Search Results

Extended drain of axle and transmission lubricants has gained wide acceptance in both passenger car and commercial vehicle applications. Understanding how the lubricant changes during extended drain operations is crucial in determining appropriate lubricants and drain intervals for these applications. A suitable aging screen test with an established relationship to field performance is essential. Over the years numerous methods have been studied (DKA, GFC, ISOT, ASTM L-60) with varying degrees of success1,2,3. Current methods tend to be overly severe in comparison to field experience, hence the need for further work in this area. As a result of recent work, a lubricant aging test method has been developed which shows good correlation with field experience, giving us an effective tool in the development of long drain oils.

Safety is becoming more and more important with the ever increasing level of safety related E/E Systems built into the cars. Increasing functionality of vehicle systems through electrification of power train and autonomous driving leads to complexity in designing system, hardware, software and safety architecture. The application of multicore processors in the automotive industry is becoming necessary because of the needs for more processing power, more memory and higher safety requirements. Therefore it is necessary to investigate the safety solutions particularly for Automotive Safety Integrity Level (ASIL-D) Systems. This brings additional challenges because of additional requirements of ISO 26262 for ASIL-D safety concepts. This paper presents an approach for model-based “dependent failure analysis” which is required from ISO 26262 for ASIL-D safety concepts with decomposition approach.

Increasing requirements for comfort and lightweight design lead to higher acoustic target values for passenger car components, especially for automatic transmissions. The required increase of the acoustic tooth-mesh quality reduces the masking of tonal noises that are often the failure cause at the EOL test bench. Based on the mathematic transmission model that includes all orders and moments that are acoustically relevant, a database-based dynamic website supports the engineer with the localization of disturbing noises. After that, irregularities are extracted from the order spectra and are provided for the evaluation tool. A special search algorithm depicts all possible failure causes. On the one hand, refined entries allow the limitation of the solution sets; on the other hand, experience help to limit the solutions to acoustically relevant disturbance mechanisms.

In view of legal requirements and measures for climate protection, fuel efficient vehicles have become increasingly important. Against this background, transmissions are a key factor for two main reasons: Energy consumption and emissions can be reduced by optimization of conventional transmissions. The "ideal" transmission has a potential of contributing to this goal by about 10%. Between 4 and 5% out of this 10% can realistically be achieved. Driveline electrification constitutes another necessary step for CO₂ savings. To this end, an ideal option is integrating the electric components into the transmission. In view of the uncertain market development for hybrid car demand, a modular approach to electrification in transmissions is essential. This article outlines the electrification approach.

As we move towards greener technologies in the transportation sector, it becomes mandatory to monitor its impact or the utilization of such a technology in the intended manner. Improper usage results in lesser utilization of benefits of such green technologies. One such scenario is the range anxiety; users of parallel hybrid vehicles face a dilemma between charging and refueling the vehicle. If the hybrid vehicle is operated in a gas-powered mode most of the time, the emission levels would be comparable to those of gas-powered vehicles. On the other hand, gas-powered vehicles have no mechanism to completely cut CO2 emissions, unlike hybrids (electric drive). Emission regulatory bodies are facing difficulties in regulating each road vehicle. Therefore, the actual emission levels emitted from the vehicles are higher than the estimate provided by regulations. This paper discusses the possibility of implementing a Carbon Credit Scoring for each class of vehicles.

In recent years the automotive companies are developing their self-driving technology very rapidly. Most of them want to launch their self-driving vehicles with SAE level 4 at the beginning of 2020. The main goal of the development of self-driving cars is to reduce accidents caused by driver errors. But there are some technological challenges to solve such as increasing of the safety and availability in order to get the acceptance from the customers. The purpose of this research is to investigate the possible fail-operational safety architectures for both conventional systems as powertrain and the entire ADAS processing chain.

This paper describes the ZF - Intarder, a wear-free vehicle brake for commercial vehicles. Qualities such as optimum weight saving, compactness, compatibility with all PTOs and no change in driveshaft length, are the results of a new development. Performance measurements demonstrate connection with engine cooling system. Field test measurements provide new information about frequency of use of various brake levels and electronic speed control. An evaluation of financial issues indicates advantages for operation.

Modern commercial vehicles must increasingly meet the requirements of economic efficiency, environmental protection, legislation and of the specific application. The Electronically-Controlled Rear Axle Steering System ZF RAS-EC™ makes an important contribution towards this and offers a basis for completely new approaches in the development of commercial vehicles.

With the rapid development of connected and autonomous vehicles, more sophisticated automotive systems running large portions of software and implementing a variety of communication interfaces are being developed. The ever-expanding codebase increases the risk for software vulnerabilities, while at the same time the large number of communication interfaces make the systems more susceptible to be targeted by attackers. As such, it is of utmost importance for automotive organizations to identify potential vulnerabilities early and continuously in the development lifecycle in an automated manner. In this paper, we suggest a practical approach for integrating fuzz testing into a Continuous Integration (CI) pipeline for automotive systems. As a first step, we have performed a Threat Analysis and Risk Assessment (TARA) of a general E/E architecture to identify high-risk interfaces and functions.

Sensing and acting elements to guarantee the locking functions of seat belt retractors can emit noise when the retractor is subjected to externally applied vibrations. For these elements to function correctly, stiffness, inertia and friction needs to be in tune, leading to a complex motion resistance behavior, which makes it delicate to test for vibration induced noise. Requirements for a noise test are simplicity, robustness, repeatability, and independence of laboratory and test equipment. This paper reports on joint development activities for an alternative test procedure, involving three test laboratories with different equipment. In vehicle observation on parcel shelf mounted retractors, commercially available test equipment, and recent results from multi-axial component tests [1], set the frame for this work. Robustness and reliability of test results is being analyzed by means of sensitivity studies on several test parameters.

Modern vehicles are driven with various speeds over specific rough road tracks to detect the presence of annoying buzz, squeak and rattle sounds. As known in the occupant safety industry the mechanical locking systems of seat belt retractors can be significant noise sources, when excited by road vibrations. A reliable bench test procedure is necessary to quantify the acoustic performance of retractors, verify production quality, and derive realistic acoustic product targets. With this goal, a vibration noise test procedure has been developed condensing the work over three years by the K2 Comet automotive research project X2T1, various OEM retractor noise specifications closed to public and own research. The load case in this specification has been defined as horizontal 60 Hz bandlimited broadband excitation, while the N10 instationary loudness metric has been selected to characterize the retractor acoustic performance.

Seatbelt retractors as important part of modern safety systems are mounted in any automotive vehicle. Their internal locking mechanism is based on mechanically sensing elements. When the vehicle is run over rough road tracks, the retractor oscillates by spatial mode shapes and its interior components are subjected to vibrations in all 6 degrees of freedoms (DOF). Functional backlash of sensing elements cause impacts with neighbouring parts and leads to weak, but persistent rattle sound, being often rated acoustically annoying in the vehicle. Current acoustic retractor bench tests use exclusively uni-directional excitations. Therefore, a silent 2 DOF test bench is developed to investigate the effect of multi-dimensional excitation on retractor acoustics, combining two slip-tables, each driven independently by a shaker. Tests on this prototype test bench show, that cross coupling between the two perpendicular directions is less than 1%, allowing to control both directions independently.

Variable Damping systems for commercial vehicle applications have been in the market for several years now. The systems modify damping according to the actual demand within milliseconds. This reduces vertical accelerations which lead to improved comfort while maintaining vehicle stability and safety at the same time. Driver, cargo and vehicle are better protected. The technical effort for variable damping systems was in the past rather high and affected a limited market penetration. On the other side the used control algorithms did not tap the full potential of the system performance. New concepts, like integration of sensors or concentration on the most relevant axle, in combination with new control algorithms, simplifies the systems architecture and improves the performance. Besides the functional advantages, the system improves vehicle efficiency as it reduces the energy dissipated by the dampers. This energy would have to be generated by the engine.

Market trends clearly demonstrate the ongoing worldwide acceptance and success of modern automatic transmission solutions (AT, CVT, DCT) in both passenger cars and light trucks. This success is based on the further development of the driving comfort, shifting dynamics and - most important - the fuel consumption reduction modern automatic transmission systems offer. First, key driveline parameters such as overall spread and number of ratio's are to be discussed. The optimum spread for the fuel efficiency is in the range of about 8 to 9 and can typically be achieved by 8 to 10-speed transmissions. This is because modern gasoline or diesel-engines have a rather flat characteristic fuel map. Therefore the inner efficiency of the future transmissions becomes increasingly important.

Automotive systems have become increasingly more complex, interconnected and prone to cyberattacks in recent years. With larger software bases and multiple external communication interfaces, the risks for new vulnerabilities and attack vectors on vehicles also increase. Therefore, modern cybersecurity validation is highly stressed for finding security vulnerabilities and robustness issues early and systematically at every stage of the product development process. The integration of a sophisticated fuzz testing program within the overall cybersecurity validation strategy allows for accommodating towards these challenging demands. In this paper, we review a general automotive cybersecurity engineering process containing functional testing, vulnerability scanning and penetration testing, and highlight shortcomings that can be complemented by fuzz testing.

Pneumatic valves are widely used in heavy commercial vehicles’ air braking systems. These valves are mainly used in the braking system layout to maintain the vehicle stability during dynamic conditions. Rubber components are inevitable in valves as a sealing element, and it is very difficult to predict the behavior due to its nonlinear nature. Basically, this valve efficiency is defined in terms of performance and response characteristics. These characteristics are determined in the concept stage itself using 1D simulation software. AMESim software has a variety of elements to use in a unique way for performance and response behavior prediction. For pneumatic valves, 1D analysis is an effective method and it gives good correlation with actual test results. During the modelling of pneumatic valves, some of the contacts between rubber and metals are controlled by various parameters such as damping, contact stiffness and desired phase angle.

Electric vehicles (EV) require an electric motor with a better power density, greater efficiency, a wide constant power area, ease of control, and low costs. A real time control adapted electric motor design is necessary to meet these criteria. In this work, interior permanent magnet synchronous motor (IPMSM) design was created from Ansys rotating machine expert and 2D model was developed in Ansys Maxwell based on various design parameters for the rotor and stator configuration, and the electromagnetic (EM) simulations are carried out in accordance with the essential required EV characteristics. Using Ansys Twin Builder, a model was made for the drive circuit, proportional integral (PI) speed controller, speed references, rotor position detection, and space vector pulse width modulation (SVPWM) / sinusoidal pulse width modulation (SPWM) are used.

Under the name “ZF ECOnnect”, ZF has recently developed a variety of AWD driveline solutions with an available AWD disconnect function. The ZF AWD disconnect systems are mainly designed for FWD-based AWD architectures and greatly help to solve the conflict between AWD performance the additional fuel consumption caused by AWD in comparison to FWD. AWD disconnect means that when no AWD function is required, there will be no torque transfer to the secondary axle. Therefore, the speed-dependent losses due to friction and oil churning are avoided by bringing the normally rotating elements to a standstill, while the vehicle is still driving. Compared to a conventional hang-on AWD system, the disconnect system therefore reduces the friction losses in the AWD driveline by up to 90% in the disconnected mode. This is achieved by the overall design of the units including special features and optimized coupling elements resulting in very low drag torque.

The automotive industry continues to focus heavily on new electrified mobility strategies. Whether this electrified mobility consists of battery electric vehicles or electrified brake boost systems, there is a level of system sensitivity which presents new challenges throughout the industry during development of a new product. Most specifically in brake system development, much of the critical performance targets that have come along with electrification are cascaded down to the vehicle corner and its component performance. These corner level requirements have transformed to be more stringent in order to improve the overall system efficiency. It is important that the factors which lead to less than desirable performance are identified and understood. Some of the factors that influence the brake system corner performance are driven by multiple components, and this paper will go into identifying & explaining the following.