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This paper proposes an approach to use ABS wheel speed sensor signals together with other vehicle state information from a brake control module to detect an unbalanced tire or tires in real-time. The proposed approach consists of two-stage algorithms that mix a qualitative method using band-pass filtering with a quantitative parameter identification using conditional least squares. This two-stage approach can improve the robustness of tire imbalance or imbalances. The proposed approach is verified through vehicle testing and the test results show the effectiveness of the approach.

Variable amplitude torsion, bending, and combined torsion and bending fatigue tests were performed on an axle shaft. The moment inputs used were taken from the respective history channels of a cable log skidder vehicle axle. Testing results indicated that combined variable amplitude loading lives were shorter than the lives of specimens subjected to bending or torsion alone. Calculations using strain rosette readings indicated that principle strains were most active around specific angles but also occurred with lesser magnitudes through a wider angular range. Over the course of a biaxial test, cyclic creep narrowly limited the angles and magnitudes of the principal strains. This limitation was not observed in the calculated principal stress behavior. Simple life predictions made on the measured strain gage histories were non-conservative in most cases.

When considering ride comfort and precision there are lots of components in the vehicle suspensions that have influence in this behavior and some ride occurrences (mainly higher frequencies) are rubber bushing responsibility but due their compliance, other vehicle attributes, steering and handling, can be affected. So the correct components tuning can maintain or improve vehicle attributes to address desired brand DNA and vehicle its specific needs. These studies were done considering the elastokinematics of front axle only due need of improve its comfort concerning higher frequencies (impacts and harshness). In addiction, correlation between subjective evaluation and objective data acquisition/post processing is desirable to optimize development time. Based in subjective directional, the activities time was reduced and final configuration reached faster.

The objective of this project was to develop a methodology for the diagnosis of vibrations of the vehicle's steering wheel. This paper will describe an attempt at developing a systematic approach for describing the vibrations felt, what the sources might be, and how various steering system parameters might affect the vibrations.

Computer simulation technology coupled with indoor laboratory facilities is being used in the automotive industry to provide up-front assessment of vehicle performance. This paper presents a technique to evaluate passenger vehicle tire wear performance as related to suspension and tire design early in the design process. Motivation for developing this tool is to optimize suspension and tire design to tire wear early in the design process. This approach has resulted in reductions in vehicle development time, dependency on outdoor testing and the need for expensive prototype vehicles. A full vehicle ADAMS model of a production vehicle is used to animate vehicle suspension kinematic motions, and dynamic tire forces of vehicle maneuvers for a preselected outdoor tire wear route. Time histories of five vehicle parameters are generated: radial force, slip angle or lateral force, camber, velocity and driving and braking torques.

A hybrid approach to predict road-induced loads in vehicle structures is presented. The technique involves full vehicle dynamic simulation using measured wheel forces, absolute wheel vertical displacements, and steering angle as input. The wheel vertical displacement is derived from the measured wheel acceleration. This approach avoids the use of tire-road interface modeling. It also improves the conventional loads measuring process with minimum instrumentation and data acquisition. Existing load data from a test vehicle is used to validate this approach. Computed component loads show good agreement with measurements.

In order to effectively evaluate automatic transmission gear noise and vibration performance using a hemi-anechoic test facility, it is essential to understand the coupling mechanism between the transmission internals and the dynamometers and associated shafting. Once this coupling mechanism is well understood, each major frequency response of the resulting torsional vibration operating data can be properly categorized according to the source: transmission-internal, facility, or driveshaft. This knowledge helps noise and vibration engineers properly manage vibration peaks in transmission operating data by ensuring that the issue of concern is not inadvertently influenced by the facility system. Analytical simulations and tests were performed on a transmission operated in a hemi-anechoic facility to evaluate gear vibration using various driveshafts, followed by a program of vehicle testing.

A laboratory axle efficiency test using a torque sweep method has been developed. Vehicle test limitations, previous axle efficiency tests and origin of current test are discussed. Test development, equipment and importance of technique are presented. Correlation with vehicle tests is shown and usefulness of data for evaluating lubricant and axle design changes is discussed. An evaluation of test results shows that the torque sweep method has the capability of identifying changes that may not show with vehicle tests.

This paper discusses current powertrain matching methodology and its applications. Modular computer programs, which model each component of the vehicle/powertrain system, simulate the vehicle over specified driving cycles to project fuel economy and performance. Fuel economy opportunities due to better powertrain matching are discussed, including optimum engine sizing, torque converter matching, transmission gear ratio spacing and shift scheduling, axle ratio and vehicle weight effect. An emission projection technique utilizing time weighted engine speed/load points generated either by experiment or by analytical models is used to quantify fuel economy/emissions trade-offs.

IN 1957 Ford introduced in its passenger cars a new rear axle incorporating a straddle-mounted pinion. This paper describes the development and features of the 2¼-in. offset axle. The author thinks the most interesting feature of the development problem was the design of the hypoid gears. The 1957 gears were designed with the deepest possible teeth to give maximum fatigue strength. They maintained the conventional scheme of 50 deg on the pinion and about 15 deg on the gear.

The history, system philosophy, design evolution, and performance of the Sure-Track anti-lock automotive braking system are presented and discussed. Considerations of performance, driver skill, reliability, and commercial acceptance resulted in the choice of a vacuum-electronic rear wheel anti-lock system that incorporates individual wheel speed sensing and control of braking as a pair. The system provides superior directional stability under “panic” braking conditions while maintaining stopping distance equal to or shorter than those for locked wheels under most road conditions.

A systematic vehicle design and development procedure to minimize axle noise has been developed. This method reduces engineering lead time and optimizes the vehicle design through the utilization of computer analysis, laboratory testing, and road testing.

This paper presents three test methods used to evaluate rear axle lubricants: the Ford motored rear axle test, the high speed Timken test, and the rear axle score test. In each instance, results are described, including the development of new rear axle test methods. Lubricants successfully completing these tests are considered for further evaluation.

A rear obstacle detector and warning unit was designed to detect the presence of an object in the rear blind spot behind a vehicle and warn the operator if the possibility of backing over the object exists. A semiconductor infrared laser and a semiconductor detector, mounted on a vehicle behind the rear axle with a unique optical lens system proved capable of detecting small objects up to 10 ft directly behind the vehicle. The unit performance verified the ability to design an obstacle detection system with a sharply defined field of view using infrared technology.

The demand for improved fuel economy in both cars and trucks has emphasized the need for lighter weight components. The application of high strength steel to wheels, both rim and disc, represents a significant opportunity for the automotive industry. This paper discusses the Ranger HSLA wheel program that achieved a 9.7 lbs. per vehicle weight savings relative to a plain carbon steel wheel of the same design. It describes the Ranger wheel specifications, the material selection, the metallurgical considerations of applying HSLA to wheels, and HSLA arc and flash butt welding. The Ranger wheel design and the development of the manufacturing process is discussed, including design modifications to accommodate the lighter gage. The results demonstrate that wheels can be successfully manufactured from low sulfur 60XK HSLA steel in a conventional high volume process (stamped disc and rolled rim) to meet all wheel performance requirements and achieve a significant weight reduction.

To serve the need of in-line rear axle diagnostics as well as other types of transmission inspection, an angular sensor development has been undertaken. It has resulted in a new device, incorporated into a system which performs angular error sensing at three levels. High precision of better than 0.003% in velocity variations is achieved. A continuous check of the null-error status of the devices is maintained in order to ensure maximum reliability of the readings. An easy on-site calibration check is available which eliminates the need for any precision calibrating fixture. The device is configured to accommodate a pass-through drive shaft for in-line mounting. A rugged design and immunity to rotor imperfections are advantageous in a plant environment.

Axle dynamometer tests were carried out to evaluate the effects of rear axle lubricant viscosity-temperature behavior and frictional characteristics on vehicle fuel economy. Using a Ford 9 inch 2.75:1.0 ratio axle, a set of input speed and load conditions was selected to permit simulation of the CVS and EPA highway driving cycles. Lubricant temperature was varied from -30°C to 100°C to simulate seasonal climatic effects. Data obtained for three lubricants differing in viscosity-temperature behavior were interpreted assuming a lubrication model including both elastohydrodynamic and mixed lubrication conditions. From these data, fuel economy projections were made using a vehicle simulation computer program. The results predict that improvements in vehicle fuel economy on the order of a few percent can be made at low temperatures by use of low viscosity synthetic lubricants, but only small effects are projected for the CVS and EPA highway cycles.

This report concerns the development of a small radio-telemetry torquemeter package intended to replace a current slip ring driveshaft torque meter system. Included in this report is a package description, a comparative test report and application recommendations. The torquemeter package developed can be used in any driveshaft, vehicle or otherwise, in place of a standard universal joint. Package constituents are a strain gaged universal joint cross and telemetry consisting of a modern FM transmitter and FM receiver. Transmitter power is available in battery form, or an inductive power supply can be built into the transmitter and receiver. The package was installed in series with a slip ring unit to conduct a comparative test utilizing both power supplies. Test results were not influenced by power supply and indicate identical data.

This paper describes Programmed Ride Control (PRC), the automatic adjustable shock absorber system designed and patented by Ford Motor Company. The system utilizes low shock absorber damping under normal driving conditions to provide soft boulevard ride, automatically switching to firm damping when required for improved handling. The system's microprocessor control module “learns” where the straight ahead steering wheel position is, allowing the system to respond to absolute steering wheel angle. A closed loop control strategy is used to improve system reliability and to notify the driver in the event of a system malfunction. Fast acting rotary solenoids control the damping rate of the shock absorbers.

Drivelines used in modern pickup trucks commonly employ universal joints. This type of joint is responsible for second driveshaft order vibrations in the vehicle. Large displacements of the joint connecting the driveline and the rear axle have a detrimental effect on vehicle NVH. As leaf springs are critical energy absorbing elements that connect to the powertrain, they are used to restrain large axle windup angles. One of the most common types of leaf springs in use today is the multi-stage parabolic leaf spring. A simple SAE 3-link approximation is adequate for preliminary studies but it has been found to be inadequate to study axle windup. A vast body of literature exists on modeling leaf springs using nonlinear FEA and multibody simulations. However, these methods require significant amount of component level detail and measured data. As such, these techniques are not applicable for quick sensitivity studies at design conception stage.