Variable Speed Alternator With Adjustable Pulley Diameter
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Solution Overview
Problem
Conventional alternators with fixed pulleys have a rotational speed proportional to engine speed, leading to inefficient sizing and increased cost due to larger capacity to handle maximum electrical load at idle conditions, resulting in overcapacity and inefficiency at normal operating ranges.
Innovation Solution
A variable speed alternator with an adjustable pulley assembly and control system that varies the pulley diameter based on engine speed and load demand, allowing for adaptive speed adjustment and reduced capacity usage.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If the alternator is sized to handle maximum electrical load at idle conditions, then the alternator can meet peak demand, but the alternator has larger capacity and is more expensive and less efficient at normal operating ranges
Solution Approach 1:
The patent applies dynamics by making the pulley diameter adjustable rather than fixed. The adjustable pulley assembly allows the alternator to dynamically change its speed ratio relative to the engine, enabling it to operate at optimal speeds across different engine conditions. This resolves the contradiction by allowing the alternator to be sized for peak demand while maintaining efficiency during normal operation through dynamic speed adjustment.
2Reliability
If the alternator is sized to handle maximum electrical load at idle conditions, then the alternator can meet peak demand, but the alternator cost increases due to larger capacity
Solution Approach 1:
The dynamic pulley adjustment mechanism allows for a smaller, more cost-effective alternator design. Instead of requiring a large-capacity alternator to handle peak idle loads, the system uses a smaller alternator coupled with an adjustable pulley that increases the speed ratio when needed, thereby reducing the alternator's physical size and manufacturing cost while still meeting peak demand requirements.
3Device complexity
If the alternator uses a fixed pulley, then the structure is simple, but the rotational speed is directly proportional to engine speed and cannot be optimized
Solution Approach 1:
The patent transitions from a static fixed pulley to a dynamic adjustable pulley system. The adjustable pulley assembly includes moveable members that can change the pulley diameter, enabling the alternator speed to be optimized independently of engine speed. This maintains reasonable structural simplicity while dramatically improving adaptability and speed control capability.
4Loss of energy
If the alternator operates at normal operating range speed, then efficiency is optimized, but the current output is insufficient at idle conditions with fixed pulley
Solution Approach 1:
The adjustable pulley system dynamically adjusts the speed transmission ratio based on operating conditions. During idle conditions, the pulley configuration increases the alternator speed relative to engine speed, ensuring sufficient current output. During normal operating ranges, the pulley maintains an optimal speed ratio that maximizes efficiency, thus resolving the contradiction between power output and efficiency across different operating conditions.
Data Source
AI summary
A variable speed alternator can include a shaft and adjustable pulley assembly coupled to the shaft. The adjustable pulley assembly can include a support member fixed to the shaft and an adjustable pulley moveably coupled to the support member. The adjustable pulley can have a plurality of individually moveable members each with an outer surface forming a portion of a belt engaging surface for receiving a flat belt to drive the adjustable pulley. Each moveable member can be selectively linearly moveable in a radial direction to vary an outer diameter of the adjustable pulley between a first position having a first outer diameter and a second position having a second outer diameter to selectively vary a driven speed of the alternator shaft.