Offset In-Line Four Cylinder Engine Balancer Mechanism
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Solution Overview
Problem
Conventional balancer mechanisms struggle to effectively reduce vibration caused by the secondary inertia couple based on lateral pressures from pistons in offset in-line four cylinder engines.
Innovation Solution
An in-line four cylinder engine design incorporating a double-shaft balancer mechanism with a first balancer shaft and a second balancer shaft, where the distance and magnitude of unbalancing portions on each shaft are strategically adjusted to counteract the secondary inertia couple, allowing the balancer shafts to rotate at twice the speed of the crankshaft and orient their unbalancing forces to align with the secondary inertia couple.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Device complexity
If a conventional single-shaft balancer mechanism is used, then the structure is simple, but it cannot effectively reduce vibration caused by the secondary inertia couple based on lateral pressures from pistons
Solution Approach 1:
The balancer mechanism is divided into two separate shafts (first balancer shaft and second balancer shaft) instead of using a single shaft. Each shaft is positioned at different locations and configured to counteract specific components of the secondary inertia couple, enabling effective vibration reduction that cannot be achieved with a single shaft configuration.
2Volume of moving object
If the balancer shafts are positioned at the same location, then the structure is compact, but the unbalancing forces cannot be properly oriented to counteract the secondary inertia couple
Solution Approach 1:
The two balancer shafts are positioned at different axial locations along the crankshaft rather than at the same location. This spatial distribution in the axial dimension allows each shaft to generate unbalancing forces that are properly oriented to counteract the secondary inertia couple components, achieving effective vibration reduction while maintaining a compact overall structure.
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 engine effectively reduces vibration caused by the secondary inertia couple, even when the phase of the secondary inertia couple is displaced, thereby improving engine stability and reducing operational vibrations.
Implementation Method 1
the first balancer shaft includes a first unbalancing portion that generates an inertia force as the first balancer shaft rotates. The second balancer shaft includes a second unbalancing portion that generates an inertia force as the second balancer shaft rotates
Data Source
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AI summary
Vibration generated by a secondary inertia couple based on the lateral pressures from the pistons (32) of an offset in-line four cylinder engine is reduced. A reference line (L1) is established that passes through the shaft center of the crankshaft (30) and is parallel to the cylinder axes of the four cylinders as viewed in the axial direction of the crankshaft. As viewed in the axial direction of the crankshaft, the direction in which the reference line extends is referred to as first direction, and the direction perpendicular to the first direction is referred to as second direction. At least one of the following (1) and (2) applies so as to reduce vibration generated by a secondary component of an inertia couple based on the lateral pressures from the four pistons. (1) the distance between the shaft center (40C) of the first balancer shaft (40) and the reference line as measured in the second direction may be different from the distance between the shaft center of the second balancer shaft (42) and the reference line as measured in the second direction, and (2) the magnitude of the first unbalancing portion (40A) may be different from the magnitude of the second unbalancing portion (42A).