Effects of continuously regenerating diesel particulate filters on regulated emissions and number-size distribution of particles emitted from a diesel engine

The effects of continuously regenerating diesel particulate filter （CRDPF） systems on regulated gaseous emissions, and number-size distribution and mass of particles emanated from a diesel engine have been investigated in this study. Two CRDPF units （CRDPF-1 and CRDPF-2） with different specifications were separately retrofitted to the engine running with European steady-state cycle （ESC）. An electrical low pressure impactor （ELPI） was used for particle number-size distribution measurement and mass estimation. The conversion/reduction rate （RcR） of hydrocarbons （HC） and carbon monoxide （CO） across CRDPF-1 was 83% and 96.3%, respectively. Similarly, the RCR of HC and CO and across CRDPF-2 was 91.8% and 99.1%, respectively. The number concentration of particles and their concentration peaks; nuclei mode, accumulation mode and total particles; and particle mass were highly reduced with the CRDPF units. The nuclei mode particles at downstream of CRDPF-1 and CRDPF-2 decreased by 99.9% to 100% and 97.8% to 99.8% respectively; and the particle mass reduced by 73% to 92.2% and 35.3% to 72.4%, respectively, depending on the engine conditions. In addition, nuclei mode particles increased with the increasing of engine speed due to the heterogeneous nucleation initiated by the higher exhaust temperature, while accumulation mode particles were higher at higher loads due to the decrease in the air-to-fuel ratio （A/F） at higher loads.

Regulated and Speciated Hydrocarbon Emissions from a Dual Fuel Light Duty Vehicle with and Without a Three-Way Catalyst

The regulated pollutants （CO,HC and NOx） and unregulated pollutants （volatile organic compounds and carbonyl compounds）,emitted from a dual fuel vehicle fueled with gasoline and E10 fuel,are measured under a transient cycle and steady modes.The impacts of a three-way catalyst （TWC） are investigated for the two types of fuels.The measured results show that NOx and acetaldehyde emitted from the E10-fueled car are much more than that from the gasoline-fueled car under the same modes.On the basis of maximum incremental reactivity （MIR） factors and emissions of organic gases,the ozone specific reactivity of the tailpipe gases are evaluated.

Durability of three-way and close-coupled catalysts for Euro IV regulation

The durability of three-way catalyst （TWC） and corresponding close-coupled catalyst （CCC） for Euro Ⅳ stage regulation was investigated through Vehicle Road Running Mode tests, whereas emissions of regulated pollutants of three car fleet were investigated at every 100,000 km miles. The results showed that HC, NOx, and CO emission values could meet Euro Ⅳ regulation limits at every point. The redox properties of TWC and CCC were measured by CO reduction during each isothermal. It was obvious that both aged TWC and aged CCC behaved a good redox property at 673 and 773 K. Based on XRD and BET measurement results, TWC and CCC washcoat were characterized with good thermal stability.

Investigation of performance and emission characteristics using ethanol-blended gasoline fuel as a flex-fuel in two-wheeler vehicle mounted on a chassis dynamometer

This study investigated the performance and emissions of flex fuels in a 110-cc BS6-compliant fuel-injected two-wheeler without ethanol adaptation adjustments.The tests were carried out under controlled conditions on a chassis dynamometer at 1000,2000 and 3000 r.p.m.using ethanol blends from 10%ethanol(E10)to 85%ethanol(E85).Parameters examined included brake power(BP)output,brake-specific fuel consumption(BSFC),peak in-cylinder pressure and exhaust temperature.Emissions,including carbon monoxide(CO),hydrocarbons(HC),nitrogen oxide(NOx)and unregulated emissions,were also assessed.As the percentages of the ethanol blend increased from E10 to E85,there was a noticeable improvement in power output.At 1000 r.p.m.,the BP ranged from 2.4 to 4.6 kW for different blends.The BSFC and the peak in-cylinder pressure followed a similar pattern,indicating enhanced performance and fuel efficiency with higher ethanol concentrations.Interestingly,using E85 at 1000 r.p.m.resulted in a significant 41.08%reduction in exhaust temperature compared with E10,although this difference decreased with higher blend percentages.Furthermore,replacing E10 with E85 at 1000 r.p.m.reduced CO and HC emissions by 9.17%and 38.34%,respectively.In contrast,NOx emissions increased at all r.p.m.levels with higher-ethanol blends,peaking at a 415 parts per million increase at 3000 r.p.m.However,unregulated emissions decreased significantly with increased r.p.m.and ethanol content.In summary,the use of flex-fuel blends in a two-wheeler resulted in a modest increase in BP output,improved fuel efficiency and lower CO and HC emissions.These findings are vital for optimizing ethanol blend utilization in two-wheeler engines under low-load conditions,considering both performance and environmental aspects.

Towards low emissions and high thermal efficiency of gasoline compression ignition engine under high loads by modulating the fuel reactivity and injection strategy

Gasoline compression ignition(GCI) is a practicable way to obtain low emissions and high thermal efficiency of gasoline-like fuels in internal combustion engines. In this paper, the research octane number(RON) and injection strategy were coordinated to optimize the GCI engine performance and emissions under high loads. The direct injection and port injection were used to achieve two injection strategies: direct injection(DI) and port injection plus direct injection(PIDI), and the primary reference fuels(PRF) with the RON of 60, 70, 80 and 90 were used. The results show that using lower RON fuels under high loads, DI mode can achieve higher efficiency, while PIDI mode can achieve lower combustion noise at an expense of slightly lower fuel economy. When the DI mode is converted to PIDI mode with a pre-injection ratio of 30%, using PRF70 under 12 bar and the exhaust gas recirculation(EGR) rate of 40%, the gross indicated thermal efficiency and the maximum pressure rise rate are reduced by 1% and by 2 bar/°CA, respectively, while the particle emissions also decrease significantly, thus achieving low emissions and high efficiency. However, under the same load and EGR rate, DI mode produces less regulated and unregulated emissions than PIDI mode. In addition, the effect of fuel RON was obvious, the lower RON fuels exhibit obvious three-stage heat release in PIDI mode, however, PRF90 with higher RON only exhibits two-stage heat release, and the peak value of the firststage heat release rate is also lower than those of other fuels.

An evaluation of the emission profile for two-wheelers at a traffic junction

Two-wheeler vehicles are an important mode of transportation in developing countries. However, the emissions from two-wheeler vehicles are significant. Urban two-wheeler vehicles with gasoline-fueled engines produce NOx and particulate matter emissions that affect urban air quality. During traffic light stops and programmed stops, for instance, pollutants are emitted and are dangerous to human health. In this experimental study, two-wheeler vehicles with different makes, technologies and engine capacities were tested for exhaust emissions including gravimetric and online measurements at different engine speeds and a no load condition at a simulated traffic junction. Gravimetric measurements were performed by collecting the particulate mass （at two engine speeds： 1500 and 2500 rpm） from a diluted engine-out exhaust on quartz filter paper. Next, these collected particulates were used to determine the presence of metals, as well as the benzene soluble organic fraction （BSOF）. The total particulate mass, BSOF and trace elements were slightly higher at a higher engine speed （2500 rpm）. Online measurements were performed by sampling the engine exhaust （at four engine speeds： 1500, 2000, 2500, and 3000rpm） and using online instruments to determine the particle number and size distribution, the particle-bound polyaromatic hydrocarbons （PAHs）, the gaseous emissions and the smoke opacity. Engines with higher cubic capacity emitted a higher concentration of nano-particles. The particle-bound PAH concentration increased as the engine speed increased, but this concentration was notably low for the highest engine speed tested （3000 rpm）. The regulated gaseous emissions increased as the engine speed increased for all vehicles.

The optimal strategies in the supply chain with stochastic demand sensitivity to carbon emission

With the increasing awareness of low-carbon environmental protection,consumers prefer to purchase low-carbon products.In this paper,a two-echelon low-carbon supply chain consisting of one manufacturer and one retailer in classic single-period model with emission-sensitive stochastic demand is investigated.Firstly,optimal results for the decentralized and centralized decisions in the basic model are presented respectively.It manifests the effect of double marginalization which shows not only a lower order quantity but also higher unit carbon emission.Then,we are going to discuss the introduction of a buyback and cost-sharing contract,and two main carbon emission regulations in the decentralized model.Finally,compared with the basic model,numerical examples are studied on the optimal solutions to the total profit for the supply chain,order quantity,and unit/total carbon emission as the demand sensitivity to carbon emission/green investment coefficient/demand variance varies respectively before reaching several significant conclusions.

New emission standards in alignment with European regulations

Four standards, GB14761 - 1999 "Limits and measurement methods for emission of pollutants from motor vehicles", GB 17691 - 1999 "Limits and measurement methods for exhaust pollutants from compression ignition (C. I.) en-gines and vehicles equipped with C. I. engines ", GB 3847-1999 "Limits and measurement