When consumers decide to buy a new car, environmental performance of a car has now become one of the key factors to consider apart from price, driving performance and comfort.
The latest issue of CHOICE magazine (No. 435) published a car review report containing comprehensive information for consumers' reference. The report presented the results of road tests on the performance of the tested cars, as well as tests on their fuel consumption level and pollutant emissions which were conducted in a laboratory using controlled scientific methods.
The tests were conducted by the International Consumer Research & Testing (ICRT) and an automobile association in Europe, covering a total of 20 models from 9 different brands. The tested models included 8 large family cars, 7 small family cars, 4 executive cars and 1 supermini.
To assess the environmental performance of the tested samples, driving cycle tests were conducted in the laboratory, which simulate urban, countryside and motorway driving, in order to measure the energy efficiency, and emissions of carbon dioxide and pollutants. In some of the tests, the air conditioning system of the tested models was turned on to mimic authentic driving scenario.
On fuel consumption, the test measured the fuel consumed in each driving cycle, and then calculated the average fuel consumption.
In the small family car category, the difference was 56% when the sample with the highest average fuel consumption, or AFC, (9.5 litres per 100 km) was compared to the sample with the lowest AFC (6.1 litres per 100 km).
In the large family car category, a difference of 65% was found among the sample with highest AFC (10.2 litres per 100 km) and the sample with lowest AFC (6.2 litres per 100 km).
The samples with the highest average fuel consumption, in both large and small family car groups, were poorly rated in their energy efficiency, scoring only 1 point in a 5-point scale.
Carbon dioxide is recognized as one of the gases causing greenhouse effect, which in turn leads to global warming. Therefore the vehicles with less carbon dioxide emissions are the better.
The test results showed that a sports car styled sample in the small family car category recorded 60% higher in carbon dioxide emissions as compared with that of the best sample (except electric car) in the same category.
In addition to measuring the carbon dioxide emissions directly, the test organizations modified the method to assess pollutant emission in some of the tested cars. The revised method also considered the level of carbon dioxide generated either by a refinery in producing the petrol, or generated by a power plant in producing electricity, which is included for a certain sample to run for each kilometer. The result indicated that 3 samples (including a hybrid car) had higher total carbon dioxide emissions.
One sample, which is an electric car, does not emit carbon dioxide when it runs. Test findings showed its emission is still the lowest among the samples even after including carbon dioxide emitted from the power plant during the production of (required level of) electricity for the electric car sample.
Emission of other pollutants such as carbon monoxide, hydrocarbons, nitrogen oxides and suspended particulates was measured in the driving cycle test of the samples, except the electric car which does not emit pollutants. During the driving cycle tests of most of those samples, a relatively low level of such pollutants was recorded. However, a hybrid vehicle sample in the executive car category produced relatively high emissions of pollutants in the driving cycle test, scoring 3.5 points in a 5-point scale.
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- 2013.01.15