Easy ways to improve fuel efficiency
The gap between fuel economy you get in the real world and the official figures that automakers must include in their brochures was to wider and wider.
In 2001, the average difference was relatively small, 8 in 2014 has increased to 40.
Some difference is to be expected as a laboratory test can never accurately reflect the range of driving style, road and weather conditions in the real world, but the gap is so great that manufacturers have been accused of misleading statements .
It seems that the car is running more economical, on paper, the greater the gap between official figures and actual fuel consumption This means that you can not even rely on official figures as a guide to relative performance.
New car models must meet a series of safety tests and certification of the environment before they can be sold.
Such a test is to determine the official fuel consumption and data on CO2 emissions.
The car's driven on a rolling road after a defined cycle.
Car manufacturers must indicate the official fuel consumption figures and aren t allowed to mention other figures.
The official CO2 figure is the basis of our tax system drive and is used by the European Commission to monitor CO2 fleet average and progress towards emissions reduction goals.
European countries must meet strict targets for CO2 emissions average 130g Park 2015 km and 95g km 2020 Heavier cars are allowed higher emissions if offset by lighter vehicles with lower emissions.
Car manufacturers have a strong financial interest that fines for exceeding the CO2 targets can be considerable.
The official test takes place on a laboratory rolling road and currently follows the so-called new European NEDC driving cycle which consists of two parts of an urban cycle an extra-urban cycle.
Urban cold start followed by about 2 5 miles at an average of 12 mph to briefly reach a maximum of 31 mph.
Following the extra-urban law urban cycle, car covers 4 3 miles at an average of 39 mph.
Three fuel consumption figures are calculated in urban, extra-urban and combined figure is a weighted average of the other two.
The basic test cycle was developed in the 1970s and doesn t represent good modern behavior patterns or vehicle performance.
The cycle is only short-lived and dominated by periods of idling and low engine load.
Air conditioning, lighting and other electrical loads are switched off for the test.
Flexibilities in the testing procedure can be exploited to achieve an overall lower fuel consumption.
The test is performed in an ambient temperature of between 20 and 30 C much higher than the average outdoor temperature.
The manner in which the rolling resistance of the rollers is adjusted in discrete steps means that a small reduction in vehicle weight can be sufficient to obtain a significant reduction in rolling resistance.
Fuel consumption can be optimized for the test conditions.
The test can give a distorted view of the benefits of new technology start-stop systems work well in the test, because it contains a lot of idling about 10 NEDC.
Doesn t test accommodate passengers or other charges.
A new global driving cycle, the light of worldwide test cycle WLTC was developed by experts from Europe, India and Japan with the United States and China as observers.
In Europe, the new testing procedures based on WLTC should be used from 2017.
The change in NEDC WLTC will result in an increase in fuel consumption and CO2 emissions by about 5 Changes to the test procedure, setting up vehicle and operating conditions will have an effect too.
The fleet average target manufacturers CO2 emissions of 95g km 2020 should be modified because it has been put under the NEDC plan.
European regulations require toxic exhaust emissions effectively limit in normal driving and throughout the normal life of the vehicle rather than in standard laboratory tests.
To do this, a new test of actual emissions driving RDE is introduced alongside the new laboratory test.
RDE uses a measurement system mobile emissions PEMS that measures NOx, CO and soot particles on a vehicle when it's driven on normal roads in a range of conditions.
The new test RDE apply to all new models from September 2017 and to all new vehicles from September 2019.
RDE is a relatively severe test and emission limits higher compared to apply laboratory test WLTP A so-called compliance factor will be applied in two steps.
Step 1 RDE emissions can be up to 2 times higher than 1110 from September 2017.
Step 2 emissions RDE can be up to 1 5 times 50 more than in January and new models 2,02 thousand in January 2021 all new cars.
If you assume the fuel economy of about 40 less worse than the official combined figure quoted by the manufacturer, you should not be disappointed, and perhaps pleasantly surprised.
If you are looking for a used car in the gap depend on the age of the vehicle about 10 car 10 years to about 25 for a car that is aged 3 to 5 years.
Every single test is defective and not a single pilot is representative of everyone, but if you could see what kind of fuel economy many of the other drivers get in the same car that will give you a fair idea of what can be achieved by taking your own driving style into account.
Honest John MPG real users have downloaded more than 100,000 fuel consumption figures average 84 cars reach the figure of the official combined fuel consumption but this includes many older models when the test was more representative.
A German site that calculates fuel economy based on users buy fuel and fuel consumption data mileage figures are given in liters 100 km instead of miles per gallon to convert liters 100 km mpg divide 62 by 15 fuel consumption in the 100 km and multiply by 4546.
AA Official fuel consumption figures, official, the fuel consumption figures.