Adjusted fuel consumption ratings: All you need to know

As you know, the current fuel consumption ratings are difficult to achieve for most drivers, even with moderate use of the throttle and air conditioning.

Therefore, Natural Resources Canada (NRC) recently announced a new protocol to determine fuel consumption ratings, starting with 2015 model year vehicles. This way, the average driver will have a better idea of much fuel they can expect to burn day in, day out.

Current testing
Fuel consumption ratings are derived from the emissions generated during two laboratory driving cycles: a city test and a highway test.

According to NRC, the city test simulates urban driving in stop-and-go traffic with an average speed of 34 km/h and a top speed of 90 km/h. The test runs for approximately 31 minutes and includes 23 stops. It begins from a cold engine start, which is similar to starting a vehicle after it has been parked overnight during the summer.

The final phase of the test repeats the first eight minutes of the cycle, but with a hot engine start. This simulates restarting a vehicle after it has been warmed up, driven, and then stopped for a short time. Over five minutes of test are spent idling to represent waiting at traffic lights.

Meanwhile, the highway test simulates a mix of open highway and rural driving, with an average speed of 78 km/h and a top speed of 97 km/h. The test runs for approximately 13 minutes and does not include any stops. It begins from a hot engine start.

The fuel consumption values derived from these test cycles are then adjusted upwards by 10% (city) and 15% (highway) to more accurately reflect real-world driving.

New testing
Here, the standard 2-cycle test program is supplemented with three additional tests that account for cold temperature operation, air conditioning usage, and higher speeds with more rapid acceleration and braking. This 5-cycle testing procedure better approximates typical driving conditions and behaviours.

In the cold temperature operation test, the same driving cycle is used as in the standard city test, except that the ambient temperature of the test cell is set to -7

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