Hybrid Engine Oil Dilution Control via Periodic High-Temperature Operation
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Solution Overview
Problem
In hybrid electric vehicles, prolonged fuel residence in the tank leads to fuel degradation and engine oil dilution due to infrequent engine operation, causing performance issues and potential component failure.
Innovation Solution
A vehicle controller adjusts engine starts and operations based on fuel age and oil dilution levels, intentionally operating the engine to deplete stale fuel and raise engine temperature, thereby reducing oil dilution and fuel contamination without frequent engine operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If the engine is periodically operated to deplete fuel in hybrid vehicles, then fuel degradation is reduced, but engine oil dilution is exacerbated
Solution Approach 1:
The system implements periodic engine operation at elevated temperatures specifically targeted at removing water and fuel contaminants from engine oil, while using shorter engine runs for routine fuel depletion. This periodic high-temperature operation counteracts the oil dilution caused by frequent cold starts and normal operation, resolving the contradiction between fuel stability and oil contamination.
Solution Approach 2:
The system changes the operating parameters of engine operation by introducing a specific high-temperature mode (above threshold temperature) distinct from normal operation. By monitoring engine oil dilution levels and fuel age, the controller adjusts engine operation parameters including temperature and duration to simultaneously address fuel degradation and oil contamination, resolving the harmful effect of oil dilution while maintaining fuel stability.
2Use of energy by moving object
If the engine is frequently started to improve fuel economy in HEVs, then fuel economy is improved, but oil dilution increases due to insufficient engine temperature
Solution Approach 1:
The system supplements frequent cold starts with periodic high-temperature engine operation lasting sufficient duration to raise engine temperature above thresholds and evaporate water from oil. This periodic thermal treatment occurs in addition to routine engine starts, allowing frequent operation for fuel economy while periodically correcting the oil dilution problem.
Solution Approach 2:
The system converts the harmful effect of frequent cold starts (oil dilution) into a beneficial control opportunity by monitoring dilution levels and triggering compensatory high-temperature operation. The harmful oil contamination from frequent starts becomes the trigger for a corrective action that ultimately improves oil quality by removing accumulated contaminants.
3Object-generated harmful factors
If the engine is operated at high temperature for extended duration to reduce oil dilution, then oil dilution is reduced, but fuel consumption increases
Solution Approach 1:
The system uses feedback control by continuously monitoring engine oil dilution levels and fuel age, then adjusting engine operation parameters accordingly. The controller determines whether high-temperature operation is actually needed based on measured conditions, triggering such operation only when dilution exceeds thresholds or fuel is sufficiently aged, thereby minimizing unnecessary fuel consumption while addressing oil dilution problems.
Solution Approach 2:
The system dynamically changes engine operation parameters (temperature and duration) based on real-time monitoring of oil dilution and fuel age. Rather than using fixed extended high-temperature operation, the controller adjusts parameters to match actual needs, using higher temperatures and longer durations only when necessary to remove contaminants, thus optimizing the balance between oil quality improvement and fuel consumption.
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 effectively reduces fuel degradation and oil dilution, improving hybrid vehicle performance while maintaining drivability without unnecessary engine operation.
Implementation Method 1
at least some of the contaminating water can be removed (e.g., evaporated) during engine warm-ups
Data Source
AI summary
Methods and systems are provided for operating an engine in a hybrid vehicle in response to fuel and water dilution of engine lubricating oil. An engine oil dilution counter may be adjusted based on a number of engine hot starts and duration of engine operation above a threshold temperature. In addition, the counter may be adjusted if the engine is started to deplete stale fuel in the fuel tank.