Majority of the people around the world prefer to buy fuel efficient cars. However, many complain that their cars don’t give as much mileage as mentioned by the car manufacturers. A friend of mine bought a Suzuki Swift, and complained that his car doesn’t do 10-14 KM/L as claimed by Suzuki.
The reason why cars don’t give the mileage listed by their manufacturers, is because the mileage is tested under controlled laboratory conditions. In some countries, the test is conducted continuously for 20 minutes.
The test is split into two cycles, Urban and Extra-Urban Cycle. The Urban Cycle covers 67% of the test, while the extra-urban cycle covers 33%. In the urban cycle, the car is tested in conditions that simulate driving in a city. The car is made to do an average speed of about 19 Km/h with stops and idle periods.
In the Extra-Urban Cycle, the car is made to run at an average speed of about 60 km/h with peak speeds of about 120km/h. This test is carried out to simulate driving on a highway, though it isn’t accurate because the tests are conducted on controlled speeds and for a period of time.
Below is a checklist of a few things that car manufactures check before conducting these tests:
- Tyre pressure and oil viscosity (vary for different car manufacturers)
- Lights and signaling devices are switched off
- The tests are conducted between 20-30 degrees Celsius temperature
- Fuel density is checked (in a few cases)
The reason why a car’s mileage is different from the one claimed by manufacturer includes the factors like, wind, extra weight, air condition and other variables that affect the car on the road. These variables are not taken into account during the laboratory test. This why, real life mileage differs from the mileage indicated by manufacturers.
Do share your experience on the fuel efficiency of your car. Does the manufacturer of your car satisfy your expectations?