Compound Connecting Rod Geometry for Longer Piston Dwell
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Solution Overview
Problem
Internal combustion engines suffer from significant energy loss due to inefficiencies in converting fuel energy to mechanical energy, primarily through waste heat, friction, and imbalance forces on connecting rods, which affect fuel economy and environmental impact.
Innovation Solution
A compound connecting rod system with a connecting rod carrier and collapse blockers that pivot around a crank pin, allowing a non-circular path and reducing sidewall friction, thereby increasing piston dwell time and reducing secondary imbalance.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Duration of action of moving object
If a traditional rigid connecting rod is used, then structural strength is maintained, but piston dwell time is limited and sidewall friction increases
Solution Approach 1:
The connecting rod is divided into two separate components: a connecting rod carrier that pivots around the crank pin, and a connecting rod that pivots within the carrier. This segmentation allows each component to perform its specific function independently, enabling the rod to follow a non-circular path that increases piston dwell time while maintaining structural integrity through the collapse blocker mechanism.
Solution Approach 2:
The connecting rod system transitions from a rigid, fixed-geometry structure to a dynamic, multi-pivot system. The connecting rod carrier pivots around the crank pin while the connecting rod itself pivots within the carrier, creating a non-circular path that dynamically adjusts the piston dwell time during the power stroke.
2Ease of manufacture
If the connecting rod pivot point is positioned at the crank pin, then the connection is simple, but sidewall friction increases and secondary imbalance occurs
Solution Approach 1:
The connecting rod carrier is designed with an asymmetric geometry where the pivot point for the connecting rod is offset from the crank pin center. This asymmetric positioning creates a non-circular path that reduces the angle between the piston and connecting rod carrier, thereby reducing sidewall friction and improving power stroke efficiency.
3Stability of the object's composition
If the connecting rod carrier is made rigid, then structural stability is maintained, but collapse around the crank pin cannot be prevented
Solution Approach 1:
The collapse blocker is designed to change its geometric parameters during operation. It features a flat surface that contacts the connecting rod at varying positions as the carrier rotates, allowing it to dynamically adjust and distribute forces upon the carrier to prevent collapse while maintaining structural stability.
Data Source
AI summary
A compound connecting rod for improving the efficiency of an internal combustion engine. The compound connecting rod includes a connecting rod, a connecting rod carrier, and a collapse blocker. During crankshaft rotation, the compound connecting rod undergoes a non-circular path that increases dwell time of a piston, reduces sidewall friction, and reduces secondary imbalance.