A hybrid system combines different power sources to maximize each one's strengths, while compensating for the others' shortcomings. A gasoline-electric hybrid system, for example, combines an internal combustion engine's high-speed power with the clean efficiency and low-speed torque of an electric motor that never needs to be plugged in.
There are several ways in which electric motors and a gas/petrol engine can be combined.
Toyota perfected the series/parallel or "full" hybrid to deliver the energy-saving benefit of a series hybrid together with the acceleration benefit of a parallel hybrid. Two key technologies — the power split device and sophisticated energy management — make this possible. They constantly optimize the flows of mechanical power and electric power for safe and comfortable vehicle operation at the highest possible efficiency.
Learn more about the various hybrid systems in the Technology File
Toyota's unique hybrid system combines an electric motor and a gasoline engine in the most efficient manner. It saves fuel and reduces emissions while giving ample power.
Taking advantage of the electric motors' low-speed torque at start-off
When the car starts off, Toyota's hybrid vehicles use only the electric motors, powered by the battery, while the gas/petrol engine remains shut off. A gas/petrol engine cannot produce high torque in the low rpm range, whereas electric motors can - delivering a very responsive and smooth start.
Energy-efficient motor-driven running
A gas/petrol engine is not energy efficient in running a car in the low-speed range. On the other hand, electric motors are energy efficient in running a car in the low-speed range.
Therefore, Toyota's hybrid vehicles use the electric energy stored in its battery to run the car on the electric motors in low-speed range.
*If the battery charge level is low, the gas/petrol engine is used to turn the generator to supply power to the electric motors.
Energy-efficient driving, using the gas/petrol engine as the main power source
Toyota's hybrid vehicles use the gas/petrol engine in the speed range in which it operates with good energy efficiency.
The power produced by the gas/petrol engine is used to drive the wheels directly, and depending on the driving conditions, part of the power is distributed to the generator. Power produced by the generator is used to feed the electric motors, to supplement the gas/petrol engine.
By making use of the engine/motor dual powertrain, the energy produced by the gas/petrol engine is transferred to the road surface with minimal loss.
*If the battery charge level is low, the power output from the gas/petrol engine is increased to increase the amount of electricity generated to recharge the battery.
Recharging the battery with surplus energy
Since Toyota's hybrid vehicles operate the gas/petrol engine in its high efficiency range, the gas/petrol engine may produce more power than is necessary to drive the car. In this case, the surplus power is converted to electric energy by the generator to be stored in the battery.
Dual power for acceleration one class higher
When strong acceleration is called for (e.g, for climbing a steep slope or overtaking) the power from the battery is supplied to the electric motors to supplement driving power. By combining the power from the gas/petrol engine and the electric motors, Toyota's hybrid vehicles deliver power comparable to cars having one class larger engine displacement of one class higher.
Storing regenerated energy under deceleration in the battery
Under braking or when the accelerator is lifted, Toyota's hybrid vehicles use the kinetic energy of the car to let the wheels turn the electric motors, which function as regenerators. Energy that is normally lost as friction heat under deceleration is converted into electrical energy, which is recovered in the battery to be reused later.
Shutting down entire powertrain when the car is at rest
The gas/petrol engine, the electric motors and the generator are automatically shut down when the car comes to rest. No energy is wasted by idling.
*If the battery charge level is low, the gas/petrol engine is kept running to recharge it. In some cases, the gas/petrol engine may be turned on in conjunction with the air-conditioner switch operation.
Learn more about the technologies behind Toyota's Hybrid Vehicle in the Technology File