Dual Fuel Injector Cooling Channel and Leak Detection
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Solution Overview
Problem
Existing dual fuel injectors for internal combustion engines face issues such as fuel nozzle tip overheating leading to tar formation and needle sticking, inefficient use of space, lack of gas leak detection, and inadequate combustion pressure control, which can result in engine damage and safety hazards.
Innovation Solution
A single unit fuel injector with interconnected nozzles featuring a cooling channel and a combustion pressure sensor, where the micro-pilot injector operates at lower pressure than the main injector, and includes a gas leak detection system, allowing for efficient fuel delivery and leak detection, and improved combustion control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Temperature
If fuel is not circulated through cooling channels, then the injector structure is simpler, but the nozzle tip overheats and tar forms causing needle sticking
Solution Approach 1:
The injector is divided into functional segments with separate cooling channels for each nozzle type. The micro-pilot injector and main fuel injector each have dedicated cooling passages, allowing independent temperature control and fuel circulation paths. This segmentation enables effective cooling without requiring a completely redesigned injector structure.
Solution Approach 2:
The cooling fuel serves multiple functions simultaneously: it cools the nozzle tips to prevent overheating and tar formation, and it provides lubrication for the needle mechanisms. This multi-functionality reduces the need for separate cooling systems, thereby limiting the increase in structural complexity.
2Reliability
If space in the injector is not optimized, then the injector design is simpler, but there is no space for adding a combustion pressure sensor
Solution Approach 1:
The combustion pressure sensor is integrated into the injector assembly by mounting it on the injector body, combining two previously separate components (injector and sensor) into a single integrated unit. This merging allows combustion pressure monitoring without requiring additional external sensors, thereby improving reliability while limiting the increase in overall system complexity.
Solution Approach 2:
The sensor is mounted on the external surface of the injector body rather than requiring internal cavity space. This dimensional relocation allows the sensor to be positioned in available external space, avoiding interference with the internal nozzle and fuel passage geometry.
3Productivity
If micro-pilot injector opens at high pressure, then fuel injection is more efficient, but soot production and noise increase
Solution Approach 1:
The fuel injection process is divided into periodic stages: first the micro-pilot injector operates at lower pressure for initial combustion, then the main fuel injector activates at higher pressure for complete fuel delivery. This periodic, staged injection reduces sudden pressure spikes and associated harmful effects while maintaining overall injection efficiency.
Solution Approach 2:
The injection pressure parameter is changed over time through the two-stage process. The micro-pilot injector uses lower pressure (reducing soot and noise), followed by the main injector at higher pressure. This dynamic parameter change optimizes the balance between injection efficiency and harmful emissions.
4Reliability
If gas leak detection is not implemented, then the system is simpler, but safety hazards occur from undetected leaks
Solution Approach 1:
The system performs self-monitoring through the integrated combustion pressure sensor that continuously tracks pressure parameters during operation. Abnormal pressure patterns automatically indicate potential gas leaks or combustion issues, enabling the system to detect problems without requiring separate complex detection systems.
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 prevents fuel nozzle tip overheating, enhances combustion efficiency, reduces soot production and noise, and ensures safe operation by accurately controlling gas supply and detecting leaks, thereby minimizing engine damage and ensuring safety.
Implementation Method 1
the nozzles at the level of their nose are connected with each other by means of a cooling channel or duct, and wherein a pump (optionally a plunger or piston pump) by means of each activation (pump stroke of a plunger pump) pumps approximately the entire pump volume of fuel through the cooling channel and past the nozzles, and thereby cools parts that are most exposed to heat
Data Source
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AI summary
An assembly at least comprising a fuel injector for dual fuel operation of an internal combustion engine. The assembly includes a nozzle holder defining a fuel circuit and provided with a nose adapted in use to be in connection with a combustion space of an internal combustion engine, and first and second nozzles in communication with the fuel circuit in the nozzle holder for directly injecting liquid fuel into the combustion space of the internal combustion engine for ignition of a combustible mixture present in the combustion space. The first and second nozzles adjacent to the nose of the nozzle holder are interconnected by a cooling channel. At each actuation of a fuel pump upstream of the first and second nozzles, substantially a full volume of fuel pumped during actuation of the fuel pump is allowed to flow through the cooling channel and via the first and second nozzles, to provide cooling thereof. The assembly further comprises a spill valve in the fuel circuit. Opening and closing of the spill valve controls the amount of liquid fuel to be delivered to the first and second nozzles.