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Efficiency of Driveshafts have not been analyzed in great detail in the past due to their relatively high efficiency. However, it is possible to obtain about a 0.1 percent increase in fuel economy by decreasing driveshaft torque losses by about 20 percent, owing to the combination mode fuel calculation. In order to improve fuel economy it is necessary to increase the efficiency of the constant velocity universal joint (C.V.J.) used for driveshafts. Additionally, propeller shafts with improved heat characteristics are required. It is for these reasons that this project is conducted. In this paper, the motion of two typical joint used for front-engine, front-drive passenger cars is analyzed geometrically and efficiency formulas are derived. One of the joints is a Rzeppa joint, used on the wheel side of the driveshaft and the other is a tripot joint, used on the differential side. These formulas are then verified by experiment.

This paper describes an experimental and epidemiological investigation of the potential application of a specific rollover occupant protection system, consisting of a rollover protective structure and occupant restraint (collectively referred to hereafter as ROPS), to all-terrain vehicles (ATVs). The ROPS investigated in this paper was proposed by Dahle [1987] as a means to improve the safety of ATV operation. Crash tests were performed with an unhelmeted instrumented dummy on 4-wheel ATVs equipped with the prototype Dahle ROPS (hereafter referred to as D-ROPS); the test results established that the D-ROPS design exhibited the potential for serious injury or death in lateral rollover, rearward pitchover, collision, and oblique frontal impact accident scenarios. Review of ATV-associated 1986 fatality reports from the U.S.

Volvo has developed the first production emission control system to fully utilize a three-way catalyst. Called the “Volvo Lambda-sond system”, it is applied to the 4-cylinder in-line B21 engine, and employs three essential new components - an exhaust gas composition sensor, an additional feed-back loop to the continuous fuel injection system, and the catalyst. Outstanding certification results were achieved, especially for NOx, combined with good driveability, power output, and fuel economy. The development and performance of the system, and the test procedures used, are described in detail, and its future potential and limitations are discussed.

The development of a modern transportation product requires that the safety of the product be considered at every stage of its life, from initial design to ultimate product disposal. Virtually all of the decisions that can positively effect product safety are made during the product design stage with most of the critical decisions being made early in the process. As a result, early incorporation of system safety into the design process has been shown repeatedly to result in safer products. Incorporation of formal system safety programs into ground transportation vehicle design programs is comparatively recent. Historically, in both the automotive and the heavy goods vehicle industry, product safety has been provided through consistent over design of evolutionary system elements to ensure correct functioning under repeated exposure to worst case stresses.

The deionized water/ethylene glycol coolant used in the Ford Focus Fuel Cell Vehicle (FCV) requires very low conductivity (< 5 μS/cm) to avoid current leakage and short circuiting, presenting a unique water chemistry issue. The coolant's initially low conductivity increases as: 1) ions are released from system materials through leaching, degradation and/or corrosion, and 2) organic acids are produced by ethylene glycol degradation. Estimating the leaching potential of these ions is necessary for design and operation of fuel cell vehicles. An on-board mixed-bed, ion exchange resin filter is used to maintain low conductivity by removing leached or produced ions. Various candidate materials were evaluated for leaching potential by exposing them to coolant at the design operating temperature for several months and periodically analyzing the coolant for ions.

The increasing trend of automotive electronics mandates the introduction of multiple processors in automotive electronics. The automotive electronic systems have to operate in harsh environments having a high temperature range, high humidity, unpredictable vibrations and rapid voltage variation. In such environment, the automotive electronic systems become vulnerable to intermittent and transient failures. Depending upon the importance of the tasks performed by the processor, a processor’s failure inside automotive electronic system may lead to serious consequences. Fault tolerant computing techniques are used to keep the computer systems running in spite of one or more processors’ failures. The concept of fault tolerant is well known in many applications such as airplanes, industry, and military. However, the question of fault tolerant design has drawn little attention in automotive electronics.

While the CAN Calibration Protocol or CCP is a reasonably well known standard in Europe that continues to gain acceptance, its exposure in the American automotive electronics arena has to some extent been limited to the engine calibration area. A closer examination of the protocol reveals that the CCP is not just for calibration. With many general-purpose features including flash programming capability, the CAN Calibration Protocol is useful for a wide range of module development activities. CCP users have access to online measurement data and the ability to calibrate modules. This allows software development to occur not only in a lab environment but also during an in-vehicle test. Even though U. S. companies using or evaluating the CAN Calibration Protocol include DaimlerChrysler, Ford, GM, Delphi, Motorola, TRW, Visteon, and several others, many product development engineers are unaware of this potentially reusable software.

In an ever-transforming sector such as that of private road transport, major changes in the propulsion systems entail a change in the perception of the noise sources and the annoyance they cause. As compared to the scenario encountered in vehicles equipped with an internal combustion engine (ICE), in electrically propelled vehicles the heating, ventilation, and air conditioning (HVAC) system represents a more prominent source of noise affecting a car’s passenger cabin. By virtue of the quick turnaround, steady state Reynolds-averaged Navier Stokes (RANS)- based noise source models are a handy tool to predict the acoustic power generated by passenger car HVAC blowers. The study shows that the most eminent noise source type is the dipole source associated with fluctuating pressures on solid surfaces.

In 2023, the European Union set more ambitious targets for reducing greenhouse gas emissions from passenger cars: the new fleet-wide average targets became 93.6 g/km for 2025, 49.5 g/km in 2030, going to 0 in 2035. One year away from the 2025 target, this study evaluates what contribution to CO2 reduction was achieved from new conventional vehicles and how to interpret forecasts for future efficiency gains. The European Commission’s vehicle efficiency cost-curves suggest that optimal technology adoption can guarantee up to 50% CO2 reduction by 2025 for conventional vehicles. Official registration data between 2013 and 2022, however, reveal only an average 14% increase in fuel efficiency in standard combustion vehicles, although reaching almost 23% for standard hybrids. The smallest gap between certified emissions and best-case scenarios is of 14 g/km, suggesting that some manufacturers’ declared values are approaching the optimum.

Aeroacoustics is important in the automotive industry, as it significantly influences driving comfort. Particularly in the case of battery electric vehicles (BEVs), the flow noise is already crucial at lower driving speeds, since these generate barely any drive noise and the masking effects produced by the engine are eliminated. Due to the increasing importance of drag minimization and elimination of the exhaust system, the underbody of BEVs is typically very streamlined and exhibits a low acoustic interference potential. However, even small geometric modifications to the vehicle can lead to changes in the flow around the vehicle and consequently to significant noise sources. Thus, significant flow resonances in the low frequency range below 30 Hz have been detected on certain vehicle configurations. Initial investigations have shown that the flow around the front wheel spoilers is relevant for the development of the flow phenomenon.

Sustainability is both an ethical responsibility and business concern for the aerospace industry. Military and commercial avionics developers have pushed toward a common standard for interfaces, computing platforms, and software in hopes of having “reusability” and reducing weight with backplane computing architectures which, in theory, would support commonality across aircraft systems. The integrated modular avionics (IMA) and military Future Airborne Capability Environment (FACE) standards are two such examples. They emerged to support common computing architectures for reuse and sustainability concepts, from the beginning of aircraft development to the sundown or mortality phase. Pitfalls of Designing, Developing, and Maintaining Modular Avionics Systems in the Name of Sustainability looks at technological, organizational, and cultural challenges making reuse and IMA platform models difficult to fully realize their sustainability goals.

Testing techniques for creating rollovers have been a subject of much study and discussion, although previous work has concentrated on creating a repeatable laboratory test for evaluating and comparing vehicle designs. The two testing methodologies presented here address creating rollover tests that closely mimic a specific accident scenario, and are useful in accident reconstruction and evaluation of vehicle performance in specific situations. In order to be able to recreate accidents on off-road terrain, a test fixture called the Roller Coaster Dolly (RCD) was developed. With the RCD a vehicle can be released at speed onto flat or sloping terrain with any desired initial roll, pitch and yaw angle. This can be used to create rollover collisions from the trip stage on, including scenarios such as furrow trip on an inclined road edge.

Windshields, with their low internal damping, are an acoustical weak link in automotive glazing. In the past, acoustically-enhanced glass products were typically achieved by utilizing solid and mass product design elements to increase the glass thickness. This is no longer acceptable as automakers are interested in weight savings, especially as they develop vehicles that are more fuel-efficient. Laminated safety glass, with a standard polyvinyl butyral (PVB) interlayer, is used extensively for automotive windshields and side glazing, and offers improved acoustical performance over tempered glass. However, the standard PVB interlayer is not designed specifically for acoustical and Noise, Vibration and Harshness (NVH) purposes. Studies of the parameters affecting acoustical properties and actual noise reduction capability of standard laminated glass led to the development of an acoustical grade PVB interlayer.

There are exposures of the body to accelerations in the lumbar and thoracic regions on a regular basis with everyday activities and exercises. The purpose of this study was to evaluate the response of the thoracic and lumbar regions in human volunteers subjected to vigorous activities. A total of 181 tests include twenty volunteers subjected to four test scenarios: “plopping” down in a seat, a vertical jump, a vertical drop while in a supine position, and a vertical drop while seated upright in a swing. Each of the latter three activities included three severity levels with drop heights ranging from 25 mm to 900 mm. Volunteers selected represent the anthropometry of the general population including males and females at a wide range of weights (54 to 99 kg), heights (150 to 191 cm), and ages (26 to 58 years old). Instrumentation for each volunteer included tri-axial accelerometers attached to custom-fit mounts that were secured around the lumbar and upper thoracic regions.

It has been observed that locked-wheel skidding friction values are essentially vehicle- and tire-independent. It has been tacitly assumed by most crash reconstructionists that any ABS-equipped vehicle would also decelerate at nearly the same rate as any other ABS-equipped vehicle. This paper will review literature with relevant straight-line test results on paved roadways and gravel, and present additional results from recent tests generated with four modern vehicles built by three manufacturers. Results from the recent testing showed that locked-wheel skidding values on a concrete roadway were similar for all four vehicles, but the ABS-improvement on the same roadway varied. On gravel, ABS was always less effective than locked-wheel skidding. ABS and locked-wheel results on gravel had less car-to-car variation than tests conducted on concrete.

Two models of a tractor-semitrailer combination are created based on vehicles used in a field operational test. One model is used for tilt table simulations and the other is supplied driving inputs from the field operational test at two dangerous road curves (“hotspots”). Dynamic rollover conditions are simulated for several hotspot trips and varying payload conditions by extrapolating the trip speed profiles. The dynamic rollover threshold from the vehicle simulations is shown to be, on average, about 25% lower than the static stability factor over the range of loading conditions. The difference between the critical speeds at rollover for the range of loading conditions is approximately 3 m/s.

15-5PH is a precipitation-hardening, martensitic stainless steel used for primary structural elements such as engine mounts where corrosion resistance, high strength, good fatigue and fracture toughness is required. The material composition is defined in AMS5659M. This alloy can be either Type 1 - vacuum arc remelt (VAR) or Type 2 - electro slag remelt (ESR) and is most commonly heat treated per SAE AMS-H-6875 or AMS2759/3 to condition H1025 (an ultimate tensile strength of 155 ksi [1070 MPa] minimum). Typically material handbooks have limited fatigue data and most data is only for Type 1. Therefore, the fatigue properties of 15-5PH H1025 stainless steel for both Type 1 and Type 2 were determined. The objective of the fatigue testing was to generate a family of S-N curves (maximum stress versus number of cycles to failure) for a series of stress ratios across the entire range of cycles to failure.

Aerospace Recommended Practice (ARP) 4754 Revision A (ARP4754A), “Guidelines for Development of Civil Aircraft and Systems,” [1] is recognized through Advisory Circular (AC) 20-174 (AC 20-174) [2] as a way (but not the only way) to provide development assurance for aircraft and systems to minimize the possibility of development errors. ARP4754A and its companion, Aerospace Information Report (AIR) 6110, “Contiguous Aircraft/System Development Process Example,” [3] primarily describe development processes for an all new, complex and highly integrated aircraft without strong consideration for reused systems or simple systems. While ARP4754A section 5 mentions reuse, similarity, and complexity, and section 6 is intended to cover modification programs, the descriptions in these sections can be unclear and inconsistent. The majority of aircraft projects are not completely new Products nor are they entirely comprised of complex and highly integrated systems.

Improving the energy balance of vehicles is an effective way of lowering CO2 emissions. Among other things, this does entail mounting demands on the power wiring system. The intention is, for instance, to adapt the drive train to facilitate such functions as more efficient recuperation, e-boost and sailing with the aid of a 48V starter generator and a 48V battery. In addition, it is a matter of electrifying mechanical components with the aim of energy-efficient demand management to save fuel. The 48V power wiring system as an addition to the 12V system is a promising option where the task is to make the low-voltage wiring system of vehicles in the mass-market segment more powerful. Raising system voltage to 48V has the effect of fundamentally improving the efficiency of electricity generation and power distribution in the vehicle because of the reduced current and therefore the diminished ohmic losses.