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Technical Paper

Proceedings of Real Driving Emission (RDE) Measurement in China

2018-04-03
2018-01-0653
Light-duty China-6, which is among the most stringent vehicle exhaust emission standards globally, mandates the monitoring and reporting of real driving emissions (RDE) from July, 2023. In the process of regulation promulgation and verification, more than 300 RDE tests have been performed on over 50 China-5 and China-6 certified models. This technical paper endeavors to summarize the experience of RDE practice in China, and discuss the impacts of some boundary conditions (including vehicle dynamic parameters, data processing methods, hybrid propulsion and testing altitude) on the result of RDE measurement. In general, gasoline passenger cars confront few challenges to meet the upcoming RDE NOx requirement, but some China-5 certified samples, even powered by naturally-aspirated engines may have PN issues. PN emissions from some GDI-hybrid powertrain systems also need further reduction to meet China-6 RDE requirements.
Journal Article

Investigation of Combustion and Emission Performance of Hydrogenated Vegetable Oil (HVO) Diesel

2017-10-08
2017-01-2400
Hydrogenated Vegetable Oil (HVO) diesel fuels have the potential to provide a reduced carbon footprint for diesel engines and reduce exhaust emissions. Therefore, it is a strong candidate for transport and diesel powered machines including electricity generators and other off-road machines. In this research, a waste cooking oil derived HVO diesel was investigated for its combustion and emission performance including ignition delays, size segregated particulate number emissions and gaseous emissions. The results were compared to the standard petroleum diesel. A EURO5 emission compliant three litre, direct injection, intercooled IVECO diesel engine equipped with EGR was used which has a maximum power output of 96kW. The engine was equipped with an integrated DOC and DPF aftertreatment system. Both the upstream and downstream of the aftertreatment emissions were measured. The tests were conducted at different RPM and loads at steady state conditions.
Technical Paper

A Comparison of Tailpipe Gaseous Emissions for RDE and WLTC Using SI Passenger Cars

2017-10-08
2017-01-2391
The drive characteristics and gaseous emissions of legislated Real Driving Emissions (RDE) test data from 8 different spark ignition vehicles were compared to data from corresponding Worldwide harmonized Light vehicles Test Cycle (WLTC) tests. The effect of the official RDE exclusion of cold start and idling on the RDE test, and the effect of the use of the moving averaging window (MAW) analysis technique, were simultaneously investigated. Specific attention was paid to differences in drive characteristics of the three different driving modes and the effect this had on the distance-based CO2, CO and NOx emission factors for each. The average velocity of the RDE tests was marginally greater than the WLTC tests, while the average acceleration was smaller. The CO2 emission appeared on average 4% lower under the RDE tests compared to the WLTC tests, while the CO was 60% lower. The NOx values were 34% lower under the RDE testing, and appeared to be linked to the average acceleration.
Technical Paper

Real World Driving: Emissions in Highly Congested Traffic

2017-10-08
2017-01-2388
The emissions from vehicles in real world driving are of current concern, as they are often higher than on legislated test cycles and this may explain why air quality in cities has not improved in proportion to the reduction in automotive emissions. This has led to the Real Driving Emissions (RDE) legislation in Europe. RDE involves journeys of about 90km with roughly equal proportion of urban, rural and motorway driving. However, air quality exceedances occur in cities with urban congested traffic driving as the main source of the emissions that deteriorate the air quality. Thus, the emissions measured on RDE journeys may not be relevant to air quality in cities. A Temet FTIR and Horiba exhaust flow measurement system was used for the mass emissions measurements in a Euro 4 SI vehicle. A 5km urban journey on a very congested road was undertaken 29 times at various times so that different traffic congestion was encountered.
Technical Paper

Estimating Ozone Potential of Pipe-out Emissions from Euro-3 to Euro-5 Passenger Cars Fueled with Gasoline, Alcohol-Gasoline, Methanol and Compressed Natural Gas

2016-04-05
2016-01-1009
Along with the booming expansion of private car preservation, many Chinese cities are now struggling with hazy weather and ground-level ozone contamination. Although central government has stepped up efforts to purify skies above China, counter-strategies to curb ground-level ozone is comparatively weak. By using maximum incremental reactivity (MIR) method, this paper estimated the ozone forming potential for twenty-five Euro-3 to Euro-5 passenger cars burning conventional gasoline, methanol-gasoline, ethanol-gasoline, neat methanol and compressed natural gas (CNG). The results showed that, for all the fuel tested, VOC/NOx ratios and SR values decreased with the upgrading of emission standard. Except for Euro-3 M100 and Euro-4 M85, SR values for alternative fuel were to different degrees smaller than those for gasoline. When the emission standard was shifted from Euro-4 to Euro-5, OFP values estimated for gasoline vehicle decreased.
Technical Paper

Cold Start SI Passenger Car Emissions from Real World Urban Congested Traffic

2015-04-14
2015-01-1064
The tailpipe exhaust emissions were measured under real world urban driving conditions by using a EURO4 emissions compliant SI car equipped with an on-board heated FTIR for speciated gaseous emission measurements, a differential GPS for travel profiles, thermocouples for temperatures, and a MAX fuel meter for transient fuel consumption. Emissions species were measured at 0.5 Hz. The tests were designed to enable cold start to occur into congested traffic, typical of the situation of people living alongside congested roads into a large city. The cold start was monitored through temperature measurements of the TWC front and rear face temperatures and lubricating oil temperatures. The emissions are presented to the end of the cold start, defined when the downstream TWC face temperature is hotter than the front face which occurred at ∼350-400oC. Journeys at various times of the day were conducted to investigate traffic flow impacts on the cold start.
Technical Paper

Regulated, Carbonyl Emissions and Particulate Matter from a Dual-Fuel Passenger Car Burning Neat Methanol and Gasoline

2015-04-14
2015-01-1082
As a probable solution to both energy and environmental crisis, methanol and methanol gasoline have been used as gasoline surrogates in several provinces of China. Most recently, the Ministry of Environmental Protection of China is drafting a special emission standard for methanol-fueled light-duty vehicles. Given the scarcity of available data, this paper evaluated regulated emissions, carbonyl compounds and particulate matter from a China-5 certificated gasoline/methanol dual-fuel vehicle over New European Driving Cycle (NEDC). The results elucidated that in context with gasoline mode, CO emitted in methanol mode decreased 11.2%, while no evident changes of THC and NOx emissions were noticed with different fueling regimes. The total carbonyls and formaldehyde have increased by 39.5% and 19.8% respectively after switching from gasoline to methanol. A remarkable decrease of 65.6% in particulate matter was observed in methanol mode.
Technical Paper

Emissions from a HGV Using Used Cooking Oil as a Fuel under Real World Driving Conditions

2015-04-14
2015-01-0905
To maximize CO2 reduction, refined straight used cooking oils were used as a fuel in Heavy Goods Vehicles (HGVs) in this research. The fuel is called C2G Ultra Biofuel (C2G: Convert to Green Ltd) and is a fully renewable fuel made as a diesel replacement from processed used cooking oil, used directly in diesel engines specifically modified for this purpose. This is part of a large demonstration project involving ten 44-tonne trucks using C2G Ultra Biofuel as a fuel to partially replace standard diesel fuels. A dual fuel tank containing both diesel and C2G Ultra Biofuel and an on-board fuel blending system-Bioltec system was installed on each vehicle, which is able to heat the C2G Ultra Biofuel and automatically determine the required blending ratio of diesel and C2G Ultra Biofuel according to fuel temperature and engine load. The engine was started with diesel and then switched to C2G Ultra Biofuel under appropriate conditions.
Technical Paper

Numerical Simulation and Experimental Research on PPC Combustion and Emissions Characteristics of Diesel Engine

2015-04-14
2015-01-0401
The partially premixed combustion (PPC) was realized in a 6-cylinder heavy turbocharged diesel engine with single injection and EGR strategies. Combined with chemical reaction mechanism, the combustion and emission processes of this mode was analyzed using level-set turbulent flame propagation model. Based on the experiments and simulations, the impacts of PPC on the heat release, NOx and PM emissions were further investigated. The results show that both the early-injection and late-injection strategies have a two-stage heat release and significantly higher premixed combustion proportion than the conventional combustion mode, however, mixing controlled combustion was also observed in the late-injection mode. The NOx and PM emission was reduced simultaneously in PPC. However, in the late-injection strategy, this was achieved at the expense of increased HC emission. The dynamic process of the core components in PPC was much different from those in conventional diesel spray combustion.
Technical Paper

Fuel Consumption and GHG Reductions by using Used Cooking Oil as a Fuel in a HGV under Real World Driving Conditions

2014-10-13
2014-01-2727
Direct use of straight vegetable oil based biofuels in diesel engines without trans-esterification can deliver more carbon reductions compared to its counterpart biodiesel. However, the use of high blends of straight vegetable oils especially used cooking oil based fuels in diesel engines needs to ensure compatible fuel economy with PD (Petroleum Diesel) and satisfactory operational performance. There are two ways to use high blends of SVO (Straight Vegetable Oil) in diesel engines: fixed blending ratio feeding to the engine and variable blending ratio feeding to the engine. This paper employed the latter using an on-board blending system-Bioltec system, which is capable of heating the vegetable oils and feeding the engine with neat PD or different blends of vegetable oils depending on engine load and temperature.
Journal Article

Speciation of Nitrogen Compounds in the Tailpipe Emissions from a SI Car under Real World Driving Conditions

2014-10-13
2014-01-2812
The tailpipe exhaust emissions were measured using a EURO4 emissions compliant SI car equipped with on-board measurement systems such as a FTIR system for gaseous emission, a differential GPS for velocity, altitude and position, thermal couples for temperatures, and a MAX fuel meter for transient fuel consumption. Various nitrogen species emissions (NO, NO2, NOx, NH3, HCN and N2O) were measured at 0.5 Hz. The tests were designed and employed using two real world driving cycles/routes representing a typical urban road network located in a densely populated area and main crowded road. Journeys at various times of the day were conducted to investigate traffic conditions impacts such as traffic and pedestrian lights, road congestion, grade and turning on emissions, engine thermal efficiency and fuel consumption. The time aligned vehicle moving parameters with Nitrogen pollutant emission data and fuel consumption enabled the micro-analysis of correlations between these parameters.
Technical Paper

Comparison of Regulated Emissions and Particulate Matter of Gasoline/CNG Dual-Fuel Taxi Over New European Driving Cycle

2014-04-01
2014-01-1467
Compressed natural gas (CNG) is widely used as an alternative option in spark ignition engines because of its better fuel economy and in part cleaner emissions. To cope with the haze weather in Beijing, about 2000 gasoline/CNG dual-fuel taxis are servicing on-road. According to the government's plan, the volume of alternative fuel and pure electric vehicle will be further increased in the future. Thus, it is necessary to conduct an evaluation on the effectiveness of alternative fuel on curbing vehicular emissions. This research examined the regulated emissions and particulate matter of gasoline/CNG dual-fuel taxi over New European Driving Cycle (NEDC). Emission tests in gasoline- and CNG-fuelled, cold- and warm-start modes were done for all five taxies. Test vehicles, Hyundai Elantra, are powered by 1.6L spark-ignited engines incorporated with 5-gear manual gearboxes.
Journal Article

Determination of Carbon Footprint using LCA Method for Straight Used Cooking Oil as a Fuel in HGVs

2014-04-01
2014-01-1948
In order to improve energy supply diversity and reduce carbon dioxide emissions, sustainable bio-fuels are strongly supported by EU and other governments in the world. While the feedstock of biofuels has caused a debate on the issue of sustainability, the used cooking oil (UCO) has become a preferred feedstock for biodiesel manufacturers. However, intensive energy consumption in the trans-esterification process during the UCO biodiesel production has significantly compromised the carbon reduction potentials and increased the cost of the UCO biodiesel. Moreover, the yield of biodiesel is only ∼90% and the remaining ∼10% feedstock is wasted as by-product glycerol. Direct use of UCO in diesel engines is a way to maximize its carbon saving potentials.
Journal Article

Determination of GHG Emissions, Fuel Consumption and Thermal Efficiency for Real World Urban Driving using a SI Probe Car

2014-04-01
2014-01-1615
A SI probe car, defined here as a normal commercial car equipped with GPS, in-vehicle FTIR tailpipe emission measurement and real time fuel consumption measurement systems, and temperature measurements, was used for measuring greenhouse gas emissions including CO2, N2O and CH4 under real world urban driving conditions. The vehicle used was a EURO4 emission compliant SI car. Two real world driving cycles/routes were designed and employed for the tests, which were located in a densely populated area and a busy major road representing a typical urban road network. Eight trips were conducted at morning rush hours, day time non-peak traffic periods and evening off peak time respectively. The aim is to investigate the impacts of traffic conditions such as road congestion, grade and turnings on fuel consumption, engine thermal efficiency and emissions.
Technical Paper

Diesel Cold Start into Congested Real World Traffic: Comparison of Diesel, B50, B100 for Gaseous Emissions

2013-10-14
2013-01-2528
A cold start Euro 3 1.8 litre Diesel vehicle with an oxidation catalyst was used to investigate real world exhaust emissions over a driving cycle that included urban cold start congested traffic driving conditions. The aim was to identity those aspects of cold start real world driving responsible for higher emissions than in test cycles. Higher real world emissions may contribute to the problem of air quality in urban areas, which has not improved in quality in proportion to the reduced in vehicle exhaust emissions. Diesel, B50 and B100 fuel were compared to determine if real world driving effects were worse for B50 and B100 fuels due to their lower volatility and higher viscosity. The biofuel was WRME, derived from waste rape seed cooking oil. A multifunctional additive package was added to the biofuel at 800ppm to control fuel injector deposit formation. Gaseous emissions were monitored using an on-board heated Temet FTIR exhaust emission analyzer.
Technical Paper

Real World Diesel Engine Greenhouse Gas Emissions for Diesel Fuel and B100

2013-04-08
2013-01-1514
The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport using a probe vehicle: CO₂, N₂O and CH₄ emissions as a function temperature. It should be highlighted that methane is a greenhouse gas that similarly to carbon dioxide contributes to global warming and climate change. An oxidation catalyst was used to investigate CO₂, N₂O and CH₄ GHG emissions over a real-world driving cycle that included urban congested traffic and extra-urban driving conditions. The results were determined under hot start conditions, but in congested traffic the catalyst cooled below its light-off temperature and this resulted in considerable N₂O emissions as the oxidation catalyst temperature was in the N₂O formation band. This showed higher N₂O during hot start than for diesel fuel and B100 were compared. The B100 fuel was Fatty Acid Methyl Ester (FAME), derived from waste cooking oil, which was mainly RME.
Technical Paper

Examining the Influence of Road Grade on Vehicle Specific Power (VSP) and Carbon Dioxide (CO2) Emission over a Real-World Driving Cycle

2013-04-08
2013-01-1518
The Carbon Dioxide (CO₂) emission from a EURO 3 diesel van over a real-world driving cycle were investigated utilizing part of the Leeds University - Headingly Ring Road (LU-HR) driving cycle, which comprises both an urban (congested) and extra-urban (high speed) driving section. The vehicle used in this research was a 1.8-liter Ford Connect TDCi diesel van. Emissions were monitored by a Portable Emissions Measurement System (PEMS) incorporating an on-board FTIR (Fourier Transform Infrared) exhaust emission measurement system, a Horiba On Board emissions measuring System (OBS 1300) which measured the exhaust flow rate and air/fuel ratio, and a RaceLogic VBOX II differential GPS system provided geographical position, speed and acceleration data. Route topography is known to have substantial influence on vehicle emission.
Journal Article

Combustion and Emission Characteristics of a Heavy-Duty Diesel Engine at Idle at Various Altitudes

2013-04-08
2013-01-1516
This present paper described an experimental study on the combustion and emission characteristics of a diesel engine at idle at different altitudes. Five altitudes ranging from 550m to up to 4500m were investigated. Combustion parameters including in-cylinder pressure and temperature, heat release, fuel mass burning and so forth, together with emission factors including CO, HC, NOx and PM were tested and analyzed. The result of on-board measurement manifested that in-cylinder pressure descended consistently with the rising of altitude, while both the maximum in-cylinder temperature and exhaust temperature ascended with the altitude. It was found that ignition delay was lengthened at higher altitude, but the combustion duration became shorter. The crank angle towards 90% fuel burnt has hardly changed with the variation of altitude. As for heat release, the difference of slopes observed at different altitudes was quite slight.
Technical Paper

Diesel Cold Start into Congested Real World Traffic: Comparison of Diesel and B100 for Ozone Forming Potential

2013-04-08
2013-01-1145
EU environmental law requires 30 ozone precursor volatile organic compounds (VOCs) to be measured for urban air quality control. In this study, 28 ozone precursor VOCs were measured at a rate of 0.5 Hz by an in-vehicle FTIR emission measurement system along with other VOCs. The vehicle used was a Euro 3 emission compliant diesel van. The test vehicle was started from a cold ambient temperature soak and driven under real world urban driving conditions. Diesel and B100 (100% Biodiesel) were compared using the same repeat journeys. The VOC emissions and OFP (ozone formation potential) were investigated as a function of engine warm up and ambient temperatures during cold start. The exhaust temperatures were measured along with the exhaust emissions. The temperature and duration of light off of the catalyst for VOC were monitored and showed a cold start period to catalyst light off that was considerably longer than would occur on the NEDC (New European Driving Cycle).
Technical Paper

Experimental and Modeling Study of Biodiesel Surrogates Combustion in a CI Engine

2013-04-08
2013-01-1130
This work concerns the oxidation of biodiesel surrogates in a CI engine. An experimental study has been carried out in a single-cylinder common-rail CI engine with soybean biodiesel and two biodiesel surrogates containing neat methyl decanoate and methyl decanoate/n-heptane blends. Tests have been conducted with various intake oxygen concentrations ranging from 21% to approximately 9% at intake temperatures of 25°C and 50°C. The results showed that the ignition delay and smoke emissions of neat methyl decanoate were closer to that of soybean biodiesel as compared with methyl decanoate/n-heptane blends. A reduced chemical kinetic mechanism for the oxidation of methyl decanoate has been developed and applied to model internal combustion engines. A KIVA code, coupled with the Chemkin chemistry solver, was used as the computational platforms. The effects of various intake oxygen concentrations on the in-cylinder emissions of OH and soot were discussed.
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