Influences of Crest Vertical Curve Curvature on Exhaust Emissions of Heavy-Duty Diesel Trucks at Grade Change Point Section in Highway

Xingli Jia,Xingpeng Chen,Xuefang Qin,Wuxiao Zhou,Shuangqing Li

doi:10.3390/en15041506

Abstract

The vertical curve is a major factor affecting vehicle exhaust (CO2, CO, NOx, PM2.5) emissions. This article takes a heavy-duty diesel truck as a typical vehicle, combining instantaneous speed, acceleration and the vehicle-specific power VSP to divide the operating mode, and the exhaust emission of a heavy-duty diesel truck is then calculated by using MOVES. Finally, the environmental modification factors (EMFs) are used to evaluate the influence of curvature change on the exhaust emissions. The results show that CO2 and PM2.5 emissions of heavy-duty diesel trucks are increasing with the curvature of the crest vertical curve changing; with the increase and decrease of curvature K of the crest vertical curve by 50%, CO and NOx emissions showed an increasing trend. Among the four main emissions, CO2 emission amount is the largest, followed by NOx, CO and PM2.5. The emission rates of CO2 and PM2.5 increase with the increase of curvature of the crest vertical curve, and the minimum values of CO2 and PM2.5 emission rates are 46.7 g/s and 0.022 g/s, respectively. The emission rates of CO and NOx increase with the increase of curvature. The minimum point of emission rates of CO and NOx are 0.042 g/s and 0.259 g/s, respectively.

Highlights

Introduction in HighwayEnergies 2022, 15, 1506.Vehicle exhaust pollution is becoming one of the main issues of widespread international concern
The results found that the effects of altitude, vehicle speed, engine speed, and load on the emissions of various pollutants
In the design of a variable slope point, the curvature of a crest vertical curve should be greater than or equal to the minimum standard stipulated in the Green Book

Summary

Introduction

Vehicle exhaust pollution is becoming one of the main issues of widespread international concern. Since most diesel vehicles are not equipped with an exhaust post-treatment system [1], diesel engines emit more pollutants and have more impact on air pollution by [2]. The internal combustion engine exhaust of diesel vehicles mainly comes from incomplete combustion of fuel. Its main pollutants are particulate matter (PM), COx , NOx and hydrocarbons (HCs) [3]. When diesel engine cars are driving in the variable slope point section, more fuel consumption is needed to maintain the running state, and emit more exhaust gas relative to the flat slope section [4,5]. Some research shows that the vertical curve change affects the emission control of various diesel vehicles [6,7,8]

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