Cold-start conditions are responsible for most vehicle tailpipe emissions. The present study introduces a novel method for trapping cold-start emissions. A numerical model is used to examine the effect of the method's implementation on cold-start emissions. Experiments are used to validate the model. In order to understand the effects of the employed method, three different driving cycles are simulated. The results show that the light-off temperature is independent of the driving cycle, whereas the light-off time is highly dependent on driving behavior. The presented concept is more effective for traffic conditions and the vehicle's low power requirements. Emission reductions are the greatest after catalyst light-off when there is a moderate increment. The most notable reduction is in NOx emissions in all driving conditions, while CO reduction is not as beneficial as NOx. CO emissions are reduced from 20%(WLTC) to 35%(NEDC), HC emissions are reduced from 25%(WLTC) to 34% (NEDC and FTP75), and NOX emissions are reduced from 41%(FTP75) to 51% (NEDC). The components of the presented concept were then designed using a systematic approach in the present study. A prototype can be built using a variety of compressors, reservoirs, and control strategies for releasing trapped gas. To prioritize the effective parameters of concept execution in the vehicle, the analytical hierarchy process approach is implemented. Based on the available prototyping options, twelve different scenarios can be identified. The emission reductions of different strategies are also eva‎luated using a validated GT-Suite model. The best scenario is then built and tested during the urban part of the NEDC driving cycle. For the prototype, a 10-liter reservoir with a compressor at 10 bar was selected. When the vehicle stops during driving, the trapped emissions are released from the reservoir. Cold-start emissions significantly decrease after method implementation, while the emission trend after cold-start is similar to the base vehicle's. Based on the results, more emissions production after cold-start reduces the benefits of concept application for emission reduction. As a result of the experiments, CO, HC, and NOx levels decreased by 4, 20, and 12 percent, respectively. With this idea, gasoline-powered vehicles would be able to pass more strict emission standards, such as Euro7, in the future.

ايمان چيت‌ساز

محسن دوازده‌امامي

رامين كوهي كمالي، احمد سوهانكار