STEI ITB Welcoming the Era of Electrification with Toyota

Bandung Institute of Technology (ITB) is one of the 3 universities that Toyota has partnered with to develop and welcome the electrification era, one of its efforts is in the development of converting Calya into an electric car.

Agus Purwadi, who is a representative of STEI ITB, at the Webinar ‘University Research Activities as Part of Efforts to Develop the Electrified Vehicle Population’ held by Toyota Motor Manufacturing Indonesia (TMMIN), in its presentation conveyed “Converting from a conventional car (ICE) to a battery-powered electric vehicle (BEV) isn't easy. We're grateful for the opportunity to learn more here. A lot of preparation went into transforming the Calya into a BEV.“.

He also explained the challenges his colleagues at ITB faced when converting the Calya to electric power. He outlined the obstacles they encountered, the impacts they faced, and the solutions they found.

1. Battery Pack (using Toyota Prius 8.8 KWH) does not provide BMS (battery management system).
   Akibat: Measurement of important parameters (Temperature, voltage, Current) and calculations for Protection (Over Charge/Discharge, balance, cooling system), energy characterization (SoC), lifetime (SoH) cannot be performed. Making battery safety vulnerable.
   Solusi: Desain BMS baru berdasarkan karakteristik Battery (NCA).
2. Fluid circulation for the cooling system (Water), braking system (Vacuum air), AT Transmission system (transmission oil) and A/C compressor (Freon) via a fluid pump that is rotated by the ICE.
   Akibat: The Fluid Pump needs to run while the vehicle is operating, but the new drive (electric motor) is more intended for traction (Traction motor).
   Solusi: Design an electric motor-based pump to circulate fluids (cooling pump, vacuum pump, oil pump, electric A/C compressor) according to the system's functional capacity. This includes the controller (TCU, vacuum control, cooling control).
3. Protocol data for control (flow rate, on/off) of Electric- A/C (Prius) is unknown.
   Akibat: Cannot be operated
   Solusi: Replace with electric A/C with open data protocol.
4. The ECU cannot be programmed to ignore (disable) sensor signals originating from the ICE (pressure, temperature, oxygen level, flow rate) nor can it be programmed to reconfigure the function (process).
   Akibat: It cannot be programmed so it cannot be disabled to ignore (disable) the sensor signals coming from the ICE (pressure, temperature, oxygen level, flow rate).
   Solusi: Mimic or manipulate sensor signals coming from the ICE to the ECU.
5. There is no isolation system at high voltage.
   Akibat: Passengers are at risk of being electrocuted or shocked by electric current.
   Solusi: Desain High Voltage Insulation monitoring
6. The AT Transmission system is only capable of transferring power from a maximum electric motor of 22 kW and experiences slip when the electric motor power is > 22 kW.
   Akibat: Torque is limited when going uphill, which requires large torque, or large acceleration to counteract the slope force so that the vehicle tends to slow down, because the traction power output from the AT transmission is not able to counteract the opposing torque from the vehicle, so the vehicle tends to slow down.
   Solusi: Gear shifting has been remapped, given the different torque/power characteristics of an ICE versus an electric motor. However, it hasn't been successful yet.