Search Results

Cargo trucks are one of the most important and flexible ways of moving cargo within inlands. In some countries, such as Brazil, the economy relies on them to transport all kinds of products, from field and factory to consumer. In order to reduce freight prices, beside route optimization, truck manufactures started to focus on the aerodynamics development of those vehicles, in order to improve the efficiency, reducing fuel consumption and emissions. Although the truck aerodynamics development is important, most vehicles are not manufactured or don’t consider the truck trailer, which plays a key role in the full aerodynamics performance of the truck, once it might increase the front area and also change the overall aero performance.

The work here presented aims to study different types of ground configurations, located at the test section of a wind tunnel and to check their influence on the drag coefficient of one car, using only computer simulations. The drag coefficient of a vehicle is one of the most important aerodynamic proprieties, and as low as this drag value can be, the car performance will increase and the fuel consumption will decrease, item which has been pursued in new vehicles. Starting from one real wind tunnel test of a small pickup, with static test section ground, a virtual model was built and tested using CFD, following the same configuration of the real test. The difference between test and simulation results was 0.25%, showing that the methodology here used is reliable. After that, two other types of ground were simulated: elevated plate and moving belt and the results show that drag value decreased 0.002 and 0.012 respectively, compared to the value obtained with static ground simulation.

Automakers are seeking more efficient and green vehicles projects in terms of fuel consumption and CO2 emissions. Several factors are directly related to the performance and one of the most important is the aerodynamics. Cars with smooth geometries and transitions are expected to have a better aerodynamic behavior compared with the ones with rough geometries. Regardless the vehicle geometry changes, another way to improve the aerodynamics is by adding new parts, in order to improve the drag coefficient of the car. Most of the time, these parts are added but the functionality is not well defined. The main objective of this work is to identify, explain the way it should work and some applications of additional aeroparts. Those parts could be assembled in a vehicle in order to improve the drag coefficient, have a better fuel economy and lower emissions rate.

The theory related to the thermal comfort of a human being is described in this article. It is not technically and economically feasible to provide optimal thermal comfort to a human being. The air temperature inside the vehicles is inhomogeneous mainly due to the ventilation system and to solar heat flux. The thermal stratification of air that results in difference of heat flux at the human body may cause thermal discomfort. In this case, it is important to quantify the degree of discomfort, which can be represented by the Predicted Mean Vote and Predicted Percentage Dissatisfied indices. This study intends to determine the thermal comfort for a human being inside vehicular cabins considering just the ventilation system with the same ambient temperature. A cabin of a vehicle is virtually reproduced in FLUENT® and the methodology of thermal comfort, based on previous works from the literature, is developed in Matlab 2010a and applied in this simulation.

This study refers to the Computational Fluid Dynamics, demonstrating a comparative between the drag coefficient and the frontal area of a current production car with the same values obtained from a conceptual proposal of removing the outside rearview mirrors of this same vehicle. Both cases were simulated in a virtual wind tunnel with moving ground and rotating wheels condition at speed of 100 kph, aiming to represent the best way a car moving on a highway. The main objective of this paper is improving the efficiency of automotive vehicles by replacing the current outside rearview mirror for cameras placed in smaller structures. The first simulation showed that by removing the outside rearview mirrors both the frontal area of the car and the drag coefficient, which has direct influence on fuel economy calculation, are smaller compared to current solution.

Nowadays, one of the most important roles in vehicle development is the aerodynamic, which aims efficiency on fuel consumption and leads to a green technology. Several initiatives around the world are regulating emissions and efficiency of vehicles such as EURO for European Marketing and the INOVAR Project to be implemented in Brazil on 2017. Thus, this study intend to perform an optimization to minimize the drag force of a hatchback vehicle. The main goal of this work is demonstrate the potential of optimization techniques to provide an aerodynamic shape improvement for the driver side outside rear view mirror of a hatchback vehicle. The optimization solver used in this work is the Adjoint Solver, which makes shape sensitivity analysis and mesh/volume morphing. The study was conducted using CFD simulations to reduce the drag force of current production hatchback vehicle previously validated and correlated in wind tunnel test.

Autonomous vehicles, which are defined as capable of sensing environment and navigating without any human input, are the top trend of the automobilist industry in terms of technology. The computers responsible for the control are able to set the vehicle to optimum operation point. With the advent of Computational Fluid Dynamics -CFD software, it is possible to study drag reduction proposals when the vehicles drive at the velocity, which contributes to increase fuel economy. In this context, based on a sedan virtual drag model, several simulations cases were developed considering different vehicle arrays and changing the distance between each one. The study aims to demonstrate, using virtual simulations, the potential drag coefficient reduction when vehicles are moving in a constant speed and which configuration leads to better performance increment. Taking the isolated vehicle as the baseline value, all the vehicles in the different arrays were analyzed.

Aerodynamics plays a key role in nowadays vehicle development, aiming efficiency on fuel consumption, which leads to a green technology. Several initiatives around the world are regulating emissions and efficiency of vehicles such as EURO for European Marketing and the INOVAR Auto Project to be implemented in Brazil on 2017. In order to meet requirements in terms of performance, especially on aerodynamics, automakers are focusing on aero-efficient exterior designs and also adding deflectors, covers, active spoilers and several other features to meet the drag coefficient. Usually, the aerodynamics properties of a vehicle are measured in both CFD simulations and wind tunnels, which provide controlled conditions for the test that could be easily reproduced. During the real operations conditions, external factors can affect the flow over the vehicle such as cross wind in open highways.

Aerodynamics plays a critical hole in open wheels race cars. The work here presented shows a comparative study of different undertrays design and their influence over the drag coefficient measured on an open wheel prototype race car, using CFD simulations in a virtual wind tunnel. For all cases, velocity was 60 km/h and it was considered both moving ground and rotating wheels to look for a more realist representation of the real interaction between car and racetrack. One model without any aero-part was taken as baseline and three different undertrays proposals were evaluated looking for an aerodynamic improvement. As final results, the drag coefficient of the proposals were ranked and compared with baseline results. Also pressure, velocity and wake images help to illustrate the improvements on the drag coefficient by using an undertray in this vehicle.