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Viewing 241 to 270 of 43695
2017-03-28
Technical Paper
2017-01-0751
Praveen Kumar, Yu Zhang, Michael Traver, David Cleary
Abstract In this study a detailed 1-D engine system model coupled with 3-D computational fluid dynamics (CFD) analysis was used to investigate the air system design requirements for a heavy duty diesel engine operating with low reactivity gasoline-like fuel (RON70) under partially premixed combustion (PPC) conditions. The production engine used as the baseline has a geometric compression ratio (CR) of 17.3 and the air system hardware consists of a 1-stage variable geometry turbine (VGT) with a high pressure exhaust gas recirculation (HP-EGR) loop. The analysis was conducted at six engine operating points selected from the heavy-duty supplemental emissions test (SET) cycle, i.e., A75, A100, B25, B50, B75, and C100.
2017-03-28
Technical Paper
2017-01-0746
Pietro Matteo Pinazzi, Fabrice Foucher
Abstract Gasoline Compression Ignition (GCI) engines based on Gasoline Partially Premixed Combustion (GPPC) showed potential for high efficiency and reduced emissions of NOx and Soot. However, because of the high octane number of gasoline, misfire and unstable combustion dramatically limit low load operating conditions. In previous work, seeding the intake of the engine with ozone showed potential for increasing the fuel reactivity of gasoline. The objective of this work was to evaluate the potential of ozone to overcome the low load limitations of a GCI engine. Experiments were performed in a single-cylinder light-duty CI engine fueled with 95 RON gasoline. Engine speed was set to 1500 rpm and intake pressure was set to 1 bar in order to investigate typical low load operating conditions. In the first part of the work, the effect of ozone on gasoline autoignition was investigate while the start of the fuel injection varied between 60 CAD and 24 CAD before TDC.
2017-03-28
Technical Paper
2017-01-0749
Suya Gao, Mianzhi Wang, Chia-Fon Lee
Abstract A new approach of NOx reduction in the compression-ignition engine is introduced in this work. The previous research has shown that during the combustion stage, the high temperature ignition tends to occur early at the near-stoichiometric region where the combustion temperature is high and majority of NOx is formed; Therefore, it is desirable to burn the leaner region first and then the near-stoichiometric region, which inhibits the temperature rise of the near-stoichiometric region and consequently suppresses the formation of NOx. Such inverted ignition sequence requires mixture with inverted phi-sensitivity. Fuel selection is performed based on the criteria of strong ignition T-sensitivity, negligible negative temperature coefficient (NTC) behavior, and large heat of vaporization (HoV).
2017-03-28
Technical Paper
2017-01-0745
R. Vallinayagam, S. Vedharaj, Yanzhao An, Alaaeldin Dawood, Mohammad Izadi Najafabadi, Bart Somers, Bengt Johansson
Abstract This study demonstrates the combustion stratification from conventional compression ignition (CI) combustion to partially premixed combustion (PPC). Experiments are performed in an optical CI engine at a speed of 1200 rpm for diesel and naphtha (RON = 46). The motored pressure at TDC is maintained at 35 bar and fuelMEP is kept constant at 5.1 bar to account for the difference in fuel properties between naphtha and diesel. Single injection strategy is employed and the fuel is injected at a pressure of 800 bar. Photron FASTCAM SA4 that captures in-cylinder combustion at the rate of 10000 frames per second is employed. The captured high speed video is processed to study the combustion homogeneity based on an algorithm reported in previous studies. Starting from late fuel injection timings, combustion stratification is investigated by advancing the fuel injection timings. For late start of injection (SOI), a direct link between SOI and combustion phasing is noticed.
2017-03-28
Technical Paper
2017-01-0740
Yu Zhang, Yuanjiang Pei, Nayan Engineer, Kukwon Cho, David Cleary
Abstract The current study utilized 3-D computational fluid dynamics (CFD) combustion analysis to guide the development of a viable full load range combustion strategy in a light-duty gasoline compression ignition (GCI) engine. A higher reactivity gasoline that has a research octane number (RON) of 70 was used for the combustion strategy development. The engine has a geometric compression ratio of 14.5 with a piston bowl designed to accommodate different combustion strategies and injector spray patterns. Detailed combustion optimization was focused on 6 and 18 bar gross indicated mean effective pressure (IMEPg) at 1500 rpm through a Design of Experiments approach. Two different strategies were investigated: (a) a late triggering fuel injection with a wide spray angle (combustion strategy #1); and (b) an early triggering fuel injection with a narrow spray angle (combustion strategy #2).
2017-03-28
Technical Paper
2017-01-0741
Xinlei Liu, Laihui Tong, Hu Wang, Zunqing Zheng, Mingfa Yao
Abstract In this work the gasoline compression ignition (GCI) combustion characterized by both premixed gasoline port injection and gasoline direct injection in a single-cylinder diesel engine was investigated experimentally and computationally. In the experiment, the premixed ratio (PR), injection timing and exhaust gas recirculation (EGR) rate were varied with the pressure rise rate below 10 bar/crank angle. The experimental results showed that higher PR and earlier injection timing resulted in advanced combustion phasing and improved thermal efficiency, while the pressure rise rates and NOx emissions increased. Besides, a lowest ISFC of 176 g/kWh (corresponding to IMEP =7.24 bar) was obtained, and the soot emissions could be controlled below 0.6 FSN. Despite that NOx emission was effectively reduced with the increase of EGR, HC and CO emissions were high. However, it showed that GCI combustion of this work was sensitive to EGR, which may restrict its future practical application.
2017-03-28
Technical Paper
2017-01-0702
Raouf Mobasheri, Mahdi Seddiq
Abstract The simultaneous effects of pilot fuel quantity and pilot injection timing on engine performance and amount of pollutant emission have been computationally investigated in a High Speed Direct Injection (HSDI) diesel engine. In this study, a modified parameter called “Homogeneity Factor of in-cylinder charge (HF)” has been applied to analyze the air-fuel mixing and combustion processes. For this purpose, the simulated results has been firstly compared with the experimental data and a good agreement has been achieved for simulating the in-cylinder pressure and the amount of pollutant emissions. Then, nine different strategies based on two variables (the amount of fuel mass in pilot and main injection as well as the dwell between two injections) have been investigated.
2017-03-28
Technical Paper
2017-01-0698
Thomas Koerfer, Dean Tomazic, Werner Bick, Christoph Menne, Michael Franke
Abstract In view of changing climatic conditions all over the world, Green House Gas (GHG) saving related initiatives such as reducing the CO2 emissions from the mobility and transportation sectors have gained in importance. Therefore, with respect to the large U.S. market, the corresponding legal authorities have defined aggressive and challenging targets for the upcoming time frame. Due to several aspects and conditions, like hesitantly acting clients regarding electrically powered vehicles or low prices for fossil fuels, convincing and attractive products have to be developed to merge legal requirements with market constraints. This is especially valid for the market segment of Light-Duty vehicles, like SUV’S and Pick-Up trucks, which are in high demand.
2017-03-28
Technical Paper
2017-01-0701
Aaron M. Bertram, Song-Charng Kong
Abstract The objective of this work was to identify methods of reliably predicting optimum operating conditions in an experimental compression ignition engine using multiple injections. Abstract modeling offered an efficient way to predict large volumes data, when compared with simulation, although the initial cost of constructing such models can be large. This work aims to reduce that initial cost by adding knowledge about the favorable network structures and training rules which are discovered. The data were gathered from a high pressure common rail direct injection turbocharged compression ignition engine utilizing a high EGR configuration. The range of design parameters were relatively large; 100 MPa - 240 MPa for fuel pressure, up to 62% EGR using a modified, long-route, low pressure EGR system, while the pilot timing, main timing, and pilot ratio were free within the safe operating window for the engine.
2017-03-28
Technical Paper
2017-01-0694
Tae Joong Wang, Jong Yoon Lee, Seung Kwon Hwang, Ja Yun Cho, Jeong Keun Park, Woong Gun Lee, Tae Sub Kim, Sang Won Jeong, Tae Kuk Kim
Abstract Doosan Infracore Corporation has developed the combustion system of a brand-new DX12 heavy-duty diesel engine equipped for 38 ~ 50 tonnage excavators and 4.2 ~ 4.5 m3 bucket-size wheel loaders which are mainly targeted to emerging countries. A variety of advanced combustion technologies were incorporated in the design of the DX12 engine to meet Tier3 emission legislation even with a mechanically controlled fuel injection equipment while ensuring around 2 % improvement in fuel consumption as well as over 8 % increase in rated power than its Tier2 predecessor. Mechanical-type diesel engine has a couple of significant advantages especially in terms of cost and maintenance compared to electronic-type counterpart. In addition, mechanical fuel system is better able to tolerate a low fuel quality which is potentially possible in emerging countries.
2017-03-28
Technical Paper
2017-01-0693
Seungwoo Kang, Wonkyu Cho, Choongsik Bae, Youngho Kim
Abstract This paper investigated the influence of the injector nozzle geometry on fuel consumption and exhaust emission characteristics of a light-duty diesel engine with 250 MPa injection. The engine used for the experiment was the 0.4L single-cylinder compression ignition engine. The diesel fuel injection equipment was operated under 250MPa injection pressure. Three injectors with nozzle hole number of 8 to 10 were compared. As the nozzle number of the injector increased, the orifice diameter decreased 105 μm to 95 μm. The ignition delay was shorter with larger nozzle number and smaller orifice diameter. Without EGR, the particulate matter(PM) emission was lower with larger nozzle hole number. This result shows that the atomization of the fuel was improved with the smaller orifice diameter and the fuel spray area was kept same with larger nozzle number. However, the NOx-PM trade-offs of three injectors were similar at higher EGR rate and higher injection pressure.
2017-03-28
Technical Paper
2017-01-0696
Yu Zhang, Steven Sommers, Yuanjiang Pei, Praveen Kumar, Alexander Voice, Michael Traver, David Cleary
Abstract This research investigates the combustion characteristics and engine performance of a conventional non-ethanol gasoline with a research octane number of 91(RON 91) and a higher reactivity RON80 gasoline under mixing-controlled combustion. The work was conducted in a model year 2013 Cummins ISX15 heavy-duty diesel engine. A split fuel injection strategy was developed to address the long ignition delay and high maximum pressure rise rate for the two gasoline fuels. Using the split fuel injection strategy, steady-state NOx sweeps were conducted at 1375 rpm with a load sweep from 5 to 15 bar BMEP. At 5 and 10 bar BMEP, both gasolines consistently exhibited lower soot levels than ULSD with the reduction more pronounced at 5 bar BMEP. 3-D CFD combustion simulation suggested that the higher volatility and lower viscosity of gasoline fuels can help improve the in-cylinder air utilization and therefore reduce the presence of fuel-rich regions in the combustion chamber.
2017-03-28
Technical Paper
2017-01-0690
Maziar Khosravi, Helmut Ruhland, Thomas Lorenz, Carsten Weber
Abstract The performance of boosted gasoline engines is limited at high loads by knock, stochastic Low Speed Pre-Ignition, and Megaknock. An investigation has been carried out on the occurrence of abnormal combustion and megaknock in a 1.6 L GTDI engine with the aim to determine the causes of such phenomena. A classification of abnormal combustion events and causes is presented in order to facilitate a consistent terminology. The experiments specifically focus on the effects of exhaust residual gas on occurrence of megaknock in multi-cylinder engines. The results showed that while a misfire will not lead to megaknock, a very late combustion in one cycle, in one cylinder may lead to megaknock in the following cycle in the same or adjacent cylinder. Additionally, a recently developed multi-zone model was used to analyze the role of residual gas on auto-ignition.
2017-03-28
Technical Paper
2017-01-0692
Haiying Li, Kun Wang, Lei Wang, Yufeng Li, Junting Fan
Abstract Due to increasingly stringent emission and fuel consumption regulations, diesel engines for vehicle are facing more and more technical challenges. Engine downsizing technology is the most promising measures to deal with these challenges at present. With the enhancement of power density, a small engine displacement with a high turbocharging technique becomes popular. In order to increase the intake mass flow rate on a downsizing diesel engine, the tilting axis of intake valve was chosen to enlarge the intake valve diameter and decrease the arc radius of intake ports. Thus cylinder head had to be redesigned to meet this demand. Geometry of cylinder head made a notable effect in organization of in-cylinder flow, fuel-air mixing quality and further combustion characteristics. 3-D CFD was a convenient and economical tool to explore effects of geometry of cylinder head on the combustion process.
2017-03-28
Technical Paper
2017-01-0721
Michele Bardi, Gilles Bruneaux, André Nicolle, Olivier Colin
Abstract This paper is a contribution to the understanding of the formation and oxidation of soot in Diesel combustion. An ECN spray A injector (single axial-oriented orifice) was tested in a well characterized high-temperature/high-pressure vessel at engine relevant conditions. The size of the test section (>70mm) enables to study the soot formation process in nearly free field conditions, which constitutes an ideal feature for fundamental understanding and model validation. Simultaneous high-speed OH* chemiluminescence imaging and high-speed 2D extinction were performed to link together the information regarding flame chemistry (i.e. lift-off length) and the soot data. The experiments were carried out for a set of fuels with different CN and sooting index (Diesel fuel, Jet fuel, gasoline and n-dodecane) performing parametric variations in the test conditions (ambient temperature and oxygen concentration).
2017-03-28
Technical Paper
2017-01-0717
Metin Korkmaz, Rene Zweigel, Kai Niemietz, Bernhard Jochim, Dirk Abel, Heinz Pitsch
Abstract For compliance with legislative regulations as well as restricted resources of fossil fuel, it is essential to further reduce engine-out emissions and increase engine efficiency. As a result of lower peak temperatures and increased homogeneity, premixed Low-Temperature Combustion (LTC) has the potential to simultaneously reduce nitrogen oxides (BSNOx) and soot. However, LTC can lead to higher emissions of unburnt total hydrocarbons (BSTHC) and carbon monoxide (BSCO). Furthermore, losses in efficiency are often observed, due to early combustion phasing (CA50) before top dead center (bTDC). Various studies have shown possibilities to counteract these drawbacks, such as split-injection strategies or different nozzle geometries. In this work, the combination of both is investigated. Three different nozzle geometries with included spray angles of 100°, 120°, and 148° and four injection strategies are applied to investigate the engine performance.
2017-03-28
Technical Paper
2017-01-0713
Håkan Persson, Aristotelis Babajimopoulos, Arjan Helmantel, Fredrik Holst, Elin Stenmark
Abstract The demands for a future diesel engine in terms of emission compliance, CO2 emissions, performance and cost effectiveness set new requirements for the development process of the combustion system. This paper focuses on the development of the next generation Volvo Cars diesel combustion system, which should comply with Euro 6d including Real Driving Emissions (RDE), with emphasis on the novel methods applied throughout the process. The foundation of a high performing combustion system is formed by first determining the requirements for the system, after which the key factors that affect system performance are selected, such as the charge motion, combustion chamber geometry and injector nozzle geometry. Based on the requirements, a robust charge motion with desired flow characteristics is defined. A new automated CFD optimization process for combustion chamber geometry and spray target is developed.
2017-03-28
Technical Paper
2017-01-0707
Srinivas Padala, Minh Khoi Le, Yoshihiro Wachi, Yuji Ikeda
Abstract The effect of microwave enhanced plasma (MW Plasma) on diesel spray combustion was investigated inside a constant volume high pressure chamber. A microwave-enhanced plasma system, in which plasma discharge generated by a spark plug was amplified using microwave pulses, was used as plasma source. This plasma was introduced to the soot cloud after the occurrence of autoignition, downstream of the flame lift-off position to allow additional plasma-generated oxidizers to be entrained into the hot combustion products. Planar laser induced incandescence (PLII) diagnostics were performed with laser sheet formed from 532 nm Nd:YAG laser to estimate possible soot reduction effect of MW plasma. A semi-quantitative comparison was made between without-plasma conventional diesel combustion and with-plasma combustion; with LII performed at different jet cross-sections in the combustion chamber.
2017-03-28
Technical Paper
2017-01-0708
Carlos Jorques Moreno, Ola Stenlaas, Per Tunestal
Abstract Factors influencing the effect of pilot-injection on main-injection combustion were investigated using heat release analysis in a heavy-duty diesel engine fuelled with standard diesel fuel, and included the effect of those factors on engine performance and emissions. Combinations of pilot injection parameters i.e. pilot start of injection, pilot mass, pilot-main injection separation, and rail pressure were studied for various operating conditions and combustion phases. It was concluded that the effect of pilot-injection combustion on main injection can be studied based on the phase of pilot combustion at the start of main injection. Four cases were identified: a) main injection during the mixing phase of pilot injection; b) main injection during the premixed phase of pilot combustion; c) main injection during the diffusive phase of pilot combustion and d) main injection after pilot combustion was completed.
2017-03-28
Technical Paper
2017-01-0797
Sahil Sane, Tamer Badawy, Naeim Henein
Abstract Cold starting problems of diesel engines are caused mainly by the failure of the auto-ignition process or the subsequent combustion of the rest of the charge. The problems include long cranking periods and combustion instability leading to an increase in fuel consumption in addition to the emission of undesirable unburned hydrocarbons which appear in the exhaust as white smoke. The major cause of these problems is the low temperature and pressure of the charge near the end of the compression stroke and/or the poor ignition quality of the fuel. This paper presents the results of an experimental investigation of cold starting of a high speed diesel engine with ULSD (Ultra Low Sulphur Diesel) and JP8 (Jet Propulsion) fuels at ambient temperature (25°C). A detailed analysis is made of the autoignition and combustion of the two fuels in the first few cycles in the cold start transient.
2017-03-28
Technical Paper
2017-01-0789
Tobias Johansson, Ola Stenlaas
Abstract Typically, the combustion in an internal combustion engine is open-loop controlled. The introduction of a cylinder pressure sensor opens the possibility to introduce a virtual combustion sensor. This virtual sensor is a possible enabler for closed-loop combustion control and thus the possibility to counteract the effects of engine part to part variation, component ageing and fuel quality diversity. The extent to which these effects can be counteracted is determined by the detection limits of the virtual combustion sensor. To determine the limitation of the virtual combustion sensor, a virtual combustion sensor system was implemented based on a one-zone heat-release analysis, including the signal processing of the pressure sensor input. The typical error sources in a heavy-duty engine were identified and quantified. The virtual combustion sensor system was presented with flawed signals and the sensor’s sensitivities to the errors were quantified.
2017-03-28
Technical Paper
2017-01-0788
Harshit Aggarwal, Akshit Goel, Harshil Kathpalia, Naveen Kumar
Abstract Rapid depletion in fuel resources owing to the low efficiency of current automobiles has been a major threat to future generations for fuel availability as well as environmental health. Advanced new generation of internal combustion (IC) engines are expected to have far better emissions levels both gaseous (NOx and CO) and particulate matter, at the same time having far lower fuel consumption on a wide range of operating condition. These criteria could be improved having a homogeneous combustion process in an engine. Homogeneous mixing of fuel and air in HCCI leads to cleaner combustion and lower emissions. Since peak temperatures are significantly lower than in typical SI engines, NOx levels and soot are reduced to some extent. Because of absence of complete homogeneous combustion but quasi homogeneous combustion present in HCCI, there is still a possibility of further reducing the emissions as well as enhancing the engine performance.
2017-03-28
Technical Paper
2017-01-0793
Tsutomu Kusuhara, Tatsuya Shinkai, Kazuki Yoshida, David Langley, Mitsunobu Kajitani
Abstract The history of the study to apply the ion current to gasoline engine control is so long, and many papers on modeling and application have been published so far. Especially, the study on modeling has been advanced, and it has become possible to estimate the ion current. And in the area of application, many papers have proposed the detection method of engine knock, pre-ignition, combustion stability and so on. However, there few results the proposed methods were put to the production engine. This paper proposes the internal exhaust gas recirculation (EGR) control system based on ion current which enables to set the limit value of internal EGR rate, so as to extract the best fuel efficiency of engine itself.
2017-03-28
Technical Paper
2017-01-0814
Daniel Ruth, Jacqueline O'Connor
Abstract The mixing of a diesel spray with in-cylinder gases is driven by both turbulent mixing during the free-jet penetration phase and by mixing during the jet’s impingement on surfaces such as the piston bowl. Current reduced order models, and many experiments, focus solely on the free-jet penetration phase, although jet-wall interaction occurs during a significant portion of the duration of a fuel injection in both small-bore and large-bore engines. A control volume-based model for the spreading of an impinging spray along a flat wall is presented as a first step towards capturing key jet processes during the impingement phase of fuel injection. Schlieren measurements of impinging gaseous jets are used to evaluate the model.
2017-03-28
Technical Paper
2017-01-0813
Yanzhe Sun, Kai Sun, Zhen Lu, Tianyou Wang, Mengqiu Jia
Abstract Matching fuel injection and airflow motion is critical for the optimization of fuel-air mixing and combustion process in diesel engines. In this study, the effects of swirl flow on liquid droplet motion and the selection of swirl ratio, which are known as the major concern in organizing airflow motion, were investigated based on theoretical analysis of droplet trajectories. The evaporating droplets with various initial conditions are assumed to be transported in a solid-body-like swirl field, and their trajectories were derived based on force analysis. To evaluate fuel-air mixing quality, a new parameter with respect to fuel vapor distribution was proposed. Based on this methodology, the effects of swirl velocity, droplet size, as well as liquid-gas density ratio on droplet trajectory were discussed under diesel-engine-like boundary conditions.
2017-03-28
Technical Paper
2017-01-0821
Qinglin Xu, Min Xu, David Hung, Shengqi Wu, Xue Dong, Hiroaki Ochiai, Zhisong Zhao, Caixia Wang, Kaiyue Jin
Abstract High fuel injection pressure has been regarded as a key controlling factor for internal combustion engines to achieve good combustion performance with reduced emissions and improved fuel efficiency. For common-rail injection system (CRS) used in advanced diesel engines, fuel injection pressure can often be raised to beyond 200 MPa. Although characteristics of diesel spray has been thoroughly studied, little work has been done at ultra-high injection pressures. In this work, the characteristics of CRS diesel spray under ultra-high injection pressure up to 250 MPa was investigated. The experiments were conducted in an optically accessible high-pressure and high-temperature constant volume chamber. The injection pressure varied from 50 MPa to up to 250 MPa. Both non-evaporating condition and evaporating condition were studied. A single-hole injector was specially designed for this investigation.
2017-03-28
Technical Paper
2017-01-0819
David van Bebber, Uwe Reuter
Abstract The fuel consumption and emissions of diesel engines is strongly influenced by the injection rate pattern, which influences the in-cylinder mixing and combustion process. Knowing the exact injection rate is mandatory for an optimal diesel combustion development. The short injection time of no more than some milliseconds prevents a direct flow rate measurement. However, the injection rate is deduced from the pressure change caused by injecting into a fuel reservoir or pipe. In an ideal case, the pressure increase in a fuel pipe correlates with the flow rate. Unfortunately, real measurement devices show measurement inaccuracies and errors, caused by non-ideal geometrical shapes as well as variable fuel temperature and fuel properties along the measurement pipe. To analyze the thermal effect onto the measurement results, an available rate measurement device is extended with a flexible heating system as well as multiple pressure and temperature sensors.
2017-03-28
Technical Paper
2017-01-0765
Shuojin Ren, Boyuan Wang, Jianhua Xiao, Haoye Liu, Zhi Wang, Jianxin Wang, Chuandong Li, Qingpeng Zhang
Abstract This research focuses on the potential of Homogeneous Charge Induced Ignition (HCII) combustion meeting the Euro V emission standard on a heavy-duty multi-cylinder engine using a simple after-treatment system. However, in our previous studies, it was found that the gasoline ratio was limited in HCII by the over-high compression ratio (CR). In this paper, the effects of reducing CR on the performances of HCII at medium and high loads were explored by experimental methods. It was found that by reducing CR from 18:1 to 16:1 the peak in-cylinder pressure and the peak pressure rise rate were effectively reduced and the gasoline ratio range could be obviously extended. Thus, the combustion and emission characteristics of HCII at medium and high loads were noticeably improved. Soot emissions can be significantly reduced because of the increase of premixed combustion ratio. The reduction could be over 50% especially at high load and high speed conditions.
2017-03-28
Technical Paper
2017-01-0767
Jayant Kumar Arora, Mahdi Shahbakhti
Abstract Real-time control of Reactivity Controlled Compression Ignition (RCCI) during engine load and speed transient operation is challenging, since RCCI combustion phasing depends on nonlinear thermo-kinetic reactions that are controlled by dual-fuel reactivity gradients. This paper discusses the design and implementation of a real-time closed-loop combustion controller to maintain optimum combustion phasing during RCCI transient operations. New algorithms for real-time in-cylinder pressure analysis and combustion phasing calculations are developed and embedded on a Field Programmable Gate Array (FPGA) to compute RCCI combustion and performance metrics on cycle-by-cycle basis. This cycle-by-cycle data is then used as a feedback to the combustion controller, which is implemented on a real-time processor. A computationally efficient algorithm is introduced for detecting Start of Combustion (SOC) for the High Temperature Heat Release (HTHR) or main-stage heat release.
2017-03-28
Technical Paper
2017-01-0764
Gabriele Di Blasio, Giacomo Belgiorno, Carlo Beatrice
Abstract The paper reports the results of an experimental campaign aimed to assess the impact of the compression ratio (CR) variation on the performance and pollutant emissions, including the particle size spectrum, of a single cylinder research engine (SCE), representatives of the engine architectures for automotive application, operated in dual-fuel methane-diesel mode. Three pistons with different bowl volumes corresponding to CR values of 16.5, 15.5 and 14.5 were adopted for the whole test campaign. The injection strategy was based on two injection pulses per cycle, as conventionally employed for diesel engines. The test methodology per each CR included the optimization of both 1st injection pulse quantity and intake air mass flow rate in order to lower as much as possible the unburned methane emissions (MHC).
Viewing 241 to 270 of 43695