Search Results

A Torque converter is a type of hydro-mechanical device, vastly utilized in the automatic transmission of vehicles and other machines. It is a critical component of the transmission system, having a direct impact on the fuel economy and vehicle´s performance. Computational Fluid Dynamics (CFD) has been employed by many authors and engineers to better understand the complex behavior of fluids inside of torque converters, in a way that it provides design improvements and increases model accuracy. This article presents a methodology that applies CFD as a tool in the design process of automobile torque converters. Therefore, this paper performs an extensive review of CFD associated with torque converters, and the principal concepts are stated and used to have a better understanding of the system’s dynamic behavior. Additionally, this article details some of the work done to develop an automotive torque converter model using the commercial software ANSYS CFX.

Chassis dynamometers are important equipment to perform vehicular experiments in the automotive industry. Usually, these equipments are used according to standard procedures for emissions, fuel consumption, and performance analyses. In this paper, an alternative procedure was developed to experimentally determine the dynamometer inertia and losses related to bearings and transmission systems. Furthermore, a study on the tires rolling resistance, considering a double tire-roller contact, was carried out. The experiments were performed in a 4x2 chassis dynamometer with four rollers, equipped with an eddy current brake (coupled to a transmission reducer of 2.5 instrumented with a 3000 Nm torque flange) and with a 30 CV AC electric motor (coupled to a planetary transmission with reduction of 4.43 and instrumented with a 500 Nm torque flange). The dynamometer was also instrumented with an encoder system for speed measurement.

The need for improved fuel economy for road vehicles has increased the interest in hybrid electric vehicle (HEV) and recovering vehicle energy. This paper aims to evaluate the amount of kinetic energy that could be restored through regenerative braking in a HEV. This work will not resort the Brazilian urban driving cycle NBR 6601, for this cycle does not fully represent a pattern of traffic faced regularly in urban areas, which is typically composed of heavy traffic and long periods of idleness. Therefore, a new drive cycle will be developed that better represents the Brazilian traffic. Also, considering the shortage of energy resources, the large amount of energy dissipated as heat during braking a vehicle is a recurring concern. Therefore, measuring the maximum available energy that could be restored through regenerative braking is the first step towards estimating the profit of using this technology and how it would pay off the investment in the long run.

The development of hybrid vehicles has reached in recent years a high technical and commercial importance. In general, varied vehicular settings enable a motorization with several alternatives and conventional energies combined in order to increase the performance while reducing consumption and environmental impact. In the context of hybridization, particular attention has been given to vehicles that consider a secondary driving source of electric nature, mainly in countries where its cost is relatively low when compared with the cost of fossil fuels such as gasoline. This paper aims to achieve an economic and energy analysis of a hybridized vehicle. The last one has a conventional traction front-wheel driven by an internal combustion engine (ICE) and an electric traction rear-wheel propelled by electric motors (EMs) in-wheel.

The gear shifting strategies strongly influence the vehicle fuel consumption because they change the powertrain inertia and the engine operation point. The literature normally presents gear shifting strategies based on the engine power and torque to improve the vehicle acceleration performance. Strategies based on fuel economy are difficult to determine due to a large number of factors that influence the engine behavior such as the available transmission ratios, required acceleration and vehicle speed. In this paper it was evaluated the influence of the addition of more gear ratios in the vehicle gearbox, which initially contains five available gear ratios. For each proposed gearbox configuration, the gear shifting strategy was optimized through an algorithm developed to improve the engine fuel consumption in the Brazilian standard urban driving cycle NBR6601.

The search for better energy efficiency is leading the developments in automotive industry, looking for opportunities to reduce losses, optimizing the design and getting better efficiency of every component. This paper will present a non-linear dynamic study of interaction between commercial vehicle and the environment, considering all the influence of their dynamic characteristics in the fuel consumption. The first step is to analyze all variables that influence the dynamic behavior and then construct a mathematical model based on energy and based on forces (Newton). The interaction between the vehicle and its environment and the response of it will be considered as influent aspects and should be included into vehicle dynamic modeling.

Hybrid Electric Vehicles (HEVs) currently represent an alternative to reducing fossil fuel consumption used by internal combustion engines. This paper analyses, in a platform of computational simulation and also in experimental condition, the vehicle fuel consumption, before and after hybridization. It checks the similarity of behaviors and/or the investigation of possible differences between the developed mathematical model and experiments performed. Computer simulations help, through mathematical models, a better understanding of physical phenomena related to engineering problems. A well elaborated computer model has a high fidelity degree with the real systems, becoming a powerful analysis tool. The experiments besides allowing a proof of results, they contribute to a refinement of the simulated models. The hybrid technology under study is characterized by the coupling of two electric motors directly to the rear vehicle wheels.

The hybrid electric vehicle (HEVs) is an alternative to reduce the high dependence on petroleum products, because maintains the characteristics attributed to conventional vehicles such as performance, safety and trustworthiness and reduced the fuel consumption. Some modifications are necessary in the vehicle longitudinal dynamics equationing, to provide a specific power management control system, because of the electrical power source addition that complements the conventional engine and powertrain system. In this paper is used the HEV parallel configuration, where both drive systems are directly connected to the vehicle wheels, maintaining the engine/powertrain in the front wheels and electric motors directly coupled to the rear vehicle wheels.

The purpose of this paper is evaluating the amount of kinetic energy available to be regenerated by a hybrid electric vehicle (HEV) undergoing the Brazilian standardized driving cycle. Improvements on energy efficiency of the cars has become an urgent target of the Brazilian industry since Brazil launched a new automotive regulation imposing the reduction of 15.5% on the fuel consumption of the vehicles to be sold in this country in 2017 comparing to 2011. The HEVs are a possible solution for this situation. They are widely known by the high efficiency, mainly the ones capable to make the regenerative breaking, rescuing an already paid energy. Before the launch of HEVs in Brazil, the feasibility of these vehicles has to be accurately studied and one aspect to be evaluated is how much energy is possible to be rescued in the Brazilian standardized driving cycle.

One traditional solution to start an internal combustion engine is the starter motor. Little has been changed in its operational dynamics and conception, even after several design optimization processes. This fact stems from the absence of application of an analysis tool capable of showing the existing relations between its subgroups and the functions performed. But, once that these relations are explained and the basics functions are revealed, it is possible to generate a group of new technical solutions to perform the same functions. In order to achieve this goal, the present work applied a Morphological Analysis on the group of functions that is necessary and sufficient for a starter motor. The analysis of the Morphological Field revealed the nowadays trend of technical solutions and some solutions that hasn't been explored yet.

The automotive industry's recent push towards developing electric and hybrid electric vehicles is a direct response to the growing global pressure due to environmental concerns and has resulted in a search for significantly cleaner and more efficient vehicles. Not only, in order to achieve its purpose, has this search highly depended on the development of advanced technologies. Among all systems and subsystem from a vehicle the powertrain system is going to be the focus of this work. The main goal of the present work is to get a complete mapping of all the functions, components and flows of information and energy, through the application of an existing methodology of analysis, known for “function structure technique”, on the described product. Therefore, this mapping will supply a better understanding of the product architecture. First of all, the composed system, for the hybrid vehicle powertrain, is divided hierarchically in subsystems according to the existing assemblies.

This paper focus on the analysis of energy management for hybrid electric vehicles. The development of higher efficiency vehicles depends on the analysis of vehicle characteristics and driving conditions. Sizing the energy capacity of the storage system and defining the type of components, batteries or other kinds of electric components has a direct influence over the performance, consumption and autonomy of the vehicle. The forces involved in a vehicle movement such as aerodynamic drag, rolling resistance, grading resistance, are fully dependent on the conditions of the route; most situations should be represented on the driving pattern cycle, used for emissions and consumption tests, which will be presented and discussed. Modeling vehicle dynamic to analyze power and energy requirements of the vehicle during different test cycles provides an indication of the influence of hybrid technology in performance and fuel consumption.

Autonomous guided vehicles, called AGVs, are important components of factory automation and manufacture system integration that requires both technical and management skills. In this paper, an AGV prototype equipped with IR detectors and IR range sensors is programming to follow a route line on the floor and avoid some obstacles on the way. The motion of the experimental AGV is promote by two DC motor with build-in gearbox, working with simultaneous PWM control in closed-loop operation. This AGV is designed to operate in environments such as offices and shop floor, in order to carry light loads on flat surfaces and ramps with positive and negative inclination. Simulations tests with ADAMS® are compared with some experimental results in order to validate the model and the prototype approaches.

The design methodology have been proved its effectiveness concerned to new products development, and due to the systematic approach it allows great variety of solutions and concepts developed in the early concept design phase. This paper shows two efficient methods in concepts generation, they are: the brainstorm and the morphologic chart. Both were successfully used and the result was a new concept of wheelchair motorization which the electric motors are activated only when the force applied over the propulsion ring exceeds a preset value. This new concept was registered at INPI as an invention patent.

The design methodology have been proved its effectiveness concerned to new products development, and due to the systematic approach it allows great variety of solutions and concepts developed in the early concept design phase. Axiomatic design was use to create collaborative strategies aiming to reduce the number of control strategies tests. Besides only one of required functions was developed and test each time. A wheelchair dynamic model was developed to test the strategies. At the end of the processes a role and complex control strategy was developed and only validation tests were need to apply the solution in wheelchair motorization.

This study aims to evaluate the impact that changes in the parameters of the project to a continuously variable transmission has on its ability to transmit torque and power. A half-toroidal transmission is cinematically analyzed and key geometric parameters and their relationships are studied and characterized. A change in the parameters of the transmission geometry allows a verification of their influence on the entire system live-time for any type of cycle, as defined in the theory of life provided the causes of failure, fatigue and subsurface. Additionally is possible to evaluate the capability of transmitting torque through the theory of Elasto-Hydrodynamic (EHD) contact relationship and the range of possible transmission ratio to be achieved. In this paper, a geometric model of a traction based Half-toroidal CVT (see figure 1) were explored by adding new geometric parameters related to the system control mechanism (the roller tilting angle).

One traditional solution to start an internal combustion engine is the starter motor. Since its conception little was changed in its operational dynamics, even after passing by several design optimization processes. This fact elapses from the absence of application of an analysis tool capable to express the existing relations between its subgroups and the functions that these play. The main goal of the present work is to get a complete mapping of all the functions, components and flows of information and energy, through the application of an existing methodology of analysis, known for “function structure technique”, on the described product. Therefore, this mapping will supply a better understanding of the product architecture. First of all, the composed system for the starter motor is divided hierarchically in subsystems according to the existing assemblies. The operation chain is then separated through static and dynamic inspections during its use in the combustion engine.

The automated guided vehicles (AVGs) are normally used for the transport of materials, making great part in the manufacturing systems. This work aims at the study of the contact between ground and wheel in the AVG, thus applying the vehicle dynamics relative. For this, models of the contact between road and wheel had been made of AVG, in each model presents his considerations, simplifications and parameters as the cornering stiffness, the normal force and the sideslip. The models of the contact between road and wheel had been implemented in a multibodies program 2D and observed. The results of this work will be used in the construction of independent vehicles, because many AVGs don't take in consideration the dynamic behavior, they have a super dimension of engine so more weight and consumption of energy than they really need.

This work presents a study on the related basic aspects with the accelerated tests used in the industry to determine or to confirm the reliability of an item and of the methodologies currented to analysis of the accelerated tests of life of the products. Are argued the importance of the models for each distribution and the methodologies applied in the work.It is implemented programs of computation in VISUAL BASIC language that allow the management and the adequacy for the processing of the data proceeding from the accelerated tests with constant stress and simple failure mode, for complete data, and with censorship the right or multiple, using the distribution of Weibull, Log-normal and Normal, combined with the most used models (Arrhenius model and Inverse Power Law), the program allows to the processing of the data of the accelerated tests for two methods, Squared Minimums and Maximum Likelihood Principle.

Among manual wheelchair users has upper-extremity pain and injuries when self-propelling. However, manual propelling provides aerobic exercise. Powered wheelchairs are efficient to up/down ramps and long distance traveling, but it is heavy, bulky and the cost is very expensive. The ideal wheelchair system should have the advantages of both manual and powered wheelchairs. Therefore, it was developed the powered module for motorizing manual wheelchairs as a solution. This device is an intermediate alternative between manual and powered wheelchairs; it converts a manual wheelchair in a powered wheelchair. The module is a powered unit, which is attached, in all types of manual wheelchairs, quickly and easily by the user. It can be used for pushing or pulling the wheelchair in many environments. The purpose of this paper is to determine the dynamic behavior of the powered module-wheelchair.