Hydrogen Engine Piston Bowl Mixing to Reduce NOx
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Solution Overview
Problem
Existing hydrogen internal combustion engine systems face challenges in the interplay between fuel injection and mixing of fuel and compressed air within the combustion chamber, leading to inefficient combustion and higher NOx emissions.
Innovation Solution
An internal combustion engine system with a controllable fuel injector that injects gaseous fuel towards a piston bowl prior to ignition, utilizing a piston bowl design to enhance mixing of hydrogen fuel and oxygen, and a controller to manage fuel injection parameters.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Quantity of substance
If gaseous fuel is injected into the combustion chamber without specific directional control, then the fuel injection process is simple, but the mixing of fuel and compressed air is inefficient
Solution Approach 1:
The fuel injector is configured to pre-direct fuel jets toward the piston bowl before compression reaches its peak, allowing fuel and air to begin mixing in advance during the compression stroke, thereby improving mixing efficiency without requiring additional complex mechanisms
Solution Approach 2:
The piston bowl geometry is specifically designed with a defined bottom surface orientation that locally concentrates and directs the fuel-air mixture toward specific regions, enhancing mixing in critical zones without requiring overall system complexity
2Reliability
If fuel injection timing is delayed, then the combustion process is simpler to control, but homogeneous mixing conditions cannot be achieved leading to end-gas ignition
Solution Approach 1:
Fuel injection is initiated at a precisely controlled timing point during the compression stroke, allowing sufficient time for homogeneous mixing before ignition, preventing end-gas knock while maintaining reliable combustion through optimized injection scheduling
Solution Approach 2:
The controller uses feedback from engine operating conditions to dynamically adjust fuel injection timing and duration, ensuring optimal homogeneous mixing conditions are achieved across varying loads and speeds while maintaining combustion stability
3Power
If fuel is injected without optimized mixing, then the engine power output is lower, but the injection and mixing process is less complex
Solution Approach 1:
The piston bowl is designed with a specific bottom surface orientation that locally optimizes fuel jet interaction with the incoming air stream, creating efficient mixing zones that maximize power output without requiring complex overall engine redesign
Solution Approach 2:
The fuel injector and piston bowl geometry work together to pre-establish optimal mixing conditions during the compression stroke, ensuring high-quality fuel-air mixture is ready for ignition, thereby maximizing power output through advance preparation rather than complex combustion chamber design
4Object-generated harmful factors
If conventional fuel injection is used, then the system is simpler, but NOx emissions are higher due to inefficient combustion
Solution Approach 1:
Fuel is injected and begins mixing with compressed air during the compression stroke before ignition, ensuring complete and efficient combustion that minimizes NOx formation through optimized combustion characteristics rather than post-combustion treatment
Solution Approach 2:
The oriented piston bowl bottom surface creates localized mixing enhancement that promotes uniform combustion and reduces peak temperatures and pressures that lead to NOx formation, achieving emission reduction through geometric optimization
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 fuel mixing and combustion efficiency, reduces emissions, and achieves homogeneous conditions to avoid end-gas ignition, resulting in high engine power output with low emissions.
Implementation Method 1
guide the fuel-jet(s) by re-directing the fuel-jets primarily upwards, i.e. in the direction the piston travels to reach TDC, and/or split the fuel jets, thereby improving mixing of the gaseous fuel and oxygen prior to ignition
Implementation Method 2
a controllable fuel injector arranged to inject gaseous fuel into the combustion chamber and towards the piston bowl
Implementation Method 3
a reciprocating piston moveable within the cylinder between a bottom dead centre BDC and a top dead centre TDC
Implementation Method 4
ignition of the mixed fuel in the combustion chamber of the ICE
Data Source
AI summary
An internal combustion engine, system includes an internal combustion engine for combustion of gaseous fuel and having a combustion chamber at least partially delimited by a cylinder; a reciprocating piston moveable within said cylinder between a bottom dead centre (BDC) and a top dead centre (TDC), The reciprocating piston has a piston top end comprising a piston bowl intended to form part of the combustion chamber. A controllable fuel injector is arranged to inject gaseous fuel into the combustion chamber and towards the piston bowl. A controller controls the fuel injector to inject at least one gaseous fuel jet toward a bottom surface of the piston bowl during a fuel injection period occurring prior to an ignition event of the gaseous fuel.