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Technology File - Safety Technology

Toyota Hybrid System (THS II)

<Fuel Economy> Global Top Level1

Leveraging the strengths of both engines and motors for overwhelming fuel efficiency and powerful performance.

There are several types of Hybrid Systems. Toyota’s THS II (Toyota Hybrid System II) is a Series/Parallel Hybrid System. This system uses both a motor and an engine to drive the wheels, and can also generate electricity during motor operation. It runs on the motor, which offers excellent low speed torque, or the engine, with its high speed performance, or a combination of the two, depending on driving conditions, for powerful, high efficiency driving at all times. It also reuses the excess energy produced during standard driving and low speed driving in electrical generation, improving fuel efficiency. The entire system used in the new (2015) Prius was designed to offer the ultimate in high efficiency, compact size, light weight, and low loss, achieving one of the world’s highest levels of fuel efficiency1.

  1. As of December 2015. Gasoline-powered passenger vehicles (excluding plug-in hybrid vehicle). According to Toyota Motor Corporation.
Toyota Hybrid System (THS II)

Basic structure

The system is composed of the electric motor, the engine, the battery, the generator, the power split device and the power control unit (inverter/boost converter/DC/DC converter). The power split device transfers part of the power produced by the engine to drive the wheels, and the rest to the generator to either provide electric power for the motors or to recharge the battery.

Basic structure

Other hybrid systems

In the Series Hybrid System, the electric power produced from the engine drive is fed to the electric motor that drives the wheels. The engine is not used for vehicle drive. The basic components of the system are the electric motor, the engine, the battery, the generator, and the inverter. The low output engine is quasi-steadily operated to drive the generator, which is connected in series to the motor, hence the name Series Hybrid System.
In the Parallel Hybrid System, the wheels are driven by both the engine and the electric motor. The basic components of the system are the electric motor, the engine, the battery, the inverter, and the transmission. Battery power is used to drive the motor, which is used as a generator, so, unlike the Toyota THS II, it is not capable of driving with the motor while generating electricity.

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Specifications may differ depending on country, region, or model.