Test Data

Seoul National University of Science & Technology (Eco Automotive Technology Institute)

Test Data
RPM vs. Efficiency
Main Drivers for Increase in Efficiency
Single Speed EV Efficiency Analysis
EV Cost Reduction for Auto Makers
Test Data
Test Organization
Seoul National University of Science & Technology (Eco Automotive Technology Institute)
Test Method
PG (Proving Ground) test at KAIPA and road test in Seoul with own-built prototype EV2W
Test Results
Driving with constant speed at PG: efficiency increased by 50 to 100% by each speed.
Urban road driving in Seoul: efficiency increased by 94%.
Prototype EV2W Specifications
4-speed auto transmissions of Bygen are applied to both front wheel and rear wheel.
Items Bygen "G"
Tested Vehicle Electric 2-wheel motorcycle(2WD) Electric 2-wheel motorcycle
Motor Output 1.5kW(750W x 2) 3.8kW
transmission In-Wheel -
Gear Ratio 4-speed Auto Transmission, Gear Ratio 300%
1st Gear 1:1,    2nd Gear 1.4:1,    3rd Gear 2:1,    4th Gear 3:1
Single speed
Battery 2.400kWh(46.8V, 51.3Ah) 2.448kWh(72V, 34Ah)
Size 1,800 / 700 / 950mm 1,750 / 740 / 1,275mm
Weight 80kg 105kg
Max Speed Test
Venue Measurement Bygen "G"
PG Speed at 400m after the starting point with full acceleration 63km/h 62km/h
Grade Performance Test
Bygen "G"
Consistent performance with gradient of 20.9% 1Consistent performance with gradient of 14.1%
Constant Speed Test
Venue Constant Speed Bygen "G" Efficiency Improving Ratio
Remaining Voltage(V) Efficiency
Range Remaining Voltage(V) Efficiency
Total Per Cell Total Per Cell
PG 30km/h 202.1 42.5 3.27 84.2 101 62.5 3.13 41.3 over 103.9%
40km/h 140 42.2 3.25 58.3 84.1 60.5 3.03 34.4 over 69.5%
50km/h 90.6 43.5 3.35 37.7 61.6 60.85 3.04 25.1 over 50.2%
※Why is the efficiency ratio higher at a lower speed than a higher speed at constant velocity? Please refer to details.
Road Test in Urban Area
Test Area Item Bygen "G" Efficiency Improving Ratio(%)
Dong-Il Ro, Nowon-Gu, Seoul
※ Map seen in Appendix 1
Driving Range 102km 53.5km -
Remaining Voltage per Cell 43.85V, 3.373V 62.4V, 3.12V -
Efficiency(km/kWh) 42.5 21.8 over 95%
※Please note that Bygen’s battery was used within normal range whereas the battery of “G” was discharged during the test which indicates that the actual efficiency improvement will be greater.