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This work presents the experimental determination of an automotive turbocharger flow map, by using a flux test stand. This equipment is able to reproduce and measure the main characteristics of an intake and exhaust flows of an automotive engine. To build the compressor and turbine flow maps, the experimental data should be treated through an empirical model. Flow maps of two turbochargers are presented. The first flow map presented was used to validate the data treating method. The validation process made use of published GT12 Garrett turbocharger data. The data treating method was applied on the experimental dada of T2 Garrett turbocharger obtained on the flux test stand. The flow maps build are shown, and operational limits are identified on then. These flow maps give essential information to choose the most suitable turbocharger for a specific internal combustion engine.

In this paper, computational fluid dynamics (CFD) were employed to a qualitatively and quantitatively study in the behavior of the cold flow in a turbocharged three cylinder spark ignition engine. Dynamic flow experimental characterization was made for low and high engine rotation. One-dimensional modeling software GT-Power was used to calculate the flow pattern generated within the engine cylinder and the results were used as boundary and initialization condition in the CFD model. From the results of the commercial code, volumetric efficiency, in-cylinder pressure and mass are calculated for evaluating the flow development through the four engine strokes, during 4 complete cycles. The CFD model was used as a less expensive alternative to make a deeper study of the flow field.

Extensive studies of pre-chamber ignition systems in internal combustion engines have proven its effectiveness in reduction of fuel consumption and improvement in several combustion parameters. Considering the different types of pre-chamber configurations, this paper aims to compare the combustion in a SI engine with both homogeneous and stratified pre-chamber ignition systems. To achieve this objective a system with the ability to control the hydrogen injection in the pre-chamber was built. This system was installed in a multi-cylinder Ford Sigma 1.6L engine and tested in a dynamometric room. Tests consisted in imposing a constant rotation and IMEP to test three conditions: standard spark ignition, pre-chamber ignition system without fuel injection (homogenous) and with hydrogen injection (stratified). It was possible to identify that with the use of pre-chamber ignition system there is a reduction in specific fuel consumption and in the combustion duration.

Environmental policies and fuel costs have driven the development of new technologies for internal combustion engines. In this sense, the use of mixtures with small portions of fuel allows lower fuel consumption and pollutants emissions, emerging as a promising strategy. Despite the advantages, lean burn requires a larger energy source to provide satisfactory flame propagation speed and consequently a stable combustion. The use of pre-chamber ignition systems (PCIS) has been used in SI engines to assist the start of combustion of lean mixtures, in which a supplementary fuel system can stratify the amount of either liquid or gaseous fuels supplied to the pre-chamber. In this context, this paper aims to evaluate combustion characteristics of a commercial engine with the use of stratified PCIS operating with impoverished mixtures of ethanol-air in main-chamber and hydrogen assistance in pre-chamber.

Due to the large negative impact of combustion gas emissions on air quality and the more stringent environmental legislation, research on internal combustion engines (ICE) are being developed to reduce emissions of pollutant gases to the atmosphere. One of the research fronts is the use of lean mixtures with the pre-chamber ignition system (PCIS). This system consists of a pre-chamber (PC) connected to the main chamber by one or more interconnecting holes. A spark plug initiates combustion of the mixture present in the pre-chamber, which is propagated as gas jet into the main chamber, igniting the lean mixture present therein. The gas jets have high thermal and kinetic energy, which promote faster combustion duration, making the system less prone to knock and with lower cyclic variability of the IMEP, enabling the lean limit extension. The pre-chamber system can be assisted with a supplementary liquid or gaseous fuel injection, enabling the charge stratification.

The design and development of highly efficient internal combustion engines require a thorough investigation of the fluid dynamic processes. This paper presents the experimentally determination and computational fluid dynamics simulations of the intake valves discharge coefficients of a four valve spark-ignition single cylinder research engine. The mass flow rate and air pressure were measured directly in the intake port for six different values of valve lift (4.68; 6.16; 7.48; 8.62; 9.46; and 10.49mm). The theoretical mass flow rates were obtained based on considerations of subsonic flow. Simulations were carried using the Star CCM+ commercial code. Mesh independence studies, using the velocity fields as monitors, have been made for reliability of the simulations. As a result, a methodology was successfully implemented to obtain the discharge coefficients experimentally and the simulations were validated with a maximum deviation of 6.62%.

Direct inject engine provides increased possibilities to work with injection strategies in order to achieve better efficiency. Some ethanol properties such as the higher octane number, the latent heat of vaporization as well as the faster laminar speed made ethanol one of the most promising biofuels. These properties help to achieve knock suppression in a SI engine and therefore allow the use of higher volumetric compression ratio, which is one of the key factors in efficiency improvement. Several studies have showed ethanol as a way to reduce soot formation in direct injection engines as the oxygen molecule reduces the locally fuel-rich region. The use of ethanol contributes significantly to the reduction of total hydrocarbon (THC) and carbon monoxide (CO).

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.

Trends of the automotive market require the application of new engine technologies, which allows for the use of different types of fuel. Currently available multi-fuel engines operate with constant compression ratio irrespective to the fuel being used, however for best performance the engine should work with a variable compression ratio. Although technically possible, this is not considered feasible for a low-cost product. In order to circumvent this and other losses, it was devised an innovative approach, which adopts turbocharging to allow optimum performance for different fuels, without changing compression ratio, an advance that can be added to low cost products. Alternatively, this approach can be used as an optimization tool along more conventional engines development. This advance will be implemented into a 1.3 8v FIRE FLEX MULTI-FUEL engine capable of operating with Gasoline E25, E94 ethyl hydrate, any blend of Gasoline E25 and Alcohol E94, and natural gas.

This work presents an experimental procedure to find the best operating point for a spark ignition engine controlled by a general Engine Management System. The ECU control allows changing the ignition and fuel injection timing as a function of load and rotational speed, beyond configuring the whole system according to the sensors and actuators types. The ignition dwell time and the best moment to start the injection fuel can be controlled accurately by this system. In addition, this electronic system allows adjustments in real time with engine installed onto a dynamometric test stand. This work describes the experimental apparatus, sensors characteristics used and also the methodology to accomplish the adjustments in the ECU maps, seeking to obtain the best performance. Comparison performance data for the standard engine and the proposed configuration are presented here, showing a 50% gain for a spark ignition engine of 1300 cm3, four cylinders in line, and 16 valves.

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.

The use of torch ignition systems in spark-ignition engines represents an interesting option in the efforts to reduce pollutants emission and specific fuel consumption. Based on this idea, this paper presents a 3D model of a prechamber created for a spark-ignition engine and focuses on the numerical analysis of the fluid flow inside the modified chamber. This kind of analysis is very important once it allowed evaluating aspects like turbulence parameters, pressure inside the chamber and prechamber, fluid recirculation and a possible prechamber’s geometry for the engine. The studies were done in a four valve Single Cylinder Research Engine - SCRE. For the numerical modeling and fluid flow investigation it was used STAR-CD Software. The numerical results permitted to characterize the fluid flow in the modified engine and compare it with the standard engine, which showed significant differences and an interesting potential.

The new trends of the automotive market require the development of a new concept of engines using different types of fuel, mainly those resulting from alternative sources of energy. For this purpose those multi-fuel engines must function with higher energy efficiency therefore allowing for lower fuel consumption and a drastic reduction of exhaust emission. The multi-fuel engines available in the market display only one volumetric compression ratio, which leaves ample room for the development of a better level of fuel energy use. To achieve so, such an engine must count on a variable volumetric compression ratio, which, despite being technically possible, is not economically viable for a low cost product. The present project intends to create a system capable of achieving the best performance for all types of fuel through the variation of the boost pressure, viable for a low cost product, without changing its volumetric compression ratio.

The purpose of this work is to present an experimental methodology to characterize the in-cylinder tumbling flow generated by a motored four-valve spark ignition single cylinder optical research engine. High-speed two-dimensional particle image velocimetry measurements were made in the symmetry vertical plane between the inlet and outlet valves. The velocity flow fields were recorded during the intake and compression strokes for three different engine speeds (1000, 1500 and 2000 rpm) at several crank angles. Vorticity, tumble ratio and kinetic energy were calculated and compared. Also, an evolution analysis of the main vortex center was made. As result, the tumble ratio and kinetic energy showed a decrease at the end of intake stroke. Flow field cyclic variation could be noticed. The methodology contributes to a better understanding of flow motion behavior, and consequently, the mixture formation process in spark ignition engines.

The technological development of automotive engines is focused on alternative energy sources and optimized use of conventional fuels. The current flexible engines in Brazil can operate with gasohol and ethanol blends in any proportion, but the flexibility is restricted to liquid fuels. The present investigation consists on the use of electronic injection systems for ethanol and for CNG, allowing the use of these fuels simultaneously. The objective of this work is to determine the best proportion of CNG-ethanol mixture in order to maximize the use of the natural gas, fuel which offers the lowest BSFC on conventional SI engines. The low volumetric efficiency inherent in the use of CNG is compensated by the injection of a small quantity of ethanol. The latent heat of vaporization of the alcohol is used to take heat from the intake air and increase its mass, taking advantage from the high latent heat of vaporization of the ethanol and the low BSFC of the CNG.

In this work is proposed the installation of a turbocharger in a low dislocated volume engine, aiming to achieve a higher effective mean pressure and air fuel mixture density, for a better performance of the converted engine. This analysis is made through experimental tests in a break bench, following the Brazilian standard NBR ISO 1585. The results presented shows the basic behavior of the torque curves, power and gas emission, which reflects the changes in performance with both fuels for a aspirated and turbocharged engine, for all the engine rotation speeds. These results show the technical and economical viability of the conversion to Vehicular Natural Gas of a low cc engine, when adapted a commercial turbocharger kit.

In this work an analysis of the performance of a multi-fuel engine fuelled allowing for the concentration of alcohol in gasoline and the use of CNG. The engine used was a four cylinder, 1.242-L, multi-fuel engine in full load, respecting the air/fuel rate established by the manufactures in the engine original calibration. A CNG BRC 5th generation multi-point fuel injection system was installed in order to run with CNG. The calibration and adjustments were made using a development engine control unit for the different fuels. This work presents a comparison among the performance curves aiming to obtain the best relation among torque, power and specific fuel consumption for the various proposed configurations.

The analysis of the air motion inside the cylinders of an internal combustion engine constitutes a very important step during engines design. It is already known that its movement, normally decomposed in tumble and swirl motion, is totally related to the majority of phenomena which occur inside cylinder, like fuel evaporation, mixture formation or flame propagation. The use of mechanical devices in the intake system represents an interesting option in the attempt of optimizing the airflow and finding the best condition for maximum power and minimum specific fuel consumption. Devices like flow boxes, which control the airflow and change its main characteristics before entering the cylinder, by obstructing the air and changing its directions, are one possibility. Based on this idea, this paper presents a numerical analysis of the utilization of a flow box in the intake system of a spark ignition engine.

This paper presents the adjustment of an extended coherent flame model - three zones (ECFM-3Z) by the analysis of its variables α and β for application in a 3D computational fluid dynamics (CFD) model of a two valve engine fueled with ethanol. The engine is aspirated and uses direct injection of ethanol as a single injection. High frequency pressure gauges are used at the cylinder, intake and exhaust manifolds in order to perform a three pressure analysis (TPA) and this data were used as boundary conditions for the CFD model. In the tests the engine speed varied in the range of 1500 to 4000 rpm, and throttle position in the range of 20% to 100% (WOT), although wide open throttle (WOT) was used for adjustment of the combustion model parameters. The computational model uses the ES-ICE module of PROSTAR for moving mesh generation, implementation of boundary conditions and transient analysis of global variables.