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This paper describes the initial works related to the study of Internal Combustion Engines, as an object of mechanical design, at the Universidad Tecnológica de Pereira. It is reported a concise, complete methodology for simple model of internal combustion engine. The emphasis of the paper is placed on the use of the in-cylinder parameters (pressure and temperature) and inertial loads in the crank-slider mechanism to derive the loads that act on all the components of the crank-slider mechanism as well as the theoretical output torque for a given geometrical structure and inertial properties. These loads can then be used to estimate the preliminary dimensions of engine components in the initial stage of engine development. To obtain the pressure and temperature inside the cylinder, under different operation parameters, such as air fuel ratio and spark angle advance, a Zero dimensional model is applied. The heat transfer from the cylinder and friction are not taken into account.

In one of the fatigue tests for wet friction materials, “bump test”, an inertia-type rig equipped with a multi-disk assembly is used. One of the steel disks in the assembly has radial bumps for the purpose of creating high local contact pressure and high temperature. Due to the severe contact conditions, a comparative testing for different friction materials can be conducted within a relatively small number of cycles. In the paper, a design of a “bump” assembly used for automotive wet friction materials is described. Based on both experimental tests and advanced contact modeling, non-uniform contact pressure generated by the bumps and resulting temperature are estimated. The computational model is used then to study the influence of the modulus of elasticity of the friction material and reaction plate thickness on the contact conditions. The bump fatigue tests lead ultimately to material failure.

The extensive use of rotative machines in the diverse branches of the modern world has made the rising undesirable mechanical and acoustic vibration levels to be a problem of special importance for the machines normal operation as for the communities that are each time more affected by the problem. It makes the study of vibration and acoustic phenomena also to be even more important and the applications of its concepts more sophisticated. Several are the concepts used for decreasing vibration levels, like common dampers, hydraulic dampers, active dampers, natural frequencies changes and others. The choice of use of one or another depends greatly on the engineering possibilities (weight, energy, physical space, other components functional interference, vibration levels, etc.) as well as the cost of implementation of each one.

As a typical parameter of the road-vehicle interface, the road friction potential acts an important factor that governs the vehicle motion states under certain maneuvering input, which makes the prior knowledge of maximum road friction capacity crucial to the vehicle stability control systems. Since the direct measure of the road friction potential is expensive for vehicle active safety system, the evaluation of this variable by cost effective method is becoming a hot issue all these years. A ‘wheel slip based’ maximum road friction coefficient estimation method based on a modified Dugoff tire model for distributed drive electric vehicles is proposed in this paper. It aims to evaluate the road friction potential with vehicle and wheel dynamics analyzing by using standard sensors equipped on production vehicle, and fully take the advantage of distributed EV that the wheel drive torque and rolling speed can be obtained accurately.

This paper presents a new design method for solving the vehicle vibration problem induced by engine drive, by using a μ-synthesis. We have tried the active control of engine mounts to insulate the vibration of engine. We experimented on the effects by using computer simulation and vibration simulator. Computer simulation results show that resonance peak can be effectively reduced. We have also confirmed the effect of vibration simulator, which shall be reported in this paper.

SPARE TIRE elimination is a problem that has defied tire engineers for years. Because the space it occupies is wanted for other purposes, increased efforts are being applied to the search for a solution. This paper describes one approach — the dual compartment tire. This is made up of two tires, one inside the other, both of which are inflated at all tiines. If the outer tire is punctured, the inner tire supports the car until it reaches a service station. According to the author, tests indicate that this solution holds promise of eliminating the spare — if the cost can be lowered.*

Linked front and rear braking systems are difficult to implement properly on motorcycles due to the large changes in wheel loading under braking. At the braking limit, there is little to no load on the rear wheel and any brake torque could lock it, making the vehicle laterally unstable. Therefore, most motorcycles have independent controls for the front and rear brakes, requiring the rider to balance the brake force distribution. Electric motorcycles have the ability to utilize the drive motor to apply braking torque at the rear wheel. In this paper a control technique has been developed to link rear wheel braking torque to the front brake lever without risking rear tire lock. Thereby, it is also possible to recapture the energy from rear wheel braking. The control strategy has been tested on a transient pitch model, with rotating wheels and tire model data.

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Two methods for calculating speed from curved tire marks were investigated. The commonly used critical speed formula and a computer simulation program were evaluated based on their ability to reproduce the results of full-scale yaw tests. The effects of vehicle braking and friction coefficient were studied. Twenty-two yaw tests were conducted at speeds between 70 and 120 km/h. For half of the tests, about 30% braking was applied. Using the measured sliding coefficient of friction, both the critical speed formula and the computer simulations under-predicted the actual speed of the vehicle. Using the measured peak coefficient of friction, both methods over-estimated the actual speed. There was less variance in the computer simulation results. Braking tended to increase the speeds calculated by the critical speed formula.

It was anticipated that during X-29 extended duration, high angle-of-attack flight (40 to 70 deg), aircraft ECS performance would significantly degrade. Computer modelling of the system indicated that the performance of the ECS decreased as the angle of attack increased. Modifications to improve system performance were analyzed and, as a result of this analysis, ECS hardware modifications have been incorporated on the aircraft. The High-Alpha Flight Test Program has proven the validity of these modifications. To date, the ECS on Ship No. 2 has performed well within its nominal operating parameters in the high-alpha regime.

Abstract Autonomous vehicles (AVs) rely heavily upon their perception subsystems to “see” the environment in which they operate. Unfortunately, the effect of variable weather conditions presents a significant challenge to object detection algorithms, and thus, it is imperative to test the vehicle extensively in all conditions which it may experience. However, the development of robust AV subsystems requires repeatable, controlled testing—while real weather is unpredictable and cannot be scheduled. Real-world testing in adverse conditions is an expensive and time-consuming task, often requiring access to specialist facilities. Simulation is commonly relied upon as a substitute, with increasingly visually realistic representations of the real world being developed.

Demands of the earthmoving industry for indepth tire knowledge and performance capabilities has placed increased responsibility on the tire manufacturer for establishing operating limits. The challenge of meeting these demands has resulted in an increasing amount of controlled tire testing conducted under simulated field conditions. One of the areas of required information has been for the establishment of Dozer and Loader tire capabilities when operating in Load and Carry service. Since tire heat becomes a major potential problem in Load and Carry service, a method was required to determine the performance capabilities of Dozer and Loader tires so that optimum tire life could be achieved. This paper covers the need for tire limits; basic Dozer and Loader tire design requirements; the method established for determining tire capabilities in Load and Carry service, and finally the factors differentiating this rating system from the TMPH system which is used for transport type vehicles.

With COSMOsim, OTSL is looking to better virtually recreate diverse driving conditions to enable safe and accurate verifications at a point when autonomous driving continues to move toward practical use around the world.

In order to provide effective cooling for astronauts during extravehicular activities (EVAs), a liquid cooling and ventilation garment (LCVG) is used to remove heat by a series of tubes through which cooling water is circulated. To better predict the effectiveness of the LCVG and determine possible modifications to improve performance, computer simulations dealing with the interaction of the cooling garment with the human body have been run using the Wissler Human Thermal Model. Simulations have been conducted to predict the heat removal rate for various liquid cooled garment configurations. The current LCVG uses 48 cooling tubes woven into a fabric with cooling water flowing through the tubes. The purpose of the current project is to decrease the overall weight of the LCVG system. In order to achieve this weight reduction, advances in the garment heat removal rates need to be obtained.

A review of passenger tire construction and the engineering properties required of belt ply materials is presented. Comments are made on the areas of wire cord construction that must be investigated in order for the cost of wire cord to be reduced. Included are elastic modulus, dimensional stability, adhesion to rubber, environmental sensitivity, column strength, tensile strength, bending modulus, and endurance limit. The joint responsibilities of the equipment manufacturers, wire cord manufacturers, and tire companies are discussed.

A review of tire testing in the winter environment is presented from the viewpoint of an independent testing laboratory. The independent tester, by necessity, must satisfy the particular requirements of individual customers. A description of the drive traction truck which was designed to meet these individual client requirements is presented. Also, a comparison of results obtained by the various techniques of analysis is included.

The performance of winter tires is characterized by snow traction and ice skid tests. Winter tire testing is reviewed in regards to the hardware used, design of a test program, site selection, and data analysis. The description of the hardware includes a review of a new traction measurement system. The system incorporates a traction truck with an instrumented axle at a driven wheel position interfaced with a mini-computer which controls the test, stores the measurements, and performs the data analysis.

Winter testing of cars and tires for consumer comparisons is not an easy task to begin with; this is further complicated by the fact that reliable methods for evaluating performance and access to good testing conditions are unavailable to most magazines. The testing group at Tekniikan Maailma Magazine, Finland, has been fortunate to have both the right conditions as well as reasonable resources to develop methods of testing to the extent that they provide sufficiently reliable data to assess vehicle and tire performance in winter conditions. Before any final evaluations are published in the magazine, the weighing of different factors, i.e. the amount of importance placed on different performance characteristics, is carefully considered. In order to achieve a meaningful ranking of these products in relation to different characteristics, constant reference runs, statistical research methods, and highly skillful test drivers are employed.