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The aim of this research was to analyze the lubrication conditions of piston pin boss bearings used in the press-fit piston pins of automobile gasoline engines. An original pin boss friction measuring device was developed and used to successfully obtain measurements. It was revealed that the friction force peaks twice every cycle at high engine loads, and non-fluid lubrication characteristics are displayed. The friction forces for various differing piston pins and pin boss bearings were analyzed, and it was shown that reducing piston pin length or thickness to reduce piston weight, or reducing the pin boss bearing clearance to reduce noise worsen the friction characteristics and increase the possibility of abnormal bearing friction as well as seizure.

Vehicle breakdown statistics show a clear trend: quality will be a major target for the future. This, taken together with the growing market demand for greater reliability, shows that the automobile industry needs to take action. A way to achieve this is being sought, in some cases too frantically. All the concepts which have been formulated, as yet, have a common aim: Price or cost reduction A more flexible response to market trends To boost the consumer's quality consciousness. The right response to these challenges leads directly to a reduction in development time. The first answer is a standardization of test procedures according to operating strength. The first idea and outlook was done in the SAE-Paper 790464 in 1979: “The ASSET-Technique”. Now in 1996 it has become a standard in the German car industry. [1]

A new approach to cope with the disadvantages of the self energizing drum brake by means of mechatronics is described. The introduced system allows for control of the brake factor of a duplex drum brake from C*=2 to C*=6. Variations of the friction factor μ due to fading will be compensated to a certain extent using an electronically controlled mechanism adjusting the support base of the leading shoes of the brake. The required application forces are up to seven times lower compared to a disk brake at equal braking torques. Theory, design and measurements of a prototype brake with mechatronically controlled self energizing are the topics of this paper. The described research work was carried out at the Department of Automotive Engineering (fzd) of the University of Darmstadt.

We have developed a new type of system to prevent disc brake squealing. The rotor vibration radiates the squeal noise, therefore if the rotor vibration can be stopped electronically, no squeal is generated. Based on this concept, the Electronic Control Canceling System for a Disc Brake Noise ( ECCN ) was developed for the opposed type brake which has four brake pistons. The ECCN consists of four piezoelectric elements and one electronic control unit, and can stop the low-frequency squeal of 2∼4kHz by using a small amount of energy with the noise dynamometer and the test vehicle.

It is said that the disc brake squeal is the noise caused by the friction-induced vibration between pads and rotor, by which the brake assembly resonates. In this paper, the forces on the pads and the accelerations of the brake were measured, and their results were discussed by the correlation of them. As a result, the forces acting on the pad were observed to vibrate at low cycle synchronizing with the revolution of rotor. And the friction coefficient curve indicates several parts of negative gradient and periodicity. This phenomenon was well correlated with the mechanism of the excitation of brake squeal vibration by the simulation result.

Air flow around the front brake assembly was computed using STAR-CD version 2.300, a commercial Computational Fluid Dynamics (CFD) code in order to explore the possibility of using this technique as a design tool. The primary objective in a brake corner assembly design is to maximize air cooling of the brake rotor. It is a very challenging task that requires experiments that are both expensive and time consuming in order to evaluate and optimize the various design possibilities. In this study, it is demonstrated that the design procedure can be shortened and made less expensive and be accurate using flow simulations. Accordingly, the air flow around the front brake assembly was computed for three different designs and for three different car speeds. A computational mesh was built using PROSTAR, the STAR-CD pre and post-processor. The three-dimensional mesh had almost 900,000 cells. All geometrical components were modelled.

The temperature influences significantly the braking effectiveness. The paper describes consistency criterions of the brake thermal state in road braking conditions and on the roll-stand. As a result of the vehicle motion simulation, the time histories of the heat fluxes generated on the friction surface of the front and rear disc were determined. They were used as an input data for the model of the heat transfer process in disc brakes. The problem was solved by the use of the finite element method. Time histories of temperatures on the friction surfaces and in the material of the disc were calculated. As a preliminary consistency criterion of the brake thermal state in road and roll-stand braking conditions, a balance of the energy cumulated in the brake rotor was assumed. As the most reliable consistency criterion an equality of average temperatures of the friction surface was assumed.

In side-crash phenomena, finite element modeling is essential in investigating the occupant's post-impact dynamic behavior after contact with the door panels. A number of modifications have been made to the model described here based on combined simulation and experimental verifications of the dynamic and pseudo-static characteristics of different materials such as foam, damper and individual sub-assemblies. This report illustrates how the modified material and structural modeling of different components improve the accuracy of the overall dynamic behavior of the FEM model in simulating different HYGE experiments to speed up and optimize the vehicle design process. The rib-module drop test results with two different polypropylene pads clearly indicate the effect of the pad unloading characteristics on rib displacement.

Currently, the three (3) methods for calculating the HIC-value are: 1) direct computation method, 2) utilization of maximization requirement approach developed by Chou and Nyquist, and 3) a partitioning technique. A method which involves the adoption of an optimization approach for HIC calculation is discussed in this study. This optimization technique, which has previously been applied to Boundary Element Method (BEM), employs an improved constrained variable metric method in recursive quadratic programming. This technique was applied to three theoretical and ten experimental acceleration pulses; the results compare extremely well with exact solution and/or other numerical methods. It is concluded that this optimization scheme provides accurate HIC calculations. A study is planned to investigate the feasibility of extending the application of this optimization technique to an integrated trim/foam/sheet metal pillar system for improved interior head impact protection study.

Occupant simulation models have been used to study trends or specific design changes in “typical” accident modes such as frontal, side, rear, and rollover. This paper explores the usage of the Articulated Total Body Program (ATB) as an accident reconstruction tool. The importance of model validation is discussed. Specific areas of concern such as the contact model, force-deflection data, occupant parameters, restraint system models, head/neck loadings, padding, and intrusion are discussed in the context of accident reconstruction.

The Hybrid III dummy is the anthropomorphic test device specified in the federal regulation for occupant protection in frontal impacts. Performance requirements for the Hybrid III neck are defined in Part 572E of the Code of Federal Regulations, based on biomechanical research and development by General Motors. Compliance requires meeting specified corridors for the input to the system and the response of the system. In 1991 and 1992, a collaborative test effort was undertaken by a Task Group of the Dummy Testing Equipment Subcommittee of the SAE Human Biomechanics and Simulation Standards Committee. Ten dummy calibration laboratories participated in this effort. The Hybrid III neck flexion test, as specified by Part 572E, was the focus of this investigation.

Automatic occupant sensing is acknowledged as an important addition to airbag and crash sensing systems. Increased system performance will result by being able to control deployment based on the presence, orientation and behavior of the passenger. This paper examines the theoretical background of using electric fields to obtain the desired information about vehicle occupants and the challenges of implementing with high reliability on a mass production and mass use basis.

While constantly striving to increase the levels of occupant protection, the need to intelligently detect occupancy has been identified. As different systems were considered, a optical based system was selected because of it's reliability and potential for reasonable cost feasibility. This paper describes the system detection philosophy, function, packaging and application. The paper also discusses the potential of the system for out of position sensing and its implications for smart airbag development.

For many years we have supplied both damped and undamped accelerometers to automotive companies for use in their road and crash tests. Here we present results which reconfirm the conformity of damped accelerometers to automotive crash testing.

The continuing increase in the performance of restraint systems has led to a drastic increase in the number of actuator devices. The individual wiring of the igniters becomes more and more problematic through the accompanied large number of plug connections and cables. Along with demands for weight and volume reduction, there are requirements for EMI and short circuit protection to eliminate erroneous deployment and misuse. As a solution, a new multi-protocol dual wire bus system is described that has the capability to supply energy and address multiple peripheral output stages to simultaneously fire any combination of actuators.

Topsy is a modular system designed for occasional measurements of all composite inertial, kinematic, and compliance parameters which appear in today's sophisticated mathematical simulation models. The emphasis in its design is not “production-line” testing, but research: the operator can observe the vehicle's reaction to developing forces; and as insights develop he can modify the test program as he goes along. Test errors are minimized by running all tests under servo control with continuous display of all data and recording of all known error sources, while the operators closely monitor the test and the developing data. The test facility is organized around an “infrastructure” consisting of baseplates, vehicle locating fixtures, scales, hydraulic and pneumatic power sources, interchangeable valve assemblies and actuators, and transducers. These are organized along with specialized devices into the several forms required for the different tests.

The measurement of angular rotation has many applications in crash testing, particularly in tracking the motion of crash dummies. There are currently a few devices for determining angular rotation. These include accelerometer arrays, magnetohydrodynamic (MHD) sensors, potentiometers, and high speed films. However, there are problems associated with all of these methods. Systron Donner has developed a new device called a “Quartz Rate Sensor” or “QRS”. The QRS utilizes a piezoelectric chip which produces a DC voltage proportional to the rate of rotation of the sensor about its sensitive axis. Angular displacement can then be determined from a simple integration. Results of preliminary tests performed at The U.S. Department of Transportation's Vehicle Research and Test Center suggest that the QRS's yield very accurate results.

The moment of inertia of the crankshaft cannot be ignored when analyzing the dynamics of a motorcycle. In this research, the tire friction force (calculated by drag and tire side force) was used as an index of the drive performance. The ratio of roll rate and steering torque (here after referred to as a roll rate gain) was used as an index of the cornering performance, and it was analyzed as the influence of the moment of inertia of a crankshaft on the drive performance as well as cornering performance. As a result, the influence on drive performance and cornering performance by the moment of inertia has been found.

Conventional restraint systems designed to meet US FMVSS standards only have one level of operation. The seat belt imparts a restraint force to the occupant reflective of belt stiffness characteristics and the airbag is either inflated or not inflated. The system is tuned to one crash scenario, typically a 30 mph (48 kph) barrier crash with an unbelted 50th%ile MHIII dummy. Situations involving other occupants, crash speeds or belt usage conditions may result in tradeoffs to maintain acceptable results for all conditions. Currently, there is considerable interest in adaptive restraint systems that can detect various crash conditions and adjust the restraint system to provide increased levels of protection. There is also a great deal of interest in systems that can detect an out of position occupant and adjust the airbag deployment to lessen the possibility of deployment induced injuries.

This paper describes the contribution of simulation to the development of the new Automotive Stability Management System (ASMS) of ITT. The benefits and limitations of simulation especially with respect to experimental testing with prototype vehicles are discussed. The paper will outline how cost and time to market have been reduced by Off-Line Simulation (OLS) and Real-Time Simulation (RTS). During the development of ASMS, new control algorithms were designed and first validated in the laboratory. Simulation has offered an insight into the vehicle dynamics that is difficult to obtain with prototype vehicles. It has been possible to study the interactions of the vehicle control system and vehicle dynamics under all circumstances. Some simulation examples of typical maneuvers are discussed.