GrinB’s 6th EV (4) Reducer

A reducer reduces certain amount of RPM(Revolutions Per Minute) to create the desired torque.

In the previous post, I explained that the engine is replaced by the motor in EVs. Likewise, complicated transmissions such as DCTs are replaced into reducers(which is also a type of transmission) in EVs.​

Then, what is a transmission?

The function of transmissions is similar to reducers, but the main difference is that transmissions can adjust RPM up and down. Adjusting engine’s RPM determines the torque which leads to modifying the speed. On the other hand, reducers only lower the RPM because, EVs’ RPM is overwhelmingly larger than internal combustion cars. By lowering RPM, the torque increases which leads to acceleration. To be more detailed, stepping on the accelerating pedal would alter the voltage and frequency through the inverter which lowers RPM. This is convenient because, it removes the burdensome process of gearshifting and creates smooth acceleration.​

The advantages of replacing tranmissions with reducers are the following:

i) Decrease of gears creates smooth and rapid response.

ii) Lower probability of crashing.

iii) No need to exchange transmission oil.​

How are reducers progressing?

Hyundai independently developed an all-in-one EV driving system which contains reducer, motor and inverter.

In the past, the inverter was mostly placed in the engine room which makes the electricity-supplying cable inevitably long. And it also needs a case and chiller which will also occupy space and weight. But this all-in-one EV driving system is small and cheap which is very appealing to the market.

Source: Hyundai