Cylinder Bore Cutouts for Engine Height Reduction
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Solution Overview
Problem
Existing internal combustion engines face challenges in reducing height without increasing the distance from the connecting rod connection part to the counter weight, which leads to increased bending forces at high speeds, making the design structurally undesirable.
Innovation Solution
The design incorporates a piston and crankshaft with an eccentric crank pin and counter weights, along with a cylinder bore that has specific cutouts allowing the counter weights and links to pass through, reducing the overall engine height while maintaining structural integrity.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Length of stationary object
If counter weights are disposed on the outer side of the cylinder bore to reduce engine height, then the engine height is reduced, but the bending force acting on the crankshaft increases at high engine speeds
Solution Approach 1:
The invention changes the spatial arrangement by allowing counterweights to extend axially beyond the cylinder bore boundary through cutouts in the cylinder liner. This dimensional repositioning enables the counterweights to be located in a region that does not interfere with piston movement while maintaining their weight-balancing function, thereby reducing engine height without increasing crankshaft bending forces
Solution Approach 2:
The cylinder liner is segmented by introducing cutouts that create separate zones: one for piston reciprocation and another for counterweight rotation. This segmentation allows the counterweights to occupy space that would otherwise be part of the cylinder bore, enabling compact engine design without compromising structural integrity or increasing bending forces
2Shape
If the distance from connecting rod connection part to counter weight is increased to accommodate counter weights outside cylinder bore, then counter weight placement is achieved, but structural preference deteriorates due to increased bending forces
Solution Approach 1:
The counterweights are repositioned in the axial dimension by extending beyond the cylinder bore through cutouts. This allows the distance from the connecting rod connection part to the counterweight to be optimized for balance without being constrained by the cylinder bore boundary, achieving proper counterweight placement while maintaining structural integrity
Solution Approach 2:
The cutouts in the cylinder liner act as intermediaries that mediate between the piston movement space and the counterweight rotation space. This intermediary structure allows both components to coexist in a compact arrangement without interfering with each other, achieving optimal counterweight placement while preserving structural reliability
Data Source
AI summary
An internal combustion engine includes a piston (2) and a crankshaft (33). The crankshaft (33) includes: a journal (33A) as a rotation center; a crank pin (33B) that is located eccentrically with respect to the journal (33A) and rotates integrally with the journal (33A), the crank pin (33b) connecting the piston (2) to the crankshaft (33); and a counter weight (33C) that is located eccentrically with respect to the journal (33A) in a direction opposite to the crank pin (33) and rotates uniformly with the journal (33A). A cutout (11) through which the counter weight (33C) passes is formed in a wall (1) of a cylinder bore that accommodates the piston (2) so as to be free to move reciprocally along the wall (1). As a result, the bottom dead center position of the piston can be lowered, and the overall height of the engine can be decreased.