Hybrid Engine Stop Control for Fuel Dilution in Oil
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Solution Overview
Problem
Fuel dilution in engine oil of hybrid electric vehicles leads to decreased viscosity and degradation, causing increased component wear and shorter service intervals due to unburned fuel entering the oil during non-stoichiometric conditions.
Innovation Solution
Implementing methods and apparatus to detect engine and turbine temperatures, limiting engine torque during high-speed/high-load operations, inhibiting engine stops at low oil temperatures, and applying torque multiplication to reduce fuel injection, thereby promoting fuel evaporation from the oil.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If the engine is stopped frequently to save fuel in hybrid electric vehicles, then fuel economy is improved, but fuel accumulates in the engine oil when the oil temperature is below the threshold, leading to oil degradation and increased wear
Solution Approach 1:
The system performs preliminary detection of engine oil temperature and predicts fuel accumulation risk before actual fuel dilution occurs. By detecting temperature below the threshold and predicting fuel in oil conditions in advance, the system takes preventive action by inhibiting engine stop, thus avoiding the harmful effect of fuel accumulation in the oil
Solution Approach 2:
The system continuously monitors engine operating conditions and oil temperature, using this feedback to dynamically control engine stop/start operations. The control unit receives temperature data and adjusts engine operation accordingly, creating a closed-loop control system that adapts to changing conditions to prevent fuel dilution
2Reliability
If the engine is kept running to evaporate fuel from the oil, then fuel dilution is reduced, but fuel consumption increases and service interval decreases
Solution Approach 1:
The system changes the operational parameters by introducing temperature-based control logic. When oil temperature exceeds the threshold, the system allows normal stop/start operation; when temperature is below the threshold, it modifies operation by inhibiting engine stop. This parameter-based control optimizes the balance between fuel economy and oil quality protection
Solution Approach 2:
The system applies partial action by selectively inhibiting engine stop only under specific conditions (when temperature is below threshold and fuel accumulation is predicted). It does not prevent all engine stops, but rather applies targeted intervention only when necessary to prevent fuel dilution, thus minimizing impact on fuel economy while protecting oil quality
3Reliability
If engine stop is inhibited to prevent fuel accumulation, then oil degradation is reduced, but user convenience decreases due to limited electric vehicle mode availability
Solution Approach 1:
The system provides preliminary warning to the user by displaying a notification that electric vehicle mode will be unavailable or limited. This advance notice allows the user to plan accordingly and understand the temporary restriction, reducing the negative impact on user convenience while still implementing the necessary engine operation modification to protect oil quality
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
Prevents fuel buildup in engine oil by maintaining engine operation at low temperatures, reducing wear and extending service intervals while indicating operational variations to users.
Implementation Method 1
maintaining an engine in an on condition for a longer period to encourage the evaporation of fuel from the engine oil
Implementation Method 2
encourage the evaporation of fuel from the engine oil
Data Source
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AI summary
A method (200) and apparatus 10-2 for carrying out the method of mitigating fuel in oil in an internal combustion engine of a hybrid electric vehicle, the method comprising: detecting a first engine start of a drive cycle when the vehicle speed is greater than zero (210); detecting a temperature of engine oil in the engine at the first engine start of the drive cycle (220); determining if the temperature of the engine oil is below an engine oil temperature threshold (230); when the temperature of the engine oil is determined to be below the engine oil temperature threshold, inhibiting an engine stop for a first predetermined time period unless the vehicle speed reaches zero (240).