Unbalanced Accessory for Crankshaft Deflection Reduction
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Solution Overview
Problem
Existing engine balancing methods, such as harmonic balancers, fail to effectively reduce crankshaft deflection and vibration at the output, leading to significant vibration transfer to the drivetrain and load, and adding weight and size to the engine, while manual balancing methods do not account for the harmonics of the entire rotating assembly.
Innovation Solution
An unbalanced crankshaft mounted accessory is configured to externally balance the rotating assembly by determining a specific counterbalance weight and angle based on crankshaft deflection measurements across various speeds, allowing for mass production without individual adjustments, and is affixed to the crankshaft at the output to reduce deflection and vibration.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Object-affected harmful factors
If a harmonic balancer is added to reduce crankshaft vibrations, then crankshaft vibrations at the front are reduced, but the engine weight increases and the crankshaft deflection at the output remains significant
Solution Approach 1:
The patent applies counterbalancing weights attached to the crankshaft at specific locations and angles to create counteracting forces that balance the rotating assembly. This external counterbalancing method reduces vibrations without requiring a large harmonic balancer, thereby minimizing weight addition while effectively reducing both front and output crankshaft vibrations
Solution Approach 2:
The patent moves the balancing approach from a single-dimension harmonic balancer at the front to a multi-dimensional solution with counterweights positioned at various locations and angles around the crankshaft. This spatial distribution of counterweights allows more effective vibration cancellation across different planes and reduces the need for excessive counterbalancing mass
2Object-affected harmful factors
If a harmonic balancer is added to reduce crankshaft vibrations, then front crankshaft deflection is reduced, but the crankshaft deflection at the output remains significant causing vibration transfer to the drivetrain
Solution Approach 1:
Counterweights are strategically positioned on the crankshaft to directly address deflection and vibration at the output end. By placing counterbalancing masses at specific radial distances and angular positions, the system creates opposing forces that cancel out the harmful vibrations and deflections at the crankshaft output, preventing their transmission to the drivetrain
Solution Approach 2:
The patent applies different counterbalancing strategies to different locations on the crankshaft. Rather than using a uniform approach, counterweights are positioned at specific locations (front, rear, and intermediate positions) with specific weights and angles tailored to address the local vibration and deflection characteristics at each region, optimizing the overall balancing effect
3Strength
If manual balancing is performed by spinning the crankshaft at fixed speed, then crankshaft bending is reduced, but the harmonics of the entire rotating assembly are not accounted for
Solution Approach 1:
The patent transitions from static fixed-speed balancing to dynamic multi-speed vibration analysis. By measuring and analyzing vibrations at multiple operating speeds, the system captures the dynamic behavior and harmonic characteristics of the complete rotating assembly under various operating conditions, enabling counterweight optimization across the entire speed range rather than at a single fixed speed
Solution Approach 2:
The counterbalancing system is designed to address multiple functions simultaneously: it reduces crankshaft bending, cancels primary and secondary harmonics, and minimizes vibrations across the entire operating range. The counterweights serve multiple balancing purposes for different components (crankshaft, pistons, connecting rods) and different vibration frequencies, providing a universal solution for the entire rotating assembly
4Strength
If the rear of the crankshaft is left unbalanced to avoid extending effective crankshaft length, then driveline strength is maintained, but significant vibration is transferred to the load
Solution Approach 1:
Counterweights are positioned on the crankshaft, including at the rear section, to directly counterbalance the rotating assembly and eliminate vibrations at the output. This allows the rear of the crankshaft to be properly balanced without extending the effective crankshaft length or compromising driveline strength, while effectively preventing vibration transfer to the load
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 solution significantly reduces engine vibration and crankshaft deflection by approximately 50%, improves fuel economy, and enhances power transmission by minimizing vibration and noise transfer to the drivetrain and frame, even in engines with manually balanced rotating assemblies.
Implementation Method 1
The accessory is unbalanced at an angle and weight configured to reduce deflection of the crankshaft at the output of the crankshaft
Data Source
AI summary
An unbalanced crankshaft mounted accessory is configured to externally balance the rotating assembly of a particular engine model. In one embodiment, the unbalanced crankshaft mounted accessory is attached to the crankshaft at the output of the crankshaft (i.e., the connection to a load driven by the engine). The accessory is unbalanced at an angle and weight configured to reduce deflection of the crankshaft at the output of the crankshaft (when the unbalanced crankshaft mounted accessory is attached). The weight and angle are determined by measuring crankshaft deflection at various speeds (rpm) throughout the recommended operating range of the engine. The angle and deflection distance are then averaged and multiplied against a rotating mass of the engine and a constant to determine an angle and weight for the unbalanced crankshaft mounted accessory.