Electromagnetic Fuel Injector Braking Device
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Solution Overview
Problem
Electromagnetic fuel injectors face challenges in maintaining dynamic performance at high fuel pressures due to increased hydraulic and magnetic inertia, leading to steep and irregular fuel injection ramps, which complicates precise control and increases pollution.
Innovation Solution
The design incorporates a hydraulic braking device coupled to the plunger, which dissipates more kinetic energy during the opening stroke of the needle, stabilizing the injection valve's opening and reducing the sudden force change, allowing for smoother operation and improved controllability.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Force
If the size of the electromagnet is increased to increase the magnetic attraction force, then the force generated by the electromagnet is improved, but the magnetic and mechanical inertia of the electromagnet increases, causing slower response and degraded dynamic performance
Solution Approach 1:
The patent divides the single large electromagnet into two smaller twin electromagnets. Each electromagnet has its own coil and magnetic pole, both acting on a common plunger. This segmentation provides the necessary magnetic force while keeping individual electromagnet sizes small, thus maintaining low inertia and fast response speed.
2Force
If higher performance materials are used to increase the power of the electromagnet, then the magnetic attraction force is improved, but the manufacturing cost increases considerably
Solution Approach 1:
Instead of using expensive high-performance materials in a single large electromagnet, the patent uses two smaller electromagnets with conventional materials. This segmentation approach achieves the required force output while using standard, cost-effective materials, making the solution economically viable for the automotive industry.
3Productivity
If the fuel feeding pressure is increased to improve fuel mixing and combustion, then the combustion performance is improved, but the hydraulic forces increase proportionally, requiring stronger closing springs and more powerful electromagnets
Solution Approach 1:
The twin electromagnet configuration provides the necessary force multiplication to overcome high hydraulic forces at elevated fuel pressures (50 MPa and above). The combined force from two electromagnets acting on a common plunger enables the system to maintain valve control under high pressure conditions while supporting improved fuel mixing and combustion performance.
4Speed
If the injection valve opens very quickly to respond to actuation, then the response time is improved, but the opening becomes violent with extremely fast needle movement, causing steep and irregular injection ramps that complicate control
Solution Approach 1:
The patent introduces a braking device that provides hydraulic damping during the needle opening stroke. This device creates resistance to the needle movement, cushioning the opening process and preventing violent opening. The braking force is designed to be active during opening but not during closing, thereby stabilizing the injection law and producing linear, uniform injection ramps while maintaining fast response capability.
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 solution enhances the dynamic performance of the fuel injector by maintaining high precision and accuracy in fuel injection, even at high pressures, while being cost-effective and simple to manufacture, with a linear and uniform injection law.
Implementation Method 1
a braking device of the hydraulic type, which is coupled to the feeding hole and hydraulically dissipates more kinetic energy when the needle moves towards the opening position
Implementation Method 2
an electromagnet which pushes the needle towards the opening position... The electromagnet includes a coil externally arranged in a fixed position about the tubular body, a movable plunger firmly connected to the needle and movably mounted inside the tubular body, and a fixed magnetic pole made of ferromagnetic material
Implementation Method 3
a closing spring, which tends to hold the needle in the closing position... The closing spring is arranged inside the central hole and is compressed between a perforated catch body driven into the central hole, and the plunger, so as to push the plunger (and, thus, the needle integral with the plunger) towards the closing position
Data Source
AI summary
The present invention relates to a fuel injector. The fuel injector is provided with an injection nozzle, an injection valve, and an electromagnetic actuator. The injection valve has a movable needle to adjust the flow of fuel through the injection nozzle. The electromagnetic actuator is adapted to move the needle between a closing position and an opening position of the injection valve and is provided with a movable plunger which is mechanically connected to the needle and has at least one feeding through hole for the passage of fuel towards the injection nozzle. The plunger is provided with a hydraulic type braking device, which is coupled to the feeding hole and hydraulically dissipates kinetic energy to slow down the opening stroke of the needle when the needle moves towards the opening position of the injection valve.