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Rolling vibrations of hypoid gears resulting from nonconjugacy of the teeth are explained, measured, and simulated using an electromechanical exciter system. Laboratory experiments have shown that there is a relationship between angular displacement error, acoustical gear noise, and structure-borne vibration. A new hypoid gear testing machine has been developed for making a rapid quality measurement based on the excitation of the tooth mesh frequency and its harmonics.

As IC engines decrease in displacement, their cylinder surface area to swept volume ratio increases. Examining power output of IC engines with respect to cylinder surface area to swept volume ratio shows that there is a change in power scaling trends at approximately 1.5 cm−1. At this size, it is suggested that heat transfer from the cylinder becomes the dominant thermal loss mechanism and performance and efficiency characteristics suffer. Furthermore, small IC engines (>1 cm−1) have limited technical performance data compared to IC engines in larger size classes. Therefore, it is critical to establish accurate performance figures for a family of geometrically similar engines in the size class of approximately 1.5 cm−1 in order to better understand the thermal losses that contribute to lower efficiencies in small IC engines. The engines considered in this scaling study were manufactured by 3W Modellmotoren, GmbH.

In the last five years, advances in laser technology and decreases in the cost of laser sensors and high precision motion systems have made it feasible to develop a laser-based product for measuring the geometry of screw threads. The operating principles of such a system will be described. A significant issue in the development of the system was the interpretation of thread dimensional standards which were written with contact gaging in mind. A second issue has been establishing correlations with other thread gaging methods, given the absence of master and grandmaster threaded artifacts.

More than 600 passenger cars were measured during winter and spring at the end of 2012 beginning 2013 in Antwerp Belgium in order to determine the effect of mileage and year of first registration on smoke emissions or smoke opacity from diesel light duty vehicles. All measurements were contacted in two different campuses of the University of Antwerp and under different ambient conditions. Various parameters such as ambient temperature, ambient humidity, car age, number of passengers in each cars, time of measurement etc. were taken into account and presented in this paper. All findings from these set of measurements were split into two big categories, those cars with less than 150,000km on the clock and the second one with those cars with higher number of mileage. The effect of ambient temperature but also the mileage on smoke opacity will be presented and discussed in more details.

The lack of measured data is a problem that often occurs when modeling physical human properties. This problem also occurs when trying to describe the human thigh with a finite element model. In this pilot study, an experimental chair was used to gather the required information. Each cushion of the chair consists of 81 pistons. Each piston is controlled individually by a computer. This experimental chair was used in two experiments. In the first experiment, the chair was used to measure the force length characteristics of deformed human thighs during unsupported sitting. In the second experiment, the measurement of the characteristics of undeformed thighs deformed by one piston was attempted. In this paper the test stand, the test procedures, the results und further experiments will be discussed.

We are basically interested in Sound Intensity whenever we deal with sources of sound in noise control. The development of techniques and new tools for the direct measurement of the flow of acoustic energy offer new ways for determination of source location, source ranking, energy flow path and absorption measurements. Optimum microphone probe configurations for different applications, digital processing and data presentation will be discussed. The use of true real time data processing in collection of energy flow data in mechanical structures is suggested as a new tool for the mechanical design engineer.

A system for measuring the friction surface temperature in disc clutches was developed. This system measures the transient surface temperature on rotating clutch discs by infrared detection. The temperature distribution on the friction surface can be obtained. The computer in the system records the temperature signals and processes them into color contour maps representing temperature distributions. Experiments were made in which the friction surface temperatures on a wet friction clutch disc were measured at various engagement speeds and forces. The experimental results showed that under the conditions used the friction surface temperature was so non-homogeneous that the temperature difference could be as much as 200°C at a moment in engagements. It was also found that the high temperature was concentrated on a narrow belt of friction surface in engagements. Tests were made only on the sintered-bronze-lined friction discs.

There are several different possibilities to analyze a squealing brake system. The present paper introduces a complex measuring system which is mounted on a complete vehicle axle at a test rig. This system was developed because the previously performed state-of-the-art tests did not allow any insights in the squeal triggering mechanisms. First of all, a frequency analysis was performed. Thereby the main vibrating parts and the directions of the oscillation could be determined during a squeal event. The second was a modal analysis of the vehicle axle, which was necessary to get further insights into the system as well as to verify an existing Finite Element Method model. Through these tests, however, it was not possible to get any insight into the contact area, and therefore it was impossible to determine the squeal triggering mechanism. Because of this limitation, special guide pins were developed, which are able to measure the vibrating friction force.

A system to measure transient temperature distribution on the brake disc rotor at high speed braking has been developed and its measuring principle and configuration were discussed in this paper. This system consists of two revolution sensors and two sets of optical fiber array, photoelectric elements, and microprocessor, which fiber array is so arranged that it faces the brake disc rotor. This new system has the following features: (1) Measuring is made using a visible radiation wavelength range for red hot temperatures higher than 550°C.

An X-ray diffraction analysis involving integrated intensities was applied to a series of 99.85% Cu, 0.15% Cd alloys which had been cold-rolled and annealed. It is shown that the reduction in integrated intensity, due to extinction, can be correlated with tensile strength. In addition, it is shown that the annealing behavior of this alloy can be characterized by a “tempering parameter” containing both time and temperature.

In order to simulate diesel exhaust of known composition, weighed amounts of various high-boiling hydrocarbons were evaporated into a stream of heated air. These mixtures were sampled continuously and the hydrocarbon contents measured with a heated flame ionization detector (FID). The evaporator unit and FID were operated at various temperatures and 375 F was optimum as regards percentage of input material accounted for (85–100%, for paraffins through C16), fast response, and repeatability. The FID was then used at various temperatures to measure total hydrocarbons in exhaust from a 1-cyl diesel engine. Again, 375 F was optimum for obtaining maximum apparent hydrocarbon concentration, fast response, and repeatability. Finally, FID measurements were obtained at 375 F on exhaust from the engine at various operating conditions, to assess the effects of operating variables on hydrocarbons.

Methods are presented for calculating the orthotropic elastic constants of a single sheet of rubber-coated tire fabric, using the elastic properties of the materials that go to make up the sheet and the geometry of construction of such a sheet. The expressions presented here are useful in estimating these quantities, although the problem is such that empirical methods must be used if the resulting expressions are to be kept simple enough so that the influences of specific variables can be clearly seen.

Tire uniformity measurements may be interpreted with some reservations to provide information regarding automobile ride disturbances at frequencies less than 60 cps (tire shake and roughness) and one type of handling disturbance (tire pull). A list of precautions and recommendations based on present or potential tire specifications is given in the first part of this paper, along with some machine and tire variables influencing numerical force variation values. In the second part, the waveforms of four uniformity measurements, radial force-variation, lateral force-variation, loaded radial runout, and free radial runout, are compared with the sites of splices in tires and substantial agreement is shown. Are-port on the capabilities and limitation of present day radial and lateral force-variance measuring as shown by the statistical analysis of a series of repeat measurements on two typical lots of passenger tires is given in the third part.

High speed schlieren video and pressure trace analyses were used to study the effects of turbulence on burning velocity in a fixed volume combustion chamber. Lean methane-air mixtures of equivalence ratios of 0.76 and 0.96 were ignited at 1 atm and 23°C. Schlieren images of flame growth were recorded on video at 2000 frames per second while combustion chamber pressure was simultaneously recorded. The turbulence intensity at ignition was set at 0 m/s to 4 m/s intensity with integral scale around 7.6 mm by pulling a perforated plate across the chamber prior to ignition. In the analysis, the turbulence parameters were adjusted for the effect of decay and rapid distortion in a closed vessel during combustion. Results of both video and pressure trace analyses show a linear relationship between turbulent burning velocity and turbulence intensity as expected. Moderate changes in equivalence ratio had a negligible effect on this relationship.

Emission controls, both exhaust and evaporative, have made it much more difficult to achieve satisfactory driveability. Since driveability is becoming a more critical factor, objective rating techniques are desirable. A surgemeter has been developed for objectively measuring vehicle surge, one driveability factor. A comparison of surgemeter ratings with surge ratings of expert drivers indicate that the surgemeter objectively measures surge. In one investigation, the surgemeter indicated that vehicle surge increased as the amount of exhaust gas recirculation required for NOx control increased. In another investigation, the surgemeter was used to compare surge in seven different vehicles as part of a more comprehensive vehicle driveability rating program. Good, overall vehicle driveability implies that the driver is satisfied with the automobile's power train operation.

Highly integrated gyro based systems are now available for vehicle testing. Up to 12 individual sensors are replaced by such systems. The installation is done in a few minutes and requires no external sensors attached to the vehicle. Results are provided in Earth fixed coordinates. This enables direct comparison of key test parameters, especially true heading, vehicle pitch and roll angle, vehicle speed, vehicle location and acceleration in all three directions. A single test is enough to qualify a vehicle. Basics are explained and some real world test results are discussed.

Most methods of vibration analysis focus on measuring the level of vibration. Some methods like ISO-2631 weigh vibration level based on human sensitivity of location, direction, and frequency. Sound can be similarly measured by sound pressure level in dB. It may also be weighted to human frequency sensitivity such as dBA but sound and noise analysis has progressed to measure sound quality. The characteristic and the nature of the sound is studied; for example equal or near equal sound levels can provide different experiences to the listener. Such is the question for vibration; can vibration quality be assessed just as sound quality is assessed? Early on in our studies, vibration sensory experts found a difference in 4 seats yet no objective measurement of vibration level could reliably confirm the sensory experience. Still these particular experiences correlated to certain verbal descriptors including smoothness/roughness.

Two experiments have been conducted to assess a method of measuring the whole-body vertical vibration experienced by persons seated on soft seats. The method utilises a transducer mount located between the seat and the body. Comfort contours obtained on hard flat seats are shown to be applicable to measurements made within a firm bar or plate placed on a cushion beneath the ischial tuberosities of a seated subject. However, since some mounts alter seat transmissibility a firm plate (SIT-BAR) contoured to cause seat compression similar to that produced by the buttocks is recommended for some applications.

When an airbag inflates rapidly during a car accident, the driver is exposed to a large impulsive wave of sound pressure of short duration that could possibly damage human hearing. The time signals of these impulsive waves are being measured using transducers of various types and sizes in order to investigate the repeatability of the measured results both for each given transducer and between transducers. The aim is to find a suitable way for manufacturers to test airbags and to be able to make meaningful data comparisons.

This paper presents a new way of measuring yaw rate of the vehicle using two accelerometers. Measurement of yaw rate is inevitable for vehicle stability control systems for contemporary high performance sedans and automatic steering control systems for intelligent vehicles. Compared with accelerometers, the cost of rate gyros used to measure the yaw rate is significantly higher. As an economical software solution to replace the high-cost rate gyros with minimal additional hardware, an algorithm to obtain yaw rate using two accelerometers is proposed in this paper.