Lexus GS450h; photo by Laurance Yap. Click image to enlarge
By Jim Kerr
Green and White do go together. Think of Christmas trees and snow or striped peppermint candies – but do “green” hybrid cars go with a white Canadian winter? How do the batteries work when the temperatures dip far below freezing? That insight had eluded me until a couple weeks ago, when I finally had the opportunity to test a hybrid car during a Canadian cold snap. What I discovered may help you make the decision about parking a hybrid vehicle in your driveway.
Hybrids come in various types. Any combination of power sources or powertrains could be a hybrid, but the current generation of hybrids consist of gasoline engines combined with electric motors. While hybrid city buses have been on the road for several years, Toyota, Lexus, Honda, Saturn, Ford and Chevrolet hybrid passenger vehicles are on the market right now and we can expect to see many others in the near future. Even Ferrari presented a hybrid car concept at the North American International Auto Show this year.
Hybrids can be classed as Series, Parallel or combined Series/Parallel types. Diesel locomotives are typical of a series system. The diesel motor turns a generator, which produces power for the electric motors. Batteries are not used, but could be to average out the supply and demand for electricity.
A Parallel hybrid system moves the vehicle with both propulsion systems, where the two propulsion systems complement each other. Electric motors produce their maximum torque at low rpm. Gasoline engines produce power and torque at higher rpm. By combining them, the vehicle is powerful through all vehicle speeds.
Series/Parallel systems are the design found in current hybrids. These systems can operate on either propulsion system independently, or both together. To complicate matters slightly, GM has a “mild” hybrid. The Saturn Vue, Aura and the Chevrolet Malibu hybrids use low voltage (36-volt) hybrid systems that assist acceleration and recover energy during deceleration, but can only provide minimal propulsion with just electric power. Other vehicles such as the Ford Escape, Honda Civic and Toyota Camry, Prius and Highlander are “full” hybrids, capable of operating on electric power only.
My experience with the Lexus GS450h hybrid sedan was very positive. This car uses the Toyota Hybrid Synergy Drive design. A 3.5-litre V6 gasoline engine is combined with a CVT transmission that contains two motor/generator units. The vehicle can operate up to about 60 km/h on electric propulsion if light throttle is used. Accelerate a little faster and the gasoline engine starts up to provide power too.
Lexus GS 450h; photo by Laurance Yap. Click image to enlarge
I have driven several Toyota and Lexus vehicles in the summer and without the energy display on the dash, you would soon forget it is a hybrid. They drive like any other car, other than when you start it. Press the start button and a “Ready” light on the dash is the only indication that you can drive away. With the thermometer hovering around minus 30, the Lexus GS450h acted the same way – for a few seconds. The “Ready” light would come on and the gasoline engine would remain off. Then the gasoline engine would start up, producing interior heat.
I did find that the high efficiency of the gasoline engine in this hybrid did take longer to warm up the car interior. Fortunately, electric seat heaters took the chill off. Start driving and the interior warmed up much quicker.
In light throttle city driving, I often found the vehicle moving on electric power. The gasoline engine may have been running, but it was charging the high voltage battery pack instead of propelling the vehicle. Accelerate a little faster and both would provide power to the wheels. During deceleration, the electric motors became generators to capture energy normally wasted by braking. Again, the gasoline engine would often be operating, but only to charge the battery. The hybrid battery remained about 80% charged throughout a week of cold weather driving.
With the vehicle at a stop light, the gasoline engine would often turn off until the interior of the vehicle began to cool down. Then it would smoothly and silently start back up again. If this vehicle didn’t have a display that indicated power flow to and from the motors, the battery and to the wheels, it would be difficult to determine exactly what was driving the car. It was smooth and seamless.
Fuel economy wasn’t as good in the winter as it was in the summer. I achieved an average of 13.2 L/100 km in City driving (it is rated at 8.7 L/100 km City), but this included warm ups and a lot of snow and ice. The increase in fuel consumption is comparable to what I would expect from any vehicle. Overall, I found driving a hybrid in a cold Canadian winter was no different than driving any other vehicle. You just get better fuel economy. It’s easy to be Green in the white.