Viewing 1 to 30 of 245
Technical Paper
Rishikesh Venugopal, Neerav Abani, Ryan MacKenzie
This paper presents analytical and measured results on the effects of injection pattern design on piston thermal management in an Opposed-Piston, Two-Stroke (OP2S) diesel engine. The OP2S architecture investigated in this work comprises two opposing pistons forming an asymmetric combustion chamber with two opposing injectors mounted on the cylinder wall. This unique configuration offers opportunities to tailor the injection pattern to control the combustion heat flux and resulting temperatures on the piston surfaces while optimizing combustion simultaneously. This study utilizes three-dimensional (3D) computational fluid dynamics (CFD) with state-of-the-art spray, turbulence and combustion models that include detailed chemistry to simulate the in-cylinder combustion and the associated flame/wall interactions. In addition, the measurements comprise a real-time thermocouple system, which allows for up to 14 locations to be monitored and recorded on the intake and exhaust pistons.
Technical Paper
E. G. Pariotis, D. T. Hountalas
This work is a part of an extended investigation conducted by the authors to validate and improve a newly developed quasi-dimensional combustion model. The model has been initially applied on an old technology, naturally aspirated HSDI Diesel engine and the results were satisfying as far as performance and pollutant emissions (Soot and NO) are concerned. But since obviously further and more extended validation is required, in the present study the model is applied on a new technology, heavy-duty turbocharged DI Diesel engine equipped with a high pressure PLN fuel injection system. The main feature of the model is that it describes the air-fuel mixing mechanism in a more fundamental way compared to existing multi-zone phenomenological combustion models, while being less time consuming and complicated compared to the more accurate CFD models. The finite volume method is used to solve the conservation equations of mass, energy and species concentration.
Technical Paper
Ashish Moholkar, Rizwan Khan, Jyotirmoy Barman, Sumit Arora
Increased options and flexibility in common rail direct injection provides a great opportunity for combustion optimization using fuel and air system with proper combustion chamber configuration. This paper elaborates the experimental work conducted for combustion optimization with combinations of piston bowl, intake port swirl, injector specifications and turbo charging on a 3.8 l four valve diesel engine of LDT application equipped with common rail fuel injection system and waste gate turbo charge. In meeting the target emission norms with internal engine measures, the design of the piston bowl and the nozzle configuration perform a defining role. Through simulations the best option had been carried out parametrically investigate the influence of piston bowl geometry and nozzle characteristics on the performance of the combustion system.
Technical Paper
Ossi Kaario, Anders Brink, Kalle Lehto, Karri Keskinen, Martti Larmi
New measurements have been done in order to obtain information concerning the effect of EGR and a paraffinic hydrotreated fuel for the smoke and NO emissions of a heavy-duty diesel engine. Measured smoke number and NO emissions are explained using detailed chemical kinetic calculations and CFD simulations. The local conditions in the research engine are analyzed by creating equivalence ratio - temperature (Phi-T) maps and analyzing the CFD results within these maps. The study uses different amount of EGR and two different diesel fuels; standard EN590 diesel fuel and a paraffinic hydrotreated vegetable oil (HVO). The detailed chemical kinetic calculations take into account the different EGR rates and the properties of the fuels. The residence time in the kinetical calculations is used to explain sooting combustion behavior within diesel combustion. It was observed that NO emission trends can be well captured with the Phi-T maps but the situation is more difficult with the engine smoke.
Technical Paper
Harri Hillamo, Teemu Anttinen, Ulf Aronsson, Clément Chartier, Oivind Andersson, Bengt Johansson
Combination of flow field measurements, shown in this paper, give new information on the effect of engine run parameters to formation of different flow fields inside piston bowl. The measurements were carried out with particle image velocimetry (PIV) technique in optical engine. Good set of results was achieved even though the feasibility of this technique in diesel engines is sometimes questioned. Main challenge in diesel engines is background radiation from soot particles which is strong enough to conceal the PIV signal. Window staining in diesel engine is also a problem, since very high particle image quality is needed for velocity analysis. All measurements were made in an optical heavy-duty diesel engine. Optical design of engine was Bowditch type [1]. The engine was charged and equipped with exhaust gas recirculation (EGR). The exhaust gas level was monitored by oxygen concentration and the level was matched to former soot concentration measurements.
Technical Paper
Armin Wehrfritz, Ossi Kaario, Ville Vuorinen, Aki Tilli, Martti Larmi
This paper aims to study numerically the influence of the number of fuel sprays in a single-cylinder diesel engine on mixing and combustion. The CFD simulations are carried out for a heavy-duty diesel engine with an 8 hole injector in the standard configuration. The fuel spray mass-flow rate was obtained from 1D-simulations and has been adjusted according to the number of nozzle holes to keep the total injected fuel mass constant. Two cases concerning the modified mass-flow rate are studied. In the first case the injection time was decreased whereas in the second case the nozzle hole diameter was decreased. In both cases the amount of nozzle holes (i.e. fuel sprays) was increased in several steps to 18 holes. Quantitative analyses were performed for the local air-fuel ratio, homogeneity of mixture distribution, heat release rate and the resulting in-cylinder pressure.
Technical Paper
Susumu Kohketsu, Keiki Tanabe, Koji Mori
Injection rate shape control is one feature of a diesel fuel injection system that is strongly desired at this time. However, in the conventional Common Rail System (CRS), it is difficult to control the injection rate because the injection pressure is constant during the injection period, resulting in a nearly rectangular rate shape. Thus, in order to achieve injection rate control in a CRS, a Next-generation Common Rail System (NCRS) was designed and the prototype system was fabricated. With two common rails, one for low pressure fuel, and the other for high pressure fuel, the NCRS achieves injection rate shape control by controlling the fuel injector supply pressure, from the two rails. The NCRS can achieve a clear “boot” shaped injection rate, and injection rig tests confirmed that the shape could be flexibly controlled via several control parameters.
Journal Article
C.A.J. Leermakers, B. Van den Berge, C.C.M. Luijten, L.P.H. de Goey, S. Jaasma
Increasing fuel prices keep bringing attention to alternative, cheaper fuels. Liquefied Petroleum Gas (LPG) has been well known for decades as an alternative fuel for spark ignition (SI) passenger cars. More recently, aftermarket LPG systems were also introduced to Heavy Duty transport vehicles. These (port fuel) systems either vaporize the liquid fuel and then mix it with intake air, or inject fuel into the engine's intake ports. While this concept offers significant fuel cost reductions, for aftermarket certification and large-scale OEM use some concerns are present. Unburned hydrocarbons (UHC) and carbon monoxide (CO) emissions are known to be high because of premixed charge getting trapped into crevices and possibly being blown through during valve-overlap. Apart from the higher emission levels, this also limits fuel efficiency and therefore cost savings.
Technical Paper
Derek Splitter, Reed Hanson, Sage Kokjohn, Martin Wissink, Rolf D. Reitz
Dual-fuel reactivity controlled compression ignition (RCCI) engine experiments were conducted with port fuel injection of isooctane and direct injection of n-heptane. The experiments were conducted at a nominal load of 4.75 bar IMEPg, with low isooctane equivalence ratios. Two sets of experiments explored the effects of direct injection timing with single and double injections, and multi-dimensional CFD modeling was used to explore mixture preparation and timing effects. The findings were that if fuel-liner impingement is to be avoided, double injections provide a 40% reduction in CO and HC emissions, resulting in a 1% increase in thermal efficiency. The second engine experiment showed that there is a linear relationship between reactivity (PRF number) and intake temperature. It was also found that if the premixed fuel fraction is above a certain limit, the high-temperature heat release (HTHR) can be manipulated by changing the global PRF number of the in-cylinder fuel blend.
Technical Paper
André Sperl
In the past few years the standards for pollutant emission on Diesel Engines in Brazil, especially regarding NOx and Particulate Material, have suffered drastic reductions. These reductions have been driven by international legislations and the fact that Proconve P6, equivalent to Euro IV, has been skipped in Brazil due to the unavailability of low sulfur fuel (50ppm and 10ppm), so now Proconve P7, equivalent to Euro V, would be implemented in 2012. The reductions imposed by Proconve P7(Euro V) as opposed to Proconve P5 (Euro III) the current emission legislation, determines a reduction of 60% on NOx and 80% on Particulate Matter (PM), imposing new challenges in emission control. Those emission levels can only be achieved through significant changes in the engine's hardware and the use of different after-treatment systems like the Particulate Filter (CDPF) and the Oxidation Catalyst (DOC), also using low sulfur fuel.
Technical Paper
Yan Tan, John Kiedaisch, Steve Gravante
Fuel injector performance is critical for fuel efficiency, combustion process, emissions, start ability, acceleration and combustion noise. The injector design is a complicated process. Simulation tools are playing an important role in virtual design, which could evaluate performance and optimize the design. This paper describes how analysis is used to identify and resolve the cause of low kidney pressure when oil pressure in rail is high in a diesel injector. 1D system performance analysis tool and 3D CFD analysis tool are utilized together to identify the potential causes of the problem. The test results are compared with the simulation results to determine the root cause. 1D and CFD tools are used again to setup the design target and optimize the design. The test shows that the optimum design provided by 1D analysis and 3D analysis effectively solves the low kidney pressure problem in the fuel injector.
Technical Paper
Raouf Mobasheri, Zhijun Peng
Effects of included spray angle with different injection strategies on combustion characteristics, performance and amount of pollutant emission have been computationally investigated in a common rail heavy-duty DI diesel engine. The CFD model was firstly validated with experimental data achieved from a Caterpillar 3401 diesel engine for a conventional part load condition at 1600 rev/min. Three different included spray angles (α = 145°, 105°, 90°) were studied in comparison with the traditional spray injection angle (α = 125°). The results show that spray targeting is very effective for controlling the in-cylinder mixture distributions especially when it accompanied with various injection strategies. It was found that 105° spray cone angle along with an optimized split pre- and post-Top Dead Center (TDC) injection strategy could significantly reduce NOx and soot emissions without much penalty of the fuel consumption, as compared to the wide spray angle.
Technical Paper
Prathan Srichai, Nuwong Chollacoop, Chinda Chareonphonphanich, Manida Tongroon, Preechar Karin
Abstract Nowadays, the diesel engine models are developed from a unit pump to a common-rail injector. With palm methyl ester (commonly known as biodiesel) with higher viscosity and density than conventional diesel being used as alternative fuel for diesel, palm methyl ester may affect the injection characteristics. Injection pressure is one of the important parameters of common rail injector. Because of its effects on the pressure between command port and control volume, which activates a needle lift during injection process. This paper presents injection characteristics of solenoid injector experimented in a Zeuch’s chamber with a focus on injection pressure frequency, injection pressure amplitude, injection pressure stable duration. Commercial diesel (with mandate of 5% biodiesel blend or B5) and palm methyl ester (B100) were used as the test fuels at various injection pressures (40, 80, 120 and 160 MPa).
Technical Paper
Mengqin Shen, Sara Lonn, Bengt Johansson
Partially premixed combustion (PPC) is a promising way to achieve high efficiency and low engine-out emissions simultaneously in a heavy-duty engine. Compared to Homogeneous Charge Compression Ignition (HCCI), it can be controlled by injection events and much lower HC and CO emissions can be achieved. This work focuses on the transition from HCCI to PPC and combustion and emissions characteristics during the process are investigated. Injection strategies, EGR and boost pressure were the main parameters used to present the corresponding effect during the transition.
Technical Paper
Sumito Yokobe, Tetsuya Oda, Katsuyuki Ohsawa, Takahiro Sumi, Shuhei Sugata, Keiichiro Yabuta
The spray characteristics and inside flow of a marine diesel injector were investigated both experimentally and numerically. From the experiments, we observed that the penetration of the sprays in the early injection stage gradually increases. This phenomenon differs significantly from that of the small automobile diesel injector, in which penetration increases linearly with time. Using the momentum method to obtain injection rate measurements, we observed an injection rate spike at each injection event just after the injection began. The observed spray results show that the small portion of fuel remaining inside the nozzle from the previous injection event is ejected first, and then the main volume of fuel is ejected. Both fuels accumulate as spray droplets and gradually accelerate after the early injection stage. Numerical simulations of the injector's inside flow show that the fuel injection rate becomes saturated in needle lifts larger than 0.3 mm.
Technical Paper
Hideaki Osada, Noboru Uchida, Yoshio Zama
Impingement of a spray flame on the periphery of the piston cavity strongly affects heat loss to the wall. The heat release rate history is also closely correlated with the indicated thermal efficiency. For further thermal efficiency improvement, it is thus necessary to understand such phenomena in state of the art diesel engines, by observation of the actual behavior of an impinging spray flame and measurement of the local temperature and flow velocity. A top-view optically accessible engine system, for which flame impingement to the cavity wall can be observed from the top (vertically), was equipped with a high speed digital camera for direct observation. Once the flame impinged on the wall, flame tip temperature decreased roughly 100K, compared to the temperature before impingement.
Technical Paper
Takahito Niwa, Takashi Eguchi, Koichi Yamada, Satoshi Bunne, Toshihiko Omori, Takafumi Kato
With the diesel emissions and fuel consumption regulations and laws being tightened up, Common Rail System (CRS), capable of accurate and high-pressure diesel fuel injection, has become very popular in the world, and this CRS market is expected to continue to grow in the future. As use of the CRS becomes widespread, CRS is supposed to be used in a wide variety of environment, e.g. bad fuel (for example, much dust [1] and/or water), which increases concerns of CRS reliability. In an attempt to cope with such bad fuel properties, CRS and Fuel collected from the market was investigated. And based on this result, a new test method was worked out to simulate fuel stresses in the market. This test method verified the improved design of CRS with enhanced fuel robustness. This paper describes the new test method and the fuel robustness-enhancing effect of CRS based on the test method.
Technical Paper
Beat von Rotz, Kai Herrmann, Konstantinos Boulouchos
Fuel spray propagation and its morphology are important aspects for the in-cylinder mixture preparation in Diesel engines. Since there is still a lack of suitable measurements with regard to large 2-stroke marine Diesel engines combustion systems, a comprehensive data set of spray characteristics has been investigated using a test facility reflecting the specific features of such combustion systems. The spray penetration, area and cone angle were analysed for a variation of gas density (including the behaviour at evaporation and non-evaporating conditions), injection pressure and nozzle diameter. Moreover, spray and swirl flow interaction as well as fuel quality influences have been studied. To analyse the impacts and effects of each measured parameter, an empirical correlation for the spray penetration has been derived and discussed for all measurements presented.
Journal Article
Gordon McTaggart-Cowan, Ken Mann, Jian Huang, Ashish Singh, Bronson Patychuk, Zheng Xiong Zheng, Sandeep Munshi
Abstract Retaining the diesel combustion process but burning primarily natural gas offers diesel-like efficiencies from a natural-gas fuelled heavy-duty engine. This combustion event is limited by the injection pressure of the fuel, as this dictates the rate of mixing and hence of combustion. Typical late-cycle direct injection applications are limited to approximately 300 bar fuel pressure. The current work reports on tests for the first time at natural gas injection pressures up to 600 bar. The results show that significant efficiency and particulate matter reductions can be achieved at high loads, especially at higher speeds where the combustion is injection rate limited at conventional pressures. Increases in combustion noise and harshness are a drawback of higher pressures, but these can be mitigated by reducing the diameter of the nozzle gas holes to control the fuel injection rate.
Technical Paper
Sauhard Singh, Reji Mathai, A. K. Sehgal, R. Suresh, B. P. Das, Nishant Tyagi, Jaywant Mohite, N. B. Chougule
Abstract Depletion of fossil fuel reserves, the unsteadiness of their prices and the increasingly stricter exhaust emission legislation put forward attention of world towards use of alternate fuels. The ever increasing demand for ecologically friendly vehicles can be met by use of clean fuels like Compressed Natural Gas (CNG) and Hydrogen (H2). Lower carbon to hydrogen ratio of CNG makes it a cleaner fuel, due to this CNG is gaining popularity as an internal combustion (IC) engine fuel in transport sector. Hydrogen fuel for IC engines is also being considered as a future fuel due to its simple carbon less structure. However, several obstacles have to be overcome before widespread utilization of hydrogen as an IC engine fuel can occur in the transport sector. The 18 percent hydrogen enriched CNG fuel referred to as HCNG has the potential to lower emissions and could be considered a first step towards promotion of a Hydrogen economy.
Technical Paper
Umashankar Mohan Chandra Joshi, Manan Jyotin Trivedi, Ziliang Zheng, Peter Schihl, Naeim A. Henein
All previous correlations of the ignition delay (ID) period in diesel combustion show a positive activation energy, which means that shorter ID periods are achieved at higher charge temperatures. This is not the case in the autoignition of most homogeneous hydrocarbons-air mixtures where they experience the NTC (Negative Temperature Coefficient ) regime in the intermediate temperature range, from about 800 K to 1000 K). Here, the autoignition reactions slow down and longer ID periods are experienced at higher temperatures. Accordingly the global activation energy for the autoignition reactions of homogeneous mixtures should vary from positive to negative values.
Technical Paper
Dhruv Gupta, Vasu Kumar, Soumya Roy, Naveen Kumar
Abstract The danger posed by climate change and the striving for securities of energy supply are issues high on the political agenda these days. Governments are putting strategic plans in motion to decrease primary energy use, take carbon out of fuels and facilitate modal shifts. Man's energy requirements are touching astronomical heights. The natural resources of the Earth can no longer cope with it as their rate of consumption far outruns their rate of regeneration. The automotive sector is without a doubt a chief contributor to this mayhem as fossil fuel resources are fast depleting. The harmful emissions from vehicles using these fuels are destroying our forests and contaminating our water bodies and even the air that we breathe. The need of the hour is to look not only for new alternative energy resources but also clean energy resources. Hydrogen is expected to be one of the most important fuels in the near future to meet the stringent emission norms.
Technical Paper
Wendy H. Kurniawan, Shahrir Abdullah, Zulkifli M. Nopiah, Kamaruzzaman Sopian
This paper describes the application and capability of neural network as an artificial intelligence tool to determine the performance and emissions in a compressed natural gas direct injection (CNG-DI) engine. A feed-forward back-propagation artificial neural network (BPANN) approach is explored to predict the combustion performance in terms of indicated power and emissions in the appearance of CO and NO emissions level. A series of numerical computations by means of computational fluid dynamics (CFD) code were carried out based on the statistics-based design of experiment method. The data for combustion process under various engine operating parameters at the fixed speed at 1000 rpm were obtained to train the developed artificial neural network (ANN).
Technical Paper
Rolf Dreisbach, Gernot Graf, Gerhard Kreuzig, Helmut Theissl, Ulrich Pfahl
This paper describes development challenges for Heavy-Duty (HD) on-highway Diesel Direct Injection (DDI™) engines to meet the extremely advanced US-EPA 2010 (later named US 2010) emission limits while further increasing power density in combination with competitive engine efficiency. It discusses technologies and solutions for lowest engine-out emissions in combination with most competitive fuel consumption values and excellent dynamic behavior. To achieve these challenging targets, base engine hardware requirements are described. In detail the development of EGR systems, especially the challenges of running high EGR rates over the whole engine speed range also at high load, the dynamic EGR control for transient engine operation to achieve lowest NOx emissions at the smoke limit with excellent load response is discussed. Also the effect of the turbo-machinery on power density and transient engine behavior is shown.
Technical Paper
Keiichi Okude, Kazutoshi Mori, Shiroh Shiino, Kiyoharu Yamada, Yusuke Matsumoto
This study has experimentally clarified the effects the pilot injection fuel quantity and pilot injection timing have on the mode of combustion of the pilot spray and exhaust emissions. The result shows that one of the points to effectively reduce exhaust emissions by pilot injection is to reduce the emissions produced by the pilot combustion itself. For that purpose it is effective to advance the pilot injection timing and to increase of pilot quantity. In this case, dividing the pilot injection into multiple small-quantity shots is a solution to avoid cylinder wall wetting.
Technical Paper
Mark Pecqueur, Kristof Ceustermans, Pieter Huyskens, Dimitrios Savvidis
Green fuels or alternative fuels are growing fast now days and can be used in every passenger car but also in many commercial vehicles. In various countries all around Europe such as Italy, Netherlands and Belgium LPG is a reasonable alternative fuel for small and medium cars. This study evaluated the performance of a Suzuki Liane fitted with a multipoint in-line gas fuel injection system. During the tests various exhaust gasses (CO, CO2, NOx, O2 and HC) and temperatures were measured in different load condition on a chassis dynamometer. All tests were conducted in the engines laboratory at Karel de Grode Hogeschool (KDG) in Antwerp, Belgium. The car was tested on a chassis dynamometer similar to the one described in [1], [2], [3] and various loads were applied at different gear settings. All measurements were taken under full load and four different gears (2nd gear, 3rd gear, 4th gear and 5th gear) were selected in the gear box.
Technical Paper
Rosca Radu, Rakosi Edward, Manolache Gheorghe
The paper presents some results concerning the use of a Biodiesel type fuel in a direct injection (D.I) Diesel engine. The fuel was produced from waste vegetable oil, collected from the local McDonalds' branch. The engine was fueled with a blend containing 50% Biodiesel and 50% Diesel fuel (B50, Biodiesel blend). The tests were developed on a D-110 Diesel engine (S/D= 130/108 mm, ε = 17, three in line cylinders); the output power, torque, BSFC, combustion pressure, pressure rate and autoignition delay were measured and the heat release rate was calculated. We noticed a slight decrease of the power indices when the Biodiesel type fuel was used (output power and torque) and also of the peak combustion rate. The peak heat release rate decreased, while the autoignition delay has decreased by 2…4° CA.
Technical Paper
M Subramanian, M Muralidharan, P C Kanal, R K Malhotra
This paper covers the test work done on the comparative characterization of particulates using different blends of biofuels (like biodiesel and ethanol in diesel fuel) in light commercial vehicle under different operating conditions. The test vehicle selected was equipped with Direct Injection (DI) diesel engine with inline fuel injection pump. Under transient operating condition (Indian Driving Cycle), the results indicate that with increased percentage of biodiesel (upto 20%) in the blend, particulate concentration decreases. However, with 5% ethanol diesel blend, particulate concentration increases when compared with neat diesel as well as biodiesel blends while mass concentrations are lower with both the biofuels as compared to neat diesel. It is observed that the nanoparticles are higher with 5% ethanol diesel in IDC test mode.
Technical Paper
Shusuke Okada, Jiro Senda
For protecting human health and preserving the clean environment, current regulations stipulate acceptable levels of particulate emissions based on the mass collected on filters obtained by sampling in diluted exhaust. Such regulations will be imposed not only on-road engines but also off-road engines. From the point of view of human health [1], so-called nano-particle (d<50nm) is thought to be nuisance because it could reach deeper lung tissue. So, many researches have been done in this research field [2]. A series of experiments were conducted on an off-road general purpose direct Injection (DI) diesel engine using EEPS (Engine Exhaust Particle Sizer) to make real time particle size distribution measurements possible. The data presented covers whole operating conditions including the operating modes of off-road diesel engine emission test (C1mode). Additionally, PM emissions in transient (NRTC test cycle) engine operation were examined.
Technical Paper
E. J. Lom, K. H. LY
Abstract Three methods of introducing gas into the DDC 8V92TA engine were evaluated: post-pilot in-cylinder injection; early in-cylinder injection just after exhaust valve closure; and port injection through an air inlet port. Post-pilot injection consistently produced the best combustion and HC emissions. Early in-cylinder injection often resulted in severe end gas knock, but gave higher thermal efficiency than diesel in some conditions. HC emissions were considerably higher than for post-pilot injection. Port injection gave smoother combustion than early in-cylinder injection but higher HC emissions. Its full load thermal efficiency tell between, and part load efficiency below, the other methods.
Viewing 1 to 30 of 245


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