An experimental study to investigate typical temperature conditions in fuel tanks of European vehicles

Abstract

Vehicular evaporative emissions have been recognized as an important source of volatile organic compounds to the environment and are of high environmental concern since these compounds have been associated to the formation of surface ozone and secondary organic aerosols. Evaporative emissions occur during any vehicle operation. In Europe, a revised legislative test procedure has been recently introduced to better control evaporative emissions during parking. However, emissions related to normal driving conditions—the so-called running losses—have received less attention compared with the other categories. The current study aims at giving some insights to the prevailing temperature conditions in fuel tanks of typical European vehicles during normal driving operation. The effects of ambient air temperature, trip duration, vehicle speed, and fuel tank level on the temperature reached by the fuel inside the tank under different real-world operating conditions were studied. Tank temperature can exceed 40 °C depending on ambient and driving conditions. Ambient temperature was found to be the most important parameter affecting the tank temperature. Trip duration and driving pattern may also have an influence on the tank temperature particularly when long trips combined with high vehicle speed are examined. Additionally, the difference between tank and ambient temperature was examined during the individual trips and was found to vary between 1 and 10 °C depending on the testing conditions. The most important parameters affecting the delta temperature were found to be the trip duration and the maximum vehicle speed. Finally, the purging strategy of two of the test vehicles was monitored, and the parameters affecting the purging flow rate were investigated. No strong correlation between the canister flow rate with ambient temperature, vehicle speed, or fuel level was observed in either of the tested vehicles. Substantially different canister flow rate levels between the two vehicles point to different purging strategies. Electronic supplementary material The online version of this article (10.1007/s11356-019-04985-7) contains supplementary material, which is available to authorized users.

Effectiveness of emissions standards on automotive evaporative emissions in Europe under normal and extreme temperature conditions

“…It should be noted that refueling emissions have traditionally not been considered within automotive evaporative emissions inventories and regulations in Europe; instead, refueling emissions are classified with the distribution of oil and gas products [15]. This has historically led to the belief that evaporative emissions from vehicles are of the same magnitude as exhaust emissions; in reality, the evaporative component can be significantly larger when refueling emissions are included [5,6]. In this study, refueling emissions are attributed to and considered part of the evaporative NMVOC emissions from passenger ICE vehicles, which also includes running losses such as leaks, permeation, and diurnal losses.…”

Improvement of the Theoretical Model for Evaluating Evaporative Emissions in Parking and Refueling Events of Gasoline Fleets Based on Thermodynamics

“…The present study focuses on the DBL and RFL as they are one of the major sources of VOCs from evaporative emissions of gasoline vehicles and are regulated in many countries. These two emission processes are described in this section, whereas previous studies can be referred to for the remaining three evaporative emissions. − The DBL is an evaporative emission from a fuel tank due to a diurnal temperature change during parking events and can be divided into permeation and breakthrough emissions. Permeation is the evaporative emission from fuel-related parts.…”

Evaluation of Gasoline Evaporative Emissions from Fuel-Cap Removal after a Real-World Driving Event

“…Evaporative emissions result from fuel-based VOC evaporation in gasoline vehicles; further, these emissions can be attributed to running losses, hot-soak losses, diurnal breathing losses, refueling emissions, and puff losses. Previous studies have comprehensively examined the different mechanisms underlying evaporative emissions [15][16][17][18][19][20][21]. However, few studies have focused on puff loss emissions, which have been deemed as potentially significant atmospheric pollutants by the US Environmental Protection Agency [22].…”