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Viewing 121 to 150 of 8586
2017-03-28
Journal Article
2017-01-0266
Shervin Shoai Naini, Junkui (Allen) Huang, Richard Miller, John R. Wagner, Denise Rizzo, Scott Shurin, Katherine Sebeck
Designing an efficient cooling system with low power consumption is of high interest in the automotive engineering community. Heat generated due to the propulsion system and the on-board electronics in ground vehicles must be dissipated to avoid exceeding component temperature limits. In addition, proper thermal management will offer improved system durability and efficiency while providing a flexible, modular, and reduced weight structure. Traditional cooling systems are effective but they typically require high energy consumption which provides motivation for a paradigm shift. This study will examine the integration of passive heat rejection pathways in ground vehicle cooling systems using a “thermal bus”. Potential solutions include heat pipes and composite fibers with high thermal properties and light weight properties to move heat from the source to ambient surroundings.
2017-03-28
Journal Article
2017-01-0388
Haeyoon Jung, MiYeon Song, Sanghak Kim
Abstract CO2 emission is more serious in recent years and automobile manufacturers are interested in developing technologies to reduce CO2 emissions. Among various environmental-technologies, the use of solar roof as an electric energy source has been studied extensively. For example, in order to reduce the cabin ambient temperature, automotive manufacturers offer the option of mounting a solar cell on the roof of the vehicle [1]. In this paper, we introduce the semi-transparent solar cell mounted on a curved roof glass and we propose a solar energy management system to efficiently integrate the electricity generated from the solar roof into internal combustion engine (ICE) vehicles. In order to achieve a high efficiency solar system in different driving, we improve the usable power other than peak power of solar roof. Peak power or rated power is measured power (W) in standard test condition (@ 25°C, light intensity of 1000W/m2(=1Sun)).
2017-03-28
Journal Article
2017-01-1305
Yucheng Liu, Jeremy Batte, Zachary Collins, Jennifer Bateman, John Atkins, Madelyn Davis, David Salley, Cindy L. Bethel, John Ball, Christopher Archibald
Abstract A robot mining system was developed by the State Space Robotic undergraduate student design team from Mississippi State University (MSU) for the 2016 NASA Robotic Mining Competition. The mining robot was designed to traverse the Martian chaotic terrain, excavate a minimum of 10 kg of Martian regolith and deposit the regolith into a collector bin within 10 minutes as part of the competition. A Systems Engineering approach was followed in proceeding with this design project. The designed mining robot consisted of two major components: (1) mechanical system and (2) control system. This paper mainly focuses on the design and assessment process of the mechanical system but will also briefly mention the control system so as to evaluate the designed robotic system in its entirety. The final designed robot consisted of an aluminum frame driven by four motors and wheels. It utilized a scoop and lifting arm subsystem for collecting and depositing Martian regolith.
2017-03-28
Journal Article
2017-01-1302
Hyung In Yun, Jae Kyu Lee, Jae Hong Choi, MyoungKwon Je, Junhyuk Kim
Abstract A sliding door is one of the car door systems, which is generally applied to the vans. Compared with swing doors, a sliding door gives comfort to the passengers when they get in or out the car. With an increasing number of the family-scale activities, there followed a huge demand on the vans, which caused growing interests in the convenience technology of the sliding door system. A typical sliding door system has negative effects on the vehicle interior package and the operating effort. Since the door should move backward without touching the car body, the trajectory of the center rail should be a curve. The curve-shaped center rail infiltrates not only the passenger shoulder room, but also the opening flange curve, which results in the interior package loss. Moreover, as the passenger pulls the door outside handle along the normal direction of the door outer skin, the curved rail causes the opening effort loss.
2017-03-28
Technical Paper
2017-01-0152
Gang Liu, Zheng Zhao, Hao Guan, Chunhui Zhang, Dingwei Gao, Yongwei Cao
Abstract Advanced technology of thermal management is an effective method to reduce fuel consumption. There are several different technologies for coolant control, for example, electric water pump, split cooling and coolant control module. Through 1D thermal management simulation, coolant control module was chose for the test due to the best benefit for fuel consumption under NEDC cycle. 1D thermal management simulation model includes vehicle, cooling system, lubrication system and detailed engine model with all friction components. Coolant control module is designed to fix on 2.0L turbocharger GDI gasoline and to control 5 coolant ways, including radiator, by-pass, engine oil cooler, cabin heater and transmission oil cooler. The prototype is designed and made. The function and strategy is verified on designed test-bed. The vehicle with coolant control module is running under NEDC cycle.
2017-03-28
Journal Article
2017-01-1520
Teddy Hobeika, Peter Gullberg, Simone Sebben, Lennart Lofdahl
Abstract Quantification of heat exchanger performance in its operative environment is in many engineering applications an essential task, and the air flow rate through the heat exchanger core is an important optimizing parameter. This paper explores an alternative method for quantifying the air flow rate through compact heat exchangers positioned in the underhood of a passenger car. Unlike conventional methods, typically relying on measurements of direct flow characteristics at discrete probe locations, the proposed method is based on the use of load-cells for direct measurement of the total force acting on the heat exchanger. The air flow rate is then calculated from the force measurement. A direct comparison with a conventional pressure based method is presented as both methods are applied on a passenger car’s radiator tested in a full scale wind tunnel using six different grill configurations.
2017-03-28
Journal Article
2017-01-1215
Peter Haussmann, Joachim Melbert
Abstract Battery safety is the most critical requirement for the energy storage systems in hybrid and electric vehicles. The allowable battery temperature is limited with respect to the battery chemistry in order to avoid the risk of thermal runaway. Battery temperature monitoring is already implemented in electric vehicles, however only cell surface temperature can be measured at reasonable cost using conventional sensors. The internal cell temperature may exceed the surface temperature significantly at high current due to the finite internal electrical and thermal cell resistance. In this work, a novel approach for internal cell temperature measurement is proposed applying on board impedance spectroscopy. The method considers the temperature coefficient of the complex internal cell impedance. It can be observed by current and voltage measurements as usually performed by standard battery management systems.
2017-03-28
Journal Article
2017-01-1213
Yilin Yin, Zhong Zheng, Song-Yul Choe
Abstract Analysis of thermal behavior of Lithium ion battery is one of crucial issues to ensure a safe and durable operation. Temperature is the physical quantity that is widely used for analysis, but limited for accurate investigations of behavior of heat generation of battery because of sensitivities affected by heat transfer in experiments. Calorimeter available commercially is widely used to measure the heat generation of battery, but does not follow required dynamics because of a relatively large thermal time constant given by cavity and a limited heat transfer capability. In this paper, we proposed a highly dynamic calorimeter that was constructed using two thermoelectric devices (TEMs). For the design of the calorimeter and its calibration, a printed circuit board (PCB) with the same size as the battery was used as a dummy load to generate controlled heat.
2017-03-28
Journal Article
2017-01-0130
Phillip Bonkoski, Amey Y. Karnik, Adrian Fuxman
Abstract Control of vehicle powertrain thermal management systems is becoming more challenging as the number of components is growing, and as a result, advanced control methods are being investigated. Model predictive control (MPC) is particularly interesting in this application because it provides a suitable framework to manage actuator and temperature constraints, and can potentially leverage preview information if available in the future. In previous SAE publications (2015-01-0336 and 2016-01-0215), a robust MPC control formulation was proposed, and both simulation and powertrain thermal lab test results were provided. In this work, we discuss the controller deployment in a vehicle; where controller validation is done through road driving and on a wind tunnel chassis dynamometer. This paper discusses challenges of linear MPC implementation related to nonlinearities in this over-actuated thermal system.
2017-03-28
Journal Article
2017-01-0625
Yen-Chung Liu, Brian Sangeorzan, Alex Alkidas
Abstract The purpose of this research was to measure and correlate the area-average heat transfer coefficients for free, circular upward-impinging oil-jets onto two automotive pistons having different undercrown shapes and different diameters. For the piston heat transfer studies, two empirical area-average Nusselt number correlations were developed. One was based on the whole piston undercrown surface area with the Nusselt number based on the nozzle diameter, and the other was based on the oil-jet impingement area with the Nusselt number based on the oil-jet effective impingement diameter. The correlations can predict the 95% and 94% of the experimental measurements within 30% error, respectively. The first correlation is simpler to use and can be employed for cases in which the oil jet wets the whole piston undercrown. The latter may be more useful for larger pistons or higher Prandtl number conditions in which the oil jet wets only a portion of the undercrown.
2017-03-28
Journal Article
2017-01-0622
Sury Janarthanam, Sarav Paramasivam, Patrick Maguire, James Gebbie, Douglas Hughes
Abstract Hybrid Electric Vehicles (HEV) utilize a High Voltage (HV) battery pack to improve fuel economy by maximizing the capture of vehicle kinetic energy for reuse. Consequently, these HV battery packs experience frequent and rapid charge-discharge cycles. The heat generated during these cycles must be managed effectively to maintain battery cell performance and cell life. The HV battery pack cooling system must keep the HV battery pack temperature below a design target value and maintain a uniform temperature across all of the cells in the HV battery pack. Herein, the authors discuss some of the design points of the air cooled HV battery packs in Ford Motor Company’s current model C-Max and Fusion HEVs. In these vehicles, the flow of battery cooling air was required to not only provide effective cooling of the battery cells, but to simultaneously cool a direct current high voltage to low voltage (DC-DC) converter module.
2017-03-28
Journal Article
2017-01-0722
Pablo Olmeda, Jaime Martin, Antonio Garcia, David Villalta, Alok Warey, Vicent Domenech
Abstract Growing awareness about CO2 emissions and their environmental implications are leading to an increase in the importance of thermal efficiency as criteria to design internal combustion engines (ICE). Heat transfer to the combustion chamber walls contributes to a decrease in the indicated efficiency. A strategy explored in this study to mitigate this efficiency loss is to promote low swirl conditions in the combustion chamber by using low swirl ratios. A decrease in swirl ratio leads to a reduction in heat transfer, but unfortunately, it can also lead to worsening of combustion development and a decrease in the gross indicated efficiency. Moreover, pumping work plays also an important role due to the effect of reduced intake restriction to generate the swirl motion. Current research evaluates the effect of a dedicated injection strategy to enhance combustion process when low swirl is used.
2017-03-28
Technical Paper
2017-01-0328
Yunkai Gao, Genhai Wang, Jingpeng Han
Abstract The multi-body dynamics simulation and physical iteration were carried out based on the 4-channel road simulation bench, the solution of fatigue test bench which was suitable for cab with frame and suspension was designed. Large load and displacement above the suspension can be loaded on the test bench, and the same weak position of cab exposed on the road test can be assessed well on the fatigue test bench. The effectiveness of the bench test solution was verified though comparative study. And it has important reference for the same type of cab assembly with suspension in the fatigue bench test. According to the durability specifications of cab assembly, a multi-body dynamics model with a satisfactory accuracy was built. And the fixture check and virtual iteration analysis were used to verify the effectiveness of the solution. According to the road load signal analysis and multi-body dynamics analysis results, the test bench with linear guide and spherical joint was built.
2017-03-28
Journal Article
2017-01-0120
Yoichiro Kawamoto, Gota Ogata, Zhiwei Shan
Abstract This study reports on a new generation ECS (Ejector Cycle System) which includes a highly efficient ejector and a novel system configuration. The ejector is working as a fluid jet pump that recovers expansion energy which is wasted in the conventional refrigeration cycle decompression process, and converts the recovered expansion energy into pressure energy and raises the compressor suction pressure. Consequently, the ejector system can reduce power consumption of the compressor by using the above mentioned pressure-rising effect and improve energy efficiency of the refrigeration cycle. The ejector consists of a nozzle, a suction section, a mixing section and a diffuser. The objective of this study is to improve actual fuel economy of all vehicles by ejector technology. The previous generation ECS was reported in 2012 SAE World Congress1. Now, a new generation ECS has been successfully developed and released in the market for Mobile Air Conditioning systems as of 2013.
2017-03-28
Technical Paper
2017-01-0188
Yoichiro Higuchi, Hiroyuki Kobayashi, Zhiwei Shan, Mikiharu Kuwahara, Yoshiharu Endo, Yuha Nakajima
Abstract As vehicle emission regulations become increasingly rigorous, the automotive industry is accelerating the development of electrified vehicle platforms such as Battery Electric Vehicles (BEV) and Plug-in Hybrid Electric Vehicles (PHEV). Since the available waste heat from these vehicles is limited, additional heat sources such as electric heaters are needed for cabin heating operation. The use of a heat pump system is one of the solutions to improve EV driving range at cold ambient conditions. In this study, an efficient gas-injection heat pump system has been developed, which achieves high cabin heating performance at low ambient temperature and dehumidification operation without the assistance of electric heaters in ’17 model year Prius Prime.
2017-03-28
Technical Paper
2017-01-0515
Thomas De Cuyper, Stijn Broekaert, Duc-Khanh Nguyen, Kam Chana, Michel De Paepe, Sebastian Verhelst
Abstract Engine optimization requires a good understanding of the in-cylinder heat transfer since it affects the power output, engine efficiency and emissions of the engine. However little is known about the convective heat transfer inside the combustion chamber due to its complexity. To aid the understanding of the heat transfer phenomena in a Spark Ignition (SI) engine, accurate measurements of the local instantaneous heat flux are wanted. An improved understanding will lead to better heat transfer modelling, which will improve the accuracy of current simulation software. In this research, prototype thin film gauge (TFG) heat flux sensors are used to capture the transient in-cylinder heat flux within a Cooperative Fuel Research (CFR) engine. A two-zone temperature model is linked with the heat flux data. This allows the distinction between the convection coefficient in the unburned and burned zone.
2017-03-28
Journal Article
2017-01-1046
Christian Binder, Fahed Abou Nada, Mattias Richter, Andreas Cronhjort, Daniel Norling
Abstract Diesel engine manufacturers strive towards further efficiency improvements. Thus, reducing in-cylinder heat losses is becoming increasingly important. Understanding how location, thermal insulation, and engine operating conditions affect the heat transfer to the combustion chamber walls is fundamental for the future reduction of in-cylinder heat losses. This study investigates the effect of a 1mm-thick plasma-sprayed yttria-stabilized zirconia (YSZ) coating on a piston. Such a coated piston and a similar steel piston are compared to each other based on experimental data for the heat release, the heat transfer rate to the oil in the piston cooling gallery, the local instantaneous surface temperature, and the local instantaneous surface heat flux. The surface temperature was measured for different crank angle positions using phosphor thermometry.
2017-03-14
Journal Article
2017-01-9276
Joseph K. Ausserer, Marc D. Polanka, Jacob A. Baranski, Keith D. Grinstead, Paul J. Litke
Abstract The rapid expansion of the market for remotely piloted aircraft (RPA) includes a particular interest in 10-25 kg vehicles for monitoring, surveillance, and reconnaissance. Power-plant options for these aircraft are often 10-100 cm3 internal combustion engines. Both power and fuel conversion efficiency decrease with increasing rapidity in the aforementioned size range. Fuel conversion efficiency decreases from ∼30% for conventional-scale engines (>100 cm3 displacement) to <5% for micro glow-fuel engines (<10 cm3 displacement), while brake mean effective pressure decreases from >10 bar (>100 cm3) to <4 bar (<10 cm3). Based on research documented in the literature, the losses responsible for the increase in the rate of decreasing performance cannot be clearly defined.
2017-01-10
Technical Paper
2017-26-0262
Neelakandan Kandasamy, Koundinya Narasimha Kota, Prasad Joshi
Abstract The structure of a vehicle is capable of absorbing a significant amount of heat when exposed to hot climate conditions. 50-70% of this heat penetrates through the glazing and raises both the internal cabin air temperature and the interior trim surface temperature. When driving away, the air conditioning system has to be capable of removing this heat in a timely manner, such that the occupant’s time to comfort will be achieved in an acceptable period [1]. When we reduce the amount of heat absorbed, the discomfort in the cabin can be reduced. A 1D/3D based integrated computational methodology is developed to evaluate the impact of vehicle orientation on cabin climate control system performance and human comfort in this paper. Additionally, effects of glazing material and blinds opening/closing are analyzed to access the occupant thermal comfort during initial and final time AC pull down test.
2017-01-10
Technical Paper
2017-26-0237
Bhupesh Agrawal, Mohit Varma, Chandrashekhar Sewatkar
Abstract High temperatures in the surface mounted permanent magnet (SMPM) synchronous motor adversely affect the power output at the motor shaft. Temperature rise may lead to winding insulation failure, permanent demagnetization of magnets and encoder electronics failure. Prediction and management of temperatures at different locations in the motor should be done right at the design stage to avoid such failures in the motor. The present work is focused on the creation of Lumped Parameter Thermal Network (LPTN) and CFD models of SMPM synchronous motor to predict the temperature distribution in the motor parts. LPTN models were created in Motor-CAD and Simulink which are suitable for parameter sensitivity analysis and getting quick results. Air is assumed to be a cooling medium to extract heat from the outer surface of motor. CFD models were useful in providing elaborate temperature distribution and also locating the hot-spots. Correlation models by both the methods, viz.
2017-01-10
Technical Paper
2017-26-0029
Shubham Saxena, Mudassir Ahmed
Abstract Higher fuel economy of the vehicle is a critical concern in automobile industry. Traditional internal combustion (IC) engines waste a large portion of the available fuel energy as heat loss via exhaust gas. This proposal aims at recovering the available exhaust heat of the IC engines using stirling engine (SE) as an add-on device. SE is a type of cyclic heat engine which operates by compression and expansion of the working fluid, at different temperature levels resulting in a conversion of the heat energy into mechanical work. A thermodynamic analysis is performed on the chosen beta SE rhombic drive configuration with different combinations of design parameters like working fluid mass, total dead volume, thermal resistance, and hot side and cold side temperatures. A regenerator temperature model is developed to account for first law consistency in the regenerator section of SE, along with heat transfer in accordance with mass flow within the regenerator.
2017-01-10
Technical Paper
2017-26-0087
Prasad B Warule, Vaibhav V Jadhav
Abstract Hybridization of vehicle drive train is an important step to increase energy security, reduce crude oil import, improvement of air quality and GHG reduction. Heavy traffic congestion poses a great challenge in improvement of fuel economy. Nowadays urban climatic condition forces the passenger to keep air-conditioning (AC) on; thus further decreasing the fuel economy. In a typical urban drive; the vehicle commutes with low speed forcing IC Engine to run in its low efficiency operational points. Further it is characterized by frequent start-stop and crawling. It has been observed that the power consumption for AC is comparable to that required for the vehicle propulsion. Hence the AC on condition with propelling vehicle demands higher power from engine creating a challenge for fuel economy improvement.
2017-01-10
Technical Paper
2017-26-0098
Riaz Ahamed, Koorma Rao Vavilapalli, Clement Jones, V P Abhijith
Abstract Major decision driving constraints in the automobile sector is space and cost. With the advent of electric vehicles, these constraints apply for electric drive motor also. For applications involving neighborhood electric vehicles (NEV), the challenges become manifold with target cost of complete drivetrain system, including motor, controller & transmission, being very low. This and application of low cost axle mount drive systems prohibits usage of liquid cooled systems. In this scenario, ways to improve thermal performance of motor can be - to reduce heat generation, increase heat conduction and to increase heat rejection so that temperature of winding is kept under thermal limit of insulation used. Major area of thermal hotspots in the motor is at the end windings where direct conductive path to the housing is less. In this paper, thermal performance of the motor is improved by introducing vacuum encapsulation at the end winding thereby increasing net heat conduction.
2017-01-10
Technical Paper
2017-26-0150
Abhijeet Chothave, Yashwant Mohite, Vinay Poal, Phaneendra Pamarthi
Abstract In present day passenger cars, Mobile Air Conditioning (MAC) system is one of the essential features due to rise in overall ambient temperatures and comfort expectation of customers. During the development of MAC system, the focus is on cooling capacity of system for maintaining in-cabin temperatures. However, parameters like solar radiation, air velocities at occupant, relative humidity, metabolic rate and clothing of occupants also influence occupant’s thermal comfort and normally not considered in design of the MAC system. Subjective method is used to evaluate thermal comfort inside vehicle cabin which depends mainly on human psychology. To better understand the effect and minimize the human psychological factors a large sample of people are required. That process of evaluating the comfort inside the vehicle cabin is not only time consuming but also impractical.
2017-01-10
Technical Paper
2017-26-0370
G. Meenakshi, Nishit Jain, Sandeep Mandal
Abstract Automobile industry is shifting its focus from conventional fuel vehicles to NexGen vehicles. The NexGen vehicles have electrical components to propel the vehicle apart from mechanical system. These vehicles have a goal of achieving better fuel efficiency along with reduced emissions making it customer as well as environment friendly. Idle start-stop is a key feature of NexGen vehicles, where, the Engine ECU switches to engine stop mode while idling to cut the fuel consumption and increase fuel efficiency. Engine restarts when there is an input from driver to run the vehicle. There is always a clash between the Engine ECU and automatic climate control unit (Auto-AC) either to enter idle stop mode for better fuel efficiency or inhibit idle stop mode to keep the compressor running for driver comfort. This clash can be resolved in two ways: 1 Hardware change and,2 Software change Hardware change leads to increase in cost, validation effort and time.
2017-01-10
Technical Paper
2017-26-0180
Swaminathan Ramaswamy, Christophe Schorsch, Mario Kolar
Abstract Automotive OEMs are adapting various “green” technologies to meet the upcoming and anticipated regulations for reducing direct and indirect GHG emissions equivalent to CO2. Using compact devices and lightweight components on the aggregates, OEMs get the benefit of carbon credits towards their contribution in reducing CO2 emissions. With regards to the HVAC systems, enhancements such as ultra-low permeation hose assemblies and adoption of low GWP refrigerant have shown promising results in reducing the direct GHG emissions by controlling refrigerant permeation & indirect GHG emissions by using compact and high efficiency compressors, compact heat exchangers, and other technologies that contribute to weight reduction and ultimately impact CO2 emissions. Traditional AC lines are routed/installed in space that accommodates the relative movement between the engine and chassis by connecting the various parts.
2017-01-10
Journal Article
2017-26-0364
Igor Gritsuk, Vladimir Volkov, Vasyl Mateichyk, Yurii Gutarevych, Mykola Tsiuman, Nataliia Goridko
Abstract The article suggests the results of experimental and theoretical studies of the engine heating system with a phase-transitional thermal accumulator when the vehicle is in motion in a driving cycle. The aim of the study is to evaluate the efficiency of the vehicle heating system within thermal accumulator and catalytic converter under operating conditions. The peculiarity of the presented system is that it uses thermal energy of exhaust gases to accumulate energy during engine operation. The article describes the methodology to evaluate vehicle fuel consumption and emission in the driving cycle according to the UNECE Regulation № 83-05. The methodology takes into account the environmental parameters, road conditions, the design parameters of the vehicle, the modes of its motion, thermal state of the engine cooling system and the catalytic converter.
2017-01-10
Journal Article
2017-26-0073
B Ashok, K Nantha Gopal, Thundil Karuppa Raj Rajagopal, Sushrut Alagiasingam, Suryakumar Appu, Aravind Murugan
Abstract With the alarming increase in vehicular population, there is depletion of fossil fuel availability. Hence to overcome the difficulties, alternative fuels are tested and used in parts of the world. One of the difficulties with usage of alternate fuels is their high viscosity in comparison to fossil fuels. To overcome this, preheating of biofuel is a good option as it makes the fuel less viscous. In our research, we have used a helical coil heat exchanger to preheat the inlet fuel using the engine’s exhaust gas, making the system more sustainable since no external energy is used. In order to evaluate the effectiveness of preheating device a simulation study has been carried for the ethanol based biofuels. For simulation work, a set of boundary conditions has been arrived based on the experimental analysis. The results from the experiment such as velocity of air and fuel inlet were utilized as input for simulation work.
2016-11-08
Technical Paper
2016-32-0008
Balagovind Nandakumar Kartha, Srikanth Vijaykumar, Pramod Reddemreddy
Abstract Today, nations are in the path of low-emission transformation mandating stricter emission norms with periodic revisions. With the expected introduction of Bharath Stage VI (BS VI) for two wheelers in India by 2020, limitation in primary pollutants namely - Carbon Monoxide (CO), Total Hydro-Carbons (THC) and Nitrogen Oxides (NOx) are reduced by 50%, 75% and 85% respectively in comparison to the existing Bharath Stage IV. The original equipment manufacturers (OEMs) are identifying measures to improve the overall efficiency and raw emissions from the engine through strategies like multi-spark configurations, improved charge induction concepts, liquid cooling, lean combustion etc. With end user demands for performance, low end torque, high power to displacement ratio, quick acceleration and fuel efficiency, the balance with the emission regulation is expected to be challenging.
2016-11-08
Technical Paper
2016-32-0077
Roland Baar, Valerius Boxberger, Maike Sophie Gern
Abstract Two-cylinder engines not only have special demands concerning uniformity and dynamics of oscillating masses and firing order, but also place very different demands on the turbocharger. With two-cylinder engines, the pulsating influence grows and changes the operation of the turbine. In this paper different boosting technologies are compared in small engine applications. Besides turbochargers the potentials and limits of superchargers and electric chargers are compared as well as their combinations. These technologies show differences concerning power supply, operation range and efficiency, and these effects have different implications in small engines. The efficiency of a turbo compressor, for example decreases, rapidly for small dimensions. Results from experiments and engine process simulations are shown based on a two-cylinder engine of 0.8l displacement. The operating condition of a turbocharger turbine in a two-cylinder engine is very specific due to exhaust pulsations.
Viewing 121 to 150 of 8586