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The present paper describes the system design for the Clear Vision auto defog system and the improvements made to the Integrated Dew Point and Glass Temperature (IDGT) sensor. The Clear Vision auto defog system has been implemented on a 2000 Cadillac DeVille. Preliminary validation tests demonstrate satisfactory performance.

A steering wheel is an indispensable component in an automobile. Although the steering wheel was invented about one hundred years ago and its structure has since become more and more complex with numerous innovations, documented analysis on steering wheel performance is very limited. Today, a steering wheel is not only a wheel that controls where your car goes; it also plays an important role in a vehicle occupant protection system. Therefore, many requirements have to be met before a steering wheel goes into production. With the development of computational mechanics and increasing computer capability, it has become much easier to evaluate the steering wheel performance in a totally different way. Instead of running prototype tests, steering wheel designs can be modeled virtually in various scenarios using finite element analysis, thus facilitating the development cycle.

Currently in the automotive industry, most software source code is manually generated (i.e., hand written). This manually generated code is written to satisfy requirements that are generally specified or captured in an algorithm document. However, this process can be very error prone since errors can be introduced during the manual translation of the algorithm document to code. A better method would be to automatically generate code directly from the algorithm document. Therefore, the automotive industry is striving to model new and existing algorithms in an executable-modeling paradigm where code can be automatically generated. The advent of executable models together with automatic code generation should allow the translation of model to code to be error free, and this error-free status can be confirmed through testing. A three-stage process is presented to functionally verify the model, functionally verify the automatically-generated code, and structurally verify the code.

A new optimal control strategy for dealing with braking actuator failures in a vehicle equipped with a brake-by-wire and steer-by- wire system is described. The main objective of the control algorithm during the failure mode is to redistribute the control tasks to the functioning actuators, so that the vehicle performance remains as close as possible to the desired performance in spite of a failure. The desired motion of the vehicle in the yaw plane is determined using driver steering and braking inputs along with vehicle speed. For the purpose of synthesizing the control algorithm, a non-linear vehicle model is developed, which describes the vehicle dynamics in the yaw plane in both linear and non-linear ranges of handling. A control allocation algorithm determines the control inputs that minimize the difference between the desired and actual vehicle motions, while satisfying all actuator constraints.

Biodiesel has become a major alternative fuel for automotive applications demonstrated by its increasing presence in the market place. This paper summarizes test results for recently collected retail samples of biodiesel (B100) and blended biodiesel from the U.S. and the European Union to provide a snap shot of current fuel quality in each market. Properties reported included biodiesel content, oxidation stability, acid number, water, metals, and glycerin content. For B100, only total contamination measured as particulates was significantly lower for the EU than the U.S. For blends containing up to 5% biodiesel, there were significant differences between the U.S. and the EU in sulfur content, oxidation stability (Rancimat), cetane number, and cloud point. For blends higher than B5, present only in the U.S., pump labeling was found to be a poor indicator of biodiesel content.

The General Motors Allison Two-Mode compound split parallel hybrid EP system for transit buses has been in production for over three years, accumulating over 20 million fleet miles. During this period of operation, extensive fuel economy analysis has been performed over multiple use cycles in multiple locations. This paper describes the in-use fuel economy results, as well as the hybrid system mode operations, the component utilization, and the controls improvements to maximize the hybrid fuel economy. Actual in-use data will be presented from individual vehicles, as well as the fleet averages encompassing a broad range of duty cycles. A chassis dynamometer testing results are discussed as an alternative evaluation method.

As an essential dimension of product harmony and craftsmanship, product sound quality has drawn increasing attention from customers in recent years. To meet this customer requirement, Delphi Corporation has been taking a proactive role in understating customer preferences, improving designs, and developing a sound quality knowledge base for this purpose. This study investigates the characteristics of the glovebox closure sound that affects the customer's perception of the product harmony and craftsmanship. Previous research has indicated that the perceived closure sound quality is affected by the spectral balance, the occurrence of multiple impulses, and the duration of the closing event. The primary goal of this study is to explore how these parameters affect the perception of glovebox sounds and to what extent. A jury evaluation was conducted with a sequence of glovebox closure sounds, which were derived from an existing recording.

Some Electronic Throttle Control (ETC) Air Control Valves (ACV) on automotive internal combustion engines are susceptible to icing of the throttle valve. Ice formation can result in an increase in torque required to open or close the valve. Laboratory studies were conducted to improve the understanding of throttle valve icing on electronic throttle control valves with both aluminum and composite (plastic) bodies over various bore sizes (4 cylinder to 8 cylinder engines). Study results indicated that ice compression at the bore and valve gap, not ice adhesion, is the major contributor to the ETC-ACV icing phenomenon. In addition, testing of parts with various bore sizes, orientations and surface cleanliness resulted in further understanding of the icing issue.

The rheological behavior of automatic transmission fluids (ATF) ranges from moderately shear-thinning to Newtonian. However, no commercially available ATFs are known to display shear-thickening behavior. A theoretical investigation was performed to determine if any advantages could be derived from the use of shear-thickening ATF in automatic transmission components and subsystems. A series of theoretical shear-thickening, shear-thinning, and Newtonian fluids were modeled by a power law function and compared to a reference shear-thinning ATF in simplified representations of transmission components and subsystem geometries. The results indicate that a shear-thickening ATF with zero shear viscosity, infinite shear viscosity, and power of 417 mPa-s, 6.23 mPa-s, and 1.03(dimensionless), respectively, displays optimized behavior with respect to the reference shear-thinning ATF.

Electro-mechanical brakes (EMBs) are emerging as a new approach to enhance brake system features as well as braking performance. This paper takes a fresh look at the switched reluctance (SR) drive as a possible prime mover technology for EMB applications. The switched reluctance motor has attractive potential, in view of its robustness, dynamic bandwidth and fault tolerance. An overall assessment of the approach is made based on bench performance of a prototype EMB caliper with an SR drive executing typical braking patterns. It is shown that the SR motor can provide the required overall brake actuator performance. Various implementation options are examined to lower cost, with particular focus on electronic design, control algorithms and motor position sensing.

Using standard industry tests, the oxidation stability of General Motors current factory-fill automatic transmission fluid (ATF) was compared to that of a proposed factory-fill ATF to be introduced for the 1995 Model Year. Full-scale transmission tests and Aluminum Beaker Oxidation Tests run at various temperatures showed that a proposed factory-fill fluid is substantially more resistant to oxidation than the current factory-fill ATF. Using Total Acid Number increase (Δ-TAN) as the measure of oxidation, a minimum of 35% improvement was obtained with a proposed factory fill. This improvement at least doubles the time to “perceived fluid failure” (Δ-TAN = 2.5).

This study examines the effectiveness of gaseous oxygen at preventing embrittlement in steel associated with exposure to gaseous hydrogen under static loading conditions. Notched C-ring samples machined from 4340 steel and heat treated to HRC 51-53 were used to test the neutrality of an oxygen-hydrogen gas mixture similar to that which may be used as a generant in an air bag inflator. The 29 percent oxygen to hydrogen gas ratio of the gas mixture was found to be sufficient to protect the steel from hydrogen embrittlement under static loading conditions. This would indicate that any steel with a hardness of HRC 51 or lower would be safe to use in gas-based air bag inflators containing a oxygen to hydrogen gas ratio of 29 percent or higher.

A RTD (resistive temperature device) high temperature sensor was developed for exhaust gas temperature measurement. Extensive modeling and optimization was used to supplement testing in development. The sensor was developed to be capable of withstanding harsh environments (-40° to 1000°C), typical of engine applications, including poisons, while maintaining high accuracy (< 0.5% drift after 500 hrs of aging at 950°C). The following sensor characteristics are presented: resistance-temperature curve, accuracy, response time, and long-term durability. In addition, a system error analysis program was developed with representative results.

With the inception of model-based design and automatic code generation, many organizations are developing controls and diagnostics algorithms in model-based development tools to meet customer and regulatory requirements. Advances in model-based design have made it easier to generate C code from models and help software engineers streamline their workflow. Typically, after the software has been developed, the models are handed over to a calibration team responsible for calibrating the features to meet specified customer and regulatory requirements. However, once the models are handed over to the calibration team, the calibration engineers are unaware of how to calibrate the features because documentation is not available. Typically, model documentation trails behind the software process because it is created manually, most of this time is spent on formatting. As a result, lack of model documentation or up-to date documentation causes a lot of pain for OEM’s and Tier 1 suppliers.

Because of the wide array of commercial or market fuels in use today, all components, engines, and vehicles must be vigorously tested to confirm emissions performance, driveability and material compatibility. To support the requirements of the modern global vehicle engineer, various testing and validation fuels are used to represent quality that ranges from good to poor for fuel that are currently in the market or that will be introduced into the market in the future. Testing and validation fuels have been developed specifically for emissions compliance testing to meet new environmental regulations in different parts of the world, vehicle performance and reliability needs. Demand for new testing and validation fuels will continue to grow.

With the wider use of Direct Injection Spark Ignition (DISI) vehicles in the marketplace, a program was conducted to develop a short-duration fuel injector fouling test. Once a specific driving cycle and base fuel combination was found to produce a significant increase in Long Term Fuel Trim (LTFT), several Deposit Control Additive (DCA) technologies were evaluated for their ability to keep the direct gasoline injectors clean. The increase in LTFT is indicative of fuel injector fouling and a corresponding decrease in flow through them. The test vehicles for this program were a 2008 General Motors Pontiac Solstice GXP equipped with a DISI 2.0 liter turbocharged I-4 and a 2008 Audi A4 equipped with a DISI 3.2 liter V-6 engine. A proprietary base fuel formulated to mimic a U.S. EPA 65th percentile fuel was tested to assess its deposit forming tendencies.

A requirement of many modern safety-critical automotive applications is to provide failsafe operation. Several analysis methods are available to help confirm that automotive safety-critical systems are designed properly and operate as intended to prevent potential hazards from occurring in the event of system failures. One element of safety-critical system design is to help verify that the software and microcontroller are operating correctly. The task of incorporating failsafe capability within an embedded microcontroller design may be achieved via hardware or software techniques. This paper surveys software failsafe techniques that are available for application within a microcontroller design suitable for use with safety-critical automotive systems. Safety analysis techniques are discussed in terms of how to identify adequate failsafe coverage.

In 2002, NHTSA statistics indicate air bag deployments saved an estimated 1,500 lives; however, reports of occupants having serious or fatal injuries during air bag deployment appear low relative to the number of accidents with air bag deployments. To avoid air bag induced injuries, a variety of occupant sensing technologies are being developed. One of the critical logic deployment challenges faced by these technologies is whether the system can accurately determine if the occupant is in a posture or a position such that air bag deployment may result in an injury. To improve accuracy, it is necessary to understand what postures the occupants are likely to assume during a ride and how often. For this purpose, Delphi Corporation has conducted a survey to solicit opinions on the posture usage rate. With 560 responses, the frequencies for 29 sitting postures for adult passengers and 13 child postures or positions were estimated.

In this paper, dynamics and stability of an articulated vehicle in the yaw plane are examined through analysis, simulations, and vehicle testing. Control of a vehicle-trailer combination using active braking of the towing vehicle is discussed. A linear analytical model describing lateral and yaw motions of a vehicle-trailer combination is used to study the effects of parameter variations of the trailer on the dynamic stability of the system and limitations of different control strategies. The results predicted by the analytical model are confirmed by testing using a vehicle with a trailer in several configurations. Design of the trailer makes it possible to vary several critical parameters of the trailer. The test data for vehicle with trailer in different configurations is used to validate the detailed non-linear simulation model of the vehicle-trailer combination.

This paper describes a correlation study on fuel spray pattern recognition of multi-hole injectors for gasoline direct injection (GDi) engines. Spray pattern is characterized by patternation length, which represents the distance of maximum droplet concentration from the axis of the injector. Five fuel injectors with different numbers and sizes of nozzle holes were considered in this study. Experimental data and CFD modeling results were used separately to develop regression models for spray patternation. These regressions predicted the influence of a number of injector operating and design parameters, including injection system operating pressure, valve lift, injector hole length-to-diameter ratio (L/d) and the orientation of the injector hole. The regression correlations provided a good fit with both experimental and CFD spray simulation results. Thus CFD offers a good complement to experimental validation during development efforts to meet a desired injector spray pattern.