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Technical Paper

Power Steering Pump with Enhanced Cold Start Priming

The objective of the present work was to improve the cold start NVH performance of an automotive power steering pump under low temperature conditions. This objective was accomplished through the use experimental study and measurement. The satisfactory operation of a fixed displacement vane pump in cold temperatures depends on a number of factors including; (1) filling characteristics, (2) the inlet conditions to the pump, (3) the fluid, and (4) the ability of the vanes to maintain contact with the cam surface. In this investigation, factor (4) was chosen for investigation. A unique outlet orifice was designed and tested at three different operating ambient temperatures, -19 °C, -29 °C, and -40 °C. Maximum “noise” duration was measured as the maximum duration of fluid borne pump outlet pressure oscillations greater the 345 kPa peak-to-peak. The results show that noise duration can reduced by as much as 50% at -40 °C.
Technical Paper

R134A Suction Line Heat Exchanger in Different Configurations of Automotive Air-Conditioning Systems

A suction line heat exchanger (SLHX) transfers heat from the condenser outlet to the suction gas. In a TXV (thermostatic expansion valve) system, the performance improvement with a 60 to 80 % effective SLHX is expected to be on the order of 8 to 10 % for capacity, and 5 to 7 % for COP for high outdoor air temperatures of 43ºC. In a FOT (fixed orifice tube) system, the performance improvement was calculated to be about 10 to 15 %. The calculated improvements have been verified experimentally within a few percent.
Technical Paper

Some Factors in the Subjective Evaluation of Laboratory Simulated Ride

Effects of DOF and subjective method on evaluations of ride quality on the Ford Vehicle Vibration Simulator were studied. Seat track vibrations from 6 vehicles were reproduced on the 6 DOF seat shaker in a DOE with pitch and roll as factors. These appeared in two evaluations of ride/shake; semantic scaling by 30 subjects of 6 vehicles, and paired comparisons by 16 of the subjects on 3 of the vehicles. Both methods found significant vehicle, pitch and roll effects. Order dependence was shown for semantic scaling. The less susceptible paired comparison method gave a different ordering, and is thus preferred.
Technical Paper

Automotive HVAC Flow Noise Prediction Models

Flow noise from automotive HVAC (Heating, Ventilating and Air Conditioning) systems is one of the major considerations of occupant comfort. The noise generated at high blower speed is a major contributor to the vehicle interior noise. This paper reviews automotive HVAC air rush noise prediction models for estimating register, buck (air handling subsystem) and vehicle noise levels. The vehicle noise prediction method correlates well with measured noise levels at driver right ear location: with a standard deviation of 1.31 dB where standard deviation is the difference between measured and predicted noise levels for a sample size of 10 vehicles.
Technical Paper

Fuel Economy Improvements through Improved Automatic Transmission Warmup - Stand Alone Oil to Air (OTA) Transmission Cooling Strategy with Thermostatic Cold Flow Bypass Valve

The stand alone oil to air (OTA) transmission cooling strategy with thermostatic cold flow bypass valve has been shown to be an effective means of improving the warmup of an automatic transmission. Improving the system warmup rate of an automatic transmission significantly improves its efficiency by reducing losses resulting from extremely viscous transmission fluid and can allow for calibration changes that improve overall transmission performance. Improved transmission efficiency in turn allows for improved engine efficiency and performance. The improvements obtained from increased transmission and engine efficiency result in an overall increase in vehicle fuel economy. Fuel economy and consumption are important parameters considered by the vehicle manufacturer and the customer. Fuel economy can be considered as important as reliability and durability.
Technical Paper

Water Condensate Retention and “Wet” Fin Performance in Automotive Evaporators

Water condensate retained inside an automotive evaporator has remained as one of the primary sources of unpleasant “odors”, which in turn can drive up the warranty cost for automotive manufacturers. The “wet” evaporator fin can also underperform due to the presence of condensate blocking the air passage. Moreover, condensate retention can be a potential factor of freezing up evaporators. Thus, an evaporator fin must be designed such that it can shed and drain water condensate as well as provide an excellent heat transfer capability. While the importance of water retention is well known, there seems lacking of a comprehensive way to evaluate the water retention characteristics of a particular product. In this work, attempts were made to answer four questions: (1) What is the mechanism that controls water condensate retention characteristics in an automotive evaporator? (2) Can different water retention evaluation methods reveal the same characteristics?
Technical Paper

Stability Control of Combination Vehicle

This paper discusses the development of combination vehicle stability program (CVSP) at Visteon. It will describe why stability control is needed for combination vehicles and how the vehicle stability can be improved. We propose and evaluate controller structures and design methods for CVSP. These include driver's intent identification, combination vehicle status estimation and control, and fault detection / tolerance. In this paper, the braking and steering dynamics of car-trailer and tractor-semitrailer combinations, and the brake systems which should be used extensively to increase the stability of combination vehicles are presented. Also our development platform is introduced and the combination vehicle simulation results are presented. The definition of combination vehicles in this paper includes car-trailer and commercial tractor-semitrailer combinations since their vehicle dynamics are based on the same equations of motion.
Technical Paper

Optimizing the Effects of Body Attachment Stiffness on Steering Column In-Vehicle Modes

This paper presents an unambiguous and intuitive method for identification of steering column resonant (SCR) mode of vibration. One simple but overlooked technique to determine the SCR mode in-vehicle is to provide local stiffnesses of the body locations where the Instrument Panel (IP) attaches, to the IP suppliers to be used in their design and development. This paper describes how this technique is useful in predicting the first few important in-vehicle steering column modes for different classes of vehicles, with examples presented in each class. The results obtained from such analyses are compared against those from direct in-buck simulations. This technique is not limited to its application in developing IP systems, but can easily be extended to include other systems such as seats, fuel tanks, etc. Also it is shown that a design optimization analysis may be performed using these attachment stiffnesses as design variables resulting in a system level solution.
Technical Paper

Development and Validation of a Pedestrian Lower Limb Non-Linear 3- D Finite Element Model

Lower limb injury is becoming an increasingly important concern in vehicle safety for both occupants and pedestrians. To enable vehicle manufacturers to better understand the biomechanical effects of design changes, it is deemed beneficial to employ a biomechanically fidelic finite element model of the human lower limb. The model developed in this study includes long bones (tibia, fibula, femur) and flat bone (patella) as deformable bodies. The pelvis and foot bones are modeled as rigid bodies connected to the femur and tibia/fibula via rotational spring-dashpots. The knee is defined by scanned bone surface geometry and is surrounded by the menisci, major ligaments, and patellar tendon. Finite elements used to model include 6- and 8-node solids for cartilage, menisci, surrounding muscles, and cancellous bone; 3- and 4-node shells for skin and cortical bone; and nonlinear spring-dashpots for ligaments.
Technical Paper

Portable NVH Dynamometers

Noise Vibration and Harshness (NVH) characteristics have become a key differentiator between “Good” vehicles and “Best-In-Class” vehicles. While all OEM's and most Tier 1 suppliers have on-site in-ground chassis dynamometers, a need was identified to design, develop and bring to market, a fully capable portable NVH full vehicle chassis system. The original concept entailed a device, which could be brought to the customer's location, be fully self contained, requiring no external power, and provide data acquisition using transducers that would not contact the vehicle. With traditional instrumentation taking several hours to install, non-contacting lasers would be used to provide significant timesaving, and prevent any possible damage to the vehicle from pinched wires. The new methodology should provide data acquisition in as little as 20 minutes. Analysis would be accomplished immediately following testing, with hard copies available before the next vehicle was ready to run.
Technical Paper

EVOP Design of Experiments

Evolutionary Operation (EVOP) experimental design using Sequential Simplex method is an effective and robust means for determining the ideal process parameter (factor) settings to achieve optimum output (response) results. EVOP is the methodology of using on-line experimental design. Small perturbations to the process are made within allowable control plan limits, to minimize any product quality issues while obtaining information for improvement on the process. It is often the case in high volume production where issues exist, however off-line experimentation is not an option due to production time, the threat of quality issues and costs. EVOP leverages production time to arrive at the optimum solution while continuing to process saleable product, thus substantially reducing the cost of the analysis.
Technical Paper

Evaluation of the Effect of Fuel Composition and Gasoline Additives on Combustion Chamber Deposits

Since 1992 some vehicles have experienced engine knock or rapping noise during cold starts that is caused by combustion chamber deposit interference (CCDI) To better understand the CCDI phenomena, engine dynamometer studies were conducted. Results show that base gasoline composition and detergent additive compositions have significant effects on combustion chamber deposit (CCD) build-up In addition to engine testing, thermogravimetric analysis (TGA) was used to determine a correlation between unwashed gum and CCD levels
Technical Paper

Direct Hydrogen-Fueled Proton-Exchange-Membrane (PEM) Fuel Cell for Transportation, Part 2

A fuel cell (FC) powerplant is an electrochemical engine that converts fuel and an oxidant electrochemically into electric energy, water and other chemical byproducts. When hydrogen is used as the fuel, the only products of the electrochemical reactions are water and electric power. Other conventional and advanced powerplants for transportation, such as the internal combustion (IC) engine, the Diesel engine and others, are thermal combustion engines. The theoretical or thermodynamic efficiency of a fuel cell or electrochemical engine is much higher than the thermodynamic efficiency of a heat engine. The practical efficiency of a fuel cell is highest at partial load, whereas the practical efficiency of a heat engine is highest at maximum power. A survey is presented of the different fuel cell types and their characteristics. The proton-exchange-membrane (PEM) fuel cell is shown to be the best available fuel cell for transportation applications.
Technical Paper

Modeling the Effects of Intake Flow Structures on Fuel/Air Mixing in a Direct-injected Spark-Ignition Engine

Multidimensional computations were carried out to simulate the in-cylinder fuel/air mixing process of a direct-injection spark-ignition engine using a modified version of the KIVA-3 code. A hollow cone spray was modeled using a Lagrangian stochastic approach with an empirical initial atomization treatment which is based on experimental data. Improved Spalding-type evaporation and drag models were used to calculate drop vaporization and drop dynamic drag. Spray/wall impingement hydrodynamics was accounted for by using a phenomenological model. Intake flows were computed using a simple approach in which a prescribed velocity profile is specified at the two intake valve openings. This allowed three intake flow patterns, namely, swirl, tumble and non-tumble, to be considered. It was shown that fuel vaporization was completed at the end of compression stroke with early injection timing under the chosen engine operating conditions.
Technical Paper

Driver Eye Height and Sight Distance on Vertical Curves

Analyses were performed to determine the sensitivity of stopping sight distance on vertical curves to driver eye height and other parameters entering into the stopping sight-distance equations. Sight distance was found to be relatively insensitive to eye height. On a given hill crest, sight distance for a driver whose eye height is 6-inches lower than the design eye height (3.75 ft) is only 5% less than the design sight distance. On the other hand, stopping distance is very sensitive to travel speed, pavement friction and reaction time. For example, a 1.8 mph decrease in speed reduces stopping distance by the same amount that a 6-inch decrease in eye height reduces sight distance. Also, sight distance is about 2.5 times more sensitive to obstacle height than eye height. It is argued that reductions in travel speed since the introduction of the 55-mph speed limit compensate for any recent or projected decreases in driver eye height.
Technical Paper

Ford “S” Frame

Since statistics indicate that front impact is the major accident type, Ford has been studying energy-absorbing structures for some time. Early designs such as the “ball and tube” and “rail splitter” were discarded in favor of the “S” frame. Details of the design approach and testing are given in this paper. Design objectives were increased effective collapse distance, compatibility with production practices, and maintenance of satisfactory noise, vibration, and harshness levels. Safety objectives are improved passenger compartment integrity and reduction of seat belt loads. Barrier crash tests at 30 mph (equivalent to collision into standing vehicle at 50 mph) were used to evaluate the design of the “S” frame. Results of testing indicate that occupant restraint with seat belts, combined with front end structural improvements, offer the most promise for injury reduction during service front impact accidents.
Technical Paper

The Ford 427 Cubic Inch Single Overhead Cam Engine

Continuing demands for performance improvements in passenger car engines led to the development of the Ford 427 cu in. single overhead cam engine. See Fig. 1. Author discusses manner in which development of this engine was accomplished, using several design parameters, which included new and previously proved features.
Technical Paper

Performance and Economic Objectives for Over-the-Road Powerplants of the Future

The purpose of this paper is to project the performance and economic objectives of over-the-road powerplants in the decade of the 1970’s. The influencing factors for this projection are trends in: intercity ton miles of freight, size and weight legislation, the interstate highway system maximum legal speed laws, and operating costs of interstate carriers. These factors set the stage and establish the horizon for over-the-road vehicles of tomorrow.
Technical Paper

Recent Developments in Penetration Resistance of Windshield Glass

A twofold improvement in penetration resistance of laminated safety glass for use in vehicle windshields has been achieved. A new test procedure has been established which will provide better correlation of test conditions to accident conditions than present tests do. Present windshield material and the new safety glazings are compared.
Technical Paper

Combustion Chamber Effects on Burn Rates in a High Swirl Spark Ignition Engine

Experimental measurements of burn rates have been carried out in a single cylinder homogeneous charge engine. Three different combustion chambers were investigated (75 % and 60 % squish bowl-in-piston chambers and a disk chamber) using a cylinder head with a swirl producing intake port and near central spark location. Data were obtained with each combustion chamber as a function of spark timing, EGR, and load at 1500 RPM. The combustion rate is strongly influenced by chamber shape. The 10-90 % burn durations of the 75 % and 60 % squish chambers are respectively about 40 % and 60 % that of the disk chamber. Chamber configuration had less effect on 0-10 % burn duration. The disk had about 25 % longer 0-10 % burn time than the bowl-in-piston chambers. Modifications to the GESIM model enabled good overall agreement between predictions and experimental data, a rather severe test of the model because the coupling of fluid mechanics, combustion and chamber geometry must be properly modeled.