|The tougher JC08 test cycle and the older 10-15 cycle. Click to enlarge. Source: ICCT, “Passenger Vehicle Greenhouse Gas and Fuel Economy Standards”|
The Prius has become the first car to meet Japan’s new 2015 Fuel Economy Standards, with testing under the new JC08 test cycle.
In December 2006, Japan revised its existing fuel economy standards—which are weight-based—upwards and increased the number of weight bins from nine to sixteen. The JC08 test cycle—which is longer, has higher average and maximum speeds, and requires more aggressive acceleration than the older 10-15 cycle—is due to be introduced in 2010 and will apply to meeting the 2015 standards.
According to the Japanese government, JC08 will increase the stringency of the testing by about 9%, making the new 2015 standards even more exacting compared to the existing standards, for which the 10-15 cycle is used.
The results of the Prius testing reflected the tougher new test cycle: fuel economy under JC08 came to 26.9 km/l (3.7 l/100km or 63.3 mpg US). Under the 10-15 test cycle, the Prius returned 35.5 km/l (2.8 l/100km or 83.5 mpg US). The 2015 target for the Prius weight category (Class 7: 1,196 - 1,310 kg) is 17.2 km/l (5.8 l/100km or 40.5 mpg US).
|Japanese 2015 fuel economy targets. Click to enlarge.|
A recently published comparison of global fuel economy standards by the International Council on Clean Transportation (ICCT) notes that under the JC08 test, the average fuel economy for the Japanese MY2004 fleet would have been approximately 13.6 km/l (7.4 l/100km or 32 mpg US). The new standard is expected to raise that to 16.8 km/l (6.0 l/100km or 39.5 mpg US), an increase of 23.5%.
The 2015 fuel economy targets range from 22.5 km/l (4.4 l/100km or 52.9 mpg US) for vehicles weighing less than 600 kg up to 7.4 km/l (13.5 l/100km or 17.4 mpg US) for vehicles weighing more than 2,271 kg.