Fuel Injector Telescopic Valve Hydraulic Balancing
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Solution Overview
Problem
Prior art fuel injectors require a hydraulically balanced valve member to ensure effective operation, which can be costly and complex to achieve with existing coil and magnetic armature actuators.
Innovation Solution
A movable valve member with a telescopic design, comprising a piston and shutter member, and a disc flange with restricted orifices, which creates a pressure difference to balance hydraulic forces and allows for efficient opening and closing of the valve seat, facilitated by an electromagnet actuator.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a coil and magnetic armature actuator is used to open or close fuel injection holes, then the valve member can be actuated, but the valve member requires hydraulic balancing which increases device complexity and manufacturing cost
Solution Approach 1:
The valve member is segmented into a telescopic structure with an outer cylinder and an inner plunger that can move independently. This segmentation allows the inner plunger to be hydraulically balanced while the outer cylinder provides structural support, eliminating the need for complex hydraulic balancing of the entire valve member.
Solution Approach 2:
A balanced port is introduced as an intermediary hydraulic passage that connects the high-pressure fuel supply to the annular chamber surrounding the inner plunger. This intermediary port provides the balancing force needed to reduce the electromagnet's workload without requiring complex hydraulic balancing of the valve member itself.
2Force
If a telescopic valve member with inner plunger and outer cylinder is used, then hydraulic balancing is achieved reducing electromagnet effort, but device complexity increases
Solution Approach 1:
The valve member combines the inner plunger and outer cylinder into a single telescopic assembly where the inner plunger is received within the outer cylinder. This merging of components achieves hydraulic balancing while maintaining a compact structure that does not significantly increase overall device complexity.
Solution Approach 2:
The telescopic valve member utilizes hydraulic pressure from the high-pressure fuel supply to automatically balance the forces on the inner plunger. The balanced port introduces pressurized fuel to create an opposing force that reduces the net force required by the electromagnet, achieving force reduction through hydraulic principles rather than mechanical complexity.
3Force
If the inner plunger is made of telescopic parts with different diameters, then hydraulic balancing is achieved, but manufacturing precision requirements increase
Solution Approach 1:
The inner plunger features local quality variations with different diameter sections (first cylindrical part with larger diameter, second cylindrical part with smaller diameter). Each section serves a specific function: the larger diameter provides structural strength while the smaller diameter section interacts with the balanced port for hydraulic balancing. This localized differentiation achieves hydraulic balancing with manageable manufacturing tolerances.
Solution Approach 2:
The telescopic valve member is designed to be dynamically balanced during operation rather than statically balanced. The inner plunger moves freely within the outer cylinder, and the hydraulic balancing forces are dynamically adjusted based on operating conditions. This dynamic approach reduces the stringency of manufacturing precision requirements compared to a statically balanced design.
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
The solution provides a simple, economical, and hydraulically balanced fuel injector that efficiently opens and closes the valve seat with reduced effort from the electromagnet, ensuring effective fuel injection and minimizing leakage.
Implementation Method 1
Said flange further defines a first restricted orifice and a second restricted orifice both extending between the opposite faces of the flange and allowing pressurized fuel to pass at reduced speed from one side of the flange to the other in creating a pressure difference between the faces of the flange.
Implementation Method 2
The movable member further comprises a first spring compressed between the piston and the shutter member and permanently urging the piston and the shutter member towards an extension of the movable member.
Implementation Method 3
the injector itself being provided with a nozzle whose needle is directly opened or closed by an electromagnetic actuator coil
Data Source
Figure 1
Figure 2
Figure 3~5
AI summary
A mobile valve member (48) designed to be arranged in the nozzle body (30) of a fuel (F) injector (10), extends along a main axis (XI) and comprises a piston (50) formed of a male first cylinder (62) of effective diameter (DE) forming the top end of the mobile member (48) and of a second cylinder (64) provided with an internal cylindrical bore (68) of diameter (DE) and a shutoff member (52) comprising a male cylindrical shaft (84) of effective diameter (DE) which is a sliding fit in the internal bore (68), and of a member (88) extending as far as a pointed end provided with a mobile seat (56) and forming the bottom end of the mobile member (48). The mobile member (48) is hydraulically balanced and has a length between its top end and its bottom end that is variable because of the sliding of the cylindrical shaft (84) in the internal bore (68) of the piston.