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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
Kevin L. Snyder, Jerry Ku
Abstract The Wayne State University (WSU) EcoCAR2 student team is investigating powertrain optimizations as a part of their participation in the EcoCAR2 design competition for the conversion of a 2013 Chevrolet Malibu into a plug-in hybrid. EcoCAR2 is the current three-year Department of Energy (DoE) Advanced Vehicle Technical Competition (AVTC) for 15 select university student teams competing on designing, building, and then optimizing their Plug-In Hybrid conversions of GM donated vehicles. WSU's powertrain design provides for approximately 56-64 km (35-40 miles) of electric driving before the Internal Combustion Engine (ICE) powertrain is needed. When the ICE is started, the ICE traditionally goes through a cold start with the engine, transmission, and final drive all at ambient temperature. The ICE powertrain components are most efficient when warmed up to their normal operating temperature, typically around 90-100 °C. There are now some conventional vehicles currently available that employ active warm-up to recover waste heat from hot engine coolant to more quickly heat up the transmission fluid for reduced parasitic losses to improve fuel economy by approximately 2%. [1] [2] The WSU student team is investigating the improvements to fuel consumption (FC) of the ICE powertrain operation in the team's plug-in hybrid through pre-heating the ICE powertrain components before the engine is started.
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
Xiao Hu, Scott Stanton
Abstract Due to growing interest in hybrid and electric vehicles, li-ion battery modeling is receiving a lot of attention from designers and researchers. This paper presents a complete model for a li-ion battery pack. It starts from the Newman electrochemistry model to create the battery performance curves. Such information is then used for cell level battery equivalent circuit model (ECM) parameter identification. 28 cell ECMs are connected to create the module ECM. Four module ECMs are connected through a busbar model to create the pack ECM. The busbar model is a reduced order model (ROM) extracted from electromagnetic finite element analysis (FEA) results, taking into account the parasitic effects. Battery thermal performance is simulated first by computational fluid dynamics (CFD). Then, a thermal linear and time-invariant (LTI) ROM is created out of CFD solution. The thermal LTI ROM is then two-way coupled with the battery pack ECM to form a complete battery pack model. Thanks to the ROM technology, such a battery pack model can finish a complete charge discharge cycle within seconds of simulation time.
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
Sung Young Shin, Sang Dong Lee, Bong Chul Go
Abstract In terms of the responsive quality of cars, reducing the vibration of car seats is very important, as this vibration is transmitted directly to the driver. Here, a sensitivity analysis method was used to reasonably reduce the vibration of car seats at minimal cost. A laboratory test was conducted under two excitation conditions: first, vibration in idle state; second, random vibration not exceeding 100 Hz. To determine the reliability of the laboratory test, the actual vibration in idle state was simulated in a multi-axial simulation table for the idle excitation environment of cars that are sensitive to even the smallest changes in the environment. The frequencies of interest were selected by adding the sums of frequency response functions measured at the 24 nodal points of interest under the two excitation conditions. Sensitivity factors were derived at the 24 nodal points of interest and a design modification plan with relatively large sensitivity factors was suggested to reinforce the overall rigidity of the part modules containing the points of interest.
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
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
Kesav Kumar Sridharan, Ravish Masti, Ravi Kumar, Jiancheng Xin, Wendong Wang, Henry Kong
Abstract In hybrid electric vehicles (HEVs) and full electric vehicles (EVs), efficient electrical power management with proper supply of power at the required voltage levels is essential. A DC (Direct Current)-DC converter is one of the key electrical units in a HEV/EV. The DC-DC converter dealt in the present work is intended to create the DC voltages necessary to power the accessories. The electronic circuit in this DC-DC converter consists of high power devices like Metal-Oxide Semiconductor Field-Effect Transistors (MOSFETs), inductors, transformers, etc. mounted on a printed circuit board (PCB). The DC-DC converter interacts with a high voltage battery pack and supplies a low voltage power to the accessory battery. Due to this power handling operation, the devices in the convertor experience high temperatures. The temperature rise of the devices beyond the permissible limits could be detrimental to an efficient and safe operation of the converter. This paper deals with a robust and optimal thermal design of an air-cooled DC-DC Converter in order that the temperature (primary design parameter) of each of the devices is at a minimum and below the corresponding permissible limit of the device.
Technical Paper
2014-04-01
Kamalesh Bhambare, Junya Fukuyama, Jaehoon Han, Kosuke Masuzawa, Akihiro Iwanaga, Steven Patterson
Abstract The climate inside a vehicle cabin is affected by the performance of the vehicle HVAC system, the thermal characteristics of the vehicle structure and the components, as well as the external environmental conditions. Due to the complex interactions among these various factors, the flow field and the temperature distribution can be very complicated. The need for a fully three-dimensional transient analysis is increasing in order to provide sufficiently detailed information that can be used to improve the vehicle design. In this study, a numerical simulation methodology to predict the local climate conditions in a passenger vehicle cabin is presented. The convective heat transfer from both the exterior and the interior of the cabin were calculated by three dimensional CFD simulations using a Lattice-Boltzmann method based flow solver. The conduction and the radiation effects including the solar loading were solved using a finite-difference based radiation-conduction thermal solver.
Technical Paper
2014-04-01
Yang Zou, Huize Li, Predrag Hrnjak
Abstract Lubricant in compressor usually flows out with refrigerant. Thus, it is evitable for lubricant to be present in the heat exchanger, which significantly affects the heat exchanger performance. This paper is to investigate the effects of PAG oil on R134a distribution in the microchannel heat exchanger (MCHX) with vertical headers and to provide a tool to model R134a (with oil) distribution and its effects on MCHX capacity. The flow configuration in MCHX under the heat pump mode of the reversible system is mimicked in the experimental facility: refrigerant-oil mixture is fed into the test header from the bottom pass and exits through the top pass. It is found that a small amount of oil (OCR=0.5%) worsen the distribution. But further increasing OCR to 2.5% and 4.7%, the distribution becomes better. However, in a multi-pass microchannel heat exchanger model (considering oil effects), though the distribution is better and the capacity is closer to the uniform distribution case, the MCHX capacity decreases with respect to OCR because oil affects the heat transfer and pressure drop in the microchannel heat exchanger.
Technical Paper
2014-04-01
Gursaran D. Mathur
Abstract Experimental studies have been conducted to determine the energy stored in vehicle's Cockpit Module (CPM) at high ambient and at high solar heat loads for a MY2012 production vehicle. Detailed analysis has been done in this paper to show the influence of energy stored in various components (e.g., Instrument panel, HVAC system, heat exchanger, wire harness, etc.) contained within the CPM unit. Experiments were conducted to show the amount of energy stored at high ambient and solar conditions.
Technical Paper
2014-04-01
Sandip Pawar, Upender Rao Gade, Atish Dixit, Suresh Babu Tadigadapa, Sambhaji Jaybhay
Abstract The objective of the work presented in this paper is to provide an overall CFD evaluation and optimization study of cabin climate control of air-conditioned (AC) city buses. Providing passengers with a comfortable experience is one of the focal point of any bus manufacturer. However, detailed evaluation through testing alone is difficult and not possible during vehicle development. With increasing travel needs and continuous focus on improving passenger experience, CFD supplemented by testing plays an important role in assessing the cabin comfort. The focus of the study is to evaluate the effect of size, shape and number of free-flow and overhead vents on flow distribution inside the cabin. Numerical simulations were carried out using a commercially available CFD code, Fluent®. Realizable k - ε RANS turbulence model was used to model turbulence. Airflow results from numerical simulation were compared with the testing results to evaluate the reliability. Qualitative parameters such as mean Age of Air (AOA), Broadband Noise model, and Human Thermal Comfort Module (PMV/PPD) were used to gain deeper insight into the problem.
Technical Paper
2014-04-01
Xiaojie Lin, Hoseong Lee, Yunho Hwang, Reinhard Radermacher, Jungho Kwon, Chunkyu Kwon
Abstract In this paper, the application of the separate sensible and latent cooling (SSLC) technology to the mobile air conditioning (MAC) system was investigated. Conventional MAC systems utilize a low evaporating temperature to cool down the cabin air temperature and to remove moisture from humid air. In order to remove the moisture, the supply air temperature has to be below the dew point temperature of the cabin air. Therefore, a reheating process is necessary to increase the air temperature to an appropriate and comfortable level. However, energy is wasted in this reheating process, which results in the reduction of the fuel efficiency. Since the SSLC technology can provide an appropriate solution to these issues of conventional systems, it is proposed to apply the SSLC technology to the MAC system, which can eventually reduce the fuel consumption of the MAC system. In the proposed SSLC MAC system, the desiccant wheel is dedicated to handle most of latent load while the vapor compression cycle handles the remaining latent load and sensible load.
Technical Paper
2014-04-01
Huize Li, Predrag Hrnjak
Abstract The effect of lubricant on distribution is investigated by relating the flow regime in the horizontal inlet header and the corresponding infrared image of the evaporator. Visualization of the flow regime is performed by high-speed camera. R134a is used as the refrigerant with PAG 46 as lubricant, forming foam in all flow regimes. Quantitative information including foam location, foam layer thickness is obtained using a matlab-based video processing program. Oil circulation rate effect on flow regime is analyzed quantitatively.
Technical Paper
2014-04-01
Mark Zima, Mingyu Wang, Prasad Kadle, Joe Bona
Abstract Variable displacement compressors have proven to be more energy efficient than the equivalent compressor with fixed displacement for mobile A/C applications. Variable displacement compressors de-stroke rather than cycle to prevent the evaporator from freezing. Cycling an internally controlled variable compressor is counter intuitive, yet results in a 15-20% reduction in the energy used by the compressor as demonstrated by tests on multiple vehicle applications. Externally controlled variable compressors have the highest energy efficiency and extending cycling to these compressors during cool temperatures reduces the compressor energy consumption by 10%.
Technical Paper
2014-04-01
Yinhua Zheng
Abstract This paper addresses various ways to determine vehicle dual AC system charge level. Traditionally, either checking charge level plateau and/or using the certain condenser outlet subcooling magnitude are adopted to determine AC system charge level. It is challenging to determine refrigerant charge level in the following scenarios: (1) Some AC systems do not exhibit the flatted charge plateau. (2) The condenser outlet subcooling continues to rise. (3) The system has the requirements to run both front and aux evaporators, front evaporator only and aux evaporator only. It was found that compressor compression ratio of absolute discharge pressure to absolute suction pressure always presents the bath tub curve for all AC systems. When the system reaches the optimal charge level, the evaporator air outlet temperatures show the stable trend. In addition to the traditional condenser subcooling method, few approaches are presented in the paper. One way to determine the dual evaporator system charge level is: checking compressor compression ratios vs. charge level on the tests with (1) running both front and aux evaporators, (2) running front evaporator only (aux evaporator off).
Technical Paper
2014-04-01
Ruidong Yan, Jun-ye Shi, Han Qing, Jiangping Chen, Ji Song
Abstract Two phase flow mal-distribution in inlet header of the parallel flow evaporator will cause performance degradation, partial frosting and comfortableness problems. In order to solve these issues in heat pump system of electric vehicles, four types of small diameter tube and fin heat exchangers with different flow passage were designed and experimental measured in heat pump system of electric vehicles. The experimental results showed that in terms of performance, the small diameter tube and fin heat exchanger can reach even exceed the micro-channel heat exchanger on capacity and COP in heating model. Compared with micro-channel, the tube and fin heat exchanger with 4 inlets and 4 outlets can increase capacity from 2010W to 2689W, and increase COP from 2.6 to 2.8. However the frost/defrost experimental results showed that there was a decrease on the capacity of micro-channel heat exchanger after several frost/defrost periods. For the small diameter tube and fin heat exchangers, the condensate water was easier to be drained, thus partial pressure difference and heat exchange capacity would recover to the initial value eventually.
Technical Paper
2014-04-01
Guangning(Gary) Gao
Abstract Distance to empty (DTE) estimation is an important factor to electric vehicle (EV) applications due to its limited driving range. The DTE calculation is based on available energy of the battery and power usage by the powertrain components (e.g. electric motor) and climate control components (e.g. PTC heater and electric AC compressor). The conventional way of estimating the DTE is to treat the power consumed by the climate control system the same as the power by the powertrain for either instantaneous or rolling average estimation. The analysis in this study shows that the power consumption by the climate control system should be estimated based on the current ambient conditions and driver's input instead of using the recorded data from the past driving cycles. The climate control should also be considered separately from the powertrain in power usage rolling average calculation, which results in improvements in DTE estimation especially for extreme hot and cold conditions. Additionally, the climate control power consumption shows unique characteristics during the initial period of cabin climate control.
Technical Paper
2014-04-01
Jae Yeon Kim, Yong Nam Ahn, Shim Rok, Su Whan Kim, Wan Je Cho, Jy Choi, Hyun Keun Shin, Sang Ok Lee
Abstract In order to improve the fuel consumption ratio of the vehicle, a great deal of research is being carried out to improve air-conditioning efficiency. Increasing the efficiency of the condenser is directly connected to the power consumption of the compressor. This paper describes an experimental method of using an additional water-cooled condenser to reduce power consumption and decrease discharge pressure of the air-conditioning system. First, the principle of a combined cooling (water + air) method was evaluated theoretically. Next, experimental proof was conducted with the additional water-cooled condenser. The shape and structure is similar to the plate type of the transmission oil cooler used in a radiator. Through a number of tests, it was found that it is possible is to reduce power consumption of compressor by decreasing discharge pressure.
Technical Paper
2014-04-01
Essam F. Abo-Serie, Mohamed Sherif, Dario Pompei, Adrian Gaylard
Abstract A potentially important, but inadequately studied, source of passengers' exposure to pollutants when a road vehicle is stationary, with an idling engine, results from the ingestion of a vehicle's own exhaust into the passenger compartment through the HVAC intake. We developed and applied a method to determine the fraction of a vehicle's exhaust entering the cabin by this route. Further the influence of three parameters: ambient tail-wind speed, vehicle ground clearance and tail pipe angle, is assessed. The study applies Computational Fluid Dynamic (CFD) simulation to the distribution of exhaust gasses around a vehicle motorized with a 2.2 liter Diesel engine. The simulation employs efficient meshing techniques and realistic loading conditions to develop a general knowledge of the distribution of the gasses in order to inform engineering design. The results show that increasing tail-wind velocity, tail-pipe angle and ground clearance reduces the presence of CO and NO at the HVAC intake.
Technical Paper
2014-04-01
Michael Fritz, Frank Gauterin, Justus Wessling
Abstract Steadily rising energy prices and increasingly strict emissions legislation enforce the development of measures that increase efficiency of modern vehicles. An important contribution towards more efficient vehicles is the introduction of measures regarding auxiliary units. These measures increase the gross efficiency of a vehicle and therefore also the vehicle's range. Among the auxiliary power units of a vehicle like a long-haul truck, the refrigerant compressor generally consumes the biggest amount of energy. Therefore, it is reasonable to focus efficiency-increasing efforts on optimizing the A/C system. An important tool used in the development of optimization approaches is the simulation of the relevant systems. This allows a cost-optimized evaluation of the optimization approaches and also lets the engineer compare multiple variations of these approaches within a short period of time. For a significant evaluation of the potentials to be expected by implementation of different measures and variations optimizing the A/C system, it is necessary to simulate these under several climatic conditions.
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
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
Charles Sprouse III, Christopher Depcik
Abstract Significant progress towards reducing diesel engine fuel consumption and emissions is possible through the simultaneous Waste Heat Recovery (WHR) and Particulate Matter (PM) filtration in a novel device described here as a Diesel Particulate Filter Heat Exchanger (DPFHX). This original device concept is based on the shell-and-tube heat exchanger geometry, where enlarged tubes contain DPF cores, allowing waste heat recovery from engine exhaust and allowing further energy capture from the exothermic PM regeneration event. The heat transferred to the working fluid on the shell side of the DPFHX becomes available for use in a secondary power cycle, which is an increasingly attractive method of boosting powertrain efficiency due to fuel savings of around 10 to 15%. Moreover, these fuel savings are proportional to the associated emissions reduction after a short warm-up period, with startup emissions relatively unchanged when implementing a WHR system. Due to the absence of prior DPFHX research and the unique heat transfer process present, this effort describes construction of a prototype DPFHX and subsequent WHR experiments in a single cylinder diesel engine test cell with a comparison between heat exchanger performance with and without DPF cores installed.
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
Saiful Bari, Shekh Rubaiyat
Abstract The heat from the exhaust gas of diesel engines can be an important heat source to provide additional power using a separate Rankine Cycle (RC) or an Organic Rankine Cycle (ORC). Water is the best working fluid for this type of applications in terms of efficiency of the RC system, availability and environmental friendliness. However, for small engines and also at part load operations, the exhaust gas temperature is not sufficient enough to heat the steam to be in superheated zone, which after expansion in the turbine needs to be in superheated zone. Ammonia was found to be an alternate working fluid for these types of applications which can run at low exhaust temperatures. Computer simulation was carried out with an optimized heat exchanger to estimate additional power with water and ammonia as the working fluids. ANSYS 14.0 CFX software was used for the simulation. It was found that at full load 23.7% and 10.9% additional power were achieved by using water and ammonia as the working fluids respectively.
Technical Paper
2014-04-01
Pengyi Cui, Bin Xu
Abstract Air purifier has been prevalently used in the passenger vehicle cabins to reduce in-cabin UltraFine Particle (UFP) concentration. In this study, Computational Fluid Dynamics (CFD) was applied to simulate the in-cabin UFP transport and distribution under different ventilation modes with different characteristics of the air purifier. Ventilation settings, air purifier settings, and air purifier location were identified as the important factors determining the in-cabin UFP distribution and transport. Downward ventilation airflow direction and smaller ventilation air velocity can be considered by the drivers for a lower in-cabin UFP concentration. Upward airflow direction from the air purifier's inlet and larger air velocity were recommended since it led up to 50% in-cabin UFP reduction. Air purifier installed at middle ceiling of the cabin develops the most efficient airflow for UFP removal. Explicit relationships between in-cabin UFP distribution and the air purifier settings were presented as a reference to facilitate cabin air purifier design for more efficient in-cabin UFP removal.
Technical Paper
2014-04-01
Shivakumar Banakar, Dirk Limperich, Ramesh Asapu, Vaishnavi Panneerselvam, Madhu Singh
Abstract Air-cooled fin and tube heat exchangers are used as a condenser in the conventional automotive Heating Ventilation & Air-Conditioning (HVAC) systems. In this study, the use of liquid cooled plate heat exchanger as a condenser in the automotive HVAC systems has been investigated. In the proposed configuration, the cabin heat absorbed by the refrigerant in HVAC system is rejected to the coolant through a liquid cooled condenser and then to the ambient air through a low temperature radiator. Hence, the proposed configuration combines heat rejection from HVAC system with a low temperature radiator circuit of power train cooling. Mixture of Ethylene glycol & Water (coolant), which is used in power train cooling system, is used as secondary fluid in the condenser. Primarily, work done involves design of a liquid cooled condenser, determining boundary conditions for the coolant circuit and evaluation of overall performance of the refrigeration cycle in the HVAC system at various operating conditions.
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