Diesel Engine System Research Articles

Energy balance and emission analysis on diesel engine using different thermal barrier coated pistons

The energy balance assessment is an effective method for characterizing IC engines performance and efficiency. In this study, the impact on the energy balance system of diesel engines of the insulated heat transfer surfaces was examined. Four pistons are used in the current study, for all of the pistons using Ni-Cr-Al-Y as a bond coat of 50 µm thick. For LHR-1 Engine, the piston is insulated with (7% YSZ), LHR-2 Engine is (2%Nd + YSZ), LHR-3 Engine is (2%Gd + YSZ), and the LHR-4 Engine (2%Nd + 2%Gd + YSZ) as a top coat of 250 µm thick. The analysis of work is discussed in a four-stroke single- cylinder diesel engine. The outcomes obtained from this show that the CO and HC emission of a coated engine is reduced by 16.1% and 22.5% and the NOx emission is getting increased by 17.7% with a coated piston compared to the standard piston. The findings show a reduction of heat losses for the ceramic- coated engine cooling system.

Introduction of an Accurate Numerical Model to Predict the Reaction Process of UWS in Urea Selective Catalytic Reduction System of Diesel Engine

Introduction of an Accurate Numerical Model to Predict the Reaction Process of UWS in Urea Selective Catalytic Reduction System of Diesel Engine

Methodology for Detecting Faults in Injection Systems of Low-Displacement Diesel Engines by Diagnosing the Vibration Signal

In engines, the injection process is directly related to the atomization control and the detonation of the combustion mixture. A malfunction in this process caused by injectors’ failures leads to reduced engine efficiency, excessive noise, and damage. In this study, an analysis is proposed in order to detect problems in the injector by diagnosing the vibration signal of the engine body, especially the amplitude and the frequency of this type of signal. In order to carry out this study, a cylindrical mono diesel engine that varies its rotation speed by 3200, 3600, and 4000 rpm, at a constant torque of 3 Nm is used. For the vibration signal analysis, the study of the signal frequency, the Welch test, and the Fourier transform in the short term has been used. Additionally, parameters such as RMS and Kurtosis, which allow quantifying the effect of the injector on engine performance, have been evaluated. The analysis of the low and high frequency diagrams has proved to be a direct way to identify the status of the injectors. The Welch test allows observing that the defective injectors have a vibration signal intensity 44% higher than the healthy injectors. In general, the use of defective injectors has caused an 11% and 17% increase in the RMS and Kurtosis of the engine, compared to healthy injectors. In general, the study carried out shows that the fault detection in the injectors of IC engines is possible by measuring and evaluating the time-frequency of vibration signals from the engine body.

One-Dimensional Gas Flow Analysis of the Intake and Exhaust System of a Single Cylinder Diesel Engine

In order to design a diesel engine system and to predict its performance, it is necessary to analyze the gas flow of the intake and exhaust system. Gas flow analysis in a three-dimensional (3D) format needs a high-resolution workstation and an enormous amount of time for analysis. Calculation using the method of characteristics (MOC), which is a gas flow analysis in a one-dimensional (1D) format, has a fast calculation time and can be analyzed with a low-resolution workstation. However, there is a problem with poor accuracy in certain areas. It was assumed that the reason was that 1D could not implement the shape. The error that occurs in the shape of the bent pipe used in the intake and exhaust ports of the diesel engine was analyzed and to find a solution to the low accuracy, the results of the experiment and 1D analysis were compared. The discharge coefficient was calculated using the average mass flow rate, and as a result of applying it, the accuracy was improved for the maximum negative pressure by 0.56–1.93% and the maximum pressure by 3.11–7.86% among the intake pipe pressure results. The difference in phase of the exhaust pipe pressure did not improve. It is considered as a limitation of 1D analysis that does not improve even by applying the discharge coefficient. In the future, we intend to implement a bent pipe that cannot be realized in 1D using a 3D format and to prepare a method to supplement the reliability by using 1D–3D coupling.

Effects of Oxygenated Biomass Fuels on the Performance of Diesel Engine and After-Treatment System

Abstract Oxygenated biomass fuels have attracted significant attention due to their contributions in reducing environmental pollution and fossil fuel consumption. In view of stricter emission regulations, the use of these alternative fuels cannot fully meet the requirements, and it needs to be combined with an after-treatment system. In this article, polymethoxy dimethyl ether (PODE) and n-pentanol were blended with diesel (D100 (pure diesel)) at 15% and 20% by volume, respectively, referred to as D85P15, D80P20, D85A15, and D80A20, while the effects of the addition of two new oxygenated biomass fuels on the performance of diesel engine and diesel oxidation catalyst (DOC) and catalytic diesel particulate filter (CDPF) after-treatment system were experimentally investigated. Results show that the addition of oxygenated biomass fuels can improve combustion and reduce carbon monoxide (CO) and soot emissions. At heavy load conditions, when D80P20 was used, compared with D100 and D80A20, the conversion efficiency of CO emissions in DOC + CDPF system is always the highest, close to 100%. It shows that the addition of oxygenated biomass fuels can effectively improve the exhaust oxygen concentration. Besides, there is nearly no increase in CDPF pressure drop at each tested engine speed when D80P20 is used. This has greatly improved in CDPF performance.

Industrial scale 3D printed catalytic converter for emissions control in a dual-fuel heavy-duty engine

A full size ceramic substrate was successfully prepared using a robocasting 3D printer and tested as a methane oxidation catalyst in the after treatment system (ATS) of a heavy-duty diesel engine, converted to co-combust (dual fuel) with natural gas (NG). The 3D printed substrate performance exceeded that of a commercially sourced straight-channelled DOC over most working conditions, despite the 3D printed structure having a lower precious group metal (PGM) loading and channels per square inch (CPSI) density. At moderate and high inlet temperatures, where the reaction rate is limited by internal and external mass transfer, the enhanced catalytic activity of the 3D printed substrate is attributed to the generation of internal turbulence, which increases oxidation rates of methane (CH4) and non-methane hydrocarbons (NMHC). In contrast, there is relatively little difference between the catalytic activity of the 3D and straight-channelled substrates at low temperatures (e.g. cold start up), where the reaction is kinetically controlled and the additional turbulence/mass transfer of the 3D printed complex structure did not measurably alter the catalytic converter performance. Computational fluid dynamics (CFD) confirmed the increased turbulence within the channels of the 3D printed structure. We also report the effects of NG substitution on the fuel combustion efficiency under different engine load settings. The findings provide proof of concept evidence that 3D printing is a suitable means of designing a catalytic converter prototype with higher reaction activity than a conventionally extruded structure. This has significant implications for the design and potential mass production of new catalytic converters with enhanced efficiencies.

Investigation of Urea Uniformity with Different Types of Urea Injectors in an SCR System

Heavy-duty diesel engines in highway use account for more than 40% of total particulate and nitrogen oxide (NOx) emissions around the world. Selective catalytic reduction (SCR) is a method with effective results to reduce this problem. This research deals with problems in the urea evaporation process and ammonia gas distribution in an SCR system. The studied system used two types of urea injectors to elucidate the quality of ammonia uniformity in the SCR system, and a 12,000-cc heavy-duty diesel engine was used for experimentation to reduce NOx in the system. The uniformity of the generated quantities of ammonia was sampled at the catalyst inlet using a gas sensor. The ammonia samples from the two types of urea injectors were compared in experimental and simulation results, where the simulation conditions were based on experimental parameters and were performed using the commercial CFD (computational fluid dynamics) code of STAR-CCM+. This study produces temperatures of 371 to 374 °C to assist the vaporization phenomena of two injectors, the gas pattern informs the distributions of ammonia in the system, and the high ammonia quantity from the I-type urea injector and high quality of ammonia uniformity from the L-type urea injector can produce different results for NOx reduction efficiency quality after the catalyst process. The investigations showed the performance of two types of injectors and catalysts in the SCR system in a heavy-duty diesel engine.

Análisis CFD del comportamiento del flujo de aire en el sistema de admisión de un motor diésel de baja cilindrada

Introducción— El análisis del flujo de aire, en Motores de Combustión Interna expone un gran desafío para los investigadores debido al comportamiento que presenta el aire dentro del cilindro, el cual se caracteriza por ser turbulento, inestable, cíclico y no estacionario tanto espacial como temporalmente. El presente estudio propone implementar de un modelo de turbulencia a través de un análisis de Dinámica de Fluidos Computacional (CFD) que permita simplificar el fenómeno para motores de baja cilindrada y describa los parámetros que repercuten en la eficiencia y emisiones del motor. Objetivos— El presente estudio busca analizar el comportamiento del flujo de aire en el sistema de admisión de un motor Diésel de baja cilindrada con aspiración natural a través de un modelo experimental ajustado mediante un modelado CFD. Metodología— Se realizó el análisis del comportamiento del flujo de aire en el sistema de admisión del motor con un modelo experimental que obtiene las características del flujo. Este modelo es ajustado mediante herramientas CFD en OPENFOAM®, que permitirá obtener el Coeficiente de Descarga (CD) y el Coeficiente de Torbellino (CT) para describir el comportamiento aerodinámico del sistema de admisión. Resultados— Para el CD, los valores oscilan entre 0 L/D y 0.5 L/D indicando que este motor es capaz de trasegar un 50% de aire de la capacidad teórica con una válvula de 30.5 mm de diámetro y una cámara de 0.3 L de volumen. En cuanto al CT, para un área de referencia variable, los valores oscilan entre 0.19 L/D y 0.3 L/D, por lo que el motor solo disminuiría un 11% su capacidad de trasegar flujo de aire de la capacidad ideal, si el flujo másico teórico va en aumento para cada levantamiento. Conclusiones— Se puede concluir que para 3000 rpm y 3400 rpm se produce un vórtice definido bajo la metodología propuesta, obteniendo valores de velocidad muy cercanos a 10 m/s y 20 m/s en la periferia, que aseguran el flujo de aire con vorticidad en el cilindro. A 3400 rpm el CT se eleva con respecto a los demás regímenes en los últimos levantamientos de válvula. Concluyendo así, que bajo este régimen de giro se da el punto óptimo de generación de vorticidad para el motor que permite reducir las emisiones e incrementar le eficiencia global.

Study of the Piston Secondary Movement on the Tribological Performance of a Single Cylinder Low-Displacement Diesel Engine

The present study aims to analyze the secondary movement of the piston considering the deformations present in the piston skirt, the hydrodynamic lubrication, and the effects of the clearances in the connecting rod bearings. The analysis of the piston movement is performed by developing a mathematical model, which was used to evaluate the dynamic characteristics of the piston movement, the slap force on the piston skirt, the effect of the secondary piston movement on the connecting rod, and the influence of clearances in the connecting rod bearings and in the piston. For the study, the geometric of the crankshaft-connecting rod–piston system of a single-cylinder diesel engine is taken as a reference. The deformation model of the piston was carried out by means of a symmetric finite element model (FEM), which was integrated into the mathematical model of the piston. MATLAB® software (The MathWorks Inc., Natick, MA, USA) is used for the development of model simulations. The obtained results show that during the combustion cycle, there are six changes of direction in the secondary movement of the piston with lateral and angular velocities that can reach a magnitude of 0.13 m/s and 4 rad/s. The lateral and angular movement of the piston during its travel causes the appearance of impacts on the piston skirt with the cylinder liner, which produces an increase of approximately 500 N in the hydrodynamic forces in the connecting rod bearings. The force analysis shows that the range of the maximum magnitudes of these forces is between 1900 N and 3480 N. The increase in clearance between the cylinder liner and the piston skirt (Cpc) causes a greater lateral displacement and an increase in the angle of inclination of the piston. Analysis of the change in connecting rod bearing clearance shows that there are critical values in relation to clearance Cpc. The model presented allows us to analyze the different characteristics of the secondary movement of the piston, which involve the interaction between the piston skirt and the cylinder liner. Additionally, the influence of this movement on the connecting rod bearings is considered. The foregoing can be used as an analysis tool for the study of designs and/or modifications in the engine in such a way that greater durability of the components, reductions in acoustic emissions, and reduction in friction losses are achieved.

Vibration responses of rotor systems in diesel multiple units under dynamic spatial misalignments and base motions

To achieve high performance monitoring of the electric transmission powerpack for a diesel multiple unit (DMU), the dynamic responses of the rotor system inside the powerpack with dynamic spatial misalignment (DSM) and base motions from car body are investigated through structural modeling and numerical analysis. A three-dimensional coupled model, including public framework, diesel engine, electric generator and rotor system, is developed. Vibrations under deterministic and random base motions are numerically calculated using the Newmark Method. The simulation results show that vibration responses of the coupled model are evidently different from those of rotors with a fixed base. DSM is more nonlinearly sensitive to the deterministic base motion than rotor vibrations, and the converse is true when the base pitch motion is random in frequency. Additionally, results show that DSM may vary significantly in different axial positions, with large base motions in some extreme situations. These findings lay the primary foundations for implementing vibration-based condition monitoring of DMU diesel-generator systems.

Effects of intake swirl on the fuel/air mixing and combustion performance in a lateral swirl combustion system for direct injection diesel engines

To study how intake swirl affects the combustion performance of the lateral swirl combustion system (LSCS), experiments under different swirl ratios were carried out in a single-cylinder diesel engine to optimize the circumferential injection angle (CIA) and test the eventual combustion performance. Then, simulation under different swirl ratios was conducted to reveal the influence mechanisms of intake swirl on the fuel/air mixing characteristics of the LSCS.Experimental results show that, as the swirl ratio (SR) was increased from 0 to 1.0, the optimal CIA increased 2.5° in the opposite direction to that of the intake swirl. Besides, the LSCS obtained better combustion performance with SR = 0 than with SR = 1.0, especially at high loads and low excess air coefficients. Simulation results indicate that, generating intake swirl weakens the wall-flow-guided and interferential interactions of the LSCS, thereby deteriorating the in-cylinder air utilization and fuel/air mixing uniformity, especially at high loads and low excess air coefficients, in which the interactions between the LSCS chamber and spray jets is strong due to the enhanced spray penetration ability. Therefore, the LSCS without intake swirl obtains the optimal fuel/air mixing and combustion performance in DI diesel engines.

Research on Densification Mechanism of Hot Isostatic Pressing Technology in Nickel-Based Superalloys for Marine Environment

Jiang, Z.; Wang, J., and Cao, D., 2020. Research on densification mechanism of hot isostatic pressing technology in nickel-based superalloys for marine environment. In: Wan, Z. (ed.), Coordinated Sustainable Development in Coastal Areas: Environment and Economy. Journal of Coastal Research, Special Issue No. 109, pp. 100–104. Coconut Creek (Florida), ISSN 0749-0208.Nickel-base superalloy is one of the major materials employed in the manufacturing process of air valve and exhaust system of diesel engine, turbine disk and blade of gas turbine and nuclear power units. The rapid development of modern marine industry is inseparable from the rapid improvement of comprehensive properties of superalloy. In this process, hot isostatic pressing (HIP) technology has been playing a significant role in the application of Nickel-base superalloy. In this paper, the research and application of HIP technology in the field of Nickel-base superalloy are herein summarized, and concluding the effect of HIP technology on densification mechanism and properties of cast superalloy.

Efficiency Control Improvement Of Diesel Engines Conditions By Using The Method Of Analytical Synchronization Of Monitored Data

Improving the efficiency of the ship's diesel power plant is becoming increasingly important every year. This is primarily due to the restrictions on emissions of sulfur and nitrogen oxides into the atmosphere during the operation of the ship's diesel engines. Article is devoted to the problem of synchronization of data monitoring working process in transport diesel engines operation. The accuracy of data synchronization determines the error in determining power, control of the main engine systems operation and its diagnostics. The method of solving the synchronization problem must be analytical. The method of solving the synchronization problem must be analytical. In comparison the hardware methods used in most diagnostic systems of the working process of diesel engines have several disadvantages. It is impossible to conduct rapid diagnostic control in operation, non-stationary phase and amplitude errors in calculation the main parameters of the working process, the need for preparatory operations and related need for temporary withdrawal of diesel engine operation, complexity and high cost of diagnostic control. An analytical synchronization method is developed based on the top dead center coordinate determination algorithm, which uses three stages: linear, sinusoidal and model equal to zero the first derivative of the pressure under compression. The proposed method of analytical synchronization gives the obvious advantages for monitoring working process systems of diesel engines. The error in determining the main parameters of the working process and the indicator power does not exceed 2.5%.

Modeling and feedback linearization based sliding mode control of diesel engines for waterjet propulsion vessels

Efficient and stable operation of marine diesel engines is crucial both for navigation maneuverability and safety of waterjet propulsion vessels. In this paper, a piecewise linear model and an affine nonlinear model of marine diesel engines are established by applying mechanism analysis techniques. The models are validated with the experimental data collected from a 290 kW (maximum power) diesel engine equipped on a waterjet propulsion vessel. The relative error of engine speed between model simulation and the measurements is found less than 3%. To improve the performance of the speed regulation system of diesel engines, a sliding mode control strategy is developed on the basis of the affine nonlinear model utilizing the equivalent control method. Simulation results are presented to illustrate the effectiveness of the proposed control strategy regarding model mismatch, response speed, disturbance rejection, and engine speed tracking ability.

An Evaluation of Human Error Probabilities for Critical Failures in Auxiliary Systems of Marine Diesel Engines

Human error, an important factor, may lead to serious results in various operational fields. The human factor plays a critical role in the risks and hazards of the maritime industry. A ship can achieve safe navigation when all operations in the engine room are conducted vigilantly. This paper presents a systematic evaluation of 20 failures in auxiliary systems of marine diesel engines that may be caused by human error. The Cognitive Reliability Error Analysis Method (CREAM) is used to determine the potentiality of human errors in the failures implied thanks to the answers of experts. Using this method, the probabilities of human error on failures were evaluated and the critical ones were emphasized. The measures to be taken for these results will make significant contributions not only to the seafarers but also to the ship owners.

Available Energy in Cars’ Exhaust System for IoT Remote Exhaust Gas Sensor and Piezoelectric Harvesting

The exhaust system of the light-duty diesel engine has been evaluated as a potential environment for a mechanical energy recovery system for powering an IoT (Internet of Things) remote sensor. Temperature, pressure, gas speed, mass flow rate have been measured in order to characterize the exhaust gas. At any engine point explored, thermal energy is by far the most dominant portion of the exhaust energy, followed by the pressure energy and lastly kinetic energy is the smallest fraction of the exhaust energy. A piezoelectric flexible device has been tested as a possible candidate as an energy harvester converting the kinetic energy of the exhaust gas flow, with a promising amount of electrical energy generated in the order of microjoules for an urban or extra-urban circuit.

Study on prediction model of diesel engine with regulated two-stage turbocharging system based on hybrid genetic algorithm-particle swarm optimization method at different altitudes

ABSTRACT Aiming at the problem of complicated mechanism modeling for regulated two-stage turbocharging (RTST) system of diesel engine, a hybrid genetic algorithm–particle swarm optimization (GA-PSO) method was applied to optimize back propagation neural network (BPNN) performance prediction model of diesel engine. First, using a high-altitude (low-pressure) simulation test bench for diesel engines, a full-load performance test of RTST diesel engine at different altitudes was carried out, and the regulation rules of diesel engine intake characteristics and two-stage turbocharger (TST) matching characteristics with altitude were obtained. Based on the test data, the BPNN is used to establish the boost pressure prediction model of the RTST system of the diesel engine. For the problem of slow convergence and low prediction accuracy of the BPNN, adaptive improvement measures such as momentum and learning rate are introduced, and the GA-PSO optimizes the weights and thresholds of BPNN. The performance comparison shows that hybrid GA-PSO is superior to particle swarm optimization (PSO) and genetic algorithm (GA) in terms of evolution speed and convergence accuracy. Genetic algorithm–particle swarm optimization–back propagation neural network (GA-PSO-BPNN) model has higher prediction accuracy and higher accuracy than particle swarm optimization–back propagation neural network (PSO-BPNN) model and genetic algorithm–back propagation neural network (GA-BPNN) model. Compared with the original model, the root-mean-square error of the model is reduced by 50%, the mean error percentage (MEP) is reduced by 38%, and the sum of the squared errors is reduced by 79%. The performance verification of the GA-PSO-BPNN model shows that the MEP of the model prediction results is 5.5%, and the GA-PSO-BPNN model has higher prediction accuracy.

Design and optimisation of an advanced waste heat cascade utilisation system for a large marine diesel engine

Growing energy shortages severely restricting the sustainable development of human beings, improving energy efficiency has become an urgent issue. To improve energy efficiency, the dual-pressure organic Rankine cycle, which is an efficient waste heat recovery technique for ships, has received increasing attention. Most researchers have investigated the dual-pressure organic Rankine cycle with pure working fluids, which do not yield the best thermodynamic and economic performance. In addition, some low-grade waste heat sources in the engine have been neglected. To completely recover the waste heat energy of marine engines, a novel waste heat recovery technique with a dual-pressure organic Rankine cycle system, desalination plant, and two-bed regenerative adsorption refrigeration device is presented for recovering residual heat from the exhaust gas, jacket water, charge air, and lubricating oil. Based on a comparison of the thermodynamic performance, safety, and environmental effects, the zeotropic working fluid pair dimethyl carbonate/perfluoropropane is selected. The mathematical model of the proposed integrated system is evaluated to ensure accuracy, and its critical parameters are analysed based on its thermodynamic and economic performance. A multi-objective artificial bee colony algorithm is adopted to optimise the system. The results show that the proposed integrated system can recover 354.65 kW net power and increase the thermal efficiency by 4.2% on average; at the most frequently used engine load, a refrigeration capacity of 88 kW and a fresh water rate of 146 kg/h are achieved. This work promotes the development of the energy recycling.

On the Influencing Factors of Integrated Aftertreatment System in Diesel Engine

In order to reduce the pollutants of diesel exhaust, DOC, DPF, SCR, AOC, etc. are mainly used for off-machine after-treatment technology, but it is difficult to meet the requirements of the newest emission regulations simply by relying on a certain aftertreatment technology. Therefore, the use of integrated aftertreatment system has become a necessary choice. In this paper, the research object is one of the integrated aftertreatment systems (DOC+DPF+ SCR+AOC). Then, the effects of the different exhaust parameters, the different structural parameters and different chemical reaction parameters on the catalytic conversion efficiency of NOx, HC, CO, and PM are studied.

Modelling and Simulation Analysis of High-Pressure Common Rail and Electronic Controlled Injection System for Diesel Engine

Abstract The electronically controlled fuel injection system of the diesel engine has multi-disciplinary characteristics and strong coupling. The programming method based on a mathematical model cannot be applied to the fuel system with a diversified structure arrangement. With the rapid development of hydrodynamics, more and more simulation software is applied in the actual research. Hydsim simulation platform is one of the best software for the simulation of the electronic control injection system. In this paper, the Hydsim simulation platform is used to simulate the electronic control injection system, and a test-bed for verification is built. Based on the experimental results, the injection characteristics of high-pressure common rail are studied. The validity and accuracy of the simulation model are verified by comparing the simulation value with the test value and the standard value. Finally, the influence of the structural parameters such as the inlet and outlet orifices and control pistons of the injection system on the injection characteristics is analysed, and the selection principle of each parameter in the system design is proposed, which provides a reliable basis for the structural optimisation.