This paper presents the results of an extensive development and validation process to produce a highly accurate and reproducible external aerodynamics simulation methodology. The approach makes use of a specialized volume meshing methodology with controllable cell quality metrics and an incompressible Delayed Detached Eddy Simulation (DDES) flow solver to consistently predict the aerodynamic forces on a range of different vehicle shapes. In addition a wizard-like graphical user interface (GUI) has been developed that streamlines the set-up process and applies vehicle dependent best practices derived during the validation process.
Several measures have been taken to improve the robustness, accuracy and speed of the flow solver. These include solution adaptive discretization, improved DDES turbulence modelling and various mesh generation developments to enhance the fidelity of the computational grid. Significantly improved solution times have also resulted from a combination of variable time-step sizes and extensive optimization of solver settings for the types of grids employed.
Over 100 vehicle types and permutations have been used for the validation and best-practice development. In each case wind tunnel data is compared with CFD results in an iterative and recursive fashion, as best-practices evolve. Vehicle shapes used in the validation include: sedans, hatchbacks, estates and SUVs, motorsport applications, as well as both light and heavy duty trucks. In addition to different vehicle shapes a wide range of experimental configurations were evaluated including different ground simulation techniques, yaw angles, ride heights and test speeds. Although the focus was on improving absolute accuracy, variations in drag for different swappable parts and configurations were also checked for directionality and magnitude.
Innovative high porosity SCR substrates are targeting at optimum utilization of high catalyst amounts without
increasing pressure drop. Mathematical modeling of such technologies is challenging, requiring accurate description of both chemistry and mass transfer inside the active material. In this work, a systematic experimental study is conducted towards calibrating a comprehensive commercial simulation model for a Cu-zeolite SCR catalyst. Based on the calibrated model, it is possible to evaluate different substrate technologies with respect to NOX conversion, pressure drop and packaging volume reduction potential.
The application of a full vehicle model with MBS (>100 DOF) in real time has now become reality. This makes it possible to efficiently evaluate vehicle handling performance in the whole vehicle. An array of chassis design parameters (e.g. geometries, kinematics, hard points) can be evaluated in combination with systems (e.g. air suspensions, steering, powertrain). New applications are possible, such as the MIL, SIL and HIL tool chain, to validate the interactions with controllers and their variants. Tools and methods (e.g. automation, analysis) can be added. Best combinations can be achieved by using DoE methods - transferred from powertrain ECU calibration.
This study demonstrates crankshaft counterweight profile optimization to achieve better dynamic balancing. Balancing simulation was carried to predict initial unbalance. During balancing of actual crankshaft, the position of unbalance is sometimes shifted due to machining stock distribution towards non-favorable direction resulting into more number of balancing holes, thus productivity loss. To reduce this, counterweight profile optimized. After balancing, bending fatigue test carried out. Crankshaft exhibited pre-mature failure at unusual location. To determine the reason of failure, stress analysis was performed using FEA. Design enhancement solution proposed to reduce the stresses & subsequently enhance bending fatigue strength.
Bicyclists move at speed equivalent to a slowly moving vehicle, and sometimes share the road with vehicles in urban environments. Thus, bicyclists take more challenge for safe-driving compared to pedestrians. Therefore, accident avoidance system is expected to recognize the type of road user, and then can perform further behavior analysis for risk assessment based on the type of road user. Our contribution to this tendency consists of a method to distinguish bicyclists from pedestrians, and reliably estimate the bicyclists’ head orientation and body orientation from image sequences taken by an on-board camera. The output of the proposed method can be used for risk assessment.
This work represents a continuation of the earlier results published by authors on combustion and emission
investigation of Hydrogenated Vegetable Oil on a High Efficiency Diesel Combustion System (SAE Paper:2013-01-1677). In present work the investigations are extended to analyze the impact of HVO fuel on characteristics of Particulate Matter emissions and regeneration behavior of Diesel Particulate Filter (DPF). The experiments were performed with pure HVO fuel, petroleum diesel and Biodiesel (RME/B100). Results suggest that activation energy of HVO soot oxidation decreased by ~ 6 KJ/mol as compared to soot from diesel fuel, leading to a decrease of DPF regeneration temperature by ~ 43 °C.