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As part of the International Lubricant Standardization and Approval Committee's (ILSAC) goal of developing a global automatic transmission fluid (ATF) specification, members have been evaluating test methods that are currently used by various automotive manufacturers for qualifying ATF for use in their respective transmissions. This report deals with comparing test methods used for determining torque capacity in friction systems (shifting clutches). Three test methods were compared, the Plate Friction Test from the General Motors DEXRON®-III Specification, the Friction Durability Test from the Ford MERCON® Specification, and the Japanese Automotive Manufacturers Association Friction Test - JASO Method 348-95. Eight different fluids were evaluated. Friction parameters used in the comparison were breakaway friction, dynamic friction torque at midpoint and the end of engagement, and the ratio of end torque to midpoint torque.

The National Highway Traffic Safety Administration (NHTSA) and the Insurance Institute for Highway Safety (IIHS) have both developed crash test methodologies to address frontal collisions in which the vehicle's primary front structure is either partially engaged or not engaged at all. IIHS addresses Small Overlap crashes, cases in which the vehicle's primary front energy absorbing structure is not engaged, using a rigid static barrier with an overlap of 25% of the vehicle's width at an impact angle of 0°. The Institute's Moderate Overlap partially engages the vehicle's primary front energy absorbing structure using a deformable static barrier with 40% overlap at a 0° impact angle. The NHTSA has developed two research test methods which use a common moving deformable barrier impacting the vehicle with 20% overlap at a 7° impact angle and 35% overlap at a 15° impact angle respectively.

Rollover crashes have continued to be a source of extensive research into determining both vehicle performance, and occupant restraint capabilities. Prior research has utilized various test procedures, including the FMVSS 208 dolly fixture, as a basis for evaluating vehicle and restraint performance. This research, using 2001 Nissan Pathfinder sport utility vehicles (SUVs), was conducted to update the status of passenger vehicle rollover testing, and evaluate dynamic test repeatability with a new test procedure. A series of eight rollover tests was conducted using these SUV vehicles, mounted on a modified FMVSS 208 rollover dolly fixture, with instrumented dummies in both front seat positions. This test protocol involved launching the vehicles horizontally, after snubbing the dolly fixture, and having the leading-side tires contact curbing for a trip mechanism.

With the increasing emphasis on Systems Engineering, there is a need to ensure that Electrical/Electronic (E/E) Systems Endurance Testing of vehicles, in a real world environment, prior to Production Launch, is performed in a manner and at a technological level that is commensurate with the high level of electronics and computers in contemporary vehicles. Additionally, validating the design and performance of individual standalone electronic systems and modules “on the bench” does not guarantee that all the permutations and combinations of real-world hardware, software, and driving conditions are taken into account. Traditional Proving Ground (PG) vehicle testing focuses mainly on powertrain durability testing, with only a simple checklist being used by the PG drivers as a reminder to cycle some of the electrical components such as the power window switches, turn signals, etc.

The protection of the environment has become a worldwide concern. To reduce the effects of engine coolant on the environment, ways to minimize the amount of coolant released into the environment were investigated. One option is to develop a super long-life coolant. The key issue in developing a long-life engine coolant is selecting an appropriate inhibitor. The inhibitor should be stable over time and completely anticorrosive. In general carboxylic acids are considered to be the class of inhibitors with the highest stability. However, various lab studies have shown the long-term use of monocarboxylic acid could form the foreign substance that causes blockage in radiators. Therefore, the mechanism leading to the formation of foreign substance was determined. A series of carboxylic acids and additives were evaluated. An optimum formulation was then determined, resulting in the development of the Super Long Life Coolant.

This paper describes a study of drag reduction devices for production pick-up trucks with a body-on-frame structure using full-scale wind tunnel testing and Computational Fluid Dynamics (CFD) simulations. First, the flow structure around a pick-up truck was investigated and studied, focusing in particular on the flow structure between the cabin and tailgate. It was found that the flow structure around the tailgate was closely related to aerodynamic drag. A low drag flow structure was found by flow analysis, and the separation angle at the roof end was identified as being important to achieve the flow structure. While proceeding with the development of a new production model, a technical issue of the flow structure involving sensitivity to the vehicle velocity was identified in connection with optimization of the roof end shape. (1)A tailgate spoiler was examined for solving this issue.

A study was made on a control method for an adaptive cruise control (ACC) system that uses vehicle-to-vehicle communication to achieve a substantial improvement in string stability and natural headway distance response characteristics at lower levels of longitudinal G. A control system using model predictive control was constructed to achieve this desired ACC vehicle behavior. Control simulations were performed using experimental data obtained in vehicle-following driving tests conducted on a proving ground course using a platoon of three manually driven vehicles. The results showed that the proposed ACC system satisfactorily achieved higher levels of required ACC performance.

Wheels play an important role in determining the aerodynamic drag of passenger vehicles. This is because the contribution of wheels to aerodynamic drag comes from not only the wheels themselves, but also from the interference effect between wheel wakes and the base wake. As far as the authors are aware, there have been no reports about aerodynamic drag sensitivity to wheel shape factors for different vehicle types and different exterior body shapes. The purpose of this study was to clarify CD sensitivity to wheel shape factors for a sedan and an SUV, including different rear fender shapes. Many different wheel configurations were investigated in terms of the CD, base pressure and flow fields in wind tunnel tests. Multiple regression analyses were conducted to clarify CD sensitivity to each wheel shape factor based on the test data. This study revealed high CD sensitivity factors for both the sedan and SUV.

An electric vehicle (EV) has less powertrain energy loss than an internal combustion engine vehicle (ICE), so its aerodynamic accounts have a larger portion of drag contribution of the total energy loss. This means that EV aerodynamic performance has a larger impact on the all-electric range (AER). Therefore, the target set for the aerodynamics development for a new EV hatchback was to improving AER for the customer’s benefit. To achieve lower aerodynamic drag than the previous model’s good aerodynamic performance, an ideal airflow wake structure was initially defined for the new EV hatchback that has a flat underbody with no exhaust system. Several important parameters were specified and proper numerical values for the ideal airflow were defined for them. As a result, the new EV hatchback achieves a 4% reduction in drag coefficient (CD) from the previous model.

A two-channel LDV system is used to obtain accurate airflow measurements around scale models of passenger cars in wind tunnel tests at the Nissan Research Center. A 2-watt argon-ion laser is employed as the light source. The main optical unit and probe head are connected by optical fibers. The probe head consists of a compact LDV probe with a beam expander and focusing lens with a long focal length can be easily traversed. A new type of signal processor, performing a digital autocorrelation function, is employed to process the Doppler signals. Mean airflow velocities and turbulence intensities are calculated by a micro computer to evaluate the flow fields. The results of preliminary experiments conducted with this system indicate that the system is not only capable of measuring the mean velocity components, including reverse flow, it can also provide accurate estimation of turbulence components.

Eight rollover research tests were conducted using the 2001 Nissan Pathfinder with a modified FMVSS 208 dolly rollover test method where the driver and right front dummy restraint performance was analyzed. The rollover tests were initiated with the vehicle horizontal, not at a roll angle. After the vehicle translated laterally for a short distance, a trip mechanism was introduced to overturn the vehicle. Retractor, buckle, and latch plate performance in addition to the overall seat belt performance was analyzed and evaluated in the rollover test series. Retractor pretensioners were activated near the rollover trip in three of the tests to provide research data on its effects. Various dummy sizes were utilized. The test series experienced incomplete data collection and a portion of the analog data was not obtained. National Automotive Sampling System (NASS) data was also analyzed to quantify the characteristics of real world rollovers and demonstrated the benefits of restraint use.

The thermal fatigue resistance of engine exhaust system parts has conventionally been evaluated in thermal fatigue tests conducted with a restrained specimen. However, the test results have not always been consistent with data obtained in engine endurance tests. Two new evaluation methods have been developed to overcome this problem. One is a method of predicting thermal fatigue life on the basis of nonlinear elastic and plastic thermal analyses performed with a finite element model and the ABAQUS program. The other is a method of evaluating exhaust system parts using an exhaust system simulator. This paper describes the concepts underlying the two methods and their relative advantages.

In recent years, the slip lock-up mechanism has been adopted widely, because of its fuel efficiency and its ability to improve NVH. This necessitates that the automatic transmission fluid (ATF) used in automatic transmissions with slip lock-up clutches requires anti-shudder performance characteristics. The test methods used to evaluate the anti-shudder performance of an ATF can be classified roughly into two types. One is specified to measure whether a μ-V slope of the ATF is positive or negative, the other is the evaluation of the shudder occurrence in the practical vehicle. The former are μ-V property tests from MERCON® V, ATF+4®, and JASO M349-98, the latter is the vehicle test from DEXRON®-III. Additionally, in the evaluation of the μ-V property, there are two tests using the modified SAE No.2 friction machine and the modified low velocity friction apparatus (LVFA).

Ride quality is an important purchasing consideration for consumers. It is typically defined in terms of noise, vibration and harshness. These phenomena are a result of vibrations caused at the engine/powertrain and from the road surface, which are transmitted to the passenger cabin. To minimize such vibrations, rubber parts are used extensively at mounting points for the cabin, such as engine mountings and suspension bushings. The vehicle development process increasingly requires performance testing, including rubber parts using CAE, prior to prototype evaluation. This in turn requires a rubber material model that can accurately describe dynamic characteristics of rubber components, particularly frequency and amplitude dependency.

An active vision system equipped with a high-speed pulsed light-emitting projector and a high-speed image sensor is proposed and applied to lane marker detection in this paper. The proposed system has the capability to suppress image information obtained from the background light and provides only the image information from the signal light emitted by the projector. This is accomplished by synchronizing image capture with the time of signal light emission. To reduce the power consumption and cost of the system, a relatively low intensity projector is used as the light source. The background illuminance on a bright day can be much higher than that of the signal. To improve the signal-to-background ratio, the signal light is modulated using a pulse width modulation technique. Then, the image is captured using a high-speed camera operating in synchronization with the time the signal light is emitted.

It is considered that door mirror drag is composed of not only profile drag but also interference drag that is generated by the mixing of airflow streamlines between door mirrors and vehicle body. However, the generation mechanism of interference drag remained unexplained, so elucidating mechanism for countermeasures reducing drag have been needed. In this study, the prediction formulas for door mirror drag expressed by functions in relation to velocities around the vehicle body were derived and verified by wind tunnel test. The predicted values calculated by formulas were compared with the measured values and an excellent agreement was found. In summary, new prediction formulas made it possible to examine low drag mirror including profile and interference drag.

This paper summarizes the major activities of CFD study on rear window buffeting of production vehicles during the past two years at DaimlerChrysler. The focus of the paper is the attempt to find suitable solutions for buffeting suppression using a developed procedure of CFD simulation with commercial software plus FFT acoustic post-processing. The analysis procedure has been validated using three representative production vehicles and good correlation with wind tunnel tests has been attained which has gained the confidence in solving the buffeting problem. Several attempts have been proposed and tried to find solution for buffeting reduction. Some of them are promising, but feasibility and manufacturability still need discussion. In order to find suitable solution for buffeting reduction, more basic research is necessary, more ideas should be collected, and more joint efforts of CFD and testing are imperative.

The purpose of this research is to develop an automatic shift control method that emulates an experienced driver's manual shift maneuver which enhances driving performance during sporty driving. Driver control maneuvers and vehicle behavior were observed throughout the process of braking, cornering, and accelerating out of a corner on a winding test track. Close correlations were found between driving maneuvers, longitudinal and lateral acceleration, and the selected engine speed. Based on the analysis, an index is proposed for estimating the intention of the driver to drive in a sporty manner. This index consists of the magnitude of acceleration in a friction circle and the maximum longitudinal acceleration restricted by the performance of the power train. An automatic transmission control based on the estimated driving intention was then developed to achieve the necessary and sufficient available force.

This paper summarizes a study on axle balance measurement and balancing strategies. Seven types of axles were investigated. Test samples were randomly selected from products. Two significant development questions were set out to be answered: 1) What is the minimum rotational speed possible in order to yield measured imbalance readings which correlated to in-vehicle imbalance-related vibration. What is the relationship between the measured imbalance and rotational speed. To this end, the imbalance level of each axle was measured using a test rig with different speeds from 800 to 4000 rpm with 200 rpm increments. 2) Is it feasible to balance axle sub-assemblies only and still result in a full-assembly that satisfies the assembled axle specification? To this end, the sub-assemblies were balanced on a balance machine to a specified level. Then with these balanced sub-assemblies, the full assemblies were completed and audited on the same balance test rig in the same way.

Knowledge of the loads experienced by a leaf spring suspension is required for the optimal design of the suspension components and frame. The most common method of representing leaf springs is the SAE 3 link model, which does not give good results in the lateral direction. In this paper, a beam element leaf spring model is developed. This model is validated using data obtained from laboratory tests done on leaf spring assemblies. The model is then subjected to actual road load data measured on the Proving Ground. Lastly, results from the beam element model are presented and compared with results obtained from proving ground tests. Overall, the beam element model gives good results in all directions except in situations where it is subjected to high fore/aft acceleration and high reverse braking events.