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Viewing 91 to 120 of 43643
2017-03-28
Technical Paper
2017-01-1682
Matthew von der Lippe, Mark Waterbury, Walter J. Ortmann, Bernard Nefcy, Scott Thompson
Abstract The FMEA and DV&PV process of developing automotive products requires identifying and repeatedly testing critical vehicle attributes and their response to noise factors that may impair vehicle function. Ford has developed a new automated scripting tool to streamline in-vehicle robustness testing and produce more accurate and repeatable results. Similar noise factors identified during the FMEA process are grouped together, condensed, and scripts are developed to simulate these noise factors using calibration parameters and vehicle controls. The automated testing tool uses the API of a calibration software tool and a graphical scripting interface to consistently simulate driver inputs with greater precision than a human calibrator and enable more sophisticated controls, which would have previously required experimental software builds.
2017-03-28
Technical Paper
2017-01-0943
Cory S. Hendrickson, Devesh Upadhyay, Michiel Van Nieuwstadt
Over the past decade urea-based selective catalytic reduction (SCR) has become a leading aftertreatment solution to meet increasingly stringent Nitrogen oxide (NOx) emissions requirements in diesel powertrains. A common trend seen in modern SCR systems is the use of "split-brick" configurations where two SCR catalysts are placed in thermally distinct regions of the aftertreatment. One catalyst is close-coupled to the engine for fast light-off and another catalyst is positioned under-floor to improve performance at high space velocities. Typically, a single injector is located upstream of the first catalyst to provide the reductant necessary for efficient NOx reduction. This paper explores the potential benefit, in terms of improved NOx reduction and control of NH3 slip, of having independently actuated injectors in front of each catalyst.
2017-03-28
Technical Paper
2017-01-0944
Ryuji Ando, Takashi Hihara, Yasuyuki Banno, Makoto Nagata, Tomoaki Ishitsuka, Nobuyuki Matsubayashi, Toshihisa Tomie
Cu-SSZ-13 is widely used as a material for Cu-SCR catalyst. The Cu-SCR catalyst shows high NOx performance and has high thermal durability but it deteriorates in NOx performance when it suffers Sulfur poisoning. Authors investigated the detailed mechanism how the catalyst is poisoned by Sulfur, and also studied the optimum de-Sulfation conditions. As to the Sulfur adsorption site in the Cu-zeolite, we performed DFT calculation to know the site candidate and we performed precise characterization. As characterization techniques of Sulfur poisoning of the catalyst, we mainly used EUPS (Extreme Ultraviolet Photoelectron Spectroscopy) and DRIFTS. By those techniques, we found out that Sulfur adsorbs on ion-exchanged Cu site and Al site in the Zeolite structure. Especially the Cu site is an active site of the catalyst and thus the Cu-SCR catalyst deteriorated by the Sulfur poisoning.
2017-03-28
Technical Paper
2017-01-0606
Ashley Wiese, Anna Stefanopoulou, Julia Buckland, Amey Y. Karnik
Low-Pressure Exhaust Gas Recirculation (LP-EGR) has been shown to be an effective means of improving fuel economy and suppressing knock in downsized, boosted, spark ignition engines. LP-EGR is particularly beneficial at low-speed, high-load conditions, but can lead to combustion instability at lower loads. The transport delays inherent in LP-EGR systems slow the reduction of intake manifold EGR concentrations during tip-out events, which may lead to excessive EGR concentrations at low load. This paper explores leveraging Variable Valve Timing (VVT) as a means of improving the rate of reduction of intake manifold EGR concentration prior to tip-out. At higher boost levels, high valve overlap may result in intake manifold gas passing directly to the exhaust manifold. This short-circuiting behaviour could potentially improve EGR evacuation rates.
2017-03-28
Technical Paper
2017-01-0658
Achint Rohit, Sridev Satpathy, Jeongyong Choi, John Hoard, Gopichandra Surnilla, Mohannad Hakeem
Diminishing petroleum reserves and increasingly stringent emission targets globally, have forced the automotive industry to move towards downsized boosted direct injection engines. Boosted engines operate at high mean effective pressure (MEP) resulting in high in-cylinder pressure and thermal loading which could give rise to abnormal combustion events like knock and pre-ignition. These events could lead to damage of engine components; therefore the compression ratio and boost pressure are restricted, which in-turn limits the engine efficiency and power. To mitigate conditions where the engine is prone to knocking, the engine control system uses spark retard or mixture enrichment, which decrease indicated work and increase specific fuel consumption. Several researchers have advocated water injection as an approach to replace existing knock mitigating techniques. The first studies on its potential for knock inhibition can be traced back to early 1930's studies by Ricardo.
2017-03-28
Technical Paper
2017-01-0664
Mohd Asif, Karl Giles, Andrew Lewis, Sam Akehurst, Niall Turner
Engine downsizing, the practice of reducing engine displacement whilst maintaining key drivability characteristics, is a well-established method by which automotive manufacturers improve the fuel economy of their products. This improvement is achieved primarily via reduced pumping and friction losses within the engine, as well as by reducing overall vehicle weight. However, the higher BMEP requirement of downsized engines results in increased peak pressures and temperatures within the cylinder. Subsequently, there is an increased tendency for downsized engines to experience damaging forms of abnormal combustion such as pre-ignition and knock. The causes of knock are well understood but it is important to be able to relate these causes to the effects of controllable engine parameters. This study attempts to quantify the effects of several key engine parameters on the knock behavior of a 60% downsized, DISI engine running at approximately 23 bar BMEP.
2017-03-28
Technical Paper
2017-01-0917
Go Hayashita, Motoki Ohtani, Keiichiro Aoki, Shuntaro Okazaki
Trying to prevent global warming and air pollution, Toyota has led the world in the field of after treatment technologies including the three-way catalyst (TWC) system with oxygen sensor. In this study, a new emission control system for Toyota New Global Architecture (TNGA) Engine which brings lower fuel consumption and higher performance for creating ever-better cars is reported. The new system was adopted the exhaust cooling system and small capacity TWC. These can achieve a balance between heating TWC for early activation and cooling TWC for protection. As a result, regardless of the platform or the unit type of the vehicle, it is possible to unify the catalyst temperature which is a key parameter in the exhaust gas purification. In order to reduce emission also with the small capacity TWC, it is necessary to a high accuracy air-fuel ratio (A/F) control.
2017-03-28
Technical Paper
2017-01-1002
Daisuke Tanaka, Ryo Uchida, Toru Noda, Andreas Kolbeck, Sebastian Henkel, Yannis Hardalupas, Alexander Taylor, Allen Aradi
Reducing engine-out particulates is one of the main issues of direct injection gasoline engines and further efforts are still needed to comply with near-future emission regulations. However, engine-out particulate emission characteristics strongly depend on fuel properties associated with the combustion design and/or calibration, due to the complicated mechanisms of particulate formation, including both physical and chemical processes. For these reasons, the purpose of this work was to gain a fundamental understanding of which fuel property parameters are responsible for particulate emission characteristics, associated with key intermediate behavior in the engine cylinder. Accordingly, engine tests were carried out using various fuels having different volatility and chemical compositions under different coolant temperature conditions. In addition, a fundamental spray and film visualization analysis was also conducted using a constant volume vessel.
2017-03-28
Technical Paper
2017-01-1000
Jong Lee, Yu Zhang, Tom Tzanetakis, Michael Traver, Melanie Moses-DeBusk, John Storey, William Partridge, Michael Lance
With higher volatility and longer ignition delay characteristics than typical diesel fuel, low cetane naphtha fuel has been shown to promote partially premixed combustion and produce lower soot for improved fuel economy. In this study, emission performance of low cetane, low octane naphtha (CN 35, RON 60) as a drop-in fuel was examined on a MY13 Cummins ISX15 6-cylinder heavy-duty on-highway truck engine and aftertreatment system. Using the production hardware and development calibrations, both the engine-out and tailpipe emissions of naphtha and ultra-low sulfur diesel (ULSD) fuels were examined during the EPA’s heavy-duty emission testing cycles. Without any modification to the calibrations, the tailpipe emissions were comparable when using naphtha or ULSD on the heavy duty Federal Test Procedure (FTP) and ramped modal cycle (RMC) test cycles.
2017-03-28
Technical Paper
2017-01-0759
Rasmus Pettinen, Ossi Kaario, Martti Larmi
Unstable oil markets combined with the alarming statistics of continuously growing emission problems causes anxiety among many nations. The greatest dilemma lies in the answer about how to rationally overcome the dependency of fossil based energy sources. The truth seems to be found on utilizing renewable energy generating low emissions. Methane is suggested as one of the worthwhile solutions for substituting crude-oil based fuels. Methane as a fuel combined with modern engine technology seems to open possibilities solving the above mentioned problems. Charge air mixed methane combined with a compression ignition engine utilizing a small diesel pilot injection seems to form a profitable compromise between good engine efficiency and low emission outcome. Problems concerning dual-fuel technology profitableness seems to be related to fully control the combustion in relation to lean conditions.
2017-03-28
Technical Paper
2017-01-0633
Kurt Stuart, Terry Yan, James Mathias
In the interest of improving the efficiency of the internal combustion engine, many alternatives to the traditional 4-stroke engine have been proposed. One promising alternative is the 5-stroke engine, which adds an additional expansion stroke to the traditional 4-stroke engine. By adding an additional expansion stroke, the combustion gas can be further expanded with increased work output for the same heat input. The extra expansion stroke, i.e. the 5th stroke, is accomplished in a separate cylinder operating on a 2 stroke cycle. This can be readily accomplished by adding one expansion cylinder with two combustion cylinders operating 360 degree off-phase, creating an engine with 3 cylinders. Previous works have investigated the interactions of the engines operating points and design parameters. Few have, however, included in-cylinder heat transfer and mass lost due to blow-by, which can have a significant effect on the thermodynamic performance of such an engine.
2017-03-28
Technical Paper
2017-01-0964
Jakob Heide, Mikael Karlsson, Mireia Altimira
Selective Catalytic Reduction (SCR) of NOx through injection of Urea-Water-Solution (UWS) into the hot exhaust gas stream is an effective and extensively used strategy in internal combustion engines. Even though actual SCR systems have 95-96% de-NOx efficiency over test cycles, real driving emissions of NOx are much higher, hence proving that there is room for improvement. The efficiency of the NOx conversion is highly dependent on the size of UWS droplets and their spatial distribution. These factors are, in turn, mainly determined by the spray characteristics and its interaction with the exhaust gas flow. The main purpose of this study is to numerically investigate the sensitivity to the modelling framework of the evaporation and mixing of the spray upstream of the catalyst. The dynamics of discrete droplets is handled through the Lagrangian Particle Tracking framework, with models that account for droplet breakup and coalescence, turbulence effects, and water evaporation.
2017-03-28
Technical Paper
2017-01-0965
Lorenzo Nocivelli, Gianluca Montenegro, Angelo Onorati, Francesco Curto, Panayotis Dimopoulos Eggenschwiler, Yujun Liao, Alexander Vogel
The application of liquid aqueous Urea Solution (AUS) as reductant in SCR exhaust after-treatment systems is now a commonly accepted industry standard. Unfortunately less acceptable are the associated difficulties caused by incomplete decomposition of the liquid resulting in solid deposits accumulation in the downstream exhaust pipe dosing components and the SCR itself. The correct prediction of the spray pattern and therefore the spray impact on the walls is a key feature for the system optimization. A mechanical patternator, designed on the basis of CFD performance assessment involving a Lagrangian representation of the dispersed liquid fully coupled with a 3D Eulerian description of the carrier phase, has been built and used to measure the spray mass distribution.
2017-03-28
Technical Paper
2017-01-1022
Kazuhiro Ogino, Yoshinori Yakabe, Keisuke Chujo
The new 3.5L V6 Direct injection gasoline engine VQ35DD is developed for midsize premium SUV. This engine is developed as the latest descendant of the VQ engine family with the latest technologies. Primarily it is aimed to enhance driving performance combined with good environmental performance. Together with these torque/power increase and FE / emission improvements, simultaneous realization of both throttle response and smoothness are also prioritized. To achieve these features, direct injection system, high response motor driven intake CVTC, individual spark timing, mirror bore spray coating on cylinder block and various friction reduction technologies such as variable displacement oil pump are applied. Thus maximum engine power and torque are increased by 8 to 10%. Minimum BSFC is improved by 6% and wider spread of lower BSFC area considering CVT application. This paper describes overview of the engine, details of new technologies, and achievements of the aimed performance.
2017-03-28
Technical Paper
2017-01-1023
Yaqun Jiang, C. Hsieh, Georg Festag, Masood Ahmed, William Jiang
Large axial displacement at the edge of a flywheel caused a clutch fail to disengage in high-speed rotation. To find out the root cause and solve the problem, a numerical procedure is proposed to investigate the vibration source and to understand dynamic behavior of the crank-train system. A simulation of the whole engine system including block, crankshaft, piston and connecting rod was performed with AVL/Excite. The baseline model was correlated with measurement. A comprehensive study was conducted for a set of flywheel and crankshaft models with different materials and unbalance masses. The contribution to flywheel wobbling of each vibration order was carefully investigated, and an optimal design was presented.
2017-03-28
Technical Paper
2017-01-1026
Richard Morton, Romain Riviere, Stephen Geyer
A study of the crank and geartrain dynamics of a 2-stroke opposed piston diesel engine design uncovered a disconnect between the thermodynamic process and its conversion to mechanical work. The classic 2-stroke opposed piston design phases the intake piston to lag the exhaust piston in order to achieve favorable gas exchange, overcoming the disadvantage of piston-controlled ports. One result of this is that significantly more of the engine torque is delivered by the leading crank than from the trailing one. This paper will examine why this torque difference occurs, and show that it is not simply a proportioning of the available thermodynamic work, but a result of a fundamental mechanical loss mechanism that limits the achievable brake efficiency of this engine architecture. By providing an understanding of this loss mechanism, this analysis will provide a basis for developing effective design solutions to overcome it.
2017-03-28
Technical Paper
2017-01-1056
Rong Guo, Xiao-Kang Wei, Jun Gao
Commercial demands of comfort and stringent fuel economy have encouraged manufacturers to accommodate advanced technologies such as the Variable Displacement Engine (VDE), downsizing and so on in the new automotive models. Particularly, Active control engine mounts (ACMs) notably contribute to ensuring superior effectiveness in vibration suppression. This paper incorporates a PID controller into the active control engine mount system for inhabiting the transmitted force to the body. Furthermore, integrated time absolute error (ITAE) of the transmitted force is introduced to serve as the control goal for searching better PID parameters. Then the particle swarm optimization (PSO) algorithm is adopted for the first time to optimize the PID parameters in the ACM system. In the end, simulation results are presented for searching optimal PID parameters and validating the performance of the optimized PID control method.
2017-03-28
Technical Paper
2017-01-1235
Baoming Ge, Lihua Chen, Shuitao Yang
Electrified vehicles (xEV) require high torque/acceleration ability and wide speed range. To meet both of them, the traction machines have to be oversized, which results in large volume and weight, high cost, and low efficiency. In practical applications, high speed motors combining with gear box achieve tradeoff between torque and speed capacity, because the increased motor speed can reduce the motor volume at the same power rating and the gear box is employed to increase torque. In fact, electric machine can achieve “electrical gear” rather than using “mechanical gear”, so electric machines integrate “gear” and “motor” together, as a result that “mechanical gear” can be minimized. “Electrical gear” of electric machine is performed by pole-changing. In the past, pole-changing employs mechanical contactor, the windings are de-energized prior to pole changing and the stator winding needs to be reconfigurable using contactors, which will produce discontinuous torques.
2017-03-28
Technical Paper
2017-01-1227
Ali Najmabadi, Michael Kress, Brett Dryer, Ahmad Arshan Khan
This paper studies different switching schemes for loss reduction in a traction motor drive. The system under examination is composed of a battery, a 2 level Voltage Source Inverter, and an Interior Permanent Magnet motor. Discontinuous PWM (DPWM) control strategy is widely used in this type of motor drive for the reduction of losses. In some publications, the effect of the DPWM modulation scheme is compared to the reduction of the switching frequency which can also cause a reduction in switching losses of the inverter. Extensive studies have examined the effect of variation of the switching frequency on the motor and inverter losses. However, the effect of applying both switching schemes simultaneously has not been explored. This paper will use a system that is operated at a fixed switching frequency as the baseline. Afterwards, three different switching schemes will be studied and compared to the baseline.
2017-03-28
Technical Paper
2017-01-0672
Yanyu Wang, Jiongxun Zhang, Paul Dice, Xin Wang, Mahdi Shahbakhti, Jeffrey Naber, Michael Czekala, Qiuping Qu, Garlan Huberts
Abstract The effect of flow direction towards the spark plug electrodes on ignition parameters is analyzed using an innovative spark aerodynamics fixture that enables adjustment of the spark plug gap orientation and plug axis tilt angle with respect to the incoming flow. The ignition was supplied by a long discharge high energy 110 mJ coil. The flow was supplied by compressed air and the spark was discharged into the flow at varying positions relative to the flow. The secondary ignition voltage and current were measured using a high speed (10MHz) data acquisition system, and the ignition-related metrics were calculated accordingly. Six different electrode designs were tested. These designs feature different positions of the electrode gap with respect to the flow and different shapes of the ground electrodes. The resulting ignition metrics were compared with respect to the spark plug ground strap orientation and plug axis tilt angle about the flow direction.
2017-03-28
Technical Paper
2017-01-0669
Matthieu LEGUILLE, Frederic Ravet, Jerome Le Moine, Eric Pomraning, Keith Richards, P. K. Senecal
Abstract The current trend of downsizing used in gasoline engines, while reducing fuel consumption and CO2 emissions, imposes severe thermal loads inside the combustion chamber. These critical thermodynamic conditions lead to the possible auto-ignition (AI) of fresh gases hot-spots around Top-Dead-Center (TDC). At this very moment where the surface to volume ratio is high, wall heat transfer influences the temperature field inside the combustion chamber. The use of a realistic wall temperature distribution becomes important in the case of a downsized engine where fresh gases hot spots found near high temperature walls can initiate auto-ignition. This paper presents a comprehensive numerical methodology for an accurately prediction of thermodynamic conditions inside the combustion chamber based on Conjugate Heat Transfer (CHT).
2017-03-28
Technical Paper
2017-01-0666
Zhenbiao Zhou, Yi Yang, Michael Brear, Joshua Lacey, Thomas G. Leone, James E. Anderson, Michael H. Shelby
Abstract Combustion in modern spark-ignition (SI) engines is increasingly knock-limited with the wide adoption of downsizing and turbocharging technologies. Fuel autoignition conditions are different in these engines compared to the standard Research Octane Number (RON) and Motor Octane Numbers (MON) tests. The Octane Index, OI = RON - K(RON-MON), has been proposed as a means to characterize the actual fuel anti-knock performance in modern engines. The K-factor, by definition equal to 0 and 1 for the RON and MON tests respectively, is intended to characterize the deviation of modern engine operation from these standard octane tests. Accurate knowledge of K is of central importance to the OI model; however, a single method for determining K has not been well accepted in the literature.
2017-03-28
Technical Paper
2017-01-0665
Hassan vafamehr, Alasdair Cairns, Mohammadmohsen Moslemin Koupaie
Abstract The experimental work was concerned with improving understanding of the competing effects of the latent heat of vaporization and auto-ignition delay times of different ethanol blended fuels during heaving knocking combustion. The unique single cylinder SI engine employed included full bore overhead optical access capable of withstanding unusually high in-cylinder pressures. Heavy knock was deliberately induced under moderate loads using inlet air heating and a primary reference fuel blend of reduced octane rating. High-speed chemiluminescence imaging and simultaneous in-cylinder pressure data measurement were used to evaluate the combustion events. Under normal operation the engine was operated under port fuel injection with a stoichiometric air-fuel mixture. Multiple centered auto-ignition events were regularly observed, with knock intensities of up to ~40bar. Additional excess fuel of varied blend was then introduced directly into the end-gas in short transient bursts.
2017-03-28
Technical Paper
2017-01-0668
Arsham J. Shahlari, Jaal Ghandhi
Abstract Highly time resolved measurements of cylinder pressure acquired simultaneously from three transducers were used to investigate the nature of knocking combustion and to identify biases that the pressure measurements induce. It was shown by investigating the magnitude squared coherence (MSC) between the transducer signals that frequency content above approximately 40 kHz does not originate from a common source, i.e., it originates from noise sources. The major source of noise at higher frequency is the natural frequency of the transducer that is excited by the impulsive knock event; even if the natural frequency is above the sampling frequency it can affect the measurements by aliasing. The MSC analysis suggests that 40 kHz is the appropriate cutoff frequency for low-pass filtering the pressure signal. Knowing this, one can isolate the knock event from noise more accurately.
2017-03-28
Technical Paper
2017-01-0667
George Lavoie, Robert Middleton, Jason Martz, Satheesh Makkapati, Eric Curtis
Abstract This study investigates the use of a characteristic reaction time as a possible method to speed up automotive knock calculations. In an earlier study of HCCI combustion it was found that for ignition at TDC, the ignition delay time at TDC conditions was required to be approximately 10 crank angle degrees (CAD), regardless of engine speed. In this study the analysis has been applied to knock in SI engines over a wide range of engine operating conditions including boosted operation and retarded combustion phasing, typical of high load operation of turbocharged engines. Representative pressure curves were used as input to a detailed kinetics calculation for a gasoline surrogate fuel mechanism with 312 species. The same detailed mechanism was used to compile a data set with traditional constant volume ignition delays evaluated at the peak pressure conditions in the end gas assuming adiabatic compression.
2017-03-28
Technical Paper
2017-01-1004
Jan Czerwinski, Pierre Comte, Norbert Heeb, Andreas Mayer, Volker Hensel
Abstract In the present paper some results of investigations of nanoparticles from five DI gasoline cars are represented. The measurements were performed at vehicle tailpipe and in CVS-tunnel. Moreover, five variants of “vehicle - GPF” were investigated. These results originate from the project GasOMeP (Gasoline Organic & Metal Particulates), which focused on metal-nanoparticles (including sub 20nm) from gasoline cars with different engine technologies. The PN-emission level of the investigated GDI cars in WLTC without GPF is in the same range of magnitude very near to the actual limit value of 6.0 × 1012 #/km. With the GPF’s with better filtration quality, it is possible to lower the emissions below the future limit value of 6.0 × 1011 #/km. There is no visible nuclei mode and the ultrafine particle concentrations below 10mm are insignificant. Some of the vehicles show at constant speed operation a periodical fluctuation of the NP-emissions, as an effect of the electronic control.
2017-03-28
Technical Paper
2017-01-1003
Ye Liu, Gang Lv, Chenyang Fan, Na Li, Xiaowei Wang
Abstract The evolution of surface functional groups (SFGs) and the graphitization degree of soot generated in premixed methane flames are studied and the correlation between them is discussed. Test soot samples were obtained from an optimized thermophoretic sampling system and probe sampling system. The SFGs of soot were determined by Fourier transform infrared spectroscopy (FT-IR) and X-ray photoelectron spectroscopy (XPS) after removing the soluble impurities from the soot samples, while the graphitization degree of soot was characterized by Raman spectrum and electron energy loss spectroscopy (EELS). The results reveal that the number of aliphatic C-H groups and C=O groups shows an initial increase and then decrease in the sooting history. The large amount of aliphatic C-H groups and small amount of aromatic C-H groups in the early stage of the soot mass growth process indicate that aliphatic C-H groups make a major contribution to the early stage of soot mass growth.
2017-03-28
Technical Paper
2017-01-0937
David Culbertson, James Pradun, Magdi Khair, Jeff Diestelmeier
Abstract Tightening regulations throughout the world demand a reduction in fuel consumption and NOX emission levels, creating an increasing need for additional heat for SCR aftertreatment. A durable and low cost heating system is needed for vehicles with hybrid or 24Vdc electricity. Recent development efforts have resulted in much smaller and lower cost heating systems for electrical systems ranging from 400 to 24Vdc. Test results demonstrate the feasibility of reducing the size of the heater and the relationship of heater power to the amount of time required to heat the exhaust. Intelligent solid state switching enables the heater to be smaller without compromising durability.
2017-03-28
Technical Paper
2017-01-1064
Mustafa Yıldırım
Abstract Engine design is crucial in terms of NVH. It is the sources of vibration for a vehicle. Nowadays engine tends to being smaller and less stiff and more powerful according to predecessor. Small engines with high power is inherently generates extreme force and vibrations and accordingly generates more noise. Thus engine structure and also engine main components should be designed to prevent this vibration. There are two main sources: One of them is combustion and other is inertia loads. Due to this sources engine structure can cause severe vibration and accordingly this can cause noise via transmitting it into vehicle with both structure and airborne. This paper focused on to reduce engine vibration level with changing the combustion inputs such as cylinder pressure parameters and inertia parameters like piston mass, conrod length and balancing parameters. Design of experiment is used to obtain most robust case in terms of NVH.
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.
Viewing 91 to 120 of 43643