Crankcase Deck Clearances for Large Engine Connecting Rod Assembly
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Solution Overview
Problem
Large internal combustion engines face challenges in assembly due to the large connecting rod eye, which requires auxiliary equipment and complicates the removal and installation process, especially with high cylinder pressure levels and increased dimensions, leading to increased effort and material costs.
Innovation Solution
The design includes clearances in the upper and lower decks of the crankcase that allow the connecting rod to be installed from above, eliminating the need to remove the crankshaft, and providing space for easy assembly and disassembly, with optional symmetrical clearances to prevent jamming and facilitate alignment.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Strength
If the crankshaft journals are enlarged to handle high cylinder pressure, then the connecting rod eye diameter increases, but the connecting rod can no longer be easily mounted and dismounted through the locating bore of the cylinder liner
Solution Approach 1:
The crankcase is divided into upper and lower decks with separate openings, allowing the connecting rod to be installed through the upper deck opening rather than through the cylinder liner locating bore. This segmentation of the installation path resolves the contradiction by providing an alternative access route that accommodates both the enlarged connecting rod eye and the cylinder liner positioning requirements.
2Ease of operation
If assembly from below is used, then the connecting rod can be mounted, but the crankshaft must be removed to replace the connecting rod, resulting in considerable additional work
Solution Approach 1:
The upper deck opening is designed in advance to allow connecting rod installation before crankshaft installation. This preliminary action enables the connecting rod to be positioned and prepared for crankshaft assembly, eliminating the need to remove the crankshaft later for connecting rod replacement and simplifying maintenance procedures.
Data Source
AI summary
The invention relates to a large internal combustion engine (1) with a crankcase (4), with a crankshaft (11) which is mounted rotatably in said crankcase (4), and with a crankshaft journal (10) on which a connecting rod (9) is pivotably arranged, wherein the crankcase (4) has an upper deck (O) and a lower deck (U) with in each case one opening for the cylinder liner (6), in which opening said cylinder liner (6) is arranged, and wherein the connecting rod (9) has an extent width (A) which is greater than the external diameter (a) of the cylinder liner (6). The problem addressed is that of specifying an improved large internal combustion engine. According to the invention, this is solved by virtue of the fact that the upper deck (O) and/or the lower deck (L′) have/has at least one clearance (FO, FU) for the installation of the connecting rod (9), and that the recess which is produced along the external diameter (a) of the cylinder liner (6) opens up at least an extent width (A) of the connecting rod (9) and has a breadth (W) which corresponds at least to a width (b) of the connecting rod (9). Moreover, the invention relates to an associated method for the assembly of the large internal combustion engine (1).