Search Results

This project was initiated to determine the effect of regular Car washings upon the retardation of corrosion on automobiles. A periodic problem is present in northern climates where, during the winter months, roads are often laden with salt to prevent icing of the streets. Some of the salt will become deposited on the car with accompanying possible corrosion problems. Furthermore, when the vehicle is taken to a commercial car wash establishment, the salt will become incorporated in the recycled water to be used in washing of other cars. Whether this chloride content build-up in reclaim water in northern car washes is significant needs to be determined. Thus, there are two sources where corrosion is a potential problem.

For the first time a statistically valid survey and sampling of the engine coolant has been taken of the United States passenger car population covering model years 1980 through 1968 and older. The purpose of the survey was to assess the coolant inhibitor condition, glycol concentration, coolant level, and performance history in passenger cars as they prevail in all parts of the United States. A circulated warm coolant sample was taken from 1004 engine cooling systems. The samples were evaluated for rust and/or sediment, and analyzed for pH, reserve alkalinity, percent glycol, and iron concentration. The car operator was interviewed for a history of coolant maintenance and engine cooling performance problems. The information from this unique survey clearly indicates the current quality of engine coolant condition and how it relates to the major geographic segments of the country.

The use of a corrosion inhibited arsenical brass alloy for copper/brass radiator tubes has been identified as an effective means to protect the radiator tubes from external dezincification attack, which is generally caused by an exposure to excessive road salts in the regions such as Montreal and Toronto in Canada. Laboratory test methods, their results and field data verifying improved radiator life are presented.

While corrosion in general is a subject of considerable interest to automotive engineers, corrosion related failures of components which may affect safe vehicle operation often generate intense investigation due to their ramifications. Manufacturers take considerable precautions to avoid these situations and so their occurrence is usually the result of an unexpectedly severe environment or an unfamiliar corrosive mechanism. The failure of suspension and brake system components, fasteners and seals is discussed with emphasis on the corrosion machanisms and service environments. A wider dissemination of this information may permit design engineers to avoid these problems in the future.

Should you utilize after-market Rustproofing on your fleet equipment? This question is one of the many that must be answered by Fleet Managers when they purchase new equipment. The purpose of this paper is to discuss some of the key points to be considered in answering that question, and how to set up an effective Rustproofing Program.

The recent trend in the automotive industry toward improved safety and reduced weight has led to the increased use of high strength steels in parts that were formerly made of mild steel. As part of an evolutionary substitution technology, it is necessary to evaluate as critically as possible the components where high strength steels are most effective. This paper presents a methodology to predict the potential for thickness reduction when using high strength steels in fatigue critical applications. With the growing emphasis on the finite-life design concepts, the methodology makes use of strain-life parameters for predicting thickness reduction. The role of stress concentration at notches is also highlighted. The methodology is illustrated with data for several hot-rolled, cold-rolled, and galvanized high strength steels.

Samples of cold rolled and hot dip galvanized mild steel, microalloyed high strength steel, and dual phase steel were prestrained by bending and straightening, bending and straightening with superimposed tensile strain in a die, and cold rolling (dual phase steels only). In all three cases, the strain state was approximately plane strain. Stress-strain behavior was evaluated by conventional tensile testing of as-received and prestrained samples. For the mild and the high strength microalloyed steels, it is shown that the use of effective prestrain calculated assuming isotropy coupled with simple parabolic work hardening provides reasonable engineering estimates of the yield and tensile strength after prestraining if κ and n are taken from as-received tensile tests oriented coaxially to the restrain direction. It was also found that in bending and straightening, only the absolute average value of the bending strain should be used in calculating the effective prestrain.

Dual-phase steels have been used primarily for reducing weight of complex shaped automotive parts which could not be made with less formable, conventional high strength steels. Recently, a microalloyed dual-phase steel was found also to possess superior machining characteristics. This paper describes laboratory data which compare machinability of dual-phase steel with that of conventional steels. The effects of material strength, tensile prestrain, and cutting depth on machined surface quality are elucidated. The improved machinability of dual-phase steel was explained on the basis of its unique micro-structure. In addition, two applications of dual-phase steel are discussed. In one application, broaching is the critical machining step, and dual-phase steel is currently used in production. In the other, turning is the critical step, and further studies are under way.

In order to help the gauge reduction of wheels and chassis parts of automobiles, a form-able and weldable hot rolled steel of 550 MPa grade, named FDP-55, has been developed. FDP-55 is an 0.14% C, 0.1% Si, 1.1% Mn and Nb free A1-killed steel obtained by controlled-cooling to a low coiling temperature on a runout table, and it is featured by ferrite-degenerated pearlite microstructure. Results of co-operative works with automotive makers showed that FDP-55 was successful in the application to wheels and chassis parts attaining the large weight reduction. This paper reports the metallurgical features and characteristics of the steel.

Sintered silicon nitride (SSN) was advantageously applied for turbocharger rotors owing to its light weight and excellent high temperature strength, which would provide a better response and a high temperature capability. SSN rotor have been fabricated by injection molding, sintering, machining, balancing and inspecting processes. Rotor construction could be shaped either monolithically or by bonding the turbine wheel with shaft. Cold and hot spin testing have been carried out. The highest tip speed observed was 580 m/sec at 750°C without failure.

This paper documents the successful operation of a modified Cummins T46 turbocharger with a ceramic rotor. This turbocharger is modified to incorporate a 4.6 inch diameter ceramic turbine rotor (pressureless sintered silicon nitride) on the hot end. These results document the most complete ceramic turbine rotor performance map, for a large ceramic turbocharger rotor, available to date.

Despite the significant advances that have been made in understanding the aerothermodynamics of the radial flow turbocharger components, particularly during the last two decades, such problems as the turbocharger effectiveness at low engine speeds, inadequate flow range, turbocharger lag, etc., continue to arouse concern. The paper examines the pros and cons of the various candidate schemes to solve these problems.

A historical review of Japanese turbocharged diesel engines for heavy duty vehicles is described, and newly developed turbocharged diesel engines of HINO are introduced. The design features of these engines include new turbocharging technologies such as highly backward curved impeller for compressor blade, variable controlled inertia charging and waste gate. Laboratory and field test results demonstrated better fuel economy and improved low speed and transient torque characteristics than the predecessors. Several operational experiences, technical analysis and reliability problems are discussed.

This treatise addresses the state-of-the-art in dynamic sealing systems for commercial vehicles. A brief review of different seal types is given and a 12 year literature search is included in the references. The scope of the paper, however, is limited to radial lip and mechanical face seals. The lack of understanding of the sealing mechanism is noted. Also discussed are the effects of various design factors; application factors which need specific attention; materials; testing methods; and the need for realistic standardized tests. Field tests are used as the final approval for seal applications, but qualification tests for the same type of application vary widely. Future work should be directed towards understanding the sealing mechanism.

A single cylinder water cooled prechamber diesel engine was used to evaluate SRC-II coal derived fuel with respect to performance and emissions. SRC-II could only be burnt in blend with diesel fuel. Changes of characteristics were shown in relation to SRC-II blend ratio. About 25% blend of SRC-II was the limit available to the contemporary prechamber diesel engine. It was defined that cetane improver and heat insulation of prechamber were effective to expand operating range for low cetane fuel.

Solvent Refined Coal (SRC II) was evaluated for its acceptability as alternate fuel for a spark assisted multifuel diesel engine which was modified to accept a spark plug in the swirl chamber. The objective of this study was to determine the effect of the use of SRC II on performance and emissions of the spark assisted swirl chamber diesel engine in comparison with diesel fuel operation. The results showed that SRC II could be used on the spark assisted diesel engine with engine performance comparable to that with conventional diesel fuel when the engine operating condition was optimum. However at other engine operating conditions large increase of unburned hydrocarbon and particulate emissions was found when operated with SRC II.

Vegetable oils provide diesel engine performance similar to that obtained with diesel fuel, and this has been documented in many prior publications. Because they are potentially interchangeable with diesel fuel, interest has focused on vegetable oils as short-range alternate fuels. However, engine durability when burning vegetable oils may be adversely affected depending on the type of combustion system employed. Laboratory and field experimental tests have identified the prechamber engine as having the greatest short-range potential for using vegetable oil fuels. Performance and durability at low engine ratings are essentially the same as expected for operation on diesel fuel. However, at high engine ratings piston ring and cylinder liner wear are greater than expected for operation on diesel fuel.

The paper reviews the literature for methods of increasing fuel flexibility in diesel engines over a range of fuel properties representing alcohols to high viscosity diesels. It was conceived that the details of fuel-charge within the engine cylinder would help evaluate the requirements for multi-fuel engine design. It is therefore, attempted to model in-cylinder flows, fuel-air mixing and fuel property effects. The preliminary results of these calculations are presented.

The following investigation was carried out to evaluate work hardening and bake hardening in actual body components. Five pressings were made from mild steel and three different grades of high-strength steel with ultimate tensile strengths ranging from 380 to 470 N/mm2. The latter were a batch annealed Rephos steel and two other grades of continuously annealed dual-phase (DP) steel. Tensile test specimens were taken from these components to evaluate the work hardening and bake hardening. The results are contained in the report. A new Volvo standard for high-strength cold-rolled sheet steel has been introduced. To some extent, the formulation of the standard was based on the results of the investigation of work hardening and bake hardening. The form and application of the standard are described in the report.

The paint bake strengthening, i.e., the increase in yield strength due to strain aging during the paint curing cycle, can be used to achieve additional strengthening in formed steel parts. Many parameters affect this strengthening in water quenched continuously annealed steels. This paper describes the effects of quenching and overaging temperatures, the mode and direction of deformation, manganese level, and the nature of microstructures on the paint bake strengthening in continuously annealed steels. The most important parameter affecting the paint bake strengthening is the overaging temperature. It is shown that for temper rolled steels overaged below 274°C (525°F), introduction of a certain minimum strain during stamping is not necessary to take advantage of the paint bake strengthening. Also, paint bake strengthening in partially recrystallized and fully recrystallized dual phase steels are found to be comparable.