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Viewing 1 to 30 of 195
2017-06-05
Technical Paper
2017-01-1792
Magnus Knutsson, Erik Kjellson, Rodney Glover, Hans Boden
Abstract Increased demands for reduction of fuel consumption and CO2 emissions are driven by the global warming. To meet these challenges with respect to the passenger car segment the strategy of utilizing IC-engine downsizing has shown to be effective. In order to additionally meet requirements for high power and torque output supercharging is required. This can be realized using e.g. turbo-chargers, roots blowers or a combination of several such devices for the highest specific power segment. Both turbo-chargers and roots blowers can be strong sources of sound depending on the operating conditions and extensive NVH abatements such as resonators and encapsulation might be required to achieve superior vehicle NVH. For an efficient resonator tuning process in-duct acoustic source data is required. No published studies exists that describe how the gas exchange process for roots blowers can be described by acoustic sources in the frequency domain.
2017-06-05
Technical Paper
2017-01-1790
Vinayak H. Patil, Ravi Kumar Sara, T. R. Milind, Rodney C. Glover
Abstract Vehicle noise emission requirements are becoming more stringent each passing year. Pass-by noise requirement for passenger vehicles is now 74 dB (A) in some parts of the world. The common focus areas for noise treatment in the vehicle are primarily on three sub-systems i.e., engine compartment, exhaust systems and power train systems. Down- sizing and down- speeding of engines, without compromising on power output, has meant use of boosting technologies that have produced challenges in order to design low-noise intake systems which minimize losses and also meet today’s vehicle emission regulations. In a boosted system, there are a variety of potential noise sources in the intake system. Thus an understanding of the noise source strength in each component of the intake system is needed. One such boosting system consists of Turbo-Super configuration with various components, including an air box, supercharger, an outlet manifold, and an intercooler.
2017-03-28
Technical Paper
2017-01-1035
Xingyu Xue, John Rutledge
Abstract Diesel engine downsizing aimed at reducing fuel consumption while meeting stringent exhaust emissions regulations is currently in high demand. The boost system architecture plays an essential role in providing adequate air flow rate for diesel fuel combustion while avoiding impaired transient response of the downsized engine. Electric Turbocharger Assist (ETA) technology integrates an electric motor/generator with the turbocharger to provide electrical power to assist compressor work or to electrically recover excess turbine power. Additionally, a variable geometry turbine (VGT) is able to bring an extra degree of freedom for the boost system optimization. The electrically-assisted turbocharger, coupled with VGT, provides an illuminating opportunity to increase the diesel engine power density and enhance the downsized engine transient response.
2017-03-28
Technical Paper
2017-01-1037
Christoph Haidinger, Wolfgang Kriegler, Adrian Millward-Sadler, Philipp Eder
Abstract This paper introduces an improved design for pressure wave superchargers used in recreational vehicles (RV) such as motorbikes or snowmobiles equipped with smaller engines. A pressure wave supercharger (PWS), commonly known as Comprex (or Hyprex), is generally used to lower the emissions. Additionally, in comparison to a standard turbocharger (TC) system, a PWS system demonstrates superior torque response behavior. However, a major disadvantage of the Comprex are its high noise emissions and expensive manufacture. For this reason, the goal of this study was to eliminate these shortcomings and to propose a new design for a pressure wave supercharger, which is simple and relatively inexpensive to produce. In this paper, the conceptual design development of this new type of PWS is presented. The methods used were the evaluation of an existing Comprex’s design and computational fluid dynamics (CFD) simulations.
2017-03-28
Technical Paper
2017-01-1039
Xinguo Lei, Mingxu Qi, Harold Sun, Xin Shi, Liangjun Hu
Abstract Radial flow Variable Nozzle Turbine (VNT) enables better matching between the turbocharger and engine. At partial loading or low-end engine operating points, the nozzle vane opening of the VNT is decreased to achieve higher turbine efficiency and transient response, which is a benefit for engine fuel consumption and emission. However, under certain small nozzle opening conditions (such as nozzle brake and low-end operating points), strong shock waves and strong nozzle clearance flow are generated. Consequently, strong rotor-stator interaction between turbine nozzle and impeller is the key factor of the impeller high cycle fatigue and failure. In present paper, flow visualization experiment is carried out on a linear turbine nozzle.
2017-03-28
Journal Article
2017-01-1040
Bertrand Kerres, Mihai Mihaescu, Matthieu Gancedo, Ephraim Gutmark
Abstract The compressor surge line of automotive turbochargers can limit the low-end torque of an engine. In order to determine how close the compressor operates to its surge limit, the Hurst exponent of the pressure signal has recently been proposed as a criterion. The Hurst exponent quantifies the fractal properties of a time series and its long-term memory. This paper evaluates the outcome of applying Hurst exponent based criterion on time-resolved pressure signals, measured simultaneously at different locations in the compression system. Experiments were performed using a truck-sized turbocharger on a cold gas stand at the University of Cincinnati. The pressure sensors were flush-mounted at different circumferential positions at the inlet of the compressor, in the diffuser and volute, as well as downstream of the compressor.
2017-03-28
Technical Paper
2017-01-0640
Robert Wade, Steven Murphy, Paul Cross, Craig Hansen
Abstract The Variable Displacement Supercharger (VDS) is a twin helical screw style compressor that has a feature to change its displacement and its compression ratio actively during vehicle operation. This device can reduce the parasitic losses associated with supercharging and improve the relative fuel economy of a supercharged engine. Supercharging is a boosting choice with several advantages over turbocharging. There is fast pressure delivery to the engine intake manifold for fast engine torque response providing the fun to drive feel. The performance delivered by a supercharger can enable engine fuel economy actions to include engine downsizing and downspeeding. The cost and difficulty of engineering hot exhaust components is eliminated when using only an air side compressor. Faster catalyst warm up can be achieved when not warming the turbine housing of a turbocharger.
2017-03-28
Journal Article
2017-01-0646
Michael Bassett, Jonathan Hall, Tony Cains, Mark Underwood, Richard Wall
Abstract Gasoline engine downsizing is already established as a technology for reducing vehicle CO2 emissions. Further benefits are possible through more aggressive downsizing, however, the tradeoff between the CO2 reduction achieved and vehicle drivability limits the level of engine downsizing currently adopted by vehicle manufacturers. This paper will present the latest results achieved from a very heavily downsized engine, and resulting demonstrator vehicle, featuring eSupercharging in combination with a conventional turbocharger. The original 1.2 litre, 3-cylinder, MAHLE downsizing engine has been re-configured to enable a specific power output in excess of 160 kW/litre. Of key importance is a cost effective, efficient and flexible boosting system.
2016-11-08
Technical Paper
2016-32-0078
Mark R. Mataczynski, Paul Litke, Benjamin Naguy, Jacob Baranski
Abstract Aircraft engine power is degraded with increasing altitude according to the resultant reduction in air pressure, temperature, and density. One way to mitigate this problem is through turbo-normalization of the air being supplied to the engine. Supercharger and turbocharger components suffer from a well-recognized loss in efficiency as they are scaled down in order to match the reduced mass flow demands of small-scale Internal Combustion Engines. This is due in large part to problems related to machining tolerance limitations, such as the increase in relative operating clearances, and increased blade thickness relative to the flow area. As Internal Combustion Engines decrease in size, they also suffer from efficiency losses owing primarily to thermal loss. This amplifies the importance of maximizing the efficiency of all sub-systems in order to minimize specific fuel consumption and enhance overall aircraft performance.
2016-11-08
Technical Paper
2016-32-0077
Roland Baar, Valerius Boxberger, Maike Sophie Gern
Abstract Two-cylinder engines not only have special demands concerning uniformity and dynamics of oscillating masses and firing order, but also place very different demands on the turbocharger. With two-cylinder engines, the pulsating influence grows and changes the operation of the turbine. In this paper different boosting technologies are compared in small engine applications. Besides turbochargers the potentials and limits of superchargers and electric chargers are compared as well as their combinations. These technologies show differences concerning power supply, operation range and efficiency, and these effects have different implications in small engines. The efficiency of a turbo compressor, for example decreases, rapidly for small dimensions. Results from experiments and engine process simulations are shown based on a two-cylinder engine of 0.8l displacement. The operating condition of a turbocharger turbine in a two-cylinder engine is very specific due to exhaust pulsations.
2016-11-08
Technical Paper
2016-32-0009
Yuki Takamura, Takahiro Shima, Hirotaka Suzuki, Keito Agui, Akira Iijima, Hideo Shoji
Homogeneous Charge Compression Ignition (HCCI) combustion has attracted widespread interest as a combustion system that offers the advantages of high efficiency and low exhaust emissions. However, it is difficult to control the ignition timing in an HCCI combustion system owing to the lack of a physical means of initiating ignition like the spark plug in a gasoline engine or fuel injection in a diesel engine. Moreover, because the mixture ignites simultaneously at multiple locations in the cylinder, it produces an enormous amount of heat in a short period of time, which causes greater engine noise, abnormal combustion and other problems in the high load region. The purpose of this study was to expand the region of stable HCCI engine operation by finding a solution to these issues of HCCI combustion.
2016-10-17
Technical Paper
2016-01-2340
Bin Mao, Mingfa Yao, Zunqing Zheng, Haifeng Liu
Abstract An experimental study is carried out to investigate the coupling between dual loop EGR (DL-EGR) and variable geometry turbocharger (VGT) on a heavy-duty commercial diesel engine under different operating conditions and inlet conditions. The effects of VGT rack position and high-pressure (HP) proportion in DL-EGR on engine performance and emissions are studied. The boosting system is a series 2-stage turbocharger with a VGT as the HP-stage. The HP-Proportion in DL-EGR is swept from 0% to 100% while several intake pressure values and EGR rates are fixed by adjusting the VGT position. Results demonstrate that the VGT and HP EGR both have great influence on the exhaust enthalpy and turbocharger efficiency. The exhaust enthalpy and the intake demand have great influence on the DL-EGR split strategy.
2016-10-17
Technical Paper
2016-01-2339
Xue-Qing Fu, Bang-Quan He, Hua Zhao
Abstract Engine downsizing can effectively improve the fuel economy of spark ignition (SI) gasoline engines, but extreme downsizing is limited by knocking combustion and low-speed pre-ignition at higher loads. A 2-stroke SI engine can produce higher upper load compared to its naturally aspirated 4-stroke counterpart with the same displacement due to the double firing frequency at the same engine speed. To determine the potential of a downsized two-cylinder 2-stroke poppet valve SI gasoline engine with 0.7 L displacement in place of a naturally aspirated 1.6 L gasoline (NA4SG) engine, one-dimensional models for the 2-stroke gasoline engine with a single turbocharger and a two-stage supercharger-turbocharger boosting system were set up and validated by experimental results.
2016-09-27
Technical Paper
2016-01-8087
Xia Meng
Abstract The output power of a turbocharged diesel engine will decrease and the maximum torque point in the full load torque map will move backwards when the engine is operating at plateau.
2016-06-15
Technical Paper
2016-01-1818
Raimo Kabral, Lin Du, Mats Abom, Magnus Knutsson
Abstract The concept of IC engine downsizing is a well-adapted industry standard, enabling better fuel conversion efficiency and the reduction of tailpipe emissions. This is achieved by utilizing different type of superchargers. As a consequence, the additional charger noise emission, at the IC engine inlet, can become a problem. In order to address such problem, the authors of this work have recently proposed a novel dissipative silencer for effective and robust noise control of the compressor. Essentially, it realizes an optimal flow channel impedance, referred to as the Cremer impedance. This is achieved by means of a straight flow channel with a locally reacting wall consisting of air cavities covered by an acoustic resistance, e.g., a micro-perforated panel (MPP). In this paper, an improved optimization method of this silencer is presented. The classical Cremer impedance model is modified to account for mean flow dependence of the optimal wave number.
2016-04-05
Technical Paper
2016-01-1032
Enrico Mattarelli, Carlo Alberto Rinaldini, Enrico Agostinelli
Abstract The paper reviews the design of the supercharging system for a strongly downsized engine, to be installed on a sport car. Design is supported by cfd-1d engine simulations, using an experimentally calibrated model. The goal of the supercharging system is to deliver the required values of boost pressure at steady operating conditions, and to maintain or improve the full size engine response during acceleration (one of the most critical issues for downsized engines). Two options have been considered: 1) two-stage turbocharging, with two small turbochargers as a high-pressure stage, and one big turbo as low pressure stage (referred to as “TRITURBO”; 2) two-stage supercharging made up of one low pressure stage turbocharger and one electric supercharger (referred to as “E-SUPER”).
2016-04-05
Technical Paper
2016-01-1035
Rasoul Salehi, Jason Martz, Anna Stefanopoulou, Taylor Hansen, Andrew Haughton
Abstract This paper numerically investigates the performance implications of the use of an electric supercharger in a heavy-duty DD13 diesel engine. Two electric supercharger configurations are examined. The first is a high-pressure (HP) configuration where the supercharger is placed after the turbocharger compressor, while the second is a low-pressure (LP) one, where the supercharger is placed before the turbocharger compressor. At steady state, high engine speed operation, the airflows of the HP and LP implementations can vary by as much as 20%. For transient operation under the Federal Test Procedure (FTP) heavy duty diesel (HDD) engine transient drive cycle, supercharging is required only at very low engine speeds to improve airflow and torque. Under the low speed transient conditions, both the LP and HP configurations show similar increases in torque response so that there are 44 fewer engine cycles at the smoke-limit relative to the baseline turbocharged engine.
2016-04-05
Technical Paper
2016-01-1041
Hiep Hoang Tran, Bryn Richard, Kevin Gray, Jonathon M. Hall
Extreme engine downsizing is a modern solution aimed towards the goal of meeting new emissions regulations for internal combustion engines. A higher percentage downsized engine will produce less CO2. By extension, a higher boost level is required to generate high engine torque performance. The transient load step of a higher boost system at low RPM is currently an issue for conventional boosting. Aeristech has developed an electric supercharger to be matched with a conventional turbocharger to create a new type of two stage boosting system and a simpler downsized gasoline engine usable in mainstream vehicle segments. Whereas most electric pressure charging devices are capable of transient output to alleviate turbo lag. The electric supercharger is capable of steady-state air delivery. This makes the electric supercharger a dual-function device, alleviating turbo lag and also supplementing the compressor map of the turbocharger or main boost device.
2016-04-05
Technical Paper
2016-01-0564
Pengfei Lu, Chris Brace, Bo Hu
Abstract The turbo-compounding has been extensively researched as a mean of improving the overall thermal efficiency of the internal combustion engine. Many of the studies aiming to optimize the turbo-compounding system lead to the unified conclusion that this approach is more suitable for the operation under constant high load condition, while it has little effect on improving the fuel economy under low load conditions. Besides, in a traditional series turbo-compounding engine, the increased back pressure unavoidably results in a serious parasitic load to the system by increasing the resistance to the scavenging process. In order to improve this situation, a novel turbo-compounding arrangement has been proposed, in which the turbocharger was replaced by a continuously variable transmission (CVT) coupled supercharger (CVT superchargedr) to supply sufficient air mass flow rate to the engine at lower engine speeds.
2016-04-05
Technical Paper
2016-01-0682
Jason King, Luke Barker, James Turner, John Martin
Abstract SuperGen is a Belt Integrated Starter Generator (B-ISG) combined with a novel electro-mechanical power split transmission system providing variable speed centrifugal supercharger capability, all in one compact package. This paper initially discusses the analysis of SuperGen application to a gasoline SUV in order to examine the BISG power and voltage mild hybrid functionality trade-off versus fuel consumption reduction on drive cycle. A significant engine down speeding was also applied based on the low speed torque enhancement afforded by SuperGen boosting capability, both transiently, and sustainably at steady state engine operation. This has been demonstrated and reported on the well-published Jaguar Land Rover (JLR) Ultraboost project.
2016-04-05
Technical Paper
2016-01-0688
Daniel Uguru-Okorie, Ademola Dare, A. A. Burluka
Abstract Fluctuations in the operational output of spark ignition engines are observed from one engine cycle to the other, when an engine is run at technically identical operating condition. These fluctuations known as cycle-to-cycle variations, when high, adversely affect the performance of an engine. Reduction in cycle-to-cycle variation in engines has been noted by researchers as one of the methods of improving engine efficiency and operational stability. This study investigated the combustion performance characteristics of two fuels: E5 (95% gasoline and 5% ethanol) and ULG98 (unleaded gasoline) in a spark ignition engine, operating at varying inlet pressure conditions and ignition timing. A two-stroke, 80mm bore, spark ignition engine was operated at an engine speed of 750 rpm, inlet pressures of 1.6 and 2.0 bar and spark-timings ranging from 2 to 13 bTDC. A top cylinder head with a centralized spark plug was used in all the experiments.
2016-04-05
Journal Article
2016-01-0663
Michael Bassett, Jonathan Hall, Benjamin Hibberd, Stephen Borman, Simon Reader, Kevin Gray, Bryn Richards
Abstract Gasoline engine downsizing is already established as a proven technology to reduce automotive fleet CO2 emissions by as much as 25 %. Further benefits are possible through more aggressive downsizing, however, the trade-off between the CO2 reduction achieved and vehicle drive-ability limits the level of engine downsizing currently adopted. This paper presents results showing the benefits of adding an eSupercharger to a very heavily downsized engine. Measurements are presented from a 1.2 litre, 3-cylinder, engine fitted with an eSupercharger in addition to a conventional turbocharger. The original MAHLE downsizing engine has been re-configured to enable a specific power output that exceeds 160 kW/litre. Of key importance is a cost effective, efficient and flexible boosting system.
2016-04-05
Technical Paper
2016-01-0293
Jaspreet Singh, Vishnu Agrawal
Abstract The paper expresses an important issue of optimum selection of a supercharger for a given application from the global market in the presence of a variety of superchargers available commercially off the shelf (COTS). Coding scheme suggested is based on developing an attribute based scheme for all superchargers available off the shelf. N-digit coding scheme provides in-depth understanding of all the attributes to be considered by the customers, designers, engineers and engineers of the industry for further improvement. We also aim to create exhaustive database of superchargers along with their attributes. The paper adopts a MADM-TOPSIS (Multiple Attribute Decision Making -Technique for Order of Preference by Similarity to Ideal Solution) technique and graphical methods that are being used widely in different disciplines and are published. The method ensures that the optimum supercharger is closest to the hypothetically best solution and farthest from the worst solution.
2015-11-17
Technical Paper
2015-32-0733
Yasufumi Yoshimoto, Masayuki Yamada, Eiji Kinoshita, Takeshi Otaka
The present study investigated the effect of boost pressure on the operation of a small single cylinder DI diesel engine equipped with a jerk type injection system fueled by different biodiesel fuels. The study employed a Roots blower type supercharger driven by a motor, and the boost pressures were varied from 100 kPa (naturally aspirated condition) to 140 kPa. The experiments used three kinds of biodiesel: rapeseed oil methyl ester (RME), soybean oil methyl ester (SME), and coconut oil methyl ester (CME). Further, a blended fuel with 60% (mass) CME and 40% 1-butanol (represented as CMEB) was also used. The influence of the boost pressure on the engine performance, combustion characteristics, and exhaust emissions with the abovementioned four biofuels were examined and compared with standard JIS No. 2 diesel fuel.
2015-11-17
Technical Paper
2015-32-0729
Hiroyuki Watanabe, Satoaki Ichi, Masahito Saito, Kazuki Arima, Yasushi Ishibashi
1 In the development of motorcycle engines, a strong feeling of power, an element of being fun to ride has continued strong demand. However, demand to meet environmental performance, a conflicting element, has increased dramatically in recent years and a breakthrough technology that achieves both environmental performance and a feeling of power is in demand. Here, the newly developed engine has greatly enhanced feeling of power while clearing stringent environmental restrictions through use of a centrifugal type supercharger. However, there were several problems that had to be resolved with regards to application of a supercharger to a motorcycle engine. In applying a supercharger to a motorcycle, a major problem is the best way to keep the engine size from increasing in size. The engine, which is the heaviest parts on a motorcycle greatly affects motorcycle maneuverability so it must be compact and the mass concentrated.
2015-11-17
Technical Paper
2015-32-0838
Tadamasa Fukuoka, Kazuki Fujimoto, Yuya Hongo, Shinji Kajiwara
Kinki University formula project has been participating in the student Formula SAE of Japan (JSAE) every year for the Competition since the second time. The engine uses ZX-6R made by Kawasaki Heavy Industries for the Competition from the eighth time. “Improvement of limited performance” is inserted in the concept through the development of a power train. Supercharger loading, engine dry sump and engine cooling management were improved. 59.6 kW (80.6 PS) /9000 rpm of maximum output and 70.6 Nm (7.2 kgf m)/8000 rpm of maximum torque were achieved by the supercharger loading. We succeeded in getting 90% of torque band (4000∼10000rpm) by 50% of the number of revolutions in regular use (2000∼12000rpm). Using the dry sump system, hydraulic pressure constantly managed hydraulic pressure at the time of engine operations; the system, where the engine stops at the time of hydraulic pressure fall, was also built.
2015-09-01
Technical Paper
2015-01-1971
Bo Hu, Huayin Tang, Sam Akehurst, Andrew De Freitas, David Burtt, James Shawe
A supercharger system which boosts the engine via a direct drive from the engine crankshaft has been identified as a possible solution to improve low-end torque and transient response for a conventional turbocharged SI engine. However, the engine equipped with a fixed-ratio supercharger is not as fuel-efficient especially at high load and low speed due to the fact that a large portion of the intake mass air flow has to recirculate through a bypass valve causing inevitable mechanical and flow losses. In addition, the fixed drive ratio of the supercharger which is mainly determined by the full-load requirements might not be able to provide sufficient over-boost during a transient. The fact that a clutch may be necessary for high engine speed operation on the fixed-ratio supercharger system is another issue from the perspective of cost and NVH performance.
2015-09-01
Technical Paper
2015-01-1866
Keito Negoro, Yuichi Seki, Mina Nishi, Norimasa Iida, Katsuya Matsuura, Yoshihisa Sato
Nowadays, highly super charging is required corresponded to downsizing concept for improving thermal efficiency in direct-injected spark ignition (DISI) engine. However, highly super charging increases the possibility of super-knock caused by pre-ignition. Recently, in many studies, the reason of pre-ignition has been investigated but the reason why pre-ignition leads such strong knocking called super-knock has not been investigated. In DISI engine, it is estimated that there is more inhomogeneity of equivalence ratio and temperature of air-fuel mixture than it in port injection SI engine. In this study, factors which decide self-ignition timing was reviewed and the influence of inhomogeneity of air-fuel mixture to super-knock was investigated based on numerical calculation.
2015-06-15
Journal Article
2015-01-2307
Neil Figurella, Rick Dehner, Ahmet Selamet, Keith Miazgowicz, Ahsanul Karim, Ray Host
Abstract The effect of aerodynamically induced pre-swirl on the acoustic and performance characteristics of an automotive centrifugal compressor is studied experimentally on a steady-flow turbocharger facility. Accompanying flow separation, broadband noise is generated as the flow rate of the compressor is reduced and the incidence angle of the flow relative to the leading edge of the inducer blades increases. By incorporating an air jet upstream of the inducer, a tangential (swirl) component of velocity is added to the incoming flow, which improves the incidence angle particularly at low to mid-flow rates. Experimental data for a configuration with a swirl jet is then compared to a baseline with no swirl. The induced jet is shown to improve the surge line over the baseline configuration at all rotational speeds examined, while restricting the maximum flow rate. At high flow rates, the swirl jet increases the compressor inlet noise levels over a wide frequency range.
2015-04-14
Journal Article
2015-01-0982
Brandon D. Biller, Philip Wetzel, Pavan Chandras, Sean Keidel
Abstract Several diesel passenger car boosting systems were studied to assess their impact on vehicle performance and fuel economy. A baseline 1.5L diesel engine model with a single VGT turbocharger was obtained through Gamma Technologies' fast running model library. This model was modified to explore multiple two stage boosting systems to represent the anticipated architecture of future engines. A series sequential turbocharged configuration and a series turbocharger-supercharger configuration were evaluated. The torque curves were increased from that of the original engine model to take advantage of the increased performance offered by two stage boosting. The peak cylinder pressure for all models was limited to 180 bar. Drive cycle analysis over the WLTP was performed using these engine architectures, while assessing the sensitivity to various system parameters.
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