Browse Topic: Vehicle front ends
In today’s scenario, internal combustion engines have conflicting requirements of high power density and best in class weight. High power density leads to higher loads on engine components and calls for a material addition to meet the durability targets. Lightweight design not only helps to improve fuel economy but also reduces the overall cost of the engine. Material change from cast iron to aluminium has a huge potential for weight reduction as aluminium has 62% lesser mass density. But this light-weighting impacts the stiffness of the parts as elastic modulus drops by around 50%. Hence, this calls for revisiting the design and usage of optimization tools for load-bearing members on the engine to arrive at optimized sections and ribbing profiles. This paper discusses the optimization approach for one of the engine components i.e., the FEAD (front end accessory drive) bracket. FEAD brackets are used to mount one or more auxiliary components and are subjected to vibrational loads due
In the present work, it is investigated how a flush arrangement to the outer skin affects the aerodynamic characteristic curve of active grille shutters (AGS). For this purpose, a recently developed theory, which analytically describes the aerodynamic behavior of AGS arranged in a straight flow channel, is extended accordingly, and the influence of an arrangement of AGS flush with the outer skin is first theoretically analyzed. The theoretical results are then validated experimentally. For this purpose, measurements of real vehicles with suitable AGS are used. The results show a good agreement of the theoretical predictions with the experiment. The theoretical and experimental analyses allow conclusions to be drawn as to how and under what conditions an arrangement flush with the outer skin affects the aerodynamic behavior of AGS
In autonomous driving system, lane change decision-making plays an important role as the front-end of lateral control. However, the current prediction methods of lane change are typically performed by using basic variables as the features of model without deep processing, which reduces the accuracy of the prediction. Therefore, we propose a binary logistic regression method to solve the lane change decision problem under expressway conditions, which treat quantified willingness and risk as the inputs. Firstly, we design Lane Changing Willingness function and Lane Changing Risk function with the minimum safety spacing theory and traffic environment factors. Secondly, a binary logistic regression method for predicting lane change behavior is proposed. Thirdly, we develop the driving simulation platform with low latency data collecting tools and design the experiments. After training the model with the experiment data, the proposed method predicts the lane change decision with 94.02
During the development phase of any Powertrain component/subsystem for a conventional ICE or an XEV (Hybrid/Battery Electric Vehicle), system Energy efficiency and Performance improvement simulations are a very important step to prove the worthiness of the product before we can advance to building Prototypes, Vehicle level Integration, Testing, analysis and benefit’s evaluation phases. This work describes how two simulation tools have been leveraged effectively for Energy efficiency and Performance simulations for an Electric vehicle. Schaeffler has an internal Physical Modelling Tool (PMT) for building vehicle level models. This tool has readymade physical blocks for various Mechanical and Electrical components. These blocks can be parameterized as per required specifications. The powertrain subsystems like the Battery, BLDC Motor, Vehicle Dynamics and the Multi-speed transmission consisting of various mechanical elements have been modelled and parametrized using this tool. This tool
As per WHO 2018 report, pedestrian fatalities account for 23% of world road accident fatalities. Every day 850 pedestrians lose their lives in the world. As per MoRTH 2018 report, 16% of road accident fatalities are of pedestrians in India. Everyday 64 pedestrians lose their lives in India. Based on accident data, one of the most common reason for the pedestrian fatality is head injury due to primary contact from vehicle front-end structure. Pedestrian head injury performance highly depends on front-end styling, bonnet stiffness, clearance with aggregates underneath the bonnet and hard contact points. During concept stage of vehicle development, safety recommendation on front-end design is provided based on geometric assessment of the class A surface. This paper presents the novel approach of using machine-learning algorithms to predict the head injury performance at the early stage of vehicle design using the knowledge of existing vehicle simulation data and new vehicle design
Currently the Automotive industry demands highly competitive product to survive in the global tough competition. The engine cooling system plays a vital role in meeting the stringent emission norms and improving the vehicle fuel economy apart from maintaining the operating temperature of engine. The airflow through vehicle subsystems like the grille, bumper, the heat exchangers, the fan and shroud and engine bay are called as front-end flow. Front end flow is crucial factor in engine cooling system as well as in determining the aerodynamic drag of vehicle. The airflow through the engine compartment is determined by the front-end vehicle geometry, the CRFM and CAC package, the engine back restriction and the engine compartment geometry including the inlet and outlet sections. This paper discusses the 1D modelling method for front-end airflow rate prediction and thermal performance by 1D method. The underbody components are stacked using heat stack and simulated in pressure mode
Two-layer engine front end accessory drive systems (TEFEADS) are adopted generally by commercial vehicles due to the characteristics of the accessory pulleys, which have large torque and moment of inertia. An overrunning alternator decoupler (OAD) is an advanced vibration isolator which can reduce the amplitude of torsional vibration of alternator rotor effectively by an one-way transmission and they are more and more widely used in vehicles. This paper established a model of a generic layout of a TEFEADS with an OAD. The coupling effect between the TEFEADS, the nonlinear characteristics of OAD, the torsional vibration of crankshaft and the creeping on the belt were taken into account. A nine pulleys model was provided as a study example, the dynamic responses, which are respectively under steady and accelerating conditions, of the system were calculated by the established method and compared with the bench experiment. The influence of different belt material, the stiffness of OAD
An automatic tensioner with an asymmetric damping structure used in an engine front end accessory drive system is analyzed. An analytical model is established to calculate the hysteretic behavior of the tensioner. The contact characteristics of contact pairs are modeled and investigated for disclosing relation between contact pair, friction and hysteretic loop of an automatic belt tensioner. The presented models are validated by a torque measurement versus angular displacement of a tensioning arm. The errors between the calculation and the measurement are analyzed. The working torques of the tensioner during loading and unloading process are described by a bilinear hysteretic model and are written as a function with a damping ratio. The influence of damping structure parameters on the hysteretic torque is investigated. The method presented in this paper can be used for predicting the nonlinear characteristics of a tensioner before prototyping
A multi-year Power System R&D project was initiated with the objective of developing an off-road hybrid heavy-duty concept diesel engine with front end accessory drive-integrated energy storage. This off-road hybrid engine system is expected to deliver 15-20% reduction in fuel consumption over current Tier 4 Final-based diesel engines and consists of a downsized heavy-duty diesel engine containing advanced combustion technologies, capable of elevated peak cylinder pressures and thermal efficiencies, exhaust waste heat recovery via SuperTurbo™ turbocompounding, and hybrid energy recovery through both mechanical (high speed flywheel) and electrical systems. The first year of this project focused on the definition of the hybrid elements using extensive dynamic system simulation over transient work cycles, with hybrid supervisory controls development focusing on energy recovery and transient load assist, in Caterpillar’s DYNASTY™ software environment. Three key off-road applications were
Tractor weight transfer is the most common farm-related cause of fatalities nowadays. As in India it is getting mandatory for all safety devices across all HP ranges. Considering any changes in the weight from an attachment such as Rops, PTO device, tow hook and draw bar etc. can shift the center of gravity towards the weight. center of gravity is higher on a tractor because the tractor needs to be higher in order to complete operations over crops and rough terrain. Terrains, attachments, weights, and speeds can change the tractor’s resistance to turning over. This center of gravity placement disperses the weight so that 30 percent of the tractor’s weight is on the front axle and 70 percent is on the rear axle for two-wheel drive propelled tractors and it must remain within the tractor’s stability baseline for the tractor to remain in an upright position. In our present study formulating the prediction of tractor CG by using a modified excel spreadsheet package employing the parameters
One of the key inputs 1-D transient simulation takes is a detailed front end cooling flow map. These maps that are generated using a full vehicle Three-dimensional Computational Fluid Dynamics (3D CFD) model require expensive computational resources and time. This paper describes how an adaptive sampling of the design space allowed the reduction of computational efforts while keeping desired accuracy of the analysis. The idea of the method was to find a pattern of Design of Experiments (DOE) sampling points for 3D CFD simulations that would allow a creation of an approximation model accurate enough to predict output parameter values in the entire design space of interest. Three procedures were implemented to get the optimal sampling pattern. One of them, called Procedure #1 below employed the observations listed below, identification of the areas that would require less sampling points by analyzing approximation errors, manual reduction of the points in such areas, building an
Overall cycle time and prototype testing are significantly decreased by assessment of cooling module performance in the design stage itself. Hence, Front End Cooling and Thermal Management are essential components of the vehicle design process. Performance of the cooling module depends upon a variety of factors like frontal opening, air flow, under-hood sub-systems, module positioning, front grill design, fan operation. Effects of design modifications on the engine cooling performance are quantified by utilizing computational fluid dynamics (CFD) tool FluentTM. Vehicle frontal configuration is captured in the FE model considering cabin, cargo and underbody components. Heat Exchanger module is modelled as a porous medium to simulate the fluid flow. Performance data for the Heat Exchanger module is generated using the 1D KuliTM software. In this paper, CFD simulation of Front End Cooling is performed for maximum torque and maximum power operating conditions. Analysis results predict and
The generator is an important loaded component of an engine front end accessory drive system (EFEADS). With a huge moment of inertia and a highest running speed, the vibration and noise often occurs in operation, which has an effect on the service life. Thus an overrunning alternator decoupler (OAD) is used in the EFEADS for reducing the vibration of system. In this paper, a model of EFEADS with an OAD is established. The impact of the OAD on the dynamic responses of pulley of generator and the system are analyzed, and is verified by bench experiments. And the influence of parameters, such as spring stiffness, moment of inertia of generator and loaded torque on the dynamic performances of the system are studied. The influence of misalignment in pulleys on the dynamic performance of system is also discussed. The presented method is useful for optimizing the dynamic performance of system, such as the oscillation of tensioner arm and the slip ratio of the belt-generator pulley
As pedestrian protection tests and evaluations have been officially incorporated into new C-NCAP, more stringent requirements have been placed on pedestrian protection performance. In this study, in order to reduce the injury of the vehicle front end structure to the pedestrian's lower extremity during the collision, the advanced pedestrian legform impactor (aPLI) model was used in conjunction with the finite element vehicle model for collision simulation based on the new C-NCAP legform test evaluation regulation. This paper selected the key components which have significant influences on the pedestrian's leg protection performance based on the CAE vehicle model, including front bumper, front-cover plate, upper impact pillar, impact beam and lower support plate, to form a simplified model and conducted parametric modeling based on it. Then, the variable correlation analysis was carried out on the sample results obtained from the design of experiment (DOE), and the contribution analysis
This research focuses on the use of Event Data Recorders (EDR) to assist in calculating speed loss or ΔV undergone by a motorcycle in a broadside type impact into a vehicle. If the struck vehicle has EDR data, this could be a useful tool in calculating motorcycle ΔV or corroborating motorcycle ΔV calculations from crush or other methodologies. Certain parameters critical to calculation of motorcycle ΔV must be considered, including the appropriate effective mass to use for the motorcycle/rider combination. This study used crash test data to determine a method of applying parameter values to accurately calculate motorcycle ΔV in a motorcycle-vehicle collision. In this study, three crash tests were performed in which a motorcycle with a dummy rider traveling in the range of 42 to 51 mph collided into the right front corner of a vehicle traveling between 5 and 16 mph. In all three tests, both the vehicle and motorcycle were instrumented with triaxial accelerometers and triaxial rate gyros
The automatic tensioner is an important component of the engine front end accessory drive system (EFEADS). It maintains the tension of the belt steadily and reduces the slip of pulley, which is benefit for improving the life of V-ribbed belt. In this paper, an EFEADS model is established which is considering with the hysteretic behavior and the asymmetry of friction damping of a tensioner. A four-pulley EFEADS is taken as a study subject. The dynamic responses of system, such as the oscillation angle of each pulley, the slip factor of pulley, the oscillation of tensioner arm and the dynamic belt tension are analyzed with symmetric damping and asymmetric damping tensioner. Meanwhile, the influence of asymmetric damping factors of tensioner on the dynamic response of EFEADS is also investigated. The experimental results show that tensioner with an asymmetric damping can effectively reduce the oscillation angle of each pulley and the oscillation of tensioner arm, and the fluctuation of
A model for a generic layout of an engine front end accessory drive system is established. The dynamic performances of the system are obtained via a numerical method. The dynamic performances consist of the oscillation angle of tensioner arm, the slip ratio of each pulley and the dynamic belt tension. In modeling the system, the hysteretic behavior of an automatic tensioner, the loaded torque of the accessory pulley versus the engine speed, the torsional vibration of crankshaft and the creep of the belt are considered. The dynamic performances of the system at steady state and under accelerating condition are analyzed. An example is provided to validate the established model. The measured results show that the torsional vibration of crankshaft is larger and the dynamic performances of the system are different under accelerating conditions, though the acceleration is small. In the end, the dynamic performances of the system using different belts with different Young’s modulus are
Design and production of an assembly system for a major aircraft component is a complex undertaking, which demands a large-scale system view. Electroimpact has completed a turnkey assembly line for producing the wing, flap, and aileron structures for the COMAC C919 aircraft in Xi’an, China. The project scope includes assembly process design, material handling design, equipment design, manufacture, installation, and first article production support. Inputs to the assembly line are individual component parts and small subassemblies. The assembly line output is a structurally completed set of wing box, flaps, and ailerons, for delivery to the Final Assembly Line in Shanghai. There is a trend toward defining an assembly line procurement contract by production capacity, versus a list of components, which implies that an equipment supplier must become an owner of production processes. The most significant challenge faced was the amount of front end engineering work required to develop
This standard covers ultra-thin wall low voltage primary cable intended for use at a nominal system voltage of 60 VDC (60 VAC rms) or less in surface vehicle electrical systems. The tests are intended to qualify cables for normal applications with limited exposure to fluids and physical abuse. This standard covers SAE conductor sizes which usually differ from ISO conductor sizes
This SAE Recommended Practice provides a systematic method for the identification of End Mills. It is intended to assist in the cataloging and supplying of these tools. NOTE 1— Caution must be taken when assigning codes for designation to prevent specifying cutting tools that cannot be physically or economically manufactured. NOTE 2— In particular without limitation, SAE disclaims all responsibility for the accuracy or completeness of information contained within this report if the standards of this report are retrieved, combined, or used in connection with any software
This SAE Recommended Practice applies to three-point hitch (Type A) backhoes as defined in SAE J326 when mounted on either an agricultural tractor as defined in ANSI/ASAE S390 or other off-road self-propelled work machine as defined in SAE J1116. This criterion is intended for the manufacturer of the backhoe, whether or not the backhoe is manufactured or marketed by the same company that manufactures or markets the propelling machine
The aim is to develop a theory to describe the aerodynamic behavior of active grille shutters (AGS). The theory correlates the cooling air mass flow and drag of a vehicle with the angle and number of air flaps on the AGS. The relatively simple mathematical formulation of this theory provides an insight into the aerodynamic behavior and characteristic curve shape of AGS. It illustrates how the number of air flaps changes and influences the shape of the AGS characteristic curve. The theory is validated by experiments using wind tunnel measurements on real vehicles with AGS. The comparisons show good agreement between theory and experiment
An automatic tensioner used in an engine front end accessory drive system (EFEADS) is taken as a study example in this paper. The working torque of the tensioner, which consists of the spring torque caused by a torsional spring and the frictional torques caused by the contact pairs, is analyzed by a mathematic analysis method and a finite element method. And the calculation and simulation are validated by a torque measurement versus angular displacement of a tensioner arm. The working torques of the tensioner under a loading and an unloading process are described by a bilinear hysteretic model, and are written as a function with a damping ratio. The rule of the action for the damping devices is investigated based on the simulation and a durability test of the tensioner. A finite element method for the tensioner without damping device is established. Then the radial deformation for the torsional spring under an unconstrained state is obtained. The analysis results have a good
Rapid adoption of mobile platforms such as smartphones and tablet computers has increased the range of applications and data on mobile devices. The use of these devices to communicate sensitive or confidential data requires, among other things, strong front-end user authentication procedures and/or protocols to protect the sensitive or confidential data, the devices themselves, and the integrity of networks carrying such data. Traditional methods of front-end user authentication such as typed-in password or graph-match patterns on the screen can be stolen or obtained by coercion
In most of the countries all over the world, thousands of pedestrians and vulnerable road users are struck by motor vehicles and getting killed or get severe injuries. Accident research data shows that pedestrians are a significant proportion of all road user casualties [1]. In pedestrian impact with vehicle front end, several organ forms impact directly to front end of the vehicles and get severe injuries in head, lower leg and pelvis region. Pelvis region of pedestrian get severe injuries due to hit by Bonnet Leading Edge. Impact force is major injury driving parameter in case of pelvis region. In earlier Euro NCAP Pedestrian Protocol -v7.1.1 [2], upper leg impact energy calculation was based on BLE (Bonnet Leading Edge) height and bumper lead. Vehicle front end styling was not playing any role in deciding upper leg impact energy. Upper leg impact performance was purely dependent on BLE height and package space available. Whereas in current Euro NCAP Pedestrian Protocol -v8.4 [3
This SAE Recommended Practice establishes methods to determine grade parking performance with respect to: a Ability of the parking brake system to lock the braked wheels. b The trailer holding or sliding on the grade, fully loaded, or unloaded. c Applied manual effort. d Unburnished or burnished brake lining friction conditions. e Down and upgrade directions
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