Gas Fuel Injection Unit for Internal Combustion Engine
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Solution Overview
Problem
Dual fuel engines operating in gas fuel mode experience fuel slip, leading to greenhouse gas emissions due to uncombusted gas fuel being expelled from the cylinder, which is not efficiently managed by existing technologies.
Innovation Solution
A method and gas fuel injection unit that directly injects gas fuel into the combustion chamber at a maximum pressure lower than the compression-end pressure, using a gas fuel injection valve and feed unit, preventing uncombusted fuel expulsion by controlling the injection timing and pressure relative to the engine cycle.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If the inlet valve and outlet valve remain open for overlapping time period during intake stroke to flush the cylinder with gas-air mixture, then the combustion chamber is cooled to prevent high combustion temperatures, but uncombusted gas fuel is expelled from the cylinder causing fuel slip and greenhouse gas emissions
Solution Approach 1:
The gas fuel is injected into the combustion chamber before the intake stroke begins, specifically before the inlet valve opens. This preliminary injection ensures that the gas fuel is already present in the combustion chamber and will not be expelled when the valves overlap during the intake stroke, thereby preventing fuel slip while still allowing the valve overlap cooling mechanism to function
Solution Approach 2:
The harmful effect of fuel slip is eliminated by separating the gas fuel injection timing from the valve overlap period. The gas fuel injection is extracted from the intake stroke timing and performed independently before the intake stroke begins, preventing the gas fuel from being expelled during valve overlap
2Manufacturing precision
If gas fuel is injected at high pressure to improve injection precision and control, then the injection timing and amount can be better controlled, but the injection pressure may exceed the compression-end pressure causing improper combustion chamber conditions
Solution Approach 1:
The injection pressure parameter is specifically controlled to be lower than the compression-end pressure of the engine. This parameter change ensures that while sufficient pressure is maintained for precise injection control and proper fuel atomization, the pressure does not exceed the compression-end pressure, thereby maintaining appropriate combustion chamber conditions
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 approach enhances operational efficiency and reduces environmental impact by minimizing fuel slip and emissions, allowing for more precise control over gas fuel supply and combustion, thereby operating the engine in a more environmentally friendly manner.
Implementation Method 1
directly injecting a gas fuel into a combustion chamber of the engine at a maximum injection pressure that is lower than a compression-end pressure of the engine
Implementation Method 2
a gas fuel feed unit configured for supplying pressurized gas fuel to the gas fuel injection valve
Data Source
AI summary
The present invention relates to a method for operating an internal combustion engine provided as a medium-speed gas engine or dual fuel engine in a gas fuel mode. The method comprises the step of directly injecting a gas fuel into a combustion chamber of the engine at a maximum injection pressure that is lower than a compression-end pressure of the engine.