The E-Bike Assistance Ratio Test Machine is specifically designed to evaluate the relationship between rider input power and motor assistance power in electric bicycles. The system accurately measures crank power, motor power, total vehicle power, assistance ratio, torque, speed, and rear-wheel driving force, providing manufacturers, testing laboratories, certification bodies, and R&D teams with reliable data for product development and regulatory compliance.
The machine is particularly suitable for EN 15194 pedelec testing, where assistance ratio verification plays a critical role in determining whether an electric bicycle complies with legal power-assist requirements.
Using a servo-driven crank system and a servo-controlled rear-wheel loading system, the test bench simulates real riding conditions at different speeds and resistance levels while automatically generating test reports and performance curves.
Applicable Standards
EN 15194 – Electrically Power Assisted Cycles (EPAC)
ISO 4210 – Cycles Safety Requirements
DIN Standards
BS Standards
CPSC Requirements
Custom laboratory and OEM internal testing specifications
Key Testing Functions & Testing Logic
1. Assistance Ratio Testing
Testing Logic:
The rider's pedaling input is simulated through the crank drive system while a controlled resistance load is applied to the rear wheel. The system simultaneously measures:
The software calculates:
Crank Power
P1=0.105×N×TP1 = 0.105 \times N \times TP1=0.105×N×T
Vehicle Output Power
P2′=0.278×V×FP2' = 0.278 \times V \times FP2′=0.278×V×F
Corrected Total Power
P2=P2′+PclP2 = P2' + PclP2=P2′+Pcl
Assistance Ratio
α=P2−P1P1\alpha = \frac{P2-P1}{P1}α=P1P2−P1
This allows engineers to determine exactly how much motor assistance is being delivered relative to rider input.
2. Pedal Power Measurement
Measures the mechanical power generated through the crank system under different simulated riding conditions.
Purpose:
Verify rider input contribution
Evaluate drivetrain efficiency
Compare assistance performance across drive modes
3. Motor Power Measurement
Calculates the power supplied by the electric drive system independently from rider input.
Purpose:
Validate motor performance
Analyze controller tuning
Optimize energy efficiency
4. Simulated Climbing Resistance Test
A servo motor applies programmable rear-wheel resistance to simulate various gradients.
Purpose:
Tests assistance ratio at different vehicle speeds.
Purpose:
Determine assist cut-off characteristics
Verify legal speed assistance limits
Optimize riding experience
Main Features
High-Speed Servo Rear-Wheel Loading
The rear wheel is loaded using a servo-controlled resistance system that provides:
Fast response
Precise load control
Stable repeatability
Servo-Driven Crank System
The crank is driven by a servo motor with programmable speed profiles.
Benefits include:
Automated Data Acquisition
Real-time monitoring of:
Crank speed
Crank torque
Vehicle speed
Rear-wheel driving force
Crank power
Total power
Assistance ratio
Automatic Report Generation
Export test data in:
with performance curves and compliance reports.
Technical Specifications
Item | Specification |
Test Function | Assistance Ratio Testing |
Crank Drive | Servo Motor |
Rear Wheel Loading | Servo Motor Dynamic Resistance |
Measured Parameters | Speed, Torque, Force, Power, Assistance Ratio |
Test Speed Range | Programmable |
Data Output | Real-Time Curves & Reports |
Power Supply | 380V |
Installed Power | 13 kW |
Test Bench Size | 3580 × 2370 × 1940 mm |
Control Cabinet Size | 1750 × 1030 × 1420 mm |
FAQ
Q1: What is the purpose of an E-bike assistance ratio test?
The test verifies how much motor assistance is provided relative to rider pedaling input. This is a key requirement for EN 15194 compliance and helps manufacturers ensure their e-bikes meet regulatory and performance targets.
Q2: Why measure both crank power and total power?
Assistance ratio is calculated from the difference between rider-generated power and total vehicle output power. Measuring both values allows engineers to quantify the actual contribution of the motor and evaluate system efficiency.
Q3: Can the machine simulate hill climbing conditions?
Yes. The servo-controlled rear-wheel loading system applies programmable resistance, simulating different road gradients and climbing conditions without requiring outdoor testing.
Q4: How does the machine calculate motor assistance?
The system first calculates crank power from pedal torque and cadence, then calculates total vehicle power from speed and driving force. The difference between the two represents motor contribution, which is used to calculate the assistance ratio.
Q5: Who typically uses this equipment?
Typical users include:
E-bike manufacturers
Motor suppliers
Battery manufacturers
Independent testing laboratories
Certification organizations
University research centers
Product development teams
