Inline Four Yoke Assembly to Eliminate Secondary Imbalance
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Solution Overview
Problem
Conventional inline four cylinder engines suffer from secondary imbalance due to pistons moving in pairs, causing severe loads on the crankshaft and bearings, which limits engine displacement and leads to premature failures.
Innovation Solution
The design incorporates unopposed cylinder units with yoke assemblies where the piston connecting rod assembly reciprocates exclusively along the bore axis, eliminating secondary forces by having a connecting rod bearing housing that reciprocates within a transverse slot, interfacing with a crankshaft journal, and using slide bearings to prevent lateral movement.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If conventional connecting rod design is used where the lower end reciprocates circularly with the crankshaft, then the engine can operate, but secondary imbalance forces are generated causing severe loads on crankshaft and bearings
Solution Approach 1:
The patent extracts the circular reciprocating motion from the connecting rod assembly and transfers it to a dedicated connecting rod bearing housing that slides in a transverse slot. The connecting rod itself is constrained to move only vertically along the bore axis, separating the vertical piston motion from the circular crankshaft motion and eliminating the secondary imbalance forces generated by the conventional connecting rod design
Solution Approach 2:
The connecting rod bearing housing acts as an intermediary component between the vertically moving connecting rod and the circularly moving crankshaft journal. It converts the vertical linear motion into circular motion through sliding in the transverse slot, while the slide bearings constrain the connecting rod to vertical motion only, thus mediating the motion transfer without generating secondary forces
2Device complexity
If pistons are arranged in pairs moving together in an inline four cylinder engine, then the engine structure is compact, but secondary imbalance is created causing vibration at high rpm
Solution Approach 1:
The patent extracts the circular motion component from the connecting rod assembly and places it in the connecting rod bearing housing that slides in the transverse slot. This separation allows the connecting rod to move purely vertically, eliminating the secondary imbalance forces that arise from paired piston motion in conventional inline four cylinder engines
3Ease of operation
If connecting rods are allowed to swing laterally, then the mechanism can accommodate crankshaft rotation, but rotational vibration on the X axis is amplified
Solution Approach 1:
The patent applies different motion constraints to different parts of the system: the connecting rod is constrained to vertical motion only (local constraint at the connecting rod), while the connecting rod bearing housing is allowed to slide in the transverse slot to accommodate the circular motion of the crankshaft journal (local freedom at the bearing housing). This localized differentiation eliminates lateral swinging and reduces rotational vibration
Solution Approach 2:
The connecting rod bearing housing serves as an intermediary that absorbs the lateral motion requirements through sliding in the transverse slot, while the slide bearings prevent lateral movement of the connecting rod itself. This intermediary structure resolves the conflict between needing flexibility for crankshaft rotation and preventing lateral swinging that causes vibration
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
This configuration eliminates secondary imbalance, allowing for greater engine displacement and reducing the risk of crankshaft and bearing failures, enabling higher revving capabilities without the limitations of conventional inline four cylinder engines.
Implementation Method 1
a connecting rod bearing housing that is mounted in the transverse slot and that is configured to reciprocate within the transverse slot, and which is further configured to house a connecting rod bearing to interface with a connecting rod journal of a crankshaft
Implementation Method 2
using slide bearings to prevent lateral movement
Data Source
AI summary
An internal combustion engine includes one or more unopposed cylinder units where each cylinder unit drives the crankshaft via a yoke assembly rather than a conventional connecting rod. The yoke assembly is formed by a connecting rod assembly that can have an upper portion having a connecting member connected to the piston, and a lower portion. The connecting rod assembly moves exclusively along the bore axis of the cylinder, with no side to side motion. The connecting rod assembly also defines a transverse slot in the yoke portion in which a connecting rod bearing housing reciprocates with motion of a connecting rod journal on the crankshaft within the transverse slot. Since the motion of the connecting rod is linear, and the connecting rod bearing housing moves circularly, there are no secondary forces resulting in an inline engine using the unopposed cylinder unit configuration.