Qaisar Hayat

Research on key factors and their interaction effects of electromagnetic force of high-speed solenoid valve.

Analysis consisting of numerical simulations along with lab experiments of interaction effects between key parameters on the electromagnetic force based on response surface methodology (RSM) has been also proposed to optimize the design of high-speed solenoid valve (HSV) and improve its performance. Numerical simulation model of HSV has been developed in Ansoft Maxwell environment and its accuracy has been validated through lab experiments. Effect of change of core structure, coil structure, armature structure, working air gap, and drive current on the electromagnetic force of HSV has been analyzed through simulation model and influence rules of various parameters on the electromagnetic force have been established. The response surface model of the electromagnetic force has been utilized to analyze the interaction effect between major parameters. It has been concluded that six interaction factors including working air gap with armature radius, drive current with armature thickness, coil turns with side pole radius, armature thickness with its radius, armature thickness with side pole radius, and armature radius with side pole radius have significant influence on the electromagnetic force. Optimal match values between coil turns and side pole radius; armature thickness and side pole radius; and armature radius and side pole radius have also been determined.

Study of the fluctuation in the cycle fuel injection quantity in a common-rail system for a heavy-duty vehicle diesel engine

A common-rail system can satisfy both diesel engine emissions legislation and fuel economy by flexibly regulating the injection pressure, the injection timing, the injection duration and the injection rate. Variations in the parameters of the common-rail system influence the injection characteristics and lead to fluctuation in the cycle fuel injection quantity. This fluctuation in the cycle fuel injection quantity is very critical for the coherence and stability of the common-rail system and the diesel that it injects. A new numerical model of a diesel engine’s common-rail system was developed in AMESim to investigate the cycle fuel injection quantity fluctuation. The predicted results of the rail pressure and the injection rate by the model are in excellent agreement with the experimental results obtained from a test bench. The influence law and the generation mechanism of the cycle fuel injection quantity fluctuation caused by variations in the different parameters are analysed in detail. Moreover, the quantitative percentages of fluctuation in the cycle fuel injection quantity are computed through analysis. The results show that the solenoid pre-tightening force, the orifice diameter of the outlet, the orifice diameter of the inlet and the needle lift are the four critical influential parameters of the common-rail system. Finally, a correlation analysis method was carried out on the cycle fuel injection quantity. The analysis results show that not only the first-order factors of the influential parameters but also the second-order factors which consider the interaction between the influential parameters have significant correlation with the cycle fuel injection quantity.

Nonlinear Modeling and Analysis of Pressure Wave inside CEUP Fuel Pipeline

Operating conditions dependent large pressure variations are one of the working characteristics of combination electronic unit pump (CEUP) fuel injection system for diesel engines. We propose a precise and accurate nonlinear numerical model of pressure inside HP fuel pipeline of CEUP using wave equation (WE) including both viscous and frequency dependent frictions. We have proved that developed hyperbolic approximation gives more realistic description of pressure wave as compared to classical viscous damped wave equation. Frictional effects of various frequencies on pressure wave have been averaged out across valid frequencies to represent the combined effect of all frequencies on pressure wave. Dynamic variations of key fuel properties including density, acoustic wave speed, and bulk modulus with varying pressures have also been incorporated. Based on developed model we present analysis on effect of fuel pipeline length on pressure wave propagation and variation of key fuel properties with both conventional diesel and alternate fuel rapeseed methyl ester (RME) for CEUP pipeline.

D6114 diesel engine speed control: A case between PID controller and fuzzy logic controller

The engine speed controller of a conventional diesel engine is called a Governor. In order to control engine speed, the governor controls the amount of fuel using fuel rack. This study presents a development of speed control of D6114 diesel engine by using PID controller and a self-tuning fuzzy PID controller to overcome the appearance of nonlinearities and uncertainties in the systems. The self-tuning fuzzy PID controller is the combination of a classical PID and fuzzy controller. The mathematical model of the diesel engine is also done by using System Identification technique. First, PID controller was applied; then, a fuzzy logic control algorithm is used to estimate the PID coefficient in order to handle such uncertainties to produce a better control performance. Simulation tests were established using Simulink of Matlab. The obtained results have demonstrated the feasibility and effectiveness of the proposed fuzzy approach comparing to the PID controller. Simulation results are represented in this study.

Pressure Modeling of Combination Electronic Unit Pump Fuel Pipeline with Rapeseed Methyl Ester

An alternate biodiesel fuel Rapeseed Methyl Ester (RME) has been evaluated for diesel engine Combination Electronic Unit Pump (CEUP) fuel injection system. Pressure wave modeling of CEUP high pressure fuel pipeline using viscous damped wave equation has been done in MATLAB at various operating conditions of diesel engine. Finite Difference method has been used to model and simulate wave equation at eleven equidistant locations along fuel pipeline. Results show increase in pressure, density, acoustic wave speed and bulk modulus amplitudes with RME fuel as compared to conventional diesel fuel.

Tuning of PID controller of synchronous generators using genetic algorithm

Control of synchronous generators such as automatic voltage regulators have been developed to maintain stability and to improve damping of power systems. When an operating condition changes greatly, however, such controllers may become less effective because of nonlinearity of the power system. The mathematical model of AVR system has been established for control and analysis using a flexible and fast tuning method based on genetic algorithm (GA) technique. Tuning with different population size and generations number have been used to determine the optimal values of the PID controller parameters to improve the transient response of the system.