Masked Intake Valve Flame Deck for Hydrogen Engine Tumble Flow
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Solution Overview
Problem
Hydrogen-fueled spark-ignition internal combustion engines derived from compression-ignition engines face challenges in generating a tumble motion and using a variable valve timing device due to the inherent under-optimized geometry and interference issues between intake valves and pistons, which affect combustion efficiency and mixing.
Innovation Solution
The engine design incorporates a recessed flame deck with a curtain that masks intake valves to enhance tumble motion generation and allows for variable valve timing without interference, by creating a depression in the head to accommodate valve movement and reduce collisions with the piston.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the engine uses an architecture derived from compression-ignition engines with vertically arranged valves, then the engine can withstand high mechanical stresses from hydrogen combustion, but the valve masking is impossible due to the flat flame deck geometry
Solution Approach 1:
The invention transitions from a two-dimensional flat flame deck to a three-dimensional recessed flame deck structure. By creating a depression in the flame deck that extends toward the cylinder, the design provides the vertical space necessary for valve masking while preserving the compression-ignition engine architecture's mechanical strength characteristics.
2Productivity
If valve masking is implemented to generate tumble motion, then combustion efficiency improves, but volumetric efficiency deteriorates due to reduced outflow area
Solution Approach 1:
The invention segments the flame deck into multiple levels: a recessed region for valve masking and a raised region for valve operation. This segmentation allows the masking curtain to be formed in the recessed area while preserving sufficient outflow area in the raised region, thus balancing tumble motion generation with volumetric efficiency.
3Productivity
If variable valve timing is implemented to optimize hydrogen injection and mixing, then combustion efficiency improves, but interference between intake valves and piston occurs due to limited space
Solution Approach 1:
By creating a recessed flame deck that extends into the cylinder space, the invention provides additional vertical clearance that allows the intake valves to be positioned lower. This extra space enables the implementation of variable valve timing mechanisms without causing interference between the valves and the piston at top dead center.
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
The solution enables efficient tumble motion and mixing of hydrogen-air mixtures while supporting variable valve timing, enhancing combustion efficiency and reducing mechanical stress on the engine components.
Implementation Method 1
the generation of a tumble motion (vortex T, Figure 2) of the charge within the cylinder
Implementation Method 2
a speed of the flame front which is much higher than in the case of the combustion of carbon-based fuel
Implementation Method 3
a very high resistance to detonation
Data Source
Figure 1
Figure 2
Figure 3
AI summary
There is described a hydrogen-fueled spark-ignition internal combustion engine (1). The engine derives its architecture from a compression-ignition engine, and includes a flame deck of the combustion chamber which is shaped in such a way as to implement a masking of the intake valves, and at the same time to eliminate the risks of collision between the intake valves (4) and the piston (P). If a phase shifter is adopted, the engine according to the invention enables varying the starting instant of the opening of the intake valve, even in advance, without interfering with piston (P).