Adjoint optimization is an exciting and fast growing field that has many applications in the automotive industry. We focus on the usage of adjoint for the optimization of aerodynamic performance. While adjoint methods have come to the attention of mainstream CFD through inclusion in prominent commercial codes, most of the available tools are severely limited, precluding productive use in this field. We detail a methodology that is based on the continuous adjoint method and is implemented in an Open Source framework. While more mathematically demanding in terms of its derivation, the continuous adjoint method requires orders of magnitude fewer resources without sacrificing significant accuracy. In this paper continuous adjoint methods are used for calculating gradients of aerodynamic objective functions (drag, lift, moments etc.) in applications with a huge number of design variables. Methodologies that accept either steady-state RANS(1)(2)(3) or time averaged DES(4)(6) as primal flow input are outlined and extensions to improve the accuracy of previously published methods are detailed. Finally, a novel methodology, based on volumetric B-splines to translate the surface sensitivities produced by the adjoint into optimized shapes, is introduced and showcased.
Small size objects which dimensions are around 0.15m are one of the major security risks to driving vehicles in the highway. Lidar and radar are hard to detect this kind of objects due to the sparsity of their detecting signal. Vision based methods are possible to solve this problem because camera can generate dense information. We propose a new method to detection small objects in the highway based on stereo vision. This method uses Multi-Path-Viterbi algorithm to obtain dense depth information of stereo images. Based on the depth information, road surface can be detected. Objects on road can be mapped to the 3D space to determine their size and location, then small objects dangerous to the host Vehicle can be recognized and located.
To improve the accuracy of Injury Severity Prediction in the event of vehicle crash, a new methodology is proposed using the US vehicle accident database (NASS-CDS). This proposed method is an extension of the base algorithm introduced by Kononen et al. in which, some of the additional variables were introduced and branched logistic regression methodology was used. Results suggest that the proposed branching method has some advantage over the base algorithm due to better linearization of the complex multidimensional non-linear relationship of the input and output variables.
HFO-1234yf is a low GWP refrigerant developed for automotive air-conditioning (A/C) systems to replace HFC-134a. Industry-wide risk assessments found that HFO-1234yf can be safely used in mobile A/C applications with results previously presented. Various global automotive OEMs have transitioned to HFO-1234yf at selected manufacturing sites in different regions. This paper documents critical steps for successful transition, including installation, commissioning and startup of storage and vehicle charging facilities. Observations will also be shared concerning potential pit-falls that have been encountered during new refrigerant implementation at these sites
The purpose of this study is to provide the alignment of whole spine in an automotive seated posture by analyzing image data acquired with an upright open MRI system. Five female and three male asymptomatic subjects were scanned in seated and supine postures, and midsagittal images were analyzed in the location of the center of vertebral body and the vertebral angle relative to lower adjacent vertebra from C2 to sacrum. Results showed that 1) females were more likely to have non-lordosis than males, 2) lumbar lordosis was larger for females than males, and sacrum slope was greater for males than females, 3) thoracic kyphosis and T1 slope were greater for the cervical lordotic type than kyphotic type in seated posture.
Despite decades of research and regulation, brain injuries remain a leading cause of traffic related death and disability worldwide. In this study, the human tolerance to brain injury was investigated by applying pure angular and linear kinematic loading conditions in the sagittal plane to a finite element model of the head. The relationship between peak acceleration and impact duration was determined at several levels of constant injury risk for two strain-based injury criteria. Results revealed that brain injury tolerance depends on peak acceleration and impact duration, which were found to be inversely related for constant injury risk.
In order to identify the height alignment with a standard-sized pedestrian that best estimates the whole body trajectories by scaling those of a pedestrian in a different size, car-to-pedestrian collision simulations were conducted using five production car models in the small sedan category, human FE models in three sizes and five aligned points with the standard-sized pedestrian. The trajectories from the simulations were scaled using the distance between the aligned point and the measurement point of the trajectory. The results showed that aligning with the knee-joint height provided the best estimation of the trajectories in the small sedan category.