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A new concept of integrated sealing systems for shock absorbers in vehicle suspensions has been developed in an attempt to add value to the product. This new sealing system concept is based on incorporating several separate components into one unique assembly.

Surface scuffing related to gas nitrided piston rings is attracting more attention as the effective cylinder pressure is increased in the recent years. However, the mechanism behind scuffing induced in long-term operations remained unknown. This study focuses on clarifying the mechanism behind scuffing related to gas nitrided piston rings. In addition, application of a thin composite plated surface film containing dispersed particles is proposed as an effective measure for preventing surface scuffing during long-term operations. Furthermore, factors enabling maintenance of high scuffing resistance on the ring surface after the thin plated composite film wears off and the underlying nitrided surface is exposed were analyzed. The dominant factor was discovered to be the difference in the resulting sliding surface profile, after initial wear, between a ring surface with composite plating and a ring surface with only gas nitriding treatment.

The nitriding process improves in some applications the fatigue resistance of mechanical components. There is a lack of information about the nitriding process effect on the toughness of components. It is well known that the austempering heat treatment improves the toughness of the nodular cast iron. Some efforts have been made to find a compromise between the toughness of the bainitic structure of nodular cast iron and the high wear resistance undertaken by the nitriding process. Nitriding causes smaller dimensional problems if compared with other termochemical processes in steel and cast iron, but during exposure to the nitriding temperature the stabilized austenite of the nodular cast iron bainite may decompose, and induce component distortion. It is well known that the stabilized austenite is responsible for high toughness of the nodular cast iron.

Nowadays the widespread use of Diesel engines in trucks and buses in our cities makes desirable any improvement in the engine reserves concerning emission and performance. We developed a Light Load Timing Advance (LLTA) on plungers of engine's pump OM366LA - Mercedes Benz that greatly increases the engine reserves by an optimization of the injection pump's hydraulic. The improvement were: better fuel consumption, lower white smoke and reduction of smoke in free acceleration tests.

Introduction of the relevant ergonomic concepts recommended for the development of automotive electrical switches, giving to the design engineer criterias for better integration and interface Man-Machine

Recently, Gasoline Direct Injection (GDI) engine has reached mass production. Fuel economy up to 35% is claimed, at urban driving conditions, by using stratified charge combustion. It also reduces HC emissions at cold start. Most of the car manufactures are researching GDI or even intend to produce it in the near future. If the promised goals are actually achieved, a great change in the development focus for automotive engines will occur. In GDI engines, ultra lean burn, stratified charge combustion is achieved by injecting fuel directly into the chamber during compression stroke (“late Injection”). In contrast, at higher power conditions, the GDI operates in homogeneous charge and fuel is injected during intake stroke (“early injection”). This paper intends to summarize some information about Gasoline Direct Injection engines and possible effects on Piston rings. First, some basic concepts about combustion, judged to be necessary to understand GDI engines, are introduced.

A computational fluid dynamics (CFD) analysis of the M366LAG in-cylinder flow was performed to explain what are the reasons for the measured engine slower combustion which results from the replacement of the intake valve seat angle of 45° by 20°. Simulations showed that a quite different in-cylinder flow resulted from the different designs. The 20° geometry was found to generate a weaker turbulent field at the end of the compression stroke, specially around spark plug, which was identified as the cause of the slower combustion. The weaker turbulence is a result of a less coherent flow structure which is less capable of both storing the main flow kinetic energy until the compression stroke end and of taking advantage of squish to generate turbulence.

Qualitative evaluation of over 100 heat shields was completed with the use of K-Flow 1.0, a Windows based computer program developed by Thermal Ceramics. These evaluations were designed to eliminated some of the cost incurred in developing and testing new heat shield configurations by narrowing the amount of actual lab testing required, K-Flow 1.0 offers a logical focused starting point while allowing for inexpensive investigation into other thermal containment alternatives. The empirical evaluation of various heat shield characteristics and how they relate to differential temperature provided several qualitative conclusions. The expected increased in differential temperature( a lower cold face temperature for a given hot face) was seen for increasing thickness and density.

At the present time, as the world's vehicle population inches over 700 million, countries around the world are continuing to struggle with their motor vehicle pollution problems. Some countries have made great progress in reducing CO and HC emissions from vehicles, and to a lesser extent NOX, in spite of substantial growth in their vehicle populations. While car standards continue to be pushed, the motor vehicle focus is gradually shifting to heavy duty trucks and buses and off road vehicles and engines. Fuels improvements are also playing an increasingly important role. Finally, concerns with CO2 and other greenhouse gases are getting increased attention. The purpose of this paper will be to provide a broad overview of these developments, highlighting the successes achieved to date and the future challenges.

The Allison MT643R is a fully automatic transmission with integral input retarder that has been designed and developed for the Latin American city bus market. This transmission provides a cost effective manner to integrate secondary braking into an automatic transmission to lower overall life cycle costs for the city bus. It provides the ease of operation of the fully automatic transmission while providing a system that will enhance vehicle braking and safety while saving on brake system repairs - all in one package. The MT643R has a 250 horsepower input retarder which has a two-stage capacity that, in conjunction with the gear multiplication through the drivetrain as the transmission downshifts, allows for tailoring of the retardation performance to very specific duty cycles. This paper will discuss the design, development, and specific product launch of the MT643R into the Latin American marketplace.

A great deal of problems occurring with several commercial vehicle marks world-wide is the frequent failure in rubber material of the pneumatic rubber of brake circuits. The most frequent fails observed in the field are: valves stuck, rubber wear off, rubber rupture and softening degradation. In order to determine the causes, studies were developed in laboratory following the formation of esters, searching for its effects and submitting the pneumatic rubber valves to direct contact and finally comparing the data with valves aged on the field.

The dependence of the turbulent flame speed and the flame development angle on air-fuel ratio, engine rotational speed, ignition timing and compression ratio has been verified. An isooctane-fueled research engine has been utilized in the experiments. The turbulent flame speed and the flame development angle have been determined with the aid of a spark ignition engine cycle simulation model. The results from this work confirm existing theories on the influence of engine design and operating parameters on the turbulent flame speed and on the flame development angle, but suggest the way they relate is to be better established. The effects of knock and incomplete combustion have also been examined.

NEW LINEAR AND NON-LINEAR TAILORED BLANKS - A NEW CLASSIFICATION ACCORDING TO THEIR MANUFACTURING PROCESS In the past years the number of tailored blanks has been continuously rising in Europe, United States and Japan. From its initial beginning in 1979 at Volvo Sweden, the tailored blank applications include now rails, columns, door inner panels, wheel houses, floors, rocker panels, cross beams, shelf panels, hood reinforcements and body side rings. They all have one common feature: straight respectively linear welds. In the automotive industry the new buzz word is «non-linear welds». The reasons for non-linear welds are such as improved stampability by moving the weld seam away from the critical areas lighter tailored blanks by using only thicker gage material only where absolutely needed and inserting pockets of thicker gage sheet metal in order to valuate the impact of non-linear welds.

This paper describes the autodeposition process, with particular emphasis on new applications of the technology. A worldwide increase in environmental restrictions for the coatings industry has led many automotive related companies to examine the characteristics of all processes used. The environmental effects of the autodeposition technology are reviewed and compared to conventional coating processes. The process is examined from a practical viewpoint. The technical and economic requirements for the application of the technology in a typical metal coating application are described. The operational aspects of the different process steps are considered, and the manpower and maintenance requirements detailed. To conclude, a summary of end user specifications and applications is presented.

A model for piston slap force level prediction is being developed. The development project is scheduled to be carried out in three distinct steps, which are discussed here. Step one and part of two have already shown important features of the role of the oil film on the impact behavior. The Reynolds theory has been applied and a preliminary prediction model proposed. The piston-cylinder, wall-engine block structure is treated as 7 degree freedom system.

Catalytic performance can be improved by reducing bulk density (BD) and increasing geometric surface area (GSA) of ceramic substrate. Ultra thin-wall / high cell-density ceramic substrates, such as 3 mil/ 600 cpsi and 2 mil/ 900 cpsi have improved the catalytic performance over the conventional 6 mil/ 400 cpsi substrates. and are expected to help in complying with future emission regulations, as well as catalyst down-sizing. This paper describes the effects of BD and GSA using Pd-based catalysts. The significant reduction of hydrocarbons emissions was demonstrated at close-coupled location, and dual bed design was proven effective. The effectiveness at under-floor location was not as significant as the close-coupled location. This paper proposes the converter layout of dual bed close-coupled converter consisting of small volume 2 mill 900 cpsi front catalyst and large volume 3 mil/ 600 cpsi rear catalyst.

In the global economy, the companies' competitive advantage is directly connected with its capacity to develop new products. So, the professionals' formation, which is part of this development, needs to be one of the main concerns of the companies. This is necessary for the benefits of the techniques and tools of Concurrent Engineering, as well Concurrent Engineering itself, to be extracted. In this context, it was developed at the Integrated Model Factory), at USP/São Carlos, an Environment that uses new education methods to form professionals with knowledge to face these new challenges.

The torsional damper of a vehicle's clutch is, as part of the drive train, subjected to various dynamic loads. Increasing torques and spatial limitations call for lightweight construction. The design of these components is now increasingly being influenced by the need to consider them from an fatigue strength standpoint. A new testing concept which aims at providing evidence of fatigue strength is introduced here, taking commercial vehicle clutch disks as an example, and touching upon the areas of analysis and evaluation of the load collective characteristic and of control systems for servo-hydraulic test rigs.

This paper describes a way to provide a more precise evaluation of the ride of after market suspension systems for four wheel drive vehicles. It explains the use of a Data Logging System and the Analysis of data retrieved by this system to set guidelines to aid in the development of new after market suspension (shock absorbers, springs, sway bars). The use of Data Logging Systems (used extensively on race cars in recent years) for this area of research will prove to be a valuable tool. A great deal of development time can be saved by utilising such a system.