Hydrogen Fuel-Water Injection Assembly for Preignition and NOx Reduction
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Solution Overview
Problem
Existing systems fail to efficiently inject hydrogen gas and water together in spark ignition engines due to the high reactivity of hydrogen, leading to preignition and NOx formation, and require separate injectors which are difficult to accommodate in engine compartments.
Innovation Solution
An injection device that combines gaseous fuel and water through a mixing device with a valve assembly, using a valve needle to control the delivery of the mixture into the combustion space, allowing for precise control of water quantity and timing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If separate water injector and fuel injector are used, then water and fuel can be injected effectively, but device complexity increases and packaging becomes difficult
Solution Approach 1:
The patent combines the water injection function and fuel injection function into a single integrated injector assembly. The injector housing contains both a water injection nozzle and a fuel injection nozzle, allowing both substances to be delivered through one component. This merging eliminates the need for separate injectors, reducing device complexity while maintaining the reliability of effective water and fuel injection.
2Object-affected harmful factors
If high water/fuel ratio is used, then preignition and NOx are reduced, but water consumption increases
Solution Approach 1:
The patent employs a vaporizer assembly that heats water to generate vapor, changing the physical state of water from liquid to gas. This parameter change allows water to be introduced in a form that more effectively utilizes its cooling potential while reducing the total quantity of water needed. The vaporized water mixes more uniformly with the fuel-air mixture, enhancing the reduction of preignition and NOx formation per unit of water added.
3Quantity of substance
If direct water injection is used, then water consumption is reduced, but packaging space requirements increase
Solution Approach 1:
The patent integrates the water storage reservoir, vaporizer assembly, and injection nozzle into a single compact packaging unit. The vaporizer is positioned within or adjacent to the injector housing, allowing water to be stored, heated, and injected through a consolidated arrangement. This merging of functions into one packaging unit reduces the overall volume required compared to separate water injection systems while maintaining low water consumption through direct injection.
4Ease of manufacture
If water is injected at low pressure, then packaging is simpler, but atomization effectiveness decreases
Solution Approach 1:
The patent uses a vaporizer assembly that changes water from liquid to vapor phase, eliminating the need for high-pressure injection to achieve atomization. The vaporization process itself creates the fine dispersion needed for effective mixing with the fuel-air mixture. This parameter change from liquid to vapor state allows for simpler packaging without compromising atomization effectiveness, as the phase transition naturally provides the necessary dispersion.
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
Enables efficient atomization of water at moderate pressures, reducing preignition and NOx formation, minimizing packaging requirements, and lowering water consumption and storage needs, while maintaining high compression ratios and specific outputs.
Implementation Method 1
a vaporizer assembly which is configured to vaporise the liquid water received from the water reservoir
Implementation Method 2
water has a very high latent heat of vaporisation (2200 kJ/kg). If the energy required to vaporise the liquid water is supplied by the intake charge, then the resultant temperature reduction of the charge reduces the propensity for preignition, detonation, and NOx formation
Data Source
AI summary
An injection device for injecting a combined water/gaseous fuel mixture into a combustion space of an engine. The injection device comprises: a first inlet for receiving a supply of water into a water chamber; a second inlet for receiving a supply of gaseous fuel into a flow passage; a mixing device comprising a valve assembly which is configured to control the flow of water between the water chamber and the flow passage so as to establish a combined gaseous fuel/water mixture within the flow passage; and an injection nozzle including a valve needle which is operable to control the delivery of the combined gaseous fuel/water mixture from the flow passage into the combustion space. The disclosure also extends to a fuel injection system.