Introduction to Experimental Cells for Diesel Spray Research
The study of the combustion process in Diesel engines has been going even deeper into depth with the application of new techniques of measure and more rigorous methodologies. This has taken into new expectations in the development of parametric studies and in the construction of tools (physical models or experimental setup) that allow the reproduction of similar thermodynamic conditions to the ones present in the inside of a cylinder in a real thermal engine, making it possible to obtain greater approximations between the theoretical relation and the experimental one. Experimental setup classification The physical models or experimental setup used to study the injection-combustion process usually are of very specific characteristics, depending on the phenomena to analyse. These models can be classified in the three following groups: According to the type of the working fluid -Models with cold working fluid are used to study sprays in non-evaporating conditions, but many times in conditions similar to the existing ones in a real thermal engine. - Models with hot working fluid, this kind of model is the best way to study sprays in evaporating conditions and in the majority of times it’s possible to simulate a real …
Introduction to Liquid Sprays Characteristics in Diesel Engines
For decades, the process of injecting an active fluid (diesel fuel) into the thermodynamic behaviour of a working fluid (air or gas) has been a priority in the research of the phenomena that occur in combustion systems. Due to technological improvements it’s possible in present times to characterise the injection fuel process in such conditions that match those happening when the engine is running under standard conditions, hence the purpose of these studies, which focus in the achievement of a perfect mixture between the working and active fluids; as a result of this, a series of consequences are triggered that lead to an optimum combustion, and therefore in the improvement of the engines capabilities. In Diesel engines the combustion process basically depends on the fuel injected into the combustion chamber and its interaction with the air. The injection process is analysed from this point of view, mainly using as basis the structure of the fuel spray in the combustion chamber, making this study of high importance for optimizing the injection process, and therefore reducing the pollutant emissions and improving the engines performance. Because of these, the importance to obtain the maximum control of the diesel spray structure using electronic control systems has become vital. To reduce pollutant emissions and achieving a high engine performance, it’s necessary to know which parameters influence these ratings the most. It is consider being several meaningful factors that have an influence, but the most important one is the diesel spray, more specifically the penetration of the liquid length of the spray thru the combustion chamber or piston bowl. The analysis of the liquid length penetration is very useful to determine the geometric design of high speed Diesel engine combustion chambers with direct injection. For example, in a low speed regime and light load conditions, the unburned hydrocarbon emissions will be reduced greatly if contact between the spray of fuel (liquid length) and the combustion chamber wall is avoided. If now we consider a high speed regime and heavy load, the emission of fumes is reduced if there is contact between the spray of fuel and the combustion chamber wall, hence the importance of measuring the liquid phase penetration of the fuel in Diesel engines with direct injection, using sophisticated and complex measuring techniques. Diesel spray characteristics Depending on the mechanism to characterise, diesel spray can be analysed in a macroscopic or microscopic point of view. With the purpose of understanding in detail this process, the various physical parameters involved during the transition of a pulsed diesel spray will be expressed in this chapter, however it is essential to know the systems that make possible for…
Introduction to Gasoline direct injection
The basic goals of the automotive industry; a high power, low specific fuel consumption, low emissions, low noise and better drive comfort. With increasing the vehicle number, the role of the vehicles in air pollution has been increasing significantly day by day. The environment protection agencies have drawn down the emission limits annually. Furthermore, continuously increasing price of the fuel necessitates improving the engine efficiency. Since the engines with carburetor do not hold the air fuel ratio close to the stoichiometric at different working conditions, catalytic converter cannot be used in these engines. Therefore these engines have high emission values and low efficiency. Electronic controlled Port Fuel Injection (PFI) systems instead of fuel system with carburetor have been used since 1980’s. In fuel injection systems, induced air can be metered precisely and the fuel is injected in the manifold to air amount. By using the lambda sensor in exhaust system, air/fuel ratio is held of stable value. Fuel systems without electronic controlled it is impossible to comply with the increasingly emissions legislation. If port fuel injection system is compared with carburetor system, it is seen that has some advantages. These are; 1. Lower exhaust emissions. 2. Increased volumetric efficiency and therefore increased output power and torque. The carburetor venturi prevents air and, in turn, volumetric efficiency decrease. 3. Low specific fuel consumption. In the engine with carburetor, fuel cannot be delivered…
Introduction to Hardware-in-Loop Simulation Technology of High-Pressure Common-Rail Electronic Control System for Low-Speed Marine Diesel Engine
Oil price is increasing rapidly due to the oil reserve limited as a non-renewable resource. The proportion of the fuel cost rises in the total operating costs of ocean transportation…
Introduction to Model-Based Condition and State Monitoring of Large Marine Diesel Engines
Although the history of diesel engines extends back to the end of the nineteenth century and in spite of the predominant position such engines now hold in various applications, they are still subject of intensive research and development. Economic pressure, safety critical aspects, compulsory onboard diagnosis as well as the reduction of emission limits lead to continuous advances in the development of combustion engines. Condition monitoring and fault diagnosis represent a valuable set of methods designed to ensure that the engine stays in good condition during its lifecycle, and . Diagnosis in the context of diesel engines is not new and various approaches have been proposed in the past years, however, recent technical and computational advances and environmental legislation have stimulated the development of more efficient and robust techniques. In addition, the number of electronic components such as sensors or actuators and the complexity of engine control units (ECUs) are steadily increasing. Meanwhile, most of the software running on the main ECU is responsible for condition monitoring of sensor signals, monitoring parameter ranges, detecting short/open circuits, and verifying control deviations. However, these kinds of condition monitoring systems (CMS) are not designed to detect and clearly identify different engine failures, sensor drifts and to predict developing failures, i.e. to asses degradation of certain components right in time. Especially the reliable detection and separation of engine malfunctions is of major importance in various fields of industry in order to predict and to plan maintenance intervals. Diesel engines usually consist of a fuel injection system, pistons, rings, liners, an inlet and exhaust system, heat exchangers, a lubrication system, bearings and an ECU. For the design of an efficient CMS it is essential to know as much as possible about the underlying thermodynamical processes and possible faults and malfunctions. This information can be seen as a-priori knowledge and can be used to increase the robustness of fault detection algorithms. In the following, common diesel engine faults and fault mechanisms, and their causes are listed. • power loss caused by misfire and blow-by. • emission change caused by loss of compression, turbocharger malfunction, blocked fuel filter, incorrect injector timing, poor diesel fuel, incorrect fuel air ratio, air intake filter blocked, incorrect piston topping, or ECU malfunction etc. • lubricating system fault due to incorrect oil pressure and oil deterioration • thermal overload as a result of one or a combination of leaking injection valves, piston ring-cylinder wear or failure, eroded injector holes, too low injection pressure, high engine friction, misfire, leaking intake or exhaust manifold/valves, high coolant or lubricant temperature etc. • leaks in the fuel injection system, lubrication system, or air intake • wear of the piston caused by either corrosion or abrasion, or both • noise and vibration caused by the impact of one engine part against another (mechanical noise), vibrations resulting from combustion, intake and exhaust noise • other faults like knocking, filter faults, fuel contamination and aeration The main challenge in engine fault detection is the ambiguity between faults and causes. Certain engine faults may be caused by a combination of causes (with different weightage). The assessment of engine states from sparse measurement data as well as a reliable assignment of failure effects and causes are an active research field. The problems relating to marine diesel engines, especially medium- and high-speed engines, are due mainly to their large size and…
Introduction to Design and Field Tests of a Digital Control System to Damping Electromechanical Oscillations Between Large Diesel Generators
Electromechanical oscillations are natural phenomena in power systems having two or more synchronous generating units operating interconnected. These oscillations are undesirable because they can severely limit the power transfer between…
Introduction to NOx Storage and Reduction forDiesel Engine Exhaust Aftertreatment
Diesel and lean-burn engines provide better fuel economy and produce lower CO2 emissions compared to conventional Otto gasoline engines. However, the NOx gas components in the lean (oxidizing) exhausts from diesel and…
Introduction to Optimization of Diesel Engine with Dual-Loop EGR by Using DOE Method
The diesel engine has advantages in terms of fuel consumption, combustion efficiency and durability. It also emits lower carbon dioxide (CO2), carbon monoxide(CO) and hydrocarbons(HC). However, diesel engines are the…
Introduction to Structured Catalysts for Soot Combustion for Diesel Engines
During the last decade, diesel engines have increased in popularity compared to gasoline engines because of their superior fuel economy, reliability and durability, simultaneously associated with a favorable fuel tax…
Introduction to Analytical Methodologies for the Control of Particle-Phase Polycyclic Aromatic Compounds from Diesel Engine Exhaust
Diesel emissions contain complex mixtures of chemical constituents that are known to be (or possibly to be) human carcinogens, or that have adverse health effects . Among these substances (formaldehyde,…
