Display:

Results

Viewing 61 to 90 of 10003
2015-04-14
Technical Paper
2015-01-0613
Donghong Ning, James Coyte, Hai Huang, Haiping Du, Weihua Li
Heavy duty vehicles suffer from detrimental vibrations which have significant influence to the operator’s comfort, health and safety. Especially, long term exposures to vibration with a frequency range between 0.5 and 10Hz will severely damage the driver’s backbone. Tires, chassis suspension and seat suspension are three traditional methods to isolate vehicles vibration, but it is generally difficult to modify the parameters of tires and chassis suspension, even many approaches are proposed for the performance of chassis suspension. On the other hand, the seat suspension system is easy to modify and optimize. Therefore, seat suspension has been employed as a simple and effective method to isolate vehicle vibration transmitted to the driver’s body. Studying the vibration characteristics of seat suspension is one important step for seat suspension design.
2015-04-14
Technical Paper
2015-01-1279
Pengfei Lu, Chris Brace, Bo Hu
After years of study and improvement, turbochargers in passenger cars now generally have very high efficiency. This is advantageous, but on the other hand, due to their high efficiency, only a small proportion of the exhaust energy is needed for compressing the intake air, which means further utilization of waste heat is restricted. From this point of view, a turbo compounding arrangement has significant advantage over a turbocharger in converting exhaust energy as it is immune to the upper power demand limit of the compressor. However, with the power turbine in series with the main turbine, power losses are incurred due to the higher back pressure which increases the pumping losses. This paper evaluates the effectiveness of turbo compounding a 2.0 litres gasoline engine and seeks to draw a conclusion on whether the power produced is able to offset the increased pumping work.
2015-04-14
Technical Paper
2015-01-1457
Aditya Belwadi, Richard Hanna, Audrey Eagle, Daniel Martinez, Julie Kleinert, Eric Dahle
Automotive interior design optimization must balance the design of the vehicle seat and occupant space for safety, comfort and aesthetics with the accommodation of add-on restraint products such as child restraint systems (CRS). It is important to understand the breadth of CRS dimensions so that this balance can be successfully negotiated. Previously this was addressed with the advent of advanced air bag systems, when emphasis was placed on the design and development of surrogate child restraints, which were used, in developing and testing occupant sensing and classification systems. CRS design is constantly changing. In particular, the introduction of side impact protection for CRS as well as emphasis on ease of CRS installation has likely changed key design points of any child restraints. This ever-changing target puts pressure on the vehicle manufacturers to keep their vehicle seats and occupant space compatible.
2015-04-14
Technical Paper
2015-01-1608
Davide Di Battista, Marco Mauriello, Roberto Cipollone
Internal combustion engines are the most important source of propulsive energy in the transportation sector. The expectations of more efficient and performing engines have to match with environmental issues that lead to cleaner vehicles. In fact, the awareness of oil shortage and greenhouse effect has led international governments to impose energy consumption levels which reflects on CO2 emissions: this commitment adds to the emission targets (CO, HC, NOX, PM) which proceed continuously toward lower levels. All of these limits will provide a huge effort on engine and vehicle efficiency with non-negligible costs. CO2 reductions appears the most important issue and it is representing the technological future driver. A smart way match to fulfill the targets concerning CO2 emission is to recover energy usually wasted and re-use it for engine and vehicle needs.
2015-04-14
Technical Paper
2015-01-1609
Roberto Monforte, Francesco Lovuolo, Matteo Rostagno, Riccardo Seccardini, Teron Matton
New MAC Technologies: Fuel Efficiency Effect in Real Driving of the air intake flap management Authors: R. Monforte (CRF), M.M. Rostagno (CRF), R. Seccardini (CRF), F. Lovuolo (Altran) Following the development of new technologies in Vehicle Thermal Management aiming to both reducing the thermal load to be managed by the Mobile Air Conditioning and enhancing its efficiency, a prediction tool based on the AMESim platform was developed at CRF in the Interiors & Engine Systems Area dedicated to predict the effect of the implementation of sensors monitoring both the relative humidity and the CO2 concentration (taking into account passenger moisture and carbon dioxide production). This model is implemented with the usual comfort inputs (CO2 and r.H. acceptable ranges), it considers the system variables influencing the comfort and predicts the grow-up of both relative humidity and CO2 concentration in the cabin compartment in any driving cycle depending on the number of occupants.
2015-04-14
Technical Paper
2015-01-1610
Xiaomeng Shen, Gangfeng Tan, Quan Zhou, Zhongjie Yang, Min Hua
The Organic Rankine Cycle System is an effective approach for recovering the engine exhaust thermal energy. The physical characteristic of the Rankine fluid is the key factor for the capacity and the stability of the expander power output when the engine works in varies condition decided by the road and traffic conditions. In the research, the influences of the evaporator organic medium states and flow rate on the expander power output are fully analyzed for the sufficient utilization of the waste thermal energy. Firstly, the exhaust characteristics of the diesel engine were processed by the data of the bench test. Then, the integral mathematical model of the Organic Rankine Cycle was built. Based on the comparison for the 2-phrase and 3-phrase evaporator, the influence for expander output are analyzed especially emphasis on the factors of engine working condition, the flow rate, temperature and state of Rankine fluid.
2015-04-14
Technical Paper
2015-01-1604
Tianwei (Thomas) Wang, John R. Wagner
**ABSTRACT Smart thermal management systems can positively impact the performance, fuel economy, and reliability of internal combustion engines. Advanced cooling systems typically feature multiple computer controlled actuators - a three way smart valve, a variable speed pump, and a variable speed electric radiator fan(s). To investigate the contributions of these electro-mechanical devices, a scale multifunction test bench was constructed which integrated these actuators, accompanying system sensors, and a controllable engine thermal load with real time data acquisition and control hardware/software. This paper presents a series of experimental studies that focus on the engine’s thermal transient response to various actuator input control combinations. From these test results, several key conclusions can be drawn.
2015-04-14
Technical Paper
2015-01-1606
Saroj Pradhan, Arvind Thiruvengadam, Pragalath Thiruvengadam, Marc C. Besch, Daniel Carder
Heavy-duty diesel (HDD) engines are the primary propulsion source for most heavy-duty vehicle freight movement and have been equipped with an array of aftertreatment devices to comply with more stringent emissions regulations. In light of concerns about the transportation sector's influence on climate change, legislators are introducing requirements calling for significant reductions in fuel consumption and thereby, greenhouse gas (GHG) emission over the coming decades. Advanced engine concepts and technologies will be needed to boost engine efficiencies. However, increasing the engine’s efficiency is inevitably linked to a reduction in thermal energy of the exhaust gas. Thus contributing to lower exhaust temperature of after-treatment activity, necessary for maintaining the aftertreatment system within a favorable temperature range.
2015-04-14
Technical Paper
2015-01-1605
Hee Sang Park
Electric powered vehicles rely on electric heater to heat the cabin of the vehicle. These heaters consume electric energy from the battery and cause depletion of the vehicle's range by 20~40%. In order to extend the range of electric vehicles, we need to increase the efficiency of HVAC. EV has waste heat but the heat power is much lesser than internal combustion engine and heat source is separated physically. In order to utilize waste heat to achieve better efficiency, heat collection , heat insulation, pre-heating are necessary. Based on the new concept system, we examined the effects of fuel efficiency 1) Heat collection: Heat sources are physically separated. In order to send these waste heat to the cabin. these parts have to be on the same cooling circuit. When every heat source is in the same circuit, heat loss is problem is happed because every heat source does not emit waste heat simultaneously. Motor and inverter make waste heat EV drive.
2015-04-14
Technical Paper
2015-01-1607
Chuen-Sen Lin, Vamshi Avadhanula, Vamsi Mokkapati, Daisy Huang, Brent Sheets
This paper presents test results of a 50 kilowatt (kW) Organic Rankine Cycle (ORC) system and proposed guidelines for how to effectively apply this system to the rural Alaska power industry. In rural Alaska, approximately 180 villages rely on off-grid diesel generators for power. Most of the generators have capacities of about 1 megawatt (MW) or less. In general, the average operation efficiencies are noticeably less than 40%, with the rest of the fuel energy becoming heat. If the heat is not applied for useful application, it is called waste heat. Most of the wasted heat is contained in engine exhaust and jacket fluid and eventually dissipates into the environment. For rural Alaska, waste heat for heating is most effective; in many cases, waste heat for power may be needed due to a variety of reasons.
2015-04-14
Journal Article
2015-01-0786
Keita Arato, Teruyuki Takashima
Recently, diesel engine has been researched and developed actively as a power source for not only heavy-duty vehicle but also passenger car. Improvement of fuel consumption is required in order to solve global warming issues and depletion of fossil oil resources. To improve brake thermal efficiency, improvement of indicate thermal efficiency and reduction of friction loss are essential. And to improve indicate thermal efficiency, it is important to improve theoretical thermal efficiency, combustion efficiency, and degree of constant volume. Reducing heat loss to the chamber wall is another factor for better thermal efficiency. In this study, a diesel engine with high compression ratio was of interest because of its higher theoretical thermal efficiency. Optimization of the combustion chamber shape was conducted by the three dimensional CFD simulation to reduce heat loss. Furthermore evaluation test using single cylinder engine was carried out.
2015-04-14
Technical Paper
2015-01-0347
Logesh Shankar Somasundaram, S Sriraman, Rakesh Verma
The paper aimed at numerically modeling the flow and thermal processes occurring in an agricultural tractor using Computational Fluid Dynamics (CFD) and determines the comfort level of the tractor operator during working condition. The motive of the investigation is to develop and demonstrate capabilities of CFD as an automotive analysis tool. The work describes a methodology that significantly streamlines the process of thermal flow taking place in a tractor by utilizing state-of-the art computer simulation of airflow and heat transfer. The numerical investigation carried out with a three-dimensional geometry of the vehicle assembly from the measurements taken from the vehicle. The geometry created with Pro E, WILDFIRE 3 formed the domain for the automatically generating discretized grids using ANSYS, ICEM CFD. The geometric CAD model used to generate the discretised grid contained the majority of the main components within the under hood environment.
2015-04-14
Journal Article
2015-01-0342
Forrest Jehlik, Eric Wood, Jeffrey Gonder, Sean Lopp
It is widely understood that cold-temperature powertrain operation negatively impacts vehicle fuel use due to heat transfer losses, increased friction (high viscosity engine oil), and enrichment strategies (accelerated catalyst heating). In addition, various drive cycle characteristics significantly impact overall consumption. However, relatively little effort has been dedicated to thoroughly quantifying these impacts across a large number of driving cycles and ambient conditions. This work leverages experimental vehicle data collected at various ambient conditions to develop a simplified modeling framework for quantifying thermal effects on energy consumption over a wide array of real-world usage profiles. Additionally, mitigation strategies including energy retention and exhaust heat recovery are explored with benefits quantified for each approach.
2015-04-14
Journal Article
2015-01-0357
Huize Li, Predrag Hrnjak
This paper presents a method of utilizing infrared images to quantify the distribution of liquid refrigerant mass flow rate in microchannel heat exchangers, which are widely used in automobile air conditioning systems. In order to achieve quantification, a relationship is built between the liquid mass flow rate through each microchannel tube and the corresponding air side capacity calculated from the infrared measurement of the wall temperature. After being implemented in a heat exchanger model, the quantification method is validated against experimental data. This method can be used for several types of heat exchangers and it can be applied to various heat exchanger designs.
2015-04-14
Journal Article
2015-01-0440
Julio Carrera, Alfredo Navarro, Concepcion Paz, Alvaro Sanchez, Jacobo Porteiro
Recent emissions standards have become more restrictive in terms of CO2 and NOx reduction. This has been translated into higher EGR rates at higher exhaust gas temperatures with lower coolant flow rates for much longer lifetimes. In consequence, Thermal Load for EGR components, specially EGR coolers, has been increased and thermal fatigue durability is now a critical issue during the development. Consequently a new Thermo-Mechanical Analysis (TMA) procedure has been developed in order to calculate durability. The TMA calculation is based on a Computational Fluid Dynamics simulation (CFD) in which a boiling model is implemented for obtaining realistic temperature predictions of the metal parts exposed to possible local boiling. The FEM model has also been adjusted to capture the correct stress values by submodeling the critical areas. Life calculation is based on a Multiaxial Fatigue Model that has also been implemented in FEM software for node by node life calculation.
2015-04-14
Journal Article
2015-01-0438
Ashley Lehman, Vesselin Stoilov, Andrzej Sobiesiak
This paper describes the application of the Fourier Amplitude Sensitivity Test (FAST) to investigate the thermal system performance of vehicle underbody components which are affected by variation in design parameters. The results from this study will pinpoint the design parameters which offer the greatest opportunity for improvement of thermal system performance and reliability. In turn, this method can save engineering time and resources. A mathematical model was first developed using Matlab for a vehicle underbody system consisting of a muffler, heat shield, and underbody panel. There were a number of input parameters identified. Some of these parameters deviate from their nominal value due to environmental factors, wear and ageing, or variation in the manufacturing process. These parameters include the emissivity of the muffler surface, the view factors between each component, and the temperature and velocity of the ambient air.
2015-04-14
Journal Article
2015-01-0441
Takashi Takiguchi, Yusuke Yano, Yasuhiro Takii, Nobuyuki Ohta
We require fast and accurate prediction to know the thermal performance for each car package. We established a highly accurate full-vehicle thermal prediction method applying the identification coefficients that we get from vehicle test results. The primary method of predicting this is Computational Fluid Dynamics (CFD) of conjugate heat transfer. CFD predicts external and exhaust gas flow, including their temperatures. Conditions taken into consideration are vehicle speed and temperature, heat rejection rate of the condenser, radiator, fan rotation speed, and exhaust gas flow. There are three identification coefficients required by each process. 1) Water temperature prediction process: Calculate ENG cooling loss and solar load by the 1D model, and input it into CFD as a heat rejection rate of the radiator and condenser.
2015-04-14
Journal Article
2015-01-0671
Saeed Jahangirian, Ashutosh Srivastava, Seyed Alireza Hosseini, Steven Ballard, Naiqiang Wu, John Kiedaisch
Durability assessments of modern engines often require accurate modeling of thermal stresses in critical regions such as cylinder head firedecks under severe cyclic thermal loading conditions. A new methodology has been developed and experimentally validated in which transient temperature distributions on cylinder head, crankcase and other components are determined using a Conjugate Heat Transfer (CHT) CFD model and a thermal finite element analysis solution. In the first stage, cycle-averaged gas side boundary conditions are calculated from heat transfer modeling in a transient in-cylinder simulation. In the second stage, a steady-state CHT-CFD analysis of the full engine block is performed. Volume temperatures and surface heat transfer data are subsequently transferred to a thermal finite element model and steady state solutions are obtained which are validated against CFD and experimental results.
2015-04-14
Technical Paper
2015-01-0346
Lei Dongxu, Minli Bai, Jizu Lv, Peng Wang, Chengzhi Hu, Yuyan Wang
Due to the latent heat of vaporization, the efficiency of boiling heat transfer is several times and even dozens of times higher than that of the convection heat transfer. With the improvement of power density of the engine, there are more requirements for engine cooling system design. It has been confirmed that the subcooled boiling did exist in the engine cooling. If boiling heat transfer can be reasonablely used, we can achieve the objective of enhancing heat transfer without changing the existing structure. In this paper, in order to quantitatively research the subcooled boiling in the engine, we simulated the subcooled boiling in the analog channel with the Euler multiphase model, found the importance of the turbulent dispersion. In additon, we explored the applicability of existing models to subcooled boiling, and compared the results with the experiment.
2015-04-14
Technical Paper
2015-01-0327
Elizabeth M. Patterson, Iman Goldasteh, Salamah Maaita
Abstract Recent progress in computer-aided engineering (CAE) has made it possible to model complex interdisciplinary multiphysics analyses. This paper investigated the sequential coupled thermal-structural analysis by examining the associated thermal stresses under simulated operational conditions close to the real situation. An evaluation of exhaust muffler strain due to thermal stresses was made by coupling Star-CCM+ CFD software and ABAQUS FEM structural analysis software. The study was made to evaluate discovered muffler durability test failure and to develop a countermeasure design. Failure of the muffler internal pipe was discovered after heat cycle durability testing. The internal pipe had broken into two pieces. In the first step, CFD analysis was done by thermo-flow simulation to determine the resulting heat distribution on the muffler assembly when subjected to the prescribed peak duty cycle temperature.
2015-04-14
Journal Article
2015-01-0339
Aimon Allouache, Smith Leggett, Matthew J. Hall, Ming Tu, Chad Baker, Haiyan Fateh
Abstract The performance of an organic Rankine cycle (ORC) that recovers heat from the exhaust of a heavy-duty diesel engine was simulated. The work was an extension of a prior study that simulated the performance of an experimental ORC system developed and tested at Oak Ridge National laboratory (ORNL). The experimental data were used to set model parameters and validate the results of that simulation. For the current study the model was adapted to consider a 15 liter turbocharged engine versus the original 1.9 liter light-duty automotive turbodiesel studied by ORNL. Exhaust flow rate and temperature data for the heavy-duty engine were obtained from Southwest Research Institute (SwRI) for a range of steady-state engine speeds and loads without EGR. Because of the considerably higher exhaust gas flow rates of the heavy-duty engine, relative to the engine tested by ORNL, a different heat exchanger type was considered in order to keep exhaust pressure drop within practical bounds.
2015-04-14
Journal Article
2015-01-0326
Takuya Yamaguchi, Yuzo Aoyagi, Noboru Uchida, Akira Fukunaga, Masayuki Kobayashi, Takayuki Adachi, Munemasa Hashimoto
Abstract In heavy duty diesel engines, the waste heat recovery has attracted much attention as one of the technologies to improve fuel economy further. In this study, the available energy of the waste heat from a high boosted 6-cylinder heavy duty diesel engine which is equipped with a high pressure loop EGR system (HPL-EGR system) and low pressure loop EGR system (LPL-EGR system) was evaluated based on the second law of thermodynamics. The maximum potential of the waste heat recovery for improvement in brake thermal efficiency and the effect of the Rankine combined cycle on fuel economy were estimated for each single-stage turbocharging system (single-stage system) and 2-stage turbocharging system (2-stage system).
2015-04-14
Technical Paper
2015-01-0335
Sandeep Makam, Christopher Dubbs, Yeliana Roosien, Feng Lin, William Resh
Abstract Due to ever-tightening CO2 regulations on passenger vehicles, it is necessary to find novel methods to improve powertrain system efficiency. These increases in efficiency should generally be cost effective so that the customer perceives that they add value. One approach for improving system efficiency has been the use of thermal energy management. For example, changing the flow of, or reusing “waste” heat from the powertrain to improve efficiency. Due to the interactions involved with thermal management, a system level approach is useful for exploring, selecting, and developing alternative solutions. It provides a structured approach to augment the right kind of synergies between subsystems and mitigate unintended consequences. However, one challenge with using these approaches early in a program is having appropriate metrics for assessing key aspects of the system behaviors.
2015-04-14
Journal Article
2015-01-1695
Satoki Tada, Takahiro Nagai, Naoki Shioda, Hirofumi Fujiu, Shunji Kumagai, Hideaki Abe, Yukihiro Isoda, Yoshikazu Shinohara
As an appropriate material for automotive thermoelectric generators, which directly convert waste heat of exhaust gas into electricity, we have developed Mg2(Si1-xSnx) thermoelectric materials with high thermoelectric performance. The performance is evaluated with the dimensionless figure of merit (ZT), and the ZT has been improved through the development of the fabrication process and the investigation of the optimum composition and dopant element. A novel liquid-solid reaction synthesis method incorporating hot-pressing for the sample fabrication was effective in reducing the thermal conductivity. The n-type Mg2(Si0.50Sn0.50) doped with Sb attained a high ZT of 1.1 at 620 K. The p-type Mg2(Si0.25Sn0.75) doped with Li and Ag simultaneously achieved a ZT of 0.3 at 600 K. The effective maximum power of n-type thermoelectric element and that of p-type were calculated with the thermoelectromotive force and the mean resistivity.
2015-04-14
Journal Article
2015-01-1526
Yasuyuki Onishi, Thomas Ramsay, Timothy Juan, James McKillen
A sports car exhibits many challenges from an aerodynamic point of view: drag that limits top speed, lift - or down force - and balance that affects handling, brake cooling and insuring that the heat exchangers have enough air flowing through them under several vehicle speeds and ambient conditions. All of which must be balanced with a sports car styling and esthetic. Since this sports car applies two electric motors to drive front axle and a high-rev V6 turbo charged engine in series with a 9-speed double-clutch transmission and one electric motor to drive rear axle, additional cooling was required, yielding a total of ten air cooled-heat exchangers. It is also a challenge to introduce cooling air into the rear engine room to protect the car under severe thermal conditions. This paper focuses on the cooling and heat resistance concept.
2015-04-14
Journal Article
2015-01-1709
Daniel Leighton
Electric drive vehicles (EDVs) have complex thermal management requirements not present in traditional internal combustion engine vehicles. In addition to cabin conditioning, the battery, power electronics, and electric motor drivetrain sub-systems also require thermal management. Many current generation EDVs utilize separate cooling systems for each of these sub-systems, which adds both weight and cost. Another issue for EDVs is the lack of abundant waste heat from the engine for cabin heating. In many cases EDVs use battery energy to heat the cabin via an electrical resistance heater, which results in vehicle range reductions of nearly 50% under cold ambient conditions. These EDV thermal challenges present an opportunity for integrated vehicle thermal management technologies which can reduce cost and weight, and enable efficient heating methods that increase vehicle range.
2015-04-14
Journal Article
2015-01-1689
Xu Song, Ryan Fortier, Scott Sarnia
The underhood hot air recirculation greatly impacts A/C system performance at idle and low vehicle speed conditions. The hot air recirculation can raise condenser cooling airflow temperature over ambient by 18°C, which lowers condenser cooling capacity and increases compressor work. Underhood airflow research suggests that a properly designed air duct is able to minimize hot air recirculation and improve the Compressors Coefficient of Performance (COP) at idle by 27%. This paper discusses underhood hot air recirculation testing methods, airflow distribution, and air duct design concepts. This dedicated air duct design indicates it should improve A/C emissions, which could contribute to meeting the Environmental Protection Agency’s (EPA) Green House Gas Emissions Regulations in North America.
2015-04-14
Journal Article
2015-01-0371
Rupesh Sonu Kakade, Prashant Mer
Human thermal comfort is a principal objective of the climate control systems such as the automotive air conditioning system. Applying the results of research studies on human thermal comfort to the practical problems require quantitative information of the thermal environmental parameters, such as the impinging solar radiation. Photovoltaic-cell based sensor is commonly used in automotive climate control systems for the measurement of impinging solar radiation intensity. The erroneous information from sensor can cause thermal discomfort. Such an erroneous measurement can be due to physical or environmental parameters. Shading of a solar sensor due to opaque body elements of vehicle is one such environmental parameter that is known to give incorrect measurement. Fundamental geometric principles can be used to determine if sensor is shaded, for a given position of the sun with respect to vehicle and for a given geometry of the vehicle passenger compartment.
2015-04-14
Journal Article
2015-01-0359
Satoki Uematsu, Toshiyuki Uehara, Toshiya Uchida, Gursaran D. Mathur
In last 10 years or so, a number of OEMs are designing vehicles with start-stop function to save energy and to reduce pollution. For these systems, the situations in which air-conditioning systems are used have been changing with a significant increase in adoption of idle-time reduction systems (no idling-system). Blower fan remain operating at idle condition while compressor stops in most cases for these systems. In this case, the air temperature at the vent outlets is likely to increase. The increase in the air temperature under range of thermal boundary conditions around the evaporator causes a concern of odor to occur. This paper describes and explains experimental studies on changes in heat and humidity at the air outlets according to the switching operation of compressor and root cause analyses of odor coming from air-conditioning system for vehicles with start-stop function.
2015-04-14
Journal Article
2015-01-1379
Hideki Matsumura, Shinichiro Itoh, Kenichi Ando
Recently, lithium ion cells are being used in more and more electric and hybrid motor vehicles. However, accidents due to thermal runaway of the cells have been reported, involving abnormal heat, smoke, and fire. Since each of these vehicles contains many cells, if the thermal runaway of one cell triggers that of another and thus causes thermal runaway propagation, a car fire or other serious accident may occur. This study aims to ensure the safety of motor vehicles with lithium ion cells. To identify such accident risks, we conducted a basic experiment to clarify the phenomenon of thermal runaway propagation following a thermal runaway. In the experiment, seven laminate-type lithium ion cells were tightly stacked one on another, with a thermocouple placed at the center of the surface of each cell. Then, the center of the cell in the middle of the seven stacked cells was overcharged to trigger a thermal runaway.
Viewing 61 to 90 of 10003

Filter