Search

This study compared the fuel consumption and exhaust emissions of a sparkignition engine using a carburetor fuel system, an injection fuel system, and an ultrasonic fuel system. When using gasoline only, the ultrasonic fuel system showed a 31% decrease in fuel consumption compared to the carburetor system and a 15% decrease compared to the injection system. When adding 10% bioethanol to the gasoline, fuel consumption increased in all three systems, with the ultrasonic system showing the largest increase of 10%. Exhaust emissions were also measured, and the ultrasonic system showed a significant decrease in CO, HC, and NOx compared to the carburetor and injection systems, with the largest decrease in CO emissions. The addition of bioethanol to the fuel resulted in reducing exhaust emission values in all three systems, with the ultrasonic system showing the largest decrease in CO and HC emissions compared to the carburetor and injection systems, but with an increase in NOx emissions compared to the injection system. When comparing three fuel systems, it was observed that injection fuel systems have the highest CO2 values. Although the addition of alcohol to the fuel does not cause a significant change in CO2 emission values for injection and ultrasonic fuel systems, an increase is observed in the carburetor fuel system. Overall, the ultrasonic fuel system showed promising results for reducing fuel consumption and improving exhaust emissions. [ABSTRACT FROM AUTHOR]

A new fuel injection system with a solenoid actuator was developed to reduce jet stabilization times and was compared to a conventional fuel injection system using a fast-acting valve. The jet stabilization time was examined from free-jet images obtained using a flow visualization technique. Using a supersonic wind tunnel, the jet establishment image and trajectory for supersonic flows were obtained. The jet stabilization times were obtained at fuel tank pressures of 500, 700, and 900 kPa and injection orifice diameters of 1 and 2 mm. For all cases, the jets were stabilized at 4–12 ms, which was shorter than the stabilization time (approximately 300 ms) of the conventional system. The injection pressure measurements and jet trajectory comparison showed that the new system could inject fuel at the target pressure more effectively than the conventional fuel system. [ABSTRACT FROM AUTHOR]

Marine electronically controlled (ME) two-stroke diesel engines occupy the highest market share in newly-built ships and its fuel injection system is quite different and important. Fault diagnosis in the fuel injection system is crucial to ensure the power, economy and emission of ME diesel engines, so we introduce hierarchical multiscale fluctuation dispersion entropy (HMFDE) and a support matrix machine (SMM) to realise it. We also discuss the influence of parameter changes on the entropy calculation’s accuracy and efficiency. The system simulation model is established and verified by Amesim software, and then HMFDE is used to extract a matrix from the features of a high pressure signal in a common rail pipe, under four working conditions. Compared with vectorised HMFDE, the accuracy of fault diagnosis using SMM is nearly 3% higher than that using a support vector machine (SVM). Experiments also show that the proposed method is more accurate and stable when compared with hierarchical multiscale dispersion entropy (HMDE), hierarchical dispersion entropy (HDE), multiscale fluctuation dispersion entropy (MFDE), multiscale dispersion entropy (MDE) and multiscale sample entropy (MSE). Therefore, the proposed method is more suitable for the modelling data. This research provides a new direction for matrix learning applications in fault diagnosis in marine two-stroke diesel engines.

Although direct measurements of the fuel injection pressure and the travel of the injector needle in conjunction with measurements of the valve train mechanism timing can provide complete diagnostic information about the technical conditions of the fuel injection and valve train systems, this requires the installation of sensors and other equipment directly into the systems, which is possible within research laboratories but is generally forbidden during operation of the ship. Malfunctions in the fuel injection and valve train systems can also be identified from the indicator diagrams of an engine operating cycle, expressed as P(V) and P(deg) diagrams. The basic parameters of the engine operating cycle, such as the maximum combustion pressure Pmax, compression pressure Pcompr, and indicated mean effective pressure IMEP, can also be used to indicate deviations from proper engine operation. Using a combination of a vibration sensor with an in-cylinder gas pressure sensor widens the capabilities of diagnostics for marine diesel engines under operational conditions. A vibration sensor with a magnetic base can help in determining the timings of the lifting and landing of the injector needle, fuel delivery by the fuel injection pump, opening and closing of the circulation of heated heavy fuel oil, and opening and closing of the gas distribution valves. This also offers a promising solution for diagnostics of the cylinder lubrication oil injectors. The proposed approach allows valuable information to be received during engine operation in accordance with the principle of non-destructive control, and can help in early detection of possible engine malfunctions.

Highlights: Compared with discharge valve chamber volume, high-pressure tubing diameter shows more influence on injection mass and SMD. The opening pressure of needle valve is more sensitive to SMD. An overall simultaneous reduction of pollutant emissions was obtained, alleviating the trade-off relations between NO and soot emissions. Reasonable optimization of spray angle can improve power, economy and emission performance simultaneously. The emission requirements of diesel engines are becoming increasingly strict and reducing emissions has become the key technology. In view of this development trend, the influence law of fuel injection on emission is studied in this paper. Numerical studies were performed to analyze the structural parameters of fuel injection system on combustion and emission characteristics of marine diesel engines. The numerical modelling was validated based on single-cylinder diesel engine tests and fuel injection tests. After investigating the single structural parameters on the fuel injection characteristics, the orthogonal method was used to design the double-parameter structural optimization scheme of the fuel injection system. There are 22 optimized cases selected to further investigate using the CFD method by visualizing scalar distributions in cylinder, which was helpful to explain the reason of pollutant formation. Comprehensively comparing the performance of each fuel injection system's structural optimization scheme, moderate reduction of the discharge valve chamber volume and high-pressure tubing diameter would increase injection mass, along with faster injection rate and boosted injection pressure, leading to reduced Sauter mean diameter (SMD). Considering pollutant emission characteristics as well as economic and power concerns, case D6 with spray angle enlarging 5° showed best performance. Compared with the original condition, there was no NO deterioration and large reduction of soot emission by 65.4%, along with fuel consumption being lowered by 2.18% and more indicated power, by 2.21%. Therefore, reasonable optimization of spray angle can improve power, economy and emission performance simultaneously. [ABSTRACT FROM AUTHOR]

Motorcycles are popular vehicles in Vietnam, and their numbers are increasing. According to forecasts, there will be about 75 million in circulation by 2025, which is the year Vietnam will start implementing exhaust gas testing for motorcycles by Vietnamese National Standards "TCVN 643:2018". This is the maximum permitted limit of exhaust gases for road vehicles in Vietnam. It is difficult for older motorcycles to meet this requirement, so alternative fuels need to be considered. LPG has the advantage of being a clean fuel in abundant supply, and so has the potential to provide a solution. This study was conducted on an old motorcycle of a type that is very common in Vietnam. A bi-fuel LPG and gasoline system was built from the fuel injection system on the motorcycle, with only the need to calculate, design and install two additional injectors for the LPG. The engine was run on a test platform using GT-POWER simulation software, which optimized the primary ignition angle for the LPG. The performance and pollution data were compared between gasoline and LPG, both by experiment and simulation. The results show that the performance of the LPG declines. However, the exhaust emission and fuel economy improve. The system studied does not require a change to the fuel injection system or the engine, manufacturing costs are low, and it is easy to apply in the actual situation of motorcycles in Vietnam today. • A bi-fuel LPG and gasoline system was built from the fuel injection system on the motorcycle. • The system studied does not require a change to the fuel injection system or the engine. • The ignition angle of the engine when using LPG is analyzed and selected by simulation determined to be 25°. • The results show that the performance of the LPG declines. However, the exhaust emission and fuel economy improve. [ABSTRACT FROM AUTHOR]

In this study, two different 55-kW powered agricultural tractors of the same make and model were operated for 1000 h under similar field conditions, one using diesel fuel (DF) and the other a fuel blend of 20% biodiesel-80% diesel (B20). By the end of 1000 h of operation, the performance values of the B20 fuel were determined to be 3% lower than for the DF. Although the values of CO (40%), HC (40%), and PM (46%) were lower than those of DF, the NOx (7%) was determined to be higher, as expected. Each injector needle and nozzle tip was examined in terms of a functional evaluation via visual inspection, scanning electron microscopy (SEM), and energy dispersive X-ray (EDX). According to the analyses, the B20 fuel blend C content was determined to be 73.47% and its O content 23.34%, with the quantity of the other elements lower than 1%. Similarly, for DF, the C content was determined to be 50.49% and that of O 19.95%, with the other elements in trace amounts. Furthermore, Fourier-transform infrared spectroscopy (FTIR) spectral analysis was used to examine the deposits on the injector nozzle tips and needles. Polyisobutylene succinimide (PIBSI) and inorganic components were observed on the injector needles, whereas aging products and inorganic components were seen on the injector nozzle tips. No significant difference was found between the results of the DF and B20 fuels in terms of injector nozzle function. [ABSTRACT FROM AUTHOR]

Diesel engine has widely been used in the non-road mobile machinery industry, because of its considerable advantages in power, economy, and reliability. However, the working process of an diesel engine is rough, due mainly to the compression ignition operating mode Furthermore, the noise of the diesel engine cannot meet the requirements of living comfort. Therefore, it is highly necessary to reduce the noise of diesel engines. The noise of the internal combustion engine mainly includes aerodynamic, mechanical, and combustion noise. Combustion noise plays a leading role in the total noise of diesel engines, especially for direct injection diesel engines. Combustion noise is also closely related to the combustion process of internal combustion engines. The combustion noise is greater, as the combustion process is more intense in recent years. Fortunately, the noise can be reduced via the optimized parameters and tunable process. Therefore, the in-cylinder combustion process can also be optimized for the noise reduction of diesel engines. Since the pre-injection, exhaust gas recirculation (EGR), and turbocharging technologies cannot be widely used to reduce combustion noise for low power non-road diesel engines, due to the cost, structure, and application object. Therefore, the reasonable selection of parameters can make the matching of "fuel, air, and chamber" more perfect on the basis of existing low-power non-road diesel engine parts, thereby improving the combustion process in the cylinder. In this study, an optimization experiment was performed on the in-cylinder combustion of a diesel engine, in order to ensure the power performance, economy, NOx, and soot emissions of low power non-road machinery, while reducing the combustion noise in the diesel engine. A low-power non-road 4D29G31 diesel engine was used as an original engine. The optimization was made on the nozzle protrusion, nozzle hole number, nozzle hole diameter, and swirl ratio. The “fuel, air, and chamber” achieved the best matching state to improve the fuel-air mixing, the combustion in cylinder, and performance of diesel engine. The dynamic fuel supply advance angle was optimized to shorter the ignition delay time. The combustion rate and pressure oscillations were then be suppressed during the rapid combustion period. The maximum combustion pressure and the rising rate of the diesel engine under the rated condition were reduced by 18% and 44.9% after optimization, respectively, where the noise of the engine was reduced by 0.73 dB, compared with the original engine. The maximum combustion pressure and the rising rate of the diesel engine were reduced by 39% and 40% under the maximum torque condition, respectively, where the noise of the engine was reduced by 1.07 dB than before. It demonstrated that the combustion noise was reduced significantly in the whole diesel engine after optimization. At the same time, the economy and emission performance of diesel engines reached optimal in a low-power non-road diesel engine. [ABSTRACT FROM AUTHOR]

The emission requirements of diesel engines are becoming increasingly strict and reducing emissions has become the key technology. In view of this development trend, the influence law of fuel injection on emission is studied in this paper. Numerical studies were performed to analyze the structural parameters of fuel injection system on combustion and emission characteristics of marine diesel engines. The numerical modelling was validated based on single-cylinder diesel engine tests and fuel injection tests. After investigating the single structural parameters on the fuel injection characteristics, the orthogonal method was used to design the double-parameter structural optimization scheme of the fuel injection system. There are 22 optimized cases selected to further investigate using the CFD method by visualizing scalar distributions in cylinder, which was helpful to explain the reason of pollutant formation. Comprehensively comparing the performance of each fuel injection system’s structural optimization scheme, moderate reduction of the discharge valve chamber volume and high-pressure tubing diameter would increase injection mass, along with faster injection rate and boosted injection pressure, leading to reduced Sauter mean diameter (SMD). Considering pollutant emission characteristics as well as economic and power concerns, case D6 with spray angle enlarging 5° showed best performance. Compared with the original condition, there was no NO deterioration and large reduction of soot emission by 65.4%, along with fuel consumption being lowered by 2.18% and more indicated power, by 2.21%. Therefore, reasonable optimization of spray angle can improve power, economy and emission performance simultaneously.

Samples of unadditised, middle distillate diesel fuel were injected through real-size optically accessible mini-sac diesel injectors into ambient air at common rail pressures of 250 and 350 bar, respectively. High-resolution images of white light scattered from the internal mini-sac and nozzle flow were captured on a high-speed monochrome video camera. Following the end of each injection, the momentum-driven evacuation of fuel liquid from the mini-sac and nozzle holes resulted in the formation of a vapour cloud and bubbles in the mini-sac, and vapour capsules in the nozzle holes. This permitted external gas to gain entrance to the nozzle holes. The diesel fuel in the mini-sac was observed to rotate with large initial vorticity, which decayed until the fuel became stationary. The diesel fuel remaining in the nozzle holes was observed to move inwards towards the mini-sac or outwards towards the nozzle exit in concert with the rotational flow in the mini-sac. The mini-sac bubbles’ internal pressure differences revealed that the bubbles must have contained previously dissolved oxygen and nitrogen. Under diesel engine operating conditions, this multi-phase mixture would be highly reactive and could initiate local pyrolysis and/or oxidation reactions. Finally, the dynamical behaviour of the diesel fuel in the nozzle holes would support the admission of external hot combustion gases into the nozzle holes, establishing the conditions for oxidation/pyrolysis reactions with surrounding liquid fuel films. [ABSTRACT FROM AUTHOR]

Regimes of continuous detonation of CH4/H2–air mixtures with mass fractions of H2 in the fuel equal to 0–1/5 are obtained in an annular combustor 503 mm in diameter with variation of the combustor geometry. The influence of the combustor geometry on the velocity and number of transverse detonation waves, pressure in the combustor, and specific impulse is considered. It is found that three-fold constriction of the combustor exit cross area allows obtaining two-wave regimes of continuous spin detonation in the pure methane–air mixture. Based on stagnation pressures measured at the combustor exit, the specific impulses in the case of continuous detonation are determined for different compositions of the fuel. [ABSTRACT FROM AUTHOR]

The fuel injection system is one of the key components of an in-cylinder direct injection engine. Its performance directly affects the economy, power and emission of the engine. Previous research found that the Taguchi method can be used to optimize the fuel injection map and operation parameters of the injection system. The electronic control injector was able to steadily control the operation performance of a high-pressure fuel injection system, but its control was not accurate enough. This paper conducts an experimental analysis for the fuel injection quantity of DI injectors using the Taguchi-Regression approach, and provides a decision-making analysis to improve the design of electronic elements for the driving circuit. In order to develop a more stable and energy-saving driver, a functional experiment was carried out. The hybrid Taguchi-regression algorithm for injection quantity of a direct injection injector was examined to verify the feasibility of the proposed algorithm. This paper also introduces the development of a high-pressure fuel injection system and provides a new theoretical basis for optimizing the performance of an in-cylinder gasoline direct injection engine. Finally, a simulation study for the fuel injection control system was carried out under the environment of MATLAB/Simulink to validate the theoretical concepts.

The aim of the paper is to highlight, if not all, then at least the most important benefits of the application of mathematical modeling in the development of a new solution or in the process of improvement and the optimization of an existing product. The thesis presents the basic principles of the model creation without providing a detailed mathematical interpretation of the process; therefore, the model includes a substantial number of unknown or approximately known parameters and it is not possible to create a model of the transparent cybernetic box type. In order to achieve a synthesis of the model and the experimental results, it is necessary to apply the optimization methods for the identification of unknown model parameters. The thesis presents the experimental results along with the results of modeling and identification as well as the analysis of the process of identification of unknown model parameters. / Целью работы является подчеркивание преимуществ при применении математического моделирования в проектировании и разработке новых решений или оптимизации существующего объекта. Представлены основные принципы моделирования без изложения подробной математической модели, из чего следует, что модель включает в себя множество неизвестных или приблизительно известных параметров, соответственно модель прозрачного кибернетического ящика исключается. Для того чтобы достичь синтеза моделей и экспериментальных результатов необходимо применение методов оптимизации для идентификации неизвестных параметров модели. В статье представлены экспериментальные результаты наряду с результатами моделирования, а также анализ результатов процесса идентификации неизвестных параметров модели. / Cilj rada je da se istaknu, ako ne sve, a ono bar najvažnije prednosti koje donosi primena matematičkog modeliranja tokom projektovanja novog rešenja ili usavršavanja i optimizacije postojećeg objekta. Izloženi su osnovni principi izrade modela bez iznošenja detaljne matematičke interpretacije procesa iz čega sledi da model sadrži veći broj nepoznatih ili orjentaciono poznatih parametara i da nije moguće realizovati model tipa prozirne kibernetičke kutije. Da bi se ostvarila sinteza modela i eksperimentalnih rezultata neophodna je primena optimizacionih metoda za identifikaciju nepoznatih parametara modela. U radu su navedeni eksperimentalni rezultati uporedo sa rezultatima modeliranja i identifikacije kao i analiza postupka identifikacije nepoznatih parametara modela.

Highlights • An innovative closed-loop control strategy of the injected mass has been developed. • The strategy has been implemented in rapid prototyping hardware. • The performance of the new injection system has been compared with that of a standard CR. • The potential of the strategy to reduce CO 2 , CN and pollutants has been assessed. Abstract A closed-loop strategy that is capable of controlling the fuel injected mass in the combustion chamber of a Common Rail diesel engine has been set up. The pressure time histories measured along the rail-to-injector pipe have been used to evaluate the instantaneous mass flow-rate entering the injector. This flow-rate has then been integrated between two time instants, and the thus calculated fuel mass has resulted to correlate well with the injected mass. A rapid prototyping hardware has been realized to control the rail pressure and the injected mass through feedback strategies. Steady state and dynamic tests on the prototypal injection system have been carried out on a hydraulic rig. The innovative injection apparatus, which features the closed-loop control of the injected mass, can significantly improve the injected mass accuracy for the different thermal regimes, compared to a state-of-the-art Common Rail system. The error in the actuated injected mass was found to be below 1 mg for all the working conditions and the sensitivity of the injection performance to fuel temperature was significantly reduced. Furthermore, the dynamic response of the new injection system to either step or ramp transients in the rail pressure and in the injected mass was also enhanced appreciably. This has allowed the calibration maps to be followed more precisely during the engine transients. Preliminary simulation tests, performed with a 1D code on a diesel engine for light duty commercial vehicles, have proved that the new technology could lead to important reductions in the CO 2 engine out emissions (3%) and in the combustion noise (up to 0.5 dBA). Significant percentage improvements in NO x (3%) and soot (6%) engine out emissions have also been found. [ABSTRACT FROM AUTHOR]

Highlights • The benefits of digital and continuous injection rate shaping schedules are shown. • A new closed-loop control strategy of the injected mass has been developed for multiple injections. • The new control has been implemented in a prototypal hardware and hydraulic tests have been carried out. Abstract The results of digital and continuous rate shaping strategies are discussed for a low temperature combustion diesel engine. The outcomes show a high potential of these injection schedules for the management of the trade-off between engine out emissions, fuel consumption and combustion noise. However, a weak point has emerged concerning the high value of the coefficient of variation of the indicated mean effective pressure. This is due to instability of the mass that is injected in a multiple injection when the injection shots are closely coupled. An innovative closed-loop control strategy of the injected mass is developed for multiple injections. Pressure time histories, measured along the rail-to-injector pipe, are used to infer the instantaneous mass flow-rate entering the injector. This flow-rate is integrated between two optimized time instants and the thus calculated fuel mass results to correlate well with the injected mass. The new control strategy has been implemented in rapid prototyping hardware and tests have been performed at the hydraulic rig. The prototypal fuel injection system controls the injected mass with an accuracy of 2 mg over the entire dwell time range. A significant improvement has been observed, compared to state-of-the-art injection systems, in the stability of the injected mass for the closely coupled injections. [ABSTRACT FROM AUTHOR]

Regimes of continuous detonation of methane/hydrogen-air mixtures in spin and opposing transverse detonation waves are obtained for the first time in a flow-type annular cylindrical combustor 503 mm in diameter. A two-component (methane/hydrogen) fuel with the H2 mass fractions of 1/9 to 1/2 in the range of specific flow rates of the mixture from 64 to 1310 kg/(s ·m2) and the fuel-to-air equivalence ratio ϕ = 0.78-1.56 is considered. In methane/hydrogen-air mixtures with two compositions of the fuel (CH4 + 8H2 and CH4 + 4H2), one-wave and two-wave regimes of continuous spin detonation are obtained; the frequency of rotation of transverse detonation waves is 0.56-1.66 kHz at ϕ = 0.78-1.02. For the fuel compositions CH4 + 2H2 and CH4 + 1.5H2, continuous multifront detonation with two opposing transverse detonation waves rotating with the frequency of 0.86-1.34 kHz at ϕ = 1.0-1.23 is obtained. For the CH4 + H2 + air mixture, both combustion in the chamber and continuous spin detonation outside the combustor with transverse detonation waves rotating with the frequency of 1.01-1.1 kHz are observed. The lean limits of continuous detonation are obtained in terms of the specific flow rate of the mixture: 64, 100, 200, and 790 kg/(s · m2) for the fuel compositions CH4 + 8H2, CH4 + 4H2, CH4 + 2H2, and CH4 + 1.5H2, respectively, for the mass fraction of hydrogen in the methane/hydrogen fuel of ≈0.16. Violation of regularity of the continuous detonation wave structure and the wave velocity with a decrease in the fraction of hydrogen in the two-component fuel is detected. [ABSTRACT FROM AUTHOR]

In this scientific paper, am approach based on Engine Digital Scanning (EDS) was applied in order to underline the performances of more than ten engine speed regimes on the same rally car, but with various intake manifold pressures, fuel injection duties and ignition advances. A specific study of trend lines and parameter variation was developed to highlight internal combustion engine's (ICE) operational indicators and to define the optimal regime with increased intake pressure, improved combustion and lower pollution influencing conditions. Manifold pressure dictates the base condition for air-fuel mixture formation and for lambda value before engine intake process in the case of port fuel injection (PFI). Fuel injection duty expresses the operational sequence time in relation with a base parameter in the engine working process. Ignition advance is adapted to the hydraulic-fuel charge, as well as engine load and speed so it is analysed. [ABSTRACT FROM AUTHOR]

As society and economy developing, the problem caused by non-road diesel engine emission has been widely drawing people’s attention. Increasingly serious environmental problems have forced people to use advanced technology to reduce engine emissions and lots of countries have established non-road diesel engine emission regulations. Developed countries, represented by the United States of America and the European Union, have formulated stringent emission regulations to limit emissions from non-road diesel engines. China issued the limits and measurement methods for exhaust pollutants from diesel engines of non-road mobile machinery in 2014. By using the vehicle emission control technology, the high power (>37 kW) diesel engine could meet the emission standards. Because of the structure, production costs and application limit, electronic control system, common rail system, turbocharger, exhaust gas recirculation and selective catalytic reduction can’t be applied in low power (<37 kW) non-road diesel engine. So there are a lot of technical difficulties for the upgrade of low power non-road diesel engine emissions. In addition, the strict regulations on the brake specific fuel consumption (BSFC) of diesel engines were made, which further increases the difficulty of such diesel engine emissions meeting the requirements. The emission standards implementation and requirements of the low power non-road diesel engine are constantly tightened. The electronically controlled VE pump-line-nozzle fuel injection system has the advantages of low cost, simple structure, convenient arrangement on the engine, and also has the potential to meet Level III or even Level IV emission regulation requirements in China. Therefore, it’s necessary to research and develop a low power non-road diesel engine with high performances and low emissions. In this article, the non-road N490 direct injection diesel engine was taken as the prototype, By using a combination of theoretical analysis and experimental research, technology strategy of low non-road diesel engines was explored to meet the requirements of high performance and low emissions. By increasing the pump cam lift, reducing the inner diameter of the high-pressure fuel pipe, and improving nozzle geometry of the injector, the maximum nozzle side pressures at the rated condition and the maximum torque condition increased by 32.7% and 50%, respectively. Re-entrant dumbbell-shaped chamber was designed to strengthen the central bulge of the combustion chamber bottom, which improved the air movement in the combustion chamber. By adjusting the valve timing, the volumetric efficiency of the diesel engine was improved. The combustion was optimized by reducing the fuel injection quantity during ignition delay period. After optimizing the parameters of the fuel injection system, the valve timing and combustion chamber, the diesel engine performance was greatly improved. Compared with the original engine, both at the rated condition and at the maximum torque condition, the specific fuel consumption was decreased by 3.0% and 2.43%, respectively, and the light-proof smoke was also decreased by 14.6% and 10%, respectively. The experimental results showed that the exhaust emissions of carbon monoxide (CO), nitrogen oxide (NOx) + hydrocarbon (HC), and particulate matter (PM) were 1.109, 6.23 and 0.522 g/(kW·h), respectively, which were lower than Level emission standards in China. Compared with the results of the prototype, the measured values of CO, NOx+HC and PM were reduced by 34.7%, 21.5% and 34.9%, respectively. At the same time, both the maximum cylinder pressure and the heat release rate were greatly reduced. At the rated and the maximum torque conditions, the maximum cylinder pressures were decreased by 15.8% and 9.6%, respectively; the maximum heat release rates were decreased by 9% and 8.8%, respectively. Through the analysis of experimental data, the research shows that optimization matching of fuel injection, in-cylinder air movement and combustion chamber can not only decrease the exhaust emissions obviously but improve the fuel economy of the engine. [ABSTRACT FROM AUTHOR]

The introduction of new vehicles technology has been projected for advanced technologically places. Their use and operation, is a theme of big concern for developing countries. This work is part of the study for the creation and establishment of a maintenance strategy and policy, which will be acceptable in developing countries. The paper proposes a methodology for the identification of critical components of the electronic fuel injection system with failure mode, effects and criticality analysis tool (FMECA). With the elaboration of this work, was possible to visualize that the maintenance strategy for each component depends strongly on the availability of equipment for the diagnosis (fail detection). As future work, would be important to study the influence of others parameters that influence the maintenance and vehicle operation, as cost, environment, human aspect and vehicle operation. Another useful analyses would be, to analyses the data in a probabilistic interpretation in order to visualize influence of each component failure in the system failure. [ABSTRACT FROM AUTHOR]

The aim of the paper is to highlight, if not all, then at least the most important benefits of the application of mathematical modeling in the development of a new solution or in the process of improvement and the optimization of an existing product. The thesis presents the basic principles of the model creation without providing a detailed mathematical interpretation of the process; therefore, the model includes a substantial number of unknown or approximately known parameters and it is not possible to create a model of the transparent cybernetic box type. In order to achieve a synthesis of the model and the experimental results, it is necessary to apply the optimization methods for the identification of unknown model parameters. The thesis presents the experimental results along with the results of modeling and identification as well as the analysis of the process of identification of unknown model parameters. [ABSTRACT FROM AUTHOR]

Multiwave regimes of continuous spin detonation in syngas-air mixtures in a flow-type annular cylindrical combustor 503 mm in diameter are obtained. Experiments are performed for mixtures of carbon oxide and hydrogen with the ratio of the components equal to 1/3, 1/2, or 1/1. The varied parameters are the flow rates of air and syngas, the ratio of these flow rates, and the combustor length. Scalability of the continuous spin detonation process is demonstrated: at identical values of the specific flow rate of air and the combustor expansion ratio, the number of transverse detonation waves increases with increasing combustor diameter. In the examined ranges of combustor lengths and specific flow rates of air, the frequency of these waves is independent of the combustor length, except for narrow regions where the number of waves (and, correspondingly, the flow regime) changes. The structures of transverse detonation waves in regular regimes are almost identical for all examined syngas compositions. It is shown that detonation can be initiated by a jet of combustion products. The minimum diameters of the detonation chamber for different flow rates of the mixture are estimated. [ABSTRACT FROM AUTHOR]

The pilot injected fuel masses generally are in the 1–4 mg range for automotive diesel engines and are affected by significant dispersion, which represents an issue for injection control systems. A new methodology has been developed for real-time evaluation of the fuel injected in small injections in diesel engines. The measurement requires the installation of a single pressure transducer on a pipe connecting the injector to the rail. A simple algorithm, which is based on the mass conservation and momentum balance equations, written with respect to a reference frame that is integral with the pressure wave front, has been elaborated to convert the experimental pressure time history into an instantaneous flow rate. The results on the flow-rate through the pipe that connects the injector to the rail are compared with the corresponding numerical outcomes from a 1D model of the fuel injection system. The estimated fuel quantities that enter the injector have been verified to be well correlated with the measured volumes of the fuel injected in small injections. The relation that has been found could be implemented in the engine electronic control unit and employed together with the pressure transducer installed at the inlet of the injector for a more accurate real-time control of both the injected mass and the system high-pressure. [ABSTRACT FROM AUTHOR]

A fully predictive model of a Common Rail fuel injection apparatus, which includes a detailed simulation of rail, pump, piping system, injectors and rail pressure control system, is presented and discussed. The high-pressure pump and injector sub-models have been validated separately and then coupled to the rail and pressure control system sub-models. The complete predictive model has been validated and applied to investigate the effects of the dynamics of each component of the injection apparatus on the rail pressure time history. Variable timing of the high-pressure pump delivery phases has also been considered, and the influence of this parameter on the injection performance has been analysed for both single- and multiple-injection events. Furthermore, the injection system dynamics during the transients between steady-state working conditions has been investigated in order to highlight the role played by the dynamic response of the pressure control system on the rail pressure time history. [ABSTRACT FROM AUTHOR]

On basis of analysis of various methods of hydrogen feeding for automotive engine supply methods of multipoint hydrogen distribution with microprocessor-based control are proposed.

Formation of surface carbonaceous deposits at inner surface of two classes of simulated jet engine burner feed arm including a straight tube as well as two tubes with sudden expansion/contraction was studied using “Aviation Fuel Thermal Stability Test Unit (AFTSTU)”. The generated results indicate that phenomena such as stagnant flow formation, flow separation and vena contracta have a substantial impact on surface deposition. Commercial “Computational Fluid Dynamics (CFD)” package, ANSYS Fluent was used to interpret the impact of flow features and heat transfer characteristics on surface deposition. The experimental data obtained in this work were used in a one dimensional heat transfer model for prediction of deposit thickness in simulated burner feed arms. Subsequently, the simulated burner feed arm with contraction/expansion structure were sectioned and prepared for deposit visualisation with “Scanning Electron Microscopy (SEM)”. The results of visualised deposits are consistent with one dimensional heat transfer calculation. The novel set of experimental data presented in this work provides a basis for the construction of predictive models for calculation of deposit growth and total deposit mass in fuel injection system. A description of the model will be addressed in the second paper of this work which is currently under preparation. [ABSTRACT FROM AUTHOR]

The huge annual output of single-cylinder diesel engines is a major feature of Chinese internal combustion engine industry. In China the amount of these engines with bore diameter below 80 mm accounts for 35% of domestic production. Most of these diesel engines adopt the swirl chamber combustion system. However, with the development of direct-injection process, many problems for these engines occur, such as large smoke emissions at full load, poor performance under low speed and high idle speed, and there are few basic researches on them. Therefore, the research of low-emission high-performance swirl chamber diesel engines contains certain academic significance and practical value. The 170F swirl chamber diesel engine was used as the research prototype, and with the method of experiment and numerical simulation, the fuel injection and combustion systems were analyzed. By the design of new injector, the establishment of simulation model of injection system and the optimization of the injection parameters, the maximum fuel pressure under the rated conditions increased from 18.54 to 25.28 MPa, the initial injection rate reduced and the shape of injection rate was optimized. By the simulation of combustion with the software FIRE, the deviate distance from the injection oil line to the center of the swirl chamber and the best volume ratio were determined. The results showed that when the deviate distance from the injection oil line to the center of the swirl chamber was at 0.33-0.38 R (R is the radius of the swirl chamber), and the volume ratio was in the range of 0.47-0.50, the mixing and combustion performance would be better. This study showed that in order to achieve the targets of low emissions and high performance, the injection parameters and performances of the swirl chamber diesel engine should be designed and optimized according to its displacement just similar with the direct-injection diesel engine. The test results of 170F swirl chamber diesel engine showed that the brake specific fuel consumption (BSFC) of the original engine under the rated condition (2.6 kW, 3 000 r/min) was 327.3 g/(kW·h) and the smoke was 4.5 BSU. When the long-size short-structure nozzle was used and the fuel injection system was optimized, the BSFC and the smoke decreased to 282.2 g/(kW·h) and 2.0 BSU respectively. After the parameters of the combustion system were matched, the BSFC and the smoke dropped to 274.7 g/(kW·h) and 1.2 BSU respectively. The experimental results showed that the specific emissions of the optimized diesel were lower than the emission standards in Phase Ⅲ in China. Compared with results of the original engine, the CO and HC+NOX emissions decreased by 70.3% and 20.9% respectively under the 5 conditions. Moreover, the CO and HC+NOX emissions decreased by 72.8% and 21.3% respectively under the 8 conditions. The BSFC decreased by 16% and the diesel smoke was reduced from 4.5 to 1.2 BSU under the rated condition. The research provides a technology route of energy-saving and emission-reduction for swirl chamber diesel engines. [ABSTRACT FROM AUTHOR]

A mathematical model of Bosch 3rd generation Common Rail fuel injection system with piezoelectric injector has been created. The numerical calculations for third different accumulator pressures (30, 80 and 160 MPa) and third energizing times ET (0.5, 1 and 2 ms) have been carried out. The results of calculations of total injected mass per cycle have been compared with the experiment with good agreement. The maximum error for ET=0.5 ms is 10.4% and for ET≥1 ms is less than 5%. [ABSTRACT FROM AUTHOR]