Fuel Injector Dual Actuator Decoupling Strategy
Find Innovative SolutionsGenerate Solutions
Solution Overview
Problem
Existing fuel injectors for internal combustion engines face inefficiencies due to the need for powerful solenoid actuators to overcome the initial closing force of the valve needle, leading to over-specification and increased mass, which slows operation and results in poor efficiency and parasitic losses in hydraulic servo mechanisms, while direct-acting piezoelectric actuators waste energy by applying excessive force throughout the lifting movement.
Innovation Solution
A fuel injector design featuring first and second actuator arrangements, where the first actuator provides an initial lifting force and decouples from the valve needle, allowing the second actuator to assist in reaching full lift position, optimizing each actuator's function and reducing the overall size and energy consumption.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If a powerful solenoid actuator is used to lift the valve needle initially, then the valve needle can be opened, but the solenoid becomes significantly over-specified for the remainder of the lifting movement, resulting in poor efficiency
Solution Approach 1:
The lifting movement of the valve needle is divided into two phases: initial lifting (overcoming closing force) and continued movement (maintaining lift). Two separate solenoid actuators are assigned to each phase, allowing each actuator to be optimally sized for its specific function rather than one actuator being over-specified for the entire range.
Solution Approach 2:
The system transitions from a static configuration (one solenoid for entire stroke) to a dynamic configuration where the first solenoid decouples from the valve needle after initial lifting. This dynamic reconfiguration allows the system to adapt the applied force to the instantaneous needs of the valve needle movement.
2Force
If a solenoid actuator with large armature area is provided to achieve high-force actuation, then the retracting force is sufficient, but the armature volume and mass increase, making the valve needle heavy and slowing operation
Solution Approach 1:
The total mass requirement is segmented between two smaller armatures rather than one large armature. Each armature only needs to provide force for a portion of the lifting stroke, allowing both to be smaller and lighter individually, thus reducing the total moving mass and improving response speed.
Solution Approach 2:
The first solenoid actuator applies force only for the initial portion of the lifting movement (partial action), then decouples. This allows the first armature to be smaller than would be required if it had to provide force for the entire stroke, reducing its mass and the overall system inertia.
3Stress or pressure
If fuel pressure in the system increases, then injection performance improves, but more powerful solenoids are required, and direct-acting configuration becomes impractical
Solution Approach 1:
The actuation system is segmented into two solenoids working in sequence rather than one large solenoid. This segmentation allows each solenoid to be of moderate size, making the system practical for high-pressure applications where a single powerful solenoid would be excessively large and complex.
Solution Approach 2:
The system uses dynamic decoupling of the first solenoid after initial lifting, creating a two-stage actuation process. This dynamic approach allows the system to handle high fuel pressures effectively while maintaining a practical and manageable actuator configuration.
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 configuration enables a compact, efficient fuel injector with improved response speed and reduced energy waste, as the first actuator provides only the necessary initial force and the second actuator handles the full lift, matching the required force more closely and minimizing unnecessary energy expenditure.
Implementation Method 1
a solenoid actuator that is powerful enough to lift the valve needle initially
Implementation Method 2
Once valve needle movement has been initiated and fuel is able to flow underneath the tip of the valve needle, a reduced force is sufficient to cause continued movement of the valve needle towards its full lift position
Data Source
Figure 1
Figure 2
Figure 3
AI summary
A fuel injector (100) for use in an internal combustion engine, the fuel injector (100) comprising an injection nozzle having a nozzle body (120) provided with a nozzle bore (130), a valve needle (134) being received within the nozzle bore (130) and engageable with a seat region (137) to control fuel delivery through at least one nozzle outlet (126) and first and second actuator arrangements (150, 152), at least the first actuator arrangement (150, 152) being operable to apply an opening force to the valve needle (134) thereby to cause an opening movement of the valve needle (134), wherein the first actuator arrangement (150) is configured to decouple from the valve needle (134) in response to said opening movement.