Fuel Injector Solenoid Actuator Segmentation
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Solution Overview
Problem
Existing common rail fuel injectors face challenges in reducing costs while improving performance and enabling mass production while maintaining consistent results, particularly in controlling fuel injection effectively.
Innovation Solution
The fuel injector design includes a solenoid actuator with a movable armature and stator assembly, a check valve member, and a control valve member that move between defined positions to control fluid flow, incorporating a push pin and seat configuration with specific geometric features to facilitate reduced part count, self-centering, and consistent air gap dimensions for improved sealing and performance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If traditional solenoid actuator designs are used with direct operated check, then fuel injection control is achieved, but manufacturing costs are high and mass production consistency is difficult
Solution Approach 1:
The solenoid actuator is segmented into distinct functional components: armature, pole piece, stop pin, push pin, and control valve member. Each component has a specific function and can be manufactured independently with standard tolerances, then assembled. This segmentation allows for easier manufacturing and quality control while maintaining reliable fuel injection control through the coordinated action of these standardized parts.
Solution Approach 2:
The push pin acts as an intermediary component between the armature and the control valve member. It transfers motion from the armature to the control valve member while providing mechanical advantage and ensuring positive engagement. This intermediary mechanism simplifies the overall design by decoupling the electromagnetic actuation from the valve control, enabling mass production with consistent performance.
2Reliability
If air gap dimensions are not precisely controlled, then manufacturing is easier, but secondary injection events occur reducing performance
Solution Approach 1:
The stop pin is pre-positioned at a fixed location relative to the pole piece, establishing the air gap dimension before final assembly. The armature is designed with a predetermined stroke that stops against the stop pin, ensuring consistent air gap dimensions without requiring tight tolerances on all components. This preliminary positioning action ensures reliable injection performance while simplifying manufacturing.
Solution Approach 2:
The armature and stop pin are designed to self-align and self-position during assembly, with the armature stroke automatically limited by the stop pin. This self-service mechanism ensures consistent air gap dimensions without requiring complex adjustment procedures or high-precision machining, enabling mass production with consistent performance.
3Ease of manufacture
If control valve member is attached to push pin, then structural integrity is improved, but device complexity and manufacturing difficulty increase
Solution Approach 1:
The control valve member is extracted from the push pin assembly, making it an independent, unattached component. This allows the control valve member to be manufactured separately with optimized geometry and materials, then assembled into the injector body. The push pin and armature provide the necessary mechanical linkage without being physically attached to the control valve member, reducing overall device complexity while maintaining structural integrity through proper trapping and positioning.
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 reduces manufacturing costs, allows for mass production with consistent performance, and minimizes secondary injection events by ensuring precise air gap dimensions and self-centering, enhancing the overall efficiency and reliability of fuel injection.
Implementation Method 1
A solenoid actuator is disposed in the injector body, and includes an armature that moves with respect to a stator assembly
Implementation Method 2
A check valve member has a closing hydraulic surface exposed to fluid pressure in the control chamber, and is movable between a closed position blocking the nozzle outlet and an open position fluidly connecting the common rail inlet to the nozzle outlet
Data Source
AI summary
A common rail fuel injector includes a control valve member unattached to, but trapped between, a push pin and a seat of an injector body. The push pin has a head that includes a contact surface and a crown that includes a stop surface. An air gap surface of an armature is located between a top of the head and the stop surface of the crown when the contact surface of the push pin is in contact with the armature. The stop surface of the crown is located between an air gap plane of a stator assembly and the air gap surface of the armature. The push pin, the armature and the control valve member are movable among a rest configuration, an injection configuration, and an over travel configuration.