Study on the Structural Configurations and Pressure Regulation Characteristics of the Automatic Pressure Regulating Valve in the Electronically Controlled Pneumatic Brake System of Commercial Vehicles

Based on the classification of automated driving by the SAE (Society of Automotive Engineers) and the working principle of the ECPBS (Electronically Controlled Pneumatic Brake system), the requirements and the control modes of the APRV (Automatic Pressure Regulating Valve) were concluded. Four structural configurations for APRV were proposed to meet the requirements of the ECPBS. To study the pressure regulating characteristics of the APRV of different structure configurations, a simulation model was established, and a test bench was built. Through experiments, the correctness and the reliability of the simulation model were verified. The pressure regulation characteristics of the APRV of different structure configurations under different control conditions were revealed, and the suitable levels in the SAE automated driving classifications for automatic pressure regulators of different structure configurations were determined; thus, the theoretical underpinning to improve driving safety and develop automated driving was provided.

Analysis of Pressure Response Characteristics and Influencing Factors of the Automatic Pressure Regulating Valve in Electronic-Controlled Pneumatic Braking System of Commercial Vehicle

Automatic pressure regulating valve is the core pressure regulating element in electronic-controlled pneumatic braking system of commercial vehicle, its pressure response characteristics directly affect the real-time and rapid pressure regulation. In this paper, the influence of structural parameters of high-speed solenoid valve on its pressure response characteristics is studied. By analyzing the working principle and structure of high-speed solenoid valve, the mathematical model was established by AMESim. Through the combination of simulation and experiment the correctness of the model is verified. Finally, according to the influence law of key structural parameters in high-speed solenoid valve on the pressure response characteristics of automatic pressure regulating valve, a set of optimized parameters are obtained to realize the improvement and optimization of the pressure response characteristics of the automatic pressure regulating valve.

Performance Analysis of Smoke Control Systems for Elevators based on Pressurization Method

The pressurization of emergency or evacuation elevator shafts or duct systems during installation is used for smoke control. In this study, the performance of smoke control systems applied to emergency and evacuation elevators were compared and analyzed using the airflow network analysis program CONTAM 3.2. Under the stack effect condition (temperature difference of 30 ℃), the differential pressure formed in the vestibule was analyzed by adjusting the air volume by changing the value of the loss coefficient factor of the automatic pressure smoke damper. In the case of the duct pressurization method, the air flow in the lower floor was introduced to the elevator shaft owing to the duct pressure and the airflow in the upper floors was from the elevator shaft out to the elevator lobby. In the case of the elevator shaft pressurization method, the pressurized air passing through vestibule from the elevator shaft created a differential pressure at the fire door of vestibule. To maintain the differential pressure in the lower floor, relatively more relief dampers should be installed in the upper floors as compared to those in the duct pressurization method.

Study on Pressure Change Rate of the Automatic Pressure Regulating Valve in the Electronic-Controlled Pneumatic Braking System of Commercial Vehicle

In contrast to the traditional pneumatic braking system, the electronic-controlled pneumatic braking system of commercial vehicles is a new system and can remedy the defects of the conventional braking system, such as long response time and low control accuracy. Additionally, it can adapt to the needs and development of autonomous driving. As the key pressure regulating component in electronic-controlled pneumatic braking system of commercial vehicles, automatic pressure regulating valves can quickly and accurately control the braking pressure in real time through an electronic control method. By aiming at improving driving comfort on the premise of ensuring braking security, this paper took the automatic pressure regulating valve as the research object and studied the pressure change rate during the braking process. First, the characteristics of the automatic pressure regulating valve and the concept of the pressure change rate were elaborated. Then, with the volume change of automatic pressure regulating valve in consideration, the mathematical model based on gas dynamics and the association model between pressure change rate and vehicle dynamic model was established in MATLAB/Simulink and analyzed. Next, through the experimental test of a sample product, the mathematical models have been verified. Finally, the key structure parameters affecting the pressure change rate of the automatic pressure regulating valve and the influence law have been identified; therefore, appropriate design advice and theoretical support have been provided to improve driving comfort.

IMPROVING THE QUALITY OF RAPEED OIL FOR USE IN A DIESEL ENGINE

This article presents experimental studies on changing such chemical properties of vegetable (rapeseed) oil, such as viscosity, for its use as a fuel in diesel engines. With the help of hydrothermal technology, samples of vegetable oil were obtained and laboratory studies were carried out on a viscometer, which showed a decrease in viscosity up to 16%. Oil samples were obtained at different pressures up to 90 atm. and temperatures up to 130 C. All samples were passed through a liquid activator installed at the outlet of the reactor, which, due to spargers located in the path of the flow, provided the appearance of a gaseous and liquid mixture with an increased ability to mix and conduct chemical reactions. The reactor was a metal flask with a wall thickness of 10 mm, a volume of 6 liters, with installed temperature and pressure sensors, and a heating element for heating oil. The pressure was provided by a gear pump driven by a 3 kW electric motor. For the safety of testing, an automatic pressure and temperature regulator in the reactor, installed in the control panel, was developed. In order to compare with pure cold-pressed rapeseed oil, comparative tests were carried out on bench equipment of the laboratory, which showed the effectiveness of this technology and obtaining the characteristics of engine operation on rapeseed oil as close as possible to diesel fuel. During the research, quantitative indicators of the ingress of rapeseed oil into the engine crankcase were also determined. When using cold-pressed rapeseed oil, this figure after eight-hour tests at idle at different speeds was 3.21 liters. After the processing of rapeseed oil in the reactor and repeated tests, the oil in the engine crankcase was measured, where it was 1.92 liters, which was 60% of the previous experience

Design Features of the User Interface of the Pipeline Pressure Control Monitoring System

For control and regulation of hydraulic systems, especially, oil pumping stations, automatic pressure control systems (APCS) are used. Using it, the monitoring, controlling, and adjusting the operation of technological equipment, optimization of modes, and other tasks that require direct human participation become possible. The operator (or dispatcher) interacts with the system via a human-machine interface. The monitoring system includes programs for collecting, processing, displaying, and archiving information about the object of observation and control. Well-suited and being put to the right user interface design promotes not only the effective interaction of the operator with the system in normal conditions but also prevents errors and helps to find a solution in a dangerous or emergency swiftly. This paper presents a software package designed for real-time monitoring and regulation of pipeline operation. A system simulation model is provided for the teaching and training of site personnel.

Modeling and Design of the Automatic Pressure Regulating Valve in the Foam Firefighting System

This paper presents a novel design of the automatic pressure balancing valve, used in the in-line balanced pressure (ILBP) proportioner for the foam firefighting system, at a required percentage of solution. Featured in a four-chamber configuration with a double-acting diaphragm actuator, it can automatically maintain the foam concentrate pressure with the pressure in the supply water pipeline, within a precision level of 0.02 MPa (or 1.3%), under the design operating condition. The static characteristics at the equilibrium state have been discussed in terms of poppet displacement with reference to the geometrical dimensions and operating pressures of the valve. The dynamic response of the valve during the startup has been examined through building the mathematical model of the forces on the valve and solving it numerically using MATLAB. The results show that the response time of the valve is always less than 0.01 s, which fully satisfies the stability and hysteresis requirement. The prototype has been tested in the laboratory, which agrees well with the numerical results. It was then successfully put into production, forming the first series of ILBP foam pump firefighting system in China.