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2015-04-14
Technical Paper
2015-01-1712
Ram Vijayagopal, Aymeric Rousseau
This study looks at the impact of TEGs have on different types of light duty vehicles. UDDS, Highway and Combined 2 cycle procedures are used to evaluate the fuel economy benefits in these vehicles. These fuel economy benefits are then translated to gasoline savings and net present value of the monetary benefits. Previous studies had used TEG models that depend on exhaust flow traces recorded from the test bench. A better TEG model is developed which can estimate exhaust mass flow, and respond to variations in the exhaust flow. This model can also predict the temperature variations on the hot and cold side of the TEG modules. Better TEG modules are also modelled based on the published data from General Motors (GM). The heat dissipation through the TEG between the source and sink is modelled, but various other losses like contact losses or thermal losses within the TEG are not modelled.
2015-04-14
Technical Paper
2015-01-1122
Kengo Yabe, Toru Inagaki, Takashi Kondo
Abstract Seat vibration when a vehicle is idling or in motion is an issue in automobile development. In order to reduce this vibration, dynamic damper or inertia mass is widely used. These countermeasures increases vehicle's weight and causes bad fuel-efficiency. Some new ways to reduce the vibration without weight increase are needed. One of that is the floating seat. Seat vibration has been reduced by controlling seat resonance frequencies. In order to control resonance frequency, the structures of the seat-mounting unit are replaced with floating structures using rubber bushings. It was demonstrated that partially replacing the mounting unit with floating structures makes it possible to control the resonance frequencies of the entire seat. The issue of balancing vibration reduction with strength and durability and crash safety performance caused by the fitting of rubber bushings to the seat-mounting unit was addressed using stopper structures optimized for each type of input.
2015-04-14
Technical Paper
2015-01-0248
Hiroyasu Baba, Koji Kawasaki, Hideomi Kawachi
Abstract We have developed Li-ion battery heating system which is direct resistance heating for hybrid electric vehicles (HEV), plug-in hybrid vehicles (PHEV) and electric vehicles (EV) by use of an inverter and a motor. One relay is added between a positive terminal of Li-ion battery and one-phase (e.g. U-phase) of a three-phase motor. When additional relay is turned on, the motor coils, IGBTs (Insulated-gate bipolar transistor) and diodes in the inverter and a smoothing capacitor for the inverter constitute buck-boost DC to DC converter. IGBTs are controlled to repeat charging and discharging between the battery and the smoothing capacitor. We made a system prototype and examined battery heating capability. And also we optimized charging and discharging frequency from impedance and current to improve heat generation. This method can increase battery temperature from −20 degrees C to 0 degrees C in 5 minutes and can extend EV driving range.
2015-04-14
Technical Paper
2015-01-0505
Miguel Angel Reyes Belmonte, Colin D. Copeland, Drummond Hislop, George Hopkins, Adrian Schmieder, Scott Bredda, Sam Akehurst
Abstract Pressure and temperature levels within a modern internal combustion engine cylinder have been pushing to the limits of traditional materials and design. These operative conditions are due to the stringent emission and fuel economy standards that are forcing automotive engineers to develop engines with much higher power densities. Thus, downsized, turbocharged engines are an important technology to meet the future demands on transport efficiency. It is well known that within downsized turbocharged gasoline engines, thermal management becomes a vital issue for durability and combustion stability. In order to contribute to the understanding of engine thermal management, a conjugate heat transfer analysis of a downsized gasoline piston engine has been performed. The intent was to study the design possibilities afforded by the use of the Selective Laser Melting (SLM) additive manufacturing process.
2015-04-14
Technical Paper
2015-01-1623
Ivan Arsie, Rocco Di Leo, Stefano Falco, Cesare Pianese, Matteo De Cesare
Abstract International regulations continuously restrict the standards for the exhaust emissions from automotive engines. In order to comply with these requirements, innovative control and diagnosis systems are needed. In this scenario the application of methodologies based on the in-cylinder pressure measurement finds widespread applications. Indeed, almost all engine thermodynamic variables useful for either control or diagnosis can be derived from the in-cylinder pressure. Apart for improving the control accuracy, the availability of the in-cylinder pressure signal might also allow reducing the number of existing sensors on-board, thus lowering the equipment costs and the engine wiring complexity. The paper focuses on the detection of the engine thermal state, which is fundamental to achieve suitable control of engine combustion and after-treatment devices.
2015-04-14
Technical Paper
2015-01-1649
Kenji Matsumoto, Atsushi Takahashi, Tsutomu Inoue
Abstract In our preceding report [1], we showed that the thermal conductivity of a heat pipe dramatically improves during high-speed reciprocation. However, this cooling method has rarely been applied to car engine pistons because the thermal conductivity of commercially available heat pipes does not increase easily even if the pipe is subjected to high-speed reciprocation. In consideration of the data from our preceding report, we decided to investigate heat pipe designs for car engine pistons, propose an optimum design, and conduct thermal analysis of the design. As a result, we found that it is possible to transport heat from the central piston head area, where cooling is most needed, to the piston skirt area, suggesting the possibility of efficient cooling.
2015-04-14
Technical Paper
2015-01-0341
Georg Rauch, Johannes Lutz, Martin Werner, Sagar Gurwara, Peter Steinberg
For solving problems in the field of engine heat up and thermal deformation of an engine, transient CHT analysis has gained high importance. The transient results make it possible to identify the amount of heat and its specific transfer region. Furthermore, the transient temperature profiles are used to generate the deformation fields which are crucial for friction calculations. Despite these useful applications transient CHT is avoided due to the large computational resources. This paper introduces an innovative approach which uses the synergy effect of 1D and 3D simulation in order to bring down modeling and simulation time. At the same time the methodology sustains the spatial resolution of a 3D model. This goal is reached by reducing the 3D fluid side with its time consuming continuity, momentum, energy and turbulence equations to a simple but precise 1D model. The structure stays in the 3D manner.
2015-04-14
Technical Paper
2015-01-0340
Jan Eller, Thomas Binner, Heinrich Reister, Nils Widdecke, Jochen Wiedemann
There is a growing need for life-cycle data – so-called collectives – when developing components like elastomer bearings. Current extreme load cases are not sufficient for establishing such collectives. Consequently, the Idle load case is examined at Mercedes-Benz Car Group as a collective load case for Vehicle Thermal Management (VTM) numerical simulations in early development stages. It combines validation opportunities for HVAC, cooling and transmission requirements in hot-country-type ambient conditions. Experiments at climatic wind tunnels show steady conditions at the end of the case. With a standard Mercedes-Benz 7G transmission temperatures rise in driving gear and fall to a steady state during the subsequent section in parking gear. This effect propagates to elastomer bearings which are the focus of this study. Decoupling of the torque converter entails no dependence on transmission gear setting, anymore.
2015-04-14
Technical Paper
2015-01-0330
Iman Goldasteh, Shi-Ing Chang, Salamah Maaita, Gursaran Mathur
Proper flow distribution on the windshield and side windows is critical for adequate visibility while driving. Fog or ice which forms on the windshield is the main reason of invisibility and leads to major safety issue. It has been shown that proper clear visibility for the windshield could be obtained with a better flow pattern and uniform flow distribution in the defrost mode of the HVAC system. In this study, a three dimensional numerical model of a car cabin with full HVAC system was developed using Star-CCM+, a commercial CFD package. The Reynolds-Averaged Navier–Stokes equations (RANS) approach with the realizable two-layer k-ε turbulence model was employed for simulating the airflow field on the windshield for the defrost mode. The HVAC unit, ducts and defroster grille were included in the analysis in detail and air distribution on the windshield was studied.
2015-04-14
Technical Paper
2015-01-0349
Suvankar Manna, Yogendra Singh Kushwah
With stringent requirements of fuel efficiency and emissions, the airflow and thermal management within the under-hood environment is gaining significance day by day. While adequate airflow is required for cooling requirements under various vehicle operating conditions, it is also necessary to optimize it for reduced cooling drag and fan power. Hence, the need of the day is to maximize cooling requirements of Condenser, Radiator ,CAC and other heat exchangers with minimal power consumption. To achieve this objective and due to the complicated nature of 3D flow phenomenon within the under-hood environment, it is useful to perform 3D CFD studies during preliminary stages to shorten design time and improve the quality and reliability of product design. In this paper we present the results from a CFD under-hood analysis that was carried out for design, development and optimization of a CRFM (Condenser, Radiator and Fan Module).
2015-04-14
Technical Paper
2015-01-0348
Chuqi Su, Meng Xu, Naiqiang Tong, Yulian Chen
The potential for automotive exhaust-based thermoelectric generator (TEG) has been increasing with continuously advances in thermoelectric technology. In this paper, the thermal deformation of the TEG system is studied on the basis of the temperature distribution of the heat exchanger. The simulation analysis shows that the thermoelectric modules (TMs) on different positions of the heat exchanger have different thermal performance, which can significantly influence the power generation efficiency of the system. Meanwhile, it is found that the thermal performance is affected by the clamping mechanism, which has a greater effect on the cold side than the hot side. Following the simulations, bench tests are carried out to confirm the reasonability of the simulation results.
2015-04-14
Technical Paper
2015-01-0344
Yingchao Zhang, Weijiang Meng, Tao Chen, Yong Hao, Wei Ding
It is known that the automobile cabin thermal comfort, could keep the driver and passengers feel better which has a great effect on traffic safety. In this article, to the FAW truck cab, we did some research about the automobile cabin thermal comfort. Our plan is to calculate the air flow distribution and the temperature in steady and transient state when there is warm or cool flow. The heating and cooling experiment methods standard of cabin are based on the national standard and the automobile industry standard of China. Then the numerical simulation process becomes very important. So we used the commercial CFD code- STAR-CCM+ for study in this paper. Firstly, Geometry Clean up, we should process the cabin and the air conditioning pipe system individually, and make sure the closure of the internal surface and handle the wrap surface of the pipe.
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
Technical Paper
2015-01-0368
Janampally Sandeep Kumar Reddy, Shailendra Deopa, Abhay Sharma, Piyush Aggarwal
The condenser opening area plays a vital role in the A/C Performance of the vehicle particularly during the idling. This paper presents the detail study on the effects of the condenser opening area on the A/C performance. Based on the theory, the effect of the condenser opening area is studied and it is validated by the experimental results. Based on these results an optimum value of the condenser opening area required for the best A/C performance is concluded.
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
Technical Paper
2015-01-0350
Zhi Li, Gangfeng Tan, Jing Cai, Zhongjie Yang, YiRui Wang, Haobo Xu
Thermoelectric power generation could achieve the recovery of engine exhaust waste heat. For the conventional scheme, the hot-end of the thermoelectric module is connected with the exhaust pipe, while the cold-end is cooled through the engine cooling cycle. The variation of engine operating conditions brings the instability of the hot-end temperature, which affects the power generation performance of thermoelectric materials and increases the damage risk to the thermoelectric materials caused by the high temperature. This research adopts the heat transfer oil circulation as the intermediate fluid to absorb the dynamic heat flux of the engine exhaust so as to release the heat steadily to the hot-end of the thermoelectric module. The thermal characteristics of the target diesel engine exhaust gas are evaluated based on the experimental data firstly.
2015-04-14
Technical Paper
2015-01-0366
Cristian Rostiti, Stephanie Stockar, Marcello Canova
In a scenario where the automotive industry is striving to significantly improve the fuel economy of passenger cars, it is clear that reduction of ancillary loads plays a key role for achieving significant fuel consumption and emissions reductions. In a conventional passenger vehicle, the A/C system is the largest ancillary load and it has been shown that it can consume up to 9% of the engine power available at the crankshaft This paper approaches the problem of reducing the parasitic load of the A/C system as a multi-objective optimization problem. Starting from a validated control-oriented model of an automotive A/C system, an optimization problem is formalized. Specifically, the objective of the optimization is to achieve the best possible fuel economy over a driving cycle, while guaranteeing the passenger comfort in terms of cabin temperature and reduce the wear of the components, in this case the compressor clutch.
2015-04-14
Technical Paper
2015-01-0365
Gursaran D. Mathur
In a recent investigation (Mathur, 2014), the author had investigated the amount of energy stored in vehicle's Cockpit Module (CPM) at high ambient and at high solar heat loads for a MY2012 production vehicle. Detailed analysis was presented 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. This is a follow up study to the above investigation. In this investigation, same vehicle is used to determine the amount of energy stored at cold temperatures, say at -20°C temperature that is used for a majority of heating, windshield and window de-fogging and de-icing tests.
2015-04-14
Technical Paper
2015-01-1752
Alex Melin, David Kittelson, William Northrop
In recent years, there has been growing interest in using alternative cycles to the standard Otto cycle in an effort to improve efficiency and lower emissions of spark-ignition engines. One such proposed concept is the 5-stroke engine. The 5-stroke uses two types of cylinders, a combustion cylinder and expansion cylinder with a transfer port between them. Excess pressure in the combustion cylinder can be further expanded by using a second expansion cylinder to harness additional work; a practical implementation of the Atkinson Cycle. Since the expansion cylinder runs on a two-stroke cycle, an additional increase in efficiency can result by connecting two combustion cylinders to one expansion cylinder in a three cylinder configuration. Although previous work has investigated the performance of prototype 5-stroke engines compared to1-D modeling results, none have conducted a thorough study on the interactions of various design parameters.
2015-04-14
Technical Paper
2015-01-1753
Mario Vila Millan, Stephen Samuel
Nanofluids and thermal management strategy for Automotive Application Mario Vila Millan, Stephen Samuel Oxford Brookes University, United Kingdom Stringent emission norms introduced by the legislators over the decades have forced the automotive manufacturers to improve the fuel economy and emission levels of their engine continuously. This constant improvement leads to increased use of smart systems where components are controlled by the engine management systems to get a desired and optimized performance. Therefore, the emission levels of the modern engines are significantly lower than pre-1990 engines. However, the improvement in fuel economy is marginal when compared to that of the scale of improvement achieved for reducing emission levels. For example, approximately 30% of the total energy in the fuel is still being wasted through the cooling systems in the modern engines during normal operating conditions. This is even worse during the engine warm up.
2015-04-14
Technical Paper
2015-01-1650
Azmi Osman, Mohd Asmu'i Hussin, Shaiful Fadzil Zainal Abidin
Abstract The drive to reduce CO2 and fuel consumption from passenger cars requires improvements from various subsystems. In particular, the ever growing importance of effective and efficient thermal management will no doubt benefit the quest for more efficient vehicle. While many established automakers have decided to increase the sophistications of the engine cooling circuits through electronics, the increase in complexity and costs are still not desirable especially for A and B passenger car segments. With this in mind, simple mechanical based cooling systems with enhanced functionalities are in high demand. To meet such demand, a simplified engine split cooling circuit previously proposed, simulated and reported seems to be promising. To further verify the indicated advantages, a prototype unit was built and physically tested using a dynamometer with motoring capability.
2015-04-14
Technical Paper
2015-01-1651
Francisco Payri, Jaime Martin, Antonio Garcia, Ricardo Carreño
Abstract In recent years, the spread use of after-treatment systems together with the growing awareness about the climate change is leading to an increase in the importance of the efficiency over other criteria during the design of internal combustion engines. In this sense, it has been demonstrated that performing an energy balance is a suitable methodology to assess the potential of different injection or air management strategies, to reduce consumption as well as determining the more relevant energy terms that could be improved. In this work, an experimental energy balance with the corresponding comprehensive analysis is presented. The main objective is the identification of how the energy is split, considering internal and external balances. For this purpose, some parametric studies varying the coolant temperature, the intake air temperature and the start of the injection timing have been performed. The results quantify the effect of each parametrical study on engine efficiency.
2015-04-14
Technical Paper
2015-01-1653
Kenji Matsumoto, Hironori Harada, Hiroyoshi Taniguchi, Naoki Ito
Abstract Car engine piston cooling is an important technology for improving the compression ratio and suppressing the deformation of pistons. It is well known that thermal conductivity improves dramatically through the use of heat pipes in computers and air conditioners. However, the heat pipes in general use have not been used for the cooling of engines because the flow of gas and liquid is disturbed by vibration and the thermal conductivity becomes excessively low. We therefore developed an original heat pipe and conducted an experiment to determine its heat transfer coefficient using a high-speed reciprocation testing apparatus. Although the test was based on a single heat pipe unit, we succeeded in improving the heat transfer coefficient during high-speed reciprocation by a factor of 1.6 compared to the heat transfer coefficient at standstill. This report describes the observed characteristics and the method of verification.
2015-04-14
Technical Paper
2015-01-0878
Guanzhang He, Hui Xie
Abstract The performance of three different electric turbo-compounding systems under both steady and driving cycle condition is investigated in this paper. Three configurations studied in this paper are serial turbo-compounding, parallel turbo-compounding and electric assisted turbo-compounding. The electric power, global gain of the whole system (engine and power turbine) under steady operating condition is firstly studied. Then investigation under three different driving cycles is conducted. Items including fuel consumption, engine operating point distribution and transient response performance are analyzed among which the second item is done based on statistic method combined with the results obtained under steady operating conditions. Study under steady condition indicates that electric assisted turbo-compounding system is the best choice compared with the other two systems.
2015-04-14
Technical Paper
2015-01-1189
Satyam Panchal, Scott Mathewson, Roydon Fraser, Richard Culham, Michael Fowler
Abstract A major challenge in the development of the next generation electric and hybrid electric vehicle (EV and HEV) technology is the control and management of heat generation and operating temperatures. Vehicle performance, reliability and ultimately consumer market adoption are integrally dependent on successful battery thermal management designs. In addition to this, crucial to thermal modeling is accurate thermo-physical property input. Therefore, to design a thermal management system and for thermal modeling, a designer must study the thermal characteristics of batteries. This work presents a purely experimental thermal characterization of thermo-physical properties of a lithium-ion battery utilizing a promising electrode material, LiFePO4, in a prismatic pouch configuration. In this research, the thermal resistance and corresponding thermal conductivity of prismatic battery materials is evaluated.
2015-04-14
Journal Article
2015-01-1391
Scott Allen Ziolek, Joshua Pryor, Tony Schwenn, Adam Steinman
Optimizing climate seat systems requires increased complexity in seat design which in turn is driving a need for more detailed thermal simulation methods. This paper presents the model development considerations and results of a thermal simulation study aimed at improving the thermal seat comfort experience of Hyundai-Kia’s heated seating systems.
2015-04-14
Journal Article
2015-01-1184
Satyam Panchal, Scott Mathewson, Roydon Fraser, Richard Culham, Michael Fowler
Abstract The performance, life cycle cost, and safety of electric and hybrid electric vehicles (EVs and HEVs) depend strongly on their energy storage system. Advanced batteries such as lithium-ion (Li-ion) polymer batteries are quite viable options for storing energy in EVs and HEVs. In addition, thermal management is essential for achieving the desired performance and life cycle from a particular battery. Therefore, to design a thermal management system, a designer must study the thermal characteristics of batteries. The thermal characteristics that are needed include the surface temperature distribution, heat flux, and the heat generation from batteries under various charge/discharge profiles. Therefore, in the first part of the research, surface temperature distribution from a lithium-ion pouch cell (20Ah capacity) is studied under different discharge rates of 1C, 2C, 3C, and 4C.
2015-04-14
Technical Paper
2015-01-1236
John Jaranson, Meraj Ahmed
This paper describes the design, prototyping, and validation approaches for interior subsystems of the Multi-Material Lightweight Vehicle (MMLV). Case studies are presented for two of the interior subsystems: the instrument panel/cross-car beam and the front seat structures. Both of these subsystems took advantage of the weight saving opportunities presented by carbon fiber reinforced composite materials. Analytical methodologies are detailed along with prototype build techniques for each. Design weight savings of 30% for the instrument panel/cross-car beam and 17% for the seat structures are achieved. Physical test results are presented that validate the design and the weight savings.
2015-04-14
Technical Paper
2015-01-1254
Daishi Takahashi, Koichi Nakata, Yasushi Yoshihara, Yukinori Ohta, Hiroyuki Nishiura
In recent years, enhancing the engine thermal efficiency is strongly required. The current gasoline engine for hybrid vehicles has Atkinson cycle with high expansion ratio and cooled exhaust gas recirculation (EGR) system. The technologies contribute to raise the brake engine thermal efficiency more than 38%. It will be required that the engine thermal efficiency exceeds 40% in the near future. To enhance the engine thermal efficiency, it is essential to improve the engine anti-knock quality and to decrease the engine cooling heat loss. Therefore the cooled EGR technologies, which lead to reduce engine heat cooling loss and improve the anti-knock quality, are focused on. This paper describes that the technologies for enhancing the engine combustion technology such as high tumble which leads to the engine thermal efficiency of 40%.
2015-04-14
Journal Article
2015-01-1263
Kenichiro Ikeya, Masanobu Takazawa, Taketo Yamada, Shinrak Park, Ryutaro Tagishi
Efforts were made to enhance the maximum thermal efficiency of an automotive gasoline engine in order to meet increasing demands for CO2 reduction around the world. The target break thermal efficiency was set as 45% under following conditions: engine speed of 2,000 rpm, stoichiometric air fuel ratio, with RON91 gasoline. This paper describes basic engine specifications that can achieve the target break thermal efficiency with test result of a single-cylinder engine, and also discusses the issues for application to multi-cylinder engines. Using a high mechanical compression ratio is an effective means of enhancing the thermal efficiency. The thermal efficiency of a conventional engine peaks around a compression ratio of 15, and increasing the compression ratio above this level reduces the thermal efficiency. This is because the shape of the combustion chamber of a conventional engine impedes flame propagation when the compression ratio is increased.
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