Transient Characterization of Automotive Exhaust Emission from Different Vehicle Types Based on On-Road Measurements

Abstract

Previous works on real-world vehicle emission characteristics have mainly focused on the influences of fuel, speed, vehicle type, elevation, and other factors on vehicle emission quantity and components. However, few studies have investigated the transient trend of automotive exhaust emissions through on-road measurements. The key objective of the present paper was to examine the transient characteristics of exhaust emissions from different vehicle types on the roads of Tianjin. To achieve the goal, a portable emission measurement system (PEMS) was employed to monitor emissions from selected test vehicles—private cars, passenger vehicles, and cargo vehicles. It was found that the high-emission points of test vehicles were mainly distributed in two regions: the high-speed region (speed > 70–90 km/h, vehicle-specific power (VSP) > 0 kW/t) and the medium-speed–acceleration region (20–30 km/h < speed < 60–90 km/h, 0 kW/t <VSP < 12 kW/t). The CO, hydrocarbon (HC), NOx, and particulate number (PN) average emission rates in the high-emission points could be 3.15–14.93 times, 1.93–24.89 times, 3.23–6.03 times, and 3.22–30.27 times of those of average emission rates. The HC, NOx, and PN average emission rates of China IV vehicles in the high-emission points were 2.46–4.92 times, 3.56–6.03 times, and 3.22–13.21 times of those of average emission rates, not less than those of China III (1.93–2.52 times, 2.75–3.90 times, and 9.98–22.34 times). Test vehicles mainly emitted nucleation-mode and Aitken-mode particles, and the increase of the PN concentration emission rate in low-speed and high-speed regions was higher than that in the medium-speed region. The exhaust gas recirculation (EGR) + diesel particulate filter (DPF) could effectively inhibit the Aitken output caused by turbocharged intercooler (CIC). The selective catalytic reduction (SCR) might cause more nucleation-mode particles.

Development of Vehicle Emission Model Based on Real-Road Test and Driving Conditions in Tianjin, China

“…Because the driving state of vehicles in the real road network traffic flow was complex and variable, and there were many factors that affected it, in the modeling process, one or more "surrogate variables" which were closely related to the emission level were usually selected to approximate the driving characteristics of the real road of vehicles [21]. At present, engine load was usually used as a surrogate variable in the mainstream emission models and the most representative engine load parameters was VSP, such as the IVE model [22][23][24] and MOVES model [25,26]. Considering the physical principle of vehicle emission, VSP could better describe the impact of vehicle transient driving characteristics on emission level, so it had higher accuracy [27].…”

Assessment of Gaseous and Particulate Emissions of a Euro 6d-Temp Diesel Vehicle Driven >1300 km Including Six Diesel Particulate Filter Regenerations

“…In most cases, though, the engine and the after-treatment systems calibration was mainly covering the laboratory homologation test conditions but not other conditions typically encountered on the road. On-road calibration has to cover a wide range of ambient conditions (temperature, altitude) and driving events (e.g., speed bumps, traffic, higher vehicle dynamics, altitude) [27][28][29], and is therefore more demanding. The widespread introduction of Selective Catalytic Reduction for NO x (SCR) systems using urea to reduce NO x [30] and proper optimization for a big part of the engine map, has resulted in low NO x emissions.…”

Measurement method of green traffic vehicle exhaust emission based on spark algorithm

“…Based on the above data, this paper constructs a model (Ma et al, 2020) for the determination of green traffic vehicle exhaust emissions in order to realise the determination of green traffic vehicle exhaust emissions. Combined with the exhaust emission factor data, the exhaust emission value of a single vehicle is determined, mapped, superimposed and rasterised, and the total emission value of the vehicle in the driving area is obtained (Lee et al, 2019;Turabimana and Nkundineza, 2020).…”