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Most OEMs are shifting their strategy and way of thinking regarding ECUs. This, in combination with the electrification of vehicles and the shift towards software-based companies (car as a device), implies one of the biggest paradigm changes in automotive history. On the other hand, despite the current struggles, remarkable advances have been made in electronic technology during the past few years. These developments have opened a door to very promising enabling technology, with exterior lighting as a main target market. These circumstances seem to have created a perfect storm leading to new strategies for electronic control and driving for (front and rear) exterior lighting. We, at our company, have investigated the enabling technology, challenges, and benefits of this emerging exterior lighting approach, that we call ‘ECU-Less’.

The aim of the presented research is to propose and benchmark two brake models, namely the novel dynamic ILVO (Ilmenau-Volvo) model and a neural-network based regression. These can estimate the evolution of the brake friction between pad and disc under different load conditions, which are typically experienced in vehicle applications. The research also aims improving the knowledge of the underlying mechanism related to the evolution of the BLFC (boundary layer friction coefficient), the reliability of virtual environment simulations to speed up the product development time and reducing the amount of vehicle test in later phases and finally improving brake control functions. With the support of extensive brake dynamometer testing, the proposed models are benchmarked against State-of-the-Art. Both approaches are parametrized to render the friction coefficient dynamics with respect to the same input parameters.

Audio CAE is an emerging area of interest for vehicle OEMs. Questions regarding early stages of the vehicle design, like choosing the possible positions for speakers, deciding the installation details that can influence the visual design, and integration of the low frequency speakers with the body & closures structure, are of interest. Therefore, at VCC, the development of the CAE methodology for audio applications has been undertaken. The key to all CAE applications is the loudspeaker model made available in the vibro-acoustic software used within the company. Such a model has been developed, implemented and verified in different frequency ranges and different applications. The applications can be divided into the low frequency ones (concerning the installation of woofers and subwoofers), and the middle/high frequency ones (concerning the installation of midrange and tweeter speakers). In the case of the woofer, it is the interaction with the body vibration that is of interest.

Existing battery parameter model structures are evaluated by estimating model parameters on real driving data applying standard system identification methods. Models are then evaluated on the test data in terms of goodness of fit and RMSE in voltage predictions. This is different from previous battery model evaluations where a common approach is to train parameters using standardized tests, e.g. hybrid pulse-power capability (HPPC), with predetermined charge and discharge sequences. Equivalent linear circuit models of different complexity were tested and evaluated in order to identify parameter dependencies at different state of charge levels and temperatures. Models are then used to create voltage output given a current, state of charge and temperature. The average accuracy of modelling the DC bus voltage provides a model goodness of fit average higher than 90% for a single RC circuit model.

Vehicle dynamics development relies on subjective assessments (SA), which is a resource-intensive procedure requiring both expert drivers and vehicles. Furthermore, development projects becoming shorter and more complex, and increasing demands on quality require higher efficiency. Most research in this area has focused on moving from physical to virtual testing. However, SA remains the central method. Less attention has been given to provide better tools for the SA process itself. One promising approach is to introduce computer-tablets to aid data collection, which has proven to be useful in medical studies. Simple software solutions can eliminate the need to transcribe data and generate more flexible and better maintainable questionnaires. Tablets’ technical features envision promising enhancements of SA, which also enable better correlations to objective metrics, a requirement to improve CAE evaluations.

In areas such as Active Safety, new technologies, designs (e.g. AUTOSAR) and methods are introduced at a rapid pace. To address the new demands, and also requirements on Functional Safety imposed by ISO 26262, the support for engineering methods, including tools and data management, needs to evolve as well. Generic and file-based data management tools, like spreadsheet tools, are popular in the industry due to their flexibility and legacy in the industry but provide poor control and traceability, while rigid and special-purpose tools provide structure and control of data but with limited evolvability. As organizations become agile, the need for flexible data management increases. Since products become more complex and developed in larger and distributed teams, the need for more unified, controlled, and consistent data increases.

When it comes to the acoustic properties of electric cars, the powertrain noise differs dramatically compared to traditional vehicles with internal combustion engines. The low frequency firing orders, mechanical and combustion noise are exchanged with a more high frequency whining signature due to electromagnetic forces and gear meshing, lower in level but subject to annoyance. Previous studies have highlighted these differences and also investigated relevant perception criteria in terms of psycho-acoustic metrics. However, investigations of differences between different kinds of electric and hybrid electric cars are still rare. The purpose of this paper was to present the distribution of tonal components in today's hybrid/electric vehicles. More specifically, the number of prominent orders, their maximum levels and frequency separation were analyzed for the most critical driving conditions. The study is based upon measurements made on 13 electrified cars on the market.

Current trends for IC-engines are driving the development of more efficient engines with higher specific power. This is true for both light and heavy duty vehicles and has led to an increased use of super-charging. The super-charging can be both in the form of a single or multi-stage turbo-charger driven by exhaust gases, or via a directly driven compressor. In both cases a possible noise problem can be a strong Blade Passing Frequency (BPF) typically in the kHz range and above the plane wave range. In this paper a novel type of compact dissipative silencer developed especially to handle this type of problem is described and optimized. The silencer is based on a combination of a micro-perforated (MPP) tube backed by a locally reacting cavity. The combined impedance of micro-perforate and cavity is chosen to match the theoretical optimum known as the Cremer impedance at the mid-frequency in the frequency range of interest.

With the increase in fuel prices and the increasingly strict environmental legislations regarding CO₂ emissions, reduction of the total energy consumption of our society becomes more important. Passenger vehicles are partly responsible for this consumption due to their strong presence in the daily life of most people. Therefore reducing the impact of cars on the environment can assist in decreasing the overall energy consumption. Even though several fields have an impact on a passenger car's performance, this paper will focus on the aerodynamic part and more specifically, the wake behind a vehicle. By definition a car is a bluff body on which the air resistance is for the most part driven by pressure drag. This is caused by the wake these bodies create. Therefore analyzing the wake characteristics behind a vehicle is crucial if one would like to reduce drag.

Automotive turbo compressors generate high frequency noise in the air intake system. This sound generation is of importance for the perceived sound quality of luxury cars and may need to be controlled by the use of silencers. The silencers usually contain resonators with slits, perforates and cavities. The purpose of the present work is to develop acoustic models for these resonators where relevant effects such as the effect of a realistic mean flow on losses and 3D effects are considered. An experimental campaign has been performed where the two-port matrices and transmission loss of sample resonators have been measured without flow and for two different mean flow speeds. Models for two resonators have been developed using 1D linear acoustic theory and a FEM code (COMSOL Multi-physics). For some resonators a separate linear 1D Matlab code has also been developed.

An acoustic one-dimensional compressor model has been developed. This model is based on compressor map information and it is able to predict how the pressure waves are transmitted and reflected by the compressor. This is later on necessary to predict radiated noise at the intake orifice. The fluid-dynamic behavior of the compressor has been reproduced by simplifying the real geometry in zero-dimensional and one-dimensional elements with acoustic purposes. These elements are responsible for attenuating or reflecting the pressure pulses generated by the engine. In order to compensate the effect of these elements in the mean flow variables, the model uses a corrected compressor map. Despite of the fact that the compressor model was developed originally as a part of the OpenWAM™ software, it can be exported to other commercial wave action models. An example is provided of exporting the described model to GT-Power™.

Maintaining the current ratio between certified and the customer-observed fuel consumption even with future required levels poses a considerable challenge. Increasing the efficiency of the driveline enables certified fuel consumption down to a feasible level in the order of 80 g CO₂/km using fossil fuels. Mainly affecting off-cycle fuel consumption, energy amounts used to create good interior climate as well as energy-consuming options and features threaten to further increase. Progressing urbanization will lead to decreasing average vehicle speeds and driving distances. Highly efficient powertrains come with decreased amounts of waste energy traditionally used for interior climate conditioning, thus making necessary a change of auxiliary systems.

Future demands for improvements in the fuel economy of gasoline passenger car engines will require the development and implementation of advanced combustion strategies, to replace, or combine with the conventional spark ignition strategy. One possible strategy is homogeneous charge compression ignition (HCCI) achieved using negative valve overlap (NVO). However, several issues need to be addressed before this combustion strategy can be fully implemented in a production vehicle, one being to increase the upper load limit. One constraint at high loads is the combustion becoming too rapid, leading to excessive pressure-rise rates and large pressure fluctuations (ringing), causing noise. In this work, efforts were made to reduce these pressure fluctuations by using a late injection during the later part of the compression. A more appropriate acronym than HCCI for such combustion is SCCI (Stratified Charge Compression Ignition).

The development of a new combustion system for a light-duty diesel engine is presented. The soot-NOx trade-off is significantly improved with maintained or improved efficiency. This is accomplished only by altering the combustion chamber geometry, and thereby the in-cylinder flow. The bowl geometry is developed in CFD and validated in single cylinder tests. Tests and simulations align remarkably well. Under identical conditions in the engine the new combustion chamber decreases smoke by 11-27%, NOx by 2-11%, and maintains efficiency as compared to the baseline geometry. The injector nozzle is matched to the new bowl using design of experiments (DoE). By this method transfer functions are obtained that can be used to optimize the system using analytical tools. The emissions show a complex dependence on the nozzle geometry. The emission dependence on nozzle geometry varies greatly over the engine operating range.

Automotive electronic systems are becoming safety related causing a need for more systematic and stringent approaches for demonstrating the functional safety. The safety case consists of an argumentation, supported by evidence, of why the system is safe to operate in a given context. It is dependent on referencing and aggregating information which is part of the EAST-ADL2, an architecture description language for automotive embedded systems. This paper explores the possibilities of integrating the safety case metamodel with the EAST-ADL2, enabling safety case development in close connection to the system model. This is done by including a safety case object in EAST-ADL2, and defining the external and internal relations.

Ion current sensors have high potential utility for obtaining feedback signals directly from the combustion chamber in internal combustion engines. This paper describes experiments performed in a single-cylinder optical engine operated in HCCI mode with negative valve overlap to explore this potential. A high-speed CCD camera was used to visualize the combustion progress in the cylinder, and the photographs obtained were compared with the ion current signals. The optical data indicate that the ions responsible for the chemiluminescence from the HCCI combustion have to be in contact with the sensing electrode for an ion current to start flowing through the measurement circuit. This also means that there will be an offset between the time at which 50% of the fuel mass has burned and 50% of the ion current peak value is reached, which is readily explained by the results presented in the paper.

Volvo Car Corporation has developed a Reference Architecture for PAG1 Infotainment Systems. A Reference Architecture is an architecture scoping over more than a single system, i.e. an architecture aimed for a family of systems. The Infotainment Reference Architecture has since 2001 been successfully applied for the PAG family which so far covers the infotainment systems of Volvo XC90, Volvo S40/V50, Jaguar XK, Aston Martin DB9 and the brand new Volvo S80. In 1999, the system design departments started up with the clear objective to develop a system solution aiming for the PAG infotainment system family. The work was carried out according to the established development process at Volvo Cars. A year later a discouraging design review was performed. The number of involved functions, the level of function interaction and the distribution of functionalities between ECUs resulted in a non-manageable system solution.

Galvanic corrosion between die cast AZ91D and AM60B and different fastener systems has been evaluated by exposure on trucks and in accelerated laboratory tests. The exposure time on the trucks was 3 years, corresponding to a mileage of about 300000 km. Samples were retracted and evaluated after 1 and 2 years exposure. Similar samples were also exposed to the Volvo Indoor Corrosion Test and the General Motors GM9540P-cycle B test. The correlation between the field data and the laboratory tests was evaluated, as was the sharp difference in the performance of the fastener systems in the two accelerated laboratory tests.

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.

A single-cylinder engine was operated in HCCI combustion mode with different kinds of commercial fuels. The HCCI combustion was generated by creating a negative valve overlap (early exhaust valve closing combined with late intake valve opening) thus trapping a large amount of residuals (∼ 55%). Fifteen different fuels with high octane numbers were tested six of which were primary reference fuels (PRF's) and nine were commercial fuels or reference fuels. The engine was operated at constant operational parameters (speed/load, valve timing and equivalence ratio, intake air temperature, compression ratio, etc.) changing only the fuel type while the engine was running. Changing the fuel affected the auto-ignition timing, represented by the 50% mass fraction burned location (CA50). However these changes were not consistent with the classical RON and MON numbers, which are measures of the knock resistance of the fuel. Indeed, no correlation was found between CA50 and the RON or MON numbers.