Multi-orifice Fuel Injection Nozzle for Combustion Chamber Wall Wetting
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Solution Overview
Problem
Conventional fuel injection systems in gasoline engines with direct fuel injection often result in undesirable wetting of combustion chamber walls and increased pollutant emissions due to uneven fuel distribution and air mass flow, particularly in supercharged engines with central injection nozzles.
Innovation Solution
The fuel injection system is designed with injection nozzles having at least two orifices, where a smaller quantity of fuel is injected on the exhaust side compared to the intake side, and an additional quantity is injected between the intake and exhaust sides, optimizing fuel distribution to minimize wall wetting and emissions. The nozzles are configured to direct fuel away from walls, with a conical spray geometry and specific opening diameters and orientations to achieve low-emission operation.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Manufacturing precision
If fuel is injected with high pressure (up to 20 MPa) through a central injection nozzle to achieve good atomization, then fuel distribution is improved, but wetting of combustion chamber walls and increased pollutant emissions occur
Solution Approach 1:
The injection nozzle is divided into multiple injection orifices (at least three) arranged in different directions. Each orifice directs fuel spray toward different regions of the combustion chamber, segmenting the fuel distribution to avoid concentrated spraying that causes wall wetting while maintaining good atomization through multiple targeted injection points.
Solution Approach 2:
Different injection orifices are designed with different orientations and positions to create locally optimized fuel distribution. The orifices are arranged to direct spray toward the center and away from walls, with at least one orifice angled to prevent wall contact, providing locally adapted fuel injection characteristics for different combustion chamber regions.
2Device complexity
If a central injection nozzle is used in supercharged engines with tumble flow, then fuel injection is simplified, but air mass motion guides fuel to the exhaust side causing increased fuel concentration and wall wetting
Solution Approach 1:
The injection nozzle employs asymmetric orifice arrangement where at least one injection orifice is oriented at an angle to direct fuel spray away from the exhaust side toward the center or intake side of the combustion chamber. This asymmetric configuration counteracts the tumble flow effect that would otherwise concentrate fuel on the exhaust side, preventing localized fuel accumulation and wall wetting while maintaining a relatively simple central nozzle structure.
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 design significantly reduces undesirable wetting of combustion chamber walls and associated pollutant emissions, ensuring efficient and low-emission combustion by optimizing fuel distribution and spray geometry, potentially eliminating wall contact and emissions entirely.
Implementation Method 1
The injection nozzle has injection orifices which are designed and oriented in such a way that a first quantity of fuel is injected into the intake side, a second quantity of fuel injected is into the exhaust side, and a third quantity of fuel which is about equal to the first quantity and greater than the second quantity is injected into a boundary area between the intake and the exhaust sides
Data Source
AI summary
In a fuel injection system of an internal combustion engine, having a combustion chamber with at least one intake valve at an intake side and with at least one exhaust valve at an exhaust side of the combustion chamber and a central injection nozzle for injecting fuel into the combustion chamber, the injection nozzle has injection orifices which are designed and oriented in such a way that a first quantity of fuel is injected into the intake side, a second quantity of fuel injected is into the exhaust side, and a third quantity of fuel which is about equal to the first quantity and greater than the second quantity is injected into a boundary area between the intake and the exhaust sides, providing for a low-emission operation of the internal combustion engine.