Fuel Injection Valve Needle Grooving for Flow Rate Control
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fuel injection systems for internal combustion piston engines face challenges in achieving reliable and stable fuel injection due to limitations in flow rate control and pressure management, particularly in common rail systems where the separation of pressure and timing control can lead to inefficiencies.
Innovation Solution
The fuel injection valve unit incorporates a fuel injection valve needle with a cylindrical support section and grooving that extends at an angle, allowing for controlled flow communication between the fuel space and control space, with a control valve managing the flow connection to a discharge channel, and a method of operating that utilizes pressurized fuel to balance forces and adjust the needle's position for precise injection control.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a conventional pressure controlled fuel injection system is used, then the fuel pressure is used for opening the injection needle, but the flow rate control is limited and rate shaping is difficult to achieve
Solution Approach 1:
The fuel injection system is segmented into two independent control functions: a first control valve for timing control and a second control valve for rate shaping control. This segmentation allows each valve to be optimized for its specific function, enabling reliable injection opening while providing versatile flow rate control capability.
Solution Approach 2:
A control line is introduced as an intermediary element connecting the second control valve to the control volume of the needle valve. This intermediary allows the second control valve to modulate the control pressure and thereby control the fuel injection rate without directly affecting the injection timing mechanism.
2Ease of operation
If a common rail fuel injection system is used, then pressure generation and timing control are separated, but inefficiencies arise in flow rate management
Solution Approach 1:
The system dynamically adjusts the control pressure through the second control valve during the injection event. This dynamic control allows the system to optimize both the timing (via first control valve) and the instantaneous flow rate (via second control valve), improving overall injection efficiency while maintaining ease of timing control.
Solution Approach 2:
The second control valve changes the control pressure parameter during the injection event to achieve rate shaping. By modulating the control pressure, the system can vary the needle valve opening degree and thereby control the fuel injection rate, improving productivity without compromising timing control.
3Measurement precision
If an injection control valve is positioned along a drain circuit to control drain flow, then precise needle valve movement is achieved, but the device complexity increases
Solution Approach 1:
The second control valve is designed to serve multiple functions: it controls the drain flow from the control volume, modulates the control pressure for rate shaping, and works in coordination with the first control valve for timing control. This multi-functionality reduces the need for additional specialized components, thereby limiting the increase in device complexity.
4Reliability
If a spill circuit is used to spill a portion of fuel to produce time varying flow rate change, then rate shaping is achieved, but fuel loss increases
Solution Approach 1:
Instead of spilling fuel directly, the system uses a second control valve as an intermediary to modulate the control pressure in the control volume. This indirect control mechanism achieves rate shaping by regulating the fuel flow through the needle valve without spilling excess fuel, thereby maintaining reliable rate control while minimizing fuel 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
This design enhances fuel injection reliability and stability by allowing for precise control of the injection rate and flow rate shaping, improving the overall performance of the fuel injection process.
Implementation Method 1
Fuel from the fuel space is led to the control space via the grooving. The flow path via the grooving is longer than a direct length of the contact area between the support section and the valve needle in the direction of the center axis of the valve needle.
Implementation Method 2
a flow path via the grooving is longer than the direct length of the contact area between the cylindrical support section and the valve needle in the direction of the center axis of the valve needle
Data Source
Figure 1
Figure 2
Figure 3
AI summary
Invention relates to fuel injection valve unit (1) for an internal combustion piston engine, comprising a fuel inlet (9) connectable to a common rail system (40) of the internal combustion piston engine for feeding pressurized fuel into the valve unit (1); at least one fuel injection opening (8) arranged at an end of the valve unit (1) for controllably injecting fuel; a fuel space (6) with which the fuel inlet (9) is in flow communication; a control space (7) with which the fuel inlet (9) is flow communication; a control valve (5) arranged in connection with the control space (7), which control valve (5) is arranged to open or close a flow connection from the control space (7) to a discharge channel (10); a fuel injection valve needle (2,22) comprising a first end (3) and a second end (4), in which the first end of fuel injection valve needle (2,22) is arranged to open or close a flow communication between the fuel space (6) and the at least one fuel injection opening (8), and in which the second end (4) of the fuel injection valve needle (2,22) is arranged to extend into the control space (7); the fuel injection valve needle (2,22) is partially circumscribed by a cylindrical support section (12) arranged between the fuel space (6) and the control space (7) and through which the valve needle (2,22) is arranged to extend in supported manner into the control space (7); and wherein a contact area (14) between the cylindrical support section (12) and the valve needle (2,22) is provided with a grooving (13) arranged at least partially at an angle with the center axis (A) of the valve needle (2,22).