Automobile electronics, Electronics, Mechanics, New technology, Power electronics, Temperature, Thermodynamics

Operation of hybrid vehicle

Was published a post about the comparison between electric and combustion engine vehicles. Why not combine the advantages of both and create the hybrid vehicle? It is this post’s subject.

Click in the button below to read the comparison post.

Electric x CombustionClick here

Motor and engine

The hybrid vehicle has a electric motor and an internal combustion engine. Electric motor is used when the internal combustion isn’t efficient: in start and low speed. Because combustion engine has a weak torque in low speed. The graphics show torque and power in function of speed in RPM of combustion engine and electric respectively.

In higher speeds, the electric motor and combustion engine move hybrid vehicle. In braking, electric motor acts like a generator and battery is recharged by regenerative braking. In electric vehicles part 2, I explained the regenerative braking operation, click here to see.

Some hybrid cars have a generator connected to combustion engine to recharge the battery.

Power split device

This component is very important to hybrid vehicles, it is a planetary gear set which links two motor and the engine. The central gear in green is linked to generator, the planet gears in blue are connected to combustion engine and the ring gear is linked to electric motor.

Types of hybrid vehicles

Actually exist three types of hybrid vehicles.

  • Parallel hybrids: The transmission in wheels is connected to both engine and motor. However, the main source of power is the internal combustion engine. This hybrid vehicle can not operate in electric mode. This type can have a battery with lower capacity and is more efficient in high speed.

  • Series hybrid: Combustion engine serves to move a generator which supplies electric motor and batteries. Only the electric motor is connected to transmission which moves the vehicle. It is more efficient in low speed and situations where the car stops and starts with frequency.

This is the architecture of parallel and series type.

  • Combined hybrid: Use the advantages of both types, is the majority of hybrid cars in market. Can operate in electric or combustion mode.

Some combined hybrid vehicles are plug-in, the batteries can be recharged in a recharging station like an electric car.


Although are more efficient, comfortable and sustainable for emitting less gases, than combustion vehicles. Have disadvantages like:

  • Too high price, due to complexity in architecture and construction;
  • High maintenance cost;
  • Bigger weight of batteries and smaller tank fuel;
  • Limitation of batteries;
  • In case of accidents, passengers can be exposed to high voltage wires.

Hybrid vehicle of Itaipu Binacional

Itaipu Binacional and partner companies built the world`s first hybrid bus moved by ethanol, the OEHE.

This bus transported 11 heads of state in 40th Summit of Presidents of Mercosur and Associated States in 2010. Each company built a part of bus.

  • The 3 axis chassi with pneumatic suspension was built by Tutto;
  • The 3 doors bodywork was made by Mascarello;
  • Mitsubishi provided a V6 flex combustion engine;
  • The brushless synchronous generator was built by WEG;
  • Sodium Chloride batteries were provided by Zebra;
  • The inverter with encoder was built by WEG;
  • The electric motor is asynchronous and three-phase, also came from WEG;
  • Air conditioning system was made by Euroar;
  • WEG also built an auxiliar inverter system.


About Pedro Ney Stroski

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