Plug-In Hybrid (PHV)
This is a variation on the standard hybrid, with an enlarged battery that you can charge at night. This lets you drive using the battery alone – but when the battery is drained, a gas engine kicks in, giving you unlimited range. I have tested two cars that feature this technology: the Chevrolet Volt and the Toyota Prius PHV. Both are excellent, but each is optimized for a different mission. The Volt has an extremely large battery, and will go up to 80 km before the gas engine kicks in. The Prius PHV will only go about 25 km on battery alone. Both cars achieved spectacular mileage. (The calculations get complicated, but I did better than 100 mpg in both after gas and electricity used were factored in.)
Of the two, I considered the Prius the better engineering compromise – the 25-km battery range let me run urban errands for weeks on end without using any gas and, when I went beyond battery range, the PHV was almost as efficient as a regular Prius, with highway mileage in the 4.5 litres/100 km range. The Volt was spectacularly efficient while running on its battery, but not once the gas engine kicked in – the massive battery needed for that long electric range turns into dead weight once it’s depleted. For all-round performance, the Toyota PHV was the winner, but the Volt is not a bad choice. The downsides of the PHV include high initial cost and reduced luggage space thanks to those big batteries. I would recommend a plug-in hybrid to anyone who lives in an urban environment.
I am a fan of diesel engines – I like their low, rumbling sound, their Clydesdale-like torque and their longevity. Then there’s the built-in efficiency – a litre of diesel fuel contains more energy than a litre of gasoline, and a diesel burns its fuel more efficiently than a gas engine thanks to its higher compression ratio and combustion temperatures.
I achieved more than 50 mpg in the VW Golf TDI – this is a car beloved by hyper-miling fuel economy buffs, and I soon understood their passion. Thanks to its small size and aerodynamics, the Golf is a relatively efficient car with any engine, but the diesel put it over the top. The BMW X5 diesel SUV also demonstrated the fuel-efficiency of this powerplant choice – on a trip to the deep south, my wife and I did more than 27 mpg (10.4 litres/100 km). That may not sound particularly impressive until you consider that this is a large vehicle, and that our load included a 400-pound garage compressor. The diesel isn’t the absolute efficiency champion, but it’s up there. Should you buy a diesel vehicle? Yes – at least if you can. (In the North American market, the choice of diesel vehicles is limited.) Other caveats include higher initial cost and fuel availability issues – diesel fuel can be harder to find than gasoline. (Note that many GPS systems will find diesel stations for you.)
Gasoline Internal Combustion (IC)
Although it’s the least efficient of the five powertrain options, the four-stroke, gas-powered engine is is still the optimum choice for many drivers. Although it lacks the technical chic of the hybrid or the electric, the IC gas engine gets the job done: driving carefully, I have routinely hit more than 50 mpg (5.6 litres/100 km) in gasoline-powered cars like the Toyota Yaris and Honda Fit, and have done better than 60 mph (4.7 litres/100 km). (As always, efficiency depends on more than just the power plant – aerodynamics, weight and driving style will determine how far a given engine will carry you on a litre of fuel.) The gasoline engine still has some major attractions, including low cost and fuel availability (you can buy gasoline anywhere).
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