Chain Casing Solenoid Valve Mounting Rigidity
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Solution Overview
Problem
In internal combustion engines, the rigidity of the portion near the solenoid valve attachment portions is compromised due to increased gaps between fastening portions, leading to vibrations that affect the solenoid valves.
Innovation Solution
The design includes a chain casing with a bulging portion covering the variable valve timing mechanism, where the solenoid valves are positioned closer to the oil pan than the bulging portion. The solenoid valves have specific diameter portions arranged on either side of the intake and exhaust ports, and the solenoid valve attachment portions are integrated with the oil pump accommodation portion, with strategically arranged accommodation holes and fastening holes to enhance rigidity and reduce vibration loads.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of manufacture
If the gap between fastening portions is increased to avoid interference between casting pins, then the solenoid valve attachment portions can be properly formed, but the rigidity of the portion near the solenoid valve attachment portions decreases
Solution Approach 1:
The patent resolves the casting pin interference problem by changing the spatial arrangement from a linear gap increase to a three-dimensional configuration. The solenoid valve attachment portions are positioned at different heights (vertical dimension) and angular positions around the crankshaft, allowing casting pins to be arranged without interference while maintaining structural rigidity through optimal spatial distribution.
Solution Approach 2:
The patent employs asymmetric arrangement of the solenoid valve attachment portions around the crankshaft. Instead of symmetric placement that would require larger gaps, the attachment portions are positioned at different angular intervals and vertical levels, creating an asymmetric configuration that maximizes rigidity while minimizing the required gap between fastening portions.
2Reliability
If the rigidity of the oil pump accommodation portion is increased to suppress vibrations, then the solenoid valve stability improves, but the device complexity increases
Solution Approach 1:
The patent combines the oil pump accommodation portion with the chain casing into a single integrated structure. The oil pump is mounted within the chain casing itself, and the solenoid valve attachment portions are formed as integral parts of the chain casing. This merging eliminates the need for separate mounting structures and brackets, reducing overall device complexity while maintaining the rigidity needed to suppress vibrations and ensure solenoid valve stability.
Data Source
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AI summary
[Object] To provide an internal combustion engine capable of improving rigidity of a portion in the vicinity of a first solenoid valve attachment portion and a second solenoid valve attachment portion provided between adjacent cylinder head fastening portions of an oil pump accommodation portion of a chain casing and suppressing a load caused by a vibration of the oil pump accommodation portion from acting on a first solenoid valve and a second solenoid valve. [Solution] An axis 23R of an accommodation hole 23A of a first solenoid valve attachment portion 23 and an axis 24R of an accommodation hole 24A of a second solenoid valve attachment portion 24 are arranged at different positions in an EF direction. At least a part of the first solenoid valve attachment portion 23 and the second solenoid valve attachment portion 24 overlaps in an AB direction. Fastening holes 41A and 42A of cylinder head fastening portions 41 and 42 are formed outside a projection area obtained by projecting the accommodation hole 23A of the first solenoid valve attachment portion 23 toward the fastening holes 41A and 42A and outside a projection area obtained by projecting the accommodation hole 24A of the second solenoid valve attachment portion 24 toward the fastening holes 41A and 42A.