Diesel Engine Speed Research Articles

Research on H2 speed governor for diesel engine of marine power station

The frequency stability of a marine power system is determined by the dynamic characteristic of the diesel engine speed regulation system in a marine power station. In order to reduce the effect of load disturbances and improve the dynamic precision of a diesel engine speed governor, a controller was designed for a diesel engine speed regulation system using H2 control theory. This transforms the specifications of the system into a standard H2 control problem. Firstly, the mathematical model of a diesel engine speed regulation system using an H2 speed governor is presented. To counter external disturbances and model uncertainty, the design of an H2 speed governor rests on the problem of mixed sensitivity. Computer simulation verified that the H2 speed governor improves the dynamic precision of a system and the ability to adapt to load disturbances, thus enhancing the frequency stability of marine power systems.

MARINE DIESEL ENGINE GOVERNOR IDENTIFICATION

The paper deals with marine diesel engine governor identification in normal and faulty operating conditions, using simulation method within real ship's propulsion plant simulator Kongsberg ERS-L11 MAN B&W-5L90MC-VLCC Version MC90-IV. Most of marine diesel engine speed controllers developed use the PID control algorithm. PID controller parameters values: gain, integral and derivate constant, are set according to the nature and dynamic characteristics of the controlled process. These values determine the system response quality, i.e. control system quality.Determination of engine governor faults effects on system behavior and system stability was of special interest in this work.

Effects of Diesel Engine Speed and Water Content on Emission Characteristics of Three-Phase Emulsions

The effects of water content of three-phase emulsions and engine speed on the combustion and emission characteristics of diesel engines were investigated in this study. The results show that a larger water content of water-in oil (W/O) and oil-in-water-in-oil (O/W/O) emulsion caused a higher brake specific fuel consumption (bsfc) value and a lower O2, as well as a lower NOx emission, but a larger CO emission. The increase in engine speed resulted in an increase of bsfc, exhaust gas temperature, fuel-to-air ratio, CO2 emission and a decrease of NOx, CO emission, and smoke opacity. Because of the physical structural differences, the three-phase O/W/O emulsions were observed to produce a higher exhaust gas temperature, a higher emulsion viscosity and a lower CO emission, in comparison with that of the two-phase W/O emulsion. In addition, the use of W/O emulsions with water content larger than 20% may cause diesel engines to shut down earlier than those running on O/W/O emulsions with the same water content. Hence, it is suggested that the emulsions with water content larger than 20% are not suitable for use as alternative fuel for diesel engines.

Diesel engine speed control with handling of driveline resonances

A vehicular driveline transfer engine torque to the wheels. Resonances in the elastic parts of the driveline are important to handle when control of the engine and the transmission is optimized. Traditional diesel engine speed control maintains a well-damped engine speed set by the driver. However, the resonance modes of the driveline are easily excited by accelerator-position changes or by road disturbances. A speed-control strategy is proposed that includes the behavior of the driveline, and reduces driveline resonances and vehicle shuffle by engine control. Implementation shows significant reduction, also when facing nonlinear torque limitations from maximum torque and diesel smoke delimiters.

Diesel-Engine Speed Control with Handling of Driveline Resonances

A vehicular driveline transfer engine torque to the wheels. Resonances in the elastic parts of the driveline are important to handle when control of the engine and the transmission is optimized. Traditional diesel engine speed control maintains a well damped engine speed set by the driver. However, the resonance modes of the driveline are easily excited by accelerator-position changes or by road disturbances. A speed-control strategy is proposed that includes the behavior of the driveline, and reduces driveline resonances and vehicle shuffle by engine control. Implementation shows significant reduction, also when facing nonlinear torque limitations from maximum torque and diesel smoke delimiters.

Dynamic characteristics of autonomous wind–diesel systems

In this paper the dynamics of a small autonomous system, comprising a diesel generator and a wind turbine, are investigated. The analysis is performed both in the frequency and time domain, using simplified models of the system components and taking into account the diesel engine speed governor and the wind turbine pitch controller (for pitch regulated machines). The investigation is extended to include different types of wind turbines, equipped with induction or synchronous generator and using pitch or stall regulation, as well as operation of the wind turbine in an autonomous or infinite system. The objective is to determine the main factors affecting the behaviour of the system and to illustrate the effect of the speed governor and pitch controller settings on the expected performance. Particular emphasis is placed on identifying the main modes of the system and determining their dependence on the controllers' parameters. A comparative assessment of the dynamic characteristics of different types of wind turbines is also included and the operation of the wind turbine in a small system and against an infinite bus is addressed and discussed.