Crankcase Breather Fuel Flow Control for Engine Diagnostics
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Solution Overview
Problem
Internal combustion engines face issues with fuel dissolving in lubricants during cold starts, leading to undesirable changes in lubricating properties, increased wear, and misinterpretation of engine malfunctions due to fuel evaporation into the intake tract via the crankcase breather, limiting diagnostic capabilities, especially in short-term operations.
Innovation Solution
A method that measures and monitors the mass flow of fuel from the crankcase into the intake tract based on operating parameters, adjusting fuel-air ratios, and using a model parameter to account for fuel dissolved in the lubricant, allowing for precise control and monitoring of engine operability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If the crankcase breather vents into the intake tract to prevent fuel emission, then environmental protection is improved, but the control system misinterprets fuel-riching as engine malfunction
Solution Approach 1:
The control system preemptively adjusts the fuel metering quantity based on detected operating conditions (cold start, high load, high speed) before the fuel evaporation and riching occurs. This preliminary compensation prevents the fuel-air mixture from becoming too rich, allowing normal crankcase breather operation without triggering false malfunction diagnoses.
Solution Approach 2:
The control system dynamically changes the fuel metering parameter (fuel quantity) based on operating conditions. By increasing fuel injection during cold starts, high load, or high speed operations, the system compensates for the fuel that will evaporate from the lubricant and enter through the crankcase breather, maintaining proper fuel-air ratios without misinterpreting the process as a malfunction.
2Power
If fuel is injected directly into the combustion chamber to improve combustion efficiency, then power output is improved, but fuel dissolves in the lubricant causing increased wear
Solution Approach 1:
The control system dynamically adjusts the fuel injection parameter (quantity and timing) based on engine operating conditions. During cold starts or conditions where lubricant temperature is low, the system modifies fuel injection to account for the increased tendency of fuel to dissolve in the lubricant, thereby reducing fuel-related wear while maintaining combustion efficiency during normal operation.
3Measurement precision
If the control system monitors fuel-air ratio to detect malfunctions, then diagnostic capability is improved, but normal fuel evaporation from lubricant is misinterpreted as malfunction
Solution Approach 1:
The control system uses feedback from operating condition sensors (temperature, load, speed) to continuously adjust fuel metering. This closed-loop control compensates for the fuel that evaporates from the lubricant and enters through the crankcase breather, maintaining accurate fuel-air ratios and preventing false malfunction detections while preserving the ability to detect actual anomalies.
Solution Approach 2:
The system preemptively adjusts fuel metering based on predicted fuel evaporation conditions (cold start, high load, high speed) before the evaporation occurs. This preliminary compensation ensures that the fuel-air ratio remains within acceptable ranges, preventing the monitoring system from misinterpreting normal evaporation as a malfunction.
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 enables more accurate control and monitoring of engine operability, differentiating between normal fuel evaporation and malfunction states, thereby enhancing diagnostic capabilities and reducing wear, and improving engine longevity.
Implementation Method 1
fuel may be dissolved in a lubricant of the internal combustion engine, then evaporate again as the operating temperature increases
Implementation Method 2
fuel may condense on the oil film on the cold wall of the combustion chamber and dissolve in the oil film
Data Source
AI summary
In a method for operating an internal combustion engine with a crankcase breather venting into an intake tract, operating parameters of the internal combustion engine are measured 102. A mass flow of fuel from the crankcase into the intake tract is determined as a function of the operating parameters measured 103. The internal combustion engine is controlled 111 or monitored 108 as a function of the mass flow of fuel from the crankcase into the intake tract.