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Viewing 1 to 30 of 1366
2013-04-08
Technical Paper
2013-01-1517
Raymond Sutjiono, Prateek Tayal, Keqin Zhou, Peter Meckl
The latest US emission regulations require dramatic reductions in Nitrogen Oxide (NOx) emissions from vehicular diesel engines. Selective Catalytic Reduction (SCR) is the current technology that achieves NOx reductions of up to 90%. It is typically mounted downstream of the existing after-treatment system, i.e., after the Diesel Oxidation Catalyst (DOC) and Diesel Particulate Filter (DPF). Accurate prediction of input NO₂:NO ratio is useful for control of SCR urea injection to reduce NOx output and NH₃ slippage downstream of the SCR catalyst. Most oxidation of NO to NO₂ occurs in the DOC since its main function is to oxidize emission constituents. The DOC thus determines the NO₂:NO ratio as feedgas to the SCR catalyst. The prediction of NO₂:NO ratio varies as the catalyst in the DOC ages or deteriorates due to poisoning. Thus, the DOC prediction model has to take into account the correlation of DOC conversion effectiveness and the aging of the catalyst.
2013-04-08
Technical Paper
2013-01-1518
David W. Wyatt, Hu Li, James Tate
The Carbon Dioxide (CO₂) emission from a EURO 3 diesel van over a real-world driving cycle were investigated utilizing part of the Leeds University - Headingly Ring Road (LU-HR) driving cycle, which comprises both an urban (congested) and extra-urban (high speed) driving section. The vehicle used in this research was a 1.8-liter Ford Connect TDCi diesel van. Emissions were monitored by a Portable Emissions Measurement System (PEMS) incorporating an on-board FTIR (Fourier Transform Infrared) exhaust emission measurement system, a Horiba On Board emissions measuring System (OBS 1300) which measured the exhaust flow rate and air/fuel ratio, and a RaceLogic VBOX II differential GPS system provided geographical position, speed and acceleration data. Route topography is known to have substantial influence on vehicle emission.
2013-04-08
Journal Article
2013-01-1516
Xin Wang, Yunshan Ge, Linxiao Yu
This present paper described an experimental study on the combustion and emission characteristics of a diesel engine at idle at different altitudes. Five altitudes ranging from 550m to up to 4500m were investigated. Combustion parameters including in-cylinder pressure and temperature, heat release, fuel mass burning and so forth, together with emission factors including CO, HC, NOx and PM were tested and analyzed. The result of on-board measurement manifested that in-cylinder pressure descended consistently with the rising of altitude, while both the maximum in-cylinder temperature and exhaust temperature ascended with the altitude. It was found that ignition delay was lengthened at higher altitude, but the combustion duration became shorter. The crank angle towards 90% fuel burnt has hardly changed with the variation of altitude. As for heat release, the difference of slopes observed at different altitudes was quite slight.
2013-04-08
Technical Paper
2013-01-1515
Andreas Hoepfner, Christian A. Roduner
Automotive applications equipped with Diesel engines are subject to stringent legislative requirements in terms of particulate matter (PM) emissions. A Diesel particulate filter (DPF) reduces the tailpipe PM content in the exhaust gas to fulfill the emission thresholds of law's authority. As an emission relevant component, the DPF efficiency must be monitored according to the on-board diagnostic (OBD) regulation. In the US and European market, these OBD regulation limits are becoming more tightened. Currently established methods rely on the analysis of the differential pressure sensor signal across DPF. The measured pressure loss depends on a lot of disturbance variables. Thus, monitoring concepts based on differential pressure become increasingly difficult to comply with future OBD legislation. New developed PM sensors offer the possibility to detect and quantify the particulate emissions in DPF downstream position. This information can be processed in a DPF efficiency OBD monitor.
2013-04-08
Technical Paper
2013-01-1514
Grzegorz Przybyla, Seyed Hadavi, Hu Li, Gordon E. Andrews
The transport sector is one of the major contributors to greenhouse gas emissions. This study investigated three greenhouse gases emitted from road transport using a probe vehicle: CO₂, N₂O and CH₄ emissions as a function temperature. It should be highlighted that methane is a greenhouse gas that similarly to carbon dioxide contributes to global warming and climate change. An oxidation catalyst was used to investigate CO₂, N₂O and CH₄ GHG emissions over a real-world driving cycle that included urban congested traffic and extra-urban driving conditions. The results were determined under hot start conditions, but in congested traffic the catalyst cooled below its light-off temperature and this resulted in considerable N₂O emissions as the oxidation catalyst temperature was in the N₂O formation band. This showed higher N₂O during hot start than for diesel fuel and B100 were compared. The B100 fuel was Fatty Acid Methyl Ester (FAME), derived from waste cooking oil, which was mainly RME.
2013-04-08
Journal Article
2013-01-1513
Yuri Shukhman, Vladimir Baibikov, Abraham Marmur, Mark Veinblat, Leonid Tartakovsky
Many motor vehicles (fire-fighting cars and trucks, helicopters, airplanes, etc.) are used for conflagration extinguishing purposes. It is clear that their engines aspirate air containing combustion inhibitors, which are used for flame suppression, but until now there is no available information about the influence of this fact on engine performance. This paper presents results of an experimental study on the influence of combustion inhibitors, such as Halon 1301 (CF₃Br) and CO₂, contained in the ambient air, on the performance of compression ignition (CI) and spark ignition (SI) engines. Substantial differences in the response of CI and SI engines to the inhibitor presence in the aspirated air are revealed. Starting from relatively small concentrations of CF₃Br, an increase of the CI engine speed and a simultaneous decrease of the brake specific fuel consumption are observed. The speed rise may attain up to 80% of its initial value.
2013-04-08
Technical Paper
2013-01-1512
Arnaud Frobert, Stephane Raux, Yann Creff, Eric Jeudy
Meeting the upcoming NOx emissions standards is a major challenge for the lean-burn engines, thus requiring a highly efficient exhaust gas aftertreatment. Currently, the Selective Catalytic Reduction (SCR) appears to be the most promising technology, especially when operated with two kinds of reductants: ammonia (generally derived from urea) and ethanol. In order to reach high conversion levels while avoiding the overinjection of the reductant, a very accurate model-based control assisted with at least one NOx sensor is required. This study focuses on the sensitivity of NOx sensors to the main nitrogenous species encountered: ammonia, isocyanic acid (HNCO) and hydrogen cyanide (HCN). The cross-sensitivity to ammonia is the only one to be already described in literature and already used in the urea-SCR control systems to limit the risks of ammonia-slip. However, HNCO can also be found downstream of a catalyst during urea-SCR if the urea delivery or the catalyst are deficient.
2013-04-08
Technical Paper
2013-01-1511
Livia Della Ragione, Giovanni Meccariello, Maria Vittoria Prati
In this paper some results relative to tests performed on road with a Fiat Panda Bipower, (CNG and gasoline powered), and a New Panda Twin Air with auto Start & Stop system, are presented. Gaseous emissions are measured with Portable Emission Measurement Systems (PEMS) on two different urban routes, in terms of traffic and slope characteristics during in use experiments. PEMS testing offers an easy and efficient way to evaluate the vehicle emissions over a huge variety of conditions and provides us a direct way to study the in-use emissions of combustion engines, when you want to verify the effect of the traffic and of a particular device on fuel economy and emissions reduction. Moreover now PEMS performances are very comparable to those obtained by standard laboratory instrumentation systems.
2013-04-08
Journal Article
2013-01-1508
Huize Li, Predrag Hrnjak
This paper presents a model analysis of oil effects on the distribution of two phase refrigerant in a parallel flow microchannel evaporator. A microchannel evaporator model developed and presented earlier (SAE paper 2012-01-0321) is enhanced by inclusion of the thermodynamic and transport properties of refrigerant-oil mixture and their impact on boiling heat transfer and pressure drop characteristics. R134a and PAG oil are selected as the working pair. Viscosity effect and OCR effect on refrigerant distribution are investigated using this model, and the results show that 1) High viscosity is detrimental for refrigerant distribution. 2) As OCR increases, distribution becomes worse; but at very high OCR, distribution becomes better. Some initial experimental results show that distribution becomes worse when OCR changes from 0.1% to 3%.
2013-04-08
Journal Article
2013-01-1510
Gilles Delorme
Smart Rear Defog can be defined as an optimized control algorithm that sets the state of a vehicle's rear defog relay based on a logical assessment of vehicle parameters and environmental conditions. The use of the optimized control algorithm will minimize the amount of user interaction needed to operate the rear defogger and it will minimize the amount of heat rejected to the environment which in turn will improve the vehicle's real world fuel economy or electric range. This paper provides a detailed description of the smart rear defog control system as well as evidence to demonstrate its robustness to variances in environmental conditions and vehicle usage compared to the traditional rear defog system commonly used in many vehicles today.
2013-04-08
Technical Paper
2013-01-1507
Mohammad Ali Fayazbakhsh, Majid Bahrami
The Heat Balance Method (HBM) is used for estimating the heating and cooling loads encountered in a vehicle cabin. A load estimation model is proposed as a comprehensive standalone model which uses the cabin geometry and material properties as the inputs. The model is implemented in a computer code applicable to arbitrary driving conditions. Using a lumped-body approach for the cabin, the present model is capable of estimating the thermal loads for the simulation period in real-time. Typical materials and a simplified geometry of a specific hybrid electric vehicle are considered for parametric studies. Two different driving and ambient conditions are simulated to find the contribution and importance of each of the thermal load categories. The Supplemental Federal Test Procedure (SFTP) standard driving cycle is implemented in the simulations for two North American cities and the results are compared.
2013-04-08
Journal Article
2013-01-1506
Roberto Monforte, Massimiliano Mandrile
The subject addressed by this work, currently discussed in Europe following an European Commission inquiry, is the evaluation of the possibility to prevent the MAC (Mobile Air Conditioning) use below 18°C and its benefits in terms of CO2 emissions saving. This strategy, while providing an uncertain fuel consumption saving, has to be faced with basic safety and cabin comfort conditions. The OEMs (Original Equipment Manufacturers) may evaluate to address these concerns by controlling the cabin absolute humidity content. In order to maintain safety it should be acceptable to turn the AC on based on other inputs, such as air distribution modes (defrost or floor/defrost), windshield wiper usage, rear defroster usage, etc. FGA (FIAT Group Automobiles) exploited our proprietary prediction tool to assessing the yearly fuel efficiency that can be achieved in real use by means of the testing results of representative vehicles.
2013-04-08
Journal Article
2013-01-1504
Lothar Seybold, William Hill, Ioannis Lazaridis
The United States Environmental Protection Agency (EPA) as well as the European Commission (EC) are developing test procedures to regulate mobile air conditioning system (MAC) efficiency to reduce greenhouse gas emissions and reduce global warming. In the United States, air conditioning related MAC credits can be earned by implementing an internal heat exchanger (IHX) into a MAC system. By integrating an IHX into a MAC system the, Coefficient of Performance (COP) can be increased at the same time increasing cooling capacity. This improvement in efficiency reduces the energy and/or fuel consumption of the MAC system. This paper will compare various IHX plumbing configurations for a dual evaporator system with R1234yf refrigerant. A MAC system optimized for efficiency as well as evaporator cooling capacity is used to assess these different IHX plumbing configurations.
2013-04-08
Technical Paper
2013-01-1502
Shankar Natarajan, Sathish Kumar S, Ricardo Amaral, Sadek Rahman
Simulation has become an integral part in the design and development of an automotive air-conditioning (AC) system. Simulation is widely used for both system level and component level analyses and are carried out with one-dimensional (1D) and Computational Fluid Dynamics (CFD) tools. This paper describes a 1D approach to model refrigerant loop and vehicle cabin to simulate the soak and cool down analysis. Soak and cool down is one of the important tests that is carried out to test the performance of a heating, ventilation and air-conditioning (HVAC) system of a vehicle. Ability to simulate this cool down cycle is thus very useful. 1D modeling is done for the two-phase flow through the refrigerant loop and air flow across the heat exchangers and cabin with the commercial software AMESim. The model is able to predict refrigerant pressure and temperature inside the loop at different points in the cycle.
2013-04-08
Technical Paper
2013-01-1503
Sathish Kumar S, Shankar Natarajan, Michael V Rinaldi
In an automotive air-conditioning (AC) system, the amount of work done by the compressor is also influenced by the suction line which meters the refrigerant flow. Optimizing the AC suction line routing has thus become an important challenge and the plumbing designers are required to come up with innovative packaging solutions. These solutions are required in the early design stages when prototypes are not yet appropriate. In such scenarios, one-dimensional (1D) simulations shall be employed to compute the pressure drop for faster and economical solution. In this paper, an approach of creating a modeling tool for suction line pressure drop prediction is discussed. Using DFSS approach L12 design iterations are created and simulations are carried out using 1D AMESim software. Prototypes are manufactured and tested on HVAC bench calorimeter. AC suction line pressure drop predicted using the 1D modeling co-related well with the test data and the error is less than 5%.
2013-04-08
Technical Paper
2013-01-1501
Yinhua Zheng
The paper addresses compressor body temperature (crankcase) importance to the vehicle AC system long-term durability. Majority of OEM vehicle test evaluation is to see if AC system can pass compressor discharge temperature and discharge pressure targets. Most OEMs adopt 130°C max compressor discharge temperature and 2350 kpag head pressure as the target. From the field, although some of the compressor failure results from a high compression ratio, and compressor discharge temperature that are caused by the poor front end airflow, etc., high percentage compressor failed systems exhibit not too high compression ratio and compressor discharge temperature, but having the trace of high temperature in the shaft area, gasket area, etc. With introducing more and more variable swash plate compressor applications, OEMs start to see more and more compressor failures that are not related to a high compressor discharge temperature but the trace of high compressor body temperature.
2013-04-08
Journal Article
2013-01-1500
Hanfei Tuo, Predrag Hrnjak
This paper presents experimental study of periodic reverse flow and induced boiling fluctuations in a microchannel evaporator and their impacts on performance of R134a mobile A/C system. Simultaneous flow visualization and pressure measurements revealed that reverse flow due to confined bubble longitudinal expansion caused periodic oscillations of the evaporator inlet pressure and the pressure drop, and their oscillation magnitude and frequency increase with ambient air temperatures because of higher average refrigerant mass flux and heat flux. Three potential impacts of vapor reverse flow reversal on evaporator performance are identified: 1) mild liquid maldistribution; 2) increased the evaporator pressure drop; 3) reduced heat transfer coefficient. Finally, to mitigate vapor reverse flow impacts, revised flash gas bypass (FGBR) method is proposed: vent and bypass backflow vapor trapped in the inlet header.
2013-04-08
Technical Paper
2013-01-1499
Koichi Tabei, Masashi Watanabe, Nobuyuki Doi, Kenjiro Imai, Stefan Young
This paper focuses on the development of the centralized air flow system S-FLOW (Energy Saving Air Flow Control System). The S-FLOW system directs thermal energy to each seating position in the vehicle based on occupancy, thus prioritizing the energy usage based on the particular scenario. The thermal environment in a vehicle's cabin is non-uniform. If the climate control system is used to direct airflow exclusively to any one region of the cabin, without special considerations, comfort may be adversely impacted. To solve this concern, a non-uniform evaluation method was developed to evaluate comfort at each body region of the occupant using the SET* (Standard new effective temperature) method. SET* is a parameter that combines the effects of temperature, airflow velocity, humidity, and other parameters to quantify thermal comfort. Next, a method was established that correlated each body region's SET* value to the occupant's overall thermal comfort.
2013-04-08
Technical Paper
2013-01-1495
Neal Lawrence, Stefan Elbel
Two-phase ejectors have received increased attention in recent years because of their ability to improve the performance of automotive air-conditioning cycles by means of expansion work recovery. Much attention in recent years has been given to how high-pressure fluids, such as carbon dioxide, perform with ejector cycles; high-pressure fluids tend to have higher throttling loss, making them more attractive for expansion work recovery cycles, such as the two-phase ejector cycle. However, low-pressure fluids, such as those commonly used in automotive air-conditioning applications, tend to offer significantly lower work recovery potential. Nonetheless, the limited previous work on low-pressure refrigerants in ejector systems has shown that there is some improvement potential when using these fluids with ejector cycles.
2013-04-08
Journal Article
2013-01-1496
Shenghan Jin, Pega Hrnjak
This paper presents experimental results for refrigerant and lubricant mass distribution in a typical automotive A/C (MAC) system. Experiments were conducted by closing valves located at the inlet and outlet of each component after reaching steady state, isolating the refrigerant and lubricant in each component. Refrigerant mass is recovered in a separate vessel using liquid nitrogen to reduce refrigerant vapor pressure to near vacuum. The overall weight is determined within ±1% after the separation of refrigerant and lubricant. The mass of lubricant is determined by using three different techniques: Remove and Weigh, Mix and Sample, and Flushing. The total mass of lubricant in the system is determined with ±2.5% uncertainty on average. R134a and R1234yf are used with PAG 46 oil as working fluid at different Oil Circulation Ratio (OCR), ranging from 2% to 4%. Experiments are conducted in two standard testing conditions: I35 and L35 (SAE Standard J2765).
2013-04-08
Technical Paper
2013-01-1497
Heejung Jung
Passengers are exposed to roadway pollutants due to entrainment of outside air into the vehicle cabin. Previous works found cabin air-recirculation can reduce pollutant particle concentrations significantly. However simultaneous increase of CO₂ concentrations in the cabin prevented wide use of recirculation mode for such purpose. A mathematical model was developed to predict CO₂ concentrations in vehicle cabin air during air-recirculation mode. The model predicts temporal CO₂ concentration changes as a function of cabin volume, vehicle body leakage, and number of passengers. This model can be used to design and control air-recirculation mode for a variety of vehicle conditions.
2013-04-08
Technical Paper
2013-01-1498
Yang Zou, Predrag Hrnjak
Distribution of R134a in four different vertical headers of microchannel heat exchanger was investigated experimentally. R134a was provided into the header by the microchannel tubes (5 or 10 tubes) in the bottom pass. It left the header through the microchannel tubes (5 or 10 tubes) in the top pass representing the upward flow in the heat pump mode of the reversible systems. The inlet quality was varied from 0.2 to 0.8, and the inlet mass flow rate was from 1.5 to 4.5 kg/h per microchannel tube. Among the test conditions, the aluminum and transparent headers show similar results: refrigerant distribution is better when reducing quality at the same mass flow rate and when increasing mass flow rate at the same quality. Increasing the tubes protrusion and the number of the microchannel tubes usually improve the distribution due to the increase in mass flux. Based on the visualization, churn and separated flow regimes are identified.
2013-04-08
Technical Paper
2013-01-1490
Guangming Wu, Wenku Shi, Zhiyong Chen
Torsional vibration of drive shaft has great influence on the vibration of vehicle. Reasonable phase arrangement of multi-universal coupling can attenuate vibration. In this paper, theoretical model of drive shaft with planar multi-cross universal coupling was established; the optimization scheme of the phase arrangement of multi-cross universal coupling was presented. The results of test validation and simulation show that the optimization scheme is effective and reasonable. The results of test validation and simulation show that the optimization scheme was effective and reasonable and the optimized scheme could solve the abnormal vibration on floor. Arranging phases of universal joints reasonably is very significative for attenuate the torsional vibration of drive shaft and the floor vibration.
2013-04-08
Technical Paper
2013-01-1491
Amit Sandooja
Tolerance stack up is one of the most important exercises of design team to ensure the interchangeability of the components and the sub assemblies in the product having a large product family. Optimized allocation of tolerances between the components in a product helps to reduce the conflicts between the designer and the manufacturer. Automotive gearbox is one of the most important and critical aggregate of any vehicle in which the assembly of gear train performs the function as required. In the gear train, numbers of gears are meshed with each other and transfer the torque on wheels as per the required performance of the vehicle. When the gears are meshed and rotates some noise would generate because of the rolling and sliding action of the gears. This noise is known as “whine noise”. Now days this whine noise is increasingly becoming an important subject for the transmission designers. Gear whine is a total noise that is noticeable to passengers and makes them uncomfortable.
2013-04-08
Journal Article
2013-01-1493
Gursaran D. Mathur
Experimental tests were conducted on a parallel flow condenser with HFO-1234yf as the working fluid on an AC system bench to determine average and local heat transfer coefficients during condensation of HFO-1234yf for mass flow rates that are typically encountered from idle to highway speeds (800 to 3000 rpms). A condenser from MY 2008 medium-sized sedan was used for this investigation. All original OEM parts were used with the alternate refrigerant. Same TXV set-point was used with HFO-1234yf. The magnitude of the measured heat transfer coefficient for condensation was found to be 8~12% lower in comparison to HFC-134a. The magnitudes of the pressure drop during condensation were of the same magnitude as HFC-134a system. The information from this investigation can be used to in the design of condensers for mobile air conditioning systems with HFO-1234yf as the working fluid.
2013-04-08
Technical Paper
2013-01-1481
Mihael Cipek, Mirko Čorić, Branimir Škugor, Josip Kasać, Joško Deur
A dynamic programming-based algorithm is developed and used for off-line optimization of range extended electric vehicle power train control variables over standardized certification driving cycles. The aim is to minimize the fuel consumption subject to battery state-of-charge constraints and physical limits of different power train variables. The control variables to be optimized include engine torque and electric machine speed, as well as a variable that selects the power train operating mode. The optimization results are presented for four characteristic certification driving cycles and characteristic vehicle operating regimes including electric driving during charge depleting mode, hybrid driving during charge sustaining mode, and combined/blended regime.
2013-04-08
Technical Paper
2013-01-1494
Michael L. Grady, Heejung Jung, Yong chul Kim, June Kyu Park, Bock Cheol Lee
A fractional recirculation of cabin air was proposed and studied to improve cabin air quality by reducing cabin particle concentrations. Vehicle tests were run with differing number of passengers (1, 2, 3, and 4), four fan speed settings and at 20, 40, and 70 mph. A manual control was installed for the recirculation flap door so different ratios of fresh air to recirculated air could be used. Full recirculation is the most efficient setting in terms of thermal management and particle concentration reduction, but this causes elevated CO₂ levels in the cabin. The study demonstrated cabin CO₂ concentrations could be controlled below a target level of 2000 ppm at various driving conditions and fan speeds with more than 85% of recirculation. The proposed fractional air recirculation method is a simple yet innovative way of improving cabin air quality. Some energy saving is also expected, especially with the air conditioning system.
2013-04-08
Technical Paper
2013-01-1482
Hanyu Chen, Chengji Zuo
Based on the concept of dynamic servo, an electromagnetic coupling hybrid electric vehicle is developed. The system structure, working principle and control strategy of the vehicle are analyzed respectively. The simulation model of the vehicle is built using Matlab/Simulink software, and the output torque of ICE, EM and DRM is simulated in UDDS driving cycle. The simulation and test results show that the output torque can meet the requirements of driving cycle, and the efficiency of EM is always in high efficiency area.
2013-04-08
Journal Article
2013-01-1483
Zhe Li, Jaspal Sandhu
Torsional vibration dampers are used in automatic and manual transmissions to provide passenger comfort and reduce damage to transmission & driveline components from engine torsionals. This paper will introduce a systematic method to model a torque converter (TC) arc spring damper system using Simdrive software. Arc spring design parameters, dynamometer (dyno) setup, and complete powertrain/driveline system modeling and simulation are presented. Through arc spring dynamometer setup subsystem modeling, the static and dynamic stiffness and hysteresis under different engine loads and engine speeds can be obtained. The arc spring subsystem model can be embedded into a complete powertrain/driveline model from engine to wheels. Such a model can be used to perform the torsional analysis and get the torsional response at any location within the powertrain/driveline system. The new methodology enables evaluation of the TC damper design changes to meet the requirements.
2013-04-08
Journal Article
2013-01-1488
Guangming Wu, Wenku Shi, Zhiyong Chen
The performance parameters of torsional vibration damper, including stiffness and damping, have great influence on the torsional vibration of automobile driveline. At present, the research on torsional vibration damper mainly concentrates on the torsional stiffness, but rarely on the torsional damping characteristics. This paper systematically studied the effect of torsional stiffness and damping on torsional vibration of automobile driveline under uniform speed conditions, accelerated and decelerated conditions, idling conditions and resonance conditions. The requirements on stiffness and damping of various operating conditions were summarized. The effect and requirements researched were useful to performance match design of torsional vibration damper.
Viewing 1 to 30 of 1366

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