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Fuel consumption of vehicles has received increased attention in recent years; however one neglected area that can have a large effect on this is the energy usage for the interior climate. This study aims to investigate the energy usage for the interior climate for different conditions by measurements on a complete vehicle. Twelve different NEDC tests in different temperatures and thermal states of the vehicle were completed in a climatic wind tunnel. Furthermore one temperature sweep from 43° to −18°C was also performed. The measurements focused on the heat flow of the air, from its sources, to its sink, i.e. compartment. In addition the electrical and mechanical loads of the climate system were included. The different sources of heating and cooling were, for the tested powertrain, waste heat from the engine, a fuel operated heater, heat pickup of the air, evaporator cooling and cooling from recirculation.

Squeak and rattle (S&R) are nonstationary annoying and unwanted noises in the car cabin that result in considerable warranty costs for car manufacturers. Introduction of cars with remarkably lower background noises and the recent emphasis on electrification and autonomous driving further stress the need for producing squeak- and rattle-free cars. Automotive manufacturers use several road disturbances for physical evaluation and verification of S&R. The excitation signals collected from these road profiles are also employed in subsystem shaker rigs and virtual simulations that are gradually replacing physical complete vehicle test and verification. Considering the need for a shorter lead time and the introduction of optimisation loops, it is necessary to have efficient and inclusive excitation load cases for robust S&R evaluation.

In recent years fuel consumption of passenger vehicles has received increasing attention by customers, the automotive industry, regulatory agencies and academia. However, some areas which affect the fuel consumption have received relatively small interest. One of these areas is the total energy used for vehicle interior climate which can have a large effect on real-world fuel consumption. Although there are several methods described in the literature for analyzing fuel consumption for parts of the climate control system, especially the Air-Condition (AC) system, the total fuel consumption including the vehicle interior climate has often been ignored, both in complete vehicle testing and simulation. The purpose of this research was to develop a model that predicts the total energy use for the vehicle interior climate. To predict the total energy use the model included sub models of the passenger compartment, the air-handling unit, the AC, the engine cooling system and the engine.

During 1991 Volvo Car Corporation has introduced the new Volvo 850 GLT model featuring front wheel drive with transverse installation of the engine and gearbox. The powertrain; consists of a new in-line five-cylinder engine in combination with a four speed electronically controlled automatic gearbox or a five speed manual gearbox. The engine features DOHC 20 valves, V-VIS (Volvo Variable Induction System), well tuned exhaust system and microprocessor controlled engine management systems. The engine was designed and developed as a new member of Volvo's modular engine family. The first member was the in-line six-cylinder engine B6304F [1] introduced in 1990. The modular engines have a large number of identical components and the major components are machined in common transfer lines which makes the manufacturing process highly rational and cost-effective.

The low frequency acoustic response of the passenger compartment (cavity) in sedans is considered with respect to the coupling between the cavity and the trunk. Both acoustic (via holes in the parcel shelf or behind the backrest of the rear seat), and structural (via the parcel shelf itself, or the panel of the backrest) mechanisms are investigated by both test and CAE. It is found that the peaks in acoustic response of the cavity at low frequencies are due to both acoustic and structural phenomena. However, the acoustic ones can be effectively blocked by proper design of the trim. Recommendations concerning modeling of acoustic effects in sedans are formulated.

The principles of an electronic nose are described briefly. It is shown how a sensor array in combination with pattern recognition software can be used for quality control and classification of car interior trim materials. Anomalies such as bad smelling leather and carpet are shown as outliers. The results are consistent with GC-MS TVOC measurements as well as with data from a human sensory panel. More needs to be done, however, regarding the sensor stability in particular before the sensor array can be used for routine classification of the trim materials.

To give the customer an immediate impression of quality several of criteria must be fulfilled such as styling, paint finish and fitting of outer panels/closures. Therefore, higher demands on geometrical quality e.g. stability for both exterior and interior are needed. The structural part of the car body is the key element for success. Beside the visual impression, lack of noise and vibrations during driving can convince a potential buyer to become an actual customer. To achieve this, car manufacturers have to draw up an overall strategy in combination with proper working methods to be able to guarantee a stable geometrical output throughout the entire development process and during series production over the lifetime of the vehicle. On a simultaneous engineering basis, the OEM, the system/component- and the process suppliers (for the industrial system from press shop to final assembly) have to adopt a common measurement strategy.

During the development of the aerodynamic properties of fore coming road vehicles down scaled models are often used in the initial phase. However, if scale models are to be utilised even further in the aerodynamic development they have to include geometrical representatives of most of the components found in the real vehicle. As the cooling package is one of the biggest single generators of aerodynamic drag the heat exchangers are essential to include in a wind tunnel model. However, due mainly to limitations in manufacturing techniques it is complicated to make a down scaled heat exchanger and instead functional dummy heat exchangers have to be developed for scaled wind tunnel models. In this work a Computational Fluid Dynamics (CFD) code has been used to show that it is important that the simplified heat exchanger model has to be of comparable size to that of the full scale unit.

Traditional approaches to pollution control have been to develop benign non-polluting processes or to abate emissions at the tailpipe or stack before emitting to the atmosphere. A new technology called PremAir®* Catalyst Systems takes a different approach and directly reduces ambient ground level ozone. This technology can be applied to both mobile and stationary applications. For automotive applications, the new system involves placing a catalytic coating on the car's radiator or air conditioner condenser. As air passes over the radiator or condenser, the catalyst converts the ozone into oxygen. Three Volvo vehicles with a catalyst coating on the radiator were tested on the road during the 1997 summer ozone season in southern California to assess performance. Studies were also conducted in Volvo's laboratory to determine the effect of the catalyst coating on the radiator's performance with regard to corrosion, heat transfer and pressure drop.

This paper describes the development of a robust and accurate method to model one-phase heat exchangers in complete vehicle air flow simulations along with a comprehensive comparison of EFD and CFD results. The comparison shows that the inlet radiator coolant temperatures obtained with CFD were within ±4°C of the experimental data with a trend in the differences being dependent on the car speed. The relative differences in cooling air mass flow rates increase with increasing car speed, with CFD values generally higher than EFD. From the investigation, the conclusion is that the methodology and modeling technique presented offer an accurate tool for concept and system solutions on the front end design, cooling package and fan. Care must be taken in order to provide the best possible boundary conditions paying particular attention to the heat losses in the engine, performance data for the radiator and fan characteristics.

Car body structures and the joints between beam members have a great impact on global vehicle stiffness. With the method presented in this paper it is possible to experimentally assess the stiffness of joints by a robust and economic means. The stiffness of a beam can easily be found experimentally just by cutting it in two and using the cross-sections to calculate the polar moment of inertia. When it comes to a joint, there are no formulae or explicit expressions describing its behavior. Therefore, measurement of its mechanical behavior has to be made. The dynamic joint method presented here does not need levers or a costly, rigid set-up, but an economical free-free set-up and cast-on weights. Furthermore, the same method can be emulated by FEM when a digital model exists.

In the early days of the automotive industry, durability and reliability were hit or miss affairs, with end-users often being the first to know about any durability problems - and in many cases forming an essential part of the development process. More recently, automotive companies have developed proving ground and laboratory test procedures that aim to simulate typical or severe customer usage. These test procedures have been used to develop the products through a series of prototypes and to prove the durability of the product prior to release in the marketplace. Now, commercial pressures and legal requirements have led to increasing reliance on CAE methods, with fatigue life prediction having a central role in the durability engineering process.

In the continuous struggle to improve car body properties, and at the same time reduce the weight of the structure, new materials and body concepts are being evaluated. In competition with more self-evident lightweight materials such as aluminium and plastic composites, new and different grades of high-strength steels with various surface coatings are being introduced. From experience it is known that to be able to weld and join these steel grades under high-volume conditions, it is necessary to perform comprehensive testing to establish those assembly parameters which give a superior and reliable weld quality. To meet the demands of cost-effective low volume production, we can notice a tendency to move away from traditional uni-body concepts and into the direction of space-frame structures. These can preferably be manufactured out of high-strength steels by using production methods like roll-forming, hydro-forming and hot-forming.

Heat loss is one of the greatest energy losses in engines. More than half of the heat is lost to cooling media and exhaust losses, and they thus dominate the internal combustion engine energy balance. Complex processes affect heat loss to the cylinder walls, including gas motion, spray-wall interaction and turbulence levels. The aim of this work was to experimentally compare the heat transfer characteristics of a stepped-bowl piston geometry to a conventional re-entrant diesel bowl studied previously and here used as the baseline geometry. The stepped-bowl geometry features a low surface-to-volume ratio compared to the baseline bowl, which is considered beneficial for low heat losses. Speed, load, injection pressure, swirl level, EGR rate and air/fuel ratio (λ) were varied in a multi-cylinder light duty engine operated in conventional diesel combustion (CDC) mode.

In a previous study, a passive sensor (HVAC) manikin coupled with a human thermal model was used to predict the thermal comfort of human test participants. The manikin was positioned among the test participants while they were collectively exposed to a mild transient heat up within a thermally asymmetric chamber. Ambient conditions were measured using the HVAC manikin’s distributed sensor system, which measures air velocity, air temperature, radiant heat flux, and relative humidity. These measurements were supplied as input to a human thermal model to predict thermophysiological response and subsequently thermal sensation and comfort. The model predictions were shown to accurately reproduce the group trends and the “time to comfort” at which a transition occurred from a state of thermal discomfort to comfort. In the current study, the effectiveness of using a coupled HVAC manikin-model system to evaluate a vehicle climate control system was investigated.

With the growing concern about the potential dangers with rear facing child seats placed in the front seat of passenger airbag equipped cars, various systems are being considered for deactivation of the airbag. To increase the awareness of and confidence in these proposed systems, information displays were developed for the purpose of telling the status of the passenger airbag system and to warn when necessary. A study of the effectiveness, understanding and acceptance of a selection of such information displays was jointly undertaken by Volvo Car Corporation, SAAB Automobile AB and the Swedish National Road and Transport Research Institute. Respondents of various age and demographic composition, parents and grand parents of small children, were exposed to six different sets of information displays and were asked to interpret them and also rank which information displays that would most clearly convey the message.

The objective of this paper is to investigate whether different appearance modes of the digital human models (DHM or manikins) affect the observers when judging a working posture. A case where the manikin is manually assembling a battery in the boot with help of a lifting device is used in the experiment. 16 different pictures were created and presented for the subjects. All pictures have the same background, but include a unique posture and manikin appearance combination. Four postures and four manikin appearances were used. The subjects were asked to rank the pictures after ergonomic assessment based on posture of the manikin. Subjects taking part in the study were either manufacturing engineering managers, simulation engineers or ergonomists. Results show that the different appearance modes affect the ergonomic judgment. A more realistic looking manikin is rated higher than the very same posture visualized with a less natural appearance.

This paper describes how simultaneous numerical simulation of cooling performance and aerodynamic drag can be used to achieve attribute-balanced solutions. Traditionally at Volvo, evaluation of cooling performance and aerodynamics are done by separate teams using separate models and software. However, using this approach, any project changes can be evaluated in terms of their effect on cooling performance and drag from one single model. This enables the project to make decisions that are optimal in a more global perspective. If several proposals have similar levels of cooling performance, the proposal that yields the lowest overall drag can be chosen, thus reducing the fuel consumption of the vehicle. The first part of the paper discusses the prerequisites for the method in terms of boundary conditions, mesh and solution strategy. For the cooling performance part, the importance of high quality boundary conditions is reviewed.

It is demonstrated that the cycle averaged heat flux on the hot gas side of the cylinders can be obtained using in-cylinder CFD-analysis. Together with the heat transfer coefficient obtained from the coolant jacket CFD-analysis, a complete set of boundary conditions are made available exclusively based on simulations. The engine metal temperatures could then be predicted using FEA and the results are compared to an extensive set of measured data. Also 1-D codes are used to provide cooling circuit boundary conditions and gas exchange boundary condition for the CFD-models. The predicted temperature distribution in the engine is desirable for accurate and reliable prediction of knock, durability problems, bore distortion and valve seat distortion.

Numerical simulations of the flow inside a passenger compartment are compared with experimental data obtained from velocity field measurements using Particle Image Velocimetry (PIV). Comparisons are made in the front part of the passenger compartment with the air-distribution system operated in a ventilation mode. The sensitivty of the CFD-model to the boundary conditions was investigated and two different turbulence models were tested. Computations and experiments resulted in similar results for the overall flow field, however, rather large differences were found in the vertical spreading of the jet from the dashboard nozzle. The width of the jet was lower in the measurements than in the simulations. This difference is believed to be caused by the high diffusivity obtained when using a k-epsilon model in combination with an unstructured grid.