Compression Ignition Engine Pilot Flame Igniter Low Cetane Fuel
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Solution Overview
Problem
Conventional compression ignition engines struggle to efficiently operate with low cetane number fuels, which are necessary for reducing greenhouse gas emissions, due to difficulties in auto-ignition and increased emissions of soot, carbon monoxide, and hydrocarbons.
Innovation Solution
A compression ignition engine design featuring a secondary pilot injector and an igniter, such as a glow plug, to create a pilot flame that ignites fuel from a primary main injector, allowing for efficient combustion with fuels of varying cetane numbers and reducing emissions.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If conventional compression ignition engines use high compression ratios to achieve autoignition, then thermodynamic efficiency is improved, but the engine can only operate with high cetane number fuels having high carbon content
Solution Approach 1:
The invention divides the fuel injection system into two separate injectors: a main injector for delivering the bulk fuel and a pilot injector for delivering a small amount of pilot fuel. This segmentation allows the pilot fuel to be ignited by the glow plug to create a pilot flame that ignites the main fuel, enabling the engine to operate with low cetane number fuels while maintaining high compression ratios for thermodynamic efficiency.
Solution Approach 2:
The glow plug is activated before the main fuel injection to pre-heat the pilot fuel and create a pilot flame. This preliminary action ensures that when the main fuel is injected, it is already ignited by the pilot flame, eliminating the need for the fuel to auto-ignite at compression temperatures. This allows low cetane number fuels to be used while maintaining high compression ratios.
2Object-generated harmful factors
If low carbon fuels with low cetane numbers are used in compression ignition engines, then greenhouse gas emissions are reduced, but autoignition becomes difficult and emissions of soot, carbon monoxide, and hydrocarbons increase
Solution Approach 1:
The pilot flame acts as an intermediary between the glow plug and the main fuel. The glow plug heats the pilot fuel, which then creates a pilot flame that serves as the ignition source for the main fuel. This intermediary mechanism ensures reliable ignition of low cetane number fuels without requiring high compression temperatures, thereby reducing soot, carbon monoxide, and hydrocarbon emissions while maintaining ignition reliability.
3Adaptability or versatility
If an igniter and pilot injector are added to enable low cetane fuel operation, then fuel versatility is improved, but device complexity increases
Solution Approach 1:
The pilot injector and igniter system serves multiple functions: it enables ignition of low cetane number fuels, reduces emissions of soot and carbon monoxide, and allows the engine to operate with a wide range of fuels including methanol, ethanol, dimethyl-ether, ammonia, methane, and hydrogen. By integrating these multiple functions into a single system, the invention achieves fuel versatility without proportionally increasing complexity.
4Ease of manufacture
If the cylinder head is crowded with valve openings and main injector, then ease of manufacture is maintained, but space for additional igniter and pilot injector is limited
Solution Approach 1:
The pilot injector and igniter are positioned off-center from the cylinder axis, utilizing the asymmetric available space in the cylinder head. This asymmetric placement allows the additional components to be integrated into the crowded cylinder head environment without requiring symmetric space that would be difficult to accommodate, thereby maintaining ease of manufacture while enabling the ignition system for low cetane fuels.
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 design enables the use of low cetane number fuels while significantly reducing soot, carbon monoxide, and hydrocarbon emissions, and can be integrated into existing engine designs with minimal modifications.
Implementation Method 1
An igniter is positioned along the at least one second spray axis to ignite the second spray
Implementation Method 2
high compression ratios produce temperatures and pressures that cause autoignition of introduced fuel
Implementation Method 3
create a pilot flame igniting fuel from a primary 'main' injector
Data Source
AI summary
A compression ignition engine provides a main injector and a second pilot injector producing a spray passing over an igniter producing a pilot flame assisting in ignition of the main injector spray.