Refine Your Search

Topic

Author

Affiliation

Search Results

Technical Paper

Investigation on Premixed Charge Compression Ignition Combustion Control Using Multi Pulse Ultrahigh Pressure Injection

2019-04-02
2019-01-1155
Compression ignition (CI) engines provide higher thermal efficiency compared to other internal combustion engines although large amounts of NOx and soot are produced during combustion. NOx and soot emissions can be reduced by using Premixed Charge Compression Ignition (PCCI) combustion. However, the problems of PCCI combustion include limited operating range, unstable start of combustion and an increase in combustion noise. The multi-pulse ultrahigh pressure injection allows fuel to be injected near TDC, improving mixture formation and enhancing the possibility to extend the operating range of PCCI combustion. The objective of this paper is to control and extend the operating range of PCCI combustion using multi-pulse ultrahigh pressure injection. This has not been studied before. Combustion characteristics were investigated using apparent rate of heat release analysis, heat balance analysis, exhaust emission measurement and soot concentration measurement.
Technical Paper

Impact of TiO2 and V2O5 on Sintered Mullite Porous Microstructure and Soot Oxidation Kinetics Using SEM and TGA

2019-03-25
2019-01-1407
The exhaust emissions from diesel combustion are the sources of particulate matter emitted to the atmosphere, which are components of air pollution that implicated in human health such as lung cancer. At present the diesel particulate filter can remove PM from the exhaust gas before emitted to the atmosphere. This research is investigating morphology and structure of acicular mullite to develop the fabrication process filter in order to study particulate matters trapping and oxidation mechanisms. This paper used two main substances to study the structure of diesel particulate filter (DPFs); Aluminum oxide (Al2O3) and Silicon dioxide (SiO2). These are mainly in the conventional DPFs. The variable substances are Titanium dioxide (TiO2) and Vanadium oxide (V2O5), which added to investigate and produce the acicular mullite DPFs structure. The mullite samples were sintered at 1300 oC with holding time of 1 h.
Technical Paper

A Cycle-to-Cycle Variation Extraction Method for Flow Field Analysis in SI IC Engines Based on Turbulence Scales

2019-01-15
2019-01-0042
To adhere to stringent environmental regulations, SI (spark ignition) engines are required to achieve higher thermal efficiency. In recent years, EGR (exhaust gas recirculation) systems and lean-burn operation has been recognized as key technologies. Under such operating conditions, reducing CCV (cycle-to-cycle variation) in combustion is critical to the enhancement of overall engine performance. Flow-field CCV is one of the considerable factors affecting combustion in engines. Conventionally, in research on flow fields in SI engines, the ensemble average is used to separate the measured velocity field into a mean component and a fluctuation component, the latter of which contains a CCV component and a turbulent component. To extract the CCV of the flow field, previous studies employed spatial filter, temporal filter, and POD (proper orthogonal decomposition) methods.
Technical Paper

The Effect of Exhaust Gas Recirculation on Performance and Emission of Ethanol Fumigated Diesel Engine

2017-11-05
2017-32-0101
Primary energy source such as fossil fuel keep decreasing due to various kind of usage. According to less amount of the fossil fuel, human seeks for an alternative fuel source such as alcohol. Alcohol like ethanol can be produced easily from strarchy plant. But using alcohol as blended fuel with diesel fuel doesn't work well because alcohol has low cetane number, lack of lubricity and very low miscibility with diesel fuel. To overcome this, fumigation system or port fuel injection of alcohol seems interesting. Although it requires more complicate system but it can compensate the miscibility issue and alcohol can be used in higher dose to give more energy. Diesel engine produces a lot of emission such as NOx and some other carbon content emission like HC, CO and soot due to they run in lean condition as their characteristic. Modern diesel engines are now coupled with exhaust gas recirculation system to help reduce in main emission like NOx.
Technical Paper

Effect of Biofuel and Soot on Metal Wear Characteristic Using Electron Microscopy and 3D Image Processing

2017-11-05
2017-32-0095
The soot contamination in used engine oils of diesel engine vehicles was about 1% by weight. The soot and metal wear particle sizes might be in the range of 0-1 µm and 1-25 µm, respectively. The characteristics of soot affecting on metal wear was investigated. Soot particle contamination in diesel engine oil was simulated using carbon black. Micro-nanostructure of soot particles were studied by scanning electron microscopy (SEM), transmission electron microscopy (TEM) and laser diffraction spectroscopy (LDS). The metal wear behavior was studied by means of a Four-Ball tribology test with wear measured. Wear roughness in micro-scale was investigated by high resolution optical microscopy (OM) , 3D rendering optical technique and SEM image processing method. It was found that the ball wear scar diameter increased proportionally to the soot primary particle size. The effect of biodiesel contamination were also increasing in wear scar diameter.
Technical Paper

Impact of Biodiesel on Small CI Engine Combustion Behavior and Particle Emission Characteristic

2017-11-05
2017-32-0094
Diesel engines are high thermal efficiency because of high compression ratio but produce high concentration of particulate matter (PM) because of direct injection fuel diffusion combustion. PM must be removed from the exhaust gas to protect human health. This research describes biodiesel engine performance, efficiency and combustion behavior using combustion pressure analyzer. It was clearly observed that PM emitted from CI engines can be reduced by using renewable bio-oxygenated fuels. The morphology and nanostructure of fossil fuel and biofuel PMs were investigated by using a Scanning electron microscopy (SEM) and Transmission electron microscopy (TEM). The morphology of biodiesel and diesel doesn’t have much different in the viewpoint of particulate matter trapping using DPF micro surface pores. The agglomerated ultrafine particles and primary nanoparticles sizes of diesel and biodiesel engine’s PM are approximately 50-500 nm and 20-50 nm, respectively.
Technical Paper

Heat Transfer Analysis in a Diesel Engine Based on a Heat Flux Measurement Using a Rapid Compression and Expansion Machine

2017-11-05
2017-32-0115
To investigate the heat transfer phenomena inside the combustion chamber of a diesel engine, a correlation for the heat transfer coefficient in a combustion chamber of a diesel engine was investigated based on heat flux measured by the authors in the previous study(8) using the rapid compression and expansion machine. In the correlation defined in the present study, thermodynamically estimated two-zone temperatures in the burned zone and the unburned zone are applied. The characteristic velocity given in the correlation is related to the speed of spray flame impinging on the wall during the fuel injection period. After the fuel injection period, the velocity term of the Woschni’s equation is applied. It was shown that the proposed correlation well expresses heat transfer phenomena in diesel engines.
Journal Article

Scanning Electron Microscopic Visualization of Bridge Formation inside the Porous Channels of Diesel Particulate Filters

2016-10-24
2016-01-9079
Time-lapse images of particulate matter (PM) deposition on diesel particulate filters (DPFs) at the PM-particle scale were obtained via field-emission scanning electron microscopy (FE-SEM). This particle scale time-series visualization showed the detailed processes of PM accumulation inside the DPF. First, PM introduced into a micro-pore of the DPF wall was deposited onto the surface of SiC grains composing the DPF, where it formed dendritic structures. The dendrite structures were locally grown at the contracted flow area between the SiC grains by accumulation of PM, ultimately constructing a bridge and closing the porous channel. To investigate the dominant parameters governing bridge formation, the filtration efficiency by Brownian diffusion and by interception obtained using theoretical filtration efficiency analysis of a spherical collector model were compared with the visualization results.
Technical Paper

Driving Cycle Simulation of a Vehicle with Gasoline Homogeneous Charge Compression Ignition Engine Using a Low-RON Fuel

2016-10-17
2016-01-2297
An improvement of thermal efficiency of internal combustion engines is strongly required. Meanwhile, from the viewpoint of refinery, CO2 emissions and gasoline price decrease when lower octane gasoline can be used for vehicles. If lower octane gasoline is used for current vehicles, fuel consumption rate would increase due to abnormal combustion. However, if a Homogeneous Charge Compression Ignition (HCCI) engine were to be used, the effect of octane number on engine performance would be relatively small and it has been revealed that the thermal efficiency is almost unchanged. In this study, the engine performance estimation of HCCI combustion using lower octane gasoline as a vision of the future engine was achieved. To quantitatively investigate the fuel consumption performance of a gasoline HCCI engine using lower octane fuel, the estimation of fuel consumption under different driving test cycles with different transmissions is carried out using 1D engine simulation code.
Technical Paper

Characterization of Biodiesel Particle Emission in Trapping and Regeneration Processes on Cordierite Diesel Particulate Filter

2015-11-17
2015-32-0821
As well-known, the diesel engine has the highest thermal efficiency at the same load as compared with internal combustion engine but its disadvantage is particulate matter (PM) emitted to the atmosphere. The studies of this paper were divided into two parts. The first part studied the quantity of PM from the both diesel and biodiesel fuels at 80% load (2400 rpm) by the trapping process on diesel particulate filter (DPF) used in a partial flow dilution tunnel. The second part studied the regeneration process of PM under the flow rate of oxygen and nitrogen gas of 13.5 L/min with 10%, 15%, and 21% of oxygen gas. The result showed that amount of PM from biodiesel fuel was lower around two times than PM from diesel fuel. The duration in regeneration process of biodiesel's PM was shorter than diesel while increasing of oxygen percentage can reduce regeneration time.
Technical Paper

NOx Reduction with the HC-SCR System over Cu/Zeolite Based Catalysts

2015-09-01
2015-01-2012
Diesel engine is one the effective solutions for reducing CO2 and recognized as a leading candidate for mitigating global warming. To comply with increasingly stringent emission standards, all diesel engines require some sort of NOx control systems such as selective catalytic reduction (SCR) systems. The SCR catalyst for reducing NOx from diesel engines is classified into two groups, urea-SCR and HC-SCR catalyst, respectively. Although the urea-SCR catalyst is widely recognized as promising de-NOx technology in respect to the NOx conversion efficiency, it have some outstanding issues such as ammonia slip, urea injection, storage space, freezing and some infrastructures for supplying urea water solutions. In an attempt to overcome the inherent shortcoming of existing urea-SCR catalyst, hydrocarbons have been considered as alternative reducing agents for SCR process, instead of NH3.
Journal Article

Investigation of Soot Oxidation Carried out on Membrane Filters Composed of SiC Nanoparticles

2015-09-01
2015-01-2015
The diesel particulate membrane filter (DPMF) is a good solution to the problem of high pressure drop that exists across diesel particulate filters (DPFs) as a result of the soot trapping process. Moreover, DPMFs that have a membrane layer composed of SiC nanoparticles can reduce the oxidation temperature of soot and the apparent activation energy. The SiC nanoparticles have an oxide layer on their surface, with a thickness less than 10 nm. From the visualization of soot oxidation on the surface of SiC nanoparticles by an environmental transmission electron microscope (ETEM), soot oxidation is seen to occur at the interface between the soot and oxide layers. The soot oxidation temperature dependency of the contact area between soot and SiC nanoparticles was evaluated using a temperature programmed reactor (TPR). The contact area between soot and SiC nanoparticles was varied by changing the ratio of SiC nanoparticles and carbon black (CB), which was used as an alternative to soot.
Technical Paper

A 3D DNS Investigation on the Flame-Wall Interactions and Heat Loss in a Constant Volume Vessel

2015-09-01
2015-01-1910
A direct numerical simulation of turbulent premixed flames in a constant volume vessel is conducted to understand flame-wall interactions and heat loss characteristics under the pressure rising condition. The contribution of the burnt region to the total heat flux is more significant compared to the reaction region. The velocity profiles indicate inward and outward motions. The profile of the turbulent kinetic energy is damped by the wall, and no distinct turbulence production is observed. Since the turbulence is weakened in the burnt region, the effect of near wall turbulence to the total wall heat flux is considered to be limited.
Technical Paper

Investigation and Improvement of LSPI Phenomena and Study of Combustion Strategy in Highly Boosted SI Combustion in Low Speed Range

2015-04-14
2015-01-0756
LSPI is an important issue to enable and enhance the effect of downsizing in SI engines. Experimental work was carried out by using 4 cylinder turbocharged gasoline engine, attaching the extra supercharger to get a higher boost pressure. Many parameters of driving condition, engine specification and lubricants were studied and some of them were extracted as the major items which affect the possibility of LSPI. Coolant temperature and Calcium (Ca) additive to lubricant had strong effect on the frequency of LSPI. Combustion strategy of strong miller cycle and LPEGR were also studied and compared in very high BMEP condition. Finally IMEPg of 3MPa at 1500rpm was achieved by using a single cylinder test engine equipped with 2-stage mechanically supercharged intake system.
Technical Paper

Numerical Simulation to Understand the Cause and Sequence of LSPI Phenomena and Suggestion of CaO Mechanism in Highly Boosted SI Combustion in Low Speed Range

2015-04-14
2015-01-0755
The authors investigated the reasons of how a preignition occurs in a highly boosted gasoline engine. Based on the authors' experimental results, theoretical investigations on the processes of how a particle of oil or solid comes out into the cylinder and how a preignition occurs from the particle. As a result, many factors, such as the in-cylinder temperature, the pressure, the equivalence ratio and the component of additives in the lubricating oil were found to affect the processes. Especially, CaCO3 included in an oil as an additive may be changed to CaO by heating during the expansion and exhaust strokes. Thereafter, CaO will be converted into CaCO3 again by absorbing CO2 during the intake and compression strokes. As this change is an exothermic reaction, the temperature of CaCO3 particle increases over 1000K of the chemical equilibrium temperature determined by the CO2 partial pressure.
Journal Article

Visualization and Analysis of LSPI Mechanism Caused by Oil Droplet, Particle and Deposit in Highly Boosted SI Combustion in Low Speed Range

2015-04-14
2015-01-0761
In this study, in order to clarify the mechanism of preignition occurrence in highly boosted SI engine at low speed and high load operating conditions, directphotography of preignition events and light induced fluorescence imaging of lubricant oil droplets during preignition cycles were applied. An endoscope was attached to the cylinder head of the modified production engine. Preigntion events were captured using high-speed video camera through the endoscope. As a result, several types of preignition sources could be found. Preignition caused by glowing particles and deposit fragments could be observed by directphotography. Luminous flame was observed around the piston crevice area during the exhaust stroke of preignition cycles.
Technical Paper

Scanning Electron Microscopic Visualization of Transition from Surface Pore Filtration to Cake Filtration Inside Diesel Particulate Filter Walls

2015-04-14
2015-01-1018
Surface pores that are open to the inlet channel below the surface play a particularly important role in the filtration of particulate matter (i.e., soot) inside the walls of a diesel particulate filter (DPF); they are closely related to the pressure drop and filtration efficiency through the DPF as well as the performance of the regeneration process. In this study, a scanning electron microscope (SEM) was used to dynamically visualize the soot deposition process at the particle scale as “time-lapse” images corresponding to the different increases in the pressure drop at each time step. The soot was first trapped at the deepest areas of the surface pores because the porous channels in this area were constricted by silicon carbide grains; soot dendrite structures were observed to grow and finally cause obstructions here.
Technical Paper

Comparison Study on Fuel Properties of Biodiesel from Jatropha, Palm and Petroleum Based Diesel Fuel

2014-03-24
2014-01-2017
The increase of air pollution and global warming is a threat for human life. Besides, the price of petroleum is increasing rapidly and the resources are diminishing. This obliged scientists and engineers to look for alternative sources of energy, which are cleaner and more sustainable. Biodiesel, defined as mono-alkyls of esters from vegetable oils and animals fat, is a cleaner renewable fuel and has been considered as the best alternative for petroleum based diesel fuel hence it can be used in any compression ignition engines without any significant modification. The main advantages of using biodiesel are its renewability and better quality of exhaust gas emissions due to their higher content of oxygen. The produce less soot and hence the feed stuck is plant it will regenerate the CO2 by the photosynthesis which ensures the renewability and reduces global warming.
Journal Article

Evaluation of the Performance of a Boosted HCCI Gasoline Engine with Blowdown Supercharge System

2013-10-15
2013-32-9172
HCCI combustion can realize low NOx and particulate emissions and high thermal efficiency. Therefore, HCCI combustion has a possibility of many kinds of applications, such as an automotive powertrain, general-purpose engine, motorcycle engine and electric generator. However, the operational range using HCCI combustion in terms of speed and load is restricted because the onset of ignition and the heat release rate cannot be controlled directly. For the extension of the operational range using either an external supercharger or a turbocharger is promising. The objective of this research is to investigate the effect of the intake pressure on the HCCI high load limit and HCCI combustion characteristics with blowdown supercharging (BDSC) system. The intake pressure (Pin) and temperature (Tin) were varied as experimental parameters. The intake pressure was swept from 100 kPa (naturally aspirated) to 200 kPa using an external mechanical supercharger.
Technical Paper

Physical Characterization of Biodiesel Particle Emission by Electron Microscopy

2013-10-15
2013-32-9150
Nanostructures of diesel and biodiesel engine particulate matters (PMs) were investigated by using a Transmission Electron Microscopy (TEM). The average single particle sizes of biodiesel and diesel PMs are approximately 30-40 nm and 50-60 nm, respectively. Image processing process was used to estimate each carbon platelet length by using TEM image. The average carbon platelet length of biodiesel and diesel PMs are in the range of 0.1-7.0 nm. Moreover, carbon atoms per cubic volume of PMs are approximately 500-900. The result shows that engine load and fuel property are strongly impact on the size of single particle and carbon atom density of particle. This is one of interesting behaviors need to be investigated for better understanding. The results of this research would be used as basic information for design and develop removing process of PM emitted from engine combustion which using in diesel and biodiesel fuels.
X