Type Diesel Engine Research Articles

Investigation on combustion process and emissions characteristic in direct injection diesel engine powered by wet ethanol using blend mode

This paper presents results of investigation of the engine powered by diesel–ethanol fuel blends with wide range of ethanol fraction. Two supply systems of fuel pump are investigated. It is used two supply systems of fuel pump: low pressure 0.1bar and high pressure 1bar. Researches are conducted on 1-cylinder direct injection compression ignition engine with constant rotational speed 1500rpm. Thermodynamic parameters and exhaust emission of engine powered by fuels blend are taken into account. Heat release rate and pressure rise have been analyzed as well. Test results confirmed that the combustion process occurring in the diesel engine powered by blend takes place in a shorter time than in the typical diesel engine. High pressure supply system (HPSS) allows to combustion blends with higher ethanol fraction, up to 45%. With high pressure supply system the value of indicated mean effective pressure (IMEP) up to 40% of ethanol fuel fraction kept almost constant with value near to 6bar. For 15% ethanol fuel fraction in HPSS case the COVIMEP was 2.5-times lower then in low pressure supply system (LPSS) case. In both supply systems emission of THC increased or was on near a constant level. With the increase of ethanol fraction in blend the NOx increased as far as combustion process started to deteriorate.

Comparative performance analysis of jatropha, karanja, mahua, and polanga based biodiesel engine using hybrid genetic algorithm

The nonedible based biodiesels (jatropha, karanja, mahua, and polanga) have been evaluated in a single cylinder, direct injection diesel engine for their performance, combustion, and emission parameters using hybrid response surface methodology-non-dominated sorting genetic algorithm-II technique. The sets of pareto optimum solutions for each biodiesel produced have also been presented in the form. Confirmation tests are also conducted at randomly selected few pareto solutions to check the authenticity of the results. None of the solutions is better than the other, and each solution has its own importance. The summary of desired performance, combustion, and emission parameters of produced biodiesels is presented for further use in the diesel engine. The results obtained are far reaching and they can be directly referred to for similar types of diesel engines.

Эволюция материалов ответственных компонентов малооборотных судовых дизелей

With the growth of average effective pressure in cylinders of marine lowspeed diesel engines the requirements increased to materials used for manufacturing their critical parts. This paper reports the dynamics of mechanical data changes in materials (steel and cast iron) of critical parts in diesel engines by the example of produce of the Bryansk engineering plant. From 1961 till 2008 the Bryansk engineering plant is the only manufacturer of powerful marine low-speed diesel engines in Russia. Diesel engines were being built under licence of “MAN Burmeister Diesel” Co. Diesel engines manufactures in different years differ with forcing degree. A diesel engine with a higher forcing degree has a higher value of mean effective pressure. In the paper there are shown types of diesel engines manufactured by the Bryansk engineering plant and is shown the evolution of mechanical data of cylinder iron bushes, piston rings, steel components of a bed frame, crankshafts. 
 It is pointed out that the application of new steel and cast iron kinds should follow considerable changes in the design of marine low-speed diesel engines of the type 6DKRN 50/200-14 of compact modification. 
 The conclusion is drawn of that with the growth of a forcing degree in diesel engines the mechanical data of steel and cast iron will increase at the expense of material chemistry changes by means of the introduction of alloying elements and application of modern metallurgical equipment for qualitative billet manufacturing.

ECOLOGICAL IMPACT OF WIND-DIESEL POWER PLANTS ON ECOSYSTEM AND POPULATION HEALTH

In electrification of the Eastern regions of Russia, an important part is assigned to the small-scale power distributed generation. In this regard, it is actual to construct wind-diesel power plants (WDPP), which impact on humans and environment is so far poorly studied. The results of a theoretical research of WDPP negative impact on health of the population and ecosystem of the territories of the East of Russia which were not covered by the centralized power supply have been given in the article. The assessment of indicators of atmospheric air pollution (specific and absolute values of the specified mass of annual emission of harmful substances, volumes of greenhouse gases emission, formation of acid rainfall, substances causing eutrophication) and physical pollution (noise, electromagnetic field) during use of WDPP of various rated capacity. Calculations have been done for 692 types of diesel engines and 97 models of wind power installations. The received results were compared with the level of environmental pollution during work of large thermal power plants. There have been given graphic dependences of the specified mass of the emitted harmful substances on power of the diesel engines, a noise level created by the wind power installations, on remoteness of settlements and power of the power installations, as well as a ratio of volume of harmful substances annual emission in the atmosphere during work of WDPP and the large thermal power plants. It has been shown that electrification of the Eastern regions of Russia on the basis of development of small-scale power distributed generation would have an ecological focus.

A fault diagnosis approach for diesel engines based on self-adaptive WVD, improved FCBF and PECOC-RVM

Targeting the cross-term interference of Wigner–Ville distribution (WVD) and the redundancy control problem of fast correlation-based filter (FCBF), a novel approach based on self-adaptive WVD, improved FCBF and relevance vector machine (RVM) is proposed for the identification of diesel engine fault in this study. The approach primarily consists of three stages. Firstly, the self-adaptive WVD method is used to generate the time–frequency images of the vibration signals of the diesel engine. Secondly, four types of commonly used image features, including moment invariants, gray statistical characteristics, textural features and the differential box-counting fractal dimension, are calculated for all of the time–frequency images. Next, the improved FCBF method is proposed and used to select the relevant but non-redundant fault features. Finally, the probability-based error correcting output codes (PECOC) method is used to determine the structure of the multi-RVM model, and the fault diagnosis results can be obtained by inputting the selected fault features into the PECOC-RVM classifier. The simulation and experimental results demonstrate that the proposed fault diagnosis approach can overcome the cross-term interference of WVD, effectively extract the relevant but non-redundant fault features and accurately identify the fault types of diesel engines.

Multi-approach evaluations of a cascade-Organic Rankine Cycle (C-ORC) system driven by diesel engine waste heat: Part A – Thermodynamic evaluations

A novel transcritical cascade-Organic Rankine Cycle (C-ORC) system was proposed to recover multi-grade waste heat from a typical heavy-duty diesel engine. The C-ORC comprises of a high-temperature ORC loop (HT-Loop) and a low temperature ORC loop (LT-Loop) to recover waste heat from an engine’s exhaust gas (EG), exhaust gas recirculation (EGR), jacket water (JW) and charge air (CA) in a cascaded pattern. In order to reveal the full performance of the C-ORC system, with due consideration to diesel’s complex practical running conditions, multi-approach evaluations were conducted containing two parts: Part A – thermodynamic evaluations of the energy and exergy aspects and Part B – techno-economic evaluations on costs and benefits aspects.This paper shows the Part A – evaluations of the C-ORC, focusing on indexes including recovered waste heat, net power output, thermal efficiencies and exergy efficiencies. First of all, distributions of the engine’s multi-grade waste heat were studied to reveal the characteristics and utilization potential of waste energy. The comparison and screening of working fluids were carried out next to find the best fluids for the HT-Loop and LT-Loop respectively based on the rated engine condition. Toluene, decane, cyclohexane and D4 were four proper alternatives for the HT-Loop while R143a, R125, R218 and R41 were four proper alternatives for the LT-Loop. Comparisons indicated that toluene and R143a made the perfect match for the C-ORC with the highest net power output (33.9kW), thermal efficiency (9.9%) and exergy efficiency (39.1%). The rankings of the two groups of alternate fluids based on their thermodynamic performance were: toluene>decane>cyclohexane>D4 and R143a>R125>R218>R41. Finally, the C-ORC’s performance was evaluated based on the engine’s practical operating conditions. Results indicated that, the engine’s waste heat was only able to drive the C-ORC system when the engine torque was higher than 917Nm. The maximal recovered heat of the EG, EGR, CA and JW were 153.0kW, 9.1kW, 37.5kW and 267.0kW under available conditions; the highest net power output, thermal efficiency and exergy efficiency were 38.2kW, 11.3%, 38.7% respectively; and the largest efficiency increment to the original engine was up to 16.0%. Summarily, thermodynamic evaluations from Part A – reveal that the proposed C-ORC has significant heat-recovery capacities and efficiency-promotion potential.

Multi-approach evaluations of a cascade-Organic Rankine Cycle (C-ORC) system driven by diesel engine waste heat: Part B-techno-economic evaluations

A novel transcritical cascade-Organic Rankine Cycle (C-ORC) system was proposed for recovering multi-grade waste heat from a typical heavy-duty diesel engine. The C-ORC comprises a high temperature ORC loop (HT-Loop) and a low temperature ORC loop (LT-Loop) for recovering waste heat from engine exhaust gas (EG), exhaust gas recirculation (EGR), jacket water (JW) and charge air (CA) in a cascaded pattern. The basic thermodynamic evaluation on energy and exergy aspects were covered in the companion piece-‘Part A-thermodynamic evaluations’, indicating that the proposed C-ORC possesses great heat-recovery capacities and efficiency-promotion potentials. The techno-economic evaluations in Part B of this paper will further explore the performance of the C-ORC system based on costs and benefits in order to reveal its practical benefits.Four techno-economic indexes are mainly focused on: component-to-system cost ratio (CSCR), electricity production cost (EPC), depreciated payback period (DPP) and savings-to-investment ratio (SIR). Under rated engine conditions, working fluids were initially compared to find the most economical fluids for the HT-Loop and the LT-Loop respectively. Results indicated that toluene and R143a still make the perfect match for the C-ORC with the lowest EPC (0.27Dollar/kWh), DPP (7.8years) and the highest SIR (1.6). As to component-to-system cost ratio (CSCR), the cost of expanders and heat exchangers together account for more than 3/4 of the total system cost, and the expander of the LT-Loop is the most costly single component. The C-ORC’s techno-economic performance was further evaluated based on engine’s practical operating conditions. Results showed that, under available conditions, the CSCR of expanders is within 25.9–48.0%, and it gradually increases as engine’s speed and torque increase; the CSCRs of heat exchangers and pumps are within 31.1–54.8% and 17.7–22.5% respectively. The EPC, DPP and SIR are within 0.27–0.48Dollar/kWh, 8.5–20.5years and 0.85–1.6 respectively, and according to their similar variations, an increase in engine speed will evidently benefit three indexes. In addition, the increasing torque will also improve the indexes to some extent.Summarily, the techno-economic evaluations in Part B of this paper further reveal the C-ORC’s merits and drawbacks, and in order to improve its full performance, provide directions for optimizations for higher system capacities and commercial potentials.

Numerical Simulation of the Effect of 3D Needle Movement on Cavitation and Spray Formation in a Diesel Injector

Cavitation and its effect on spray formation and its dispersion play a crucial role in proper engine combustion and controlled emission. This study focuses on these effects in a typical common rail 6-hole diesel injector accounting for 3D needle movement and flow compressibility effects. Coupled numerical simulations using 1D and 3D CFD codes are used for this investigation. Previous studies in this direction have already presented a detailed structure of the adopted methodology. Compared to the previous analysis, the present study investigates the effect of 3D needle movement and cavitation on the spray formation for pilot and main injection events for a typical diesel engine operating point. The present setup performs a 3D compressible multiphase simulation coupled with a standalone 1D high pressure flow simulation. The simulation proceeds by the mutual communication between 1D and 3D solvers. In this work a typical common rail injector with a mini-sac nozzle is studied. The lateral and radial movement of the needle and its effect on the cavitation generation and the subsequent spray penetration are analyzed. The result indicates the effect of compressibility of the liquid on damping the needle forces, and also the difference in the spray penetration levels due to the asymmetrical flow field. Therefore, this work intends to provide an efficient and user-friendly engineering tool for simulating a complete fuel injector including spray propagation.

Piston ring-cylinder liner tribology investigation in mixed lubrication regime: part I-correlation with bench experiment

Purpose – The purpose of this paper is to improve the environment and save energy, friction reduction, lower oil consumption and emissions demand that are the chief objectives of the automotive industry. The piston system is the largest frictional loss source, which accounts for about 40 per cent of the total frictional loss in engine. In this paper, the reciprocating tribometer, which is updated, was used to evaluate the friction and wear performances. Design/methodology/approach – An alternate method is introduced to investigate the effect of reciprocating speed, normal load, oil pump speed and ring sample and oil temperature on friction coefficient with the ring/liner of a typical inline diesel engine. The orthogonal experiment is designed to identify the factors that dominate wear behavior. To understand the correlations between friction coefficients and wear well, different friction coefficient results were compared and explained by oil film build-up and asperity contact theory, such as the friction coefficient over a long period and averaged the friction coefficient over one revolution. Findings – The friction coefficient changes little but fluctuates with a small amplitude in the stable stage. The sudden change of frequency, load and stroke will lead to the oil film rupture. The identification for the factors that dominates the wear loss is ranged as F (ring sample) > , E (oil sample) > , B (stroke) > , D (temperature) > , A (load) > , G (liner) > and C (frequency). Originality/value – This paper develops and verifies a methodology capable of mimicking the real engine behavior at boundary and mixed lubrication regimes which can minimize frictional losses, wear, reduce much work for the experiment and reduce the cost. The originality of the work is well qualified, as very few papers on a similar analysis have been published, such as: The friction coefficient values fluctuating in the whole stage may be caused by the vibration of the system; suddenly, boundary alternation may help the oil film to form the lubrication; and weight loss mainly comes from the contribution of the friction coefficient value fluctuation. The paper also found that the statistics can gain more information from less experiment time based on a design of experiment.

Effect of Cetane Improver on Combustion and Emission Characteristics of Coal-Derived Sasol Isomerized Paraffinic Kerosene in a Single Cylinder Diesel Engine

Sasol isomerized paraffinic kerosene (IPK) is a coal-derived synthetic fuel under consideration as a blending stock with JP-8 for use in military ground vehicles. Since Sasol IPK is a low ignition quality fuel with derived cetane number (DCN) of 31, there is a need to improve its ignition quality. This paper investigates the effect of adding different amounts of Lubrizol 8090 cetane improver to Sasol IPK on increasing its DCN. The experimental investigation was conducted in a single cylinder research type diesel engine. The engine is equipped with a common rail injection system and an open engine control unit. Experiments covered different injection pressures and intake air temperatures. Analysis of test results was made to determine the effect of cetane improver percentage in the coal-derived Sasol IPK blend on auto-ignition, combustion and emissions of carbon monoxide (CO), total unburned hydrocarbon (HC), oxides of nitrogen (NOx), and particulate matter (PM). In addition, the effect of cetane improver on the apparent activation energy of the global auto-ignition reactions was determined.

연료설계에 의한 에멀젼연료의 거동특성에 관한 기초연구

A compression ignition type of diesel engine makes fuel efficiency better and <TEX>$CO_2$</TEX> in the exhaust gas lower. Also it is suitable to apply alternative fuels(blended fuel) to the engine. The objective of this study is the emissions reduction of diesel engine with EF(Emulsified fuel). The emulsified fuel consists of diesel and peroxide(<TEX>$H_2O_2$</TEX>) and Soot reduction without worsening of NOx emissions can be achieved by using thermal decomposition of the peroxide, i.e. the chemical effect of the OH radical in actual engine. For manufacturing emulsified fuel, a surfactant which is comprised of span 80 and tween 80 mixed as 9:1, was mixed with a fixed with 3% of the total volume in the emulsion fuel. In addition, considering the mixing ratio of the surfactant, the mixing ratio of <TEX>$H_2O_2$</TEX> in the emulsified fuel was set as EF0, EF2, EF12, EF22, EF32, and EF42, respectively. Consequently, this study aims to obtain the optimization of fuel design(mixing) for the emulsified fuel applying to the diesel engine.

Analysis of thermoelastohydrodynamic performance of journal misaligned engine main bearings

To understand the engine main bearings’ working condition is important in order to improve the performance of engine. However, thermal effects and thermal effect deformations of engine main bearings are rarely considered simultaneously in most studies. A typical finite element model is selected and the effect of thermoelastohydrodynamic(TEHD) reaction on engine main bearings is investigated. The calculated method of main bearing’s thermal hydrodynamic reaction and journal misalignment effect is finite difference method, and its deformation reaction is calculated by using finite element method. The oil film pressure is solved numerically with Reynolds boundary conditions when various bearing characteristics are calculated. The whole model considers a temperature-pressure-viscosity relationship for the lubricant, surface roughness effect, and also an angular misalignment between the journal and the bearing. Numerical simulations of operation of a typical I6 diesel engine main bearing is conducted and importance of several contributing factors in mixed lubrication is discussed. The performance characteristics of journal misaligned main bearings under elastohydrodynamic(EHD) and TEHD loads of an I6 diesel engine are received, and then the journal center orbit movement, minimum oil film thickness and maximum oil film pressure of main bearings are estimated over a wide range of engine operation. The model is verified through the comparison with other present models. The TEHD performance of engine main bearings with various effects under the influences of journal misalignment is revealed, this is helpful to understand EHD and TEHD effect of misaligned engine main bearings.

Appropriate structural parameters of biogas SI engine converted from diesel engine

A simulation of effects of combustion chamber shape, compression ratio, and spark timing advance to the performance of a biogas spark-ignition (SI) engine converted from a diesel engine is presented. It is a comparative research which uses computational fluid dynamics (CFD) software FLUENT for identifying basic structural parameters of the diesel engine that could be modified in order to obtain a high performance biogas engine. The presence of CO2 in biogas fuel slows down the burning velocity of the mixture, thus any mechanisms speeding up the combustion would be desirable. Under the same operating conditions of biogas engine, an increase of indicated cycle work is observed as replacing flat combustion chamber shape by omega combustion chamber shape. Optimal spark timing advance of a biogas engine is greater than that of a gasoline engine and it depends on engine speed and/or on CH4 fraction in the biogas. At rated regime of engine fueled with normal biogas, the results pointed out an optimal value of compression ratio. The research is successfully applied to convert a typical ZH1115 diesel engine to a biogas SI engine. The evidence developed from this research can be applied to any other diesel engine.

Numerical Study of Effects of Piston Bowl Geometry on the Intake Generated Swirl in a PCCI Engine

Numerical investigations were conducted on a DI diesel engine modified to be run as a premixed charge compression ignition engine to determine its flow field near TDC. A three dimensional CFD analysis was done on a typical diesel engine and validated against experimental data. The standard bowl was compared with modified bowl 2 and 3. It is seen that while Bowl 2 was able to generate higher swirl, bowl 3 generated a slightly higher turbulence at TDC. Hence this bowl is more suitable for use in diesel and a detailed spray and combustion analysis will provide more insight into the actual pollutant formation and combustion.

Investigation of effect of cyclic fuel delivery on start mode of small-sized diesel engine CH8,5 / 11

The article considers the possibility of improving starting characteristics of small-size diesel engine type CH8,5/11 by replacing vortex combustion chamber by piston combustion chamber. The authors present the formulas for determination of optimum amount of cycle fuel supply in diesel engine start mode, fuel vaporization in start mode in volume and from the wall of a cylindrical combustion chamber. Results of experimental studies show the influence of cycle fuel supply on duration of small-sized diesel start-up.

ATOMIZATION MODELLING OF LIQUID JETS USING A TWO-SURFACE-DENSITY APPROACH

In internal combustion engines, the liquid fuel injection is an essential step for the air/fuel mixture preparation and the combustion process. Indeed, the structure of the liquid jet coming out from the injector plays a key role in the proper mixing of the fuel with the gas in the combustion chamber. The present work focuses on the liquid jet atomization phenomena under diesel engine conditions. Under these conditions, liquid jet morphology is assumed, including a separate liquid phase (i.e., a liquid core) and a dispersed liquid phase (i.e., a spray). This article describes the developmental stages of a new atomization model, for a high-speed liquid jet, based on an Eulerian-Eulerian two-fluid approach. The atomization phenomena are modelled by defining different surface density equations for the liquid core and the spray droplets. This new model has been coupled with a turbulent and highly compressible two-fluid system of equations. The process of ligament breakup and its subsequent breakup into droplets are handled by acquiring knowledge from the available high-fidelity experiments and numerical simulations. In the dense region of the liquid jet, the atomization is modelled as a dispersion process due to the stretching of the interface, from the liquid side in addition to the gas side. The model results have been compared to a recently published DNS results under typical direct injection diesel engine conditions. In particular, it has been shown that the interface instabilities and the turbulence in the leading tip of the liquid core play a major role in the primary atomization of diesel jets.

Influence of biodiesel and diesel fuel blends on the injection rate under cold conditions

During start-up of the engine under cold temperatures, conditions can be different when biodiesel is used due to the low fuel injection pressure and the high cloud point and high pour point. It is consequently of interest to understand the behavior of the injector under cold conditions when operating with biodiesel and the impact on the combustion process. This article presents an experimental study of the influence of diesel fuel and biodiesel blends on injection flow. A Bosch CRI 3.1 piezoelectric injector was used on a typical diesel engine. Five fuel types were tested: diesel fuel, winter diesel fuel, two diesel–biodiesel blends (B20, B50), and pure biodiesel (B100). Injection pressures were set at 30–60MPa for the study of the injection flow characteristics at room temperature, in non-vaporizing conditions and in cold conditions. The experimental results show that cold temperatures (−5 and −8°C) have no effect on the injection delay for any of the fuels. The discharge coefficients for all fuels are lower than at room temperature. When the fraction of biodiesel in the blend is increased, the change in the discharge coefficients is insignificant. New correlation coefficients for estimating the kinematic viscosity and the discharge coefficient has been presented for cold conditions.

Numerical modeling of lubrication of piston ring of two-stroke marine diesel engine considering the effect of multi-scale grooves on the cylinder liner

The method of lubrication for piston ring in some types of low-speed two-stroke marine diesel engines is completely different from those in medium- or high-speed diesel engines since the inner surface of cylinder liners are textured with elliptical grooves in macroscale and honing texture in microscale. In this paper, a numerical model has been developed to study the potential of use of cylinder bore surface texturing, in the form of circumferential oil grooves with different dimensions and densities, to improve the tribological properties of piston ring–cylinder liner tribosystem. The average Reynolds equation has been employed in the area of microscale texture and the effect of macroscale grooves has been incorporated to improve the currently lubrication model. The focus is put on cavitation formation condition and boundary condition in grooves within the area of lubrication, analysis of the effect of macrogroove dimension characters and distribution of grooves on the tribological performance of piston compression ring. The solution provides the hydrodynamic friction force, boundary friction force, coefficient of friction, and the total friction force. The results show that the cylinder liner oil grooves can efficiently be used to maintain hydrodynamic effect. It is also shown that optimum surface texturing may substantially reduce the friction losses between piston ring and cylinder liner.

A Matching Method for Two-Stage Turbocharging System

The turbine system of a two-stage turbocharger composed of high pressure turbine (HT), low pressure turbine (LT), and by-pass valve decides distribution and utilization of exhaust gas energy and influence performance of two-stage turbocharger in whole operational conditions. Besides, characteristics of turbine is expressed by envelop line of characteristic lines in different speeds. So turbine can be conveniently selected compared with compressor with similarity theory. Therefore, two-stage turbocharger matching begins from turbine system matching in the paper. In two-stage turbocharger, cooler efficiency, cooler loss, and by-pass valve open besides turbochargers will influence turbocharging system performance and design of cooler and by-pass valve are important contents of turbocharging system matching. The paper matched intercooler, by-pass valve open, compressors, and turbines jointly. Calculation model for turbocharger matching was built, and turbine performance is get from reference turbine based on similarity theory; influence of compressor ratio distribution, cooler efficiency, and pressure drop in cooler imposing on compressor work was analyzed; and influence of turbine flow capacity and by-pass valve imposing on output working in expanding process was studied; the method for matching of two-stage turbocharging system in whole operational condition is studied. Matching analysis was made aiming at two-stage turbocharging system of a type of high power density diesel engine, and design for turbocharging system was finished. Matching result using the method is compared to matching result using traditional method. Analysis result proves that using the method matching points in different operational conditions are located in more reasonable zone of compressor MAP.

Improving Tribological Behavior of 2-Stroke Marine Diesel Engine Piston Ring by Cylinder Liner Surface Texturing

Piston ring lubrication in some types of low-speed 2-stroke marine diesel engines is completely different from those in medium-or high-speed diesel engines since the inner surface of cylinder liners are textured with circular grooves in macro-scale and honing texture in micro-scale. In this paper, a numerical model has been developed to study the potential of use of cylinder bore surface texturing, in the form of circumferential oil grooves with different dimensions and densities, and their efficiency to improve the tribological properties of piston ring-cylinder liner tribo-system. The average Reynolds equation has been employed in the area of micro-scale texture and the effect of macro-scale grooves has been incorporated to improve the currently lubrication model. The results showed that the cylinder liner oil grooves can efficiently be used to maintain hydrodynamic effect. It is also shown that optimum surface texturing may substantially reduce the friction losses between piston ring and cylinder liner.