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…
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…
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 …
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, [7] and [13]. 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.…
