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Technical Paper

Modeling, Simulation, and Control Implementation for a Split-Torque, Geared Neutral, Infinitely Variable Transmission

1991-02-01
910409
Split-torque, geared-neutral transmissions have been shown to improve vehicle performance over a conventional continuously variable transmission. Although control of these transmissions has presented significant problems in the past, we have been able to achieve good driveability and fuel economy through the use of an integrated engine/transmission control philosophy. Development of the transmission/engine control strategies are based on detailed dynamic models and computer simulations of the driveline. In developing the control laws, specific attention has been given to providing characteristics similar to that of a conventional automatic transmission, such as creep and hill-holding capabilities. Test results show adequate transmission response with high initial jerk if demanded, excellent stability at the geared-neutral point, and smooth transitions through the synchronous point as well as in all other driving conditions.
Technical Paper

Properties of Magnesium Plaster Castings

1991-02-01
910413
The demand for magnesium prototypes is growing very rapidly with the increasing number of new applications for magnesium die castings. Plaster mold casting is becoming more used amongst all other prototyping methods because it can produce castings with thin walls, smooth surface finish and close dimensional tolerances. However plaster mold casting of magnesium alloys has only been used until now by a few foundries because of the risks of violent reaction if the process is not carefully controlled. For this reason, very little quantitative information about properties of plaster cast magnesium alloys is available in the literature. In this study, mechanical, corrosion resistance and microstructural properties of alloy AZ91E are reported as a first phase of the work being conducted at the Institute. As cast (F), solution annealed (T4) and solution annealed and aged (T6) properties of 12,5 mm (1/2 inch) diameter test bars were studied.
Technical Paper

Stress Relaxation Behavior of Die Casting Alloys

1991-02-01
910412
The phenomenon of stress relaxation in a solid corresponds to a time-dependent decrease in stress under given constraint conditions. An apparatus for stress relaxation compression testing was constructed and utilized to evaluate a series of die cast magnesium alloys. The behavior of the alloys was determined over a 100 hour test period. In general, the percentage of stress remaining after this time decreased with increased initial stress and with increased test temperature. Of the materials tested, magnesium alloy AE21 showed the best relaxation resistance relative to 383 aluminum alloy.
Technical Paper

Development of a Thermoplastic Composite Kneebolster

1991-02-01
910405
A first surface thermoplastic composite knee bolster system has been developed by Chrysler Corporation for the Eagle Premier vehicle, resulting in a major breakthrough for occupant safety interior design. It provides significant weight and cost savings versus the multi-piece steel assembly it replaced. This new design, in conjunction with a motorized two (2) point seat belt system, meets all FMVSS 208 requirements for occupant protection and safety.
Technical Paper

Thermoplastic Glass Mat Reinforced Knee Bolster Development

1991-02-01
910403
Abstract The desire to combine the roles of the instrument panel carrier with structural functions traditionally fulfilled by steel reinforcement and tie bars provided the catalyst to search for a material and construction capable of combining the advantages of plastic processing with the structural characteristics of steel. Candidate materials and constructions were initially judged against a criteria list of design flexibility, tooling cost and leadtime, piece cost, developmental leadtime, product maturity, weight,and physical properties. The most promising alternates were tooled and tested with a knee impactor and a barrier sled in order to assess performance to occupant safety objectives. Ultimately, a thermoplastic composite proved capable of meeting all the structural requirements while enhancing design flexibility and reducing tooling leadtime and cost, piece cost, and vehicle mass.
Technical Paper

A Geared Infinitely Variable Transmission for Automotive Applications

1991-02-01
910407
Epilogics, a young engineering firm in Los Gatos, CA, has developed the first fully-geared, high torque, high efficiency, infinitely variable transmission (IVT) suitable for automotive applications. To prove its torque capacity, Epilogics demonstrated a prototype of its patented transmission concept in a Class VII diesel truck in June, 1989. In addition to being ideally suited as a transmission for motor vehicle drivetrains, the IVT can provide a means to efficiently and flexibly drive engine accessories independently of engine speed. Products have already been designed or built to drive alternators at a constant speed (irrespective of engine/vehicle speed) and to control cooling fan speeds independently of engine/vehicle speed. Outside of automotive applications, experimental designs of automatically adjusting manual sailboat winches and continuously variable bicycle transmissions have been implemented.
Technical Paper

Hybrid Charging System for Heavy Duty Diesel Engines

1991-02-01
910419
In Japan, the next stage exhaust gas emission registration will be introduced around 1994. In case of heavy duty diesel engines, the level of NOx will be limited to 6.0g/kWh and the limit of particulate will be added to it. Its limit will be 0.7g/kWh. In U.S.A, regulation of particulate was already effective in 1988 and it will be tightened in 1991 and 1994. To pass these regulations, turbocharging with an intercooler is recommended to increase air flow, because reduction of black smoke at high load condition will be achieved by the improvement of combustion process. Also it will reduce negative effects by retard of injection timing that reduce NOx level. Although this improvement will be effective over approximate 1000rpm of engine speed, it will not be effective under 1000rpm because an engine can not get sufficient air flow due to poor performance of a turbocharger at this range. This is still one of unsolved problems at present.
Technical Paper

Second Law Analysis of Turbocharged Engine Operation

1991-02-01
910418
In this paper the turbocharged diesel engine operation is analyzed by means of a second law based method. The instantaneous release and storage of availability inside the several components (cylinders, manifolds, compressor and turbine) are evaluated by following a theoretical-experimental methodology that has been recently proposed by the authors. Examples of availability balances are compared for different values of some parameters which influence the combustion and the exhaust process, or for several arrangements of the engine and turbomachine system. The availability analysis of the engine transient development will show the amounts of mechanical energy employed for both in-cylinder storage and turbocharger acceleration and of those available for conversion into external output. These amounts will be compared with the fuel availability and with those destroyed during the several processes (i.e. combustion, gas exchange, turbocharger operation).
Technical Paper

Development of the Mitsubishi TF07 Model Turbocharger for 1994 U.S. and 1993 European Diesel Emission Standards

1991-02-01
910422
1. ABSTRACT: The exhaust emission gas regulations on truck diesel engines are becoming increasingly stringent in various countries in the coming years. The '94 EPA (U.S.A.) regulations include the entire working range of engines, including transient conditions; thus requiring a large-scale improvement in engine properties. For this reason, various engine components are now undergoing a series of improvements; in particular, the injection system has experienced a major renovation. However, the improvement of a naturally-aspirated engine has its own limit; and the turbocharged engine with inter-cooler becomes essential. Mitsubishi Heavy Industries has been pushing ahead with the development of turbochargers for use with the truck diesel engines. To assist the Diesel engine manufacture to meet these new emission regulations, we have developed various turbocharger options for improving engine performance, in addition to our continuing efforts for improving the aerodynamic properties.
Technical Paper

An Intake Charge Cooling System for Application to Diesel, Gasoline and Natural Gas Engines

1991-02-01
910420
Low intake manifold temperature, well below ambient, has many applications in internal combustion engines. In diesel engines, it can reduce NOx to a level of 2.0 g/hp-hr or below, going beyond the 1994 heavy duty diesel engine emissions standards. In gasoline engines, it can allow high compression ratio, turbocharged operation without end gas knock. This will permit ready conversion of some heavy duty diesel engines to gasoline operation at increased power density and lower emissions. In natural gas engines, it will allow base diesel engine to be converted to stoichiometric natural gas operation without increasing thermal loads. A three way catalyst can then be used to reduce emissions.
Technical Paper

Creep of Diecast Magnesium Alloys AZ91D and AM60B

1991-02-01
910416
Long term creep tests of diecast AZ91D and AM60B were conducted for periods of 30 days to nine months at temperatures up to 150°C. Stresses from 19 to 111 MPa were employed. Thermally activated creep did not occur when the temperature was below 100°C and the stress below 25 MPa. Under these conditions the creep rate eventually diminished to zero. AZ91D metal matrix composite specimens reinforced with 15 volume percent silicon carbide creep tested at 150°C exhibited much improved creep resistance over monolithic AZ91D.
Technical Paper

Machining Magnesium With Water Base Coolants

1991-02-01
910415
Magnesium Products Limited has been very successful in converting from machining magnesium die castings dry to machining with oil-in-water emulsions, more commonly called water soluble oils. When machining with water soluble coolants one can expect; 1) excellent fire protection; 2) improved tool life; 3) ease of housekeeping, and 4) improved productivity. Problems previously encountered with water soluble coolants such as splitting out of solution, hydrogen gas generation, and salt deposits on tools and machines have been singled out and addressed, with solutions tested in production environments.
Technical Paper

A Small Turbocharger for Passenger Car and Truck Applications

1991-02-01
910421
The Garrett Automotive Group of Allied-Signal, Inc. has developed a new small turbocharger to meet a worldwide demand arising from the need for fuel efficient and low emission small engines for passenger cars and light trucks. This new turbocharger, designated the GT15, is smaller, lighter and lower in cost than Garrett's successful T2 turbocharger and is also designed to meet the more stringent durability requirements of the future.
Technical Paper

A Regenerative Active Suspension System

1991-02-01
910659
Abstract Active automotive suspension systems have been under development for a number of years with recent introductions of various versions. A suspension system can be considered “active” when an outside power source is used to alter its characteristics, and these systems can be placed into one of three (3) different categories: semi-active damping, fully active, and low frequency active. A regenerative pump concept can minimize the power requirement for the low frequency active system. It utilizes four (4) independent variable displacement pump/motor combinations on a common shaft to actuate each individual suspension unit. This paper overviews the system configuration, describes the power and energy-saving features of the system, and discusses possible pump configurations and control strategies.
Technical Paper

Crash Recorder for Safety System Studies and as a Consumer's Product

1991-02-01
910656
CRASH RECORDER FOR SAFETY SYSTEM STUDIES AND AS A CONSUMER'S PRODUCT - This paper first describes a joint development project between Mannesmann Kienzle GmbH and VOLVO Car Corporation regarding an advanced Crash Recorder (CR) to be installed in the vehicle test fleet by VOLVO. The objective of the project is mainly to gain experience concerning the correlation between crash severity, vehicle damage and bodily injuries of the occupants by getting access to extensive and accurate in-vehicle data from reallife accidents. The Crash Recorder monitors and records a number of variables during the phases of pre-impact, impact and postimpact. Parallel to this device a low-cost consumer's device has been developed by Mannesmann Kienzle and the full concept of this device will be presented. The objective of this low-cost Accident Data Recorder (ADR) is to provide a qualified in-vehicle monitoring system providing vehicle trajectories data for direct use in computeraided accident reconstruction.
Technical Paper

A New Automobile Crash Sensor Tester

1991-02-01
910655
This paper examines how crash sensors are tested and describes a new general purpose impact machine which can be used. The paper describes the pulse shapes in common use (haversine and half sine), pulse accuracy, longitudinal and cross-axis vibrations and pulse durations and how this machine performs these tests. Other tests including pulse angularity, temperature, vibration and other environmental tests. Finally, this paper discusses available sensor test equipment from the standpoint of pulse accuracy, data acquisition accuracy, pulse amplitude and duration capability, coast or dwell capability, the ability to simulate an actual crash pulse, ability to impose cross axis vibrations and the ability to test against a mathematical model.
Technical Paper

Integrated Occupant-Car Crash Simulation with the Finite Element Method: The Porsche Hybrid III-Dummy and Airbag Model

1991-02-01
910654
The work involved in laying out restraint systems for motorcars can be supported by numerical crash-simulations in the concept-phase. A prerequisite is that the interactions between dummy and vehicle structure are determined under realistic conditions. It is then possible to reduce time, costs and finally the development risk, because the subsequent safety tests with car prototypes can be realized with already optimized components. Until now the simulation of vehicle structure and occupant behaviour was realized very often sequentially in succession, that means without consideration of interactions between vehicle structure and occupant. First acceleration histories of the passenger compartment were determined by simulation of the vehicle structure with the Finite Element Method (FEM). These results were used as input for Crash Victim Simulations (CVS).
Technical Paper

Improvement of Vehicle Motion and Riding-Comfort by Active Controlled Suspension System

1991-02-01
910662
The adaptation of the active control technology to practical suspension systems of vehicles has remarkably improved the safety and ride-comfort of vehicles. This paper presents a study on the practical realization methods of an active suspension system that combines high response and low energy dissipation. The effects of active control on the stability of vehicle motion and ride-comfort were investigated by practical tests using an experimental vehicle. The integrated active suspension system consists of a motor-controlled oil pump, which is active power source, and a motor-controlled variable orifice, which is semi-active adjustable element. Multi-controller computer systems for individual controls of each suspension unit and an integrated control of the whole body behavior are also installed.
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