Study of Flow Pressure Characteristics of Improved Rotary Valve

This work was supported in part by The National Natural Science Fund of China, Scientific research fund of Nanjing Institute of Technology, Open fund project of Anhui University of Technology, Practical innovation project of graduate students in Jiangsu Province. Support Fund Nos. 51505211, 11302097, CKJB201901, HVC202004, SJCX20_0700.

Organization of Six-Cylinder Tractor Diesel Working Process

The purpose of the work is to consider the organization of the working process of six-cylinder diesel engines with a power of 116 and 156 kW and exhaust gas recirculation. The following systems and components were used in the experimental configurations of the engine: Common Rail BOSСH accumulator fuel injection system with an injection pressure of 140 MPa, equipped with electro-hydraulic injectors with seven-hole nozzle and a 500 mm3 hydraulic flow; direct fuel injection system with MOTORPAL fuel pump with a maximum injection pressure of 100 MPa, equipped with MOTORPAL and AZPI five-hole nozzle injectors; two combustion chambers with volumes of 55 and 56 cm3 and bowl diameters of 55.0 and 67.5 mm, respectively; cylinder heads providing a 3.0–4.0 swirl ratio for Common Rail system, 3.5–4.5 for mechanical injection system. The recirculation rate was set by gas throttling before the turbine using a rotary valve of an original design. The tests have been conducted at characteristic points of the NRSC cycle: minimum idle speed 800 rpm, maximum torque speed 1600 rpm, rated power speed 2100 rpm. It has been established that it is possible to achieve the standards of emissions of harmful substances: on the 116 kW diesel engine using of direct-action fuel equipment and a semi-open combustion chamber; on the 156 kW diesel using Common Rail fuel supply system of the Low Cost type and an open combustion chamber.

Design of Low-Cost Endoscope Based On Novel Wire-Driven Rotary Valve and Water-Jet Mechanism

To improve the prevalence of screening for gastric cancer in low-income areas, a low-cost endoscope based on a novel wire-driven rotary valve and water-jet mechanism is proposed. The primary component of this endoscope is a rotary valve whose core is driven by a step motor through a flexible wire, which controls the direction of the water jet. This enables it to reach any point in the workspace by controlling the valve core angle and water jet intensity. The envelope surface of the endoscope tip trajectory is likely a hemisphere. The horizontal diameter of the working space projection is approximately 350 mm, which is sufficient to observe most parts of the greater curvature of the stomach. The image-acquisition performance of the designed endoscope was satisfactory in a phantom experiment. The introduction of the novel rotary valve greatly simplifies the structure and reduces the cost of the proposed endoscope. With low cost and high portability, this endoscope provides a good alternative for early gastric cancer screening in low- and middle-income areas.

Making design decisions under uncertainties: probabilistic reasoning and robust product design

Making design decisions is characterized by a high degree of uncertainty, especially in the early phase of the product development process, when little information is known, while the decisions made have an impact on the entire product life cycle. Therefore, the goal of complexity management is to reduce uncertainty in order to minimize or avoid the need for design changes in a late phase of product development or in the use phase. With our approach we model the uncertainties with probabilistic reasoning in a Bayesian decision network explicitly, as the uncertainties are directly attached to parts of the design artifact′s model. By modeling the incomplete information expressed by unobserved variables in the Bayesian network in terms of probabilities, as well as the variation of product properties or parameters, a conclusion about the robustness of the product can be made. The application example of a rotary valve from engineering design shows that the decision network can support the engineer in decision-making under uncertainty. Furthermore, a contribution to knowledge formalization in the development project is made.

Organization of the Six-Cylinder Tractor Diesel Working Process

The purpose of the work is the organization of the six-cylinder diesel engines (with a power of 116 and 156 kW) working process with exhaust gas recirculation. The following systems and components were used in the experimental configuration of the engine: Common Rail BOSСH accumulator fuel injection system with an injection pressure of 140 MPa equipped with electro-hydraulic injectors with 7-hole nozzle and a 500 mm3 hydraulic flow; direct fuel injection system with MOTORPAL fuel pump with a maximum injection pressure of 100 MPa, equipped with MOTORPAL and AZPI five-hole nozzle injectors; two combustion chambers with volumes of 55 and 56 cm3 and bowl diameters of 55 and 67.5 mm; cylinder heads providing a 3-4 swirl ratio for Common Rail system, 3.5-4.5 for mechanical injection system; recirculation rate was set by gas throttling before the turbine using original design rotary valve. The tests were conducted at characteristic points of the NRSC cycle: minimum idle speed 800 rpm, maximum torque speed 1600 rpm, rated power speed 2100 rpm. It is established: achievement of emission standards for the 116 kW diesel engine is possible with the use of direct-acting fuel equipment and a semi-open combustion chamber; on the 156 kW diesel - using the Low Cost type common Rail fuel supply system and an open combustion chamber.

Load torque analysis and compensation device design for low power drilling fluid continuous wave generator

As an advanced downhole instrument in drilling engineering, drilling fluid continuous wave generator (DFCWG) has great application prospects. The large load torque is one of the key problems that hinder the development of DFCWG. In this paper, based on the design theory of rotary valve and finite element method, the structure of rotary valve is designed and the load torque characteristics is analyzed and points out that the load torque has strong alternating characteristics. It is pointed out that the load torque has the characteristics of strong alternating. According to the characteristics of the load torque, the "fluid-magnetic" collaborative compensation method is proposed. The load compensation turbine and magnetic compensation device are used to compensate the DC and AC components of the load torque respectively, and the load compensation device is designed. The rationality of the design of the load compensation device is verified by simulation. Finally, the comprehensive compensation effect is analyzed by the finite element method. According to the analysis results, the "fluid-magnetic" collaborative compensation method can effectively reduce the load torque. The research results can provide technical support for DFCWG design.

Rotation Speed Control of the Rotary Valve in MWD Tools Based on Speed Feedforward Compensation

The rotary valve speed control, seriously affected by the nonlinear characteristic of rotary valve load torque, affects the generation of drilling fluid pressure phase shift keying (PSK) signal and its quality. The calculation model feedforward of the load torque acts on the speed control system and enables the motor voltage to change according to the law of calculation model, and the linearization correction of the speed system is performed. Additionally, the flow measurement is introduced into the calculation model of the load torque to track the load torque change with the flow, suppressing the influence of large changes in flow rate on open-loop control of rotary valve speed. The closed-loop proportional-integral-derivative (PID) control is formed by negative feedback of speed, and the PID parameter value rule is established based on the rapid decay control of transient component in the rotary valve speed step response, which speeds up the tracking of the rotary valve speed following the control voltage pulse and reduces the distortion of the drilling fluid pressure PSK signal, increasing the frequency of the drilling fluid pressure carrier and improving the transmission rate of downhole information. Simulink simulation indicates that the closed-loop PID control of rotary valve speed can track the change of control voltage pulse quickly and strongly suppress the interference influences from flow measurement error and load torque calculation model deviation.

Experimental Investigation of a Radial Wave Engine Utilizing a Rotary Valved Pressure Gain Combustor

In this paper a deflagrative pressure gain combustor employing rotary valves is introduced that can reduce combustor length by allowing the combustion process to take place in the radial direction rather than in the axial direction with sufficient resident time. The engine is described in some detail with respect to geometry, components, and potential benefits. A demonstrator rig was designed, built, and tested for concept verification. A series of initial tests sweeping equivalence ratio from 0.4 to 0.8 using ethylene as fuel and mass flows from 75 g/s to 150 g/s is presented. The turbine rotor was driven to above 200 RPM with just four of the combustor passages operating. The initial results indicate the feasibility of the rotary valve radial engine concept and identified key challenges associated with the concept. Further studies are needed address existing challenges and to promote the engine development.