E-bicycle Gear Shift Control System

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Solution Overview

Problem

Existing E-bicycles with integrated electric motors do not optimize motor operation, leading to shortened battery charge life and inefficient gear shifting, particularly for casual riders who may not make optimal gear selections.

Innovation Solution

A control system that optimizes gear shifts based on real-time data from bicycle speed, pedal cadence, motor output, terrain, and rider conditions, using a microprocessor to automatically adjust gear ratios and suggest shifts to the rider, incorporating learning and training modes to tailor shifting protocols to individual preferences.

Engineering Contradictions & Design Principles

VSEngineering Contradiction Analysis

1Measurement precision

If an electronic gear shifting device is used, then gear shift precision and speed are improved, but device complexity increases

Engineering Contradiction:
Improvegear shift precisionVSAvoidshifting mechanism complexity
Core Design Contradiction:
Measurement precisionVSDevice complexity

Solution Approach 1:

The patent combines the electronic gear shifting device with the electric motor control system into a single integrated controller. The motor controller receives gear shift commands from the electronic shifter and coordinates motor torque delivery with gear changes, merging two separate control functions into one unified system that reduces overall complexity while maintaining precision.

Inventive Principle:
Principle #5Merging (Combining)

Solution Approach 2:

The motor controller is designed to perform multiple functions: it controls motor torque, manages battery power delivery, and processes gear shift commands from the electronic shifter. This multi-functional approach eliminates the need for separate control circuits for each function, reducing device complexity while maintaining precise gear shifting capability.

Inventive Principle:
Principle #6Universality (Multi-functionality)

2Productivity

If manual gear shifting is used, then device complexity is reduced, but riding efficiency deteriorates for casual riders

Engineering Contradiction:
Improveriding efficiencyVSAvoidgear shifting ease
Core Design Contradiction:
ProductivityVSEase of operation

Solution Approach 1:

The system incorporates sensors that automatically detect riding conditions such as pedal cadence, motor load, and battery state, and the controller automatically determines optimal gear shifts without rider input. This self-service capability allows casual riders to achieve optimal riding efficiency without needing to understand or manually adjust gear selections.

Inventive Principle:
Principle #25Self-service

Solution Approach 2:

The system continuously monitors riding parameters through sensors and uses this feedback to automatically adjust gear selections. The controller receives real-time data on pedal cadence, motor torque, and battery state, processes this information, and automatically commands gear shifts to maintain optimal efficiency, creating a closed-loop control system that adapts to changing riding conditions.

Inventive Principle:
Principle #23Feedback

3Duration of action of moving object

If motor operation is not optimized, then ease of operation is improved, but battery charge life deteriorates

Engineering Contradiction:
Improvebattery charge lifeVSAvoidcontrol system complexity
Core Design Contradiction:
Duration of action of moving objectVSDevice complexity

Solution Approach 1:

The motor controller continuously monitors battery state of charge, motor load, and riding conditions, using this feedback to optimize motor operation in real-time. The controller adjusts motor torque delivery and gear selection to keep the motor operating in efficient ranges, extending battery life while maintaining rider performance expectations.

Inventive Principle:
Principle #23Feedback

Solution Approach 2:

The system dynamically adjusts motor control parameters based on real-time conditions rather than using fixed control strategies. The controller modifies torque curves, gear shift timing, and power delivery characteristics dynamically to optimize battery efficiency across varying riding conditions, load levels, and battery states.

Inventive Principle:
Principle #15Dynamics

Data Source

PatentEP3068683B1Automatic gear shift system for an e-bicycle
Publication Date: 2020.02.26 ROBERT BOSCH GMBH
  • EP3068683B1 patent drawingFigure 1
  • EP3068683B1 patent drawingFigure 2~3
  • EP3068683B1 patent drawingFigure 4

AI summary

An automatic gear shift system is provided for an E-bicycle that maximizes the contribution of the electric motor assist of the bicycle while minimizing the instances in which the electric motor assist is invoked. A control system monitors several sensors and particularly the change in sensor data at discrete intervals. If the change in certain sensor data exceeds predetermined thresholds the control system directs an electronic shifting device to execute an upshift or downshift of the bicycle's gearing, as appropriate for the conditions. The control system also determines whether additional thresholds are exceeded, in which case the control system activated the electric motor to assist the rider.