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Significant efforts have been made in internal combustion engine development to meet the most restrictive emission regulations. Analysis of in-cylinder pressure-time history is one of the most powerful tools to address combustion chamber design and engine calibration. This analysis provides information about load, knock occurrence and intensity, combustion phasing, combustion duration, shape of heat release rate curve and mass fraction burned. Aiming at an efficient real-time monitoring of combustion and engine performance, a processing framework was proposed. The proposed framework seeks to balance parameters accuracy with computational cost. For this, the number of points used on each parameter calculation is reduced by splitting the processing into two paths of data detailing and partitioning. Also, to reduce additional expenses with supplementary hardware, thermodynamics methods were applied to use only the in-cylinder pressure data.

Low Temperature Combustion (LTC) is an emerging technology that offers an alternative to conventional spark and compression ignition. A highly discussed LTC mode is homogeneous charge compression ignition (HCCI), which consists in a combustion of a highly diluted well-mixed charge at the end of compression stroke, when the charge reaches the auto-ignition state. Since HCCI is an LTC mode, it can result in low NOX emissions with an indicated efficiency comparable to a diesel engine. Otherwise, there are some challenges to overcome such as achieving high loads without knocking and combustion timing control. Several methods to control the combustion had been investigated, between them, the injection of water may be useful to extend HCCI knock free operation and to enable combustion phasing control. This work investigated the influence of water injection in the intake of an ethanol HCCI cylinder from a converted diesel generator set.

The forecast scenarios regarding the environmental pollution raises a question whether the current vehicle emission certification is reliable enough to assure fleet agreement with the legal limits. Type approval tests have been performed on chassis dynamometer in order to evaluate the emission factors and fuel consumption for passenger cars. Standardized procedures such as the FTP-75 proposed in the United States (currently incorporated in the Brazilian legislation) and the Worldwide harmonized Light vehicles Test Cycle (WLTC), a transient driving cycle model designed by the European Union to overcome the shortcomings of the New European Driving Cycle (NEDC), are discussed in this paper. Both cycles were performed in a chassis dynamometer with a flex-fuel passenger car running on ethanol blend (E92W08). The driver, vehicle and fuel were kept constant so the comparison between the cycles would not be compromised.

This work compares the accuracy of in-cylinder pressure and apparent heat release rate (AHRR) diagrams to the experimental data and the use of different chemical kinetics models applied to the GT-Power® software. The engine computational model is based on a naturally aspirated diesel engine with three cylinders, one of them modified to operate with hydrous ethanol with port fuel injection and HCCI combustion achieved with hot exhaust gas recirculation (EGR) of the Diesel cylinders. Operating points chosen to perform the comparison to experimental tests were 1800 rpm, 300 kPa of indicated mean effective pressure and fuels with 10% and 20% of water-in-ethanol by volume. The kinetic mechanisms for ethanol oxidation evaluated were the detailed NUI Galway and a Skeletal model based on it. With either model, cylinder pressure diagrams were not very different from the experimental values. The detailed mechanism was, on average, 9 times slower to process each case than the Skeletal mechanism.

Exhaust silencer design in motorsport is a matter of establishing the best compromise between rules compliance, mass savings and engine restriction. A design methodology that acknowledges these difficulties is likely to be desirable to ensure that the best solution is always provided for the competing team. The present work takes into account a comprehensive analysis of mass versus silencer restriction matter, based on simulated lap times to find the optimal compromises. A thorough discussion concerning the different techniques concerning passive noise control is held, establishing a widely comprehensive concept study phase. Further optimisation of the best concept is conducted via Design of Experiments. A final finite element analysis is conducted in order to assess the quality of the proposed solution across a larger range of frequencies and confirm the design formulated so far as effective.

Using Exhaust Gas Recycling (EGR) on internal combustion engines enables the reduction of emissions with a low or even no cost to the engine efficiency at part-load operation. The charge dilution with EGR can even increase the engine efficiency due to de-throttling and reduction of part load pumping losses. This experimental study proposed the use of late exhaust valve closure (LEVC) to achieve internal EGR (increased residual gas trapping). A naturally aspirated single cylinder direct injection spark ignition engine equipped with four electro-hydraulic actuated valves that enabled full valve timing and lift variation. Eight levels of positive valve overlap (PVO) with LEVC were used at the constant load of 6.0 bar IMEP and the speed of 1500 rpm. The results have shown that later exhaust valve closure (EVC) required greater intake pressures to maintain the engine load due to the higher burned gases content. Hence, lower pumping losses and thus higher indicated efficiency were obtained.

Among the gases usually emitted by internal combustion engines, NOx chemical species appear as some of the causes of great environmental impact and damage to human health, which shows the relevance of its study and quantification, as well as the constant search for the reduction of these emissions. The use of biofuels such as hydrous ethanol and n-butanol has the goal of reducing CO2 emissions in comparison to fossil fuels. However, it has to be accomplished without increasing NOx emissions. Analyzing combustion of these two fuels through a two-zone model for an Otto cycle engine, this work compared quantitatively the NOx emissions with the Zeldovich reaction mechanism, which can predict the formation and consumption of these chemical species during the engine's combustion cycle, being thus known as thermal NO.

The ethanol fuel sold in Brazil, which is seen as an option that represents less polluting gases emitted into the atmosphere, goes through a period where its economic viability does not compensate its use against the alternative coming from nonrenewable sources. It is known that part of the cost associated with commercial ethanol is due to its purification through distillation, which decreases the water percentage in the final composition. Aiming to evaluate alternatives to reduce the final cost of the fuel, a comparison was made between the burning results of hydrous ethanol, with up to 5% of water by volume, and the wet ethanol, with 30% water by volume, in an Otto cycle engine, operating with a fixed speed of 1800 RPM and seeking the maximum brake torque in each test.

Global warming and pollutant emission concerns have been driving research towards cleaner and environmentally friendly fuels. Like ethanol, butanol is a promising biofuel with characteristics such as higher calorific value and lower latent heat of vaporization. Due to its similar properties to those of gasoline, butanol stands as a potential gasoline surrogate. Butanol can be produced from through the ABE (acetone–butanol–ethanol) fermentation process, which uses bacterial fermentation to produce acetone, n-Butanol, and ethanol from carbohydrates such as starch and glucose. This work presents the experimental results of a single-cylinder spark ignition research engine equipped with port fuel injection. Several compression ratios were compared via spacer rings. Fuels as n-butanol, hydrous ethanol (E95W05) and their blends were evaluated in comparison to primary reverence fuel (isooctane).

Vegetable oils have been seen as promising surrogates to petroleum diesel in compression ignition internal combustion engines, showing similar performance and combustion characteristics of the fossil fuel. Nevertheless, the use of straight (crude) vegetable oil (SVO) is unfavorable due to its high viscosity, which affects the Sauter Mean Diameter of fuel spray and, consequently, fuel-air mixing process, resulting in incomplete combustion. The SVO heating, as well as transesterification and blending with diesel or additives, are some of the techniques to reduce its viscosity and enable its use. Of these the most simple and direct is the heating and was used in this paper to evaluate the performance and emissions of a diesel engine fueled with preheated soybean oil (PSO) by electrical resistances. The experiments were carried out in a single cylinder four-stroke compression ignition engine with mechanical fuel injection.

Internal Combustion Engines (ICE) have their use highly disseminated in the most diverse operations. Exhaust gaseous emissions and fuel consumption have been on the scope for decades and therefore the necessity for research on more efficient and lower exhaust emission engines has increased. Considering the cost of equipment and software to develop ICE, the use of computational models is a key strategy to evaluate the behavior of the powertrain/vehicle and lower the instrumentation cost. In this sense, the present work shows the development of an algorithm to obtain a high-resolution crank angle (CA) position of an engine by means of a toothed wheel instead of a high-resolution incremental or absolute encoder. As a result, it enabled the analysis of performance and combustion parameters based on in-cylinder pressure signals acquired through a piezoelectric pressure transducer and the angular position of the crank train referenced by a Hall Effect sensor.

Hydrous ethanol is pointed out as one of the major alternative fuel for internal combustion engines, because it is environmental friendly (almost zero CO2 emission) and has excellent combustion properties. Recent studies have shown that ethanol-water fuel blends with higher water content (so-called wet ethanol) can reduce the overall costs of ethanol production. The use of wet ethanol results in lower nitrogen oxides emissions at the cost of reduced lower heating value per mass of fuel blend, which may result in less thermal efficiency. On the other hand, the increase in water content improves knock resistance. Thus, this study aims to investigate the effects of mechanical compression ratio variation on a spark ignition engine using ethanol-water fuel blends containing 4, 10, 20 and 30% v/v of water in ethanol. The research was carried out in a SI single cylinder engine, port fuel injected, 0.668 dm3 with the compression ratio modified by spacer rings.

Intake tuning and ram effect are widely known methods to increase engine performance. This paper details the design, manufacturing and results of an intake system with active duct length variation for a CBR600RR 2008 engine, equipped with a restrictor downstream of throttle body, in accordance due to Formula SAE competition rules. The engine was discretized in Gamma Technologies' GT-Power software bundle, and with the aid of the computational tool Design of Experiments (DoE), the lengths and diameters of the inlet ducts and beyond the plenum volume were determined in order to increase the engine torque in the range of 6000 to 12000 RPM. After the dimensioning process, the assembly was modeled in CAD, analyzing the packaging requirements determined by the regulation and a better adaptation of the system to the prototype, and then fabricated, including the plenum, restrictor and intake manifold.

Concerns about global warming, pollutant emissions and energy security have driven research towards cleaner and more environmentally friendly fuels. In the same way as ethanol, butanol is a promising biofuel but with different characteristics such as higher calorific value and lower latent heat of vaporization. It has similar properties to those of gasoline, which makes it a potential surrogate for this fossil fuel. Therefore, the present study proposes a comparison among four different fuels i.e. n-butanol, n-butanol and ethanol blend (B73E27), gasoline and ethanol blend (G73E27), and hydrous ethanol. A single cylinder naturally aspirated research engine with port fuel injection was employed. Engine performance was experimentally evaluated and combustion parameters were determined through reverse calculation based on acquired intake, exhaust and in-cylinder pressure on GT-Power.

The performance required by the actual spark ignition engines have increased the demands on the cooling system. In addition, in formula style competitions like Formula SAE the use of aerodynamics brought new problems about airflow restriction, requiring a complex study in the heat exchange area. The ideal cooling system in this case uses a heat exchanger that will maintain the engine on the optimum working temperature. To make this possible the paper presents a methods of evaluating heat exchangers and to predict the heat generated by the engine. In order to get the data needed for the analysis, some experimental measurements are made, the water pump flow rate are measured and temperature sensors are added to both, cold and hot, fluids. The air velocity profile through the radiator core showed to be a very important factor in this situation, trying to predict it, CFD simulations have been used.

The current quest for clean and renewable fuels has prompted the appearance of several bio-mass fuel alternatives. Ethanol is a renewable biofuel obtained from different agricultural crops. The main production process to obtain anhydrous ethanol consists of crop production, mashing and cooking, fermentation, distillation and chemical dehydration. Some attractive characteristics of ethanol as a clean energy source is the CO2 absorption through photosynthesis during the crop plantation phase and positive ethanol life cycle energy balance. Even though, ethanol production cost is still relatively high when compared to fossil fuels. Knowing that a large energy amount is spent in the distillation phase, the use of hydrous ethanol as fuel, with high water content, can be economically attractive. This paper compares the use of high water-in-ethanol volumetric content fuel, varying from 5% to 40%, in a naturally aspirated 0.668-L single-cylinder port-fuel injected spark-ignited engine.

Electrical energy generators often use commercial diesel engines as a source of mechanical power at a fixed rotational speed. While the frequency of the grid cannot be modified, electric generators demand reciprocating engines to operate not always at their best efficiency range. By the use of a generator capable of running on different speeds and an electronic system that controls the output frequency, it is possible to operate the engines at their best efficiency load points. This paper describes the development of a variable speed diesel fueled electric generator with permanent-magnet high-efficiency synchronous generator. It was used a 1-D computational code to build a map through a mean-value model that combines speed and load to achieve the required power with the best engine efficiency. The generator set was instrumented whilebrake and indicated data were obtained in order validate the computational model.