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Technical Paper

Boundary Element Energy Method for the Acoustic Prediction of External and Interior Vehicle Noise - Application on a Truck

In the context of more and more drastic noise regulation and increasing customers demand for lower noise annoyance, acoustic shields become essential for a wide range of vehicles. Due to reduced development time, acoustic design must start in the early stage of industrial projects, requiring precise and reactive prediction tools. The most widely used computation methods perform a numerical resolution of Helmholtz equation with a spatial discretization into Finite Elements or Boundary Elements. These methods are efficient in the low frequency range, but they reach their limits at higher frequencies, due to high computational cost, very precise mesh required, and high sensitivity to geometry and frequency. Then Ray Tracing techniques may be an alternative in some cases, but diffused reflection is generally ignored and convergence is not always reached, observation points receiving too few rays.
Technical Paper

Structured Feature Analysis in Heavy Truck Platform Projects

During heavy truck platform development projects there is a need to efficiently evaluate what impact a design change will have on features such as durability, handling and ride comfort in order to optimize and differentiate between design options. Here a structured feature analysis process is presented. The process becomes efficient by modeling all vehicles with a standardized finite element model with predefined sensors. This complete vehicle model allows a large number of vehicle variants to be analyzed with a high quality level.
Technical Paper

Classification of Truck Environments for Fatigue Assessments

A way of modeling vehicle loads for fatigue assessment purposes is discussed. The idea behind the method is that most of the variability in terms of loads is explained by which road the vehicle is driven on. Loads due to curve driving are used as an example. The loads are modeled using a parametric model. Analysis of Variance techniques are used to study the variation and to see whether the classification is sufficiently accurate. Field measurement data from three markets is used. A discussion around design of experiments is given.
Technical Paper

Influence of Different Truck and Trailer Combinations on the Aerodynamic Drag

The aim with this investigation was to study the aerodynamic properties of truck-trailer combinations of varying lengths. The aerodynamic properties of the combinations were evaluated in order to study similarities and differences in the flow field between different configurations. By the use of Computational Fluid Dynamics (CFD) six different types of truck-trailer combinations used for long hauling have been evaluated. The combinations have a total length varying between 10.10 m and 25.25 m and consist of either a tractor or rigid truck in combination with one or two cargo units. All of the combinations are commonly found on roads in Sweden and several other countries in Europe. The results from the simulations show that the aerodynamic properties differ significantly for the truck-trailer combinations. It was found that the longer vehicle combinations are much more sensitive to yaw conditions than the shorter combinations.
Technical Paper

Development of Transient Simulation Methodologies for Underhood Hot Spot Analysis of a Truck

This paper presents the efforts done by Volvo 3P, through a partnership with ThermoAnalytics Inc, to develop transient thermal simulation methodologies of the under hood of a truck. The verification process for the hot spots analysis currently in use at Volvo 3P is described and the key transient situations for the hot spots analysis are identified: hot shutdown, DPF regeneration and long drive cycle, are currently only covered by physical testing late in the project, contrary to steady-state operating conditions that are already managed through simulations in the early stage of the development phase. The goal of this work is to develop simulation methodologies for these transient situations which are likely to increase the efficiency of the verification process. The key issues to be satisfied are to minimize the model development and the simulation times while achieving an acceptable accuracy level.
Technical Paper

The Right Truck for the Job with Global Truck Application Descriptions

Global Truck Application (GTA) defines a number of parameters that specify differences in driving and transport conditions for haulage operations worldwide. The aim is to provide a uniform perspective on truck use, guaranteeing that the company “speaks the same language” within all its divisions and departments – product planning, product development, sales and aftermarket. It provides a framework for developing a modularized vehicle platform with an optimal set of differentiated variants to give full flexibility for specifying the most transport-efficient solution for each individual customer.
Journal Article

Experimental and Numerical Investigation of Wheel Housing Aerodynamics on Heavy Trucks

Wheel and underbody aerodynamics have become important topics in the search to reduce the aerodynamic drag of the heavy trucks. This study aims to investigate, experimentally as well as numerically, the local flow field around the wheels and in the wheel housing on a heavy truck; and how different approaches to modelling the wheel rotation in CFD influences the results. Emphasis is on effects due to ground simulation, and both moving ground and wheel rotation were requirements for this study. A 1:4-scale model of part of a heavy truck geometry has been developed. During the model design numerical simulations were used to optimise the shape, in order to replicate the flow field near the wheel of a complete truck. This was done by changing the flow angles of the incoming and exiting flows, and by keeping the mass flow rates in to, and out of, the wheel housing at the same ratios as in a reference full size vehicle.
Technical Paper

Aerodynamic Effects of Roof Deflector and Cab Side Extenders for Truck-Trailer Combinations

Today there are a large variety of drag-reducing devices for heavy trucks that are commonly used, for example, roof deflectors, cab side extenders and chassis fairings. These devices are often proven to be efficient, reducing the total aerodynamic resistance for the vehicle. However, the drag-reducing devices are usually identical for a specific pulling vehicle, independent of the layout of the vehicle combination. In this study, three vehicle combinations were analyzed. The total length of the vehicles varied between 10.10 m and 25.25 m. The combinations consisted of a rigid truck in combination with one or two cargo units. The size of the gap between the cargo units differed between the vehicle combinations. There were also three configurations of each vehicle combination with different combinations of roof deflector and cab side extenders, yielding a total number of nine configurations.