Fuel Injector Variable Inlet Throttle for Gaseous Fuel
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Solution Overview
Problem
High injection pressures in fuel injectors for gaseous fuels lead to excessive injection rates during partial engine load, causing noise and emissions issues, and existing gas pressure regulation is slow and inefficient, resulting in wasted fuel and environmental concerns.
Innovation Solution
A fuel injector design with a nozzle needle and bolt system that adjusts the inlet throttle's cross-section dynamically, allowing for controlled hydraulic pressure medium flow, enabling adjustable injection rates independent of gas pressure, using a rotatable or radially movable bolt within a cylinder to manage the flow and maintain constant gas pressure.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Use of energy by moving object
If high injection pressures are used to meet full load requirements, then fuel consumption is optimized, but injection rates become too high during partial load operation causing noise and emissions
Solution Approach 1:
The inlet throttle cross-section is made variable through a bolt that can be positioned at different locations within the inlet channel. This allows the throttle area to be dynamically adjusted based on operating conditions, enabling high injection rates at full load while reducing injection rates at partial load, thus resolving the contradiction between fuel efficiency and noise/emissions
Solution Approach 2:
The injection rate is controlled by changing the geometric parameter of the inlet throttle cross-section. By varying the bolt position, the throttle area parameter is adjusted, which directly controls the hydraulic fluid flow rate and consequently the needle opening speed and injection rate, allowing optimization for different operating points
2Object-generated harmful factors
If gas pressure is reduced to lower injection rates, then noise and emissions are reduced, but injection pressure is insufficient for full load operation
Solution Approach 1:
A hydraulic fluid is introduced as an intermediary medium to control the needle opening process. The hydraulic fluid flow through the variable inlet throttle acts as a mediator between the gas pressure system and the needle motion, allowing independent control of injection rate without changing gas pressure, thus resolving the contradiction between reducing harmful factors and maintaining injection power
3Adaptability or versatility
If a pressure regulating valve is installed on the gas storage tank to control injection rates, then injection rates can be adjusted, but control is slow due to gas compressibility and large quantities of control gas are lost
Solution Approach 1:
The invention switches from gas-based pressure control to hydraulic control. By using a liquid hydraulic fluid instead of compressible gas, the system achieves rapid and precise control of the inlet throttle opening. The hydraulic fluid is supplied under pressure through a pump and controlled by a valve, enabling fast response times and eliminating the time delays associated with gas compression and expansion
Solution Approach 2:
The mechanical/gas-based pressure regulation system is replaced with a hydraulic control system. The bolt position control mechanism (via cylinder and piston) substitutes for slow gas pressure regulation, providing precise and rapid control of the inlet throttle cross-section without the drawbacks of gas compressibility
4Adaptability or versatility
If a pressure regulating valve is used to control injection rates, then injection rates can be adjusted, but control gas cannot be returned to the gas tank or used for combustion due to low pressure level
Solution Approach 1:
The invention replaces gas-based control with hydraulic control using an incompressible liquid fluid. The hydraulic fluid circulates in a closed loop system between the pump, the inlet throttle control, and the reservoir. Since hydraulic fluid is not consumed in the control process and can be fully recovered and reused, there is no loss of substance, resolving the contradiction between controllability and substance loss
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 dynamic adjustment of injection rates based on operating conditions without altering gas pressure, reducing noise and emissions, and optimizing fuel consumption by maintaining high needle dynamics at full load.
Implementation Method 1
a movable nozzle needle (2) for opening and closing at least one injection orifice (16), the nozzle needle (2) defining a control chamber (3) which can be pressurized with a hydraulic pressure medium, preferably liquid fuel
Implementation Method 2
a bolt (6) received in an inlet channel (5), forming an annular gap (13) that serves as an inlet throttle (4), the position of which is variable with respect to a longitudinal axis (10) of the inlet channel (5), so that the throttle cross-section (Az) of the inlet throttle (4) is annular or crescent-shaped
Data Source
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AI summary
The invention relates to a fuel injector (1) for the injection of gaseous fuels into a combustion chamber of an internal combustion engine, comprising at least one nozzle needle (2) which can move in a reciprocating manner and which serves for opening up and closing at least one injection opening, wherein the nozzle needle (2) delimits a control chamber (3) which can be charged with a hydraulic pressure medium, preferably with liquid fuel, via an inflow throttle (4) which is configured within an inflow duct (5). According to the invention, a pin (6) is received in the inflow duct (5) with the configuration of an annular gap which serves as an inflow throttle (4), the position of which pin (6) in relation to a longitudinal axis (10) of the inflow duct (5) can be changed, with the result that the throttle cross section of the inflow throttle (4) is annular or crescent-shaped. Furthermore, the invention relates to a method for operating a fuel injector (1).