How fuel efficiency testing works
Every new vehicle sold in Canada comes with an information sticker on its window, and on almost every one, you’ll see the EnerGuide label showing its fuel consumption. But exactly how is that determined?
You might think it’s done by driving the car on a test track, in perfect weather and with a lightweight driver behind the wheel. But it’s actually done on a dynamometer in a laboratory, which ensures consistency. And on top of it, the engineers don’t look at what’s left in the tank. Rather, they measure the amount of carbon in the exhaust to determine how much fuel was used.
And while Natural Resources Canada regulates the methods and compiles the information for the labels, it doesn’t do the testing. That’s left to the auto manufacturers, who follow the government’s test standards in their own facilities and submit the results. If the figures seem sketchy, or if an older model still on the market hasn’t been tested in a while, Natural Resources may do its own audit, using vehicles that it buys at dealerships.
Up until the 2014 model year, Canada used a two-cycle test. Beginning with 2015 vehicles, it ramped up to a five-cycle test similar to the one used by the U.S. since 2008. The two-cycle test is still done, but three more tests were added. It might have looked like the 2015s simply got worse mileage, but in actuality, the new test provided somewhat more realistic numbers.
The two-cycle system consists of a city and highway test, both performed at ambient temperatures of 20°C to 30°C. The city test starts with a cold engine and takes 31 minutes and 14 seconds, with 18 per cent of the total time spent idling. The test covers an equivalent of 17.8 kilometres, at an average speed of 34 km/h, and with a top speed of 90 km/h.
The highway test starts with a warm engine, since most people have to drive to get to a highway, and runs for 12 minutes and 45 seconds. It covers the equivalent of 16.5 kilometres, at an average of 78 km/ h and with a top speed of 97 km/h, simulating a mix of highway and rural road driving.
If those two by themselves don’t sound very realistic, you’re right. The three new tests include one done at -7°C; one at 35°C with the vehicle’s air conditioning running; and a highspeed/quick acceleration test that reaches 129 km/h and with four stops followed by hard throttle.
Compared to the two-cycle test, the five-cycle test produces fuel ratings that are approximately 10 to 20 per cent higher. Natural Resources adjusted the archived figures for all 1995 to 2014 vehicles on its website to bring them in line. For the 2017 model year, some vehicle ratings have also been updated to include the effect of technologies such as hybrid or turbocharged engines.
Conventional engines are rated in the number of litres they consume over 100 kilometres, or L/100 km. That doesn’t work for electric cars, and so they’re rated in “litre equivalent,” or Le/100 km. It’s measured by evaluating electric energy consumption of kilowatt hours per 100 km and converting it to a fuel equivalent, with one litre of gasoline at the energy equivalent of 8.9 kWh of electricity. Plug-in hybrids and extended-range vehicles, which use both gas and electricity, are rated for both.
A few vehicles are exempted from testing, and it goes by weight. These are SUVs and passenger vans with a gross vehicle weight rating (GVWR) of more than 4,536 kg, which is the vehicle’s weight plus its maximum capacity of passengers and cargo, along with vehicles with a curb weight above 2,722 kg or a GVWR of more than 3,856 kg, which includes heavy-duty pickup trucks.
The EnerGuide label shows the vehicle’s tested city and highway fuel consumption, as well as a combined number that’s 55 per cent of its city rating and 45 per cent highway. It also shows an estimated annual fuel cost, based on the vehicle’s tested ratings over 20,000 kilometres driven per year, at an average fuel price of $1.09 per litre.
The 2016 and 2017 labels also show some new items. One includes the best and worst fuel ratings of other vehicles in the segment, without naming them, so buyers can see where it stacks up. New carbon dioxide and smog ratings show where the vehicle’s emissions rate, each on a scale of one to ten, with the tested emissions rated in grams of carbon dioxide per kilometre, or CO2/km. Finally, a QR code can be snapped with a smartphone to access Natural Resources’ online vehicle ratings.
Drivers may find their real-world fuel use differs from the EnerGuide numbers, but the numbers are still useful for comparison-shopping. Of course, fuel consumption also depends on driving habits. To obtain maximum efficiency, drivers should accelerate smoothly, look far ahead to avoid unnecessary hard braking, keep tires at the recommended pressure, and maintain a constant speed, rather than on-the-gas, off-the-gas, on-the-gas as a number of drivers do. It’ll not only improve mileage, but your passengers will be happier, too.