Diesel Engine Cetane Number Determination via Crankshaft Angle Variation
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Solution Overview
Problem
Existing methods for determining the cetane number of fuels in diesel engines require specialized equipment and additional sensors, making it impractical for standard engines.
Innovation Solution
A method involving a series of fuel injections with varying crankshaft angles in one cylinder, measuring engine speed changes, and using pre-stored relationships to determine cetane number without additional sensors, allowing for standard engine use.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Measurement precision
If a standard single cylinder Diesel engine with variable compression ratio is used to determine cetane number, then measurement precision is improved, but device complexity increases and ease of operation deteriorates
Solution Approach 1:
The patent makes a standard diesel engine multi-functional by enabling it to perform both its primary function (power generation) and a secondary function (cetane number determination). The existing engine components are utilized for measurement purposes without requiring a specialized test engine, thus resolving the contradiction between measurement precision and device complexity.
Solution Approach 2:
The engine serves itself by using its own operational parameters (speed, temperature, pressure) for cetane number determination. The measurement process leverages the engine's self-generated data from normal operation, eliminating the need for external specialized equipment and reducing overall system complexity while maintaining measurement accuracy.
2Measurement precision
If additional sensors are added to measure combustion parameters, then measurement precision is improved, but device complexity and cost increase
Solution Approach 1:
The engine's existing sensors and control systems are repurposed to provide measurement data for cetane number determination. The ECU utilizes data from sensors already present in the engine (such as crankshaft position sensors, pressure sensors, and temperature sensors) to perform combustion analysis, eliminating the need for additional specialized sensors while maintaining measurement precision.
Solution Approach 2:
Existing engine components and sensors are made multi-functional, serving both their original control functions and new measurement functions for cetane number determination. This approach allows the system to extract multiple types of information from the same hardware resources, reducing overall system complexity.
3Measurement precision
If a specialized test engine is used for cetane number determination, then measurement precision is improved, but ease of operation deteriorates and adaptability decreases
Solution Approach 1:
The patent enables standard diesel engines to perform cetane number determination, making the capability universal across different engine models and manufacturers. This approach eliminates the need for specialized test engines and allows the measurement function to be applied broadly across the diesel engine fleet, significantly improving adaptability while maintaining measurement precision through standardized measurement protocols.
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
Enables accurate cetane number determination in standard diesel engines without specialized equipment, improving combustion efficiency by correlating engine speed changes with injection timing.
Implementation Method 1
The cetane number of a fuel (e.g. Diesel) provides a measure of the ignition characteristics when used in compression ignition engines
Implementation Method 2
measuring engine speed at intervals during said series of injections and determining values for changes in engine speed consequent to said injections
Data Source
AI summary
A method of determining the cetane number of a fuel in an internal combustion engine comprising, during running of the engine, i) with respect to one cylinder, performing a routine including a series of injections such that for each injection a quantity of fuel is injected into the cylinder, and during the routine varying the angle at which the injections takes place with respect to crankshaft angle; ii) measuring engine speed at intervals during the series of injections and determining values for changes in engine speed consequent to the injections; iii) determining cetane number from a pre-stored relationship relating the cetane number to changes in engine speed consequent to changes in the test injection angle.