Fuel Injector Pressure Measurement via Flow-Restricting Orifice
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Solution Overview
Problem
Existing fuel systems for internal combustion engines face challenges in maintaining stable and representative fuel pressure downstream of the fuel rail, leading to stiff pressure control and inadequate pressure measurement for feedback control, particularly due to the closed boundary at the downstream end of the fuel rail and insufficient pressure measurement upstream of the fuel injectors.
Innovation Solution
A fluid injection system comprising a fluid injector assembly, a fluid conditioning module with a pressure measurement port and a flow-restricting orifice, a pressure sensor, and a controller that adjusts the fluid flowrate based on pressure signals to maintain stable fuel pressure, decoupling the operation of the fluid conditioning module from engine speed and eliminating the need for mechanical pressure regulators.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Stability of the object's composition
If a closed or deadheaded boundary is used at the downstream end of the fuel rail, then pressure control becomes stiffer and more controllable, but the system becomes less adaptable and the pressure measurement is not representative of downstream injector pressure
Solution Approach 1:
A separate pressure measurement line with a flow-restricting orifice is introduced as an intermediary between the fuel rail and the pressure sensor. This measurement line is distinct from the main fuel delivery path, allowing accurate pressure sensing without interfering with the fuel rail's closed boundary configuration. The orifice creates a controlled flow that provides a representative pressure signal for feedback control.
Solution Approach 2:
The fuel system is segmented into separate functional paths: the main fuel delivery path with the closed boundary for stability, and a separate pressure measurement path with the orifice for accurate sensing. This segmentation allows each path to be optimized independently - the delivery path for pressure control stability and the measurement path for accurate feedback.
2Stability of the object's composition
If the fluid flow rate leaving the pump must precisely match the sum of fluid flow rates leaving the fuel injectors, then pressure control is achieved, but the system becomes overly stiff and sensitive to variations
Solution Approach 1:
The flow-restricting orifice in the pressure measurement line acts as a mediator that decouples the pressure sensing function from the main fuel flow. This allows the pressure control system to operate with less stiffness by providing accurate pressure feedback without requiring precise matching of pump output to injector demand.
Solution Approach 2:
A feedback control system using the pressure sensor and orifice measurement line is implemented to regulate fuel pressure. The feedback mechanism allows for dynamic adjustment of pump operation based on actual pressure conditions, reducing system stiffness while maintaining precise pressure control.
3Measurement precision
If pressure is measured within the fuel rail or upstream of the fuel rail, then pressure feedback control can be implemented, but the pressure measurement is not sufficiently representative of pressure supplying downstream injectors
Solution Approach 1:
A dedicated pressure measurement line with a flow-restricting orifice is introduced as an intermediary element that taps into the fuel rail pressure. This orifice creates a controlled flow that preserves the downstream pressure characteristics, providing an accurate representation of injector supply pressure to the sensor without requiring direct measurement at the injector location.
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 solution achieves more stable and repeatable fuel pressure control, reducing variance and improving engine performance, reliability, and fuel efficiency while allowing for smaller, cost-effective pump elements and improved filtration performance, enhancing engine operability and emissions control.
Implementation Method 1
an injector assembly outlet conduit fluidly coupled to an outlet port of the fluid injector assembly and disposed downstream of the fluid injector assembly along a direction of fluid flow through the fluid injector assembly, the injector assembly outlet conduit defining a pressure measurement port and a flow-restricting orifice, the pressure measurement port being disposed upstream of the flow-restricting orifice along the direction of fluid flow through the fluid injector assembly
Implementation Method 2
a pressure sensor fluidly coupled to the pressure measurement port; and a controller operatively coupled to the fluid conditioning module and the pressure sensor
Implementation Method 3
The controller is configured to adjust a flowrate of a fluid through the injector assembly inlet conduit based on a pressure signal from the pressure sensor
Data Source
AI summary
A fluid injection system includes a fluid injector assembly; a fluid conditioning module having an outlet port that is fluidly coupled to an inlet port of the fluid injector assembly; an injector assembly outlet conduit fluidly coupled to an outlet port of the fluid injector assembly and disposed downstream of the fluid injector assembly, the injector assembly outlet conduit defining a pressure measurement port and a flow-restricting orifice, the pressure measurement port being disposed upstream of the flow-restricting orifice along the direction of fluid flow through the fluid injector assembly; a pressure sensor fluidly coupled to the pressure measurement port; and a controller operatively coupled to the fluid conditioning module and the pressure sensor. The controller is configured to adjust a flowrate of a fluid through the injector assembly inlet conduit based on a pressure signal from the pressure sensor.