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Research has shown that there are many factors that affect the long-term performance of nitrogen oxides (NOx) control systems used in diesel engine applications. However, if the NOx emissions can be accurately monitored, it might be possible to restore performance by making adjustments to the control systems. This paper presents results from a study that tested the durability of 25 NOx sensors exposed to heavy-duty diesel exhaust for 6,000 hours. The study, conducted by the Advanced Petroleum-Based Fuels - Diesel Emission Controls (APBF-DEC) project, tested the sensors at various locations in the exhaust stream.

In order to reduce oil consumption resulting from leakage via valve guides, spring tensioned lip seals are applied. By the choice of oil side lip contact angle, degree of garter spring leverage, radial sealing force, and surface roughness of the valve stem, the metered oil leakage may be controlled and optimised. The application of an elastomer with greater wear resistance in a Fluoro-polymer basis (FKM) ensures correct functioning over the working life of vehicle engines.

Ceramic honeycomb structures have been used successfully as catalyst supports in gasoline-powered vehicles for the past ten years. They are currently the leading candidate for trapping and oxidizing the carbonaceous particulate emissions in diesel-powered vehicles. In both of these applications the long term durability of the ceramic substrate is of prime importance. This, in turn, depends on the physical properties of cellular structure, cyclic nature of service loads and design of the mounting assembly. This paper examines the nature and dependence of both the mechanical and thermal stresses in the substrate on its geometry, properties, mounting parameters, and the operating conditions. It also compares the observed failure modes with those predicted by the theory. The paper concludes with a set of recommendations for optimal systems design and acceptable operating conditions which will promote the long term durability of the ceramic substrate.

A multi-year technology validation program was completed in 2001 to evaluate ultra-low sulfur diesel fuels and passive diesel particle filters (DPF) in several different diesel fleets operating in Southern California. The fuels used throughout the validation program were diesel fuels with less than 15-ppm sulfur content. Trucks and buses were retrofitted with two types of passive DPFs. Two rounds of emissions testing were performed to determine if there was any degradation in the emissions reduction. The results demonstrated robust emissions performance for each of the DPF technologies over a one-year period. Detailed descriptions of the overall program and results have been described in previous SAE publications [2, 3, 4, 5]. In 2002, a third round of emission testing was performed by NREL on a small subset of vehicles in the Ralphs Grocery Truck fleet that demonstrated continued robust emissions performance after two years of operation and over 220,000 miles.

Intersection collisions currently account for approximately one-fifth of all crashes and one-sixth of all fatal crashes in the United States. One promising method of mitigating these crashes and fatalities is to develop and install Intersection Advanced Driver Assistance Systems (I-ADAS) on vehicles. When an intersection crash is imminent, the I-ADAS system can either warn the driver or apply automated braking. The potential safety benefit of I-ADAS has been previously examined based on real-world cases drawn from the National Motor Vehicle Crash Causation Survey (NMVCCS). However, these studies made the idealized assumption of full installation in all vehicles of a future fleet. The objective of this work was to predict the reduction in Straight Crossing Path (SCP) crashes due to I-ADAS systems in the United States over time. The proportion of new vehicles with I-ADAS was modeled using Highway Loss Data Institute (HLDI) fleet penetration predictions.

Mechanical property information is presented for the composite system, chopped glass fibers plus polypropylene matrix, where effective fiber-to-matrix adhesion has been achieved. The data presented were developed to serve three major purposes: to establish coupled glass reinforced polypropylene (coupled GRPP) as a material of a different class than conventional GRPP, to provide long-term data (creep and stress relaxation) for coupled GRPP which might form the basis for engineering design, and to illustrate the effects of such process-related factors as coupling, glass fiber concentration, fiber length, and fiber orientation on the structural properties of coupled GRPP systems.

It has been known for more than 50 years that some diesel engines could be fueled for short periods with vegetable oils, either neat or with hydrocarbon fuel additives. World overproduction of soybean oil is increasing its potential as an economical diesel fuel extender. The subject test program was undertaken to determine long-term effects of this alternate fuel on a modern, high-speed diesel engine. The choice of a vegetable oil (soybean oil) as an alternative diesel engine fuel or fuel extender rather than the other major biomass motor fuel (ethanol) is related to the relative properties of these fuels. The common U.S. vegetable oils are much closer to hydrocarbon (No. 2D) diesel fuel than is ethanol in both cetane rating and volumetric energy content. Unlike ethanol, the vegetable oils can be blended 1:1 with No. 2D fuel to produce engine power and volumetric fuel consumption levels practically identical to those obtained with 100% No. 2D fuel.

A nominal 520 kW (thermal) air-conditioning system based on the seasonal storage of cold water in an aquifer has cooled a University of Alabama building since 1983. During cold weather, ambient, 18° C water is pumped from warm supply wells, chilled to about 6° C in a cooling tower, and reinjected into separate cold storage wells. In warm weather, water is withdrawn from the cold wells and pumped through building heat exchangers for air conditioning. Presented here are results of 6 years of study [sponsored by the U.S. Department of Energy through Pacific Northwest Laboratory] of the first successful U.S. application of this technology. This system yields high energy efficiency, with measured annual average COP of about 5 (SEER = 17 Btu/Wh), and energy recovery efficiency ranging from 40 to 85%, shifts utility loads from summer to winter, and no chlorofluorocarbon (CFC) release.

After about a decade of considerable investments in polymer electrolyte fuel cell (PEMFC) and in solid oxide fuel cell (SOFC) technology, both are being actively considered for vehicle applications. The two vehicle applications being most actively considered for fuel cells are propulsion (mainly for PEMFC) and auxiliary power (for both PEMFC and SOFC). For all transportation applications, fuel cells promise the benefits of clean and quiet operation, potentially low maintenance and high efficiency, and ultimately greater utility to drivers and passengers. Initial system and vehicle prototypes have started to demonstrate some of these benefits, but much technology development is still needed before commercialization can occur. Not surprisingly then, there are serious hurdles to be overcome if fuel cells are to become true competitors for internal combustion engines (ICEs) in automotive applications.

Storage stability of different diesel fuels containing cat-cracked stocks was examined using various aging conditions. The degradation of fuel during storage was monitored through insoluble formation but also through reaction of nitrogen compounds known to be involved in the fuel degradation process. The influence of aging in injector fouling tendency was also investigated on an IDI engine on test bench. Various stabilizer additives (tertiary amines, dispersant…) were tested. Best results were obtained with dispersants which prevent sediment agglomeration making them able to cross the filter mesh. Additives limit indole evolution without inhibiting completely sediment formation, proving that other reactions take place. We showed that fuel oxidability is not modified by additives. None of the tested formulations is effective on fuel darkening. After aging, surfactants remain effective on injector fouling. Another way of improving the storage stability of Diesel fuel is hydrotreatment.

Longer warranties, improved performance and higher operating efficiency demanded by end-users are placing more rigorous service requirements on all engine components. Seals are particularly vulnerable due to their organic nature. This paper reviews a series of fluoroelastomers to determine their long-term serviceability when in contact with conventional high-temperature engine lubricants and coolants. A typical application might be seals used for engine cylinder sleeves.

The objective of this study was to assess the long-term capability and impact of a rapid, in-situ impedance measurement technique known as Harmonic Compensated Synchronous Detection. This technique consists of a sum-of-sines excitation signal that includes a targeted selection of frequencies and only requires one period of the lowest frequency. For a given frequency range of 0.1 Hz to approximately 2 kHz, the measurement duration would only be ten seconds. The battery response is captured and synchronously detected for impedance spectra measurements. This technique was compared to laboratory-based performance degradation measurements using commercially available lithium-ion cells. The cells were aged for 150,000 cycles at accelerated rates using temperatures of 40 and 50°C. Every 30,000 cycles, cycle-life testing was interrupted to gauge degradation at the reference temperature of 30°C.

Four GL-5 gear lubricants, one containing a dispersed solid borate additive, two sulfur-phosphorus (S-P), and a S-P synthetic, were evaluated in the axles and transmissions of 26 new Class 8 trucks in a 250,000-mile field test. Significantly lower axle break-in wear (factory to first oil change) was found for the borate lubricant versus a S-P factory-fill oil. The four test oils showed statistically significant differences in axle wear as shown by iron wear plots and analysis of end-of-test parts: the borate and synthetic oils were equal while the other two oils gave higher wear. All oils gave acceptable seal performance. The borate lubricant showed the best thermal stability as judged by parts cleanliness.

An effective development strategy is needed to implement short development times for mechatronic systems, which themselves are becoming increasingly more complex. Besides the ever-increasing use of advanced computer-based development tools, special attention must be paid to the validation of the functional behavior of the prototype during all phases of the development process. Using the example of systems for powertrain automation, this paper depicts the resulting advantages arising from the long-time observation of time-based values of open- and closed-loop controlled systems. The method of long-time observation introduced here is based on the acquisition and analysis of information in all phases of the development process. Where numerous vehicles are already in the hands of selected customers during fleet tests, these late phases in particular are covered thoroughly. It should be noted that newly developed systems are normally unobserved or only subjectively evaluated by the driver.

Different realizations of adaptive cruise control systems (ACC) have been tested. Firstly, only throttle access has been realized. In addition to this, the second realization utilizes access to the automatic transmission ECU. Finally, the third realization includes access to the brakes. Essentially, the first two versions are characterized by different states (e.g. acceleration, hold speed, deceleration), while the third version is based on continuous longitudinal vehicle control, e.g. using fuzzy methods [1]. Practical results showed high system stability for all three ACC versions. Advantages and disadvantages of each realization have been worked out based on simulated and measured results. Measurements showed that the first two solutions are sufficient to handle many traffic situations. However, in comparison with these versions, the third realization turned out to be the most powerful one.

Cutting out of the lane in the process of following a car is a natural driving scene that often happens, and it is also a typical scene faced by self-driving cars. In this scenario, the driver may either change lanes after the car in front or continue in the original lane. Based on the natural driving data, the longitudinal driver response behavior of the scene cut out of the car in front is analyzed. For the driver's longitudinal response behavior, firstly, the acceleration behavior domain related to TV1 (Target Vehicle I) was divided by support vector machine method, and then the acceleration time was represented by the transverse body overlap rate of the Vehicle and the Vehicle in front at the initial acceleration time, and the acceleration response process was represented by the average acceleration and the maximum acceleration. The influencing factors were analyzed by single factor analysis of variance and Pearson correlation test.

The purpose of this paper is to present specifications for rubber tired vehicles operating on a cooperative highway. These specifications will allow control systems to be designed which could meet the requirement of a new generation of automobiles and trucks operating on roadways which can carry more vehicles/hr. These vehicles are to be electronically guided and controlled. The problem is divided into two aspects: 1. lateral control and 2. longitudinal control. Lateral control will be done by a sensor system that can “see” the road ahead and steer the vehicle toward the road and will be presented in another paper. Longitudinal control will be the subject of this paper. It involves keeping a series of dissimilar vehicles properly spaced while operating at high speeds. Safe spacing must be kept as vehicles enter and exit the vehicle stream, and as disturbances occur such as hills and winds.

Earlier research1 suggests there may be positive offset in the longitudinal G sensor in Toyota Corolla Gen 02 EDR’s. This research tests if a similar offset is present in Toyota Gen 04 EDR’s in the 2007 Yaris. A series of low speed forward and rearward collisions into a stationary vehicle were conducted. In addition to the installed vehicle ACM, additional identical “ride along” ACM’s were installed back to back, one front facing and one rear facing. The vehicle was also instrumented with a video VBOX to record speed at impact, and with the high precision “IST” accelerometer reference instrumentation. ACM’s facing toward the crash under-reported the negative longitudinal Delta V. After the initial impact was over, these forward facing ACM’s had a positive slope and at the end of the 200 ms recording were reporting a positive net Delta V, indicating a G sensor bias. The ACM’s facing away from the crash over reported the positive longitudinal Delta V.

Although it is intuitively and qualitatively known that a treaded tire has a larger drawbar pull than a smooth tire, little is known quantitatively about all the interfacial forces and the origins of these forces of a treaded tire traversing a snow cover. There have been relatively few studies regarding the quantitative effects of tread pattern on tire-snow interaction due to the complexity of the tread pattern, the enormous amount of computational resources needed for high-fidelity numerical simulations, and the difficulty of measuring all the interfacial forces between a tire that is much harder than snow. The purpose of this paper is to understand the effects of a simplified tread pattern of a two-dimensional rigid tire on the interfacial forces between a tire and low-density snow. The parameters to vary included the wheel load, as well as a full-range of longitudinal slip.

Driven by the necessity to reduce costs and improve products quality the automotive industry replaced the design method known as "trial and error" by those grounded on mathematical and physical theory. In this context, a longitudinal performance test was made by BAJA SAE UFMG team, in order to acquire vehicular performance data that will be used to validate computer models. The methodology consists of sensors and data acquisition system research, validation, fixation and installation in the vehicle, test and process of acquired data. From these steps, correlated data were acquired from magnitudes such as angular velocity in transmission shafts, global longitudinal acceleration and velocity, travel of break and throttle pedals and pressure inside of master cylinder. These results developed the knowledge about vehicular dynamic allowing the improvement of futures prototypes.