scholarly journals A Study on the Effects of Plug Shape on Operating Performance of an Electric Pressure Regulator Applied for Gaseous Fueled Vehicles

2021 ◽  
Vol 31 (2) ◽  
pp. 84-91
Keyword(s):  
Dynamic Response ◽  
Mathematical Models ◽  
Electromagnetic Force ◽  
Operating Performance ◽  
Slope Angle ◽  
Symmetric Model ◽  
Two Dimensional ◽  
Pressure Regulator ◽  
Simulation Results ◽  
Electric Pressure

A model-based study was conducted to examine the effects of plug shape on electromagnetic force and dynamic response of an electric pressure regulator (EPR) applied for gaseous fueled vehicles. Mathematical models were established to describe the operation of the EPR, including mechanical and electrical models. A two-dimensional (2D) symmetric model of the EPR was built in Maxwell software to simulate the electromagnetic force under the effects of plug shape. Afterward, the 2D symmetric model of EPR with the electromagnetic force calculated was imported into Simplorer software to simulate the dynamic response of the EPR based on the influence of plug shape. The shape of plug in the EPR was changed through the dimension parameters denoted by dimension (h) and slope angle (). The simulation results show that the electromagnetic force and dynamic response of the EPR can be optimized when h and  are selected at 3mm and 480, respectively.

Effects of working conditions on the operating characteristics of an injection system applied on CNG fueled vehicles

2021 ◽  
pp. 095440702110694
Author(s):  
Nguyen Ba Hung ◽  
Le Anh Tuan ◽  
Ocktaeck Lim
Keyword(s):  
Fuel Injection ◽  
Gas Pressure ◽  
Injection System ◽  
Fuel Injection System ◽  
Operating Characteristics ◽  
Pressure Regulator ◽  
Maximum Fluctuation ◽  
Coil Resistance ◽  
Simulation Results ◽  
Electric Pressure

A model-based study is conducted to examine the operating characteristics of an injection system applied on CNG fueled vehicles. This injection system is a combination of an electric pressure regulator, a rail tube, and a solenoid injector. The electric pressure regulator has a great potential to be widely used in injection systems of natural gas-fueled engines due to its flexible operation, which can help to improve the engine performance and reduce emission. This paper presents a simulation study using mathematical models to describe and analyze the operating characteristics of the gaseous fuel injection system, in which models of electric pressure regulator, solenoid fuel injector, and control model for electric pressure regulator are presented. The simulation results are compared with experimental data to validate the simulation models. Effects of working conditions, including coil resistance of the electric pressure regulator, inlet gas pressure, and set pressure in the rail tube, on the operating characteristics of the gaseous fuel injection system are investigated. Simulation results show that when the coil resistance of the electric pressure regulator is increased from 3.1 Ω to 4.1 Ω, the maximum fluctuation of the controlled gas pressure in the rail tube is reduced from 0.017 to 0.012 MPa, respectively. By decreasing the inlet gas pressure of the electric pressure regulator from 2.5 to 2.3 MPa, the controlled gas pressure in the rail tube is more stable with the maximum fluctuation significantly reduced from 0.012 to 0.002 MPa, respectively, which leads to stability in injection flow rate. The increase of set pressure in the rail tube from 0.5 to 0.7 MPa can help to improve the stability of the controlled gas pressure in the rail tube with the maximum fluctuation respectively reduced from 0.002 to 0.001 MPa.

scholarly journals Development of a High-Performance Electric Pressure Regulator Applied for Compressed-Natural-Gas-Fueled Vehicles

2020 ◽  
Vol 12 (19) ◽  
pp. 7938
Author(s):  
Nguyen Ba Hung ◽  
Ocktaeck Lim
Keyword(s):  
Natural Gas ◽  
Electromagnetic Force ◽  
High Performance ◽  
Computational Cost ◽  
Pressure Regulator ◽  
Compressed Natural Gas ◽  
Operational Characteristics ◽  
Maxwell Models ◽  
Gas Fueled ◽  
Electric Pressure

A model-based study is carried out based on a combination of mathematical and Maxwell models to develop a high-performance electric pressure regulator utilized for compressed-natural-gas-fueled vehicles. To reduce computational cost, a symmetric two-direction model of the electric pressure regulator is established in Maxwell software, in which its material properties and dimension parameters are obtained on the base of specifications of a real electric pressure regulator. The output of simulating in Maxwell is the electromagnetic force, which is significantly improved when changing core shape in the various dimensions ∆1, ∆2, and ∆3. The optimal electromagnetic force is utilized for the mathematical models as an input variable to simulate the operational characteristics of the electric pressure regulator such as displacement and response time of plunger. The operational characteristics of the electric pressure regulator are examined under the influences of key parameters, including inlet gas pressure, diameter of orifice, and spring stiffness. By optimizing these key parameters, the simulated results in this study show that an electric pressure regulator with high performance can be obtained.

Application of Self-Calibration in Flatness Assessment

2012 ◽  
Vol 605-607 ◽  
pp. 1054-1057
Author(s):  
Tian Tai Guo ◽  
Xiao Xiao Wang ◽  
Hui Zou ◽  
Bo Hong ◽  
Jun Zhao ◽  
...  
Keyword(s):  
Mathematical Models ◽  
The Self ◽  
Measurement Noise ◽  
Calibration Error ◽  
Two Dimensional ◽  
Random Measurement ◽  
Self Calibration ◽  
Calibration Algorithm ◽  
Simulation Results ◽  
Flatness Error

A self-calibration algorithm is described that allows the separation of the flatness error of two-dimensional profiling stages through the combination with a flat artifact whose accuracy is unknown. The calibration requires performing three independent measurements with different orientations of the same artifact to make mathematical models. Then the self-calibration algorithm was simulated using Matlab. The simulation results show that when there is no random measurement noise, this algorithm can realize exact calibration of the flatness error of the stage, while in the presence of random measurement noise, the algorithm introduces a calibration error of about the same size as the random measurement noise itself.

Design of finite-time guidance law based on observer and head-pursuit theory

2021 ◽  
pp. 095441002098456
Author(s):  
Chenqi Zhu
Keyword(s):  
Finite Time ◽  
Three Dimensional ◽  
Hypersonic Vehicle ◽  
Two Dimensional ◽  
Dimensional Model ◽  
Reaching Law ◽  
Guidance Law ◽  
Fast Power ◽  
Simulation Results ◽  
Guidance Laws

In order to improve the guiding accuracy in intercepting the hypersonic vehicle, this article presents a finite-time guidance law based on the observer and head-pursuit theory. First, based on a two-dimensional model between the interceptor and target, this study applies the fast power reaching law to head-pursuit guidance law so that it can alleviate the chattering phenomenon and ensure the convergence speed. Second, target maneuvers are considered as system disturbances, and the head-pursuit guidance law based on an observer is proposed. Furthermore, this method is extended to a three-dimensional case. Finally, comparative simulation results further verify the superiority of the guidance laws designed in this article.

Dynamics Simulation and Analysis of Transition Stage of Tilt-Rotor Aircraft

2016 ◽  
Vol 842 ◽  
pp. 251-258 ◽  
Author(s):  
Muhammad Rafi Hadytama ◽  
Rianto A. Sasongko
Keyword(s):  
Dynamic Response ◽  
Equations Of Motion ◽  
Flight Dynamics ◽  
Dynamics Simulation ◽  
Tilt Rotor ◽  
Vertical Takeoff And Landing ◽  
Improved Stability ◽  
Simulation Results ◽  
Vtol Aircraft ◽  
Vertical Takeoff

This paper presents the flight dynamics simulation and analysis of a tilt-rotor vertical takeoff and landing (VTOL) aircraft on transition phase, that is conversion from vertical or hover to horizontal or level flight and vice versa. The model of the aircraft is derived from simplified equations of motion comprising the forces and moments working on the aircraft in the airplane's longitudinal plane of motion. This study focuses on the problem of the airplane's dynamic response during conversion phase, which gives an understanding about the flight characteristics of the vehicle. The understanding about the flight dynamics characteristics is important for the control system design phase. Some simulation results are given to provide better visualization about the behaviour of the tilt-rotor. The simulation results show that both transition phases are quite stable, although an improved stability can give better manoeuver and attitude handling. Improvement on the simulation model is also required to provide more accurate and realistic dynamic response of the vehicle.

Direct simulation of evolution and control of three-dimensional instabilities in attachment-line boundary layers

1995 ◽  
Vol 291 ◽  
pp. 369-392 ◽  
Author(s):  
Ronald D. Joslin
Keyword(s):  
Boundary Layer ◽  
Stokes Equations ◽  
Three Dimensional ◽  
Plate Boundary ◽  
Navier Stokes ◽  
Two Dimensional ◽  
Computationally Efficient ◽  
Simulation Results ◽  
Dimensional Simulation ◽  
Attachment Line

The spatial evolution of three-dimensional disturbances in an attachment-line boundary layer is computed by direct numerical simulation of the unsteady, incompressible Navier–Stokes equations. Disturbances are introduced into the boundary layer by harmonic sources that involve unsteady suction and blowing through the wall. Various harmonic-source generators are implemented on or near the attachment line, and the disturbance evolutions are compared. Previous two-dimensional simulation results and nonparallel theory are compared with the present results. The three-dimensional simulation results for disturbances with quasi-two-dimensional features indicate growth rates of only a few percent larger than pure two-dimensional results; however, the results are close enough to enable the use of the more computationally efficient, two-dimensional approach. However, true three-dimensional disturbances are more likely in practice and are more stable than two-dimensional disturbances. Disturbances generated off (but near) the attachment line spread both away from and toward the attachment line as they evolve. The evolution pattern is comparable to wave packets in flat-plate boundary-layer flows. Suction stabilizes the quasi-two-dimensional attachment-line instabilities, and blowing destabilizes these instabilities; these results qualitatively agree with the theory. Furthermore, suction stabilizes the disturbances that develop off the attachment line. Clearly, disturbances that are generated near the attachment line can supply energy to attachment-line instabilities, but suction can be used to stabilize these instabilities.

Enhanced Analytic Approach for Describing pH Triggered Fast Drug Release Systems

2021 ◽  
Vol 18 ◽  
Author(s):  
Aykut Elmas ◽  
Guliz Akyuz ◽  
Ayhan Bergal ◽  
Muberra Andac ◽  
Omer Andac
Keyword(s):  
Drug Release ◽  
Ph Dependence ◽  
Slope Angle ◽  
Ph Sensitive ◽  
Analytic Model ◽  
Two Dimensional ◽  
Analytic Equation ◽  
One Dimensional ◽  
Ph Dependent ◽  
Fast Release

Background: pH sensitive dendrimers attached to nanocarriers, as one of the drug release systems, has become quite popular due to their ease of manufacture in experimental conditions and ability to generate fast drug release in the targeted area. This kind of fast release behavior cannot be represented properly most of the existing kinetic mathematical models. Besides, these models have either no pH dependence or pH dependence added separately. So, they have remained one dimensional. Objective: The aim of this study was to establish the proper analytic equation to describe the fast release of drugs from pH sensitive nanocarrier systems. Then, to combine it with the pH dependent equation for establishing a two-dimensional model for whole system. Methods: We used four common kinetic models for comparison and we fitted them to the release data. Finding that, only Higuchi and Korsmeyer-Peppas models show acceptable fit results. None of these models have pH dependence. To get a better description for pH triggered fast release, we observed the behavior of the slope angle of the release curve. Then we puroposed a new analytic equation by using relation between the slope angle and time. Result: To add a pH dependent equation, we assumed the drug release is “on” or “off” above/below specific pH value and we modified a step function to get a desired behavior. Conclusion: Our new analytic model shows good fitting, not only one-dimensional time dependent release, but also two-dimensional pH dependent release, that provides a useful analytic model to represent release profiles of pH sensitive fast drug release systems.

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