Low Emission Diesel Engine Research Articles

Spray characteristics of elliptical orifice spray in diesel engine under air movement conditions

The development of high-quality mixture is a critical requirement for achieving high-efficiency and low-emission diesel engines, and fuel injection system performance improvement and in-cylinder airflow organization are crucial ways for achieving high-quality mixture. The elliptical nozzle is used as the research object in this research, and numerical simulation is utilized to investigate the effect of different airflow speeds and directions on the atomization characteristics of the elliptical nozzle jet, in order to provide a theoretical basis for the engineering application of the elliptical nozzle in diesel engines. The results show that under the same airflow conditions, the vertical penetration distance of the spray decreases while the horizontal penetration distance increases with the use of elliptical orifices, the surface wave perturbation on the windward side is more violent, and reduce spray field the Sauter Mean Diameter (SMD). The spray projected area grew by 13.5%, the spray SMD dropped by 14.8%, and the vertical penetration distance of the spray with elliptical orifices fell by 18% with an increase in airflow velocity from 0 to 20 m/s. When the airflow direction and the spray direction were at a 90° angle and the SMD was lower than that of the circular orifice by 12.9%. The angle between the airflow direction and the short axis of the elliptical orifice was 30°when the spray projection area was larger, the perturbation of the spray body was more intense, and the surface wave amplitude was larger.

Energy-saving Fresh Water Generator That Uses Exhaust Heat from Low Emission Diesel Engine

Energy-saving Fresh Water Generator That Uses Exhaust Heat from Low Emission Diesel Engine

Excess Air Ratio Management in a Diesel Engine with Exhaust Backpressure Compensation.

The paper investigates the operation of a wideband universal exhaust gas oxygen (UEGO) sensor in a diesel engine under elevated exhaust backpressure. Although UEGO sensors provide the excess air ratio feedback signal primarily in spark ignition engines, they are also used in diesel engines to facilitate low-emission combustion. The excess air signal is used as an input for the fuel mass observer, as well as to run the engine in the low-emission regime and enable smokeless acceleration. To ensure a short response time and individual cylinder control, the UEGO sensor can be installed upstream of a turbocharger; however, this means that the exhaust gas pressure affects the measured oxygen concentration. Therefore, this study determines the sensor’s sensitivity to the exhaust pressure under typical conditions for lean burn low-emission diesel engines. Identification experiments are carried out on a supercharged single-cylinder diesel engine with an exhaust system mimicking the operation of the turbocharger. The apparent excess air measured with the UEGO sensor is compared to that obtained in a detailed exhaust gas analysis. The comparison of reference and apparent signals shows that the pressure compensation correlations used in gasoline engines do not provide the correct values for diesel engine conditions. Therefore, based on the data analysis, a new empirical formula is proposed, for which the suitability for lean burn diesel engines is verified.

Grey-Taguchi and ANN based optimization of a better performing low-emission diesel engine fueled with biodiesel

ABSTRACT The current work applies L9 (33) Orthogonal Array (OA) of Taguchi design to obtain an optimum combination of nature of fuel, speed of engine, and load for DI- CI diesel engine that is alternatively fueled with waste cooking oil (WCO) based pure biodiesel (B100) & 20% blend of biodiesel with neat diesel (B20) with an objective to achieve maximum reduction in smoke and NOx emissions and to enhance the output parameters like engine’s heat release, cylinder pressure and brake power with the conceivable dwindling of brake specific fuel consumption of the engine at various load conditions. The optimal input parameters (nature of fuel as B100, speed as 2300 rpm and load as 100%) were specified by the grey relational analysis in such a way that the preferred output results are successfully accomplished. Furthermore, analysis of variance (ANOVA) technique showed that the nature of fuel is the major leading factor with 44.28% impact on the output parameters. The experimental and ANN simulated results at the predicted optimal combination ensured the significant improvements of output response factors, thus validating the use of Grey-Taguchi method in reducing emissions and improving combustion and performance simultaneously.

Analysis of spray injection in a light duty CR diesel engine supported by non-conventional measurements

Abstract The injection process is one of the relevant phenomena occurring in modern diesel engine considering also that the fuel properties have been continuously changing. The interaction mechanisms between fuel quality, engine technologies, and emissions need to be understood to find the most effective approach towards innovative combustion strategies and low-emission diesel engines. In this work, the injection process occurring in a direct injection (DI) Common Rail (CR) diesel engine has been investigated from the start of injection up to the start of luminous combustion using different techniques. 2D visible and infrared imaging has been applied in single cylinder optical engine for several injection strategies typical of passenger car engine (homologation cycle NEDC). The spray penetration and cone angle obtained by 2D imaging are compared with the results of a 1D consolidated model for transient spray developed by the Sandia National Laboratory. Some modifications to the model boundary conditions have been made in order to assess the effect of fuel–wall interaction. This provided qualitative information of the impinged fuel inside the piston bowl. Finally, a good correlation between the fuel mass impinging on the chamber wall and the particulate matter (PM) emissions measured at the engine exhaust was found. The results of this study could be helpful for the determination of the best injection strategies in a diesel engine in order to reduce PM emissions.

Optimization of structure and combustion system for a low-emission light-duty diesel engine

Optimization of structure and combustion system for a low-emission light-duty diesel engine

Microstructure, Morphology, and Nanomechanical Properties Near Fine Holes Produced by Electro-Discharge Machining

Fine holes in metal alloys are employed for many important technological purposes, including cooling and the precise atomization of liquids. For example, they play an important role in the metering and delivery of fuel to the combustion chambers in energy-efficient, low-emission diesel engines. Electro-discharge machining (EDM) is one process employed to produce such holes. Since the hole shape and bore morphology can affect fluid flow, and holes also represent structural discontinuities in the tips of the spray nozzles, it is important to understand the microstructures adjacent to these holes, the features of the hole walls, and the nanomechanical properties of the material that was in some manner altered by the EDM hole-making process. Several techniques were used to characterize the structure and properties of spray-holes in a commercial injector nozzle. These include scanning electron microscopy, cross sectioning and metallographic etching, bore surface roughness measurements by optical interferometry, scanning electron microscopy, and transmission electron microscopy of recast EDM layers extracted with the help of a focused ion beam.

Effects of carbonaceous nanoparticles from low-emission and older diesel engines on human skin cells

Diesel exhaust particles (DEP) are major constituents of ambient air pollution and are associated with respiratory and cardiovascular diseases as well skin cell alterations in vitro. The epidermal cells are among the first cell populations exposed to chemical pollutants, including DEP, and are an important source of pro-inflammatory mediators. We evaluated the effects of carbonaceous soot particles from current low-emission (Euro IV) diesel engines on the oxidative and inflammatory response of normal human skin cells and compared the results with those induced by carbonaceous soot particles from an older diesel engine (BS) operating under black smoke conditions. We observed that both soot nanoparticles were spontaneously internalised by keratinocytes and distributed mostly around the cell nucleus. Moreover, at the same mass concentration, Euro IV soot particles exhibited a much higher oxidative, pro-fibrotic and toxic potential on these cell types than soot particles from the older diesel engine. These results are in agreement with and confirm our previous findings on human macrophage cells and strengthen the assumption that, at the same mass concentration, soot particles produced under low emission conditions are more cytotoxic than particles from the older diesel engine. This effect could be assigned to the defective surface structure of Euro IV diesel soot, rendering it highly active. Our findings highlight that the reduction of soot emission in terms of mass does not automatically lead to a reduction of the dangerous effects and show that soot particles from different diesel engines possess different biological behaviour towards human cells.

Impact of emission control strategy on NO2 in urban areas of Korea

Abstract Long-term trend in nitrogen dioxide (NO 2 ) levels was analyzed from 16 urban roadside (U-RS) locations in 7 major cities along with 5 reference background areas in Korea over an 11-year period (1998–2008). These NO 2 data were examined after being grouped into periods I (1998–2000) and II (2001–2008) in light of the major emission control strategy such as the natural gas vehicle supply (NGVS) program initiated since June 2000. There were contrasting signals between Seoul (capital) and others. Although the long-term trends were dominantly toward decline from most stations (5 out of 7) in Seoul, an increasing trend was dominant in other cities (7 out of 9 stations). A line of evidence collected in this study indicated that NO 2 levels and the emission ratio of NO 2 to NO x (f(NO 2 )) in U-RS sites have gradually decreased over the years due to the combined effects of various control efforts (e.g., the implementation of NGVS and the use of low emission diesel engines).

Experimental study of pollutant emission reduction for near-stoichiometric diesel combustion in a three-way catalyst

An experimental study was performed to examine the possibility of simultaneous reductions of NO x, hydrocarbons (HC), CO, and soot emissions for near-stoichiometric diesel combustion using a three-way catalyst and a diesel particulate filter (DPF). The DPF was deactivated in order to ensure the non-regeneration state and was just used as a soot filter trap upstream of the three-way catalyst. The goal of the research was to investigate the efficiency of emission conversion for an automotive diesel engine with a general three-way catalyst normally used for gasoline-powered vehicles under near-stoichiometric combustion operation. A modified single-cylinder engine was used for the experiments that considered throttled diesel combustion at 65–90 kPa intake pressure to achieve near-stoichiometric conditions, and a common rail injection system with 90 MPa injection pressure was used for mixture preparation and to avoid spray wall impingement. The results showed that the three-way catalyst was able to reduce NO x and CO emissions by up to nearly 98 per cent, and the DPF trapped soot emissions up to 99.6 per cent for near-stoichiometric operation. However, the particular palladium/rhodium catalyst formulation used in the study was less effective for HC emissions, which were only reduced by up to 57 per cent. It is concluded that the use of the present proposed three-way catalyst/DPF aftertreatment system provides significant promise for future efficient, low emission diesel engines.

Cytotoxicity and Inflammatory Potential of Soot Particles of Low-Emission Diesel Engines

We evaluated, in vitro, the inflammatory and cytotoxic potential of soot particles from current low-emission (Euro IV) diesel engines toward human peripheral blood monocyte-derived macrophage cells. The result is surprising. At the same mass concentration, soot particles produced under low-emission conditions exhibit a much highertoxic and inflammatory potential than particles from an old diesel engine operating under black smoke conditions. This effect is assigned to the defective surface structure of Euro IV diesel soot, rendering it highly active. Our findings indicate that the reduction of soot emission in terms of mass does not automatically lead to a reduction of the toxic effects toward humans when the structure and functionality of the soot is changed, and thereby the biological accessibility and inflammatory potential of soot is increased.

Application of hybrid evolutionary algorithms to low exhaust emission diesel engine design

A hybrid evolutionary algorithm, consisting of a genetic algorithm (GA) and particle swarm optimization (PSO), is proposed. Generally, GAs maintain diverse solutions of good quality in multi-objective problems, while PSO shows fast convergence to the optimum solution. By coupling these algorithms, GA will compensate for the low diversity of PSO, while PSO will compensate for the high computational costs of GA. The hybrid algorithm was validated using standard test functions. The results showed that the hybrid algorithm has better performance than either a pure GA or pure PSO. The method was applied to an engineering design problem—the geometry of diesel engine combustion chamber reducing exhaust emissions such as NOx, soot and CO was optimized. The results demonstrated the usefulness of the present method to this engineering design problem. To identify the relation between exhaust emissions and combustion chamber geometry, data mining was performed with a self-organising map (SOM). The results indicate that the volume near the lower central part of the combustion chamber has a large effect on exhaust emissions and the optimum chamber geometry will vary depending on fuel injection angle.

Injection system for fully variable control of the shape

Although today’s debates focus on particulate filters and methods for NOx reduction, injection rate shaping remains a key technology for cost-effective and low-emission diesel engines. The injection system presented in this article from IAV gmbH and Hanover University has been developed for research and test purposes and consists of a pressure modulation unit and a research injector with direct piezoelectric control of the injector needle; it is used to analyse the potential of free injection profile shaping as a means of optimising combustion processes.

Energy Issues for Vehicles: R&D, Carbon Sequestration, Fuel Conversion

The article “Meeting Energy Challenges: Technology and Policy,” by Ernest Moniz and Melanie Kenderdine (Physics Today, Physics Today 0031-9228 55 4 2002 40 https://doi.org/10.1063/1.1480781. April 2002, page 40 ), correctly points out the problem of doing business as usual while waiting for fuel-cell vehicle technology to have an impact.As described in Joan Ogden’s “Hydrogen: The Fuel of the Future?” in the same issue ( Physics Today 0031-9228 55 11 2002 69 https://doi.org/10.1063/1.1535009. page 69 ), the centerpiece of the present US Department of Energy plan to improve vehicle technology apparently involves a fuel-cell–powered vehicle, the “Freedom Car.” That vehicle, which would use stored hydrogen as fuel, could ultimately reduce petroleum consumption, greenhouse gas generation, and air pollution. However, a practical, economical hydrogen source that does not generate carbon dioxide will be required to obtain those benefits. The development of such a hydrogen source is a major challenge, as are the needs for practical hydrogen distribution and storage and for fuel-cell technology. It is uncertain just when such a hydrogen-powered vehicle could have a significant effect on the total fuel consumption of the US vehicle fleet; at best, that time is several decades away.Another R&D path is likely to provide significant benefits far sooner: improving mainstream propulsion system technologies. That option would involve not only the diesel and hybrid vehicle technologies emphasized by the Partnership for a New Generation of Vehicles and previously supported by DOE, but also much more aggressive government support for the development of high-efficiency gasoline engines. Gasoline engines currently dominate the US light-duty vehicle fleet, and their improvement should be a matter of urgency. Substantial fuel-consumption improvements, whose fuel cost savings could largely and relatively quickly offset the increase in cost, would facilitate widespread implementation, leading to significant impacts on national petroleum consumption, greenhouse-gas emissions, and reduced air pollution.A number of new gasoline engine systems could provide significant increases in efficiency at relatively modest cost. Some of these systems may also reduce the already low emissions from gasoline-engine vehicles. Opportunities include direct fuel injection and other lean burn concepts such as hydrogen-enhanced combustion and boost, variable valve control, and variable compression ratio. Moreover, new diesel engine systems, such as boosted advanced diesels with effective exhaust trap and catalyst systems, could significantly reduce the emissions that have inhibited use of more efficient light-duty diesel vehicles. In addition, homogeneous charge compression ignition, a new low-emission, high-efficiency engine combustion concept, has potential in both diesel and gasoline engines.However, DOE’s R&D funding of these promising technologies is insufficient relative to longer-term options such as fuel cells and advanced batteries. Moreover, DOE’s funding for internal combustion engines primarily supports diesel-related research, and little funding is focused on gasoline engine opportunities. Although industry does invest in developing new and improved engine technologies once their production viability is evident, many promising opportunities need substantial additional research to demonstrate that viability. The realization of those opportunities depends on the ideas and efforts of the research community, which, in turn, needs DOE support.Increasing use of efficient low-emission diesel engines (some 30% more efficient than today’s gasoline engines), coupled with widespread use of advanced gasoline engines up to 25% more efficient than today’s engines, would significantly reduce US petroleum consumption. Our government’s investment in R&D on these mainstream engine technology improvements is insufficient. We are especially neglecting high-efficiency gasoline engines. Because petroleum provides both gasoline and diesel fuel in comparable quantities, we need better gasoline engines, too. Both an increase and different allocation of DOE’s resources seem in order.© 2002 American Institute of Physics.

超低エミッションディーゼル機関への挑戦(<特集>21世紀のエンジンシステム : 課題への挑戦)

超低エミッションディーゼル機関への挑戦(<特集>21世紀のエンジンシステム : 課題への挑戦)

Establishment of engine test method for evaluating detergency performance of automobile diesel engine oils

A joint program between JALOS (Japanese Lubricating Oil Society) and JASO (Japanese Automobile Standards Organization) has established a “next generation” piston detergency test method for diesel engine oils aimed at impending low emission diesel engine hardware in Japan. Three test methods were examined with three different engines. The results showed that each method could discriminate the performance level of the oils tested. Finally, the IDI (NA) engine of Nissan Diesel TD25 was chosen for the new JASO detergency test method. As well as having high-temperature and high-load test conditions it has the twin advantages of easy handling in operation and good availability of engine parts for the future.

Development of low emission diesel engine ? The effect of electronically controlled common-rail type fuel injection system on engine performance, exhaust emission, smoke Yusuke Adachi, Akira Matuura, Naoaki Uchino, Kiyoshi Suginuma (Hino Motors, Ltd.)

Development of low emission diesel engine ? The effect of electronically controlled common-rail type fuel injection system on engine performance, exhaust emission, smoke Yusuke Adachi, Akira Matuura, Naoaki Uchino, Kiyoshi Suginuma (Hino Motors, Ltd.)