Fuel Injection Compensation for PCV Fuel Dilution
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Solution Overview
Problem
Fuel injection systems fail to account for engine oil fuel dilution, leading to inefficient combustion, misfires, and degraded engine performance, particularly in hybrid vehicles where oil contamination occurs before sufficient heating allows for fuel evaporation.
Innovation Solution
A method to adjust fuel injection based on engine oil fuel dilution, determined by parameters such as oil volume, temperature, engine speed, and load, with selective PCV gas flow into the intake system to account for fuel vapor, thereby improving combustion efficiency and reducing misfires and stalls.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Productivity
If fuel injection is increased to compensate for fuel dilution in oil, then combustion efficiency improves, but the risk of rich stalls and misfires increases during PCV purge operations
Solution Approach 1:
The fuel injection system dynamically adjusts injection quantities based on real-time operating conditions (engine load, speed, temperature) and detected fuel dilution levels. The controller continuously modifies injection parameters to compensate for fuel vapor entering through PCV while preventing over-injection that could cause rich stalls, thereby resolving the contradiction between maintaining combustion efficiency and ensuring operational stability.
Solution Approach 2:
The system implements feedback control by monitoring engine operating parameters and detected fuel dilution conditions, then using this information to adjust fuel injection quantities. The controller receives feedback on actual combustion performance and oil fuel content, continuously refining injection strategies to optimize combustion efficiency while avoiding rich stalls and misfires during PCV purge operations.
2Quantity of substance
If the engine operates for limited duration as in hybrid vehicles, then fuel dilution in oil increases before sufficient heating allows evaporation, but extended operation to heat oil may cause degraded starts and delays
Solution Approach 1:
The system performs preliminary compensation for fuel dilution by detecting fuel content in oil and pre-adjusting fuel injection quantities before PCV purge operations begin. This preliminary action accounts for the accumulated fuel dilution that occurs during limited engine operation in hybrid vehicles, allowing the engine to maintain proper combustion balance without requiring extended warm-up operation that would cause start-up delays.
Solution Approach 2:
The control system changes operating parameters (fuel injection quantity, timing) based on detected fuel dilution levels and engine temperature conditions. By monitoring parameters such as oil temperature, engine load, and speed, the system dynamically adjusts fuel injection to compensate for fuel vapor release during PCV operations, enabling proper combustion balance to be achieved without extended operation that would cause start-up delays.
3Productivity
If fuel vapor from crankcase flows through PCV system into intake conduit, then combustion efficiency degrades causing misfires and stalls, but reducing PCV flow increases crankcase pressure and affects lubrication
Solution Approach 1:
The system extracts and compensates for the harmful effect of fuel vapor entering through PCV by detecting fuel dilution in oil and adjusting fuel injection quantities accordingly. Rather than blocking PCV flow (which would affect lubrication), the system takes out the harmful fuel vapor component by accounting for it in the fuel injection strategy, thereby maintaining combustion efficiency without compromising the lubrication system.
Solution Approach 2:
The system converts the harmful effect of fuel dilution into a beneficial control parameter. By detecting fuel content in the oil, the system uses this previously harmful condition as information to optimize fuel injection timing and quantity. The fuel vapor that would otherwise cause misfires and stalls is now accounted for in the control strategy, transforming a harmful phenomenon into a useful feedback signal for improving combustion efficiency while maintaining proper PCV flow for lubrication.
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 enhances combustion efficiency, reduces emissions, and minimizes the likelihood of misfires and stalls by accurately accounting for fuel dilution in the engine oil, improving overall engine performance.
Implementation Method 1
fuel may slip past the piston via fuel remaining on the walls of the cylinder during combustion... Fuel may slip past the piston into a crankcase housing engine oil... Fuel (e.g., fuel vapor) from the crankcase may flow through the PCV system into an engine intake conduit
Implementation Method 2
the oil may be contaminated by a large amount of fuel before the oil is sufficiently heated to allow for evaporation of the fuel from the oil
Data Source
AI summary
A method for controlling an internal combustion engine based on the amount of un-burned fuel dissolved in the engine oil, and returned into the manifold through the PCV valve as the engine oil temperature rises via adjusting fuel injection into a cylinder from a fuel injector, in a fuel delivery system. The fuel dilution in engine oil and the amount of fuel entering the intake manifold through the PCV valve can be determined based on one or more of oil volume, fuel composition (e.g., ethanol content), oil temperature, engine temperature, engine speed, engine load, engine run time, injected fuel mass, and exhaust gas composition.