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Frequency domain methods of analysis are now being used for the evaluation of fatigue for large vehicle systems and these methods offer advantages over equivalent time domain approaches in a number of ways, including analysis efficiency and the usefulness of derived results. One big potential advantage is to be able to do localized sub-component analysis using “cascaded” loads. Such sub-components can be analysed with refined parameters such as more sophisticated damping or a different frequency range. Local parts can also be re-analysed at a different phase in the design program. This paper will demonstrate the approach and show examples of the method.

A previous SAE paper (ref. 1) did a comparative study of automotive system fatigue models processed in the time and frequency domain. A subsequent paper (ref. 2) looked at relative random analysis under base shake loading conditions. This paper proposes to merge these two analysis procedures to implement a new “Loads Cascading” procedure. The objective of this paper will be to show how loads (accelerations, displacements, forces) can be cascaded (transferred) from input load position such as road load data (RLD) body loads to some internal location, for example a battery pack location. Also note that the response from one “module” could form the input to another, therefore, once the loadings are in the frequency domain, the possibility exists to “cascade” the loads through a system. For example, from the chassis, to the subframe to attached components.

Vehicle durability mission loads are an essential and decisive for a reliable life prediction for the component through any durability evaluation. One option to calculate mission loads are multibody models to represent vehicle’s suspension degrees of freedom (dofs) and its dynamic behavior. Generally, trucks have greater wheelbase and then lower natural frequencies than passengers’ vehicles. Therefore are more suitable to dynamic body excitation and the ordinary consideration of a rigid body shell is not relevant. The proposal of this work is to compare the chassis loads considering rigid and flexible frame mounted over the primary suspension. A pseudo-damage was calculated with chassis loads time history for severity assessment. The chose vehicle for the study is an Iveco 4×2 medium range, 6850mm of wheel base, with gross weight of 17ton and leaf springs primary suspension on both: front and rear axles.

This Paper presents the “Frequency Sweep Virtual Analysis” as a tool to help to define the best powertrain mount concept in order to identify the resonance mode frequency on Powertrain System. Applying this method, we can identify proposals to reduce loads in the Powertrain system due the resonance mode and consequently minimize possibility of exceeding material strength. The “Frequency Sweep Virtual Analysis” drives the powertrain mounts design to avoid running many Road Load Data Acquisitions (RLDA) in a trial-and-error process (Cost reduction and timing savings).

The time domain is currently the most widely chosen option in fatigue testing to fully represent random events occurring in multiple simultaneous input channels. In vehicles for example, time domain tests can represent the same conditions of the road, by applying the same loads at the hard points of the vehicle along a time history. The main drawback of this methodology is the extensive testing duration and hardware cost. Time domain based fatigue tests are composed of a complex hardware, which requires servo motors to work, in order to induce the specific amount of load at a specific time window. These tests are time consuming, since they require the same length duration of the event they are reproducing, times the required repetitions. The frequency domain method for fatigue testing, on the other hand, requires simpler hardware, since there are no need for servomotors and the test length is reduced, since there is no need to run the full event times the required repetitions.

Product design engineers have the responsibility for developing a product yielding satisfactory life for some given duty, at a reasonable cost. In the absence of an immediate failure, a product is many times subjected to loading which exceeds the design parameters, resulting in unanticipated short life and possibly poor product acceptance. Often, the ultimate user of a product, with little knowledge of the extensive effects of overloading, justifies this practice with false economics. It is the purpose of this paper to illustrate the relationship of loading to product life. With this basic understanding, it is hoped that products will be used more effectively and not abused.

The chemiluminescence emission intensity can be measured with high temporal resolution, leading to understanding the chemical reaction. Time-series chemiluminescence measurements of OH*, CH* and C2* were carried out to understand flame propagation speed, its thickness and A/F ratio of combustion status. The optical piston head (quartz) allows us to visualize combustion chamber. It is found that the chemiluminescence intensity ratio of CH*/OH* and C2*/OH* can estimate local A/F. The A/F measured by O2 sensor was used for evaluation and the results indicate this method can be applicable to estimate A/F.

The influence of variable air-fuel ratio inside a spark ignition engine is examined by the use of an ionization sensor. The measured ion currents are used for predicting the local air-fuel ratio in the vicinity of the spark plug. In order to support the results, a theoretical analysis has been made. An instationary chemical kinetic model burning a mixture of iso-octane and n-heptane is used for the calculations. The results are used to reconstruct the crank angle resolved ion current that has been measured in an engine. This technique has been developed in order to offer a supplementary low-cost facility of controlling the air-fuel ratio within the combustion chamber of an engine.

This paper describes a numerical study of the effect of hollow crankshafts on crankshaft local strength and durability as well as slider bearing contact behavior. Crankshaft dynamic simulation for durability is still a challenging task, although numerical methods are already worldwide established and integrated part of nearly every standard engine development process. Such standard methods are based on flexible multi-body dynamic simulation, combined with Finite Element analysis and multi-axial fatigue evaluation. They use different levels of simplification and consider the most influencing phenomena relevant for durability. Lightweight design and downsizing require more and more detailed methods due to higher deformation of the crankshaft. This is especially true for hollow shafts, as present in motorsport design or aerospace applications, but also for standard engine having high potential for significant weight savings.

The paper presents the view of a major manufacturer of Automotive electricals and electronics. It shows this industry as part of the Australian environment, how it fits into the global automotive scene and points out where our challenges lie. The capabilities of the industry in the R&D field as well as the application Engineering areas are explained. On the manufacturing side, an overview of the state of the art of producing electronic control modules is provided. The approaches and equipment selected in Australia, as governed by manufacturing volumes and economics, are described. An important aspect is the link between the highly sophisticated manufacturing processes and equipment on one hand and quality assurance and reliability on the other. The paper closes with an outlook towards future electronic systems expected to be used in Australia.

Automobile fires account for the majority of vehicle fires and vehicle fire deaths. Fires involving larger trucks resulted in a disproportionate share of vehicle fire losses. Although bus fires are less common, they have a much higher rate of fire based on distance driven. Bus fires have the potential to endanger a larger number of passengers. Any efforts to evaluate the merits of proposed fire safety improvements require an understanding of how many fires and deaths are presently occurring and how many might be prevented with the proposed improvements. Data from the U.S. Fire Administration's National Fire Incident Reporting System (NFIRS) and the National Fire Protection Association's (NFPA's) fire department survey were used to estimate the frequency and associated losses of such fires attended by local U.S. fire departments, and the major factors in these fires and losses.

We present an experimental investigation of the local flame front characteristics as function of the distance between the flame front and the piston. The objective of this paper is to provide some experimental data about the flame characteristics at the approach of the piston. The transparent engine speed is fixed at 2000 rpm and air-methane mixture was used with an equivalence ratio equal to 0.9. PLIF acetone imaging was acquired to estimate first the curvature, the curvature radius and the normal direction orientation of the local contours as function of the flame-piston distance. A discontinuity in these parameters appears when the distance is less than 1 mm. Secondly we apply local roughness analysis system to estimate the local fractal dimension of the flame front. We conclude that fractal dimension changes rapidly at 2.5 mm from the piston. A logarithm law was found to define the fractal dimension as function of flame-piston distance.

A local Gaussian process regression approach is presented, which allows to model nonlinearities of internal combustion engines more accurate than global Gaussian process regression. By building smaller models, the prediction of local system behavior improves significantly. In order to predict a value, the algorithm chooses the nearest training points. The number of chosen training points depends on the intensity of estimated nonlinearity. After determining the training points, a model is built, the prediction performed and the model discarded. The approach is demonstrated with a benchmark system and air charge test bed measurements. The measurements are taken from a turbocharged SI gasoline engine with both variable inlet valve lift and variable inlet and exhaust valve opening angle. The results show how local Gaussian process regression outmatches global Gaussian process regression concerning model quality and nonlinearities in particular.

Instantaneous local heat transfer coefficients on the wall surface of combustion chamber were estimated experimentally using a four cycle, L-type, single cylinder, spark-ignition engine. The effects of gas flow and flame propagation on the heat transfer coefficients were investigated. Local heat flux was measured at twenty four positions on the cylinder head using a fast-response heat flux sensor developed by the authors, and the pressure in the combustion chamber was measured simultaneously. The burned- and unburned gas temperatures were calculated from a two-zone model. The flame arrival time at a position of cylinder head surface was also measured and flame velocity was calculated. The results showed that the maximum heat flux decreases as the flame arrival time increases. An empirical correlation between Nusselt number based on the local heat transfer coefficient and Reynolds number based on the flame velocity is derived from the experimental investigation of spark-ignition engine.

The influence of elevated temperature forming on local mechanical properties of AZ31B magnesium (Mg) sheet material was investigated. The Mg sheet was formed into a closure component with high temperature gas pressure at 485°C. Miniature tensile testing specimens were cut from selected areas of the component where different levels of thinning occurred. The specimens were strained in tension to fracture using a miniature tensile stage. The two-dimensional strain distribution in the necking region along with true stress-true strain curves were computed using a digital image correlation technique to assess the influence of the forming-induced thinning on tensile strength and percent elongation at fracture.

Over the years, internal combustion engines have been researched and improved in the search for more power and for lower fuel consumption. An automotive subsystem that directly affects the performance of the engine is the valve train system. This system allows for the control of the admittance and release of gases from the combustion chamber. This system operates in all phases, ensuring that the valves open and close properly and ensuring the sealing of the cylinder. Several researchers have studied the kinematics and dynamics of the valve actuation system to improve engine performance. As the actuation of the valves occurs usually by cams, every movement and timing of the system is dictated by the design characteristics of the profile of the cams: it has a predominant action on the dynamics of the system.

In autonomous driving, variations in tire vertical load, tire slip angle, road conditions, tire pressure and tire friction all contribute to uncertainty in tire cornering stiffness. Even the same tire may vary slightly during the manufacturing process. Therefore, the uncertainty of tire cornering stiffness has an important influence for autonomous driving path planning and control strategies. In this paper, the Chebyshev interval method is used to represent the uncertainty of tire cornering stiffness and is combined with a model predictive control algorithm to obtain the trajectory interval bands under local path planning and tracking control. The accuracy of the tire cornering stiffness model and the path tracking efficiency are verified by comparing with the path planning and control results without considering the corner stiffness uncertainties.

Local path planning for obstacle avoidance is one of the core topics of intelligent vehicle. A novel method based on dubins curve and tentacle algorithm is proposed in this article, with the consideration of obstacle avoidance and vehicle motion constraints. First, the preview distance of the vehicle is given according to the current speed, so that the preview point can be found with the information of global path. Then dubins curve is adopted to find a path with appropriate turning radius, between the current position and preview point, satisfying the constraints of current direction and target direction, considering handling and ride comfort of the vehicle. In order to avoid obstacle, tentacle algorithm is adopted. 20 tentacle points are given by moving the original preview point, and then 21 local paths can be given by using dubins curve. Cost function is used to find out the best option of the 21 paths.

Dense depth estimation is a critical application in the field of robotics and machine vision where the depth perception is essential. Unlike traditional approaches which use expensive sensors such as LiDAR (Light Detection and Ranging) devices or stereo camera setup, the proposed approach for depth estimation uses a single camera mounted on a rotating platform. This proposed setup is an effective replacement to usage of multiple cameras, which provide around view information required for some operations in the domain of autonomous vehicles and robots. Dense depth estimation of local scene is performed using the proposed setup. This is a novel, however challenging task because baseline distance between camera positions inversely affect common regions between images. The proposed work involves dense two view reconstruction and depth map merging to obtain a reliable large dense depth map.

Local strain measurement based on digital image correlation at both macroscopic and microscopic scales is presented. A speckle pattern was used for the macroscopic strain mapping to reveal the inhomogeneous deformation processes occurring during tensile deformation of a strip cast automotive aluminum sheet. Moreover, a novel microscopic strain mapping technique based on scanning electron microscopic (SEM) topography image correlation was introduced for strain mapping down to the grain level. The SEM images taken from an in-situ tensile sample of the same material within a field emission SEM chamber are used to demonstrate the validity of the method. The results clearly reveal the evolution of local strain of order of one as well as the formation of shear band in the material.