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Technical Paper
2014-10-13
Ramadhas Arumugam Sakunthalai, Hongming Xu, Dai Liu, Jianyi Tian, Miroslaw Wyszynski, Jakub Piaszyk
The cold start performance of diesel engines has been receiving more attention when the European Commission emission regulations directed to include the cold start emissions in the legislative emission driving cycles. The cold start performance of diesel engines is influenced by the ambient conditions, engine design, fuel, lubricant and engine operating conditions. The present research work investigates the effect of the cold ambient conditions on the engine idle speed stability and the exhaust emissions (gaseous and particle emissions) from the diesel engine during the cold start and followed by idle conditions. The engine startability and idling tests were carried out on the diesel engine in the cold cell at the different ambient temperatures ranges between +20 ºC and -20 ºC. The higher fuel consumption and peak speed observed at very cold ambient temperatures have been compared to those at ambient conditions. The exhaust emissions of the engine were higher at cold start and then it started decreasing during idle.
Technical Paper
2014-10-13
Nicolas Arnault, Guy Monsallier
Cold weather is a challenge for compression ignition engines. As Diesel fuel creates wax crystals and gel when temperature goes down enough (sometimes just below 0°C), it comes to plug the fuel filter and the fuel injection system, leading to undesirable effects like loss of power, engine stall after start or even engine not starting at all. Side effects like fuel feeding pump durability can also be linked to it. Moreover, it has been shown that BioDiesel, and especially FAME coming from Palm, Tallow or Used Kitchen Oil has negative impacts on vehicle cold flow operability. Literature has even identified the key fuel components which impact the cold flow properties. Fuel cold flow properties can be improved through additives, which can be already included in the fuel at the pump, or manually added by the driver. But, obviously this cannot be easily controlled on the field and car manufacturers cannot handle in advanced where the fuel fill-up will be done, nor the quality of the fuel fed in the vehicle tank.
Technical Paper
2014-10-13
Antonino La Rocca, David MacMillan, Paul Shayler, Michael Murphy, Ian Pegg
Cold idle operation of a modern design light duty diesel engine and the effect of multiple pilot injections on stability were investigated. Magnitude and cycle-to-cycle variation of indicated parameter have been used as key indicators of cold idle performance. The utility of different injection strategies, up to three pilot injections before a main, is investigated. The investigation was initially carried out experimentally at 1000rpm, a speed representative of idle conditions, and at -20ºC. Benefits of mixture preparation were initially explored by a heat release analysis performed for each case. A CFD investigation was then used to visualise the effect of multiple pilots on in-cylinder mixture distribution, with particular emphasis on how the injection patterns affect the mixture distribution in the proximity of the glow plug. Kiva 3v was used to model the combustion system and fuel injections. A 60º mesh was used taking advantage of rotational symmetry. Combustion system and injector arrangements mimic the HPCR diesel engine used in the experimental investigation.
Technical Paper
2014-10-13
Xianjing Li, Liguang Li
Gasoline Direct Injection (GDI) engines have attracted interest as automotive powerplants because of their potential advantages in down-sizing, fuel efficiency and in emissions reduction. In modern gasoline combustion concepts the application of direct injection combined with stratification is one of the most promising strategies. However, GDI engines suffer from elevated unburned hydrocarbon (HC) emissions at the start up process, which are sometimes worsened by misfires and partial burns. Moreover, as the engine is cranked to idle speed quickly in HEV mode, the transients are more dramatically than that in traditional vehicle, which are harmful to combustion and emission performance. This paper concerned about the GDI engine performances for ISG HEVs during the start-up process. A servo motor was connected directly to the engine output shaft to simulate the ISG. Based on the test system, cycle-controlled of the fuel injection mass, fuel injection timing, ignition timing and so on, can be obtained, as well as the cycle-resolved measurement of the HC concentrations and NO emissions.
Technical Paper
2014-10-13
Dai Liu, Hongming Xu, Ramadhas Arumugam Sakunthalai, Jianyi Tian
Cold start is a critical operating condition for diesel engines because of the resultant pollutant emissions produced by the unstable combustion at lower temperatures. In this research work, a light-duty, turbocharged diesel engine equipped with a common rail injection system was tested on a transient engine testing bed for an investigation of the starting process in terms of engine performance and emissions. The engine (including engine coolant, engine oil and fuel) was soaked in a cold cell at -7°C for at least 8 hours before starting of the test. The engine operating parameters such as engine speed, air/fuel ratio and EGR rate were recorded during the tests. Pollutant emissions (HC, NOx and particles both in mode of nucleation and accumulation) were measured before and after DOC. The results showed that conversion efficiency of NOx was higher during acceleration period at -7°C start than the case at 20°C start. The reduction of NOx and THC by DOC was less during idle period at -7°C cold start.
Technical Paper
2014-10-13
Cheng Tan, Hongming Xu, He Ma, Jianyi Tian, Akbar Ghafourian
Automotive engines especially turbocharged diesel engines produce higher level of emissions during transient operation than in steady state. Therefore, the study of engine transients has received increasing attention for meeting the new emission legislations. In order to improve understanding of the engine transients and develop advanced technologies to reduce the transient emissions, the engine researchers require accurate data acquisition and appropriate post-processing techniques which are capable of dealing with noise and synchronization issues. The objective of this study is to develop a methodology for the measurement and processing of data during transient engine tests concerning the noise in time-resolved data during the transient which requires proper filtering. A common practice in engine tests is ensemble averaging the data of a number of cycles for the steady state experiments but this method is not suitable for the transient cases. In this study, four alternative automated methods were implemented on in-cylinder pressure data of each individual cycle to compare and analyze the suitability of combustion diagnostic.
Technical Paper
2014-10-13
Krzysztof Jan Siczek
Nowadays microbes like bacteria are used to wring out electrical energy trapped in wastewater. Such bacterial batteries use oxygen at the cathode to soak up the harvested electrons. Oxygen is used because of its efficiency during collecting electrons. Unfortunately such mini power plants can be treacherous and sensitive to leak of oxygen and microbes. The oxygen can bubble over to the anode and the bacteria can migrate closer to the cathode to swipe the gas for their own energy production. They can also case risks a short circuit. In the case of such battery it is a real problem the control of gas flow and behaviour. To prevent spillover between electrodes in such batteries, engineers use the complex membrane barriers should be used. Replacing of bubbling oxygen with solid silver oxide that gobbles up electrons allows creating rechargeable bacterial battery. For both fuel cell and microbe-based battery it is needed a place to send electrons, but putting oxygen in there is a real problem.
Technical Paper
2014-10-13
Balaji Bandaru, L. Navaneetha Rao, P. S. S. Babu, Krishna Kumar Varathan, J. Balaji
The present work describes an approach for simulation of on-road-driving cycles (duty cycles) in transient engine testbed to predict the fuel economy for different vehicles from ICV to HCV. The driving cycles investigated in the current study are generated from the typical experimental data measured from instrumented vehicles in real world traffic conditions ranging from different cities, highways and village roads in India. The measured driving cycle data is analyzed using MATLAB programing, and then sub-divided into several zones depend on the time of operation over the engine operating area. Later, the engine driving cycle data was corrected in terms of speed and torque before simulating in engine testbed, which is essential for minimizing dynamometer influence on the fuel consumption. The power consumed by auxiliary equipment and other losses were considered in the study. The main objective of the work is to develop a procedure to estimate the likely performance, fuel economy and emissions of an upcoming/under development engine or vehicle, by a given drive cycle simulation, without having to go through the costly route of building the vehicle.
Technical Paper
2014-10-13
Jianyi Tian, Hongming Xu, Ramadhas Arumugam Sakunthalai, Dai Liu, Cheng Tan, Akbar Ghafourian
Engine transients have attracted high attentions from researchers due to their high frequency of occurrence during daily vehicle driving. More emissions are expected compared to steady states as a result of the turbo-lag problem. Ambient temperature has a significant influence on engine transients especially at the start. The effects of ambient temperature on engine-out emissions under the New European Driving Cycle (NEDC) were investigated in this study. The transient engine tests were carried out on a modern 3.0 L, V6 turbocharged common rail diesel engine fuelled with winter diesel in the cold cell at the different ambient temperatures ranges between +20 and -7 ºC. The engine including, fuel, coolant, combustion air and lubricating oil were soaked and maintained at the desired test temperatures during the whole transient tests. Instantaneous engine performances including torque and speed, gaseous emissions such as CO, HC and NOx, and particle emissions for its number and size distribution were analysed during each transient test at different ambient conditions.
Technical Paper
2014-09-30
Sanket Pawar
Off-road commercial vehicles many times have to work at remote areas in poor working conditions like reduced visibility due to fog, snow, inadequate ambient lighting, dust etc..They may not have any access to emergency facilities in such places. Challenging geographical terrains and adverse weather conditions makes the situation worse. The combination of both can further degrade working conditions. The operator may need to either work or guide his vehicle through tight places or in hilly areas having such conditions. That imposes many challenges to operator in terms of efficiency & safety of both operator & vehicle. In an effort to increase productivity and efficiency operator may miss to look at safety aspects consequently, leading to accidents that can incur heavy losses due to damages to vehicle further delaying the work. It can even lead to a life threatening emergency in some cases. On the other hand, decrease in efficiency results in increased cost of operation due to unnecessary wastage of fuel & delays in getting the work done.
Technical Paper
2014-09-16
Mike Boost
Rechargeable lithium batteries are essentially ubiquitous in our daily lives and in virtually every industry from pocket key fobs to billion dollar space programs, in benign as well as extreme environments. Cell production in 2012 was estimated at 4.4 billion cells and expected to double by 2016. However within civil aviation, lithium batteries are still in the early stages of deployment. The general consensus within the industry is that the use of lithium batteries within civil aviation will increase substantially in the coming years. Within the past decade the use of rechargeable lithium batteries has been certified on several platforms including Airbus, Cessna and Boeing. Airframe manufacturers are highly focused on the potential for the lithium technology to reduce the weight and thus increase range for their aircraft. However, there are numerous considerations within the lithium battery design that must be addressed to achieve optimal safety, more specifically lithium cell determination and electronic design.
Technical Paper
2014-09-16
Karen Davies, Patrick Norman, Catherine Jones, Stuart Galloway, Graeme Burt
Abstract Turboelectric Distributed Propulsion (TeDP) is actively being investigated as a means of providing thrust in future generations of aircraft. In response to the lack of published work regarding the system-level fault behaviour of a fully superconducting network, this paper presents key points from a two stage Failure Modes and Effects Analysis (FMEA) of a representative TeDP network. The first stage FMEA examines the qualitative behaviour of various network failure modes and considers the subsequent effects on the operation of the remainder of the network, enabling the identification of key variables influencing the fault response of the network. For the second stage FMEA, the paper focuses on the characterisation of the rate at which electrical faults develop within a TeDP network. The impact of system quench and associated rise in network resistance as well as network parameters such as network voltage and pre-fault current, on the resulting fault profile are also examined using a range of sensitivity studies.
Technical Paper
2014-09-16
Gregory J. Moore, Frank Puglia, Lawrence Myron, Stephen Lasher, Bob Doane, Joe Gnanaraj, Seth Cohen, Arthur Dobley, Ryan Lawrence, Rong Yan
For 70 years Yardney has been a leader in specialty battery and energy systems for military, space, avionics, weapon systems and undersea vehicles. Yardney has evolved since beginning in 1944 in New York City, to Pawcatuck, CT, and since 2013 resides in East Greenwich, RI. The chemistries provided in this time include silver-zinc, magnesium silver chloride, lithium thionyl-chloride, nickel zinc, lithium-ion (Li-ion) and several metal-air technologies. Yardney has made cells from 50 mAh for human implantables to 1000 Ah for submersible vehicles. In addition to battery systems, Yardney also pursues hybrid systems for ground, space, undersea and avionic applications. The beauty of hybrid systems, combining energy sources such as batteries, capacitors, fuel cells and solar, is that they can be used to optimize energy and power density, and with proper design lead to longevity of components and an overall cost savings. Where fuel cells can provide the most energy of these specified constituents on a large scale, at a smaller scale they come at a cost due to their inefficiencies and their bulk.
Technical Paper
2014-09-16
Steven David Angus Fletcher, Patrick Norman, Stuart Galloway, Graeme Burt
Abstract The development of the More-Electric Engine (MEE) concept will see an expansion in the power levels, functionality and criticality of electrical systems within engines. However, to date, these more critical electrical systems have not been accounted for in existing engine certification standards. To begin to address this gap, this paper conducts a review of current engine certification standards in order to determine how these standards will impact on the design requirements of More-Electric Engine (MEE) electrical system architectures. The paper focuses on determining two key architectural requirements: the number of individual failures an architecture can accommodate and still remain functional and the rate at which these failures are allowed to occur. The paper concludes by discussing how the derived failure rates begin to define a set of design requirements for MEE electrical architectures, considering various operating strategies, and demonstrates their application to example MEE electrical system architecture designs.
Technical Paper
2014-09-16
David Gras, Christophe Pautrel, Amir Fanaei, Gregory Thepaut, Maxime Chabert, Fabien Laplace, Gonzalo Picun
Abstract In this paper we present a set of integrated circuits specifically designed for high temperature power applications such as isolated power transistor drivers and high efficiency power supplies. The XTR26010 is the key circuit for the isolated power gate drive application. The XTR26010 circuit has been designed with a high focus in offering a robust, reliable and efficient solution for driving a large variety of high-temperature, high-voltage, and high-efficiency power transistors (SiC, GaN, Si) existing in the market. The XTR40010 is used for isolated data communication between a microcontroller or a PWM controller and the power driver (XTR26010). The isolated power transistor driver features a dual turn-on channel, a turn-off channel and a Miller Clamp channel with more than 3A peak current drive strength for each channel. The dV/dt immunity between XTR26010 and XTR40010 exceeds 50kV/μs. To demonstrate the performance and reliability at system level, a half-bridge driver test-board has been developed for driving SiC MOSFETs.
Technical Paper
2014-09-16
Shweta Sanjeev, Goutham Selvaraj, Patrick Franks, Kaushik Rajashekara
Abstract The transition towards More Electric Aircraft (MEA) architectures has challenges relating to integration of power electronics with the starter generator system for on-engine application. To efficiently operate the power electronics in the hostile engine environment at high switching frequency and for better thermal management, use of silicon carbide (SiC) power devices for a bi-directional power converter is examined. In this paper, development of a 50 kVA bi-directional converter operating at an ambient temperature of about 2000C is presented. The design and operation of the converter with details of control algorithm implementation and cooling chamber design are also discussed.
Technical Paper
2014-09-16
Fei Gao, Serhiy Bozhko, Greg Asher
Abstract Stability is a great concern for the Electrical Power System (EPS) in the More Electric Aircraft (MEA). It is known that tightly controlled power electronic converters and motor drives may behave as constant power loads (CPLs) which may produce oscillations and cause instability. The paper investigates the stability boundaries for dc multi-source EPS under different power sharing strategies. For each possible strategy the corresponding reduced-order models are derived. The impedance criterion is then applied to study the EPS stability margins and investigates how these margins are influenced by different parameters, such as main bus capacitance, generator/converter control dynamics, cabling arrangements etc. These results are also illustrated by the root contours of reduced-order EPS models. Theoretical results achieved in the paper are confirmed by the time-domain simulations.
Technical Paper
2014-09-16
Brian C. Raczkowski, Benjamin Loop, Jason Wells, Eric Walters, Oleg Wasynczuk, Sean Field, Jason Gousy
Abstract Future more electric aircraft (MEA) architectures that improve electrical power system's (EPS's) source and load utilization will require advance stability analysis capabilities. Systems are becoming more complex with bidirectional flows from power regeneration, multiple sources per channel and higher peak to average power ratios. Unknown load profiles with large transients complicate common stability analysis techniques. Advancements in analysis are critical for providing useful feedback to the system integrator and designers of multi-source, multi-load power systems. Overall, a framework for evaluating stability with large displacement events has been developed. Within this framework, voltage transient bounds are obtained by identifying the worst case load profile. The results can be used by system designers or integrators to provide specifications or limits to suppliers. Subsystem suppliers can test and evaluate their design prior to integration and hardware development. By identifying concerns during the design phase, a more streamlined approach to hardware development can save on rework, integration delays and cost.
Technical Paper
2014-09-16
Michael L. Zierolf, Thomas Brinson, Andrew Fleming
Abstract Recent emphasis on optimization of engine technologies with ancillary subsystems such as power and thermal management has created a need for integrated system modeling. These systems are coupled such that federated design methods may not lead to the most synergetic solution. Obtaining an optimal design is often contingent on developing an integrated model. Integrated models, however, can involve combining complex simulation platforms into a single system of systems, which can present many challenges. Model organization and configuration control become increasingly important when orchestrating various models into a single simulation. Additionally, it is important to understand such details as the interface between models and signal routing to ensure the integrated behavior is not contaminated or biased. This paper will present some key learnings for model integration to help alleviate some of the challenges with system-based modeling.
Technical Paper
2014-09-16
James Borg Bartolo, Chris Gerada
Abstract A 45kW, switched reluctance type, starter-generator, having a 1:4 constant power speed range has been designed as a possible candidate for a regional jet application. In the first section of this paper, a review of the major starter-generator topologies considered for the aerospace application is provided, highlighting the advantages of choosing the Switched reluctance topology for such a safety critical application. Following this, the required torque speed characteristic of the machine, along with the imposed physical constraints, in terms of cooling and outer dimensions, are also detailed. Section III provides a description of the Electromagnetic design, and challenges encountered in meeting both the low speed, peak torque node, at 8000rpm, and the high speed, high power node, at 32000rpm. The induced mechanical stresses in the rotor at such high speeds have also been evaluated and used as a material selection criterion for such a design as presented in section III. Section IV, describes the thermal model developed to estimate the radial temperature distribution within the machine, taking into account end winding phenomena and cooling fluid constraints.
Technical Paper
2014-09-16
Puvan Arumugam, Chris Gerada, Serhiy Bozhko, He Zhang, Weeramundage Fernando, Antonino La Rocca, Stephen Pickering
Abstract This paper describes a high-speed electrical machine for an aircraft starter-generator. A surface mounted permanent magnet machine is designed to have minimal rotor losses and a novel cooling system for the stator. An inner stator sleeve is adopted to allow for a flooded stator whilst minimizing rotor windage losses. Different slot-pole combinations are compared in view of attaining an optimal combination that provides minimum losses whilst satisfying the electromagnetic, mechanical and thermal constraints.
Technical Paper
2014-09-16
Javier Gazzarri, Nishant Shrivastava, Robyn Jackey, Craig Borghesani
Battery Management System (BMS) design is a complex task requiring sophisticated models that mimic the electrochemical behavior of the battery cell under a variety of operating conditions. Equivalent circuits are well-suited for this task because they offer a balance between fidelity and simulation speed, their parameters reflect direct experimental observations, and they are scalable. Scalability is particularly important at the real time simulation stage, where a model of the battery pack runs on a real-time simulator that is physically connected to the peripheral hardware in charge of monitoring and control. With modern battery systems comprising hundreds of cells, it is important to employ a modeling and simulation approach that is capable of handling numerous simultaneous instances of the basic unit cell while maintaining real time performance. In previous publications we presented a technique for the creation of a battery cell model that contains the electrochemical fingerprints of a battery cell based on equivalent circuit model fitting to experimental data.
Standard
2014-08-26
This ARP specifies the recommended methods of marking electrical wiring and harnesses to aid in the positioning/routing of electrical wiring, harnesses and cable assemblies.
Standard
2014-08-26
This SAE Recommended Practice identifies and defines requirements relating to the safe integration of the fuel cell system, the hydrogen fuel storage and handling systems (as defined and specified in SAE J2579) and high voltage electrical systems into the overall Fuel Cell Vehicle. The document may also be applied to hydrogen vehicles with internal combustion engines. This document relates to the overall design, construction, operation and maintenance of fuel cell vehicles. 1.1 Purpose The purpose of this document is to provide mechanical and electrical system safety guidelines, safety criteria and methodologies that should be considered when designing fuel cell vehicles for use on public roads. 1.2 Field of Application This document is applicable to fuel cell vehicles designed for use on public roads.
Standard
2014-08-20
This SAE Aerospace Information Report (AIR) defines the areas where incompatibility may exist between the selected wire and the electrical connector in which it is terminated and how to design for compatibility. Refer to ARP914 for a glossary of connection terms.
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