Fuel Dilution Estimation in Engine Oil Using Kinetic Evaporation

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Solution Overview

Problem

Existing methods for estimating fuel dilution in engine oil lack precision, particularly during the decrease in dilution between regeneration phases, leading to potential engine reliability risks and increased maintenance costs due to inaccurate evaporation rate calculations.

Innovation Solution

A method that calculates the variation in fuel evaporation between two instants using a kinetic law of order 1, considering the time elapsed since the last regeneration, along with evaporation temperature and enthalpy, to accurately estimate dilution rates.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Device complexity

If existing methods use simplified evaporation models that do not account for time elapsed since last regeneration, then the device complexity is reduced, but the measurement precision of dilution estimation deteriorates

Engineering Contradiction:
Improvecomplexity of evaporation modelVSAvoidprecision of dilution estimation
Core Design Contradiction:
Device complexityVSMeasurement precision

Solution Approach 1:

The evaporation model is made dynamic by incorporating the time elapsed since the last regeneration phase as a variable parameter. The evaporation rate is not fixed but changes over time according to the kinetic law of order 1, adapting to the progressive change in fuel composition as light hydrocarbons evaporate first and heavy compounds remain

Inventive Principle:
Principle #15Dynamics

Solution Approach 2:

The model changes the evaporation rate parameter based on the time elapsed since last regeneration. As time progresses, the composition of diluted fuel changes (light hydrocarbons evaporate first), and the model adjusts the evaporation rate accordingly using the kinetic law equation, rather than using a constant simplified rate

Inventive Principle:
Principle #35Parameter changes

2Reliability

If existing methods underestimate the dilution between regeneration phases, then the reliability of the estimation is improved, but the loss of time for unnecessary oil changes increases

Engineering Contradiction:
Improvereliability of dilution estimationVSAvoidtime for unnecessary oil changes
Core Design Contradiction:
ReliabilityVSLoss of time

Solution Approach 1:

The model uses feedback from the time elapsed since last regeneration to continuously adjust the evaporation rate estimation. This feedback mechanism allows the system to account for the changing fuel composition over time, providing more accurate dilution estimates that prevent both premature and delayed oil change decisions

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The model performs preliminary calculation of the evaporation rate based on the kinetic law before determining the actual dilution level. By预先 establishing the time-dependent evaporation rate, the system can more accurately predict when the dilution threshold will be reached, avoiding unnecessary early oil changes

Inventive Principle:
Principle #10Preliminary action

Applied Scientific Principles

This section explains which scientific principles are used to turn an abstract innovation direction into a practical engineering solution.

Function Achieved in This Case

This approach provides a more precise estimation of fuel dilution, enabling timely oil changes and reducing the risk of engine reliability issues and unnecessary maintenance costs.

Implementation Method 1

the dilution drops under the effect of the evaporation of part of the fuel diluted since the end of the last regeneration which took place

Methodology Applied
Scientific EffectEvaporation: Evaporation

Data Source

PatentEP2520785B1Method for estimating the dilution of fuel in the oil of an internal combustion engine
Publication Date: 2018.07.25 RENAULT SA
  • EP2520785B1 patent drawingFigure 1
  • EP2520785B1 patent drawingFigure 2~3
  • EP2520785B1 patent drawing

AI summary

The method involves estimating dilution rate (C) of fuel based on an operating mode of an internal combustion engine. Dilution rate variation (dC) is calculated (120) at every instant from a set of parameters apart from a post-injection fuel regeneration phase, where the parameters include a value representative of evaporation temperature of diluted fuel in an oil of the engine and time elapsed from an end of the regeneration phase. The variation of dilution rate during each time step is calculated according to a kinetic law of order 1 by a specific equation.