Engine Fuel Property Detection via Crank Angle Period
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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, rapid combustion, or inefficient combustion, due to varying additives and biofuel properties.
Innovation Solution
A method involving an in-cylinder pressure sensor and a crank angle sensor that measures the crank angle period after fuel injection during the compression stroke to determine the fuel properties by comparing it to a reference period of standard fuel, allowing for precise adjustment of fuel injection timing and intake valve closure to match standard fuel behavior.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If the engine control system uses standard fuel properties for control, then the control is simple and straightforward, but the combustion performance deteriorates when non-standard fuel is supplied
Solution Approach 1:
The system dynamically changes control parameters (fuel injection timing, intake valve closure timing) based on detected fuel properties. The controller adjusts these parameters according to the measured crank angle period to maintain optimal combustion performance regardless of fuel type variations.
Solution Approach 2:
The system automatically detects fuel properties and self-adjusts control parameters without external intervention. The fuel property detection and control parameter adjustment form a closed-loop system that adapts to different fuel types autonomously.
2Reliability
If the engine control system detects fuel properties accurately, then the combustion performance is maintained, but the system complexity increases
Solution Approach 1:
The system uses the existing in-cylinder pressure sensor and crank angle sensor as intermediaries to indirectly detect fuel properties. By measuring the crank angle period from intake valve closure to peak pressure, the system derives fuel properties without requiring dedicated fuel analysis equipment.
Solution Approach 2:
The system replaces complex chemical fuel analysis with a mechanical measurement approach. Instead of using sophisticated fuel composition analyzers, the system uses pressure-time measurements during the compression stroke to infer fuel properties such as boiling point and latent heat of vaporization.
3Productivity
If the crank angle period measurement is used to determine fuel properties, then the measurement is simple and fast, but the precision may be insufficient for accurate fuel property determination
Solution Approach 1:
The system performs preliminary measurement of the crank angle period during the compression stroke before combustion occurs. This early measurement allows the controller to adjust control parameters in advance for the upcoming combustion cycle, ensuring optimal performance from the first injection.
Solution Approach 2:
The system uses feedback from the measured crank angle period to continuously adjust control parameters. The controller compares the measured period with reference values and modifies fuel injection timing and intake valve closure timing accordingly, creating a closed-loop control system that improves measurement effectiveness through iterative adjustment.
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 method enables accurate determination of fuel properties, improving fuel efficiency, reducing combustion noise, and enhancing emission performance by adjusting fuel injection and intake valve timing based on the fuel's boiling point and latent heat of vaporization, ensuring combustion equivalent to that of standard fuel.
Implementation Method 1
outputting, by an in-cylinder pressure sensor, to a controller a signal indicative of a reference pressure corresponding to a pressure change inside a cylinder
Implementation Method 2
creating a heat release rate waveform of a low-temperature oxidation reaction, after fuel is injected into a cylinder
Implementation Method 3
a reaction start timing of fuel according to a period during which the fuel floats so as to be on a more advancing side
Implementation Method 4
determining the composition of a fuel mixture from combustion chamber pressure curves after a fuel injection during a compression stroke for fuels with different boiling points and enthalpy of evaporation
Data Source
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AI summary
An engine controlling method is provided, which includes, during motoring of the engine, outputting, by an in-cylinder pressure sensor, to a controller a signal indicative of a reference pressure corresponding to a pressure change after an intake valve of a cylinder of the engine is closed when not performing fuel injection, and then injecting, by an injector, fuel for analysis into the cylinder at a specific timing after the intake valve is closed. The method includes, by the controller, acquiring a crank angle period from the intake valve close timing, through the fuel injection, to a timing of the in-cylinder pressure reaching the reference pressure based on signals from the in-cylinder pressure sensor and a crank angle sensor, and determining a property of the injected fuel by comparing the acquired crank angle period with that of a standard fuel based on stored information on a property of the standard fuel.