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World-first Tiny 5-speed auto transmission for evs

Transmission ‘Should-be-used’ in EV
BYGEN NHC 6AT
NHC 6AT - Advantages
Competitiveness of NHC 6AT
NHC 6AT – Design & Connecting
Product Story
NHC 6AT – Advantages
No Hydraulic & Clutch 6Gears Auto Transmission
Pre-conditions of auto transmission
• There should be no shift interruption for comfortable riding and product durability.
• Fast gear shifting within 0.2 second
• Sophisticated TCU (Transmission Control Unit)
Qualified pre-conditions
Seamless gear shifting without sifting time, TCU completed
‘Zero-Time Gear Shifting’ in Bygen’s transmission overcoming the barrier of 0.2 second of shift time is the hidden technology and
       cannot be duplicated without combined understanding of the design for mechanical hardware technology and software solutions in TCU.
Conventional auto transmission problems solved
Eliminate the cause of battery consumption on transmission: No hydraulics (or alternates) and clutches, which consume over 10% energy
  out of the vehicle energy due to the increasing mass.

Problems of vehicle weight gain and mounting space: Light weight and small dimensions enable it to be mounted without changing EV
  platform. In-wheel type can be mounted on trailing arm, while axle type is done with the differential gear box
innovative shifting mechanism
• Gears are shifted by synchronizers, which are composed with more than two pawls at each speed and located in the main shaft.
  Creatively, it is done while all gears are rotating with the same speed of the main axle, which using cam principles and the inertial power.

Innovative shifting mechanism not using extra outer power for gear shift and maintaining
"Zero Shift Time" and no power
  interruption
Innovative change of EV power control system
Inefficient motor power control system in currently commercialized EVs
    • Unlikely industrial electric motor, current EV motor control system should be accompanied by overheats and high frequency noise
   
Electric energy waste, Fluid cooling system, Complicated control algorithm
High EV manufacturing costs
    • Impossible continuous driving at steep hill over 30% decline, which causes steep efficiency decline at continuous uphill drive

Efficient motor power control system
    • Motor always runs at the rated RPM range
No overheats & high frequency noise
Performances and efficiency improvement
   
Significant EV cost-cut
    • Possible continuous driving at steep hill over 30%, while it does not cause any overheats and high frequency noise at high speed drive
Efficiency Graph of BYGEN’s NHC 6AT
NHC 6AT : Cost-cut factors
▶ NHC 6AT makes smaller motor to provide wider range of rpm and torquewithout using field weakening control.
    • With the same top speed with single speed motor, motor of half output creates twice stronger torque at the first gear.
    • Motor always runs at the rated output range with rated rpm (rated voltage) and rated torque (rated ampere),
       which is the one-third power of max power of single speed motor to use field weakening control.
       Max permitted torque (max permitted ampere) is 1.5 times of the rated torque (output is produced around 1.5 times as        well), which is temporally allowed before overheat.
▶ Six-speed gear shift with squeezed gear-by-gear change ratio enables the motor to run in the rated rpm range with high        efficiency.
▶ Energy consumption is reduced for motor operates from low gear to high gear
Ampere (A) is proportionally
      consumed to load.
▶ Max permitted torque (max permitted ampere) is limited to use in power mode “ON”
It is seldom used.
    • It is programmed to be “OFF” after it passes for about 5 minutes, or heat is elevated to overheat point.
    • As shown in above graph, efficiency drastically drops after passing over rated output with overheat, which results
      destruction of motor and controller
Fluid cooling system indispensable
※ Extreme overheat at max output causes controller and motor too severe damage. Motor should run within 10 to 20
      seconds at max output.