Display:

Results

Viewing 121 to 150 of 9785
Technical Paper
2014-04-01
Kambiz Jahani, Sajjad Beigmoradi
Abstract Adequate visibility through the automobile windscreen is a critical aspect of driving, most often at very low temperatures when ice tends to be formed on the windscreen. The geometry of the existing defroster system needs to be improved in the vehicles, with the main aim of substantial increase in air mass flow reaching the windscreen through defroster nozzles and appropriate velocity distribution over the windscreen, while respecting all packaging constraints. The reason of this study is to investigate the windscreen deicing behavior of a vehicle by means of Computational Fluid Dynamics (CFD) with the main concern of improving deicing process by design an appropriate defroster. Two different defrosters with completely different geometry are considered for this purpose. A detailed full interior model of an existing vehicle is created via CAE tools. A transient simulation is performed and results are extracted to show how a proper design of the defroster will lead to considerable improve in deicing process.
Technical Paper
2014-04-01
Neal Lawrence, Stefan Elbel
Abstract Two-phase ejectors are devices capable of recovering the expansion power that is lost by the throttling process in air conditioning cycles, resulting in improved system performance. High-pressure fluids such as CO2 have received the majority of attention in two-phase ejector studies in recent years due to the fluid's high throttling loss and high potential for improvement. However, low-pressure working fluids such as R134a, commonly used in automotive applications, have received considerably less attention owing to their lower recovery potential. While the two fluids have very different properties, both offer the potential for noticeable COP improvement with ejector cycles. Thus, understanding the operation and performance of ejectors with both fluids can be important to the design of ejector air conditioning cycles. This paper compares available experimental data for the performance of two-phase ejectors using CO2 and R134a. CO2 ejectors are capable of recovering a greater amount of power than R134a due to CO2's larger throttling loss as well as the ability of CO2 ejectors to recover a larger portion of the available power.
Technical Paper
2014-04-01
Andrew P. Roberts, Richard Brooks, Philip Shipway, Robert Gilchrist, Ian Pegg
Abstract The thermal efficiency of an internal combustion engine at steady state temperatures is typically in the region of 25-35%[1]. In a cold start situation, this reduces to be between 10% and 20% [2]. A significant contributor to the reduced efficiency is poor performance by the engine lubricant. Sub optimal viscosity resulting from cold temperatures leads to poor lubrication and a subsequent increase in friction and fuel consumption. Typically, the engine lubricant takes approximately twenty minutes [3] to reach steady state temperatures. Therefore, if the lubricant can reach its steady state operating temperature sooner, the engine's thermal efficiency will be improved. It is hypothesised that, by decoupling the lubricant from the thermal mass of the surrounding engine architecture, it is possible to reduce the thermal energy loss from the lubricant to the surrounding metal structure in the initial stages of warm-up. Using a bespoke oil flow rig described in the methodology section of this paper, it has been demonstrated that the addition of a 2 mm thick nylon tube, increases the maximum temperature differential between the lubricant and surrounding metal by 145% and reduces the energy losses from the gallery by 50%.
Technical Paper
2014-04-01
Jason Aaron Lustbader, Cory Kreutzer, Matthew A. Jeffers, Steven Adelman, Skip Yeakel, Philip Brontz, Kurt Olson, James Ohlinger
Abstract Cab climate conditioning is one of the primary reasons for operating the main engine in a long-haul truck during driver rest periods. In the United States, sleeper cab trucks use approximately 667 million gallons of fuel annually for rest period idling. The U.S. Department of Energy's National Renewable Energy Laboratory's (NREL) CoolCab Project works closely with industry to design efficient thermal management systems for long-haul trucks that minimize engine idling and fuel use while maintaining occupant comfort. Heat transfer to the vehicle interior from opaque exterior surfaces is one of the major heat pathways that contribute to air conditioning loads during long-haul truck daytime rest period idling. To quantify the impact of paint color and the opportunity for advanced paints, NREL collaborated with Volvo Group North America, PPG Industries, and Dometic Environmental Corporation. Initial screening simulations using CoolCalc, NREL's rapid HVAC load estimation tool, showed promising air-conditioning load reductions due to paint color selection.
Technical Paper
2014-04-01
Can Yang, Hui Xie, Shengkai Zhou
Abstract The RCS (Rankine cycle system) used to recover the exhaust gas energy from internal combustion engines has been regarded as one of the most promising ways to achieve higher efficiency. However, it is a big challenge to keep the RCS still in good performance under variable driving cycle. This paper aims at revealing the reasons resulting in the low efficiency under driving cycle, comparing to that under steady-state condition. The dynamic operating process of the RCS under driving cycle is analyzed, and then the RCS applied on an 11.6L heavy duty diesel engine is modeled. Based on that, the dynamic performance of the RCS under an actual driving cycle is discussed. The results indicate that the average efficiency under a piece of Tianjin bus driving cycle is as low as 3.63%, which is less than half of that (7.77%) under the rated point (1300rpm and 50%load). The reasons leading to the low efficiency under driving cycle is interpreted from three aspects. Firstly, effects of the optimizing criterions are studied.
Technical Paper
2014-04-01
Takatoshi Furukawa, Masaaki Nakamura, Koichi Machida, Kiyohiro Shimokawa
Abstract In heavy duty (HD) trucks cruising on expressway, about 60% of input fuel energy is wasted as losses. So it is important to recover them to improve fuel economy of them. As a waste heat recovery system, a Rankine cycle generating system was selected. And this paper mainly reports it. In this study, engine coolant was determined as main heat source, which collected energies of an engine cooling, an EGR gas and an exhaust gas, for collecting stable energy as much as possible. And the exergy of heat source was raised by increase coolant temperature to 105 deg C. As for improving the system efficiency, saturation temperature difference was expanded by improving performance of heat exchanger and by using high pressure turbine. And a recuperator which exchanges heat in working fluid between expander outlet and evaporator inlet was installed to recover the heat of working fluid at turbine generator. Then a working fluid pump was improved to reduce power consumption of the system. And Hydro-fluoro-ether was selected as suitable working fluid for the system for vehicles.
Technical Paper
2014-04-01
Pankaj G. Bhirud, Shreyas Shingavi, Ajay Virmalwar
Abstract Ashcan contributes to the aesthetics and elegance of the vehicle interiors. It is used to store the ash. Generally the ashcan is fitted on the console of the car. The operational requirement of ashcan is to open with minimum force but not at very low accelerations experienced during the vehicle bump event. Also closing force should be comparatively higher. The closing of the ashcan lid should ensure positive locking, which may be achieved by using cam and follower locking mechanism. The other requirement is that it should be structurally durable enough to sustain the repetitive loading during its operation. Ashcan may undergo severe abusive loading during its operation. To simulate these operations and understand the physics of the problem, a multi-step non-linear analysis involving a complex contact situation is carried out. The scope of this paper is to explain the procedure of calculating the force required for closing and opening of the ashcan lid. The forces calculated using finite element analysis (F.E.A) are compared with physical test forces and the functionality failure is compared with field failure.
Technical Paper
2014-04-01
Bryan Styles, Jeffrey Santrock, Curtis Vincent, Michael Leffert, Narasimha Putcha
An evaluation methodology has been developed for assessing the suitability of R-1234yf in vehicles. This relates primarily to evaluating the flammability of R-1234yf in the engine compartment during a frontal collision. This paper will discuss the process followed in the methodology, the technical rationale for this process, and the results of the analysis. The specific types of analysis included in the methodology are: exhaust-system thermal characterization, computer simulated crash tests, actual crash tests, teardown and examination of crashed parts, and releases of refrigerant onto hot exhaust manifolds. Each type of analysis was logically ordered and combined to produce a comprehensive evaluation methodology. This methodology has been applied and demonstrates that R-1234yf is difficult to ignite when factors that occur in frontal crashes are simultaneously considered. Factors considered in this analysis include: crush and deformation of the vehicle structure, airflow in the engine compartment, exhaust system temperatures during different driving scenarios, and coolant release due to damage of the engine coolant system.
Technical Paper
2014-04-01
Zheng Zhong Wang, Youzhong Xu, Kuaichu Fan, Binglin Da
The series of work introduced in this paper is originated from a structural failure of the vehicle A/C (Air-Conditioner) pipe, and when many possible factors having been excluded, the main investigating endeavor is focused on RLD acquisition and analysis, which eventually leads to the successful design improvement. During this process, many important signal collectives, such as micro-strains, accelerations, and engine speed are provided by RLD acquisition in some predefined conditions. Subsequently, these signals are analyzed both in time and frequency domain. Furthermore, order analysis by correlation of acceleration and engine speed is also performed to find a definite reason. As a conclusion, the root cause to the crack is not excitation from the road, but mainly from the engine. Based on this conclusion, structure design is improved and is theoretically proved to be effective by the RLD comparison analysis. And the quantified validation to this work is given by the real road test finally.
Technical Paper
2014-04-01
Ravi Kiran Cheni, Chetan Prakash Jain, Revathy Muthiah, Srikanth Gomatam
Abstract Automotive OEMs quest for vehicle body light weighting, increase in Fuel efficiency along with significant cut in the emissions pose significant challenges. Apart from the effect on vehicle handling, the reduction of vehicle weight also results in additional general requirements for acoustic measures as it is an important aspect that contributes to the comfort and the sound quality image of the vehicle, thus posing a unique challenge to body designers and NVH experts. Due to these conflicting objectives, accurate identification along with knowledge of the transfer paths of vibrations and noise in the vehicle is needed to facilitate measures for booming noise dampening and vehicle structure vibration amplitude. This paper focuses on the application of a unique design and development of vehicle body structure anti-vibration dynamic damper (DD), unique in its aspect in controlling booming noise generated at a specific RPM range. Design methodology follows the concept of Mass-damper system on vehicle body or engine structure where panel with multi-degree of freedom vibrating at medium level frequency is transferred to damper which is vibrating at same resonant frequency in 180° opposite phase.
Technical Paper
2014-04-01
Changxin Wang, Deguang Fang, Fuxiang Guo
Abstract To find out the main excitation sources of a bus floor's vibration, modal analysis and spectral analysis were respectively performed in the paper. First we tested the vibration modal of the bus's floor under the full-load condition, and the first ten natural frequencies and vibration modes were obtained for the source identification of the bus floor's vibration. Second the vibration characteristic of the bus floor was measured in an on-road experiment. The acceleration sensors were arranged on the bus's floor and the possible excitation sources of the bus, which includes engine mounting system, driveline system, exhaust system, and wheels. Then the on-road experiment was carefully conducted on a highway under the four kinds of test condition: in-situ acceleration, uniform velocity (90km/h, 100km/h, 110km/h, 120km/h), uniform acceleration with top gear, and stall sliding condition with neutral gear. After that, by performing order tracking analysis and spectral analysis, the 1st order rotation frequency of the driveline and the 2nd order frequency of engine were identified to be the main cause of bus floor's vibration.
Technical Paper
2014-04-01
Tomoya Ishii, Tomohiro Sudo, Masanori Morikawa, Daisuke Nagahata
Abstract General analysis methods which are known as Transfer Path Analysis and Air borne Source Quantification have been extended to estimate forces of an air conditioner's parts and also clarify the path from air conditioner system. These results show noise transfer path to be improved. Originally, the existing methods are known to require considerable amount of time for the cause of complicated measurement to get analysis results. In the work of this paper, required measurement is simplified, and time reduction of 50% is achieved without critical decrease in analysis accuracy.
Technical Paper
2014-04-01
Rupesh Sonu Kakade, Prashant Mer
Abstract A human thermal comfort, which has been a subject of extensive research, is a principal objective of the climate control systems. Applying the results of research studies to practical problems requires quantitative information of the thermal environment parameters, such as the solar radiation. A photovoltaic-cell based sensor is commonly used in the automotive climate control systems for the measurement of solar radiation information. The erroneous information from the sensors can cause thermal discomfort. The erroneous measurement from sensors can be due to physical or environmental parameters. Shading of a solar sensor due to opaque vehicle body elements is one such environmental parameter that is known to give incorrect measurement. Analytical method that uses fundamental geometric principles is proposed to determine whether sensor is shaded, for a known location of the sun and for a given geometry of the vehicle passenger compartment. A corrective action to measured data when sensor is shaded that ensures thermal comfort is also presented.
Technical Paper
2014-04-01
Jeff D. Colwell
Abstract Results from a full-scale vehicle burn test involving a 1998 compact passenger car were used to evaluate vehicle fire dynamics and how burn patterns produced during the fire correlated with important characteristics of the fire, such as the area of origin. After the fire was initiated at the air filter in the engine compartment, the fire spread locally and, once the temperature near the origin reached about 750°C, the temperature at all but one location within the engine compartment began to increase. These temperatures continued to increase for the next 6 minutes and then a temperature gradient began to develop in the passenger compartment between the ceiling and the floor. About 5 minutes after the engine compartment became fully involved, the ceiling temperature reached about 590°C and flame spread within the passenger compartment increased. Over the next 4 minutes, the passenger compartment also became fully involved. The fire then spread to the trunk and the rear wheels before self-extinguishing.
Technical Paper
2014-04-01
Youcai Liang, Gequn Shu, Hua Tian, Haiqiao Wei, Xingyu Liang, Mingru Zhao
Abstract Cogeneration system has become a valuable alternative approach for cascade waste heat recovery (WHR). In this paper, a novel electricity-cooling cogeneration system (ECCS) based on organic Rankine cycle-absorption refrigeration cycle (ORC-ARC) combined system is proposed to recover the waste heat of marine engine. ORC was adopted in the higher temperature cycle, in which alternatives D4, MDM and MM were selected as the working fluids. An ARC was adopted in the lower temperature cycle to recover the heat of the working fluid at the regenerator outlet in ORC. It aims to satisfy refrigeration requirement aboard ship, in which a binary solution of ammonia-water is used as the working pairs. Electricity output, cooling capacity, total exergy output, primary energy ratio (PER) and exergy efficiency are chosen as the objective functions. The results show that the additional cooling capacity is up to 10.9 MW, and such an ECCS has improved the exergy efficiency by 51% compared to the basic ORC.
Technical Paper
2014-04-01
Xuan Wang, Ge-Qun Shu, Hua Tian, Youcai Liang, Xiangxiang Wang
Abstract Currently, the thermal efficiency of vessel diesels only reaches 48∼51%, and the rest energy is rejected to the environment in forms of exhaust, cooling water, engine oil and so on. Meanwhile, energy is required when generating electricity and fresh water that are necessary for vessels. A system that combines the ORC thermal electric generation system with the single-effect evaporating desalination system simultaneously driven by waste heat of charge air is proposed. The research object was 12S90ME-C9.2 diesel engine produced by MAN corp., and a calculation model of the system is built by MATLAB. The variation of the output power, the thermal efficiency and the freshwater production with some operational parameters of the combined system are calculated and analyzed. On the other hand, under the condition of an assumed freshwater production 110.3t/d, the variation of the charge air temperature at the outlet of the desalination evaporator with some operational parameters of the system is studied in the paper.
Technical Paper
2014-04-01
Ehsan Samadani, Leo Gimenez, William Scott, Siamak Farhad, Michael Fowler, Roydon Fraser
Abstract In electrified vehicle applications, the heat generated of lithium-ion (Li-ion) cells may significantly affect the vehicle range and state of health (SOH) of the pack. Therefore, a major design task is creation of a battery thermal management system with suitable control and cooling strategies. To this end, the thermal behavior of Li-ion cells at various temperatures and operating conditions should be quantified. In this paper, two different commercial pouch cells for plug-in hybrid electric vehicles (PHEVs) are studied through comprehensive thermal performance tests. This study employs a fractional factorial design of experiments to reduce the number of tests required to characterize the behavior of fresh cells while minimizing the effects of ageing. At each test point, the effects of ambient temperature and charge/discharge rate on several types of cell efficiencies and surface heat generation is evaluated. A statistical thermal ramp rate model is suggested which enables fast and accurate determination of cell surface temperature and heat generation where the vehicle is started from cold or warm environments at a range of constant currents over the entire state of charge (SOC) range.
Technical Paper
2014-04-01
Matthew Klein, Shijie Tong, Jae Wan Park
Abstract Optimizing the hardware design and control strategies of thermal management systems (TMS) in battery packs using large format pouch cells is a difficult but important problem due to the limited understanding of how internal temperature distributions impact the performance and lifetime of the pack. Understanding these impacts is difficult due to the greatly varying length and time scales between the coupled phenomena, causing the need for complex and computationally expensive models. Here, an experimental investigation is performed in which a set of fixed one-dimensional temperature distributions are applied across the face of a Nickel-Cobalt-Manganese (NCM) cathode lithium ion pouch cell in order to study the performance impacts. Effects on the open circuit voltage (OCV), Ohmic resistance, bulk discharge and charge resistance and instantaneous power are investigated. It is observed that temperature gradients have a negative impact on the bulk performance by lowering the OCV and also increasing the bulk discharge resistance.
Technical Paper
2014-04-01
Ehsan Samadani, Roydon Fraser, Michael Fowler
Abstract Despite significant progress toward application of Li-ion batteries in electric vehicles, there are still major concerns about the range of electric vehicles and battery life. Depending on the climate of the region where the vehicle is in use, auxiliary loads could also play a significant role on the battery performance and durability. In this paper, the effect of air conditioning (AC) load on the electric range and Li-ion battery life is evaluated. For this purpose, a thermodynamic model for the vehicle cabin is developed and integrated to a battery model. The thermodynamic model takes the ambient conditions, solar load, and the vehicle drive cycle as inputs and calculates the instantaneous cabin temperature and humidity. The battery model, which represents a Li-on battery pack installed on a fully electrified Ford Escape 2009, consists of a voltage source in series with a lump resistance, a thermal sub-model, and a degradation sub-model to predict the battery capacity fade. At an initial cabin temperature and a desired set point, the model is capable of predicting the required cooling load and its corresponding required battery power as well as reductions in the vehicle range and battery state of health (SOH).
Technical Paper
2014-04-01
Lothar Seybold, Bryan Styles, Ioannis Lazaridis, Hans-Joerg Kneusels
The European Commission (EC) as well as the United States Environmental Protection Agency (EPA) published legislations to regulate or encourage the use of low Global Warming Potential (GWP) refrigerants applied to Mobile Air Conditioning (MAC) systems. Europe mandates a GWP less than 150 of MAC refrigerants for new vehicle types. The thermodynamic refrigerant properties of R-1234yf are slightly different from the properties of R-134a, currently used in MAC systems. Although the basic material data show that R-1234yf is flammable, ignition tests performed for an automotive engine under-hood environment reveal design and packaging influences of its ignition behavior. After extensive collaborative research in 2009, the Society of Automotive Engineers Cooperative Research Team (SAE CRP1234) concluded that R-1234yf is suitable for use in automotive applications. Further ignition risk assessment regarding R-1234yf usage in MAC systems was done by SAE CRP1234-4 in 2013. They concluded that “risks are still very small compared to the risks of a vehicle fire from all causes and well below risks that are commonly viewed as acceptable by the general public.”
Technical Paper
2014-04-01
Mathias Poklitar, Lothar Seybold
As part of the launch of the refrigerant R-1234yf there were a number of studies done regarding the ignition behavior of this new refrigerant in passenger cars. These tests were conducted by a number of automobile manufacturers, component suppliers, and the refrigerant supplier under laboratory conditions at the component and vehicle level. In November 2009 the international automotive industry concluded that the R-1234yf can be used safely in automotive air conditioning systems. Further tests were conducted by different automobile manufacturers, suppliers, and the refrigerant supplier under various laboratory and vehicle operation conditions means hot surfaces in the engine compartment. A number of vehicle manufactures have conducted full vehicle crash tests. In this paper, real world accidents are analyzed using the German In-Depth Accident Study (GIDAS) database as well as the thermal parameters for ignition of R-1234yf, i.e. concentration and surface temperature to create a worst-case scenario.
Technical Paper
2014-04-01
Kathleen Ku, Michael Tschirhart
Abstract Displays that support complex graphics in driver information (DI) systems allow for the presentation of detailed visual data by employing a range of static (fixed image) and/or dynamic (moving image) design approaches. Such displays are gaining market share across a wide range of mainstream vehicles as the availability and cost of such technologies improves. Although a range of 2D, rendered 3D, and 3D imaging (or stereoscopic) information displays have been demonstrated throughout the automotive industry in recent years, there is limited empirical research examining consumer preference of the respective approaches or their influence on driving related tasks. The vehicle environment is known to be a demanding context for efficiently displaying information to the driver. Research in 3D [1, 2] reveals some of the factors that influence its acceptance and effective use, but there is limited research on the effects of 3D-related design elements when used in a driver-vehicle interface.
Technical Paper
2014-04-01
Michael Tschirhart, Kathleen Ku
Abstract The vehicle environment is known to be a demanding context for efficiently displaying information to the driver. Research in typography reveals some factors that influence reading performance measures, but there is limited research on the influence of typographic design elements in a driver-vehicle interface on user performance with a simulated driver task. Participants in these studies completed a set of vehicle infotainment tasks that involved a text-based item search in a custom-designed interface that employed a family of Helvetica Neue fonts, in a static environment and a driving simulator environment. Analysis of the data from the two studies reveals a modest but statistically significant effect of font on certain driving-related task performance measures. In both studies, fonts with intermediate values of character width and line thickness were associated with the best performance on a simulated driving task. The results of this study suggest that using typefaces with intermediate values of certain intrinsic design factors may serve as a simple and effective means of improving vehicle user interfaces.
Technical Paper
2014-04-01
Zun Wang, Jaehoon Han, Devadatta Mukutmoni
Abstract At the onset of soak, air and surface temperatures in an engine bay enclosure are elevated since temperature of heat sources are high while convective cooling is sharply reduced as a result of airflow being shut off from the inlet grilles of the vehicle leading to temperature spikes. Accurate simulation of this important thermal and flow regime that is natural convection driven, highly transient and complex is therefore very important. In this investigation, we simulate flow in the engine bay at the onset of soak with fixed thermal boundary conditions where the geometries representing the engine bay and components are simplified. Good agreement was observed with detailed experimental data available in references for both velocities and temperatures.
Technical Paper
2014-04-01
Armin Traussnig, Heinz Petutschnig, Andreas Ennemoser, Michael Stolz, Mauro Tizianel
Abstract In order to meet current and future emission and CO2 targets, an efficient vehicle thermal management system is one of the key factors in conventional as well as in electrified powertrains. Furthermore the increasing number of vehicle configurations leads to a high variability and degrees of freedom in possible system designs and the control thereof, which can only be handled by a comprehensive tool chain of vehicle system simulation and a generic control system architecture. The required model must comprise all relevant systems of the vehicle (control functionality, cooling system, lubrication system, engine, drive train, HV components etc.). For proper prediction with respect to energy consumption all interactions and interdependencies of those systems have to be taken into consideration, i.e. all energy fluxes (mechanical, hydraulically, electrical, thermal) have to be exchanged among the system boundaries accordingly. However, it is very important that the level of detail of the VTMS model fits to the current phase of the vehicle development process.
Technical Paper
2014-04-01
Chengyu Zhang, Ge-Qun Shu, Hua Tian, Haiqiao Wei, Guopeng Yu, Youcai Liang
Abstract This paper presents a model system TEG-DORC that employs thermoelectric generator (TEG) as a topping cycle integrated with a dual-loop organic Rankine bottoming cycle (DORC) to recover exhaust heat of internal combustion engine (ICE). The thermodynamic performance of TEG-DORC system is analyzed based on the first and second law of thermodynamics when system net output power Wnet, thermal efficiency ηth, exergy efficiency ηe and volumetric expansion ratio are chosen as objective functions. The model has many parameters that affect combined system performance such as TEG scale, evaporation pressure of high temperature ORC loop (HT loop) Pevp,HT, condensation temperature of HT loop Tcond,HT. It is suggested that HT loop has a vital influence on system performance. The results show that TEG-DORC system can significantly improve system performance, and system net output power gets maximum (30.69kW) when Tcond,HT is 370K and Pevp,HT is 4MPa, accordingly, the absolute effective thermal efficiency increases by 5.2%.
Technical Paper
2014-04-01
Hai Wu, Wen Chen, Meng-Feng Li, Xinlei Wang
Abstract A hot and cold water mixing process with a steam condenser and a chilled water heat exchanger is set up for an engine EGR fouling test. The test rig has water recycled in the loop of a pump, heat exchangers, a three-way mixing valve, and a test EGR unit. The target unit temperature is controlled by a heating, cooling and mixing process with individual valves regulating the flow-rate of saturated steam, chilled water and mixing ratio. The challenges in control design are the dead-time, interaction, nonlinearity and multivariable characteristics of heat exchangers, plus the flow recycle in the system. A systems method is applied to extract a simple linear model for control design. The method avoids the nonlinearity and interaction among different temperatures at inlet, outlet and flow-rate. The test data proves the effectiveness of systems analysis and modeling methodology. As a result, the first-order linear model facilitates the controller design. The simulation studies with internal recycle processes produced promising results.
Technical Paper
2014-04-01
Manuel Lorenz, Dusan Fiala, Markus Spinnler, Thomas Sattelmayer
Abstract Cabin heating and cooling loads of modern vehicles, notably electrically driven, represent a major portion of the overall vehicle energy consumption. Various concepts to reduce these loads have thus been proposed but quantitative experimental analysis or numerical predictions are scarcely available. Conventional 1D or zonal cabin models do not account adequately for strongly inhomogeneous cabin climate conditions. In this paper a new cabin model is presented, which delivers both temporally and spatially resolved data. The model uses a dynamic coupling algorithm including a CFD simulation of the cabin airflow, a model of the cabin structure and the detailed passenger Fiala Physiological Comfort (FPC) model. The coupling not only includes heat transport between the cabin air and the surrounding surfaces, but also considers important interactions with the occupants, including e.g. the release of moisture into the cabin air by respiration and sweating predicted by the Fiala Physiological Comfort model and the heat exchange between occupant body parts and solid surfaces by radiation and conduction.
Technical Paper
2014-04-01
B. Vasanth, Jose Bright, Pavan Reddy, Sathish Kumar S, Murali Govindarajalu
Abstract In an Automotive air conditioning system, the air flow distribution in the cabin from the HVAC (Heating, ventilation and air conditioning), ducts and outlets is evaluated by the velocity achieved at driver and passenger mannequin aim points. Multiple simulation iterations are being carried out before finalizing the design of HVAC panel duct and outlets until the target velocity is achieved. In this paper, a parametric modeling of the HVAC outlet is done which includes primary and secondary vane creation using CATIA. Java macro files are created for simulation runs in STAR CCM+. ISIGHT is used as an interface tool between CATIA and STARCCM+. The vane limits of outlet and the target velocity to be achieved at mannequin aim points are defined as the boundary conditions for the analysis. Based on the optimization technique and the number of iterations defined in ISIGHT, the vane angle model gets updated automatically in CATIA followed by the simulation runs in STARCCM+. Based on the results vane angle will get updated and the iterations continues automatically till the target velocity is met at the aim points.
Technical Paper
2014-04-01
Mitsuru Enomoto, Michiko Kakinuma, Nobuhito Kato, Haruo Ishikawa, Yuichiro Hirose
Abstract Design work for truck suspension systems requires multi-objective optimization using a large number of parameters that cannot be solved in a simple way. This paper proposes a process-based systematization concept for ride comfort design using a set-based design method. A truck was modeled with a minimum of 13 degrees of freedom, and suspension performance under various vehicle speeds, road surface conditions, and load amounts was calculated. The range of design parameters for the suspension, the range of performance requirements, and the optimal values within these ranges were defined based on the knowledge and know-how of experienced design engineers. The final design of the suspension was installed in a prototype truck and evaluated. The performance of the truck satisfied all the objectives and the effectiveness of the set-based design approach was confirmed.
Viewing 121 to 150 of 9785

Filter

  • Article
    551
  • Book
    15
  • Collection
    17
  • Magazine
    338
  • Technical Paper
    7422
  • Standard
    1442
  • Article
    1442