Cycle Diesel Engine Research Articles

Soot particle sizing during high-pressure Diesel spray combustion via time-resolved laser-induced incandescence

Single-pulse time-resolved laser-induced incandescence (TiRe-LII) signal transients from soot particulates were acquired during unsteady high pressure Diesel combustion in a constant volume cell for typical top dead center conditions during a Diesel engine cycle. Measurements were performed for initial gas pressures between 1 and 3 MPa, injection pressures between 50 and 130 MPa and laser probe timings between 5 and 16 ms after start of fuel injection. In separate experiments and for the same cell operating conditions gas temperatures were deduced from spectrally resolved soot pyrometry measurements. Implementing the LII model of Kock et al. [Combust. Flame 147 (2006) 79–92] ensemble mean soot particle diameters were evaluated from least-squares fitting of theoretical cooling curves to experimental TiRe-LII signal transients. Since in the experiments the environmental gas temperature and the width of an assumed particle size distribution were not known, the effects of the initial choice of these parameters on retrieved particle diameters were investigated. It is shown that evaluated mean particle diameters are only slightly biased by the choice of typical size distribution widths and gas temperatures. For a fixed combustion phase mean particle diameters are not much affected by gas pressure, however they become smaller at high fuel injection pressure. At a mean chamber pressure of 1.39 MPa evaluated mean particle diameters increased by a factor of two for probe delays between 5 and 16 ms after start of injection irrespective of the choices of first-guess fitting variables, indicating a certain robustness of data analysis procedure.

Experimental and Theoretical Investigation of the Effects of Gasoline Blends on Single-Cylinder Diesel Engine Performance and Exhaust Emissions

The present study investigates experimentally and theoretically the effects of using of gasoline−diesel fuel blends on single-cylinder diesel engine performance and exhaust emissions. The study consists of two parts: (i) Experimental study: The effects of using of different gasoline−diesel fuel blends have been investigated experimentally and compared in a single-cylinder diesel engine. In this part, the effects of 2−10% gasoline blends have been investigated experimentally in a single-cylinder diesel engine at the speeds of 900−1600 rpm and at the selected compression ratios of 18−23. (ii) Theoretical study: A computer program has been developed for the prediction of diesel engine cycles and engine characteristics for the cases of neat diesel fuel (NDF) and gasoline−diesel fuel blends. For calculation of the diesel engine cycle, a quasi-dimensional phenomenological combustion model developed by Shahed and then improved by Ottikkutti has been used and modified with new assumptions. After the engine cycle ...

Combustion characteristics of a closed cycle diesel engine with different intake gas contents

This paper is to carry out a numerical simulation of combustion characteristics for a closed cycle diesel engine (CCDE) with different intake gas contents under different engine speeds and equivalence ratios. The numerical simulation used Kiva3V-Release2 code as the main program by modifying some subroutines containing different intake gas contents of oxygen, argon, and nitrogen and their thermodynamic properties. The results show that the pressure will increase earlier if the percentage of argon is higher when we use argon to replace nitrogen, and the ignition delay will be shorter, too. The higher in-cylinder temperature results from a higher concentration of argon.

Desempenho de motor ciclo Diesel em bancada dinamométrica utilizando misturas diesel/biodiesel

Diante da previsão de escassez do petróleo, o éster etílico (biodiesel) tem-se apresentado como excelente opção de combustível alternativo para motores ciclo Diesel. As características do biodiesel são semelhantes às do diesel em termos de viscosidade e poder calorífico, podendo ser utilizado sem adaptações nos motores. Para a realização deste trabalho, utilizou-se de motor ciclo Diesel, de injeção direta, com quatro cilindros, sem adaptações. O motor foi acoplado a um dinamômetro e sistemas de aquisição de dados auxiliares. Avaliaram-se os desempenhos de torque, de potência e de consumo específico de combustível para as seguintes misturas diesel/éster etílico de soja: B2, B5, B10, B20, B50, B75 e B100. O melhor desempenho registrado deu-se com a mistura B20.

Multi-zone combustion modeling for the prediction of diesel engine cycles and engine performance parameters

In the presented study, the aim is to develop a complete cycle model and to prepare a computer code for determining complete cycle, performance characteristics, and exhaust emissions of diesel engines. For this purpose, a computer program has been developed. To compute diesel engine cycles, zero-dimensional intake and exhaust model developed by Durgun, zero-dimensional compression and expansion model given by Heywood and quasi-dimensional phenomenological combustion model developed by Shahed and Ottikkutti have been used and developed with new assumptions. The combustion model is based on a multi-zone combustion modeling concept. Details of fuel spray formation, fuel–air mixing, swirl and heat transfer have been taken into account in this model. Also, an emission model based on the chemical equilibrium and kinetics of NO has been developed to calculate the pollutant concentrations within each zone and the whole of the cylinder. Using the developed computer program, complete engine cycle, engine performance parameters and exhaust emissions can be determined easily. The values of the cylinder pressure and engine performance parameters predicted by the presented model matched closely with the other theoretical models and experimental data. Also, this program can be adapted and used practically for various parametric and alternative fuel studies.

Amostragem do material particulado e fração orgânica volátil das emissões em motor ciclo diesel sem a utilização de túnel de diluição

Using a sampling method of particulate matter (PM) without the use of a dilution tunnel allows for evaluations of the volatile hydrocarbons (HC) in the emissions of diesel cycle engines. The procedure in this work applied a heated filter with temperature controlled. The volatile compounds are condensed at low temperature, allowing for evaluation of the HC by thermal desorption of the PM and for analysis of the condensed compounds of the exhaust gases.

舶用燃料油における着火および燃焼特性の評価―光学的燃焼特性試験装置による実験的評価

Nowadays, low-speed two-stroke cycle diesel engines are used for marine transportation because of their high thermal efficiency, thus utilizing cheap fuel, of course good from the economical viewpoint. However, some marine diesel engines have been damaged when low grade bunker oil is used. Here, ignitability and combustibility of 107 samples of bunker fuel oil was evaluated. Visualization via a high-speed color video camera was conducted with signals of photo-sensors, rate of heat release and analysis of fuel properties. It was found that ignition delay and after-burning do differ, fuel to fuel. By changing the gas temperature at injection time, the degree of ignitability for the sample fuel could be clearly judged. Short or long after-burning was shown in spite of the same ignition delay. In some fuel oils, the combustion was promoted after ignition, even if the ignition delay was long. Some fuel oils, those with low sulfur content of less than 1.0%, and a higher nitrogen content with a CCAI value between 840 and 860, presented both worse ignitability and worse combustibility. However, on the other hand, some fuel oils showed good combustibility, even in these properties. Therefore, this equipment will be a strong tool to judge the fuel quality of combustion before bunkering fuel oil.

Theoretical investigation of effects of light fuel fumigation on diesel engine performance and emissions

In the presented study, the effects of light fuel fumigation on the diesel engine cycle and characteristics have been examined theoretically. For this purpose, a computer program has been developed for prediction of the diesel engine cycle and engine characteristics in the cases of neat diesel fuel (NDF) and light fuel (LF) fumigation. Here, ethanol is used as the fumigating (supplementary) light fuel. For calculation of the diesel engine cycle, the quasi-dimensional phenomenological combustion model developed by Shahed and then Ottikkutti has been used and developed with new assumptions. Firstly, the accuracy of the developed engine cycle model for NDF and LF fumigation has been controlled by using various experimental and theoretical results. Then, the effects of 2.5–20% ethanol fumigation have been investigated at variable equivalence ratios (VER) and constant equivalence ratios (CER). It can be said that for increasing ethanol fumigation at VER, the effective power, effective efficiency and carbon monoxide (CO) ratios increase and the specific fuel consumption (SFC) and nitric oxide (NO) concentration decrease. Effective power, effective efficiency and NO concentration increase, generally, with increasing ethanol fumigation ratios at CER. In this case, SFC and CO ratio exhibits an incremental tendency generally.

High speed direct injection (DI) light-fuel (gasoline) fumigated vehicle diesel engine

In the presented study, the effects of light-fuel fumigation on diesel engine cycle and characteristics have been examined theoretically. For this purpose, a computer program has been developed for prediction diesel engine cycles and engine characteristics in the cases of neat diesel fuel (NDF) and light-fuel (LF) fumigation. Here, gasoline is used as fumigated (supplementary) light fuel. For calculation of diesel engine cycle, quasi-dimensional phenomenological combustion model developed by Shahed and then Ottikkutti has been used and developed with new assumptions. Firstly, it has been proved that the developed engine cycle model for NDF and LF fumigation gives correct results by comparing with relevant experimental and theoretical studies. Then, for selected 2–10% gasoline ratios LF fumigation is investigated at varied equivalence ratio (VER) and constant equivalence ratios (CER). As a result, it has been determined that increasing gasoline fumigation at VER effective power and carbon monoxide (CO) ratio increase however, nitric oxide (NO) concentration decreases. Also, effective efficiency and specific fuel consumption (SFC) remain nearly constant in this case. Effective power, effective efficiency and CO ratio increase generally by increasing the gasoline fumigation ratio but SFC and NO concentration decrease generally at CER. Furthermore, this case is economic at high engine speeds.

Effects of operating parameters on steady and transient behaviors of a closed cycle diesel engine

Abstract This study set out to develop the first closed cycle diesel engine (CCDE) system in Taiwan and to study the engine performance under transient and steady operation conditions. The aim of the development was to design and establish these systems, including a cooling system, a CO 2 absorbing system, a charge mixing system and an oxygen control system. The exhaust emissions CO 2 and smoke from the engine were measured and analyzed using different chemical absorbents (KOH, NaOH and Ca(OH) 2 ) in the CO 2 absorbing system under different injection pressures (155 kg/cm 2 , 185 kg/cm 2 and 200 kg/cm 2 ) and different electric powers (1 kW, 2 kW and 4 kW). KOH was found to have the best effect on the absorption of CO 2 among the three absorptive liquids (KOH, NaOH and Ca(OH) 2 ), and it achieved the lowest oscillation of oxygen at a lower electric load. The brake specific fuel consumption (bsfc) with KOH used in the CO 2 absorber was less than that for the two other absorbents. It was found that with increasing injection pressure, the concentration of smoke decreased but both CO 2 concentration and bsfc increased. The concentration of smoke increased, but the bsfc decreased as the electric load increased. The larger the electric load was, the longer it took before the oxygen concentration reached a steady state.

10106 カルノーサイクルの理解を助けるアニメーションコンテンツの開発(技術教育・工学教育(2),OS5 技術教育・工学教育)

The Carrot cycle is not heat engine which exists actually. Therefore, it is not possible to explain the principle of the Carnot cycle by the reality. In the previous report, CG animation multi-media contents which support the description of operation principle of Otto cycle and Diesel cycle engine was developed, and the learning effect was confirmed. In this paper, for the purpose of supporting to make the student understanding the principle of Carnot cycle, CG animation multi-media contents which explain the operation principle of Carrot cycle was developed.

An Analytical Study on the Mixed Lubrication of Piston Rings in a 4-Stroke Cycle Diesel Engine

An Analytical Study on the Mixed Lubrication of Piston Rings in a 4-Stroke Cycle Diesel Engine

Establishment of the mathematical model for diagnosing the engine valve faults by genetic programming

Available machine fault diagnostic methods show unsatisfactory performances on both on-line and intelligent analyses because their operations involve intensive calculations and are labour intensive. Aiming at improving this situation, this paper describes the development of an intelligent approach by using the Genetic Programming (abbreviated as GP) method. Attributed to the simple calculation of the mathematical model being constructed, different kinds of machine faults may be diagnosed correctly and quickly. Moreover, human input is significantly reduced in the process of fault diagnosis. The effectiveness of the proposed strategy is validated by an illustrative example, in which three kinds of valve states inherent in a six-cylinders/four-stroke cycle diesel engine, i.e. normal condition, valve-tappet clearance and gas leakage faults, are identified. In the example, 22 mathematical functions have been specially designed and 8 easily obtained signal features are used to construct the diagnostic model. Different from existing GPs, the diagnostic tree used in the algorithm is constructed in an intelligent way by applying a power-weight coefficient to each feature. The power-weight coefficients vary adaptively between 0 and 1 during the evolutionary process. Moreover, different evolutionary strategies are employed, respectively for selecting the diagnostic features and functions, so that the mathematical functions are sufficiently utilized and in the meantime, the repeated use of signal features may be fully avoided. The experimental results are illustrated diagrammatically in the following sections.

차량 동력 전달계의 비틀림 가진원에 관한 실험적 연구

Torque fluctuation of the engine and angular velocity variation of propeller shaft is the main excitation source for torsional vibration in the vehicle driveline. Experimental model for engine system is constructed with 4 cylinder 4 cycle diesel engine including Motor-Propeller Shaft-Axle-Wheel system. The angular velocity is measured by magnetic pickup and FV converter at the engine flywheel and propeller shaft. This paper presents the theoretical mechanism of these excitation sources and it is identified by the experimental methods.

05/00780 In cylinder expansion of ring crevice and oil film hydrocarbons in SI engines

The main purpose of the presented study is to evaluate energy balance theoretically in direct injection (DI) diesel engines at different conditions. To analyze energy balance, a zero-dimensional multi-zone thermodynamic model has been developed and used. In this thermodynamic model, zero-dimensional intake and exhaust approximations given by Durgun, zero-dimensional compression and expansion model given by Heywood and quasi-dimensional phenomenological combustion model developed by Shahed and then improved Ottikkutti have been used and developed with new approximations and assumptions. By using the developed model, complete diesel engine cycle, engine performance parameters and exhaust emissions can be determined easily. Also, by using this model energy balance can be analyzed for neat diesel fuel and for light fuel fumigation easily. In the presented study, heat balance has been investigated theoretically for three different engines and various numerical applications have been conducted. In the numerical applications two different turbocharged DI diesel engines and a naturally aspirated DI diesel engine have been used. From these numerical applications, it is determined that, what portion of available fuel energy is converted to useful work, what amount of fuel energy is lost by exhaust gases or lost by heat transfer. In addition, heat balance has been analyzed for gasoline fumigation and some numerical results have been given. Brake effective power and brake specific fuel consumption increase and brake effective efficiency decreases for gasoline fumigation for turbocharged diesel engines used in numerical applications. Combustion duration increases with increasing fumigation ratio and thus heat transfer to the walls increases. Because exhaust temperature increases, exhaust losses also increases for fumigation case.

Evaluation of Losses in a Diesel Engine Cycle and Improvement of Its Thermal Efficiency (Capabilities of Diesel Engine Combined Cycle)

The Diesel engine and gas turbine combined cycle has an ability of getting much better thermal efficiency than any other type of cycles owing to its high temperature in the heat receiving process. Increase of expansion ratio in the diesel engine cycle minimizes the exergy loss in the process connecting diesel engine cycle and gas turbine one, and leads a thermal efficiency improvement about 4%. Although disuse of charge air cooling and furthermore heating of the charge air with the exhaust gas from turbine cause reduction of specific power output, they diminish the exergy losses in the heat receiving process in the cylinder and the exhaust process from turbine, and bring an improvenment of thermal efficiency by several %. The charge air temperature rise accompanying further improvement of the combined cycle thermal efficiency, requires the development of high efficiency gas turbine, and realization of the new methods for protecting diesel engine cylinder wall to higher temperature of working gas.

Evaluation of Losses in a Diesel Engine Cycle and Improvement of Its Thermal Efficiency (Exergy Loss Reduction by Improving Turbocharger Efficiency)

The improvement of turbocharger efficiency gives only slight effect to the thermal efficiency of the diesel engine cycle, because exergy loss increase in other processes than in the turbocharger is inevitable, as long as the turbocharger is used only for supercharging. This paper describes the reason with exergy analysis, and takes another look at the turbocompoud system to take out power with power turbine. The turbocompound system makes it possible to effectively use all of surplus power of the turbine, more than to drive the blower of the turbocharger. The higher the turbocharger efficiency is, the more the output power of power turbine increases and the less the cycle total exergy loss becomes.

Exergy analysis of a diesel engine cycle and its performance improvement

This paper aims to evaluate available energy losses, i.e. exergy losses caused by irreversible processes in the theoretical cycle of two-stroke and four-stroke diesel engines. All exergy losses in these cycles have been divided into three categories: exergy loss in the heat receiving process which is inevitable in thermal power systems; exergy loss in the scavenging process peculiar to the turbocharged diesel engine cycle; heat loss dissipated with the exhaust gas and the cooling water. The quantity of each exergy loss was distinctly expressed with the corresponding area in the T-s diagram. The thermal efficiency of the cycle is improved by reducing the exergy losses in each process. Turbocharging is effective not only in increasing power, but also in reducing the exergy loss. The distribution of exergy losses of two-stroke and four-stroke cycles are different to each other.

MATHEMATICAL MODEL OF COMBINED PARAMETRICAL ANALYSIS OF IN INDICATOR PROCESS AND THERMAL LOADING ON THE DIESEL ENGINE PISTON

In the publication the methodical aspects of a mathematical model of the combined parametrical analysis of an indicator process and thermal loading on the diesel engine piston have been considered. A thermodynamic model of a diesel engine cycle is developed. The executed development is intended for use during researches and on the initial stages of design work. Its realization for high revolution diesel engines of perspective type CHN15/15 allowed to choose rational variants for the organization of an indicator process and to prove power ranges of application for not cooled and created cooled oil welded pistons.

A New Hybrid Approach for the Thermo-acoustic Modelling of Engine Exhaust Systems

The time-domain method of characteristics and the frequency-domain linear acoustics method are the two different methods of thermo-acoustic modelling of engine exhaust systems in order to predict exhaust noise. To overcome the disadvantages of both the time-domain and the frequency-domain approaches, a hybrid approach has been developed which couples the acoustical description of the muffler piping system to the acoustic source more realistically than the usual time invariant linear model. A time domain model and the corresponding frequency domain model of a linear dynamical system are interrelated by the Fourier transform pair. In the present work, the cylinder/cavity is analysed in the time domain to calculate exhaust mass flux history at the exhaust valve by means of the method of characteristics, solving a number of equations simultaneously at the valve junction. This analysis has been done by making use of an interrelationship between progressive wave variables of linear acoustic theory and those of the method of characteristics. In this approach, nonlinear propagation in the exhaust pipe is neglected and radiation impedance at the end of the exhaust tail pipe is duly taken into account. Apart from this, actual reflection of the forward wave due to the presence of muffler is incorporated to make the analysis more realistic. Damping effects present in the fluid have also been taken into account. Computational results have been corroborated by experimental data for a single-cylinder, four-stroke cycle diesel engine.