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Car manufacturers are selling more and more different vehicles with closer and closer renewals. To achieve this, they must reduce time of development for their vehicles and powertrains. Nevertheless, this is not sufficient and it pushes into doing the race for the best quality products. Thus, longer warranty periods and lower objectives of failure rate are required for automotive components. Renault Powertrain Engineering division has developed a numerical methodology allowing to estimate this reliability, particularly for Diesel cylinder heads. This paper describes an original approach designed to validate this numerical method and based on data obtained from the field. About thirty vehicles with high mileage have been bought from private users and analyzed. The failure rate has been consequently estimated independently of any physical model. It has then been compared with assessment issued from numerical method and.

A new system reliability allocation methodology was applied on a steering product. The methodology makes use of design failure modes and effects analysis (DFMEA) and allows the allocation percentages to reflect differences in the criticality levels of the subsystems or components. The methodology was applied in conjunction with system reliability target setting. The paper first explores existing reliability allocation methods. It then introduces the new methodology. Finally, a real-life case is presented to show how the methodology was adopted and how and why it was modified. The approach presented here is one more way to make full use of the analytical efforts that have gone into the DFMEA.

Probabilistic studies can be prohibitively expensive because they require repeated finite element analyses of large models. Re-analysis methods have been proposed with the premise to estimate accurately the dynamic response of a structure after a baseline design has been modified, without recalculating the new response. Although these methods increase computational efficiency, they are still not efficient enough for probabilistic analysis of large-scale dynamic systems with low failure probabilities (less or equal to 10-3). This paper presents a methodology that uses deterministic and probabilistic re-analysis methods to generate sample points of the response. Subsequently, tail modeling is used to estimate the right tail of the response PDF and the probability of failure a highly reliable system. The methodology is demonstrated on probabilistic vibration analysis of a realistic vehicle FE model.

In reliability design, often, there is scarce data for constructing probabilistic models. It is particularly challenging to model uncertainty in variables when the type of their probability distribution is unknown. Moreover, it is expensive to estimate the upper and lower bounds of the reliability of a system involving such variables. A method for modeling uncertainty by using Polynomial Chaos Expansion is presented. The method requires specifying bounds for statistical summaries such as the first four moments and credible intervals. A constrained optimization problem, in which decision variables are the coefficients of the Polynomial Chaos Expansion approximation, is formulated and solved in order to estimate the minimum and maximum values of a system’s reliability. This problem is solved efficiently by employing a probabilistic re-analysis approach to approximate the system reliability as a function of the moments of the random variables.

ATM high pressure die casting (ATM) is a variant of the traditional high pressure die casting (HPDC) process and offers better casting quality at a lower dollar and environmental costs when compared with HPDC. The improved quality in both aluminum and magnesium alloy castings is derived from a refined microstructure in which defect-forming suspensions and pores are also refined and more homogeneously dispersed.[1-4] The higher mechanical (and potentially greater fatigue) properties provide an opportunity for reducing section thicknesses of castings, with the ultimate benefit being a reduction in the weight of the vehicle. In this article the authors describe how the introduction of an orifice-type constriction in the path of the injected melt flow results in modifications to the microstructure in ATM castings.

Task of a valve which is used in internal combustion engines is basically to help charge fresh air into combustion chamber and discharge mixture of fired fuel and air out of engine. Valve is one of the most critical parts in engine because they stand extreme temperatures, pressures and hitting impact. Because temperature which intake and exhaust valves stand is different from each other; different materials, structure and manufacturing methods are implemented on each valve. Manufacturing of the valves includes various methods such as forging, machining, welding, nitriding, coating etc. This paper explains alternative engine valve manufacturing methods, critical parameters for each manufacturing stage, potential failure modes and some corrective actions which can be taken. During study, various methods which are alternative of each other to produce engine valves were tried. Advantages & disadvantages, difficulties, failure modes and best way to correct them are recorded.

Product designers worldwide are confronted with highly competitive though conflicting demands to deliver more complex products with increased quality in ever shorter development cycles. Optimizing design performance with purely test-based approaches is no longer an option and numerical simulation methods are widely used to model, assess and improve the product design based on virtual prototypes. However, variability in design parameters and in operating conditions leads to scatter in actual performances and must be incorporated in the simulation process to guarantee the robustness of the design. This paper presents the application of state-of-the-art robust design techniques to a vehicle suspension system. A multibody model of a vehicle with a virtual test ground has been created to predict the durability response of three main components of the suspension system.

After the implementation of passive safety systems (e.g. airbags, seat belt pretensioners) and their parallel continuous improvement, active safety systems were launched in a great number of cars. Some of these active safety systems are based on environment recognition to detect critical situations or imminent crashes. These systems give warnings to the driver and can provide assistance (e.g. by setting the proper brake power). One key requirement for such systems is robust and reliable knowledge of the car environment. Today, the underlying environment recognition very often uses the data of single sensors. Due to increasing requirements in robustness, operating range (field of view, foresight, level of intervention) and number of different applications running in parallel, the fusion of data from different sensors may be necessary. This paper describes a fusion architecture which provides a base for safety and non-safety applications.

This paper proposes Prioritized-CSMA (Carrier Sense Multiple Access) protocol for Japanese vehicle safety communications (VSC). To realize Japanese VSC, we have studied a protocol to carry out Roadside-to-Vehicle (R2V) and Vehicle-to-Vehicle (V2V) communications on single channel because a single 10MHz bandwidth channel on UHF band is allocated for VSC in Japan. In this case, R2V communication requires higher quality than V2V communication, so we have developed a protocol to prevent interference between R2V and V2V communications. The proposed protocol has been evaluated by field experiments and a simulation. The results confirm that the proposed protocol prevents the interference effectively and it has capability to achieve high-quality R2V communication in actual case.

In designing vision processors for advanced automotive safety applications, the developer must address various issues, including true real-time performance and power efficiency as well as software flexibility to account for various applications, situations and environments. While parallelization through SIMD (single instruction/ multiple data) architectures has been a proven solution to speed up the initial processing of an image, SIMD processors have limited efficiency for the final image-processing steps that are mainly serialized or require floating-point arithmetic, where a MIMD (multiple instructions/multiple data) architecture would be beneficial. The paper introduces the architecture of the IMAPCAR-XC® core, a highly parallel processor that incorporates in its design the flexibility to handle all of these requirements efficiently.

In a CAS system, the distance and relative velocity between front and host vehicles are estimated to calculate time-to-collision (TTC). The distance estimates by different methods will certainly include noise which should be removed to ensure the accuracy of TTC calculations. Kalman filter is a good tool to filter such type of noise. Nevertheless, Kalman filter is a model based filter, which means a correct model is important to get the good filtering results. Usually, a vehicle is either moving with a constant velocity (CV) or constant acceleration (CA) maneuvers. This means the distance data between front and host vehicles can be described by either constant velocity or constant acceleration model. In this paper, first, CV and CA models are used to design two Kalman filters and an interacting multiple model (IMM) is used to dynamically combine the outputs from two filters.

The present automobile era in India is driven by development of small size and low cost ‘value for money’ cars. Proper utilization of space and low cost engineering of the vehicle aggregates plays a key role for attaining the goal of low cost-small cars. This paper illustrates the development of power train cooling system of such cost sensitive passenger car with rear engine and rear mounted heat exchangers. The major obstacle for the power train cooling system of rear engine-rear mounted heat exchanger (radiator) is absence of ram air effect at higher vehicle speeds and air temperatures higher then ambient, as observed for front mounted heat exchanger. The subject vehicle encountered power train cooling system failure at max speed operating condition and the project timeline required a quick solution without any major modifications and cost escalation. In case of subject vehicle because of its packaging, the air flow rate for heat exchanger was fully dependent of fan capacity.

The need for greater capacity in automotive transportation (in the midst of constrained resources) and the convergence of key technologies from multiple domains may eventually produce the emergence of a “swarm” concept of operations. The swarm, a collection of vehicles traveling at high speeds and in close proximity, will require management techniques to ensure safe, efficient, and reliable vehicle interactions. We propose a shared-autonomy approach in which the strengths of both human drivers and machines are employed in concert for this management. A fuzzy logic-based control implementation is combined with a genetic algorithm to select the shared-autonomy architecture and sensor capabilities that optimize swarm operations.

To practically apply thermoelectric technology in commercial use, improved performance in thermoelectric materials are said to be necessary in general. However, there is no frame of reference that illustrates how far away from optimal performance a material may be, nor is there any information indicating outstanding issues or possible applicable approaches that could improve system performance other than improvement in performance of thermoelectric. Application of thermoelectric in automobiles should require special design philosophy compared to general applications, but there is not enough information pointing out these special requirements.

At the forefront of intelligent vehicle technologies are vehicle-to-vehicle communication (V2V) and vehicle-infrastructure integration (VII). Their capabilities can be added to currently-available systems, such as adaptive cruise control (ACC), to drastically decrease the number and severity of collisions, to ease traffic flow, and to consequently improve fuel efficiency and environmental friendliness. There has been extensive government, industry, and academic involvement in developing these technologies. This paper explores the capabilities and challenges of vehicle-based technology and examines ways that policymakers can foster implementation at the federal, state, and local levels.

In air-cooled motorbike and stationary engines, waste heat dissipates from the cylinder through the cooling fins to the cooling air. In these engines, the cooling air flow follows the cylinder surface at the front of the cylinder, but separates at the rear, reducing cooling. To increase the distance over which the air flow follows the cylinder surface before it separates from the cylinder, and so to increase cooling at the rear, we experimented with cylinders utilizing contracted flow between fins. These cylinders have fins with different thickness at the front and the rear, so as to contract the air flow around the cylinder. We produced and tested three experimental cylinders with various lengths of contracted fins (tapered fins), in a wind tunnel at air velocities between 20 and 60km/h. We measured the temperature inside the cylinder over time to determine the heat release from the cylinder.

As global automobile manufacturers prepare for the phase-out of R134a in Europe, they must address the issue of using the new refrigerant for European sales only or launching the product worldwide. Several factors play into this decision, including cost, service, risk, customer satisfaction, capacity, efficiency, etc. This research effort addresses the minimal vehicle-level hardware differences necessary to provide a European solution of R1234yf while continuing to install R134a into vehicles for the rest of the world. It is anticipated that the same compressor, lubricant and condenser; most fluid transport lines; and in most cases the evaporator can be common between the two systems.

A common fan model to use in automotive under hood simulations is the Multiple Reference Frame (MRF) model and within the industry, for this specific application, this model is well known to under predict performance. In this paper we have examined the possibilities of correcting this deficiency with a simple “speed correction”. This is done by testing and simulating a production fan in the Volvo Fan Test Rig for two operating speeds, 1200 rpm and 2400 rpm. Pressure rise, fan power and static efficiency are presented as functions of volumetric flow rate. The simulations verify that using the MRF model the common behavior of under predicting pressure rise and performance of the fan occur. In addition, this work shows that; although the MRF is not predicting fan performance correctly it constitutes a reliable fan modeling strategy.

A novel, simple and rapid method for predicting the performance effects of blockage downstream of an automotive cooling fan is presented. Fans are often tested without downstream blockage and, thus, the performance is considerably different when the fan is mounted in a vehicle as part of a cooling system. An easy to use tool is needed that can quickly predict fan performance modifiers. The suggested approach is able to predict the significant effects of a blockage behind the fan. Two fans were analyzed with this new method. Comparison charts between tests and predictions showed good agreement over a range of blockage distances. Based on the results the method is considered beneficial for initial design procedures. Although the agreement was poorer at very close separation distances such small gaps are less commonly utilized in practice. Further work is needed to include those distances in the present model.

In recent years unsteady phenomena and turbulence environment are getting more and more important for the aerodynamic and the aeroacoustic performance of road vehicles. In this paper an investigation about Side Window Buffeting is presented. Aerodynamic and aeroacoustic measurements were carried out in Pininfarina wind tunnel both in low and high turbulence conditions. Turbulent flow has been generated by using the Turbulence Generation System (TGS). Pininfarina introduced its TGS in 2003 in order to better simulate the atmospheric and road conditions and their effects on full scale vehicles. In the present paper, the basic tool for flow field investigation is the Stereoscopic Particle Image Velocimetry probe (SPIV). Both the average and instantaneous velocity flow field in the area of the side window are measured by such a technique. The velocity maps are acquired simultaneously with pressure measurements inside the vehicle cabin.