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In August of 1982, the US Army Tank-Automotive Command (TACOM), initiated the first phase of the Advanced Integrated Propulsion System (AIPS) program by awarding six design analysis contracts. The AIPS program is aimed at competitively developing and producing a power package for application to the future heavy combat vehicle weight class. This paper reviews the purpose, schedule, target goals, and acquisition strategy of the AIPS program. The AIPS development differs from past programs in several ways. Technically, the engine, transmission and other subsystems will be designed and developed together as a totally integrated propulsion system. With regard to management of the program, the Government is examining acquisition strategies with the intent of insuring competition throughout all phases (research, development, and production) and achieving the simultaneous qualification of two production sources. The final acquisition strategy has yet to be determined.

A commercial truck engine normally rated at 350 bhp was upgraded to 1000 bhp for military application. The design approach used was increased engine speed, low compression ratio, high pressure turbocharging, after-cooling and turbocompounding. This paper presents details of the performance analysis, engine modifications, and design and development of the new turbo-machinery required. Results of engine test-work are also presented.

Theories which have been proposed as an explanation of brake squeal are reviewed. It is now thought that disc brake squeal is best explained by modeling the brake as a multi-degree of freedom spring-mass system which may be stable or unstable depending on the values of its parameters. A method of testing disc brakes to measure squeal is described. Test results show that squeal is eliminated if the rotor is slotted. Test results also show that changes in friction material and pad contact geometry can have a significant effect. It is concluded that the elimination of disc brake squeal will require both better matching of the friction material to the brake, and improvements in the design of the brake.

Fuel consumption and emissions are reduced through the use of an engine/transmission management system, which prevents unnecessary engine operation. The system is described on a subcompact car with Diesel engine and economy manual transmission. During vehicle deceleration and idle modes (accelerator pedal not depressed) power transmission from the engine is interrupted and the engine is shut off. The engine is operating and power transmission to the wheels is provided only when driving force is required that means when the transmission is in gear and the accelerator pedal is depressed. The interruption and the engagement of power transmission is accomplished by an automatic clutch actuator. Monitoring and control of all system functions is accomplished by a microprocessor.

Mechanical control systems for diesel engines are reliable and exhibit a low failure rate. However, rising demands for improved functional characteristics and closer tolerances require electronic diesel control. The electronic diesel control (EDC) offers functionel advantages over mechanical controls. In order to obtain a fail-safe systems it is necessary to detect defects in sensors, in the digital processor, in actuators and in the overall system. The failure of exhaust gas recirculation is uncritical, the failure of start of injection control needs counter-measures to avoid a damage of the engine. Without countermeasures fuel delivery control failure may lead to safety risk. All required countermeasures will be explained in detail.

The diesel engine with a electronic control system which has been used in production passenger cars in Isuzu shows great advantages such as fuel economy, idle noise, cold startability and output performance by the help of the new commet V combustion chamber design. The new combustion chamber which differs in shape and throat area from the conventional commet V has been developed to be well matched to the electronic control system. The passenger car equipped with the electronic control diesel engine mentioned above provides the following four additional advantages: 1. Good acceleration response 2. Idle speed control which is affected by engine coolant temperature, on-off of the air conditioning compressor and battery voltage 3. Cruise control 4. Self-diagnostic system

The use of serial communications to route control information in an automobile can potentially provide many benefits. Serial data busses have been used in the data processing environment for many years but are unsuitable for use in real time control applications. Recently, Local Area Networks have been developed which provide the functional features required for control applications but are too expensive for use in the automobile. N. V. Philips and Signetics have applied these concepts to develop a Small Area Network capability which can be integrated onto micro-computers and other Integrated circuit devices at low cost, providing the proper cost/ performance tradeoff for their use in the automotive environment.

Improvements in disc brake friction and wear characteristics are usually sought by alternating the disc pad composition or processing conditions. This study investigated the effects of varying the cast iron rotor chemistry and microstructure on the performance and wear resistance of a disc brake composed of such rotors and standard commercial semi-metallic disc pads. A statistical design of an engineering experiment was used to determine such effects of five chemical variables of the cast iron rotor -- C, Si, Mn, P and Ti -- and two processing variables -- solidification and cooling rates. An increase in manganese or phosphorus content improved brake performance and decreased pad wear, compared to a standard chemistry cast iron. Cast irons with high titanium or carbon levels showed low friction and high pad wear. Improved performance but high pad wear were found for cast irons with high silicon contents.

Rotor surface temperatures reaching above 700°C are not unusual for heavy-duty disc brakes in service, which are used in both heavy vehicles and high-performance passenger cars. Brake rotors are conventionally composed of pearlitic gray cast iron. The over 700°C temperatures experienced in heavy-duty service cause microstructural changes in which the surface rotor material is transformed from pearl-itic to spheroidic cast iron. The objective of this study was to determine the effect of this transformation of rotor metallurgy on brake friction and wear. In this study, the normal and spheroidized rotors are coupled to a common semimetallic friction material, and the respective brake pairs are then evaluated for possible difference in friction and wear properties.

A drag test method for the quantification of front disc brake squeal which uses a brake dynamometer and noise analysis equipment was developed and previously reported in SAE Paper 820037. Subsequently, the dynamometer procedure was revised to a variable stop method which allows a wider study range in less test time while still providing sufficient information to determine the noise character influence of design changes. In conjunction with this revised dynamometer operation, a systematic vehicle test procedure was developed to more clearly define vehicle/dynamometer noise character correlation and in-vehicle noise sensitivity.

This paper provides an assessment of many factors which will be important in the successful use of magnesium in automotive components. Included in this comprehensive and extensively documented review are the subjects of magnesium availability, price, energy requirements, properties, manufacturing processes, safety and applications. Potential advantages and problems are highlighted with the hope that this information will aid in the selection and development of components which best utilize the unique characteristics of this lightweight metal.

Vehicle weight reduction accelerated in importance following the 1973 oil crisis. The Ford Motor Company reduced average vehicle weight by approximately 1000 pounds between 1975 and 1980 through downsizing, design efficiencies and material substitutions. This emphasis on vehicle downsizing and weight reduction has provided an opportunity to evaluate magnesium against conventional U.S. automotive materials.. This paper describes magnesium’s advantages and disadvantages for automotive and assesses its future role in weight reducetion. Magnesium’s potential is analyzed from a business standpoint including cost/supply, technical and timing issues.

Nisshin Steel Co., Ltd. has developed a new process for the production of a “one-side aluminized steel sheet”. The process utilizes a double layer one-side “stop-off” coating to prevent the molten Al from adhering to the steel surface. The “Stop-off” coating is removed by simple mechanical brushing after hot dipping. The characteristics of this product by above mentioned process are: 1) The steel side was as clean as a conventional cold rolled surface and showed no trace of the “stop-off” layer. Thereby, phosphating and ED painting were performed. 2) In the salt spray test data was obtained from zinc and Al coated steel surfaces; the coatings on both surfaces being of equal thickness.

A new double-layer electroplated steel sheet has been developed. The steel sheet is composed of an upper Zn-Fe (80-90%) alloy layer which has good paint adhesion and a lower Zn-Ni (10-15%) alloy layer which has good corrosion resistance. Paintability, corrosion resistance and workability of the steel sheet were investigated. This coated steel sheet was revealed to be suitable for the automobile use.

Recent trends in the automotive industry toward improving fuel economy have led to the conversion of many steel applications to aluminum. The use of aluminum reduces vehicle weight while allowing the automaker to continue to use traditional fabricating methods. The primary joining technique used for steel sheet components has been resistance spot welding. While this technique is currently used to join many aluminum components, automakers are reluctant to specify this joining technique due to capital equipment cost, electrode tip life, or reliability concerns. Several alternate joining techniques have been investigated and used. These include adhesive bonding, weld bonding, resistance welding with arc cleaning (1, 2)*, GMA spot welding, clinching, and riveting. Recently, a method of riveting components without prepunching or pre-drilling holes has generated a large amount of interest. This paper is a review of this riveting technique.

Pulsed arc welding is one of the new processes finding many applications throughout a whole range of industries. The process, which is like metal inert gas welding (MIG), produces a quality akin to tungsten inert gas welding (TIG) with consumable electrodes. The pulsed process is three to four times faster than the TIG process. Essentially, the equipment is similar to MIG welding; however, the shielding gases used are normally argon or an argon mixture. The pulsed process can be used for all-position welding of ferrous and non-ferrous materials. A distinguishing feature of the process is that large wire diameters can be operated at low welding currents. This means the cost of welding wire will be reduced (compared to standard MIG welding) and the problem of pushing aluminum wire through long conduits will be solved. The origin of the process is somewhat confusing; there are a number of patents on the process originating from the U.S. and England.

The advantages of oxide removal prior to resistance spot welding mill-finish aluminum sheet are well documented. The process of localized oxide removal through the sputtering action of a plasma arc has been integrated into a spot welding cycle at rates compatible with most automotive processes. The resulting process provides a low electrode-sheet interface resistance, having profound effects on electrode life and weld quality consistency.

In-use fuel economy shortfall varies regionally and seasonally in response to changing environmental conditions and travel patterns. Shortfall changes by 25 percent or more are associated with variations in miles travelled per day by in-use vehicles. Monthly variations in northern states are twice those in the south; air conditioning penalties also vary by region. Although regional differences in annual levels are relatively small, shortfall can increase by 16 percent in densely populated urban areas. These variations have been quantified in an analysis of time-series mpg data and related to variables commonly reported in fuel economy surveys.

To aid in better assessing the corrosion performance of AZ91 die cast magnesium, standard salt spray corrosion tests have been made on both randomly selected commercial die castings and on three series of controlled purity test panels. The results reveal that the poor performance often associated with magnesium parts in salt spray are due principally to iron, nickel, and copper contamination levels. When these contaminants were limited, severe pitting corrosion was eliminated and the salt spray performance was good to excellent when compared to 380 aluminum and cold rolled steel.

This paper assesses three factors affecting projections of passenger car fuel consumption: 1) "fuel-switching" by consumers; 2) new car fuel economy trends through 1995; and 3) the on-road fuel economy characteristics of older cars. Surveys of monthly household motor fuel purchases in 1978-1981 are used to demonstrate a significant correlation between vehicle age and trends in "misfueling". Projections of new car fuel economy are derived using a technology-oriented model previously developed for the U.S. Department of Energy (DOE). The forecasts are sensitive to fuel prices, consumer discount rates, and technology payback periods. The paper discusses the effects of changes in vehicle use intensity and odometer on the in-use fuel economy of older cars. Information also is presented on the in-use fuel economy of pre-MY1975 vehicles. The paper concludes with an assessment of the effects of these fuel economy and fuel switching trends on future automobile fuel demand.