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Viewing 1 to 30 of 39883
Technical Paper
2014-11-11
Yudai Yamasaki, Shigehiko Kaneko
Biomass resources have attracted attention for their ability to address global environmental problems and as a potentially clean source of energy. One method of using biomass resources is to supply gasified biomass, which is produced by either a thermochemical or a microbiological reaction, as a fuel for gas engines used in power generation. The problems with using gas fuels in a gas engine, especially syngas produced by a thermochemical reaction, are their lower heat content and the variation in the fuel components. In addition, the enthalpy of syngas has to be exploited to achieve a high thermal efficiency. If this gas is directly supplied to a spark-ignition (SI) engine, such high temperatures can cause knock. On the other hand, HCCI require a pre-mixture at a temperature of approximately 1000 K to achieve auto-ignition with hydrocarbon fuels. These aspects of HCCI engines avoid the knocking that occurs in SI engines using hot syngas. Ultra-lean combustion can be also realized with fuels with a low LHV that contain several non-combustible components, and the enthalpy of syngas contributes to realizing the high-temperature pre-mixture conditions enabling auto-ignition.
Technical Paper
2014-11-11
Stefan Krimplstätter, Franz Winkler, Roland Oswald, Roland Kirchberger
Graz University of technology has presented several applications of its 2-stroke LPDI (low pressure direct injection) technology in the previous years (SAE Paper No´s.: 2005-32-0098, 2006-32-0065, 2008-32-0059, 2010-32-0019). In order to improve the competitiveness of the 2-stroke LPDI technology, an air cooled 50cm³ scooter application has been developed. All previous applications have been liquid cooled. The application demonstrates the EURO 4 (2017) ability of the technology and shows that the 2S-LPDI technology can also be applied to low cost air-cooled engines. Hence the complete scooter and moped fleet can be equipped with this technology in order to fulfil on the one hand the emission standards and on the other hand the COP (conformity of production) requirements of Euro 4 emission stage. The paper will present the Euro 4 results of the scooter and describe the very simple conversion process of the existing carburetor engine to the LPDI version. Euro 4 results can be achieved with conventional exhaust system architecture known form nowadays Euro 2 applications.
Technical Paper
2014-11-11
Alexander K. Rowton, Joseph K. Ausserer, Keith D. Grinstead, Paul J. Litke, Marc D. Polanka
As internal combustion engines (ICEs) decrease in displacement, their cylinder surface area to swept volume ratio increases. Examining power output of ICEs with respect to cylinder surface area to swept volume ratio shows that there is a dramatic change in power scaling trends at approximately 1.5 cm-1. At this size, thermal quenching becomes the dominant thermal loss mechanism and performance and efficiency characteristics suffer. Furthermore, small ICEs (>1 cm-1) have limited technical performance data compared to ICEs in larger size classes. Therefore, it is critical to establish accurate performance figures for a family of geometrically similar engines in the size class of approximately 1.5 cm-1 in order to better predict and model the thermal losses as well as other phenomena that contribute to lower efficiencies in small ICEs. The engines considered in this scaling study were manufactured by 3W Modellmotoren, GmbH. In particular, they are the 3W-28i, 3W-55i, and 3W-85Xi which have a cylinder surface area to swept volume ratio of 1.81 cm-1, 1.46 cm-1, and 1.28 cm-1 respectively.
Technical Paper
2014-11-11
Joseph K. Ausserer, Alexander K. Rowton, Keith D. Grinstead, Paul J. Litke, Marc D. Polanka
In this work, in-cylinder pressure was measured in a 55 cc single cylinder, 4.4 kW, two stroke, spark ignition engine. Engines of this size are common in handheld power tools, hobbyist aircraft, and more recently, commercially developed remotely piloted aircraft operated by the government and military. Literature data on adapting performance measurements developed for larger engines to engines of this size is sparse. This work focuses on evaluating two different methods for measuring in-cylinder pressure, a critical parameter for combustion analysis, matching power plants to airframes, and engine optimization. In-cylinder pressure measurements were taken using two different pressure transducers to determine if the performance differences between the two transducers are discernible in a small, spark ignition engine. A Kistler brand measuring spark plug was compared to a Kistler brand flush mount high temperature pressure sensor. Both sensors employ a piezo-electric pressure sensing element and were designed to measure indicated mean effective pressure and to detect knock at high temperature engine conditions.
Technical Paper
2014-11-11
Federico Brusiani, Gian Marco Bianchi, Cristian Catellani, Marco Ferrari, Paolo Verziagi, Dario Catanese
Most of the handheld application are equipped with a Two stroke SI engine. The advantage of this engine are known but one of the problem of this applications is to design air cooling system with high efficiency. One of the main problem to cool the two stroke engine for hand held applications like chainsaw, brush cutter, blower and so on is obtain compact design of the application but in the mean time to have the correct air flow in all conditions. This paper describes a CFD methodology to optimize the air flow around the two stroke engine and identify the potential improvement of this system to increase the cooling efficiency.
Technical Paper
2014-11-11
Yoshimoto Matsuda
As for electric automobile, the mass production period has begun by the rapid progress of the battery performance. But for the electric motor cycle(MC), it is limited for the venture companies’ releases. To study the feasibility of the electric MC, we developed the prototypes in the present technical and suppliers’ environments and evaluated them by the practical view points. The developed electric MC has the equivalent driving performance of the 250cc inner combustion engine(ICE) MC and a cruising range of 100km in normal use. In the prototype development, the reliability and the ability of protection design of the battery in the whole vehicle against the environmental loads are mainly studied, especially, fever and cold, water, shock, and the accident impact. In addition, it is carried out the performance improvement by the heat management design of the motor to meet the practical use condition. From the usage points as MC, we developed the function of the 4-speeds dog gear MT and its electric control, reward ride function, the regenerative brake control, and the quick charge.
Technical Paper
2014-11-11
Hans-Juergen Schacht, Manuel Leibetseder, Niko Bretterklieber, Stephan Schmidt, Roland Kirchberger
Title: Control of a Low Cost Range Extender for L1e class PHEV two-wheelers Authors: Schacht, Bretterklieber, Schmidt, Kirchberger Affiliation: Institute for Internal Combustion Engines and Thermodynamics, Graz University of Technology Due to the small number of two wheelers in Europe and their seasonal use, their contribution to the total emissions has been underestimated for a long time. With the implementation of the new emission regulation 168/2013 coming into force 2016 for type approval, the two wheeler sector is facing major changes. The need to fulfil more stringent emission limits and the high demand on the durability of after treatment systems result in an engine control system that is getting more complex and thus costlier. Especially the low cost two wheelers with small engine capacities will be affected by increasing costs which cannot be covered be the actual competitive product price. Therefore, new vehicle concepts are likely to appear on the market. A vehicle concept of a plug in hybrid electric city scooter with range extender as well as the range extender itself have already been published in SAE Papers 2011-11-08 and 2012-10-23.
Technical Paper
2014-11-11
Luigi Allocca, Alessandro Montanaro, Rita Di Gioia, Giovanni Bonandrini
In the next future, improvements of direct injection systems for spark-ignited engines are necessary for the potential reductions in fuel consumptions and exhaust emissions. The admission and spread of the fuel in the combustion chamber is strictly related to the injector design and performances, such as to the fuel and environmental pressure and temperature conditions. In this paper the spray characterization of a GDI injector under normal and flash-boiling injection conditions has been investigated. A customized sensing of the injector nose permitted the temperature control of the nozzle up to 90 °C while a remote-controlled thermostatic device allowed the fuel heating from ambient to 120 °C. An axially-disposed, 0.200 mm in diameter, single-hole injector has been used with l/d ratio equal to 1 and static flow@100 bar: 2.45 g/s, using iso-octane as mono-component fluid. A 1.0 ms duration single pulse strategy has been adopted at the injection pressure of 10 MPa. The spray evolved in a quiescent optically-accessible vessel pressurize at 0.05, 0.1 and 0.3 MPa at ambient temperature of the gas (N2).
Technical Paper
2014-11-11
Francesco Catapano, Silvana Di Iorio, Paolo Sementa, Bianca Maria Vaglieco, Marcello Fiaccavento, Francesco Giari, Antonio Marchetti
This paper deals with the investigation of anomalous phenomena during the cranking phase of a spark ignition small engine, in particular backfire. The growing interest of this abnormal combustion is due to the use of fuels with different chemical-physical properties with respect to gasoline, that can affect especially the cranking phase of the engine. In this work the influence of the composition of the fuel on backfire was studied. In particular the investigation was focused on the presence of ethanol in the fuel. The experimental activity was carried out in an optically accessible engine derived from a 4-stroke spark ignition engine for two-wheel application. The test bench was instrumented and adapted in order to simulate the engine conditions similar to the ones that lead to the anomalous auto-ignition in the intake duct during the reverse rotation of the engine. Two different test procedures have been developed with the aim of promoting the auto-ignition at the intake. All the major engine parameters were measured, such as the in-cylinder pressure, the pressure at the exhaust and at the intake; in order to characterize the engine condition and to monitor the auto-ignition.
Technical Paper
2014-11-11
Ken Fosaaen
Global concerns over pollution have led to increasingly strict emissions legislation targeting small engines, which currently pollute at a much greater level than modern multi-cylinder automotive engines. Closed-loop control may be required to meet many future legislation requirements; however, such systems can be impractical due to high added component costs. A necessary component for closed-loop engine control is an oxygen sensor. Existing automotive oxygen sensors are too large, require too much power, and far too expensive to be suitable for the vast majority of the global small engine applications; therefore, some manufacturers have developed smaller and/or unheated versions based on their existing sensors to meet this emerging need. The ability to miniaturize resistive based sensors well below that of traditional Nernst (zirconia based) oxygen sensors affords the opportunity to meet future emissions standards with less of an impact on cost. The performance of a novel low-cost, low-power narrow-band oxygen sensor was compared with several automotive as well as newer oxygen sensors developed for the small engine market.
Technical Paper
2014-11-11
Giuseppe Danilo Rossi, Sara Gronchi, Matteo Gasperini, Bernardo Celata, Raffaele Squarcini
Electrical oil pumps are used in order to reduce the engine car emissions thanks to the optimization of the absorbed energy and motor efficiency. The present trend to obtain this improvement of the motor efficiency is the electrification of the auxiliary components that can be driven independently from the engine shaft. In this field, the electrical oil pumps are one of the most required components used for automatic transmissions as well as for the main lubrication system. An electrical oil pump is driven by an electric motor with its electronic control system. The electric motor should generate an available torque higher than the total torque requested by the hydraulic mechanism, to allow the pump generating the expected performances. The pump type has been chosen thanks to PPT experience in the development of hydraulic pumps, the “G-rotor” solution, which is a particular shape of gears, is the best compromise in terms of noise, dimensions, robustness and packaging. In order to design an optimized electrical oil pump it is important to evaluate the absorbed torque by the hydraulic mechanism.
Technical Paper
2014-11-11
Ryutaro Shinohara
We have tentatively manufactured the prototype model of exhaust heat recovery heat exchanger and carried out the heat transfer and pressure drop performance tests on it. This prototype (P.T.) is characterized that the overall heat transfer coefficient is less affected by the change of the hot air mass flow rate than that of the mass-produced model (M.P.) and overall heat transfer coefficient of the prototype exceeds that of the mass-produced under the Rel range of 1500. We have found that the changes of overall heat transfer coefficient are caused by the variation of the thermal resistance of hot air side and the thermal resistance consists of the fin effective heat transfer coefficient and the tube hot air side heat transfer coefficient from equation of the thermal conductance. We have calculated the fin effective heat transfer coefficient using Pohlhausen equation and fin efficiency, and obtained the tube hot air side heat transfer coefficient from the test results. We have compared these coefficients and found that the fin effective heat transfer coefficient of the prototype is much lower, but the tube hot air side heat transfer coefficient of the prototype is much higher than that of the mass-produced.
Technical Paper
2014-11-11
Ken Fosaaen
Global concerns over pollution have led to increasingly strict emissions legislation targeting small engines, which currently pollute at a much greater level than modern multi-cylinder automotive engines. Closed-loop control may be required to meet many future legislation requirements; however, such systems can be impractical due to high added component costs. A necessary component for closed-loop engine control is an oxygen sensor. Existing automotive oxygen sensors are too large, require too much power, and far too expensive to be suitable for the vast majority of the global small engine applications; therefore, some manufacturers have developed smaller and/or unheated versions based on their existing sensors to meet this emerging need. The ability to miniaturize resistive based sensors well below that of traditional Nernst (zirconia based) oxygen sensors affords the opportunity to meet future emissions standards with less of an impact on cost. In this study, a sub-miniature resistance-based narrowband oxygen sensor was developed and its response to various exhaust lambda values was characterized at various temperatures.
Technical Paper
2014-11-11
Stefania Falfari, Claudio Forte, Federico Brusiani, Gian Marco Bianchi, Giulio Cazzoli, Cristian Catellani
Faster combustion and lower cycle-to-cycle variability are the two mandatory tasks in the naturally aspirated engines for lowering the emission levels and for increasing the efficiency. Generally speaking the promotion of a stable and coherent tumble structure is largely believed in literature to enhance the in-cylinder turbulence accelerating combustion process. In small PFI engine layout and weight constraints limit the adoption of more advanced concepts. The turbulence generation process is strictly related to the tumble vortex deformation process: during the compression stroke the tumble vortex is deformed, accelerated and its breakdown in smaller eddies leads to the turbulence enhancement process. The prediction of the final level of turbulence for a particular engine operating point is crucial during the engine design process because it represents a practical comparative means for different engine solutions. The tumble ratio parameter value represents a first step toward the evaluation of the turbulence level at ignition time, but it has an intrinsic limit.
Technical Paper
2014-11-11
Henning Heikes, Christian Steinbrecher, Bastian Reineke, Jürgen Berkemer, Thorsten Raatz, Wolfgang Fischer
Cost reduction of engine management systems (EMS) for two-wheeler applications is the key to utilize their potentials compared to carburetor bikes regarding emissions, fuel economy and system robustness. In order to reduce the costs of a system with port fuel injection (PFI) Bosch is developing an EMS without a manifold air pressure (MAP) sensor. The pressure sensor is usually used to compensate for different influences on the air mass, which cannot be detected via the throttle position sensor (TPS) and mean engine speed. Such influences are different leakage rates of the throttle body and changing ambient conditions like air pressure. Bosch has shown in the past that a virtual sensor relying on model based evaluation of engine speed can be used for a detection of leakage air mass in idling to improve the pre-control of the air-fuel ratio. This provides a functionality which so far was only possible with an intake pressure sensor. In this paper the air mass calculated from the model based engine speed evaluation is used to adapt the influence of ambient pressure changes e.g. because of different altitudes.
Technical Paper
2014-11-11
Ryosuke Ibata, Hirotaka Kawatsu, Tetsuya Kaneko, Kenji Nishida
Motorcycles with small displacement engines (hereafter called small motorcycles) are used in large numbers and the improvement of the fuel economy is one of the important issues to be solved from the global environmental viewpoint. Spark advance control is one of the technologies for fuel economy improvements. To apply this technology, it generally requires being equipped with a throttle position sensor to detect engine loads. However, many of these small motorcycles cannot be equipped with a throttle position sensor because of their stringent requirements for affordable prices. Meanwhile, the onboard technology for estimating engine loads has been developed by using “Δω” (delta-omega), which represents the amplitude of variations in crankshaft angular velocity within a four-stroke cycle. This study aimed at the achievement of the system that could substitute for a throttle position sensor, which outputs an on-off signal to distinguish the engine load levels into two ranges (hereafter called throttle switch), using engine load estimation technology based on Δω.
Technical Paper
2014-11-11
Klaus Stuhlmüller
In a microcontroller-operated ignition process, the combustion is dependent on three important criteria: Spark burn duration, ignition voltage, and ignition spark energy. These criteria must be adapted exactly to the engine's individual requirement profile to ensure optimal combustion. In each operating state and operating environment, optimum ignition is ensured by continuously analyzing sensor values. Engine manufacturers continue to be faced with the challenge of ensuring that the machine runs as smoothly and quietly as possible. Increased spark duration and higher energy of the ignition spark enable improved combustion of the gasoline-air mixture in the combustion compartment. This article describes an electrical ignition process using an array of multiple coils and a magnetic generator that is rotating in sync with the machine. During this process the magnetic field temporarily flows through the coils and generates a sequence of magnetic flow variations per rotation. This induces corresponding half-waves of alternating voltage in the coils of the ignition module.
Technical Paper
2014-11-11
Daniela Siano, Fabio Bozza, Danilo D'Agostino, Maria Antonietta Panza
In the present work, an Auto Regressive (AR) model and a Discrete Wavelet Transform (DWT) are applied on vibrational signals, acquired by an accelerometer placed on the cylinder block of an internal combustion engine, for knock detection purposes. To this aim, vibrational signals are acquired on a four cylinder Spark Ignition engine for different engine speeds and spark advances. The same analysis is executed by also using the traditional MAPO (Maximum Amplitude of Pressure Oscillations) index, applied on the in-cylinder pressure waveforms. The results of the three methods are compared and in depth discussed to the aim of highlighting the pros and cons of each methodology. In particular, the problem of fixing a constant threshold level for each running condition is afforded and solved. The examples presented show the capability of the vibration based detection algorithms in accurately monitor the presence of heavy or soft knock phenomena, and to determine its intensity. Therefore, the possibility of implementation in modern on-board control units is foreseen, as well.
Technical Paper
2014-11-11
Christian Steinbrecher, Bastian Reineke, Wolfgang Fischer, Henning Heikes, Thorsten Raatz
Equipping low cost 2-wheelers with engine management systems (EMS) enables not only a reduction of emissions but also an improvement in fuel consumption and system robustness. These benefits are accompanied by initially higher system costs compared to carburetor systems. In order to reduce the system costs, intelligent software solutions are developed at Bosch, which enable a reduction of the necessary sensors for a port fuel injection system (PFI) and furthermore provide new possibilities for combustion control. One example for these intelligent software solutions is model based evaluation of the engine speed signal. By use of the information in this signal, characteristic features like air charge, indicated mean effective pressure (imep) and combustion phasing are derivable. The present paper illustrates how these features could be used to reduce the system costs and how to improve the fuel consumption and system robustness. Especially in the low cost segment the system robustness is challenged by significant bike-to-bike variations in e.g. compression ratio or valve timing.
Technical Paper
2014-11-11
Yuta Kugimachi, Yusuke Nakamura, Norimasa Iida
Homogeneous Charge Compression Ignition (HCCI) engine has several advantages of high thermal efficiency and low emission over the conventional Spark Ignition (SI) engine and Compression Ignition (CI) engine. Although one way to achieve higher loads without knocking in HCCI engine is the combustion phasing retard, it is difficult to control a combustion-phasing since there is no external combustion trigger for controlling ignition like spark ignition and diesel fuel injection. Futhermore, recent researches show that too much combustion-phasing retard leads to unacceptable cycle-to-cycle variation of Pressure Rise Rate (PRR) and Indicated Mean Effective Pressure (IMEP). Therefore, it is necessary to construct a HCCI combustion control system to control a combustion-phasing at constant phasing in the expansion stroke accurately to get the high load without knocking. This study investigates the HCCI combustion control system and the algorithm as a means of extending the limit of IMEP of HCCI combustion at high load for realize HCCI engine fuelled with Dimethyl Ether (DME).
Technical Paper
2014-11-11
Bo-Chiuan Chen, Yuh-Yih Wu, Wen-Han Tsai, Hsien-Chi Tsai, Huang-Min Lin, Yao-Chung Liang
Fuel film dynamics in the intake manifold are considered to develop air fuel ratio (AFR) control strategy with on-line system identification for a V2 engine in this paper. A1000 cc four-stroke two-cylinder, water-cooled port injection SI engine is used as the target engine to develop the engine model in Matlab/Simulink. The model which consists of charging, fueling, combustion, friction, and engine rotational dynamics is used to verify the proposed AFR control. Since the fuel film dynamics changes with different engine operating conditions, the fuel film parameters are often listed as look-up tables for fuel film dynamics calculation in the conventional AFR control. However, those parameters might be inaccurate during transient engine operation. Different intake port temperature will affect the accuracy of those fuel film parameters as well. In order to solve this problem, recursive least square (RLS) is used to identify those parameters on-line. Kalman filter is utilized to estimate the AFR using a narrow-band oxygen sensor.
Technical Paper
2014-11-11
Paolo Gai, Francesco Esposito, Riccardo Schiavi, Marco Di Natale, Claudio Diglio, Michele Pagano, Carlo Camicia, Luca Carmignani
The design and development of the electronic architecture and the control software integrated inside the next generation of two wheelers will be one of the major challenges for small engine products. The need for optimal fuel consumption and emission control, paired with strict safety requirements will force many manufacturers to reconsider their electronic architecture adding complex functions with the risk of incurring in additional costs to be carefully planned in the product roadmap. These challenges have already been tackled twenty years ago by the automotive manufacturers, generating a set of standards in an attempt to improve productivity and quality by standardization, interoperability and competition on functional content. The result has been the development of distributed software architectures based on the CAN bus and the OSEK/VDX[8] standard, and more recently with the AUTOSAR[4] initiative. Therefore, a set of automotive standards are available and can be used as an inspiration as they share common goals such as portability, reusability, and limited footprint; on the other side, the inherent complexity and license cost of complete commercial bundles makes the adoption of these automotive standards impracticable for low-cost engines.
Technical Paper
2014-11-11
Horizon Walker Gitano, Ray Chim, Jian Loh
Recent concern over air quality has lead to increasingly stringent emissions regulations on ever smaller displacement engines, resulting in the application of Electronic Fuel Injection to the 100cc-200cc class 2-wheelers in many countries. In the pursuit of ever smaller and less expensive EFI systems, a number of unique technologies are being explored, including resistive type oxygen sensors. In this paper we investigate the application of a small resistive oxygen sensor to a small motorcycle EFI system. Measurements of the exhaust system temperatures, and Air/Fuel Ratio ranges are carried out, and compared to the sensors response over this range to create an estimate of the sensors in-use performance. Actual sensor and temperature measurements are then compared to both a standard zirconia switching type oxygen sensor, and a wide-band oxygen sensor. Results are analyzed and indicate that the resistive type oxygen sensor should be capable of allowing the EFI controller to successfully control the vehicles AFR in all operating modes with a faster “light off” time, and lower overall current draw when compared to the standard heated zirconia sensor.
Technical Paper
2014-11-11
Hiroki Ikeda, Norimasa Iida, Hiroshi Kuzuyama, Tsutomu Umehara, Takayuki Fuyuto
A combustion method called Noise Cancelling Spike (NC-Spike) Combustion has been reported in the co-author’s previous paper, which reduces combustion noise in pre-mixed charge compression ignition (PCCI) with split injection. This NC-Spike Combustion uses interference of the following “spike” of pressure rise (heat release) on the preceding peak of pressure rise. The overall combustion noise was reduced by lowering the maximum frequency component of the noise spectrum. The period of this frequency is two times of the time interval between the two peaks of the pressure rise rate. This maximum load range of conventional PCCI combustion is limited by the combustion noise, since the maximum pressure rise rate increases as the amount of injected fuel increases. The NC-Spike Combustion has a potential to extend of the operating range of PCCI combustion. In this paper, we investigates feasibility and controllability of the two-peak heat release rate during high temperature heat release by adding fuel in the adiabatic compression process of pre-mixed gas.
Technical Paper
2014-11-11
Francisco Payri, José Javier Lopez, Benjamin Pla, Diana Graciano Bustamante
Direct injection compression ignited (CI) engines are today’s most efficient engine technology, granting efficiencies exceeding 40% for their optimal operation point. In addition, a strong technological development has allowed the CI engine to overcome its traditional weak points: both its pollutant emissions and the gap in specific power regarding its competitor, i.e. the spark ignited engine, have been noticeably reduced. Particularly, the increase in specific power has leaded to the downsizing as an effective method to improve vehicle efficiency. However, the cylinder displacement in current CI engines is barely lower than 0.4 liters and authors do not know any CI engine with a cylinder displacement lower than 0.25 liters. For some applications (urban light duty vehicles, Range Extenders...) it may be interesting to reduce the engine displacement to address power targets around 20kW with high efficiencies. This paper assesses the thermo- and fluid-dynamic limitations which make challenging extending the application of automotive CI engines to the low power region, namely, space limitations for injection and combustion processes, increase of surface-to-volume ratio giving rise to higher heat losses and limits related to the air management, most notably with turbocharging, due to the reduction in turbocharger efficiency with decreasing size.
Technical Paper
2014-11-11
Giancarlo Chiatti, Erasmo Recco, Ornella Chiavola, Silvia Conforto
In the last years environmental issues of IC engines have promoted the need to assess new strategies in order to obtain a reduction not only of pollutants emission in atmosphere, but also of noise radiation. Engine noise can be classified into aerodynamic noise of intake and exhaust systems and surface radiated noise. Sources identification and analysis is essential to evaluate the individual contribution (injection, combustion, piston slap, turbocharger, oil pump, valves) to the overall engine noise with the aim of selecting appropriate noise reduction strategies. In previous papers, the attention was addressed towards the combustion related noise emission. The research activity was aimed at selecting the optimal placement for the microphone in which the signal was characterized by a strong correlation with the in-cylinder pressure development during the combustion process. The analysis and the processing of the sound emission allowed to isolate the acoustic contribution mainly due to the combustion event.
Technical Paper
2014-11-11
Mohd Al-Hafiz Mohd Nawi, Yoshiyuki Kidoguchi, Misato Nakagiri, Naoya Uwa, Yuzuru Nada, Seiji Miyashiro
High boosting technology is commonly applied to diesel engines in recent years. One the other hand, the study of spray behavior at ignition delay period is still an important role in diesel combustion. This study is focused on effect of ambient condition on diesel spray during ignition delay period. The study investigates both macro-scale and micro-scale dynamic behaviors of diesel spray affected by ambient density and temperature at early stage of injection. The experiment uses dual nano-spark shadowgraph method and rapid compression machine with constant volume chamber to understand dynamic behavior of evaporation diesel spray. This technique enables to capture images of both macro- and micro-scale structure of diesel spray using a still camera. Further, this system has two sparks that send high intensity light toward spray. When the sparks produce the luminescence at short time interval, images of the same diesel spray at different timing can be captured on separated films. The images show droplets formation, atomization and evaporation at spray boundary.
Technical Paper
2014-11-11
Keiya Nishida, Kuichun LI, Takeru Matsuo, Daisuke Shimo, Wu Zhang
Spray characteristics under very small injection amount injected by the hole-type nozzle for a D.I. Diesel engine were investigated using the spray tes rig consisting a high-pressure and high-temperature constant volulme vessel with optical accesses and a common rail injectino system. The Laser Absorption Scattering (LAS) technique was used to visualize the liquid and vapor phase distributions in the evaporating spray. In the very small injection amount condition of the evaporating and free (no wall impingement) spray, the both spray tip penetration and spray angle are larger than those of the non-evaporating free spray. This tendency contradicts the previous observation of the Diesel spray with large injection amount and the quasi steady state momentum theory. In the case of the spray impinging on a 2-dimensional piston cavity wall, the spray tip penetration of the evaporating spray is larger than that of the non-evaporating spray. Discussion was made on the mechanisms behind these spray behaviors.
Technical Paper
2014-11-11
Yuzuru Nada, Yusuke Komatsubara, Thang Pham, Fumiya Yoshii, Yoshiyuki Kidoguchi
In this study, we investigated relationship between flame behaviors and NOx emissions using a rapid compression machine incorporating a small combustion chamber with a bore diameter of 60 mm and a displaced volume of 100 cc. A total gas sampling device was used to measure the NOx concentration in total gases existing in the combustion chamber at a designated time, which allows the evaluation of NOx production rate in combustion process. Temporal temperature distributions in the chamber were measured with high speed 2-color thermometry. Two types of injectors with 4 and 8 injection holes were used in the experimental trials. Gas oil (JIS #2) was used as the fuel, and injected into the chamber at pressures of 100 MPa and 160 MPa. Ambient pressures at fuel injection timing were set to 4 MPa and 8 MPa in order to investigate the effect of supercharging on combustion behaviors in the chamber. The temperature of ambient air was kept constant at 850 K in all experimental trials. A NOx concentration measured with the total gas sampling device increases at a stage of diffusion combustion following after a premixed combustion stage.
Technical Paper
2014-11-11
Jens Steinmill, Ralf Struzyna
Authors: Dipl.-Ing. Jens Steinmill, Dipl.-Ing. Ralf Struzyna, Prof.Dr.-Ing. Wolfgang Eifler Department for Combustion Engines, Ruhr-University Bochum , D-44801 Bochum, Germany Contact: e-mail: Jens.Steinmill@rub.de | phone: +49234-3227404 | fax: +49234-3207404 The control and regulation of internal combustion engines for use in nano-CHP units has not yet reached the state of the art, which is common in the automotive industry. Frequently, the engines are operated in a stationary operating point without adjustment of the combustion process. In the automotive sector is the torque structure prior art. The requested torque by driver, which is derived from the accelerator pedal position is coordinated with the other torque requests and converted in the simplest case, into a desired air-charge, ignition angle and amount of fuel. The actuators on the engine, for example, Throttle, ignition and injectors are triggered. At a nano-CHP unit, the target size of the motor controller is is not mechanical torque, but thermal and mechanical power.
Viewing 1 to 30 of 39883