Hydrogen Engine Combustion Mode Switching by Fuel Pressure
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Solution Overview
Problem
Conventional hydrogen internal combustion engines face low power density and efficiency compared to diesel engines, and using compressed hydrogen requires expensive onboard compressors that increase parasitic energy costs when the supply pressure drops below a certain threshold.
Innovation Solution
An apparatus and method for operating an internal combustion engine in multiple combustion modes, including diffusion, partially-premixed, and premixed combustion, with a controller determining the appropriate injection timing and pressure based on the hydrogen storage pressure, and using a compressor when necessary to maintain efficient operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If compressed hydrogen is stored at high pressure (700 bar) for late cycle direct injection, then power density and efficiency are improved, but the system requires expensive onboard compressors when supply pressure drops below the threshold
Solution Approach 1:
The system changes the pressure parameter of the hydrogen supply by switching between high-pressure stored hydrogen (700 bar) and atmospheric pressure hydrogen (1 bar), eliminating the need for continuous high-pressure compression and reducing compressor requirements
Solution Approach 2:
The system dynamically switches between different hydrogen supply modes (high-pressure stored hydrogen mode and atmospheric pressure mode) based on the hydrogen supply pressure threshold, allowing flexible adaptation to different operating conditions
2Loss of energy
If late cycle direct injection is used with compressed hydrogen, then combustion efficiency is improved, but parasitic energy costs increase due to compressor operation
Solution Approach 1:
The system changes the pressure parameter of the hydrogen supply to match the requirements of different combustion modes, using high pressure for diffusion combustion and atmospheric pressure for premixed combustion, thereby minimizing parasitic energy consumption from compression
Solution Approach 2:
The system periodically switches between different hydrogen supply pressure levels based on the operational requirements, utilizing high-pressure hydrogen when needed for diffusion combustion and atmospheric pressure hydrogen when premixed combustion is required, reducing overall energy consumption
3Adaptability or versatility
If multiple combustion modes are implemented, then adaptability to different operating conditions is improved, but control complexity increases
Solution Approach 1:
The system uses parameter changes in hydrogen injection timing and pressure to switch between combustion modes, with the controller adjusting injection timing based on supply pressure to automatically select the appropriate combustion mode
Solution Approach 2:
The system incorporates feedback from the hydrogen supply pressure sensor to the controller, which automatically adjusts the combustion mode and injection parameters based on the measured pressure, simplifying the control of multiple combustion modes
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
Improves power density and efficiency by optimizing combustion modes and reducing the need for energy-intensive compressors, thereby enhancing fuel economy.
Implementation Method 1
a fuel injector in fluid communication with the gaseous-fuel supply and configured to inject gaseous fuel directly into a combustion chamber of the internal combustion engine at an injection pressure
Implementation Method 2
the gaseous fuel substantially burns by diffusion combustion
Implementation Method 3
a compressor operatively connected with the controller for selectively pressurizing the gaseous fuel from the gaseous-fuel supply into the fuel injector
Data Source
AI summary
An apparatus and method for operating an engine in multiple combustion modes includes storing a gaseous fuel as a compressed gas; the engine is operated in a first combustion mode when an injection or storage pressure of the gaseous fuel is greater than or equal to a threshold pressure, the engine is operated in a second combustion mode when the injection or storage pressure is less than the threshold pressure; in the first combustion mode, the gaseous fuel substantially burns by diffusion combustion; and in the second combustion mode, the gaseous fuel substantially burns by one of partially-premixed combustion and premixed combustion.