Adjustable Injection Timing for Accurate Cetane Number Determination

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Solution Overview

Problem

Existing methods for determining the cetane number of fuels, such as the BASF engine and Fuel Ignition Analyzers, fail to accurately represent the conditions in modern diesel engines, leading to inaccurate fuel classification and inability to test all types of diesel fuels, especially those with different viscosities and surface tensions.

Innovation Solution

A method that adjusts the start of injection to achieve maximum engine performance with unchanged injection quantity and pressure, using a modern single-cylinder diesel engine test setup with adjustable start of injection and continuous injection, allowing for reproducible cetane number determination across various diesel fuels.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Reliability

If a fixed start of injection is used in the BASF test engine, then the ignition delay can be set to a standard value (20° CA), but the method cannot accurately represent conditions in modern diesel engines and cannot test all fuel types

Engineering Contradiction:

Improvereproducibility of ignition delay measurementVSAvoidapplicability to different fuel types and modern engine conditions

Core Design Contradiction:

ReliabilityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by making the start of injection adjustable rather than fixed. The injection timing can be varied to optimize combustion for different fuel types while maintaining reproducible measurement conditions. This allows the test engine to adapt to diverse fuels (petroleum-based, biofuels, vegetable oils) while preserving the reliability of cetane number determination through controlled variation of injection parameters.

Inventive Principle:

Principle #15Dynamics

Solution Approach 2:

The patent changes key operating parameters including injection pressure, start of injection timing, and injection quantity to match modern diesel engine conditions. By adjusting these parameters, the test method becomes versatile enough to handle fuels with different viscosities and combustion characteristics while maintaining accurate cetane number measurement through standardized evaluation criteria.

Inventive Principle:

Principle #35Parameter changes

2Measurement precision

If the combustion air is throttled to achieve a fixed ignition delay of 20° CA, then the cetane number can be determined using the BASF engine, but the measurement does not reflect optimal combustion conditions and gives distorted results for modern fuels

Engineering Contradiction:

Improveaccuracy of cetane number determinationVSAvoidrelevance to modern diesel engine operation

Core Design Contradiction:

Measurement precisionVSReliability

Solution Approach 1:

Instead of throttling combustion air to achieve a fixed ignition delay, the patent inverts the approach by adjusting the start of injection timing to achieve optimal combustion. The ignition delay is no longer forced to a fixed 20° CA value but is allowed to vary naturally with fuel properties, while the measurement methodology is inverted to determine cetane number based on optimal performance characteristics rather than standardized throttling conditions.

Inventive Principle:

Principle #13The other way round (Inversion)

3Device complexity

If the injection pressure is kept low in the BASF test engine, then the engine structure remains simple, but the injection spray break-up is insufficient and cannot accommodate fuels with different viscosities

Engineering Contradiction:

Improvesimplicity of test engine structureVSAvoidcapability to handle diverse fuel viscosities

Core Design Contradiction:

Device complexityVSAdaptability or versatility

Solution Approach 1:

The patent applies dynamics by implementing adjustable injection pressure capability in the test engine. Rather than using a fixed low injection pressure, the system can dynamically adjust injection pressure to achieve proper spray break-up for different fuel viscosities. This maintains structural simplicity while enhancing versatility to test petroleum-based fuels, biofuels, and vegetable oils with varying physical properties.

Inventive Principle:

Principle #15Dynamics

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 and reproducible cetane number determination for a wide range of diesel fuels, including those previously untestable with traditional methods, by optimizing the start of injection to match modern diesel engine conditions, providing a more relevant measurement of fuel ignitability.

Implementation Method 1

In order to determine the cetane number of a fuel, it is usually compared with various test substances made from a mixture of cetane and alpha-methyl-naphthalene... The start of ignition is determined by a pressure sensor via the increase in pressure in the cylinder

Methodology Applied

Scientific EffectCombustion: Combustion

Data Source

PatentEP2657698B1Method for determining the cetane number of fuels

Publication Date: 2019.01.09 REGINEERING

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Figure 4

AI summary

The method involves determining cetane number of the test fuel by a comparison with a set of test media with known cetane number. The injection start for determined test fuel is checked, to increase the performance of test engine (1). The test engine is operated at an uninterrupted, continuous injection condition. The validation of the test engine is performed at predetermined intervals.