Prechamber Assembly Geometry for Hydrogen Combustion Stability
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Solution Overview
Problem
Existing prechamber designs with medium pressure direct injection suffer from combustion anomalies when using less lean mixtures, limiting power and performance in internal combustion engines.
Innovation Solution
A prechamber assembly with a specific geometry, including a fuel injector, riser channel, and nozzle holes, optimized to achieve a ratio of injector area to riser channel area and injector area to nozzle hole area, which allows for improved homogeneous fuel-air mixture formation and reduced combustion anomalies, suitable for medium pressure direct injection.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Power
If medium pressure direct injection is used with less lean mixtures, then power and performance increase, but combustion anomalies occur
Solution Approach 1:
The patent applies parameter changes by optimizing the geometric ratios of the prechamber assembly components. Specifically, the injector area to riser channel area ratio is set between 0.3-0.8, and the injector area to nozzle hole area ratio is set between 0.2-1.0. These parameter optimizations enable the system to achieve homogeneous fuel-air mixing with less lean mixtures (lambda < 3) while preventing combustion anomalies, thus resolving the contradiction between power increase and combustion stability.
2Object-generated harmful factors
If lean combustion concept is used, then toxic nitric oxide production decreases, but power output is reduced
Solution Approach 1:
The patent enables operation with less lean mixtures (lambda < 3, preferably lambda < 2) by optimizing the prechamber geometry parameters. The specific ratios of injector area to riser channel area (0.3-0.8) and injector area to nozzle hole area (0.2-1.0) create optimal fuel distribution and mixing conditions. This allows the engine to achieve higher power output while maintaining reduced nitric oxide emissions compared to traditional lean combustion, effectively resolving the contradiction between emission reduction and power maintenance.
3Productivity
If medium pressure direct injection is used, then injection efficiency improves, but combustion anomalies increase with less lean mixtures
Solution Approach 1:
The patent applies local quality by creating distinct functional zones within the prechamber assembly with optimized geometric characteristics. The riser channel and nozzle holes are designed with specific area ratios relative to the injector area, creating localized flow conditions that enhance fuel-air mixing quality. This local optimization ensures homogeneous mixture formation even with less lean mixtures, maintaining combustion stability while preserving the injection efficiency advantages of medium pressure direct injection.
Solution Approach 2:
The patent optimizes critical geometric parameters of the prechamber assembly, specifically the injector area to riser channel area ratio (0.3-0.8) and injector area to nozzle hole area ratio (0.2-1.0). These parameter changes create optimal flow conditions that enhance fuel distribution and mixing efficiency, allowing the system to maintain high injection efficiency while preventing combustion anomalies with less lean mixtures.
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 optimized geometry enhances combustion homogeneity, minimizes anomalies, and increases engine power by ensuring efficient fuel distribution and ignition in the main combustion chamber, even with less lean air-fuel ratios, while reducing boost pressure demand.
Implementation Method 1
The at least one fuel injector (5) is configured to inject fuel with an injection pressure, in particular with an injection pressure having a magnitude from 20 to 50 bar
Implementation Method 2
A prechamber assembly with a specific geometry, including a fuel injector, riser channel, and nozzle holes, optimized to achieve a ratio of injector area to riser channel area and injector area to nozzle hole area, which allows for improved homogeneous fuel-air mixture formation
Implementation Method 3
wherein the at least one prechamber volume (2) has at least one ignition opening (11) with at least one ignition device (6)
Data Source
Figure 1a~1d
Figure 2a~2d
Figure 3
AI summary
Prechamber assembly (1) for an internal combustion engine, comprising: - at least one prechamber volume (2), wherein the at least one prechamber volume (2) has at least one injector opening (7) with at least one fuel injector (5) partially inserted into or attached to the at least one injector opening (7), preferably for injecting hydrogen, wherein the at least one injector opening (7) or the at least one fuel injector (5) has an injector area (8), and - at least one riser channel (3), wherein the at least one riser channel (3) is connected to the at least one prechamber volume (2), wherein the at least one riser channel (3) has a riser channel area (9), and - at least one nozzle hole (4), wherein the at least one nozzle hole (4) is connected to the at least one riser channel (3), and to a main combustion chamber (12) when the prechamber assembly (1) is in its built-in state in a combustion engine, wherein the at least one nozzle hole (4) has a nozzle hole area, wherein the at least one fuel injector (5) is configured to inject fuel with an injection pressure and that the prechamber assembly (1) is formed such that - the ratio of the injector area (8) over the riser channel area (9) is in the range of 9 to 24, preferably 12 to 18, divided by the value of the injection pressure in bar, and/or - the ratio of the injector area (8) over the nozzle hole area is in the range of 6 to 30, preferably 9 to 21, divided by the value of the injection pressure in bar.