World-first Compact 7 gears auto transmission for evs
Items | Single Speed EV (AS-IS) |
NH7AT EV (TO-BE) |
Remarks |
---|---|---|---|
Efficiency (km/kWh) | - | Increase by 50% | 1/3 battery capacity (60kWh40kWh) |
Driving System | Vehicle speed totally depends on motor speed. | Multi gears control torque and rpm while electric motor runs within rated range. | |
Cooling System | Fluid cooling system indispensable | No cooling system | No over-temperature due to motor operating within rated range. |
Motor | IPMSM | IPMSM | IPMSM and BLDC Motor are almost same. |
Control System | Expensive inverter to use field weakening control | PCU(Powertrain Control Unit)
MCU(Motor Control Unit) + TCU(Transmission Control Unit) |
Size of price of PCU decrease by 50%. |
Transmission | 1st gear reduction by reducer | Weight is less than 20kg including reducer and shock absorber. | Total size of motor and transmission is smaller than conventional motor including reducer. |
Durability | Little possibility to early repair parts due to no load on shifting and maintaining gears. | see ‘NH7AT Shifting Mechanism' | |
Vehicle weight | Smaller battery, No cooling system. | Realization of lightweight | |
Torque-RPM | Narrow torque-rpm combination | Wider range of torque-rpm range | 4 times stronger output torque than single speed motor |
Powertrain Costs (controller + motor + Transmission) |
Expensive inverter and motor | Total cost including transmission is lower than single speed EV. | • PCU costs 1/3 lower than inverter. • No cooling system (motor and inverter) |
Total cost | • Expensive battery cost • Cooling system cost • High frequency noise blocking cost • Expensive powertrain |
• Reducing (1/3) battery cost • No cooling system(motor & controller) • No high frequency noise • Reducing (1/2) controller cost |
Prominent cost-down for EV |