value if the temperature parameter is lower than a predetermined first temperature.