Almost all the automotive manufacturers offer hybrid models in their vehicle lineup, but if you say hybrid to many drivers, they often think of the Toyota Prius first, helped possibly by the distinctive styling (at the time) that distinguished it from the other vehicles on the road. Although the Prius was the first mass produced hybrid, being introduced in Japan in 1997, Honda beat it to the market with the 1999 Insight in North America.
The Prius hit the world market in 2000 and became an industry leader. Since then the Prius nameplate has become almost as well-known as things such as Kleenex Along with the Camry Hybrid and Rav4 Hybrid, Toyota has been the leader in the Canadian hybrid vehicle market, with more than three quarters of all hybrids sold here since 2000 and more than 10 million hybrids sold worldwide.
This spring, the Automobile Journalists of Canada have selected the RAV4 Hybrid as Green Utility Vehicle of the Year and the Prius as their choice for the Canadian Green Car of the Year. The Prius has become a complete car line, with three different Prius models currently available, soon to be joined by the new 2017 Prius Prime plug-in hybrid model this fall.
The 2017 Prius is still distinctive in styling but has a much sportier look to it, which will undoubtedly increase sales, but it is the hybrid technology and the long-term reliability and fuel economy that attracts buyers to the Toyota hybrid models. Toyota refers to their powertrain as the Hybrid Synergy Drive. It is a combination of small gasoline engine and powerful electric motors that work in synergy to optimize fuel economy while providing good performance.
When you start the vehicle with a push of the start button, the dash display lights up and there is a small “ready” light on the display indicating the vehicle is set to go. The gasoline engine usually doesn’t start right away, so it may feel like the vehicle isn’t started, but when the ready light is on, it is all good. The vehicle’s computer looks at many factors, including outside temperatures, passenger compartment temperatures, engine temperature and driver demand. If the passenger compartment is too cold, the gas engine may start so it can provide interior heat. Place the shifter in drive and you are set to go.
In addition to the gasoline engine, there are two motor/generator units built into the transmission. These can be used to help propel the car or recharge the battery during deceleration. Having two motor/generator units allows one to propel the car while the other recharges the battery at the same time, if the battery becomes too low on charge.
During acceleration, both the gasoline and electric motors are used. Electric motors provide strong torque at low rpm and the gasoline engine uses an Atkinson Cycle design that improves engine efficiency but does reduce low rpm torque. A combination of the two power plants provides good torque throughout the complete drive range. At cruise speed, the computer controls both electric and gas engine to maintain the vehicle speed with the most optimized fuel economy. The vehicle can operate on electric power alone at very low speed and during cruise but only for short distances.
During deceleration, the gas engine is turned off and the motor/generator units both generate power back into the battery. Stepping on the brake pedal lightly will allow the best recapture of energy back into the battery. If you step on the brake pedal more, some of the energy is turned into heat by the friction of the brakes, so efficient drivers will only step on the brake pedal lightly unless a sudden stop is necessary.
Part of the Hybrid Synergy Drive design in a continuously variable transmission (CVT). Other CVT’s use a metal belt and variable pitch pulleys to create different gear ratios. The Hybrid Synergy Drive uses planetary gears and the operation of the two motor/generator units to vary the gear ratios. The motor/generator units are connected to the planetary gears so that when one motor is driving, the other motor can change its speed and direction of rotation to change the speed and rotation of parts of the planetary gear set. This allows a continuously variable gear ratio without the addition of steel belts and pulleys.