Engine cold start analysis using naturalistic driving data: City level impacts on local pollutants emissions and energy consumption

• Published in: The Science of the total environment 2018-07, Vol.630, p.544-559
• Main Authors: Faria, Marta V., Varella, Roberto A., Duarte, Gonçalo O., Farias, Tiago L., Baptista, Patrícia C.
• Format: Article
• Language: English
• Subjects: Ambient temperature; Cold start; Emissions; Energy consumption; Vehicle specific power
• ISSN: 0048-9697; 1879-1026
• DOI: 10.1016/j.scitotenv.2018.02.232

The analysis of vehicle cold start emissions has become an issue of utmost importance since the cold phase occurs mainly in urban context, where most of the population lives. In this sense, this research work analyzes and quantifies the impacts of cold start in urban context using naturalistic driving data. Furthermore, an assessment of the influence of ambient temperature on the percentage of time spent on cold start was also performed. Regarding the impacts of ambient temperature on cold start duration, a higher percentage of time spent on cold start was found for lower ambient temperatures (80% of the time for 0°C and ~50% for 29°C). Results showed that, during cold start, energy consumption is >110% higher than during hot conditions while emissions are up to 910% higher. Moreover, a higher increase on both energy consumption and emissions was found for gasoline vehicles than for diesel vehicles. When assessing the impacts on a city perspective, results revealed that the impacts of cold start increase for more local streets. The main finding of this study is to provide evidence that a higher increase on emissions occurs on more local streets, where most of the population lives. This kind of knowledge is of particular relevance to urban planners in order to perform an informed definition of public policies and regulations to be implemented in the future, to achieve a cleaner and healthier urban environment. [Display omitted] •Extensive real world data collection to evaluate vehicle cold start running.•Assess the impacts of cold start running on the city perspective.•Lower average ambient temperatures increases the cold start running duration.•Increase of 110% on energy consumption and up to 910% on emissions for cold start.•The impact of cold start is higher on more densely populated areas.