Fuel Injector Spacer-Ring Tolerance Compensation
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Solution Overview
Problem
The precise coupling of fuel injectors to cylinder heads in combustion engines is challenging due to tolerance variations and material compatibility issues, leading to potential damage and assembly complexities.
Innovation Solution
A fuel injector design featuring a spacer-ring and a fixing device with a discoidal and conic portion, allowing planar and rotational movements, made from stainless steel to ensure reliable coupling and tolerance compensation, while preventing chemical bonding with the cylinder head material.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the fuel injector is rigidly fixed to the cylinder head, then the coupling is simple, but the tolerance variations cause damage and unreliable operation
Solution Approach 1:
The patent applies the dynamics principle by introducing a spacer-ring that allows planar and rotational movements between the fuel injector and cylinder head. This dynamic coupling mechanism compensates for tolerance variations and thermal expansion, transforming the rigid fixed connection into a flexible adaptive connection that maintains reliability under varying operating conditions.
Solution Approach 2:
The spacer-ring acts as an intermediary element between the fuel injector and cylinder head. It mediates the coupling by absorbing dimensional discrepancies and thermal effects, preventing direct stress transmission that would cause damage, while maintaining the functional connection through its planar and rotational movement capabilities.
2Manufacturing precision
If the fuel injector is allowed to move freely, then tolerance variations are compensated, but the coupling becomes unstable and imprecise
Solution Approach 1:
The spacer-ring provides controlled dynamic movement within specific limits, allowing planar and rotational adjustments to compensate for tolerances while maintaining stable coupling. The dynamic capability is constrained by the physical boundaries of the spacer-ring design, ensuring precision is maintained within acceptable movement ranges.
Solution Approach 2:
The system utilizes parameter changes through thermal expansion and contraction of the spacer-ring material. As temperature varies during engine operation, the spacer-ring dimensions change to accommodate dimensional variations in the fuel injector and cylinder head, maintaining precise coupling without requiring complex active adjustment mechanisms.
3Strength
If different materials are used for the fuel injector and cylinder head, then material compatibility is improved, but chemical bonding issues arise
Solution Approach 1:
The spacer-ring serves as a material intermediary between the fuel injector and cylinder head. By placing this intermediate component between the two different materials, the patent prevents direct chemical bonding or reactions between incompatible materials, while still transmitting mechanical loads and maintaining coupling strength through the spacer-ring's structural integrity.
Data Source
Figure 1
Figure 2A~2B
Figure 3~5
AI summary
Fuel injector (18) of a combustion engine (22) comprising a fuel injector housing (26) and a spacer-ring (35). The injector housing (26) is applicable to be mounted in a cylinder head (14) of the combustion engine (22). The spacer-ring (35) being applicable to allow planar and rotational movements of the fuel injector (18) within the cylinder head (14) of the combustion engine (22). The fuel injector (18) further comprises a fixing device (50). The fixing device (50) comprises a discoidal portion (52) with a central opening and a conic portion (51). The discoidal portion (52) comprises an inner diameter (54), representing the diameter of the central opening, and an outer diameter (55). The outer diameter (55) is larger than the inner diameter (54), whereas the inner diameter (54) is larger than the diameter of the injector housing (26), where the fixing device (50) is arranged. The discoidal portion (52) comprises an upper planar surface (60) and a bottom planar surface (61). The bottom planar surface (61) is in contact with the cylinder head (14). The upper planar surface (60) is in contact with the spacer-ring (35), if the fuel injector (18) is mounted in the cylinder head (14). The conic portion (51) comprises a first diameter (56) and a second diameter (53). The first diameter (56) is larger than the second diameter (53) and is in the range of the inner diameter (54) of the discoidal portion (52). The second diameter (53) being larger than the diameter of the injector housing (26), where the fixing device (50) is arranged. The end of the first diameter (56) of the conic portion (51) is rigidly coupled to the discoidal portion (52).