Study: gasoline direct-injection engines emit many particles

According to a study by the Bern University of Applied Sciences, gasoline engines with direct injection emitted a particularly large number of hazardous particles. The current study shows that emissions in real traffic are significantly higher than in the test lab. Deutsche Umwelthilfe (DUH), which commissioned the study, is therefore calling for the installation of filters like those in diesel engines.

Gasoline engines with direct injection emit significantly more harmful particles in traffic than in laboratory tests. With a realistic driving behavior, the emission of pollutants rose sharply in the test. "This can be easily remedied by car manufacturers installing a particulate filter, as they do with diesel," says Dorothee Saar, an expert on air pollution control at DUH. A Hyundai 30 GDI with 1.6 liters and a VW Golf VII TSI with 1.4 liters were tested. The Volkswagen complied on the test bench with the limits for particulate emissions applicable from 2014 and from 2017. The Hyundai was only below the weaker 2014 limits. On the road, however, the Golf’s emissions were significantly higher than those of the Hyundai. In the second run with particulate filter, the emissions of the Golf were almost completely reduced.

In Dorothee Saar’s opinion, the laboratory test is simply not comparable with the behavior of drivers in real traffic. On the road, for example, significantly higher top speeds and stronger accelerations were achieved. Simply put: Hardly anyone has a driving style as mabful as that simulated in the lab.