Engine Oil Viscosity Estimation via Fuel Dilution and Evaporation Rates
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Solution Overview
Problem
Current methods for estimating engine oil viscosity in Internal Combustion Engines are inaccurate due to their failure to consider variable oil dilution and hydrocarbon evaporation rates, especially after particulate filter regeneration events, leading to potential engine damage and unnecessary oil changes.
Innovation Solution
A method that calculates oil viscosity by determining the oil dilution rate during particulate filter regeneration and hydrocarbon evaporation rate, taking into account different mission profiles and adjusting setpoints for evaporation time and dilution rates, allowing for real-time estimation and reducing the risk of engine damage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If current methods use constant oil dilution rate and constant HC evaporation rate, then the estimation method is simple, but the measurement precision of oil viscosity is insufficient
Solution Approach 1:
The patent applies dynamics by transitioning from constant rates to variable rates that change with engine operating conditions. The oil dilution rate and HC evaporation rate are dynamically adjusted based on engine speed, temperature, and load, allowing accurate viscosity estimation across different operating points without requiring complex hardware
Solution Approach 2:
The patent changes the parameters of oil dilution rate and HC evaporation rate from fixed values to variable values that depend on engine operating conditions. By introducing multiple parameters (engine speed, temperature, load) that influence these rates, the method achieves higher measurement precision while maintaining computational simplicity
2Reliability
If post injections are used for particulate filter regeneration, then the filter regeneration is achieved, but the oil viscosity decreases due to fuel adsorption
Solution Approach 1:
The patent implements feedback by continuously monitoring engine operating conditions and adjusting the oil viscosity estimation based on actual post-injection events. The system tracks the number of regeneration events and uses this feedback to dynamically modify the evaporation rate parameter, accurately reflecting the impact of fuel adsorption on oil viscosity
Solution Approach 2:
The patent applies preliminary action by anticipating the viscosity decrease before it occurs. By detecting post-injection events and pre-adjusting the estimation parameters, the system prepares the viscosity calculation to account for upcoming fuel adsorption effects, maintaining accuracy throughout the regeneration process
3Measurement precision
If fuel hydrocarbons evaporate from oil during normal operation, then the oil viscosity increases, but the evaporation rate is limited by saturation
Solution Approach 1:
The patent changes the evaporation rate parameter dynamically based on engine operating conditions and the number of previous regeneration events. By introducing a saturation limit that increases with each regeneration event, the model accurately captures the evolving evaporation behavior without requiring complex physical models
Solution Approach 2:
The patent applies dynamics by making the evaporation rate time-dependent and condition-dependent. The rate varies with engine speed, temperature, load, and the cumulative history of regeneration events, allowing the system to adapt to changing saturation conditions throughout the engine's operation
4Duration of action of stationary object
If inaccurate oil viscosity estimation is used, then the oil change interval is extended, but the risk of engine damage increases
Solution Approach 1:
The patent implements feedback by continuously monitoring engine operating conditions and adjusting the oil viscosity estimation in real-time. This feedback mechanism allows for accurate determination of when oil changes are actually needed, extending intervals when viscosity remains acceptable while preventing extensions that would compromise engine protection
Solution Approach 2:
The patent applies preliminary action by proactively identifying when viscosity thresholds are approached before they become critical. By detecting trends in viscosity change and predicting when oil replacement will be needed, the system prevents engine damage while optimizing maintenance scheduling
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 method provides accurate oil viscosity estimation, reducing the risk of engine damage and extending oil change intervals, thereby improving engine durability and customer satisfaction without requiring complex devices.
Implementation Method 1
during normal operation of the engine, some of the fuel HydroCarbons (HC) previously adsorbed inside the oil evaporate, causing an increase of oil viscosity
Implementation Method 2
fuel from post injections more likely hits and wets the walls of the combustion chamber and is adsorbed to the oil, causing a decrease of the oil viscosity
Data Source
AI summary
A method for the estimation of oil viscosity in an internal combustion engine, the engine subjected to fuel post injections to activate Particulate Filter regeneration processes and to fuel hydrocarbons (HC) evaporation events affecting said oil viscosity. The method includes, but is not limited to determining if the particulate filter is subjected to a regeneration process and, in the affirmative case, calculating an oil viscosity decrease during said Particulate Filter regeneration process as a function of an oil dilution rate, and calculating an oil viscosity increase after said regeneration process as a function of an Hydrocarbon (HC) evaporation rate and of a time during which fuel Hydrocarbon evaporation takes place, where said evaporation time is determined as a function of a time spent in evaporating fuel Hydrocarbon from engine oil in a previous fuel hydrocarbons evaporation event.