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The clutch actuation system has the function of convert force made by the user on the pedal to a force acting on the clutch fingers. This system is compound with many components and one of than is the clutch release bearing. The clutch release bearing has direct contact with the finger of the clutch and materials in contact suffer a relative motion. In some case this relative motion is desired and other undesired. Thus this contact surface and the relative motion are important parameters to correct operation and to avoid wear. This paper will study the contact mechanic of this system and for this a large bibliographical review will be made and rise. Basic models and simulations will be developed to visualize the behavior of this system and also some experimental test will be done with different contact surface. This work will help to better understand the contact behavior and design contact geometry for minimum wear.

Vehicular emissions limits have been reduced throughout the world in compliance with environmental legislations. With the rapid increase in the number of flex-fuel vehicles on the market, the consumption of ethanol has also increased. As a result, there is expected to be a large abundance of unburned alcohol from tailpipe gas emissions. Another important factor arising from the use of ethanol is the formation of tropospheric ozone. The objective of this study was to measure the amount of unburned alcohol and legislated emissions as well as the ozone formation potential of a passenger (light-duty) vehicle fueled with gasoline containing different concentrations of ethanol. The main conclusion is that unburned alcohol emissions increase in direct proportion to the ethanol content in the fuel. The unburned alcohol was measured by two techniques: gas chromatography and FTIR.

In order to have a windshield wiper system according to wiped area and kinematic behavior requirements since the early phases of vehicle development, this paper makes use of a MATLAB optimization function to optimize the windshield wiper system. The main goal is to achieve the maximum wiped area by optimizing wiper blades lengths and orientations. Parallel to that, constrains make the method finds the optimum kinematic design for the windshield wiper linkage in terms of mobility, available area to fix the linkage on body and the maximum range of the blades oscillatory motion. This optimization is applied on an existent windshield wiper system of a domestic passenger car to present the benefits of the developed model.

Nowadays, due to the global warming questions related to CO2 emissions, many countries legislation lead automotive and fuel industries to search for higher efficiencies in their products. Therefore, new engine technologies and cleaner fuels are being developed and launched in the market. This paper presents a study of efficiencies on chassis dynamometer tests, in order to evaluate vehicle and fuel contributions. Tests were performed using one Brazilian flex fuel vehicle in full load condition at constant speeds to evaluate the losses of each part of the system, such as, wheel, air resistance and powertrain. The vehicle energy parcels were determined. So, it was possible to assess vehicles mechanical losses, aerodynamic losses and also the engine efficiencies.

The detailed study of cosmic ray's influence is recent, as well as the invention of the transistor. Ionizing particles from space that focus on silicon integrated circuits (IC) can cause many undesirable effects. These particles are mainly from solar activity, and can be classified into two basic groups: charged particles, e.g, electrons, protons or heavy ions, and electromagnetic radiation (photons), as X-rays, Gamma -rays, or Ultraviolet (UV) light. When they collide in an IC, these energetic particles cause a current pulse, which can affect the correct functioning of the device. These electronic circuits have become increasingly susceptible to the effects of radiation, due to miniaturization, thus increasing the incidence of failures.

Changes in the macro economic scenario of Brazil during the latest 10 years resulted on several changes in the auto industry market. One, which affected important requirements of the light duty trucks, regards the migration of customers from passenger car segments to light duty pickups. A considerable portion of these new pick-up customers expects an overall level of comfort, handling, noise and vibration similar to the levels found in passenger cars. One possible conclusion of this trend is that an optimized vehicle system integration is vital to prevent potential issues and to assure the achievement of customer satisfaction. Among several vehicle systems, the Drivetrain integration deserves the major attention. This paper shares lessons learned on the integration of the manual Transmission, external shifter, mountings, propeller shaft, rear axle and suspension with the rest of the vehicle.

Nowadays, the influence of aerodynamics on vehicles capabilities is mostly studied in terms of energy efficiency; maximum speed; maximum linear accelerations; cooling capacity of brake systems; resistance and deformation of elements exposed to aerodynamic forces; stability during lateral wind and during braking for straight ahead maneuvers; noise caused by airflow; proper evacuation of exhaust gases and aesthetics of cars. Generally, a model for CFD analysis is used and six constant coefficients are determined. However, there is insufficient information about the interaction of vehicle aerodynamics with vehicle suspension and the effects that this interaction generates on the dynamic behavior of the vehicle. In this work this interaction is studied, and there is an analysis of how vehicle aerodynamic characteristics impact on suspension behavior and how suspension characteristics could diminish or amplify aerodynamic.

Stringent automotive emissions and fuel economy regulations have been bringing challenges for the development of new engine technologies to achieve greater levels of efficiency and pollutants reduction. In this scenario the homogeneous charge pre-chamber jet ignition system (HCJI) enables lean operation due the jet combustion gases emerging from the small pre-chamber combustor as the ignition source for main chamber combustion in an internal combustion engine. The present computational work was carrying out to investigate the interaction between the pre-chamber and main chamber fluid dynamics events. This CFD research was performed and validated with a experimental data for a single cylinder of a 4-stroke indirect fuel injection engine under the motoring condition running at 4500 rpm with 50% wide open throttle condition.

The objective of this article is to present a root-cause analysis performed to support the fault trace of a heavy duty diesel engine breakdown, operating in high altitude. The process to elaborate a cause-effect diagram, also known as Ishikawa diagram is briefly described. Some factors that can influence the engine behavior and its reliability are listed in the cause-effect diagram. According to the failure mode analyzed, the selected factors are then described, and how they could interfere in the engine functioning.

Fulfill emission restrictions is the most challenging task of future engines development. In this context, improvements with regard to the spray and mixture formation in internal combustion engines are necessary. Experimental investigation and numerical simulation have been used to predict and analyze complex in cylinder processes. In this paper, a diesel spray characterization using optical diagnostics was made in order to provide input data and boundary conditions for a diesel spray computational fluid dynamics simulation (CFD), using the Eulerian-Lagrangian model. Combining the advantages of Eulerian and Lagrangian approaches, this model is able to predict continuously the whole spray evolution. The main difficulty of numerical spray simulation is the correct representation of the two characteristic spray zones: dense near the nozzle and dilute downstream.

This paper presents a thermal analysis of a sub-set drum/shoe brake lining of a braking system in a rear drum brake for a lightweight passenger vehicle with engines of up to 1,000 cc, for a future application to hybrid power trains. In academic databases, as well as free research database, it is difficult to find papers and even technical works which show the complete cycle of the design of an automotive braking system. It occurs mostly due to the confidentiality of industries and industrial parts suppliers, once the brake system is a product of high added value. In this study, transient temperature field distributions of the shoe lining were obtained by numerical simulations. Boundary conditions of the model were calculated according to a reference paper. The geometry and mechanical and thermal properties of the brake shoe lining were obtained from data provided by the manufacturer.

Some chemical characteristics and natural impurities of diesel fuel used in diesel engines may damage the operation of emission control devices as well as contribute to the formation of secondary pollutants in the atmosphere. Sulfur is one of the natural impurities of diesel fuel, which upon burning, combines with oxygen to form SO2, creating emissions that adversely affect both the environment and human health. Many countries around the world have adopted stringent diesel emission standards to drastically reduce the sulfur content in diesel fuel and thereby improve air quality. Many authors have addressed the need to regulate transportation fuel emissions from pollutants, including sulfur (S), carbon monoxide (CO), particulate matter (PM), nitrogen oxides (NOx) and hydrocarbons (HC). This paper addresses both regulated and non-regulated emissions from four types of diesel fuels, each with a different sulfur concentration.

The clutch pedal is one of the most used commands on vehicles and demands a robust project, good ergonomics and an adequate feeling. According to Shaver [3], a comfortable clutch pedal should have a load between 10 kgf and 13 kgf, but the total stroke, the maintenance of the load during the travel, peak load, etc. still has to be considered in the project. Basically the suggested curve for a comfortable clutch pedal starts with a progressive increase load until approximately ¼ of the stroke, and after a decreasing load until the pedal reaches its stroke limits. This effect can be produced through an auxiliary spring that ranges its force direction according to the position of the pedal. This article presents a methodology of modeling an auxiliary spring for clutch pedals and its installation geometry on the pedal box to achieve an adequate pedal feel. This theory is applied to semi-hydraulic and hydraulic systems clutches.

The purpose of this paper is to provide an overview about rowing clunk on RWD MT transmissions for pick-up trucks through means of sound pressure, case acceleration and torsional vibration. Intended to identify the proper synchronizer design features necessary for its prevention. This paper will introduce the rowing clunk phenomena and present the driving maneuvers executed to reproduce the noise. The process of analysis and the phenomena composition based on simulations results, noise measurements and vibration analysis. The objective is to share with Product Engineering community an approach for Rowing Clunk Noise mitigation on Pick-up Trucks.

A vehicle is a product that encloses high levels of complexity. Assessing its quality requires taking into account several variables simultaneously. Usually, this kind of analysis is made over one variable at a time, ignoring the multidimensional nature of the quality. This is even more critical when two or more vehicles are included in the analysis (e.g. for benchmarking purposes), or when the aim of the analysis is to evaluate the performance of more than one variable over time. This study presents an overview of the biplot, which is a low-dimensional representation of observations and variables, and the possibility to use it in monitoring multiple quality variables. We show a case study demonstrating that Principal Components Analysis (PCA) allows us to summarize in a two-dimensional biplot the information that would require a correlation matrix, several conventional plots and further analysis when comparing eight variables measured on two vehicles over the last four years.

This paper discusses the behavior of kinetic friction coefficient and temperature on contact of Polytetrafluoroethylene (PTFE) in a dry sliding test against stainless steel. This polymer is widely used in industry for many tribological applications without lubrication. It was performed essential tribological evaluations: the overall shape analysis of kinetic friction coefficient and temperature on contact curves, regions identification with distinct behavior and the mean and the standard deviation of the values obtained. For this purpose, long duration tests were performed (120 minutes) in a kinetic friction machine, developed and built at the UTFPR's Laboratory of Contact Surfaces, in which a PTFE plain bearing slides without lubrication over a stainless steel shaft with monitoring of kinetic friction coefficient and temperature on contact. The test condition simulates the polymer real application as plain bearing.

The increase in crash tests done for independent entities of consumer protection, such as the Euro NCAP (Europe) or IIHS (United States) have shown increasingly importance for safety regarding the occupant protection. The consumer of the automotive market in developed countries, as United States or countries of European Union for example, they seek for a safer vehicle when buying a new one. On the other hand in Brazil, the consumer does not have the culture of buying a vehicle thinking in safety performance, but they choose the cars because of body style and accessories. The regulation of the Brazilian government's obligation to Air Bag and ABS brakes for all vehicles produced in the country from January 2014 and the INOVAR AUTO program, aims to bring more safety to vehicles produced in the country.

This paper describes the strategy of lubricant oil service interval for commercial truck based on new engine technology (PROCONVE P7), the fleet owner's needs, vehicle typical application route, operational costs related to oil change, design of oil pan to adequate the oil volume and lubricant oil available technology. In result, this analysis shows the best annual operational cost for customer in terms of oil change.

To reduce atmospheric CO2 emissions as well as crude oil consumption, several countries have started to increase the ethanol content in gasoline. Brazil is unique in this respect, where pure ethanol fuel (E100) is offered on the market, however the use of pure ethanol as a fuel, significantly affects engine oil dilution. High oil dilution directly affects the injection system, during the fuel evaporation process. The evaporation behaviour is mainly characterized by the chemical composition of the fuel accumulated in the oil, as well as the engine warm-up behaviour. A high proportion of the accumulated hydrocarbons in the engine oil evaporates, as engine oil temperature increases. There can be dramatic effects on systems that are not designed to consider the evaporated hydrocarbons. Effects such as misfire or engine stall are well known phenomena of unconsidered fuel evaporation.

It is increasingly urgent to define a technology that allows the replacement current vehicles powered by internal combustion engines by a more sustainable vehicle. There are several technological options such as electric vehicles, hybrids and vehicles powered by biofuels. So far there is no clear methodology for comparing the strengths and weaknesses of these alternative technologies. This paper presents a methodology that aims to compare from a strategic point of view technological alternatives comprehensively prioritizing their impacts throughout the lifecycle thus providing a clearer basis for decision making.