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Viewing 1 to 30 of 172385
2017-10-24
Journal Article
2017-01-9380
Jan-Hubert Wittmann, Lars Menger
Current regulatory developments aim for stricter emission limits, increased environmental protection and purification of air on a local and global scale. In order to find solutions for a cleaner combustion process, it is necessary to identify the critical components and parameters responsible for the formation of emissions. This work provides an evaluation process for particle formation during combustion of a modern direct injection engine, which can help to create new aftertreatment techniques, such as a gasoline particle filter (GPF) system, that are fit for purpose. With the advent of “real driving emission” (RDE) regulations, which include market fuels for the particulate number testing procedure, the chemical composition and overall quality of the fuel cannot be neglected in order to yield a comparable emission test within the EU and worldwide.
2017-10-24
Journal Article
2017-01-9378
Eric Kurtz, Christopher J. Polonowski
Abstract The design of modern diesel-powered vehicles involves optimization and balancing of trade-offs for fuel efficiency, emissions, and noise. To meet increasingly stringent emission regulations, diesel powertrains employ aftertreatment devices to control nitrogen oxides, hydrocarbons, carbon monoxide, and particulate matter emissions and use active exhaust warm-up strategies to ensure those devices are active as quickly as possible. A typical strategy for exhaust warm-up is to operate with retarded combustion phasing, limited by combustion stability and HC emissions. The amount of exhaust enthalpy available for catalyst light-off is limited by the extent to which combustion phasing can be retarded. Diesel cetane number (CN), a measure of fuel ignition quality, has an influence on combustion stability at retarded combustion phasing. Diesel fuel in the United States tends to have a lower CN (both minimum required and average in market) than other countries.
2017-10-24
Journal Article
2017-01-9377
Senthil Ramalingam, Silambarasan Rajendran
Abstract Biodiesel as an alternative diesel fuel prepared from vegetable oils or animal fats has attracted more and more attention because of its renewable and environmental friendly nature. Many recent studies shows that 20% proportion of biodiesel-diesel blend (B20) can substantially reduce the hydrocarbon (HC), carbon monoxide (CO) and smoke emissions. However, there is a slight increase in NOx emission for B20 than that of diesel and it was a barrier to market expansion. The addition of antioxidant additives was the most effective method to mitigate the NOx emission. Hence, in this paper experimental investigation has been carried out to mitigate the NOx emission in Annona biodiesel (A20) operated diesel by addition of antioxidant additives. The antioxidant additives such as p-phenylenediamine, A-tocopherol acetate and L-ascorbic acid were used in the present investigation. In recent years Annona biodiesel has been considered as potential novel renewable energy source in India.
2017-10-08
Technical Paper
2017-01-2219
Xihui Wang
Conventional heat transfer fluids used for cooling fluids in vehicle cooling water jacket have relatively poor heat transfer performance.One method for enhance heat transfer in cooling-jacket uses nanofluids. Nanofluids have heat transfer enhancement merits .In the present study, the numerical simulation on Fe3O4 nanofluid flow in cooling water jacket of Gasline direct injection engine wax performed using computational fluid dynamics ( CFD) software FLUENT. The heat transfer coefficient of nanofluids was calculated and verified by experiment. Fe3O4 nano-particles were used in mixture of water/ethylene glycol as a base fluid. The thermal performance of the nanofluid was studied, also the thermal performance of a cooling-jacket was studied with CFD software. The simulation was performed for different volumetric concentrations of(1%,2%,5%) nanofluids of different engine speeds.
2017-10-08
Technical Paper
2017-01-2379
Qian Feng, Shu Shen, Mengliang Li, Zhijun Li, Kongjian Qin, Diming Lou, Jiguang Wang, Xiyu Fang
Recent toxicological and epidemiologic studies have shown that diesel emissions have been a significant toxic air contaminant. Catalyzed DPF (CDPF) not only significantly reduce the PM mass emissions (>90%), but also further promote carrier self-regeneration and oxidize more harmful gaseous pollutants by the catalyst coated on the carrier. However, some ultrafine particles and potentially harmful gaseous pollutants, such as VOCs species, originally emitted in the vapor-phase at high plume temperature, may penetrate through the CDPF filter. Furthermore, the components and content of catalyst coated on the CDPF could influence the physicochemical properties and toxicity intensity of those escaping ultrafine particles and gaseous pollutants. In this work, (1) we investigated the influence of precious metal content as a variable parameter on the physicochemical properties and catalytic activities of the small CDPF samples.
2017-10-08
Technical Paper
2017-01-2420
Bertrand Kerres, Andreas Cronhjort, Mihai Mihaescu, Ola Stenlaas
On-engine surge detection could help in reducing the safety margin towards surge, thus allowing higher boosting pressures and ultimately low-end torque. In this paper, experimental data from a truck turbocharger compressor mounted on the engine is investigated. A short period of compressor surge is provoked through a sudden, large drop in engine load. The compressor housing is equipped with knock accelerometers. Different signal treatments are evaluated for their suitability with respect to on-engine surge detection: the signal root mean square, the power spectral density in the surge frequency band, the recently proposed Hurst exponent, and a closely related concept optimized to detect changes in the underlying scaling behavior of the signal. For validation purposes, a visual observation of the air filter vibrations are also used to diagnose surge.
2017-10-08
Technical Paper
2017-01-2216
Yumin Fu
This document presents the development of a methodology for detecting rough road using the frequency analysis of the instantaneous engine speed signal. Combustion diagnosis (misfire detection) is enforced by EOBD/OBD II requirements, and eliminating the rough road driving affect on the diagnosis is critical for getting a robust misfire detection performance, especially for crankshaft speed based misfire diagnosis method. Although some kind of sensor is often used to identify that vehicle is traveling on rough road, the sensor less rough road monitor method is still more attractive for OEM to reduce cost, and some approaches have been developed past for the aim. The new approach presented here is based on the frequency domain analysis of engine speed characteristic excited by rough road traveling, and thus the frequency energy distribution comparison with public road driving and misfire introduced operation condition.
2017-10-08
Technical Paper
2017-01-2235
Ting Liu, Fuyuan Zhang, Yuedong Chao, Zongjie Hu, Liguang Li
EGR is thought to be another technique to improve gasoline engine fuel economy and emissions. In order to investigate the impacts of recirculated exhaust gas temperature on gasoline engine combustion and emissions, experimental study was conducted on a turbocharged PFI gasoline engine. The engine was equipped with a high pressure water-cooled EGR system, in which different EGR temperature was realized by using different EGR coolant. One way is using the room temperature civil water named LT-EGR (Low temperature EGR), and another way is to use hot engine coolant named HT-EGR (High temperature EGR). Therefore, the recirculated exhaust gas temperature after EGR cooler of LT-EGR is generally lower than that of HT-EGR. The engine ran at 2000rpm and 3000rpm, and the BMEP varied from 0.2MPa to 1.0MPa. At each operating point, there were three conditions: without EGR, 10% LT-EGR, 10% HT-EGR.
2017-10-08
Technical Paper
2017-01-2273
Xiaokun Nie, Wanhua Su
A numerical simulation was performed to investigate the pilot ignited natural gas combustion process in a direct injection natural gas engine. Various mixture distribution characteristics were compared in terms of the evolution of mixture equivalent ratio distributions and mixture concentration stratifications around top dead center (TDC). Based on above, the pilot injections were specially designed to investigate ignition core formation and its effects on natural gas combustion process. The result shows that pilot ignition sites have great impacts on pilot fuel ignition process and natural gas combustion process. The pilot ignition site on the region with rich NG/Air mixture is disadvantageous to the pilot fuel ignition due to a lack of oxygen, which is not beneficial to ignition core formation.
2017-10-08
Technical Paper
2017-01-2372
Yoshimitsu Kobashi, Shun Oooka, Lin Jiang, Jun Goto, Hideyuki Ogawa, Gen Shibata
To monitor and evaluate the emission-related components/systems and to determine the presence of malfunction or deterioration that can affect emissions, on-board diagnostics (OBD) is required by current regulations. With respect to the diesel particulate filter (DPF), a pressure drop across the DPF is monitored by the OBD since the pressure drop is approximately linear in particulate matter (PM) load and useful for evaluation. However, it is known that a sudden decrease in the DPF pressure drop is taken place under cold start conditions and the OBD misses the diagnosis. Although this seems to be caused by the water condensed in the exhaust pipe, no detailed mechanism has been obtained so far. The present study established an experimental system that can reproduce a rapid increase of the exhaust gas flow under cold start conditions and to control the amount of water supplied into the DPF. The sudden decrease in the DPF pressure drop was taken place by the water in this system as well.
2017-10-08
Technical Paper
2017-01-2302
Tobias Knorsch, Dmitrii Mamaikin, Philippe Leick, Philipp Rogler, Jin Wang, Zhilong Li, Michael Wensing
The fuel spray behavior in the near nozzle region of a gasoline injector is challenging to predict due to existing pressure gradients and turbulences of the internal flow and in-nozzle cavitation. Therefore, statistical parameters for spray characterization through experiments must be considered. The characterization of spray velocity fields in the near-nozzle region is of particular importance as the velocity information is crucial in understanding the hydrodynamic processes which take place further downstream during fuel atomization and mixture formation. This knowledge is needed in order to optimize injector nozzles for future requirements. In this study, the results of three experimental approaches for determination of spray velocity in the near-nozzle region are presented. Two different injector nozzle types were measured through high-speed shadowgraph imaging, Laser Doppler Anemometry (LDA) and X-ray imaging.
2017-10-08
Technical Paper
2017-01-2197
Vignesh Pandian Muthuramalingam, Anders Karlsson
Owing to increased interest in blended fuels for automotive applications, a great deal of understanding is sought for the behavior of multicomponent fuel sprays. This sets a new requirement on spray model since the volatility of the fuel components in a blend can vary substantially. It calls for careful solution to implement the differential evaporation process concerning thermodynamic equilibrium while maintaining a robust solution. This work presents the Volvo Stochastic Blob and Bubble (VSB2) spray model for multicomponent fuels. A direct numerical method is used to calculate the evaporation of multicomponent fuel droplets. The multicomponent fuel model is implemented into OpenFoam CFD code and the case simulated is a constant volume combustion vessel. The CFD code is used to calculate liquid penetration length for surrogate diesel (n-dodecane)-gasoline (iso-octane) blend and the result is compared with experimental data.
2017-10-08
Technical Paper
2017-01-2270
Fushui Liu, Yue Kang, Han Wu, Chia-Fon Lee, Yikai Li
CNG-diesel dual fuel combustion mode has been regarded as a practical engine operation strategy because it not only can remain the high thermal efficiency of diesel engine but also can make full use of an alternative fuel—natural gas,which has excellent advantages in economic performance and environmental protection. However, it is suffering from misfire and high HC emissions problems under cold start and low load conditions due to the low combustion speed and high ignition energy of natural gas. As known, hydrogen is a clear energy which has extremely high flammability. Thus, a certain proportion of hydrogen can be added in the natural gas (named HCNG after blending) to improve combustion. In current work, the effect of hydrogen addition on the combustion and flame propagation characteristics of dual fuel engine was studied based on an optical engine by using high speed camera to capture the flame images and Ki-Box to collect the cylinder pressures.
2017-10-08
Technical Paper
2017-01-2241
Xin Yu, Vincent Costanzo, Elana Chapman, Richard Davis
In this work, an experimental method was developed to induce and rate preignition tendency in a single cylinder research SI engine. By observing and quantifying the statistical behavior of some key combustion parameter, a single valued ranking was defined. The sensitivity of this induced preignition ranking method was then explored by varying different engine operating conditions. Finally, different hydrocarbon fuels were found to have relatively large variations on the ranking.
2017-10-08
Technical Paper
2017-01-2198
Zhihong Li, Guoxiu Li, Lan Wang, Hongmeng Li, Jie Wang, Haizhou Guo, Shuangyi He
The electromagnetic valve driving mechanism is the significant equipment, which plays a vital role in the unit pump injection system; therefore, the performance of the electromagnetic valve directly influences the function of the control system. Based on the operation conditions of the unit pump injection system, a steady electromagnetic valve model was modified to study the influence factors of electromagnetic force and the best combination to get the maximum electromagnetic force. The validation model was verified by experiment. The effects of some crucial parameters upon the electromagnetic force were investigated in the present paper, (including working airspace, magnetic pole’s cross-sectional area, coil position, coil turn, the armature thickness). The result shows that the electromagnetic force of the solenoid valve enhanced with the increasing driving current and reduced with the decreasing of working condition.
Viewing 1 to 30 of 172385