There is no need for compromise, not with innovation leading the way. Thanks to Toyota’s next generation power train, Hybrid Synergy Drive. This all-new Prius has all the power of a conventional car but fewer of its draw backs. As TMC President Fujio Cho stated at the New York Auto Show new Prius unveiling in April 2003, It does everything on earth better and is far better for our earth.
Simply put, it’s not just a green car; it’s a great car. It offers solution, not merely upgrades. In 1997, Toyota Motor Corporation (TMC) took a big step towards the car of the future with the introduction of the world’s first mass-produced hybrid vehicle. Gasoline – electric hybrid technology is not a transitionary stage; it is one of the solutions to the problems facing the environment. By combining gasoline engine and electronic motor technology, hybrids can be driven all over the world with substantially less impact on the environment.
Hybrid Synergy Drive has power and fuel efficiency; the battery does not need to be plugged in; there is no added maintenance; and Toyota will soon offer hybrid alternatives throughout its lineup. More compact and modular than the Toyota Hybrid System (Which powered the first generation Prius) this drive train can be tailored to the needs of many different platforms from Sedans SUV’s and trucks.
What is Hybrid
A hybrid system combines different power sources to maximize each one’s strengths, while compensating for each other’s shortcomings. A gasoline-electric hybrid system, for example, combines an internal combustion engine’s highspeed power with the clean efficiency and low-speed torque of an electric motor that never needs to be plugged in.
It is really feasible to produce a car that offers advanced performance features while also preserving the environment.
Ordinary powertrains waste energy at stoplights, during braking, and all other times the engine is not running at optimum speed under ideal load conditions. By reducing energy wastage and applying energy more efficiently, a hybrid system can simultaneously double fuel economy, slash emissions and deliver “fun to drive” performance.
- High Expansion Ratio Atkinson Cycle Gasoline Engine
The engine operates at optimum speed for high efficiency. This 1.5-liter engine also extracts more energy from gasoline combustion by using the high xpansionratio Atkinson Cycle.
To charge the battery and supply power to the highoutput motor, the generator is rotated at up to 10,000 rpm (vs. 6,500rpm in Toyota’s previous hybrid system). This improves acceleration at low and medium speed.
The sealed nickel-metal hydride (Ni-MH) battery is more compact and has higher power density than Toyota’s previous battery. It is charged by the engine via the generator at cruising speed, and by the motor during regenerative braking.
- Power Split Device
This splits power from the engine into two routes: mechanical and electrical. Its planetary gear can transfer power between engine, motor, generator, and wheels in almost any combination. Also called “hybrid transaxle.”
This permanent-magnet electric motor features neodymium magnets in an optimum V shape, to produce 50kW high output and high torque at 500V, a 1.5 times improvement over Toyota’s previous hybrid system.
- Regenerative Braking
Instead of wasting energy as heat, this system uses the motor as a generator to convert braking energy into electricity. It is particularly effective in stopand-go city driving.
- Power Control Unit (Inverter)
This contains an inverter that converts DC from the battery into AC for driving the motor. Its high-voltage power circuit raises the power supply to 500V, up from 274V in Toyota’s previous hybrid system.
How Hybrid Works
Only the electric motor is used for start-up and low to mid-range speeds.
When cruising, the engine and motor both drive the wheels: engine power is split between the wheels and an electric generator, which in turn drives the motor. Power allocation is controlled to maximize efficiency. As necessary, the generator also recharges the battery from surplus engine power.
- Hard Acceleration
The battery supplies additional energy to boost drive power, while the engine and motor provide smooth acceleration response.
- Deceleration/ Braking
The high-output motor acts as a high-output generator, driven by the car’s wheels. This “regenerative braking system” recovers kinetic energy as electrical energy, which is stored in the high-performance battery.
Goals of Hybrid
In developing Hybrid Synergy Drive, Toyota sought ways to strengthen engine and motor power, raise electric power, and improve energy management for more efficient and effective control of the energy made available. The benefits are world leading environmental performance and more powerful acceleration for a higher “fun to drive” quotient.
- A More Powerful Synergy
In a conventional powertrain, there is a tradeoff between power and efficiency. If you try to raise one, you reduce the other. All things being equal, the larger your engine, the lower your gas mileage. Hybrid Synergy Drive rearranges this relationship. Instead of compromising or sacrificing, it seeks synergies.In the new Prius, Hybrid Synergy Drive achieves a more powerful synergy by boosting the hybrid system’s voltage to a maximum of 500V (up from 274V in the previous Prius). A higher voltage means that electrical power can be supplied to the motor using a smaller current to increase efficiency. Or, if current is kept the same, the higher voltage can be used to raise power.
- More Fun To Drive
In addition to its highvoltage power circuit, Hybrid Synergy Drive also employs a higher-performance battery and a higher-speed motor and generator. Together with enhanced energy management, these enable 1.5 times the motor power of Toyota’s previous hybrid system, while attaining even greater fuel economy.Side benefits include “torque on demand,” an innovation that gives added traction on slick roads by taking advantage of the power split device.For the driver, the combination of greater motor power and engine power, plus greater control in Hybrid Synergy Drive provides a more powerful, smoother and safer driving experience. It’s a solution whose time has come, just in time.