YEN JUNG, H. and Lu, J., "Regeneration of DPF with a bypass passage ," SAE Technical Paper 2017-01-1722, 2017.
There is a growing concern for the pollutants emitted by diesel vehicles, especially the World Health Organization (WHO) officially classified diesel engine exhaust as a carcinogen. Countries all over the world have formulated stringent standards to regulate the emissions of new diesel engines. However, diesel engines are very durable that 60% of the diesel vehicles are more than ten years old in Taiwan. In order to reduce the exhaust emission of these in use vehicles, installation of diesel particulate filter (DPF) is currently promoted. As the carbon particulates accumulate inside the filter to a certain amount, the DPF needs to be regenerated to prevent clogging of the filter. It was found the regeneration process may cause “second pollution” and generate hot exhaust that might cause disasters when the regeneration is conducted as the vehicle is parking. A low-cost technology, using a bypass valve system during generation, was proposed in this study as a solution to abate the second pollution and reduce the exhaust temperatures. Different bypass ratios up to 50% were tested in this study. It was found the NOx produced during the regeneration process decreased slightly. The opacity of the exhaust flue gas was reduced by 30%. The mass concentration of PM2.5 was reduced by 50%. The regeneration efficiency slightly declined, but still within the acceptable range. keyword：diesel engine、diesel particulate filter、second pollution、bypass system.