Browse Topic: Multifuel engines

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High Power-Density, High Efficiency, Mechanically Assisted, Turbocharged Direct-Injection Jet-Ignition Engines for Unmanned Aerial Vehicles01-12-01-00025/2/2019
More than a decade ago, we proposed combined use of direct injection (DI) and jet ignition (JI) to produce high efficiency, high power-density, positive-ignition (PI), lean burn stratified, internal combustion engines (ICEs). Adopting this concept, the latest FIA (Fédération Internationale de l’Automobile) F1 engines, which are electrically assisted, turbocharged, directly injected, jet ignited, gasoline engines and work lean stratified in a highly boosted environment, have delivered peak power fuel conversion efficiencies well above 46%, with specific power densities more than 340 kW/liter. The concept, further evolved, is here presented for unmanned aerial vehicle (UAV) applications. Results of simulations for a new DI JI ICE with rotary valve, being super-turbocharged and having gasoline or methanol as working fuel, show the opportunity to achieve even larger power densities, up to 430 kW/liter, while delivering a near-constant torque and, consequently, a nearly linear power curve over a wide range of speeds.
Boretti, Alberto
Developing Small Variable Compression Ratio Engines for Teaching Purposes in an Undergraduate Program2019-01-03314/2/2019
The purpose of this paper is to summarize the progress achieved by the Combustion Engine Laboratory at Technological University of Pereira in the practical implementation of variable compression methods adaptable to small single cylinder industrial engines. Three alternatives to vary the compression ratio have been studied and realized: the first one consists on the modification of the combustion chamber of a commercial diesel engine and its conversion to a dual ignition engine (spark and compression ignition); the second alternative involves the change of the base slider-crank mechanism of a Petter PJ1 engine by a multi-link mechanism controlled to change the piston stroke as well as the compression ratio; and the third alternative consists on the complete design and construction of a novel eccentric cam-based mechanism, developed to vary the TDC piston position, by modifying the distance between the crankshaft and the cylinder head in a custom-built developed engine. The main goal of the project was to recognize and assess the possibility and means of modifying, adapting and building low cost variable compression ratio research engine units, for teaching purposes in Mechanical Technology program. To achieve this goal many design, technological, and experimental tasks were accomplished. The paper provides an overview of the VCR mechanisms developed.
Romero, Carlos Alberto, Henao Castañeda, Edison de Jesús
Canola Oil as a Fuel for Compression Ignition Engine – An Experimental Investigation2018-01-09104/3/2018
This work aims to discuss the practices required to address the effective utilization of Canola oil in compression ignition engine. Initially, raw canola oil was obtained using mortar and pestle method. In the second phase, transesterification of canola oil was done using methanol as the reacting agent and potassium hydroxide as the catalyst. The extracted biodiesel was then subjected to various standardization techniques and spectroscopic studies such as GC-MS (Gas Chromatography-Mass Spectroscopy), NMR (Nuclear Magnetic Resonance Spectroscopy) and FTIR (Fourier Transform Infrared Spectroscopy). In the third phase of the study, an engine test bench was developed with all suitable accessories. Instead of utilizing the neat form of canola biodiesel, an attempt was made to use the diesel and ethanol blends of canola biodiesel. The Variable load test was carried out using neat diesel and a best blend containing 30% by volume of canola biodiesel, 30% by volume of diesel and 40% by volume of ethanol (D30-CBD30-E40) at standard injection timing (i.e. 23oBTDC). In the next phase, the standard injection timing of best blend was advanced and retarded by 2o crank angle. Engine test results claimed that, brake thermal efficiency of best blend with advanced injection timing was increased by 23.1% as compared with standard injection timing. Advancement of injection timing had the benefits of reduced hydrocarbon, carbon monoxide and smoke emission at the penalty of slight increment in oxides of nitrogen emission. Cylinder pressure and heat release rate also found to be improved with advancement of fuel injection of the best blend.
Mayakrishnan, Jaikumar, Nandagopal, Sasikumar, Sathiyaseelan, Vasanthaseelan, Raja, Selvakumar
On the Entrainment Velocity and Characteristic Length Scales Used for Quasi-Dimensional Turbulent Combustion Modeling in Spark Ignition Engines2017-24-00029/4/2017
Quasi-dimensional modeling is used on a wide scale in engine development, given its potential for saving time and resources compared to experimental investigations. Often it is preferred to more complex CFD codes that are much more computationally intensive. Accuracy is one major issue of quasi-dimensional simulations and for this reason sub-models are continuously developed for improving predictive capabilities. This study considers the use of equivalent fluid velocity and characteristic length scales for simulating the processes of fresh charge entrainment and oxidation behind the flame front. Rather than dividing combustion into three different phases (i.e. laminar kernel, turbulent flame propagation and oxidation near the walls), the concept of turbulent heat and mass transfer is imposed throughout the entire process. Within this framework, the calibration of the two coefficients for fresh charge entrainment and oxidation behind the flame front was investigated, based on in-cylinder pressure and flame imaging recorded in a spark ignition (SI) engine fueled with gasoline, ethanol, methane and hydrogen. After the procedure of identifying the pairs of coefficients that ensured good accuracy during flame propagation, a more detailed analysis was performed with respect to the three combustion phases. These findings constitute the basis for developing mass transfer sub-models that ensure improved accuracy for multi-fuel operation of SI engines.
Irimescu, Adrian, Di Iorio, Silvana, Merola, Simona, Sementa, Paolo, Vaglieco, Bianca Maria
Development and Implementation of a Common Rail Fuel Injection System for Flexible Combustion for an Experimental Medium Duty Diesel Engine2017-01-07903/28/2017
In order to advance the current research engine to operate in advanced combustion modes such as reactivity controlled compression ignition RCCI a diesel common rail fuel injection system for the experimental research engine has been designed and developed through testing the hydraulic, electrical and electronics, mechanical subcomponents, and the controls strategies. This study presents the process taken based on the verification and validation model of design and development for the fuel injection system incorporating hardware-in-the-loop (HIL) testing prior to engine operation and subsequent engine validation. Software verification was completed through signal converting circuits to confirm precise injection timing and to test the system in a mean effective model to incorporate a PI speed controller along with consistent rail pressure. Initial operation of the common rail system integrated on the direct injected single-cylinder medium duty engine resulted in flexible combustion schemes with various injection timings and split patterns at a constant speed of 1500 RPM and 4.2 IMEP. Swept injection timing was tested from single pulses at 8°, 15°, and 22° before top dead center (BTDC) to multiple pulses starting at 60° BTDC. The original injection was at 15° BTDC and by delaying the timing to 8° BTDC, in-cylinder pressure reduced from 71 bar to 53 bar and the AHRR (apparent heat release rate) peaks decreased from 160 J/CAD to 70 J/CAD when comparing single pulse common rail events. These changes reduced NOx emissions by 98% but in turn dramatically increased soot and unburned hydrocarbons by over 10 times. Multi-pulse injection was also tested with 30% of mass injected at 60° BTDC and 70% at 8° and 22° BTDC. The AHRR displayed cool flames at 24° BTDC along with a reduced peak at 35 J/CAD and prolonged diffusion burn. These are preliminary results on a continually growing research engine. A port fuel injector (PFI) is also introduced into the intake manifold to conduct tests in RCCI mode with alternative fuels such as various Fischer Tropsch fuels and n-butanol. The spray pattern of the new piezoelectric injector was modeled to investigate the relation with excessive soot production. The results show that the new spray pattern impinges on the cylinder head with high levels of wall wetting and film formation resulting in a slow oxidation process with increased unburned hydrocarbons, and for these reasons a custom injector is being designed to resolve this issue. The new injection system and associated controls implementation of this system allows a flexible injection scheme and combustion phasing control nevertheless, the calibration is continuing including harmonization with the EGR and supercharger systems.
Soloiu, Valentin, Gaubert, Remi, Muinos, Martin, Moncada, Jose, Beyerl, Thomas, Molina, Gustavo
Mapping of Fuel Anti-Knock Requirements for a Small Remotely Piloted Aircraft Engine2016-32-004511/8/2016
Small remotely piloted aircraft (10-25 kg) powered by internal combustion engines typically operate on motor gasoline, which has an anti-knock index (AKI) of >80. To comply with the single-battlefield-fuel initiative in DoD Directive 4140.25, interest has been increasing in converting the 1-10 kW power plants in the aforementioned size class to run on lower AKI fuels such as diesel and JP-8, which have AKIs of ~20. It has been speculated that the higher losses (short-circuiting, incomplete combustion, heat transfer) that cause these engines to have lower efficiencies than their conventional-scale counterparts may also relax the fuel-AKI requirements of the engines. To investigate that idea, the fuel-AKI requirement of a 3W-55i engine was mapped and compared to that of the engine on the manufacturer-recommended 98 octane number (ON) fuel. The knock limit was established to be a peak-pressure rise rate of 5 bar/deg or a maximum amplitude of pressure oscillations of 5 bar for 1% of 400 consecutive cycles, whichever was more conservative. The 3W-55i engine was able to develop full power at all speeds above 6000 rpm (which included the peak power of 5 kW between 6500 and 7000 rpm) running on a 20 ON primary reference fuel (PRF) blend. Below 6000 rpm engine performance was knock-limited on the 20 ON PRF blend, resulting in up to a 30% decrease in power at some operating points. The results validate the speculation that losses in small engines can permit a direct conversion to low-AKI fuel with minimal impact on engine performance.
Ausserer, Joseph K., Polanka, Marc D., Litke, Paul, Baranski, Jacob
Sound and Vibration Levels of CI Engine with Synthetic Kerosene and n-Butanol in RCCI2016-01-13064/5/2016
Diesel engines provide the necessary power for accomplishing heavy tasks across the industries, but are known to produce high levels of noise. Additionally, each type of fuel possesses unique combustion characteristics that lead to different sound and vibration signatures. Noise is an indication of vibration, and components under excessive vibration may wear prematurely, leading to repair costs and downtime. New fuels that are sought to reduce emissions, and promote sustainability and energy independence must be investigated for compatibility from a sound and vibrations point-of-view also. In this research, the sound and vibration levels were analyzed for an omnivorous, single cylinder, CI research engine with alternative fuels and an advanced combustion strategy, RCCI. The fuels used were ULSD#2 as baseline, natural gas derived synthetic kerosene, and a low reactivity fuel n-Butanol for the PFI in the RCCI process. This combination of fuels was never analyzed from NVH point of view in RCCI mode. The sound and vibration signatures were measured using a B&K condenser type microphone and a piezoelectric, triaxial accelerometer. The data were analyzed with CPB and FFT Analysis, and Angle Domain Analysis with B&K Pulse platform software. The tests were conducted at 1500 rpm and 4 bar IMEP load, with 40% EGR, and 65% by mass PFI of n-Butanol. The COV for RCCI with S-8 and ULSD#2 were 5.14 and 4.80, respectively. The max values of the heat release for RCCI was 97 and 112 J/CAD for S-8 and ULSD#2, respectively. The results indicated that a difference of 5.5 dB(A) was achieved between RCCI with S-8, and RCCI with ULSD#2.
Soloiu, Valentin, Simons, Emerald, Muinos, Martin, Harp, Spencer, Knowles, Aliyah, Molina, Gustavo
Automotive Direct-Injection Stratified-Charge Engine Development in the 1970-1980’s2016-01-01754/5/2016
Spark-ignition direct-injection technology existed since about 1930 for the primary purpose to give multifuel capability over what the compression-ignited diesel engine could provide. In subsequent decades development of multifuel engines continued both as higher-compression-ratio “spark-ignited diesel” and moderate-compressionratio stratified-charge engines. Global events in the 1960-1970’s, namely the oil embargo, oil-supply crises, and the passage of the U.S. Clean Air Act intensified interest in such engines. The military and large commercial fleet operators were particularly focused on efficiency and multifuel capability over concerns for fuel supplies. Automobile manufacturers were focused on gasoline-fueled efficiency and the potential to reduce engine-out legislated NOx emissions with the stratified-charged combustion systems. In this paper the major direct-injection spark-ignited stratified-charge concepts pursued during the 1970-1980’s are reviewed at a high level, and relevant references are cited. Examination of this development history should be of interest to those working on modern gasoline direct-injected engines, as a variety of concepts were pursued, with the physics of those combustion processes being pertinent to today’s systems in production and under development. In many cases advances in fuel-injection hardware, enabled by modern manufacturing methods, and control technologies, enabled by modern computers and sensors, have allowed design objectives of the past to be implemented successfully today.
Groff, Edward G.
Vehicle Speed Recovery Test Methodologies on Chassis Dynamometer and their Correlation with Track Test Results2015-36-01969/22/2015
Fun to drive is one of the main driver’s wishes. Therefore, it is a relevant attribute in vehicles and fuels development. Vehicles performance depends, mainly, on ignition and fuel injection strategies adopted by their manufacturers. However, fuel characteristics may significantly influence acceleration and speed recovery results. Regarding fuel development, it is important to establish test methodologies, which minimize experimental uncertainties. So, it is possible to detect any small acceleration or speed recovery variation and relate it to fuel characteristics changes. An alternative to traditional track tests is to perform speed recovery tests on chassis dynamometer, where it is possible to mitigate the effect of some parameters which may significantly vary on track, such as, ambient temperature, ground irregularities and wind direction and speed. In this paper, chassis dynamometer speed recovery test methodologies are proposed and their results are compared to those obtained on track tests, using two vehicles. Results confirmed that the new proposed methodologies represent an improvement on speed recovery tests, due to lower experimental dispersions and uncertainties. It was also measured the driver’s influence on speed recovery tests.
Villela, Antonio Carlos Scardini, Botero, Sérgio William, de Carvalho, Rogério Nascimento
Experimental Study of Combustion for Mixtures of Ethanol and Ignition Improvers in a Rapid Compression Machine2015-36-00909/22/2015
Over the past decades, researchers from different countries that produce oil or not, have intensified their research in order to develop more efficient systems. It is not unknown to the world that the main source of energy used in transport is the diesel oil, to be more economical and more efficient. For this reason, various sectors of transport and fuel producers are developing new technologies in order to replace fossil fuels with other renewable sources. Nowadays it is possible to find on the market engines that run on blends of diesel and other renewable fuels and systems that work with mixtures of ethanol and additives. To be able to use ethanol in compression ignition engines, the main problem to be overcome is the poor flammability of the ethanol under compression ignition conditions. This problem is generally attributed to the high enthalpy of vaporization of ethanol and the need for higher autoignition temperatures when compared to diesel. The option to adapt the fuel to the engine, by increasing the quality of autoignition, is typically made through the use of additives. In this work, different tests were carried out in a rapid compression machine using ignition improvers for ethanol from the use of polyethylene glycol. Tests were conducted for different start of injection instants of the mixture and different compression ratios. The results show the behavior of combustion for these different techniques for injecting fuel, with different concentrations of ignition improvers with compression ratios of 16:1, 20:1 and 25:1.
Sánchez, Fernando Z., Braga, Carlos V. M., Braga, Sergio Leal, Dias, Flávio G., Turkovics, Franck Y., Airoldi, Marcelo L., De Souza, Renata N. C.
Theoretical Reduction in NOx Emissions Using a Torch Ignition System Operating with Homogeneous Charge2015-36-04769/22/2015
The pollutants emitted by fuel burn in an internal combustion engine are harmful to humankind health. One of undesirable pollutants are the nitrogen oxides (NOx), witch in the presence of sunlight is responsible by photochemical mist, forming products that irritates eyes, respiratory system and may damage plants. The present article aims to present the theoretical potential reduction in volumetric emissions of nitrogen oxides (NOx) in an internal combustion engine operating with the torch ignition system and homogeneous charge. Therefore, a calculation methodology based in measured pressures and determined temperatures were implemented to check the potential reduction in these pollutant emissions. The presented methodology used to estimate the NOx formation is based in NO formation model presented by [1]. This model uses the ZELDOVICH mechanism to nitric oxide formation and were inserted an adjustment coefficient (CA) in the NO formation rate equation, in order to calibrate the model to the baseline engine operating with stoichiometric mixture. The obtained results point a potential reduction around 70% in NOx emissions.
Moreira, Thiago Augusto Araújo, Fernandes, Luiz Antônio Pires, Pires, Marcelo Augusto Maia, Neves, Arthur Castilho, Duarte, Vinícius Faria, Barros, José Eduardo Mautone, Valle, Ramon Molina
Robust Emission Compliance and Reduction of System Cost by advanced emission-based Diesel engine air management2015-26-00891/14/2015
The continuously strengthened requirements regarding air quality and pollutant reduction as well as GHG emissions further complicate the compliance with legal standards. Especially in view of cost-sensitive applications this demand strongly collides with the EMS set-up and the sensor requirements with still increasing overall system complexity. The paper in hand describes a novel air path control approach, which offers the potential for a flexible use of multiple EGR routes to meet upcoming legislations more robustly, while providing a significant reduction of calibration effort and sensor content at the same time. By using a direct emission based cylinder charge control, also alterations in operational ambient conditions are covered with system reactions according to physical-based rules to enhance the engine-out emission performance without need for tuning of corrections of any air path set point. This enables a system to fulfil EU-4 and EU-5 emission requirements in very cost attractive way, but also to meet EU6.2 and RDE legislation requirements with slightly increased sensor set-up, while using the same software strategies. In addition to the functional correlations and principle layout of the novel algorithms, the paper delivers also validated experimental results for a clear proof-of-concept and identifies the merits in engineering and calibration effort.
Schaub, Joschka, Schnorbus, Thorsten, Miccio, Michele, Koerfer, Thomas
Using Fractal Modeling to Predict Flex-Fuel Engine Combustion Process with Different Gasoline-Ethanol Blends2014-36-01629/30/2014
Combustion Modeling of Internal combustion engines is still a complex matter, requiring further developments to better simulate the performance and emissions of different fuels. In order to study the influence of gasoline-ethanol blends on a Flex-Fuel engine, a computer model was designed to simulate the experimental conditions using Fractal combustion and Woschni based heat transfer models. The simulations were validated with engine dynamometer experimental tests. In-cylinder maximum pressure, IMEP and emissions data were calculated for different gasoline-hydrous ethanol blends at different engine conditions. The computer model presented a predictive behavior and a good agreement with experimental data for in-cylinder maximum pressure and IMEP. Regarding emissions, the simulations of some pollutants could not match precisely the experimental data, showing the need for additional combustion modeling improvements.
de Melo, Tadeu Cavalcante Cordeiro, Machado, Guilherme Bastos, Matias, Filipe Augusto Serrão
Influence of Methanol Induction on Performance, Emission and Combustion Behavior of a Methanol - Diesel Dual Fuel Engine2014-01-13154/1/2014
Experimental work was carried out to evaluate the performance, emission and combustion characteristics of a dual fuel engine with diesel as pilot fuel and methanol as inducted primary fuel. A single cylinder water cooled direct injection diesel engine developing a power output of 3.7kW at 1500 rev/min. was modified to work in the dual fuel mode. Tests were conducted at fixed loads such as 100%, 80%, 60% and 40% of the maximum power output with varying methanol induction rates. Brake thermal efficiency in dual fuel operation was better than normal diesel operation with methanol induction mainly at high power outputs. It increased from 30.3% with neat diesel to a maximum of 32.7% when methanol contributed about 44% of energy share. Smoke was reduced significantly with all methanol induction rates at all power outputs in dual fuel operation with diesel as pilot fuel. It was reduced from 3.8 BSU to 1.8 BSU with diesel at the maximum efficiency point at 100% load. NO emission was found lower in dual fuel operation at all loads and all methanol admission rates. This trend was noted mainly due to the reduction in the charge temperature due to vaporization of methanol. However, there was an increase in HC and CO emissions with methanol induction in dual fuel operation. Cylinder peak pressure and maximum rate of pressure rise were found as higher with methanol induction as compared to neat diesel operation mainly at high power outputs due to improvement in combustion. At low power outputs due to misfire peak pressure and maximum rate of pressure rise were reduced. Ignition delay and combustion duration were observed to be higher with methanol induction as compared to neat diesel operation all power outputs. Heat release rate resulted in improved premixed combustion phase with methanol induction mainly at high power outputs. However, at very high rates of methanol induction, premixed combustion phase became inferior due to misfire. It was concluded that diesel as pilot fuel and methanol as the inducted primary fuel could reduce smoke and NO levels significantly in a dual fuel engine with improved thermal efficiencies. However, care must be taken for controlling HC and CO emissions. In addition poor part load performance must be paid attention.
Masimalai, Senthil Kumar
Design and Construction Methodology of a Stratified Torch Ignition System2013-36-056210/7/2013
It developed a design and construction methodology of a stratified charge torch ignition system for an Otto engine aiming fuel consumption and pollutant emission reduction. The torch ignition system is made of a combustion pre-chamber equipped with a direct fuel injector, an air injector and a spark plug. Fuel is directly injected in the pre-chamber aiming the formation of a lightly rich air fuel mixture. The combustion process starts in the pre-chamber and as the pressure rises, combustion jet flames are produced through interconnection nozzles into the main chamber. The high thermal energy of the jet flames reduces the combustion time, increases the combustion efficiency and allows the engine to efficiently burn lean air fuel mixture of several kinds of fuel in the main chamber, even those that are difficult to ignite. After the combustion takes place in the pre-chamber, air is also injected to help the exhaust process of the combustion products of the previous cycle. Theoretical calculus was made to determine the main geometrical parameters of the pre-chamber, such as volume and the number and diameter of the interconnection nozzles. Since the system designed is equipped with two independent fuel injection systems, one for the pre-chamber and another for the main chamber, it is possible to burn an stoichiometric air fuel mixture in the pre-chamber and a lean air fuel mixture of a different fuel in the main chamber. Therefore a multifuel stratified charge torch ignition engine is obtained.
Moreira, T. A. A., Filho, F. A. Rodrigues, Gonçalves, L.A.R., Barros, J. E. M, Pujatti, F. J. P., Valle, R. M
Image Processing Applied to Flame Propagation and Ignition Delay Measurements in a Rapid Compression Machine2013-36-029610/7/2013
Regarding fuels research and development, some preliminary studies - low cost and short time - can be conducted before the traditional engine tests - more expensive and time consuming. Therefore, experimental apparatus, such as a rapid compression machine (RCM) and specific methodologies, such as imaging techniques, are very useful in order to simulate engine combustion with simplicity, agility and flexibility, reducing development time and costs. Imaging techniques allow flame front propagation and ignition delay analysis, which are important parameters to understand fuel performance in engines and also to improve fuel modeling in engine simulation softwares. A RCM was adapted to operate in a spark ignition engine mode. It was used to obtain high-speed photos of flame propagation and ignition delay. Contour plots of the flame front profiles were obtained in successive frames to analyze the flame development with gasoline-ethanol blends. Based on a software code, it was determined the flame size in each frame. The flame area, in pixels and the frame ratio were previously established. Then, it was possible to calculate the flame growth ratio, in pixels per frame. The results were compared to published propagation speed data.
Villela, Antonio Carlos Scardini, Botero, Sergio William, Machado, Guilherme Bastos, Egúsquiza, Julio César, Braga, Leonardo C., Braga, Sergio L., Braga, Calos Valois M.
A Semi-Physical Artificial Neural Network for Feed Forward Ignition Timing Control of Multi-Fuel SI Engines2013-01-03244/8/2013
Map-based ignition timing control and calibration routines become cumbersome when the number of control degrees of freedom increases and/or a wide range of fuels are used, motivating the use of model-based methods. Purely physics based control techniques can decrease calibration burdens, but require high complexity to capture non-linear engine behavior with low computational requirements. Artificial Neural Networks (ANN), on the other hand, have been recognized as a powerful tool for modeling systems which exhibit nonlinear relationships, but they lack physical significance. Combining these two techniques to produce semi-physical artificial neural network models that can provide high accuracy and low computational intensity is the focus of this research. Physical input parameters are selected based on their sensitivity to combustion duration prediction accuracy. Input models for the four most critical physical parameters are derived: (1) residual gas fraction, (2) laminar flame speed, (3) turbulence intensity, and (4) total in-cylinder mass. The ANN structure is described and the minimum number of required nodes is determined. The semi-physical ANN ignition timing prediction model is validated in a multi-fuel engine using experiments and simulations. The routine is experimentally validated using gasoline and E85 under both steady-state conditions in a dynamometer cell. The method is also validated using a combination of control software and one-dimensional engine-specific simulation over regulated drive-cycles. Results from experiment and simulation demonstrate that combustion phasing is controlled to within two to three crank angle degrees of the target value for operating conditions within the bounds of the original training data set.
Xiao, Baitao, Wang, Shu, Prucka, Robert G.
Multifuel Engine Performance, Emissions and Combustion Using Anhydrous and Hydrous Ethanol2012-36-047510/2/2012
The increasing ethanol participation in Brazilian fuel market and its supply and price oscillations, motivate studies on multifuel engines behavior with the two specified types of ethanol in Brazil, the anhydrous and the hydrous fuels. The present work includes a comparative engine test bed performance study of a multi-fuel engine equipped with a programmable electronic central unit (ECU), fueled with anhydrous and hydrous ethanol. Fuel properties, engine performance, emissions and combustion parameters are reported using these two fuels for maximum power operating point. The programmable ECU was installed in order to make possible the setting of some parameters that are not accessible in engines operating with commercial ECU. This way, torque was optimized regarding spark timing and air fuel ratio, for all selected fuels and engine conditions tested. Test results presented the effects of anhydrous and hydrous ethanol on a multi-fuel engine performance, emissions and combustion. Additionally, some performance and emissions correlations with combustion parameters are presented.
Villela, Antonio Carlos Scardini, Machado, Guilherme Bastos
Computer Simulation of a Flex-Fuel Engine Running on Different Gasoline-Hydrous Ethanol Blends2012-36-048710/2/2012
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. The computer model presented good agreement with experimental data for maximum in-cylinder pressure, intake air, fuel_consumption and IMEP. Regarding emissions, the simulations could not match experimental data without specific adjustment for each fuel, showing the need for further modeling development.
de Melo, Tadeu Cavalcante Cordeiro, Machado, Guilherme Bastos, Belchior, Carlos Rodrigues Pereira, Colaco, Marcelo Jose, Barros, Jose Eduardo Mautone, de Oliveira Gatto, Daniel, Paiva, Carlos Eduardo Fernandes
In Cylinder Pressure Curve and Combustion Parameters Variability with Ethanol Addition2012-36-048610/2/2012
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.
de Melo, Tadeu Cavalcante Cordeiro, Machado, Guilherme Bastos, de Oliveira Carvalho, Leonardo, Belchior, Carlos Rodrigues Pereira, Colaco, Marcelo Jose, Barros, Jose Eduardo Mautone, Paiva, Carlos Eduardo Fernandes
Gasoline-Ethanol Combustion Study in a Rapid Compression Machine2012-36-047410/2/2012
Combustion images are not simple to be obtained in conventional engines. Therefore, some experimental apparatus, such as a rapid compression machine (RCM), are useful to conduct this kind of study. Imaging techniques allow flame front propagation analysis, which is a very important parameter to understand engine performance, using different fuels and also to generate data to improve fuel modeling in engine simulation softwares. A RCM was adapted to operate in a spark ignition engine mode. It was used to obtain cylinder pressure measurements of gasoline-ethanol combustion synchronized with high-speed photos of flame propagation. Contour plots of the flame front profiles, assumed to be spherical, were used in successive frames to calculate the propagation speeds toward the cylinder walls. So, it was possible to correlate images, pressure curves and flame speeds of gasoline-ethanol blends. The results obtained with this device will be used in the future to make correlations with engine tests. The objective is to develop a new methodology that can lead to the engine tests, resources and cost reduction in fuel development processes.
Villela, Antonio Carlos Scardini, Machado, Guilherme Bastos, Braga, Carlos Valois Maciel, Egusquiza, Julio Cesar Cuisano, Braga, Sergio Leal
Procedure for Uncertainty of Measurement Determination of Spark Ignition Engine Emission Tests2012-36-048810/2/2012
Experiments in engine test cells are under the influence of several parameters and types of equipment, which may impact the test results. Many variables of interest are derived from the combination of more than one quantity, increasing the results uncertainty of the final reported value. This paper describes a detailed procedure to calculate uncertainty of measurement of emission tests using a FTIR (Fourrier Transformed Infrared) emission analyzer. A Flex-Fuel engine using gasoline and ethanol was tested under different operating conditions on an engine dynamometer equipped with automation system. For each operating condition at least four different measurements were taken. The expanded uncertainty was calculated by the combination of Type A (due to repeatability) and Type B (due to calibration, sensor resolution and others).
de Melo, Tadeu Cavalcante Cordeiro, de Brito, Marcos Fernando Mendes, Machado, Guilherme Bastos, Paiva, Carlos Eduardo Fernandes
Benchmarking a 2-Stroke Spark Ignition Heavy Fuel Engine2012-01-03974/16/2012
Heavy fuel engines have typically been limited to large, heavy compression ignition engines. However, with the push by the US military to use a common fuel (JP5/JP8/diesel) there is a need to develop small, lightweight, high performance engines that are also capable of operating on heavy fuel. Recent advancements in air assisted direct injection technologies have improved fuel atomization to the level necessary to overcome the poor physical properties of heavy fuel. This has permitted the operation of small two-stroke engines which retain the advantage of a lightweight design with high power output. This paper discusses the process of benchmarking a two-stroke heavy fuel spark ignited engine with an integrated air-assist direct injection system. The setup and commissioning phases of the testing are outlined, including specific techniques for quantifying scavenging, burn rate, and heat release characteristics with the objective of validating a 1-D performance simulation model. Additionally, design features and performance attributes of the engine and the air assisted direct injection system are discussed.
La, Chi, Murphy, Patrick, Cakebread, Stephen
Novel Engine Concepts for Multi Fuel Military Vehicles2012-01-15142/29/2012
The paper considers different options to design a multi fuel engine retaining the power densities and efficiencies of the latest Diesel heavy duty truck engines while operating with various other fuels. In a first option, an igniting Diesel fuel is coupled to a main fuel that may have any Cetane or octane number in a design where every engine cylinder accommodates a direct Diesel injector, a glow plug and the multi fuel direct injector in a bowl-in-piston combustion chamber configuration. Alternatively, an igniting gasoline fuel replaces the Diesel fuel in a design where every engine cylinder accommodates a gasoline direct injector, the multi fuel direct injector and a jet ignition pre chamber also with a bowl-in-piston combustion chamber configuration. Both these designs permit load control by changing the amount of fuel injected and Diesel-like, gasoline-like and mixed Diesel/gasoline-like modes of operation modulating the amount of the multi fuel that burn premixed or diffusion. The paper only covers engine performance simulations for operation Diesel-like and gasoline/HHCI-like, being the simulations of the mixed Diesel/gasoline-like modes currently not available. The new designs have the potential to deliver even better than current heavy duty truck Diesel fuel conversion efficiency both part load and full load operating with variable quality fuels.
Boretti, Alberto
Rapid Compression Machine Tests for Brazilian Otto Cycle Fuels2011-36-034910/4/2011
Rapid Compression Machine (RCM) is an experimental tool developed to study engine combustion parameters. The RCM used is a pneumatically and hydraulically driven device which reproduces a single combustion shot, considering a compression and a partial expansion stroke. This paper describes RCM adaptations made in order to run Otto cycle tests using Brazilian regular gasoline (E25) [1]. These adaptations enable pre-vaporized air-fuel mixture combustion tests, representative of port fuel injection engines, by using a gasoline direct injection (GDI) injector. It is also presented RCM piston displacement and cylinder pressure comparisons to a real engine and RCM comparative results for different spark timings and compression ratios. These results show that RCM reproduced satisfactorily piston displacement and pressure curves during the combustion shots, when compared to real engine curves. It also shows that RCM changes in spark timing and compression ratios followed the same trends that were expected by engines’ theory. It was possible to confirm that RCM is able to reproduce engine combustion, using very small fuel volume and changing parameters that are not easily and quickly adjusted in a conventional engine test bench. These aspects may reduce research and development time and cost.
Villela, Antonio Carlos Scardini, Egúsquiza, Julio César Cuisano, Machado, Guilherme Bastos, Braga, Sérgio Leal
Numerical Simulation of Adaptive Combustion Control for Fuel-Neutral ‘Smart’ Engines2011-01-08484/12/2011
The search for next generation transportation fuels in order to fully or partially replace petrol based fuels has resulted in use of varieties of fuels and fuel blends in internal combustion engines. However, the engine management systems are fuel specific and therefore, every major change in fuel composition requires significant amount of calibration work to optimize the operating variables in order to meet legislative emission targets and reduce the real-world emission and improve fuel economy levels. The current work has successfully devised a numerical simulation for the operation of a modern 4-cylinder turbocharged engine using an adaptive combustion modelling methodology that identifies a fuel type during engine start itself, and adapts engine operating parameters for optimum performance. A strategy was devised to use commercially available sensors to obtain and correlate measurable cylinder pressure based information for fuel identification. The engine model for a 1.6L turbocharged GDI engine was built in 1-D code and fully validated with measured data. This model was used to simulate combustion of four different fuels and build fuel specific correlations for engine start and higher operating speeds. Correlations for peak pressure, rate of pressure rise and emissions were used to develop strategies for fuel identification. Finally, these strategies were implemented using a GT-POWER-MATLAB coupling, for demonstration of the ‘smart’ engine operation. This report presents a detailed step-by-step methodology for the model validation, drawing up of the operating correlations and strategies, and implementation of the same through a program code.
Divakera, Arjun, Samuel, Stephen
Individual Cylinder Fuel Control Application with a Switching Oxygen Sensor2010-36-002810/6/2010
In this paper we discuss in detail an algorithm that addresses cylinder-to-cylinder imbalance issues. Maintaining even equivalence-ratio (θ) control across all the cylinders of an engine is confounded by imbalances which include fuel-injector flow variations, fresh-air intake maldistribution and uneven distribution of Exhaust Gas Recirculation (EGR). Moreover, in markets that are growing increasingly cost conscious, with ever tightening emissions regulations, correcting for such mismatches must not only be done, but done with no additional cost. To address this challenge, we developed an Individual Cylinder Fuel Control (ICFC) algorithm that estimates each cylinder's individual θ and then compensates to correct for any imbalance using only existing production hardware. In our production-bound algorithm, modeling and control of the cylinders' dynamic θ was performed using a single switching oxygen sensor. Our ICFC algorithm was developed on a 2.4-l four-cylinder DOHC engine and it is in production at 2010 Multifuel engines 1.0, 1.4 and 1.8L four-cylinders SOHC selling a volume of 90 k/year. It meets internally defined performance requirements and NLEV emissions. Other important contributions in this work include an analysis of exhaust gas transport and mixing phenomenon, and an analysis of digitally acquiring and post processing oxygen sensor data.
Krenus, Roberto G., Costa, Herbert L.
Opposed Piston EnginesR-37810/8/2009
This book explores the opposed piston (OP) engine, a model of power and simplicity, and provides the first comprehensive description of most opposed piston (OP) engines from 1887 to 2006. Design and performance details of the major types of OP engines in stationary, ground, marine, and aviation applications are explored and their evolution traced. The OP engine has set enviable and leading-edge standards for power/weight refinement, fuel tolerance, fuel efficiency, package space, and manufacturing simplicity. For these reasons, the OP concept still remains of interest for outstanding power and package density, simplicity, and reliability; e.g., aviation and certain military transport requirements. Using material from historic and unpublished internal research reports, the authors present the rationale for OP engines, their diverse architecture, detailed design aspects, performance data, manufacturing details, and leading engineers and applications. Comparisons to four-stroke and competitor engines are made, supporting the case for reconsidering OP engines for certain applications. Topics include: The history of OP engines Aeronautical Automotive Military Marine Unusual OP engines Comparison between 2 and 4 stroke engines The future of OP engines and more
Flint, Martin L.S., Pirault, Jean-Pierre
Board Recognition of Different Fuels Feeding SI Engines with the Use of Dimensional and Nondimensional Vibration Signal Parameters-Part 12009-01-20565/19/2009
The availability of gaseous fuels such as natural gas and propane butane mixtures has led to worldwide popularity of internal combustion engines running dual fuel or alternatively gas powered. These gaseous fuels are known as fuels more resistant to knocking than conventional liquid fuels and as less ones pollutant. Their better mixing with air is also well recognized. There are some works published on the use of gaseous fuels, but the problem of the combustion noise, as a very important source of information regarding the combusted fuel, is not receiving much attention. Combustion noise occurs in two forms, direct and indirect. It is transmitted throughout the engine block as a vibration at a different spectrum of frequencies. In this study an attempt is made to relate the combustion noise to the operating parameters for LPG, CNG and Hydrogen enriched CNG powered engine as compared to petrol fueled engine. Combustion pressure and vibration of cylinder block data are measured and presented in case of engine running on gaseous fuels and compared to the results obtained for engine fed by petrol. The ability to recognize the fuel type feeding the multi-fuel engine would certainly make it possible to automatically adjust both fuel and ignition system setup, allowing the optimal fuel energy utilization. The first part of the methodology based on selected vibration signal parameters for the purposes of fuel type recognition, has been presented in the paper. The following parameters have been mentioned: scalogram and wavelet coefficient increase. Signals of multiple resonances in combustion chamber and corresponding vibration signals of cylinder block of engine were examined for one combustion cycle. Tests were completed on a four cylinder, 1.6L spark-ignition engine converted to run on gaseous fuels in this project. The engine test stand was fully computerized and the cylinder pressure data, acceleration of vibration of engine block, crank angle data were stored on a PC. The influence of engine speed, load on combustion and engine block vibration were examined for all fuels. A few of well known diagnostic parameters were used for comparison of engine noise operated on petrol and gaseous fuels.
Flekiewicz, M., Fabiś, P., Flekiewicz, B.
Technological Solutions for Urucu Natural Gas Usage in Light-Duty Vehicles2008-36-020710/7/2008
In last few years, Petrobras has been working to make feasible the vehicular usage of the natural gas (NG) produced in Brazilian north region. This gas is produced in the Urucu field located at the Amazon forest. Due to its low methane and high nitrogen contents that could promote, respectively, performance losses and higher NOx emissions, Urucu's gas does not meet ANP specification for vehicular natural gas. Previous studies performed at Petrobras Research Center (CENPES) indicated the possibility of vehicular application for Urucu's NG, attending the Brazilian emission legislation (PROCONVE). However, with new PROCONVE's phases, recent vehicles have more advanced technological levels of fuel injection and catalyst systems, which require that kits for natural gas follow this evolution, including interfacing with flexible fuel engines. In a new research project, CENPES observed that only with fifth generation NG kits, based on electronically controlled injection of positive gas pressure, was possible to obtain a proper calibration to reach current emission limits. Urucu's NG was also assessed in an national OEM natural gas vehicle that runs with NG and liquid fuels.
de Carvalho, Rogério Nascimento, Villela, Antônio Carlos Scardini, de Melo, Tadeu Cavalcante Cordeiro
Performance Study of a Multifuel Engine Operating Simultaneously with CNG and Ethanol in Various Proportions2008-36-028410/7/2008
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. The present investigation is a pioneer study concerning the simultaneous use of CNG and ethanol and is a breakthrough in the development of new management strategies on a flexible engine. The ethanol-CNG mixture proportion and the stoichiometry could be set according to the torque demand but always giving priority to the CNG, with results on low BSFC (compared to the exclusive use of ethanol).
Burger, Paulo Roberto Bomfim, Baêta, José Guilherme Coelho, Valle, Ramón Molina
Investigation on Differences in Engine Efficiency with Regard to Fuel Volatility and Engine Load2008-01-238510/6/2008
An HSDI Diesel engine was fuelled with standard Swedish environmental class 1 Diesel fuel (MK1), Soy methyl ester (B100) and n-heptane (PRF0) to study the effects of both operating conditions and fuel properties on engine performance, resulting emissions and spray characteristics. All experiments were based on single injection diesel combustion. A load sweep was carried out between 2 and 10 bar IMEPg. For B100, a loss in combustion efficiency as well as ITE was observed at low load conditions. Observed differences in exhaust emissions were related to differences in mixing properties and spray characteristics. For B100, the emission results differed strongest at low load conditions but converged to MK1-like results with increasing load and increasing intake pressures. For these cases, spray geometry calculations indicated a longer spray tip penetration length. For low-density fuels (PRF0) the spray spreading angle was higher. It was concluded that both, the spray geometry and the slightly longer injection event influence fuel air mixture generation disadvantageous at low load conditions. An intake pressure variation showed that ignition delay (ID) shortened considerably for all fuel types. For B100, HC emissions as well as ITE improved with higher intake pressures. This behaviour was explained by improved spray characteristics and ambient gas conditions during the injection event.
Horn, Uwe, Egnell, Rolf, Andersson, Öivind, Johansson, Bengt, Rijk, Erik
Injection System Control for a Multi-Fuel SI Engine2008-01-17296/23/2008
In this paper, the dependency on fuel blends of a four stroke, four cylinder SI engine equipped with a low pressure common rail type injection system is analyzed. With reference to an operating condition using E21 (21% ethanol, 79% gasoline) as a fuel, the experimental performance of the engine are firstly introduced, and the brake power, the specific fuel consumption, the total efficiency, the heating combustion power and the injected mass per stroke dependency on shaft speed are introduced. Then, the multi-fuel injection system actual behavior is predicted by means of a properly tailored lumped and distributed numerical model, whose general reliability is defined mainly in terms of injected mass per stroke. Afterward, the engine performance variation with the fuel mixture is determined, and the adaptation of the PWM control applied to injectors is proposed to compensate the engine operating characteristics. Finally, with reference to the engine performance using E100 (100% ethanol, 0% gasoline) as a fuel, the influence of the engine rotational speed on the injected mass per stroke, on the heat of combustion power, on the specific fuel consumption and on the brake power are introduced, and the numerical prediction reliability is assessed with respect to the engine experimental behavior.
Bottazzi, D., Franzoni, F., Milani, M., Montorsi, L., Luppi, M., Osbat, G.
Numerical Analysis of the Fuel Mixing Process in a Multi-Fuel Injection System2008-01-16416/23/2008
The paper focuses on the mixing process of different fuels in a multi-fuel low pressure common rail injection system for a four stroke SI engine. The study is devoted to the prediction of the fuel mixture delivered by the injectors during a transient in which gasoline is being replaced by ethanol or a gasoline/ethanol blend. An integrated approach of different numerical tools is used to model the rail dynamic behavior under actual operating conditions. First, the 1D model of the injection system is constructed and the time varying conditions at the accumulator inlet and at the injectors' boundaries are assessed. The second step of the study is centered on the CFD analysis of the mixing process within the rail. The effects of the different engine operations on the fuels mixing are investigated and the injected fuel distribution among the cylinders is calculated. An open source computational fluid dynamics code is used in the simulations. The modified VOF approach, used for modeling the fluid-fluid mixing process, is tailored in order to account for the turbulence effect.
Franzoni, F., Milani, M., Montorsi, L.
In Cylinder Pressure Curve Simulation On Multifuel Engines - A Comparison Between A Polytrophic And General Thermodynamic Model For Gasoline, Ethanol And Natural Gas2007-01-282011/28/2007
Brazil is known for its long experience on using alternative fuels, mainly ethanol for light duty vehicles. In 2002, it was released the Flexible fuel car that can run with gasohol (gasoline with 22% of ethanol), hydrated ethanol or any blend of these fuels. By the end of 2006, national production of these vehicles represented around 80% of the total. Brazil is also the second world fleet of Natural Gas Vehicles (NGV), with more than 1,4 million light duty converted vehicles. This paper describes the development of a computational thermodynamic model of compression, combustion and expansion processes of gasohol, ethanol and Natural Gas (NG) for the cylinder pressure curve prediction of a Flexible Fuel engine, working with a NG kit installed. The combustion process is modeled using a Wiebe function, which establishes the mass fraction of burned fuel. Convective heat transfer to cylinder walls is estimated with an empirical correlation for heat transfer coefficient determination. Equations for specific heat at constant pressure varying with temperature, not available on literature, were developed for each fuel for temperatures over 4000 K. The model output generates the cylinder gas pressure profiles as functions of crank angle for two different approaches. One, solving the differential equation system assuming a polytrophic process after the intake valves closure and before the combustion start and the other by solving the whole system since the intake valve closure. A Flexible fuel engine, 1.8 liter with NG kit, operating with gasohol, hydrated ethanol and NG on different conditions of speed and load, was used to validate the simulations. Results show that the general model is much more precise than the polytrophic simplified approach.
de Melo, Tadeu Cavalcante Cordeiro, Machado, Guilherme Bastos, Machado, Renato Tristão, Belchior, Carlos Rodrigues Pereira, Pereira, Pedro Paulo
Thermodynamic Modeling of Compression, Combustion and Expansion Processes of Gasoline, Ethanol and Natural Gas with Experimental Validation on a Flexible Fuel Engine2007-24-00359/16/2007
This paper describes the development of a computational thermodynamic model of compression, combustion and expansion processes of gasohol, ethanol and Natural Gas (NG) for the cylinder pressure curve prediction of a Flexible Fuel engine, working with a NG kit installed. The combustion process is modeled using a Wiebe function. Equations for specific heat at constant pressure (Cp) were developed for each fuel for temperatures up to 4000 K. The model output generates the cylinder gas pressure and temperature, work output and heat release profiles as functions of crank angle, allowing studies of engine performance parameters in different working conditions for each fuel. The differences between the experimental and simulation results were lower than 4% for the maximum cylinder pressure value.
Cordeiro de Melo, Tadeu Cavalcante, Machado, Guilherme Bastos, Machado, Renato Tristão, Pereira Belchior, Carlos Rodrigues, Pereira, Pedro Paulo
Optimization Performance of Multi-Fuel Spark Ignition Engine using a turbocharging system2006-01-264111/21/2006
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 gains obtained by this system in comparison with the traditional engine configuration are demonstrated in each stage of the experiment. With the results obtained we intend to create an alternative concept for a multi-fuel engine that allows for its optimization in such a way as to achieve the best possible performance with the use of either gasoline (E25), hydrated ethanol (E94) or vehicular methane gas (GMV).
Baêta, José Guilherme Coelho, Barros, José Eduardo Mautone, Valle, Ramon Molina, de Paula, Edmar Aderson Mendes
Analysis of Performance and Emissions of a Multi-fuel Vehicle2006-01-289611/21/2006
This paper presents the procedure and results of experimental tests performed with a multi-fuel (flex fuel) engine vehicle operating with gasoline, hydrated ethanol (AH), a mixture of the both fuels and, finally, with CNG. A comparison of the vehicle, operating in a chassis dynamometer and using these different fuels is described. It also shows the results of the tests performed with the vehicle after running 17500 km and 32750 km and the differences is presented.
Belchior, Carlos Rodrigues Pereira, Pinto, Nauberto, Pereira, Pedro Paulo
Spark Plugs for Multi-fuel Vehicles2006-01-263011/21/2006
Characteristics Multi-fuel vehicles demand great interest nowadays. This technology makes it possible for engine to work properly with any ethanol-gasoline mixture or Compressed Natural Gas (CNG). The preexisting spark plugs for either ethanol or gasoline engines have been created based on different functional requirements. On this context, to ensure a better performance in any mixed fuel-ratio and CNG high compression rate it was necessary to develop a spark plug taking into account the requirements for both cases simultaneously. The purpose of this paper is to enlighten the main technical spark plug features as enhanced thermal elasticity, improved ignition reliability through (Quick Heat™ design) and enhanced service life (less sooting, improved corrosion protection). These features provide considerable advantages for the multi-fuel system like improved idle stability, superior cold start and post-start performance, reduced CO (Carbon Monoxide) and HC (Hydrocarbonate) emissions making this spark plug as an environment-friendly product.
Bisetto, Fabiano, Toniolo, Juliano, Menezes, Ricardo
AEI 2006 Tech AwardsAUTOAPR06_114/1/2006
The editors of Automotive Engineering International highlight some of the more innovative new products and technologies on display at the SAE 2006 World Congress, based on the latest information provided by exhibiting companies. The TurboDISI engine from FEV is a 1.8-L turbocharged gasoline direct-injection engine that offers impressive low-end torque and a fuel economy typically associated only with diesel engines. The engine, which can replace larger, heavier naturally aspirated engines, also promises reduced emissions compared to naturally aspirated and port-fuel-injected turbocharged engines. Compared to the larger 2.6-L naturally aspirated engine that it replaces, the TurboDISI engine produces the same peak torque and power, but reaches peak torque more quickly while offering better specific fuel consumption throughout the engine map. It minimizes the traditional turbo-lag drawback experienced by conventional turbocharged engines, which is characterized by a delay in the torque rise during acceleration, and applies technologies such as variable valve timing, an integrated charge air cooler in the intake manifold, and advanced charge air devices.
MULTI-FUEL SPARK IGNITION ENGINE - OPTIMIZATION PERFORMANCE ANALYSIS2005-01-414511/22/2005
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. The previous methodology developed to adjust and calibrate the EMS in [2] was modified to allow gaseous fuel control. Before the adoption of turbocharging, it was necessary a careful study of the naturally aspirated version with different compression ratios to investigate how the compression ratio influences the engine performance for each fuel used. This paper discusses in details this investigation. Subsequent work with turbocharging is intended to be presented in future papers. All the results of the naturally aspirated engine This proposal can be used for some applications, giving the possibility to the automotive industry to utilize this engine system either to optimize the multi-fuel engines or to produce the same engine in the world for all types of gasoline for example, decreasing the cost of the production.
Baeta, José Guilherme Coelho, Amorim, Rogério Jorge, Valle, Ramon Molina, Barros, José Eduardo Mautone, de Carvalho, Remo Dias Bahia
SPARK IGNITION ENGINE PERFORMANCE USING SEVERAL ALCOHOL CONCENTRATIONS IN GASOLINE AND CNG2005-01-413811/22/2005
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.
Amorim, Rogério Jorge, Valle, Ramón Molina, Baeta, José Guilherme Coelho, Barros, José Eduardo Mautone, de Carvalho, Remo Dias Bahia
THE INFLUENCE OF DIFFERENT COMPRESSION RATIOS ON THE PERFORMANCE OF AN CNG-FUELLED FLEX INTERNAL COMBUSTION ENGINE2005-01-414111/22/2005
In Brazil, in the last few years, there has been a tendency to the use of alternative fuels. One of them is Compressed Natural Gas (CNG) and it is used due to its low cost, low fuel consumption and available technology. An originally gasoline or alcohol fuel engine can be also fuelled by CNG with some modifications, turning it into a multi-fuel engine. Commonly, however, the original compression ratio is unchanged, not allowing to explore CNG higher resistance to knock. This work aims at obtaining and analyzing the 1.3-L 8v FIRE FLEX engine performance curves for different compression ratios. A 5th generation BRC CNG multi-point fuel injection system is used for 11:1, 12,5:1 and 15:1 compression ratios and a development engine control unit and its calibration software were used to perform the system electronic management.
Amorim, Rogério Jorge, Valle, Ramón Molina, Baeta, José Guilherme Coelho, Barros, José Eduardo Mautone, de Carvalho, Remo Dias Bahia
The Volvo Heavy Truck Gas Turbine VT3002005-01-350411/1/2005
Renewed interest in a gas turbine as an alternative driveline for heavy trucks within Volvo, driven by the demands for lower emissions, resulted in a pre-study during 1990-1992 and the development and testing of a demonstrator engine between 1993 and 2000. To achieve the demanding goals for efficiency and emissions, the engine was designed as a recuperated and intercooled two shaft powerplant with a low-emission combustor. Following a comprehensive aerodynamic and concept study, engine components were rig tested and the engine mechanical design was finalized. Two engines were built and tested in a rig and in a truck. Very low exhaust emissions were demonstrated during rig testing, with NOx as low as 0,22 g/kWh in a 13-mode test. The efficiency goal of 42 % was not reached, but given more development time the measured efficiency of 38,6 % can most certainly be improved. Still, it will be the fuel consumption that is the major disadvantage compared to a diesel engine. The engine was also installed in a Volvo FH12 truck and tested for a limited time. The pros and cons of the gas turbines for trucks are discussed with some emphasis on emissions and fuel availability. Some areas where efforts must be made to improve the gas turbine are described and some suggestions of how to do it are given.
Olsson, Arne, Jönsson, Bertil, Sundin, Lars
Combustion and Emissions in a Spark-ignition Engine Fueled with Coal-Bed Gas - Modeling and Experimental Results2005-01-380410/24/2005
There is a worldwide interest in the research of various alternative fuels for automotive engines for the purpose of reduction of CO2 and toxically harmful exhaust emissions. Coal-bed gas, the main component of which is methane, has been considered an attractive alternative fuel for combustion engines due to its abundant resources, high hydrogen-carbon ratios and very low soot formation tendency. The composition of available coal-bed gas, however, can vary considerably, and this has made its combustion stability difficult to control in conventional spark ignition engines. To overcome the problem, a combustion system with a swirl chamber connected to the main combustion chamber through an orifice has been developed for the use of coal-bed gas in spark ignition engines, and the corresponding combustion process has been studied using a developed combustion model involving flame kernel formation and flame front propagation. The combustion model includes two sub-models with the first dealing with the calculation of turbulence intensity history, and the second modeling a jet flow through the orifice of the swirl chamber. Emissions of NOX, HC and CO have been predicted using the combustion model based on an extended Zeldovich mechanism, wall quenching and incomplete oxidation simulations. The effects of various components in coal-bed gas on the engine combustion process and emissions are also investigated. Validation of the combustion model has been performed through comparing simulation data with the experimental result obtained from a relevant single cylinder research engine, and a satisfactory agreement between them has been achieved in terms of combustion parameters and exhaust emissions.
Qian, Yejian, Zuo, Chengji, Tan, Jian, Xu, Hongming
The Application of Air-Assist Direct Injection for Spark-ignited Heavy Fuel 2-Stroke and 4-Stroke Engines2005-32-006510/12/2005
There is a growing requirement for lightweight high performance engines capable of operation with heavy fuels such as JP5 (F44), JP8 (F34) and diesel fuels as well as maintaining the capability of running on unleaded gasoline. Traditionally heavy fuels are associated with operation in compression ignition engines which exhibit poor power to weight characteristics. Today's engine applications call for much greater mobility and flexibility in use, especially in applications such as outboard engines, motorcycles, All Terrain Vehicles, Light Aircraft and portable generator sets. Compression ignition engines with their poor power to weight and vibration characteristics are less likely to succeed in these applications. These requirements are more likely to be met by the development of a spark ignition engine capable of operating on these heavy fuels. With the development of Direct Injection technologies it is now possible to achieve sufficient control over the combustion process in spark ignition engines to overcome the poor physical properties of the heavy fuels that to date have prevented good combustion being achieved across the entire speed and load domain of the engine. This paper explores the development path and results from several conversions of direct injected gasoline engines, both 2 and 4-stroke, to operate as spark ignition heavy fuel engines, thus offering the fuel of choice whilst retaining the weight advantages and the desirable power to weight ratios of the gasoline engines.
CATHCART, Geoffrey, DICKSON, Gavin, AHERN, Steven
Experimental Analyses of Flexible Fuel Systems in Spark Ignition Engine2005-01-21835/11/2005
This work presents an analysis of the performance of a multi-fuel engine fuelled by gasoline, alcohol, a mixture of gasoline and alcohol and CNG. The tests are made using 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. In order to run with CNG, it was installed a BRC 5th generation multi-point fuel injection system. The calibration and adjustments were made using a development engine control unit for the different fuels. In this work, the performance curves are compared aiming to obtain the best relation among torque, power and specific fuel consumption for the various proposed configurations.
Amorim, Rogério Jorge, Baeta, José Guilherme Coelho, Valle, Ramón Molina, Barros, José Eduardo Mautone, de Carvalho, Remo Dias Bahia
A New Concept of a Flex Multi-Fuel Engine2004-01-342711/16/2004
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. With this work we intend to create an alternative optimizing concept for the 1.3 8v FIRE FLEX MULTI-FUEL engine to allow it to attain peak efficiency when one of the following types of fuel is used: Gasoline E25, E94 ethyl hydrate, any level of mixed Gasoline E25 and Alcohol E94, and CNG.
Baeta, José Guilherme Coelho, Valle, Ramón Molina, Barros, José Eduardo Mautone, Amorim, Rogério Jorge, de Deus, José Renato Barbosa, de Carvalho, Remo Dias Bahia
Future General Aviation Piston Engines and Fuels - An Integrated Approach2004-01-18104/20/2004
The continued availability of leaded specialty aviation gasolines remains as an item of crucial importance in the near-term future of general aviation; however, the development of new piston engines capable of operation with other transportation fuels available in large pools is considered an indispensable element in the long-range survival of the industry. This paper offers a road map that while allowing the continued utilization of the current fleet of piston aircraft, sets the stage for a transition to new piston powerplants and associated aircraft, compatible with widely available transportation fuels such as motor gasoline based aviation fuels for the lower and some medium performance aircraft, and aviation turbine fuels for the balance of medium and high performance airplanes. The proposed fuels and associated aircraft engines transition road map represents an integrated approach that covers the entire family of future general aviation products, in contrast with current fragmented efforts that ignore the small volume and wide world dispersal of this market. Transportation fuels likely to remain available around the world well into the future, determine the characteristics and combustion technologies of future engines. A discussion of said engine technologies, including emerging new combustion concepts, power management and advanced essential engine accessory systems is included in this document. This paper reflects generalized results of extensive studies and related supportive research activities on current typical general aviation fuels and engines, and on fuels and experimental engines envisioned to support the industry during the next 50 years.
Gonzalez, Cesar, Jesik, Richard L.
Percent Ethanol Estimation on Sensorless Multi-Fuel Systems; Advantages and Limitations2003-01-356211/18/2003
Ethanol is a widely used automotive fuel alternative. To improve it's market acceptance multiple fuel capability is important. Engine management systems were recently introduced that reduce the add-on cost of multiple fuel capability by deleting the ethanol sensor and work with exhaust oxygen sensor feedback to estimate the Ethanol content in the fuel. These systems show a %Ethanol estimation accuracy of better than 4% over the entire %Ethanol range with nominal components. If stacked-up production tolerances of all components are considered this estimation accuracy is significantly worse introducing some undesirable side effects on fuel and spark delivery. Special care has to be taken in calibration, or specific engine management algorithms should be introduced, to minimize the impact of these side effects. In order to optimize performance on all percentages of Ethanol an adaptive knock control system as part of the engine management system should be used. For the Brazilian situation, that has E20 and E100 commercially available, system performance can be improved by limiting the learn range at the low side to E20.
Theunissen, Frans M. M.
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