Engine Fuel Property Detection via In-Cylinder Pressure Analysis
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Solution Overview
Problem
Existing engine control systems struggle to accurately determine the properties of fuel supplied to engines, particularly when the fuel differs from standard fuel, leading to potential misfire or rapid combustion, which can result in reduced engine efficiency and increased combustion noise.
Innovation Solution
A method involving the injection of fuel for analysis during engine motoring, with an in-cylinder pressure sensor measuring pressure changes to compare with reference values, allowing the controller to determine the fuel's heat release properties and adjust fuel injection timing and amount accordingly to match standard fuel behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the controller uses predetermined fuel injection timing and amount based on standard fuel properties, then the control system is simple and easy to operate, but the engine may experience misfire or rapid combustion when non-standard fuel is supplied
Solution Approach 1:
The system performs preliminary fuel property measurement during engine motoring (before normal operation) by injecting analysis fuel and measuring in-cylinder pressure. This advance detection of fuel properties allows the controller to adjust injection parameters before actual combustion begins, preventing misfire or rapid combustion while maintaining operational simplicity.
Solution Approach 2:
The system establishes a feedback loop where fuel property measurement results from pressure comparison are used to dynamically adjust fuel injection timing and amount. The controller continuously monitors fuel properties and modifies injection parameters accordingly, ensuring reliable combustion adaptation while keeping the control interface simple for users.
2Reliability
If the controller adjusts fuel injection parameters to adapt to different fuel properties, then combustion stability is maintained, but the device complexity increases due to additional sensors and measurement systems
Solution Approach 1:
The in-cylinder pressure sensor serves multiple functions: it monitors normal engine operation and simultaneously measures fuel properties during motoring. By making the pressure sensor multi-functional, the system avoids adding dedicated measurement sensors, thereby maintaining combustion stability while minimizing device complexity.
Solution Approach 2:
The engine's own compression process during motoring is utilized to perform fuel property measurement without requiring external test equipment. The system uses the naturally occurring pressure changes during compression to detect fuel characteristics, making the engine itself serve the measurement function and avoiding additional complex measurement apparatus.
3Measurement precision
If fuel property measurement is performed during engine operation, then the engine can adapt to fuel variations, but high-temperature oxidation reactions occur that interfere with accurate property determination
Solution Approach 1:
Fuel property measurement is performed during engine motoring before normal combustion operation begins. This preliminary measurement occurs at lower temperatures where high-temperature oxidation reactions have not yet started, ensuring accurate fuel property determination without thermal interference. The results are then used to optimize injection parameters for subsequent high-temperature operation.
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 precise determination of fuel properties, ensuring optimal combustion efficiency, reducing noise, and improving engine performance by adjusting fuel injection parameters based on the analyzed fuel characteristics.
Implementation Method 1
an in-cylinder pressure sensor outputs to a controller a signal corresponding to a pressure inside the cylinder
Implementation Method 2
The fuel injected into the cylinder results in the low-temperature oxidation reaction according to the progress of time
Implementation Method 3
If the property of fuel (for example, a ratio of specific heat and/or a gas constant of fuel) differs, the amount of heat released also differs
Implementation Method 4
injecting, during motoring of the engine, by an injector, fuel for analysis into a cylinder at a specific timing
Data Source
AI summary
A method of controlling an engine is provided, which includes the steps of, during motoring of the engine, injecting, by an injector, fuel for analysis into a cylinder at a specific timing after an intake valve of the cylinder of the engine is closed, outputting to a controller, by an in-cylinder pressure sensor, a signal corresponding to a pressure inside the cylinder at least at a timing when a specific crank angle period has passed from the fuel injection timing, and determining, by the controller, a property of the fuel injected by the injector, by comparing a pressure value measured by the in-cylinder pressure sensor with a reference pressure value inside the cylinder measured at a timing when the specific crank angle period has passed after a standard fuel is injected into the cylinder at the specific timing.