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Viewing 1 to 30 of 12576
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
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
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
Jianyi Tian, Hongming Xu, Ramadhas Arumugam Sakunthalai, Dai Liu, Cheng Tan
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
2014-10-13
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
Chunshan Li, Guoying Chen, Changfu Zong
This paper presents a fault-tolerant control (FTC) approach for four-wheel independently driven and steered (4WID/4WIS) electric vehicles. An adaptive control-based passive fault-tolerant controller is designed to improve vehicle safety, performance and maneuverability when an actuator fault happens. The proposed fault tolerant control method consists of the following three parts: 1) a fault detection and diagnosis (FDD) module that monitors vehicle driving condition, detects and diagnoses actuator failures with the inequality constraints ; 2) a motion controller that computes the generalized forces/moments to track the desired vehicle motion using Model Predictive Control (MPC); 3) a reconfigurable control allocator that redistributes the generalized forces/moments to four wheels with equality constrained optimization. The FTC approach is based on the reconfigurable control allocation which reallocates the generalized forces/moments among healthy actuators once the actuator failures is detected.
Technical Paper
2014-10-13
Bandaru Balaji, L Navaneetha Rao
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
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
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
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
2014-09-30
Saeed Jahangirian, Ashutosh srivastava, Seyed Hosseini, John Kiedaisch, Steven Ballard
Prediction of engine life cycle often requires accurate modeling of thermal stresses in critical regions such as firedeck area under transient loading conditions. A new methodology has been developed in which temperature distributions on cylinder head and crankcase are found using a Conjugate Heat Transfer (CHT) model in Ansys Fluent. Gas side boundary conditions are calculated from cycle-averaged heat transfer in a transient in-cylinder simulation. To reduce the simulation turn-around time and dependency to combustion modeling approach, heat release from a 1-D simulation is distributed in combustion chamber as an energy source term. Volume temperatures and surface heat transfer data are subsequently transferred to ANSYS Thermal finite element solver. Steady state solutions are obtained and validated against experimental data. With the goal of emulating an engine test strategy for fatigue under heat up or cool down cycles, a transient engine loading cycle is simulated. Simulated time-varying temperature traces demonstrate good agreement with transient test data.
Technical Paper
2014-09-30
Harry Dwyer, Seungju Yoon PhD, David Quiros, Mark Burnitzki, Roelof Riemersma, Donald Chernich, John Collins, Jorn Herner
A novel ambient dilution wind tunnel has been designed, tested and used to measure the emissions from “Active Parked Regenerations” of Diesel Particulate Filters (DPFs) for 2007 and 2010 certified heavy duty diesel trucks (HDDTs). The HDDT exhaust was routed to the wind tunnel entrance, and a mixing plate was employed to induce rapid mixing with the ambient air inflow. The tunnel geometry consisted of a 4’ by 4’ cross-section, and the tunnel length was 30’. An induction fan created a flow of 9000 ft3/min (CFM), and velocity and temperature traverses indicated that the mixture of exhaust gases and ambient air was homogeneous at the emission sampling location. The sampling probe was located near the exit of the tunnel, and withdrew 6 CFM from the tunnel centerline for PM measurements. A wide variety of emissions measurements and instrumentation was used in the investigation, which included the following: (1) Engine out On-board diagnostics; (2) Exhaust flow PEMS; (3) Tunnel temperature, CO2, mixture dilution ratio, and relative humidity; (4) Real-time PM instrumentation: EEPS, SMPS, DustTrak, and Dekati Mass Monitor; and (5) Gravimetric filter media.
Technical Paper
2014-09-30
Daofei Li, Huanxiang Xu, Lei Wang, Zhipeng Fan, Wenbo Dou, Xiaoli Yu
Internal combustion engine is expected to be the major power unit to propel vehicles for decades from now on. Therefore, the advanced technologies to improve energy efficiency and to reduce emissions of engine should be continually encouraged and emphasized. For normal driving conditions, nearly half energy of the consumed fuel of engine is wasted, in the form of exhaust heat and coolant heat. In order to recovery the waste heat generated in normal thermodynamic cycle of internal combustion engine, a novel hybrid pneumatic engine concept is proposed, which uses compressed air and fuel as dual energy. During the expansion stroke, additional compressed air is injected, with carefully optimized timing, into the cylinder to absorb the heat released by the fuel, and then the compressed air can do further expansion work. The ideal thermodynamic model of the hybrid pneumatic engine cycle is established and explored, and is used to analyze the influences of the main design parameters on the cycle performance.
Technical Paper
2014-09-30
Hanlong Yang
Adaptive estimation approach for air-path controls in Turbocharged Diesel Engines Due to more stringent emission regulations as well as the customer requirements on performance improvement, the model-based controls in diesel engines are becoming more and more common and necessary. In fact, as diesel engine systems become more complicated with additional hardware, such as throttle, EGR, VVT, VGT, the dynamics of the systems with more freedom of multiple actuators become much more sophisticated. The advanced model-based and coordinated controls become almost the only effective way to improve the system performance. In most of the model based approaches, feedback controls and estimation methods based on real-time dynamics are the key techniques. However since the system has sensors and actuators which have parts-to-parts variations as well as degradation over useful life, therefore any identification of those slow changes and compensation of the controls over the system life cycle is critical for long term control performance, system reliability and diagnostic monitoring.
Technical Paper
2014-09-30
Fabien Redon, John Koszewnik, Gerhard Regner
In August 2011, the U.S. announced the first-ever oil savings standards for heavy-duty trucks and buses. These regulations, targeted at 2014-2018 models, are expected to reduce CO2 emissions by 270 million metric tons and oil consumption by 530 million barrels. Just two weeks ago, President Obama revealed the timeline for Phase 2 of those regulations, which will take effect by March 2016 and extend well into the next decade. With mounting pressure to increase efficiency without increasing cost, truck manufacturers are evaluating technologies—including new engine architectures—to achieve future emissions and fuel economy mandates. The opposed-piston, two-stroke diesel engine was once widely used for on-road applications like the 1950s British Commer truck. But, due to its historic challenges with emissions and oil control, production eventually ceased. However, using computer-aided engineering tools as well as state-of-the-art technologies and engineering practices, Achates Power has developed a modern opposed-piston engine that is clean and delivers better fuel efficiency at lower manufacturing costs when compared to today’s four-stroke engines.
Technical Paper
2014-09-30
Jennifer Wheeler, Gary Hunter, Joshua Stein
Recent advances in natural gas recovery technologies and availability have sparked a renewed interest in using natural gas as a fuel for commercial vehicles. Natural gas can potentially provide for both reduced operating cost and reductions in CO2 emissions. Commercial natural gas vehicles, depending on application and region, will have different performance and fuel consumption targets and are subject to various emissions regulations. Therefore, different applications may require different combustion strategies to achieve specific targets and regulations. This paper summarizes an evaluation of combustion strategies and parameters available to meet these requirements while using natural gas. One combustion strategy that was evaluated was stoichiometric combustion with exhaust gas recirculation (EGR), while the other strategy tested was based on lean-burn combustion. Testing consisted of parametric variations to quantify the effects of swirl ratio, compression ratio, and dilution ratio, either via EGR or excess air, on the operating limits, engine out emissions, and fuel efficiency of spark-ignited natural engines operating in conditions typical for heavy-duty vehicle applications.
Technical Paper
2014-09-30
Quon Kwan, Leverson Boodlal
In this particular field operations test study, the authors demonstrated that telematics can be used to monitor and improve safe and fuel-efficient driving behavior in trucks. Telematics was used to monitor various driver performance parameters: unsafe events (sudden accelerations and hard braking expressed as Yellow and Red events, depending on severity), vehicle speed, engine speed in revolutions per minute (RPM), and fuel economy (miles per gallon). The drivers consisted of two groups: drivers of day cabs and drivers of sleeper cabs. The drivers of both groups were monitored during a baseline period during which no feedback, coaching, or rewards were provided. Then, the drivers of both groups were monitored during an intervention period, consisting of five stages, during which drivers were provided with feedback, coaching, and rewards. As the result of monitoring unsafe events and of driver intervention, drivers of sleeper cabs showed a 55% reduction from the baseline in less severe (Yellow) unsafe events and a 60% reduction from the baseline in more severe (Red) unsafe events.
Technical Paper
2014-09-30
Suman Harapanahalli
Today’s automobiles have wide range of fuel options with the same trend continuing the vehicle will be able to handle more than 2 fuels. It will become cumbersome for the driver to remember different types of fuels that are supported by vehicle. In this paper we introduce an mechanism with which the fuel door opens only if the fuel station can refuel the required fuel for the vehicle. This is achieved using the near field communication. A simple RFID tag is fitted in the fuel nozzle in the station when the nozzle is taped to the fuel door the electronics shall read the type of fuel and only if that fuel is accepted by the vehicle the fuel door is opened.
Technical Paper
2014-09-30
Henry A. Catherino, Fred Feres
Deep charge and discharge cycling of 24 Volt battery strings composed of two 12 Volt VRLA batteries wired in series affects reliability and life expectancy. This is a matter of interest in vehicle power source applications. These cycles include those specific operational cases requiring the delivery of the full storage capacity during discharge. The concern here is related to applications where batteries serve as a primary power source and the energy content is an issue. It is a common practice for deep cycling a 24 volt battery string to simply add the specified limit voltages during charge and discharge for the individual 12 Volt batteries. In reality, the 12 Volt batteries have an inherent capacity variability and are not identical in their performance characteristics. The actual voltages of the individual 12 Volt batteries are not identical. The experimental measurements reveal that one of the two individual batteries in the series configuration is driven to voltages exceeding the acceptable operational limits for a single 12 Volt battery.
Technical Paper
2014-09-30
Christopher Atkinson
Pending GHG emissions reduction legislation for medium and heavy duty vehicles will require the development of engines and powertrains with significantly increased mechanical and electronic complexity. Increasing powertrain efficiency will require the simulation, control and calibration of an expanding number of highly interdependent air, fuel, exhaust, combustion and energy transfer subsystems. As a result, engine and powertrain control is becoming significantly more sophisticated to develop and difficult to optimize. The high cost of developing engines and powertrain systems that demonstrate greater fuel efficiency and emissions benefits than the engines of today, is undeniable. The increased calibration burden and the complexity of optimization require the development and adoption of entirely new methods for transient engine calibration and optimization to achieve maximum vehicle fuel efficiency and lowest regulated emissions. Model-based rapid transient calibration offers significant advantages over traditional testing-intensive methods of calibration.
Technical Paper
2014-09-30
Marius-Dorin Surcel, Yves Provencher
The objective of this project proposed was to compare the fuel consumption and traction performances of 6 × 2 and 6 × 4 tractors. Two approaches have been considered: evaluation of 6 × 2 tractors, modified from 6 × 4 tractors, and evaluation of OEM 6 × 2 tractors. Compared to the 6 × 4 tractors, which are equipped with a rear tandem with both drive axles, the 6 × 2 tractors have a rear tandem axle with one drive axle, and one non-drive axle, also called dead axle. The 6 x 2 tractor configurations are available from the majority of tractor manufacturers. The SAE Fuel Consumption Test Procedures Type II (J1321) and Type III (J1526) were used for fuel consumption track test evaluations. Traction performances were assessed using pull sled tests to compare pulling distance, maximum speed, and acceleration when pulling the same set sled on similar surface. Fuel consumption tests showed that 6 × 2 tractors consume up to 3.5% less than the similar 6 × 4 tractors, whilst pull sled tests showed shorter distance, lower maximum speed, and lower acceleration for the 6 × 2 tractors, when compared to similar 6 × 4 tractors.
Technical Paper
2014-09-30
Philipp Scherer, Marcus Geimer
It was investigated how the energy efficiency of heavy equipment can be determined and evaluated. The wide range of applicability of heavy equipment, as well as the existence of one or more power take-offs require, a special approach for evaluating the energy efficiency of these machines. Therefore, different types of heavy equipment vehicles were equipped with sensors and measurement instrumentation throughout the whole powertrain. With these vehicles, field tests were realised in order to receive perception about the life cycles and the exact kinematic paths of these vehicles as well as to observe the power- and energy flows throughout the powertrain. Parameters were varied in order to receive information about the impact of environmental effects on the energetic- and temporal shares of the kinematic paths. For the analyzation of these measurements a software package has been developed. This package provides features to analyze the kinematic paths of the performed field tests. Furthermore it is possible to show the energy flows within the powertrain for selected time periods.
Technical Paper
2014-09-30
Yang Li, JianWei Zhang
It is also very important to save energy and improve the energy efficiency of the electric vehicle. For the 4WD electric vehicle with PMSM hub motors, the motor drive system is the main energy transmission link. If the efficiency of the motor drive system can be improved, the energy efficiency of the vehicle can also be enhanced, the better performance of motors can be gained and the thermal condition of each hub motor can be improved. As a result, it is very significant to study the torque distribution algorithm between front and rear hub motors in 4WD electric vehicle systems with independently driven wheels to improve the energy efficiency of the vehicle. This paper presents an optimized torque distribution algorithm based on the loss model of multi-motors drive system for the 4WD electric vehicle with PMSM hub motors, which operate at straight line condition. The main content include: develop a comparative accurate mathematical model of permanent magnet synchronous in-wheel motor considering the iron loss and gain the loss model of single motor, which include copper loss, iron loss and mechanical loss ; when the electric vehicle operates at straight line condition, realize the loss model of front and rear motors, which operate at the same speed and torque condition; realize the on-line identification of motor parameters based on the MARS, which is important for updating the efficiency model of the motor drive system when the motor parameters are changing; realize the optimized torque distribution algorithm based on the loss model of the multi-motors drive system to improve the energy efficiency.
Technical Paper
2014-09-30
Yang Li, JianWei Zhang
The driving and braking torque distribution method between front and rear axles for the four-wheel-drive electric vehicles is comparative flexible, and the reasonable distribution method is very significant for improving the vehicle dynamics stability and the energy efficiency. This paper presents from the perspective of improving the vehicle dynamics stability, without regard to the energy efficiency and optimization for the present. In the paper the target of the ideal driving and braking torque distribution, which is gained according to the friction circle of tyre force, is to make the front and rear axles reach at the adhesion limit at the same time when the vehicles operate at various conditions. At first, gain the ideal driving and braking torque distribution when the electric vehicles operate at straight motion condition and the lateral acceleration is zero. Secondly, the ideal driving and braking torque distribution is expanded into the various conditions with the lateral stability demand, which can enhance the limit of lateral stability of the vehicle performance.
Technical Paper
2014-09-30
Jeffrey K. Ball, Mark Kittel, Trevor Buss, Greg Weiss
Trucking fleets are increasingly installing DriveCam video event recorders in their vehicles. The DriveCam system is usually mounted near the vehicle’s rear view mirror, and consists of two cameras – one looking forward and one looking towards the driver. The DriveCam system also contains accelerometers that record lateral and longitudinal g-loading, and some may record vehicle speed (in mph) based on GPS positions. The DriveCam unit constantly monitors vehicle acceleration and speed, and also records video. However, the recorded data is only stored when a preset acceleration threshold is met. The stored data is then uploaded to the DriveCam event center, where it can be analyzed to review driver performance as well as the events before and after the triggering event. The primary use of the system is to assist fleets with driver training and education. However, the recorded data is also being used as a tool to reconstruct accidents. By integrating the accelerometer data, the vehicle speed and distance traveled during the event can be calculated.
Technical Paper
2014-09-30
Ilya A. Kulikov, Elena E. Baulina, Andrey I. Filonov
The paper gives a short description of the University’s developments in the field of hybrid electric powertrains and vehicles, and a survey of theoretical instruments utilized in these developments regarding powertrains control strategies. For the moment, two units fitted with hybrid powertrains are in operation. These are the four-wheel-drive SUV and the powertrain test rig. Both allow to test different powertrain configurations. Prior to implementing a certain configuration in the rig, an extensive theoretical research of powertrain is conducted to reveal its properties and find a way to control it optimally. The basic tool adopted for that purpose is R. Bellman’s dynamic programming (DP). The paper gives an example of applying DP to explore a potential of decreasing fuel consumption and pollutant emissions of van-type vehicle by converting its powertrain into hybrid one. During this study, a contradiction has emerged between minimizing fuel consumption and emissions of NOx. An example shows the way to resolve this contradiction by tuning the cost function.
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
2014-09-30
Matt Zwick
The base design of Commercial Vehicle wheel end systems has changed very little over the past fifty years. Current bearings for R-Drive and trailer wheel end systems were designed from the 1920’s through the 1960’s and have essentially remained the same. Over this same period of time, considerable gains have been made in bearing design, manufacturing capabilities and materials science. These gains allow for the opportunity to significantly increase bearing load capacity and improve efficiency. Government emissions regulations and the need for fuel efficiency improvements in truck fleets are driving the opportunity for re-designed wheel end systems. The EPA and NHTSA standard requires up to twenty three percent reduction in emissions and fuel consumption by 2017 relative to the 2010 baseline for heavy duty tractor combinations. This paper summarizes the history of current wheel end bearing designs and the opportunity for change to lighter weight, cooler running and more fuel efficient wheel bearing designs to help meet the new industry standards.
Technical Paper
2014-09-28
Dongmei wu
With the promotion of electric vehicles, their stability control problem has become increasingly important. Four-wheel-drive electric vehicle can not only control the vehicle stability through hydraulic braking pressure regulation, but also through controlling the motor driving and braking force to generate yaw moment , which are different with the conventional vehicles. In addition, the hydraulic braking system of four-wheel-drive electric vehicle is Electro-Hydraulic Braking System (EHB), rather than the conventional hydraulic braking system. With EHB, the braking pressure in four wheel cylinders can be controlled independently and flexibly, rather than depending on the braking pedal. Besides, there are also several pressure sensors in EHB, which can supply the wheel cylinder pressure information, without the need for pressure estimation. As a result, the way to achieve stability control of four-wheel drive electric vehicle will be different with conventional vehicle. Currently, there are not many researches on the stability control of four-wheel-drive electric vehicle with EHB, and most of them are still at the stage of virtual simulation, lacking testing and applications in real system.
Technical Paper
2014-09-28
Alberto Boretti
Real driving cycles are characterized by a sequence of accelerations, cruises, decelerations and engine idling. Recovering the braking energy is the most effective way to reduce the propulsive energy supply by the thermal engine. The fuel energy saving may be much larger than the propulsive energy saving because the thermal engine energy supply may be cut where the engine operates less efficiently and because the thermal engine can be made smaller. The present paper discusses the state of the art of hydro-pneumatic driveline now becoming popular also for passenger cars and light duty vehicle applications.
Viewing 1 to 30 of 12576