E-Bike Drive Shutdown Timing Based on Pedaling Cadence
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Solution Overview
Problem
Existing e-bikes with electric drives experience undesirable shutdowns and prolonged operation after pedaling cessation, leading to uncomfortable riding experiences and gear change delays, particularly with hub gears, due to fixed time periods for electric drive deactivation.
Innovation Solution
A control unit adjusts the duration for which the electric drive continues to operate based on the rider's pedaling frequency, varying the shutdown time to match the pedaling cadence, using existing rotational speed data or additional sensors to ensure timely shutdown and facilitate immediate gear changes.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Ease of operation
If a constant predetermined period of time is used for electric drive after-running, then the driver has time to complete pedaling cycle, but the electric drive continues running longer than necessary causing uncomfortable riding and preventing gear shifts
Solution Approach 1:
The patent applies dynamics by making the after-running period variable rather than constant. The control unit adjusts the duration of electric drive continuation based on real-time detection of driver torque presence and pedaling cadence. This dynamic adjustment allows the system to provide sufficient time for pedaling cycle completion while minimizing unnecessary after-running that causes discomfort and prevents gear shifts.
Solution Approach 2:
The patent changes the parameter of after-running duration from a fixed constant to a variable value determined by pedaling frequency and torque detection. When cadence is high, the after-running period is shortened; when cadence is low, it is extended. This parameter change resolves the contradiction by adapting the time duration to actual driving conditions.
2Productivity
If the predetermined period of time is reduced to enable faster gear shifting, then gear changes can occur sooner, but the electric drive interrupts support during low cadence pedaling causing rough riding
Solution Approach 1:
The system dynamically adjusts the after-running period based on detected pedaling cadence and torque characteristics. During high-cadence pedaling, the after-running is shortened to enable faster gear shifting. During low-cadence pedaling with pronounced torque variations, the after-running is extended to maintain smooth support. This dynamic behavior resolves the contradiction between shifting speed and riding comfort.
Solution Approach 2:
The control unit continuously monitors driver torque and cadence, using this feedback to adjust the after-running duration. The system detects when the driver is actively pedaling versus when torque has ceased, and adapts the electric drive shutdown timing accordingly. This feedback mechanism ensures gear shifts occur at appropriate moments while maintaining comfort during variable cadence pedaling.
3Measurement precision
If torque-based detection is used to determine driver input, then the system can detect pedaling status, but the sinusoidal torque curve causes periodic shutdown at bottom dead center
Solution Approach 1:
The system dynamically evaluates torque detection over time rather than using static threshold comparisons. By monitoring torque trends and cadence patterns, the control unit distinguishes between normal sinusoidal torque variations during pedaling and actual cessation of driver input. This dynamic evaluation prevents false shutdowns at bottom dead center while maintaining reliable detection of genuine stop conditions.
Solution Approach 2:
The control unit establishes a predetermined period of time after torque falls below threshold before actually shutting off the electric drive. This preliminary waiting period allows the system to confirm whether the torque drop was temporary (normal pedaling variation) or permanent (driver stopping). This preliminary action prevents unreliable shutdowns while maintaining measurement precision for actual stop detection.
4Reliability
If a monitoring device with fixed time counter is used, then the electric drive continues running after driver stops pedaling, but this causes annoying after-running and prevents timely gear changes
Solution Approach 1:
The patent transforms the fixed time counter into a dynamic timing mechanism that adapts to pedaling cadence. The monitoring device uses variable time periods based on detected cadence: shorter periods for high cadence (enabling faster shutdown and gear shifting) and longer periods for low cadence (maintaining smooth operation). This dynamic timing resolves the contradiction between reliable stop detection and minimizing unnecessary after-running.
Solution Approach 2:
The system changes the time parameter from a constant predetermined period to a variable period determined by cadence and torque characteristics. This parameter change allows the monitoring device to accurately detect driver stop intent while minimizing the delay in electric drive shutdown, thereby enabling timely gear changes without sacrificing detection reliability.
Data Source
Figure 1
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AI summary
The present invention relates to a vehicle, in particular an electric bicycle, that can be operated by muscle power and/or motor power, comprising: a crank mechanism (2) via which a rider torque generated by the rider can be applied, an electric drive (3) which can additionally apply a drive torque, and a control unit (10) which is configured to switch off the electric drive (3) when the rider torque is not present, wherein the control unit (10) includes a monitoring device which ensures that, if a predetermined rider torque is not reached, the electric drive (3) continues to operate for a predetermined period of time (t), and wherein the duration of the predetermined period of time (t) is variable depending on the rider's pedaling frequency (f). The invention further relates to a method for operating a vehicle.