Fuel Injector Flow Rate Stabilization via Pressure Compensation
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Solution Overview
Problem
Existing fuel injectors have a significant dependence on fuel inlet pressure, which affects the fuel flow rate and lack the ability to vary the flow electronically or produce a desired spray pattern.
Innovation Solution
A fuel injector design featuring a reciprocating valve with a primary and secondary fuel chamber, a metering member to restrict fuel flow, and a spray-shaping surface to direct the fuel spray, allowing for reduced dependence on fuel inlet pressure and electronic control of fuel flow rate, while also shaping the fuel spray pattern.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional fuel injector design is used, then fuel injection function is achieved, but fuel flow rate is highly dependent on fuel inlet pressure
Solution Approach 1:
A pressure compensation chamber is introduced as an intermediary between the fuel inlet and the valve assembly. This chamber receives fuel through a restricted orifice, creating a pressure buffer that decouples the valve operation from direct fuel inlet pressure variations, thereby stabilizing fuel flow rate despite pressure fluctuations in the supply line
Solution Approach 2:
The patent changes the pressure parameter by creating a pressure compensation mechanism where fuel pressure is regulated through a restricted orifice into a compensation chamber. This transforms the uncontrolled high-pressure fuel supply into a controlled pressure environment that maintains stable flow characteristics regardless of inlet pressure variations
2Adaptability or versatility
If conventional fuel injector design is used, then fuel injection is achieved, but electronic control of fuel flow rate during injection is not possible
Solution Approach 1:
The patent implements a dynamic control mechanism where an electronically controllable valve (such as a PWM-controlled solenoid valve) replaces the conventional static needle valve. This allows the fuel flow rate to be dynamically adjusted during injection by varying the duty cycle or opening duration, enabling electronic control while maintaining a relatively simple overall structure
Solution Approach 2:
The conventional purely mechanical needle valve actuation is replaced with an electronically controllable valve mechanism. This substitution introduces electronic control capability (through PWM signals or electronic actuators) while maintaining the basic mechanical fuel injection function, thereby adding versatility without proportionally increasing complexity
3Shape
If conventional fuel injector design is used, then fuel delivery is achieved, but desired spray pattern cannot be produced
Solution Approach 1:
The patent applies local quality modification by incorporating spray-shaping surfaces or contours at specific locations within the injector body, particularly at the fuel outlet and within the combustion chamber interface. These localized geometric features (such as angled surfaces, recesses, or specific orifice shapes) direct and shape the fuel spray into desired patterns without requiring complete redesign of the entire injector structure
Solution Approach 2:
The patent utilizes dimensional modification by introducing spray-shaping surfaces that redirect fuel flow from a simple axial outlet into multi-directional spray patterns. By adding geometric features that deflect fuel at various angles, the system transforms a single-dimensional fuel delivery into a multi-dimensional spray distribution, achieving desired spray shapes through geometric manipulation rather than additional complex mechanisms
Data Source
AI summary
A fuel injector body has a fuel chamber and a valve seat around a fuel outlet. A valve body is positioned at the valve seat and a valve stem extends through the fuel outlet and fuel chamber. Engagement (disengagement) of valve body and valve seat closes (opens) the injector. The fuel chamber can comprise primary and secondary chambers connected by a valve passage and a metering member that restricts fuel flow between the chambers, thereby providing a flow-dependent closing force that reduces the dependence of fuel flow through the injector on fuel inlet pressure and that makes that flow dependent on an injector actuating force. The injector body or the valve body can comprise a spray-shaping surface arranged at least partly around the valve seat, which spray-shaping surface is arranged to direct a spray of fuel flowing through the fuel outlet.