Characterization of Exhaust CO, HC and NOx Emissions from Light-Duty Vehicles under Real Driving Conditions

Abstract

On-road exhaust emissions from light-duty vehicles are greatly influenced by driving conditions. In this study, two light-duty passenger cars (LDPCs) and three light-duty diesel trucks (LDDTs) were tested to investigate the on-road emission factors (EFs) with a portable emission measurement system. Emission characteristics of carbon monoxide (CO), hydrocarbons (HC) and nitrogen oxides (NOx) emitted from vehicles at different speeds, accelerations and vehicle specific power (VSP) were analyzed. The results demonstrated that road conditions have significant impacts on regulated gaseous emissions. CO, NOx, and HC emissions from light-duty vehicles on urban roads increased by 1.1–1.5, 1.2–1.4, and 1.9–2.6 times compared with those on suburban and highway roads, respectively. There was a rough positive relationship between transient CO, NOx, and HC emission rates and vehicle speeds, while the EFs decreased significantly with the speed decrease when speed ≤ 20 km/h. The emissions rates of NOx and HC tended to increase and then decrease as the acceleration increased and the peak occurred at 0 m/s2 without considering idling conditions. For HC and CO, the emission rates were low and changed gently with VSP when VSP < 0, while emission rates increased gradually with the VSP increase when VSP > 0. For NOx NOx emission rates were lower and had no obvious change when VSP < 0. However, NOx emissions were positively correlated with VSP, when VSP > 0.

A Deep Learning Micro-Scale Model to Estimate the CO2 Emissions from Light-Duty Diesel Trucks Based on Real-World Driving

“…These vehicles were both in good working conditions with odometer readings of 28,918 km and 94,080 km respectively. More specifications for these test vehicles can be found in our previous study [34]. The fuel used in this study was directly purchased from a local gas station and met the corresponding Automobile diesel fuels (China VI) (GB19147-2016).…”

“…Other regulated gaseous pollutants (CO, HC, NOx) were also tested at the same time. This paper only focused on the emission characteristics and the prediction of the CO 2 emissions, and more details can be found in reference [34]. A global positioning system (GPS) was used to record the instantaneous longitude, latitude, and velocity of the vehicle during the test with a spatial resolution of 10 m and velocity of ±1 km/h, respectively.…”

Characteristics of Suspended Road Dust According to Vehicle Driving Patterns in an Urban Area and PM10 Content in Silt

“…In studies of exhaust gas, however, engines powered by modern diesel and compressed natural gas (CNG) showed the lowest PM concentrations and toxicological responses compared to other engine types [11]. Furthermore, there was a roughly positive relationship between transient CO, NOx, and HC emission rates and vehicle speeds, while the emission factors (EFs) decreased significantly with a speed decrease when the speed was ≤20 km/h [12]. With the grade of the road, the emission rates of NOx and HC tended to increase, and then, decrease as acceleration increased, peaking at 0 m/s 2 without considering idling conditions.…”

“…However, most studies related to exhaust gas have measured the concentration of carbon dioxide or PM, by conducting indoor experiments. But there has been a lack of research considering the various patterns that may occur in the city center or examining the effects of the difference in concentration occurring when a vehicle is actually driving at a constant speed [11,12]. Therefore, through this study, we tried to make this differentiation ourselves by identifying the dust concentration level that pedestrians passing by a road may be exposed to, the effective distance between the vehicles, and the correlation with silt loading and suspended road dust.…”

Editorial for the Special Issue “Impacts of Transport Systems on Air Pollution and Human Health”

“…This global vision should apprehend all aspects without harming the economy, employment and people's way of life, and furthermore, should be more effective and should be shared through international networks. Regulations, the technological development of transportation systems and their management should meet the challenges of this ongoing energy transition [1][2][3][4][5][6][7][8][9].…”