Comparison of vehicle emissions in the scope of laboratory and real driving tests

Exhaust emissions released by road vehicles into the air have become an issue that has an increasing negative impact on human health and therefore needs to be controlled. Vehicle emissions control and emission measurements are among the most emphasized topics in the automotive industry today; and emission tests, which are kept under control with emission regulations, are critical for automobile manufacturers. However, laboratory tests that measure emissions with constant cycles in a standard environment, which have been used for years, do not give realistic results in representing the real driving conditions of the automobile users. For this reason, in recent years, tests that measure the emissions of vehicles under real road conditions have become as important as laboratory tests, and studies have shown that they can replace laboratory tests in the future. Apart from the advantages of real driving emissions (RDE) tests, it also poses different challenges for automotive manufacturers. RDE tests are more comprehensive and longer than laboratory tests, the risks that may be encountered in real road conditions while performing the test, the inability to test in difficult road and weather conditions, and the waste of effort and time in possible test cancellations, the use of more compact emission measuring devices and these devices are more sensitive and difficulties such as being more difficult to use. Within the scope of the thesis, the representation of RDE tests in laboratory conditions was examined in order to overcome these difficulties. For this purpose, RDE tests performed under real road conditions with a reference gasoline vehicle were repeated under laboratory conditions and the results were analyzed comparatively. In other words, it has been investigated whether there is a significant correlation between laboratory tests and real road tests. If this is possible, it will be possible to accurately estimate the actual road values from the results of the laboratory tests, and all of the real road test difficulties mentioned above will be avoided. Emission factors are calculated for each emission gases in the results of the comparative tests. Emission factors were found between 0.92 - 1.75 for nitrogen oxides (NOx), 0.81 - 1.21 for carbon monoxides (CO), and 1.04 - 1.15 for carbon dioxide (CO2). As a result of the obtained results, it was interpreted under which conditions and how RDE tests can be represented in the laboratory environment.