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This work reports a conception phase of a piston engine global model. The model objective is forecast the motor performance (power, torque and specific consumption as a function of rotation and environmental conditions). Global model or Zero-dimensional is based on flux balance through each engine component. The resulting differential equations represents a compressive unsteady flow, in which, all dimensional variables are areas or volumes. A review is presented first. The ordinary differential equation system is presented and a Runge-Kutta method is proposed to solve it numerically. The model includes the momentum conservation equation to link the gas dynamics with the engine moving parts rigid body mechanics. As an oriented to objects model the documentation follows the UML standard. A discussion about the class diagrams is presented, relating the classes with physical model related. The OOP approach allows evolution from simple models to most complex ones without total code rewrite.

Fossil fuels and biofuels usage in internal combustion engines are the main source for vehicular propulsion. This justifies the intense worldwide research and development to comply with the challenges of increasing efficiency and emissions reduction. The modeling of commercial fuels and engine combustion processes presents great challenges. There is also the need to better understand how different fuel components interact and influence engine combustion and performance parameters. In previous works, components selection and engine dynamometer tests were done to identify representative surrogate fuels for commercial Brazilian gasoline. It was concluded that formulations with n-heptane, iso-octane, toluene and ethanol can be used to model oxygenated gasolines. Methodologies were implemented to evaluate the influence of the fuel components on fuel properties and several engine combustion and performance parameters.

This paper relates to the wind tunnel balance design that aims to meet the need for reliable but more affordable equipment that could accurately perform Aerodynamic measurements and act on three axes, being a Multitasking device, adaptable for prototypes of aircrafts, automobiles, buildings, sports products design, etc., through digital control that will measure the drag, lift and the aerodynamic pitch moment. The main task is stimulating creativity, to solve real problems and reduce technology dependence. The composite tubes used in the fixation of the "Sting-Compound" were chosen to avoid inaccurate measurements and have high flexural strength, even with a small cross section. That's feature is justified because the terminal velocity of wind tunnel is 50 m/s (97 knots), enabling to search many different model sizes and subsonic Reynolds speed regime.

To attend the new tendencies of the automotive market, new technologies must be used throughout the engine conception. One way of improving the project is to use computational numerical simulation, predicting engine behavior in a wide range of situations. This paper presents a methodology to estimate the engine characteristic parameters necessary to numerical simulation. Morse test was used to determine friction power, mean effective pressure friction and friction torque, considering the engine behavior during cylinder ignition cut-off. In this test all the results were compatible with manufacturer data, which validates the methodology. To define the moment of inertia, it's also proposed a fuel cut methodology, associated with the Morse test, because the torque values measured by dynamometer after the fuel cut did not correspond to the real value. Thus, plausible values of engine moment of inertia, very close to values obtained by software, were obtained.

An experimental investigation was performed on an engine dynamometer to study in cylinder pressure curve and combustion parameters variability with ethanol addition. It was used a Flex-Fuel engine, 1.4 L, 4 cylinders, with a programmable engine control unit to optimize the calibration for different blends of Brazilian gasoline and hydrous ethanol. Engine was calibrated for maximum break torque limited by knocking. In-cylinder pressure was measured by using a pressure sensor installed on the spark plug and analyzed by a combustion data system. Combustion duration, mass fraction burned, indicated mean effective pressure (IMEP) and others were calculated based on in-cylinder pressure curve data. The combustion variability was analyzed from 300 recorded engine cycle for each operating condition. Results for some operating conditions indicated that ethanol addition can reduce combustion variability on a non linear pattern.

Nowadays computer simulation is an important tool to support new internal combustion engine projects, but still further studies are necessary for its use in fuel development. In order to study the influence of fuel properties on engine combustion and emission performance, a computer model was designed based on a Flex-Fuel engine geometric data. Model was validated with experimental tests done on an engine dynamometer. A simulation software was used to simulate the experimental conditions, by using Wiebe two zone combustion and Woschni heat transfer models. In-cylinder maximum pressure, IMEP and emission data were calculated for different gasoline-hydrous ethanol blends at 3875 rpm, 60 Nm and 105 Nm. Total hydrocarbons concentration was simulated comparing the experimental data of hydrocarbons added with unburned ethanol emission measured with a FTIR analyzer.

In this work an algebraic model for the thermodynamic study of the compression-ignition engine is developed using the concept of efficiencies in the processes that compose the air standard cycle. In this model, the use of the efficiency concept added to the variation of the specific heat, the heat release based on Wiebe function, and variation of the initial instant of heat release and heat rejection, makes this no ideal cycle to approach the actual Diesel operation. A cinematic model of the crank-and-connecting rod mechanism is used to transform the gas work in axis torque. This model serves as didactic tool for the thermodynamic analysis of the compression-ignition engines operation.

The new trends of the automotive market require the application of new technologies to a concept of engines, which allows for the use of different types of fuel. The multi-fuel engines available in the market display only one compression ratio, therefore being subject to optimization, as to obtain maximum efficiency the engine must work with a variable compression ratio. Although technically possible, this procedure is not considered feasible for a low-cost product. This work proposes a system, which allows for each type of fuel to attain peak efficiency through a variance in the engine intake pressure and without changing its compression ratio, a feature that can be added to a low-cost product. The gains obtained with this project will be shown in each stage of the experiment and compared to those of the original configuration of the engine. The methodology to be used is the DOE - Design of Experiment.

In order to utilize exhaust gas energy effectively, various engine systems equipped with turbochargers have been proposed based in matching techniques. The matching between internal combustion engines and turbochargers depends on the previous knowledge of flow maps of turbine and compressor. This work presents a radial turbocharger model based in modified Euler equation. This equation was obtained through mass, energy and moment balances for turbine and compressor, considering an adiabatic ideal gas model with polytropics compression and expansion and using thermodynamics properties of stagnation. The Euler equation allows determination of the operation points of the system engine-turbocharger through the knowledge of the thermodynamics properties of exhaustion gases and geometrical characteristics of turbocharger. It still allows the attainment of flow maps of compressors and turbines.

This work is about design of a static test stand for aeronautical engines with propeller. The objective is measure propeller thrust and engine torque (two degree of freedom). The design covers system specifications, structural design, dynamic analysis, instrumentation project and tests and calibration procedures. It specifies maximum forces to be measured, maximum propeller diameter and types of tests, as constant rotation, acceleration and robustness. Also, it is presented design recommendations covering structural loads, joint types, engine accessories and minimum instrumentation. A stand sketch is showed and calibration procedures were discussed. To forecast the system resonance frequency and dynamic behavior, plots of stand-sensors system dynamic response were presented. This test stand allows measuring propeller static efficiency and engine-propeller system static propulsive curve.

Gasoline is composed of hundreds of components. The fuel properties can present a wide range of variation, depending on the formulation. Commercial fuel specifications differ from country to country, based on the features of each market. Also, fuels for some specific engine applications can differ widely from commercial fuels. For the next decades it is expected that the fossil fuels and bio-fuels usage in internal combustion engines remains to be the main source for vehicular propulsion. This justifies the intense worldwide research and development to comply with the challenges of increasing efficiency and emissions reduction. In this context the fuel can play an important role, mainly when there is the possibility to optimize fuel formulation, engine design and engine calibration for the desired application.

Atomization parameters from the spray produced by a direct injection injector, operating into an engine with optical access were analyzed in this work. Parameters such as cone angle, penetration and spray geometry for determined crank angles and different rotations, with the respective variability, were evaluated for ethanol injection. Images from spray injection were captured for the specified rotation conditions for the angle and geometry analysis. For the penetration analysis, the image acquisition occurred with crank angle variation, obtaining a mean value with respect to the spray displacement of a point of maximum concentration on a specified direction. Lines were adjusted to the penetration data and the penetration rates (velocities) were evaluated through its slopes. For the cone angle and geometry study, an automatic routine in Matlab environment for image processing was used.

One-dimensional models for internal combustion engines analysis are very useful to simulate its systems through a relatively low computational effort. Based on this idea, this paper presents the simulation of a spark-ignition engine using one-dimensional models implemented in object oriented programming by the authors. The model was adapted to simulate a research four valves, single cylinder, spark ignition, reciprocating internal combustion engine. The gas in the cylinder was described by conservation equations, including the momentum conservation equation, that wasn’t found in the checked literature. For the combustion, a two zones model was implemented, based on combustion wave equations, such that detonation and deflagration are calculated by the same set of equations. The flame propagation geometry was considered to be spherical.