Search Results

The requirement of “zero defects” is rapidly finding its way as a “standard” of quality in numerous quarters. This phrase has great psychological appeal, and is often taken literally at all levels in an organization even though quality motivation may be the intention. It is common to believe that when zero defects are found in the sample, this must be the case for “all the rest” as well. In this paper the technical side of “zero defects” is examined. We look at the statistics of zero defects and show what is implied about lot or process quality when zero defects is the actual sample outcome. The focus is on attribute measurements and includes some special cases where a significant measurement error exists and cases where a Bayesian statistical analysis may be appropriate.

Many accidents occur today when distant objects or roadway impediments are not quickly detected. To help avoid these accidents, longer-range safety systems are needed with real-time detection capability and without requiring a line-of-sight (LOS) view by the driver or sensor. Early detection at intersections is required for obstacle location around blind corners and dynamic awareness of approaching vehicles on intersecting roadways. Many of today's vehicular safety systems require short LOS distances to be effective. Such systems include forward collision warning, adaptive cruise control, and lane keeping assistance. To operate over longer LOS distances and in Non-LOS (NLOS) conditions, cooperative wireless communications systems are being considered. This paper describes field results for LOS and NLOS radio links for one candidate wireless system: 5.9GHz Dedicated Short Range Communications (DSRC).

Oil pumpability in passenger car gasoline engines was well-characterized by an ASTM program and by individual researchers in the 1970's and early 1980's. Oil pumpability in diesel engines however, was not investigated to any significant extent until the mid-1980's. This study was initiated to define the performance of several commercial viscosity modifiers in different formulations containing 3 detergent-inhibitor (DI) additive packages and 4 basestock types. The test oils were run at -18°C (0°F) in a Cummins NTC-400 diesel engine. The results, when statistically analyzed, indicated that a new, second generation olefin copolymer (OCP) viscosity modifier had better performance than a first generation OCP and, furthermore, had performance equal to a polymethacrylate (PMA) viscosity modifier. The analysis also showed that one DI/base stock combination had a significant effect on performance.

For the past four years the San Francisco Fire Department has owned and operated an American La France Triple Combination Engine Company powered with a Boeing Model 502 gas turbine engine. This engine company, in first line fire service, has illustrated the practicability of the gas turbine in vehicular applications. The purpose of this paper is to outline the experience gained by the use of a gas turbine engine in such an installation.

Many newer commercial vehicles have an event data recorder (EDR) that can record pre-event and post-event speeds. The EDR is incorporated into the engines electronic control module (ECM). In this study, the accuracy of the ECM-reported speed was tested during acceleration, gear shifting and braking at speeds between 16 and 88 km/h (10 to 55mph). The ECM-reported speed was compared to the speed measured by a calibrated optical 5th wheel. The results showed that the accuracy of the ECM-reported speed matched closely during acceleration, cycled to periods of under-reporting the speed during hard braking due to the ABS brake function, briefly under-reporting the speed after letting off the throttle for braking or gear shift and briefly over-reporting the speed near the end of a gear shift phase. This study also looked at calibration factors of the ECM and their effect on the ECM-reported speed.

In the modern and fast growing automotive sector, reliability & durability are two terms of utmost importance along with weight & cost optimization. Therefore it is important to explore new technology which has less weight, low manufacturing cost and better strength. The new technology developed always seek for a quick, cost effective and reliable methodology for its design validation so that any modification can be made by identifying the failures. This paper presents the rig level test methodology to validate and to correlate the CAE derived strain levels, life cycle & failure mode of newly developed light weight stabilizer link for EV Bus suspension

Understanding customer expectations is critical to satisfying customers. Holding customer clinics is one approach to set winning targets for the engineering functional measures to drive customer satisfaction. In these clinics, customers are asked to operate and interact with vehicle systems or subsystems such as doors, lift gates, shifters, and seat adjusters, and then rate their experience. From this customer evaluation data, engineers can create customer loss or preference functions. These functions let engineers set appropriate targets by balancing risks and benefits. Statistical methods such as cumulative customer loss function are regularly applied for such analyses. In this paper, a new approach based on the Taguchi method is proposed and developed. It is referred to as Taguchi Customer Loss Function (TCLF).

An unique bonding mechanism was studied after several instances, where the linings stuck to the brake drums on transit buses, were reported. Evidences suggested that the linings were “glued” to the brake drums surface after wear debris (dust) was turned into “adhesive paste” through complicated thermal and chemical changes. Factors such as the friction materials, environment and service conditions, which could activate and deactivate the lining bonding, were observed and discussed. The prevention measures are proposed.

Proper lubrication of moving parts is a critical factor in internal combustion engine performance and longevity. Determination of ideal lubricant change intervals is a prerequisite to ensuring maximum engine efficiency and useful life. When oil change intervals are pushed too far, increased engine wear and even engine damage can result. On the other hand, premature oil changes are inconvenient, add to vehicle maintenance cost, and result in wasted natural resources. In order to determine the appropriate oil change interval, we have developed an oil condition sensor that measures the electrical properties of engine oil, and correlates these electrical properties to the physical and chemical properties of oil. This paper provides a brief background discussion of the oil degradation process, followed by a description of the sensor operational principles and the correlation of the sensor output with physical and chemical engine oil properties.

As part of an overall effort to support the National Highway Traffic Safety Administration's (NHTSA) national program to increase seat belt usage, General Motors instituted an employe seat belt use incentive program at the General Motors Technical Center in Warren, Michigan. This program was responsible for raising seat belt use at the Tech Center from 36% to 70% during its 5 1/2 month duration. The program was patterned, in part, after research work done by professor E. Scott Geller of the Virginia Polytechnic Institute and State University under a grant from the General Motors Research Laboratories and a program conducted by Berg Electronics (a DuPont subsidiary). The intent of the program was to provide sufficient positive incentive to employes to buckle up for an extended period of time, thereby establishing a seat belt use habit that will continue after the incentives are no longer offered.

The onboard “SODART” telescope silicon detector cooling system of the “Spectrum-X-Gamma” observatory, which is designed for the space objects X-ray radiation study, is described. The scale-down model of the passive cooling system description and thermal vacuum test results of this model are given. In the real cooling system the minimal detector temperature at 300 mW heat release is expected about 107 K.

This paper presents, chemistry, test data and processing procedures on a non toxic and environmentally friendly chrome-free conversion coating alternative with the same level of adhesion and secondary corrosion resistance as that found in chrome containing conversion coating systems. Test data from military and independent sources will be presented on secondary coating adhesion, electrical conductivity, filiform and neutral salt-spray corrosion resistance as compared to chromate based systems .on magnesium, aluminum and zinc and their respective alloys. The European “RoSH” initiative will not allow for the presence of any hexavalent chromium on imported electrical components as of July first of 2006. Trivalent chromium based systems generate hexavalent chromium due to the oxidation of the trivalent chromium and as such will not be allowed.

In automotive electronics on-board diagnostics does the fault diagnosis and reporting. It provides the level of robustness required for the control electronics against various faults. The amount of diagnostic information available via on board diagnostics are depends on the type of vehicle. Pre-supply fuel pump is the component in the common rail hydraulic system. It pumps the fuel from the fuel tank to the inlet valve of the high pressure fuel pump. Electronic control unit synchronizes its operation with high pressure fuel pump. A dedicated driver module in the ECU controls the operation of pre-supply fuel pump. The driver module consist of an ASIC with internal voltage, current monitoring modules for the fault diagnosis and the pre-drivers to control external HS and LS power stages. The software part of the OBD programmed in the internal memory of the ASIC. The “Rds_on” of the power MOSFETs are used for the fault detection purpose.

This paper presents a fatigue criterion based on stress invariants for the frequency-based analysis of multiaxial random stresses. The criterion, named “Projection-by-Projection” (PbP) spectral method, is a frequency-based reformulation of its time-domain definition. In the time domain PbP method, a random stress path is first projected along the axes of a principal reference frame in the deviatoric space, thus defining a set of uniaxial random stress projections. In the frequency-domain approach, the damage of stress projections is estimated from the stress PSD matrix. Fatigue damage of the multiaxial stress is next calculated by summing up the fatigue damage of every stress projection. The criterion is calibrated on fatigue strength properties for axial and torsion loading. The calculated damage is shown to also depend on the relative ratio of hydrostatic to deviatoric stress components.

A large number of testing procedures have been developed to ensure vehicle safety in common and extreme driving situations. However, these conventional testing procedures are insufficient for testing autonomous vehicles. They have to handle unexpected scenarios with the same or less risk a human driver would take. Currently, safety related systems are not adequately tested, e.g. in collision avoidance scenarios with pedestrians. Examples are the change of pedestrian behaviour caused by interaction, environmental influences and personal aspects, which cannot be tested in real environments. It is proposed to use augmented reality techniques. This method can be seen as a new (Augmented) Pedestrian in the Loop testing procedure.

Vehicle dynamics is a discipline of mechanical engineering that benefited of significant improvements thanks to the progress of computational engineering. Vehicle dynamics engineers are using CAE for the development of a vehicle with MBS and FEA. The concurrent use of these two technologies is a standard in the automotive industry. However the current simulation process is not fully efficient because local geometrical and material nonlinearities are not accurately modeled in classical MBS software. This paper introduces a methodology for vehicle dynamics simulation integrating MBS capabilities in one single nonlinear FEA environment enabling an accurate modeling of nonlinearity in vehicles.