Study of Real-road Nitrogen Oxide Emissions of Non-road Vehicles

The exhaust gas pollutants of the non-road vehicles are harmful to the environment. Many non-road vehicles meet the requirements of the regulations in the laboratory. However, the real-road emissions of such vehicles are sometimes higher. Measuring the real-road emissions of non-road vehicles is very important. The real-road emissions are measured by on-Board Diagnostics (OBD), but there are some problems in the data stability of OBD. The NOx emissions of a bulldozer (a type of China IV non-road vehicle) based on both portable emission measurement system (PEMS) and OBD are studied in this article. Experiments contained three working processes: idle, driving, and operating. The nitrogen oxide (NOx) emissions during operating were highest. The NOx emission characteristics of the bulldozer from PEMS and OBD have the similar variation trends. But there are still some differences, including the NOx emission value and response time. The measurement principles and different sampling points between PEMS and OBD are the main factors. An effective data processing method is introduced to reduce the differences of between the data from PEMS and OBD. Briefly, the NOx emissions of the OBD and PEMS were highly consistent. The OBD is reliable and can be widely used in non-road vehicles.

Real Driving NOx Emission Measurements of Vehicles with ICAD instruments for Plume Chasing

<p>Nitrogen Oxide (NO<sub>x</sub>) emissions from vehicles are a major cause of poor air quality in urban areas. The emissions per vehicle are regulated by the EURO Norm (EURO V: 2000mg/kWh, EURO VI: 460mg/kWh). Existing possibilities to measure whether the vehicles comply with the regulations (e.g. PEMS: Portable Emission Measurement System) are rare and costly. Within the framework of the EU project CARES (City Air Remote Emission Sensing) different remote emission sensing techniques and instruments are further developed. ‘Plume Chasing’ is one of them. With the Plume Chasing method, the emissions of a vehicle are measured in the wake of the investigated vehicle, i.e. in the diluted emission plume. This is done with a for this purpose optimized ICAD NO<sub>x</sub>-CO<sub>2</sub> instrument (Airyx GmbH), that allows fast (1s time resolution) and simple measurements with high accuracy (sub ppb for NO<sub>x</sub>) with a high measurement range (0-5000ppb). With these characteristics, it is perfectly suitable to detect malfunctioning or illegally manipulated emission control systems like SCR (selective catalytic reduction).</p><p>Several validation studies of Plume Chasing against the established PEMS have shown very good correlations. During a 3-day study in Sweden in November 2019, Plume Chasing measurements of a EURO V and a EURO VI truck were performed with activated as well as deactivated emission control system for several hours in different driving conditions. The derived Plume Chasing NO<sub>x</sub> emission values even for short measurement times of one and two minutes showed excellent correlation with the averaged PEMS NO<sub>x</sub> data of the trucks with R<sup>2</sup>~0.9. The study demonstrated the robustness of the Plume Chasing method in detecting high emitter trucks. To further test and optimise different measurement configurations and data analysis algorithms, within the CARES project several ICAD NO<sub>x</sub>-CO<sub>2 </sub>instruments are installed together with e.g. LICOR CO2-sensors or Condensation Particle Counters in a measurement vehicle from TNO, Netherlands.</p><p>Studies on German and Austrian highways in 2018 and 2019 showed that among several hundreds of trucks up to 35% of the EURO V trucks and up to 25% of the EURO VI trucks showed consistently high emissions exceeding the EURO norm limit, which provides strong evidence for a high number of defect or manipulated emission control systems. A recent study in Denmark showed 9,7% of the vehicles exceeding the standards. The vehicles were afterwards inspected by the police and defects or manipulations of the emission control system could be confirmed.</p>

Emission Measurement of Buses Fueled with Biodiesel Blends during On-Road Testing

Increasing the biodiesel content of diesel fuels is encouraged because of its reduced carbon footprint. Pure rapeseed methyl ester (RME)and used cooking oil methyl ester (UCOME) are characterised by well-to-tank greenhouse gas (GHG) reductions of 54% and 88% compared to pure B0 petrodiesel, respectively. Captive fleets such as public transport buses could benefit from these GHG reductions by increasing the biodiesel content of their fuel because they have a consequent yearly fuel consumption. The aim of this paper is to compare on-road tailpipe emissions of a diesel bus when increasing the biodiesel concentration in the fuel. The tests were carried out on a standard city bus belonging to the Euro V EEV emission standard that was equipped with a portable emission measurement system measuring NO, NO2, PN, CO and CO2 at the tailpipe. The bus followed the SORT which is representative of urban bus driving. The heavy urban on-road measurements indicated increased NOx emissions (24–26%), decreased PN emissions (43–45%) and slightly decreasing CO emissions for B30 RME and UCOME compared to B7. A measurement uncertainty analysis showed that the CO emissions were less reliable. Similar conclusions were drawn for the easy urban on-road bus emission measurements with smaller differences between B7 and B30 RME and UCOME.

The impact of parameter modifications in the Diesel engine power system on the emissions of harmful compounds

The article presents the results of emission tests and vehicle operation indicators fueled with diesel oil. The tests were carried out for a passenger vehicle equipped with a diesel engine meeting Euro 3 emissions standard, moving in urban traffic. The measurements were carried out using modern PEMS (Portable Emission Measurement System) enabling the emission of gaseous components from exhaust systems of the tested object. On the basis of the conducted tests, the load characteristics were determined using the torque values obtained along with the engine speeds. The measurement route included two cycles: urban driving and fast acceleration. The aim of the study was to assess the impact of modifications to the control maps on CO, CO2, PM and NOx exhaust gas emissions under real operating conditions.

Real time estimation of emissions in a diesel vehicle with neural networks

Several studies in literature have shown how real-world emissions strongly depend on driving condition, driving style, ambient temperature and humidity, etc. so that they are significantly different from the values measured on test benches over standard driving cycles. This concern, together with the so-called Diesel-gate, has caused the introduction in Europe of an innovative procedure for the registration of vehicle based on real driving emissions (RDE) measured with a portable emission measurement system (PEMS). PEMS devices are bulky and very expensive, therefore they cannot be extensively for an actual real time monitoring of emissions. To solve this problem, the present work proposes a Neural Network model based on the interpolation of the time-histories of driving conditions (speed, altitude, ambient temperature, humidity and pressure) and emissions measured on a diesel start-and-stop vehicle while performing a series of RDE tests. Two different approaches are proposed. The first one calculates the emissions on the basis of the vehicle motion (speed and altitude profile, ambient conditions). The second one models the engine block using as input the ambient conditions, the load and the rpm of the engine as derived from the OBD-II scanner. The output of both models are the flow rates and cumulated values of CO2 and NOx. Note that the inputs of the two models are signal that can easily obtained on-board without additional sensors.

Impact of the use of comfort devices on the exhaust emission from a hybrid vehicle

Vehicles are equipped with more and more devices to improve the comfort of traveling. They are usually powered by electricity generated by the engine, which translates into an increase in its loads and, as a consequence, fuel consumption and emission. However, there is no information about the possible increase in the amount of other harmful components contained in the exhaust gases. Often this result is inadequate to that obtained during the operation of the vehicle, where the obtained fuel consumption is higher. As part of this article, tests were carried out in real hybrid vehicle traffic conditions on the same test route using an analyzer from the PEMS (Portable Emission Measurement System) ¬ SEMTECH DS Sensors Inc. The analysis of gaseous components of exhaust gases together with the exhaust mass flow probe and the GPS system made it possible to calculate the pollutant emission.. On this basis, the actual mileage fuel consumption of the tested vehicle was calculated using the road emission of carbon-containing compounds (carbon balance method).

Comparison of exhaust emission from Euro 3 and Euro 6 motor vehicles fueled with petrol and LPG based on real driving conditions

Constantly increasing requirements regarding emission limits for harmful exhaust components force vehicle manufacturers to im-prove the construction of vehicle engines as well as exhaust gas cleaning systems. In addition to modifications in the field of technology of motor vehicles themselves, it is also important to study the impact of alternatives to petrol or diesel fuels. One of the most popular fossil fuel is liquid petroleum gas. In the paper, the results of comparative studies on the emission of harmful exhaust components of vehicles meeting the Euro 3 and Euro 6 standards in the field of petrol and LPG fuel use are presented. Emission measurement was performed using a portable emission measurement system from Horiba OBS-2200 under real traffic conditions. The presented results show the differences between the tested vehicles and the fuels used.