Fuel Injection Valve Control Chamber Switching
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Current fuel injection valves for internal combustion engines are inefficient in terms of hydraulic efficiency during intermittent fuel injection, with the nozzle needle opening and closing processes being slow, which affects the timing and frequency of fuel injection.
Innovation Solution
A fuel injection valve design featuring a housing with high-pressure and low-pressure chambers, a longitudinally movable nozzle needle, and a control valve system with a switching element, such as a ball, that temporarily interrupts the connection between control chambers to enhance the speed of nozzle needle operation, allowing for quicker opening and closing.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Speed
If a continuous connection is maintained between the two control chambers via a flow restrictor, then fuel can be continuously exchanged between the chambers, but the opening and closing speed of the nozzle needle is limited and hydraulic efficiency is reduced
Solution Approach 1:
The drain throttle is pre-positioned to connect the two control chambers before injection, allowing pressure equalization to occur in advance. When the pilot valve opens, the pressure difference is already established, enabling the nozzle needle to open faster without requiring continuous fuel exchange through the flow restrictor during the injection event.
Solution Approach 2:
The patent removes the flow restrictor component entirely from the system. Instead of using a flow restrictor to control fuel exchange between control chambers, the design uses a drain throttle that can be selectively opened or closed by the pilot valve, eliminating the hydraulic resistance that limited needle response speed.
2Productivity
If a flow restrictor is used to connect the two control chambers, then fuel exchange between chambers is enabled, but the injection interval time is increased and injection frequency is reduced
Solution Approach 1:
The drain throttle is opened before injection to pre-equalize pressure between control chambers, so that when injection occurs, the system is already prepared for rapid needle response. This eliminates the time delay that would otherwise be required for pressure equalization during each injection cycle, enabling shorter injection intervals and higher injection frequency.
Solution Approach 2:
The system transitions from a static flow restrictor configuration to a dynamic drain throttle controlled by the pilot valve. The drain throttle can be rapidly opened and closed based on injection timing requirements, allowing the system to adapt its fuel exchange rate dynamically rather than being constrained by a fixed flow restrictor geometry.
3Duration of action of moving object
If the control chamber is filled quickly via an inlet throttle after pilot valve closure, then the nozzle needle closes faster, but the overall injection timing precision is compromised
Solution Approach 1:
The drain throttle is opened in advance to equalize pressure between control chambers before injection, creating a known initial state. This preliminary action ensures that when the pilot valve closes and the inlet throttle fills the control chamber, the timing is predictable and precise, as the starting pressure conditions are already established.
Solution Approach 2:
The drain throttle acts as an intermediary mechanism that mediates between the two control chambers, allowing pressure equalization to occur in a controlled manner before injection. This intermediary function separates the pressure equalization process from the injection timing process, allowing each to be optimized independently without compromising the other.
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 improves hydraulic efficiency, shortens the interval between fuel injections, and reduces fuel consumption by enabling faster injection processes and more precise control over the injection timing, leading to improved combustion and reduced fuel waste.
Implementation Method 1
The movement of the nozzle needle, and thus the start and end of each injection, is hydraulically controlled. This is achieved using a control chamber filled with fuel. The high-pressure fuel exerts pressure on the nozzle needle, forcing it against a nozzle seat by means of the resulting hydraulic closing force. This pressure is further increased by a needle closing spring, which already exerts pressure on the nozzle needle even before hydraulic pressure is applied.
Implementation Method 2
The high-pressure fuel exerts pressure on the nozzle needle, forcing it against a nozzle seat by means of the resulting hydraulic closing force.
Implementation Method 3
A control valve can reduce the pressure exerted on the upper side of the nozzle needle, causing it to lift from the nozzle seat into its open position and thus releasing the injection opening.
Data Source
Figure 1
Figure 2a~2b
Figure 3a~3c
AI summary
The invention relates to a fuel injection valve for the intermittent injection of fuel into the combustion chamber of an internal combustion engine, comprising a housing with a high-pressure chamber and a low-pressure chamber. The fuel injection valve also includes a control chamber, which is divided into a first and a second control chamber by means of a control valve. The control valve, in turn, has a valve guide and a valve insert, wherein a flow restrictor is arranged in the valve guide, connecting the first control chamber to the second control chamber. According to the invention, the connection formed by the flow restrictor between the first control chamber and the second control chamber can be selectively and temporarily interrupted.