Outlet Valve Research Articles

Structural Analysis and Optimization of Urban Gas Pressure Regulator Based on Thermo-Hydro-Mechanical Coupling

As a core component in the gas transmission process, the internal wall surface of a gas pressure regulator is prone to failure due to long-term exposure to a high-pressure gas environment, resulting in poor reliability of the regulator. Thus, a thermo-hydro-mechanical coupling model for the FL gas pressure regulator is established in this paper, and the thermo-hydro-mechanical coupling results are verified by engineering data. The effect of valve opening on the parameters (temperature, deformation, and stress) of the gas pressure regulator is studied in detail through simulation. The results show that the stress is greater at the sleeve, valve bore, and outlet valve seat wall under the opening of 20% of the regulator. Finally, the response surface method is used to optimize the regulator to obtain a good fit and high predictive ability of the response surface equation. The optimal parameters for the gas pressure regulator are as follows: the wall thickness of the sleeve is 7.25 mm, the diameter of the valve bore is 25 mm, and the wall thickness of the outlet seat is 31.05 mm. The maximum equivalent stress with this combination of parameters is 135.62 MPa.

Review of Compressed Air Receiver Tanks for Improved Energy Efficiency of Various Pneumatic Systems

This review examines compressed air receiver tanks (CARTs) for the improved energy efficiency of various pneumatic systems such as compressed air systems (CAS), compressed air energy storage systems (CAESs), pneumatic propulsion systems (PPSs), pneumatic drive systems (PDSs), pneumatic servo drives (PSDs), pneumatic brake systems (PBSs), and compressed air vehicles (CAVs). The basic formulas and energy efficiency indicators used in a CART calculation and selection are included. New scientific research by the authors on measurements based on tank methods, numerical solutions in the process of charging and discharging, the valve-to-tank-to-valve system and pneumatic propulsion system was presented. The numerical model of the valve-tank-valve system takes into account CART polytropic charging and discharging processes, the mass flow balance equation, and the sound (choked) and subsonic mass flow rate in the inlet and outlet valves. Future research directions to improve the energy efficiency of a CART charging and discharge are highlighted. The effective density of energy storage in CART was compared to that of other renewable energy sources and other fuels. Economic and environmental issues were also considered by adopting various energy performance indicators. The discussion also focused on the design concept and computational model of the hybrid tricycle bike (HTB) pneumatic propulsion system.

TS2VLGNN-based prediction of water temperature at the outlet valve of a valve cooling system

During the operation of a power grid system, devices such as converter valves generate much heat, which leads to a constant increase in the device’s operating temperature, thus significantly reducing the stability and safety of the system. The temperature of the valve cooling system is critical to the stability of the system. In this paper, according to the limitations of traditional multivariate time series prediction methods, such as harrowing feature extraction and poor prediction performance, we propose a model TS2VLGNN to predict the valve cooling system’s outlet water temperature. TS2VLGNN first extracts the features of system variables through the time series-representation learning method TS2Vec and then combines the advantages of LSTM and GNN in multivariable time series prediction. Meanwhile, the GNN module is improved to predict the water temperature at the outlet valve. During the comparative experiment, the model was compared with several models, and the experimental results verified that the TS2VLGNN model has higher prediction performance. Finally, ablation experiments demonstrated each component of the model’s effectiveness.

Flow Performance Analysis of Double-Chamber Gas–Liquid Transferring Device

Gas–liquid transportation is an efficient and economical transportation technology developed in recent years. It mainly uses some transportation equipment to simultaneously transport crude oil, associated natural gas, produced water, and so on for the purpose of reducing costs and energy consumption. In this paper, a double-chamber gas–liquid transferring device was selected as the research object. The VOF multiphase flow model of FLUENT software was used to simulate the gas–liquid two-phase flow performance under the design condition. The relationships between the two-phase flows, pressure, temperature, liquid level in the tank, outlet flow rate of the device, and time were calculated and analyzed. The results show that the operating cycle of the device can be divided into three processes, namely ‘suction-compression-discharge’, in which the cycle period formula is proposed as well. The pressures of gas and liquid in the device are basically the same, but the temperatures of the two phases are quite different in the compression process. In the compression process, the outlet valve is closed so that the outlet flow rate of the device is zero, and the gas compression process can be approximately treated as isothermal compression in engineering design. The comparison between the measured performance data in the oil field and the calculation results indicates that the calculation method in this paper is feasible for the performance prediction and optimization of the double-chamber gas–liquid transferring device.

TECHNICAL SOLUTION OF PROBLEMS ARISING ON THE SUCTION AND DISCHARGE VALVES OF THR DRILING PUMP

The purpose of the article is to extend the operational life of piston pumps by making beneficial modifications to the suction and discharge valves. The most common cause of mud pump failures is the wears on the valves so there is an urgent need to increase the durability of the inlet and outlet valves. This research will allow us to: - lengthen the functional life of the suction and discharge valves. - develop the mud pump's technical requirements. - enhance the drilling pump's economic effectiveness. Thus, it makes sense to do study on piston mud pump valves in order to improve the technical parameters by making some positive adjustments. A moved forward valve situates which essentially diminishes the affect stretch caused by the effect of a piston pump valve body contrary the valve situates. The valve situate comprises a by and large round and hollow body parcel portion parcel with a fixing surface which is slanted from the external surface of the round and hollow body parcel toward an insides throat of said round and hollow body parcel. The valve body comprises a for the most part disc-shaped parcel and a truncated funnel shaped parcel. An elastomer embed is gotten in a groove within the valve body. The cone shaped parcel of the valve comprises an inclined confront, counting a metal parcel and an elastomeric parcel shaped by the elastomeric embed. Within the valve situate of the present innovation, an annular weight alleviation groove within the round and hollow body parcel of the valve situate permits the inclined confront of the valve situate to flex subsequently calming a noteworthy sum of the affect stack between the restricting confront of the valve gathering. Keywords: suction valve, discharge valve, valve wears, valve seat, poppet valve, piston mud pumps.

Steady-state interconnected cycle modeling and experimental results of a lab-scale ORC

ORC is one of the mature technologies for power generation from low temperature heat sources. In this study, the aim is to develop an accurate ORC model which is validated using reliable steady-state data. For this purpose, tests are carried out at four different heat source temperatures ranging from 80 to 110 °C to obtain data in a repeatable manner. The proposed model considers pressure drop and heat transfer correlations to improve the accuracy of model predictions. Using the refrigerant pump mass flow rate, thermal oil pump volumetric flow rate, cooling water inlet temperature, cooling water volumetric flow rate, the throttle valve outlet set pressure, and refrigerant pump outlet pressure as input, the model predicts the pressure, temperature, and mass flow rate in the cycle. The results show that the steady-state ORC model is significantly accurate, with ±1% deviations in pressure and ±1 °C in temperature, and ±5% in mass flow rate, heat transfer rate and refrigerant pump power predictions. The novel iterative model presented in this study includes pipe losses and significantly improves the simulation accuracy of ORCs with long pipes.

IAQ in CCU units: an experimental and numerical investigation based on the outlet air height (case study: Namazi Hospital, Shiraz)

Indoor air quality (IAQ) is a significant concern that affects our health. Recent studies show how poor IAQ amplifies the effects of airborne viruses, which endanger the health of the population relative to the COVID-19. This study aims to find the relationship among IAQ, the location of the air outlet valve and the behavior of the IAQ indicators in the cardiac care unit (CCU) at Namazi Hospital, Shiraz, Iran. In this context, the condition of the air outlet valve can play an important part in preparing a better IAQ. To test the hypothesis, articles based on IAQ guidelines have been studied. Also, certain emissions (CO2, CO, PM2.5 and PM10) have been measured, and the relationship between IAQ, the location of the air outlet valve and the behavior of these emissions in the patient’s room at Namazi Hospital. This room has been analyzed using computational fluid dynamics for the prediction of the specification of incoming air flow particles. Also, a Eulerian–Lagrangian model was used. In constant, the turbulence model (realizable k – ԑ) and discrete particle model were employed. The results show that when the outlet valve is placed on the wall at 20 cm, it decreased particle deposition in the room, and as a result, IAQ will be improved and at the same time, the chances of transmitting infectious diseases will be reduced. It is also indicated that a higher amount of particle deposition fraction (ca. 0.71) obtains when the outlet valve is located on the top of the wall.

Influence of Valve-Seat Angles to Operation Values and Emissions of Medium-Speed Diesel Engines

Abstract For the development of gas exchange for large diesel engines, a compromise has to be found between efficient valve-flow and the time between overhauls. On the one hand, large effective flow areas, especially during valve-overlap, are demanded. On the other hand, there are limitations of cylinder bore regarding the maximum diameter of inlet and outlet valves and the minimum distance (dead space) between valves and piston, as well as wear-related smaller seat angles. For large medium-speed diesel engines, a valve-seat angle of β = 30° for inlet and outlet valves is a standard application. For engine-operation with clean fuels, a valve-seat lubrication (gasoil) or smaller seat angles (natural gas) need to be applied. With this presentation, the basic influence of different valve-seat angles on the operation values and emissions will be considered for the example of the single-cylinder research engine FM16/24. Using a self-developed testbed, experimental investigations into effective flow areas as a function of valve-lift at inlet and outlet valves have to be executed. With this input, different cycle calculations including T/C have to be carried out to determine deviances in specific fuel-oil consumption, exhaust-gas temperatures, NOx emissions and air/fuel ratio. The results will be discussed critically.

Model predictive control of stormwater basins coupled with real-time data assimilation enhances flood and pollution control under uncertainty

Smart stormwater systems equipped with real-time controls are transforming urban drainage management by enhancing the flood control and water treatment potential of previously static infrastructure. Real-time control of detention basins, for instance, has been shown to improve contaminant removal by increasing hydraulic retention times while also reducing downstream flood risk. However, to date, few studies have explored optimal real-time control strategies for achieving both water quality and flood control targets. This study advances a new model predictive control (MPC) algorithm for stormwater detention ponds that determines the outlet valve control schedule needed to maximize pollutant removal and minimize flooding using forecasts of the incoming pollutograph and hydrograph. Comparing MPC against three rule-based control strategies, MPC is found to be more effective at balancing between multiple competing control objectives such as preventing overflows, reducing peak discharges, and improving water quality. Moreover, when paired with an online data assimilation scheme based on Extended Kalman Filtering (EKF), MPC is found to be robust to uncertainty in both pollutograph forecasts and water quality measurements. By providing an integrated control strategy that optimizes both water quality and quantity goals while remaining robust to uncertainty in hydrologic and pollutant dynamics, this study paves the way for real-world smart stormwater systems that will achieve improved flood and nonpoint source pollution management.

Computational fluid dynamic analysis of corona virus patients breathing in an airplane

Effective ventilation systems are essential to control the transmission of airborne aerosol particles, such as the SARS-CoV-2 virus in aircraft cabins, which is a significant concern for people commuting by airplane. Validated computational fluid dynamic models are frequently and effectively used to investigate air distribution and pollutant transport. In this study, the effectiveness of different ventilation systems with varying outlet vent locations were computationally compared to determine the best ventilation system for minimizing the risk of airborne transmission. The cabin air conditioning system was optimized to determine how design variables (air inlet temperature, outlet valve width and location, and mass flow rate) affect output parameters, including particle residence time, age of air, and thermal comfort conditions. Inlet mass flow rate was observed to be an influential variable impacting all output parameters, especially on age of air, where it was the most influential. In contrast, the least effective variable was width of the outlet valve, which only affected the particle residence time. Also, Predicted Mean Vote and Predicted Percentage Dissatisfied indices were the most affected by air inlet temperature, which had an inverse relation, while the outlet valve location had the greatest effect on particle residence time.

Co-Simulation Modeling and Multi-Objective Optimization of Dynamic Characteristics of Flow Balancing Valve

The poor dynamic characteristics of the flow balance valve used in a ship’s HVAC system are the main reasons for the hydraulic imbalance and high energy consumption of the system. A new adjustable dynamic flow balance valve structure is designed, which is composed of a self-operated pressure regulator and an electric V-shaped ball valve in series. When the V-shaped ball valve is fully opened at the 20 t/h flow level, the dynamic characteristics of the flow balance valve cannot meet the requirements. A new co-simulation method that combines MATLAB/Simulink and the UDF dynamic grid is proposed to study the dynamic characteristics of a flow balance valve with a 20 t/h flow rate under different pressure drop step signal interference. When the calculation of each micro-element time converges, the valve core motion parameters, the pressure boundary conditions, the valve core axial medium force, and the valve outlet flow are interactively transmitted in the two simulation environments. The discrepancy between the co-simulation and test results is less than 5%, which verifies the accuracy of the co-simulation model. Aiming at the most severe dynamic characteristic working condition where the pressure drop is stepped from 30 to 300 kPa, the influence of different structural parameters on the dynamic characteristics of the balance valve is analyzed. A new surrogate model combining RSM and RBF with the co-simulation method improves the optimization efficiency and fitting accuracy. To improve the convergence of the traditional NSGA-II algorithm, key structural parameters are optimized by combining the NSGA-II algorithm and SDR. The test results show that the dynamic characteristics of the optimized valve are improved, the discrepancy between the stabilized flow rate and 20 t/h does not exceed 4.5%, and the flow is relatively constant. Therefore, the proposed co-simulation and optimization method can be applied to the dynamic characteristic prediction of self-operated valves, such as dynamic flow balance valves, to provide guidance for developing high-precision self-operated valves.

Dynamic Simulator for Three-Phase Gravity Separators in Oil Production Facilities.

In this study, a dynamic simulator for three-phase gravity separators in oil production facilities is proposed. The mass conservation equation is established to calculate the pressure, water level, and oil level in the separator and the mass balance equation of the dispersed phase to calculate the oil-water separation efficiency. The proportional integral controllers are applied to control the water level, oil level, and pressure in the separator by setting the opening of the three outlet valves of oil, gas, and water. The model is verified using field data by means of the given valve opening and given proportional integral controller parameters, respectively. Subsequently, the verified simulator is applied to study the dynamic behavior of the separator filling process and the effect of pressure, oil level, and water level setpoint changes on the separator operating status. A detailed analysis of the changes in the liquid level, pressure, and opening of three outlet valves is presented. Then, the effects of operating conditions such as the inlet flow, water setpoint, and weir height on the separation efficiency are discussed. This simulator can be applied for the design of oil, gas, and water three-phase separation processes. In addition, through this simulator, the parameters that are difficult to be measured by instruments during the operation of the separator can be calculated, providing technical support for the construction of the digital twin of the separator.

Modeling and Control of a Multiple-Heat-Exchanger Thermal Management System for Conventional and Hybrid Electric Vehicles

The powertrain in combustion engine and electric vehicles requires a thermal management system to regulate the operating temperature of the under-hood components. The introduction of computer-controlled cooling system actuators (e.g., variable speed fans, pump, and valves) enables power savings over drive cycles. The radiator is typically sized for maximum heat rejection per environmental and vehicle thermal loading conditions. This paper explores the use of multiple radiators to adapt the cooling system operations to driving demands. A nonlinear multiple-input (i.e., fan array speed, pump, and outlet valve positions) thermal model is presented to predict system behavior. A stateflow controller has been designed and implemented to maintain the component temperature within a desired range (~80 °C). A series of experimental tests have been conducted to compare the proposed architecture’s performance against a single radiator design. A standard driving cycle featuring low (20 kW) and high (40 kW) heat loads was implemented in the laboratory for a vehicle starting from rest. The coolant temperature tracking, fan speeds, and fan power draw were studied over the representative operating cycle. The test results show a much faster warmup time (~10 min) and temperature tracking for the twin radiator experimental test as compared to the single radiator (~13 min). The net fan energy consumption was reduced by 4.6% with the twin radiator as opposed to the single-radiator configuration. Considering that engines usually operate at idle to medium loads, these findings can improve the powertrain’s overall performance.

Effect of diesel engine modification operated with karanja biodiesel and its blends

• Increased biodiesel blends, such as B30 and B40, result in decreased engine performance (BTE) and higher smoke, HC and NOx emissions. • The B20 blend is an appealing alternative because it enhances engine performance while lowering emissions. • The country’s economy benefits from the substitution of fossil fuels for indigenous renewable and alternative fuels. • This alternative is more realistic because there are abundant resources of non-edible oil seeds for biodiesel preparation and biodiesel production costs are becoming more affordable. Growing attention in studying renewable and alternate fuels for internal combustion (IC) engines has been increased by concerns about improving engine performance while reducing emissions to satisfy EURO standards and to fulfil increasing energy demands for a growing population. Biodiesels are a possible replacement to diesel fuel since, they are renewable and have qualities similar to fossil diesel. For diesel engines, biodiesel generated from Karanja oil is a better diesel substitute. The use of alternative fuels in a CI (Compression ignition) engine reduces performance while also increasing hydrocarbon (HC) and carbon monoxide (CO) pollutants. However, making the engine entirely adiabatic by combining biodiesel with diesel and applying thermal barrier coatings (TBC) to the piston, cylinder wall, and inlet and outlet valves will improve overall engine performance. In light of this, TBC diesel engine components coated with partly stabilized zirconia (PSZ) and aluminium oxide (Al 2 O 3 ) ceramics were tested in a diesel engine using Karanja oil methyl ester (KOME) and its mixtures. Both diesel and KOME and its blends had their brake thermal efficiency (BTE) emissions measured before and after coating, and the obtained results were matched. Engine performance is nearly comparable with acceptable emission requirements while using B20 powered biodiesel and a PSZ coated engine. Among the biodiesels tested, the maximum BTE was recorded with diesel which was 2.79%, 5.89%, 7.75%, 9.64% and 14.03% greater than B10, B20, B30, B40 and B100 fuel blends. From various fuels tested, the minimum smoke emissions were recorded with diesel which was 6.06%, 12.9%, 20.68%, 29.62% and 39.88% lower than B10, B20, B30, B40 and B100 fuel blends.

Experimental investigation and performance improvement of a new combined T-junctions gas-liquid separator

The objective of this paper is to study the gas-liquid separation performance and its improvement of a new combined T-junctions separator by experiments. This separator is constructed of large-diameter T-junctions (50 mm and 60 mm), symmetrically arranged in annulus. The test conditions include complete separation and incomplete separation. The gas-liquid flow characteristics of the combined T-junctions were visually observed and analysed during the separation process. The separation characteristic was quantified (F) and the effects of liquid level, inlet superficial velocities (JG1 and JL1) and outlet valve opening degree on the separation efficiency (F) were confirmed. The results show the connections between the parameters and separation efficiency. Based on the above, a self-regulating level controller is designed, which can significantly extend the range of inlet gas velocity (JG1) to 4.5 times and inlet liquid velocity (JL1) to two times for complete separation, but the level controller fails when the inlet gas-liquid velocities are too high (JG1 > 10.27 m/s, JL1 > 0.52 m/s). [Received: December 14, 2021; Accepted: August 7, 2022]

AN EXPERIMENTAL INVESTIGATION TO PREDICT OPTIMUM CHARGE OF A HEAT PUMP SYSTEM

Working principles of heat pumps is an important matter from a thermodynamic point of view that has been researched from various aspects. In this study, undercharged, optimum charged, and overcharged conditions of a heat pump were investigated using R134a refrigerant. Variations in temperature, pressure, and the coefficient of performance have been evaluated and it was aimed to find out the optimum charge condition considering different parameters. According to the experimentally obtained findings, the coefficient of performance was increased by more than three times when the refrigerant amount increased from 2000 g to ~ 7300 g. The general outcomes of the present study indicated that optimum refrigerant charge amount can notably affect the performance of heat pump apparatus. It was shown that the P-h diagram of all heat pump systems depends on the working conditions and the refrigerant charge is a very important criterion that can make significant changes in the P-h diagram. It was found that, by increasing refrigerant charge, after the downtrend starts in the compressor inlet temperature, 20% refrigerant can be added to achieve the maximum COP value. Additionally, the critical point in expansion valve outlet temperature was used to find the optimum charge. It was revealed that if 140% refrigerant is added to the given refrigerant at critical point, the optimum COP value can be achieved.

Constructions of the experimental-estimation model for releasing combustion products at thermal pulse processing

The object of this study are ways to ensure the speed and repeatability of the valve for the release of combustion products from the thermal-pulse unit, which are the most important parameters that enable the precision of the finishing treatment with detonating gas mixtures. The study is aimed at analyzing the process of releasing combustion products in the valve of the proposed design; identification of factors that affect the speed of its opening; establishing the nature of the change in gas dynamic parameters in the combustion chamber. Experimental studies were carried out on a specialized bench simulating the operation of a valve with pressure measurement in gas cavities and controlling the movement of a movable glass of the valve with an incremental encoder. Information on the position of the movable cup is obtained in real time with a decisive ability of 3 microns. The experimental study showed that an increase in the response rate of the valve of the design under consideration to the values required for precision thermal pulse treatment (0.01 s) is possible subject to the use of compressed air. To study the flow processes of high-temperature gases during the operation of the controlled outlet valve, partially immersed in water, a numerical model has been built. A feature of the model is to take into account the real values of the friction force acting on the moving part of the valve, due to the introduction of resistance force acting on the movable glass. The magnitude of this force under the specified initial conditions is assigned from the condition of ensuring the coincidence between the estimated opening time of the valve and its average value obtained from full-scale experiments. For the range of design conditions, based on the lower limit of the working pressure of the combustion products, the water level is determined in the chamber of the thermal pulse equipment, on which the valve must be partially immersed for safe operation

Review of Flow-Matching Technology for Hydraulic Systems

The flow-matching problem of hydraulic systems is an important factor affecting the working performance and energy saving of hydraulic systems. According to the different flow-matching mechanisms, the flow-matching technology of hydraulic systems can be divided into three categories: positive flow-control technology, negative flow-control technology, and load-sensitive control technology. In this paper, the working mechanism of flow-matching technology and the cause of energy loss are analyzed, and the research results of flow matching are introduced from two aspects of energy saving and consumption reduction and system performance improvement. In the direction of energy saving and consumption reduction, the purposes of energy saving and consumption reduction are achieved by means of multi-way valve commutation, independent inlet and outlet control, parallel replacement of shuttle valve by a cylinder piston rod controlled by pilot pressure, change of hydraulic resistance of a pressure compensating valve, improvement of the power regulation range of a hydraulic pump, and potential energy recovery. In the direction of system performance, by means of flow-forecasting system pressure change, applying flow unsaturation real-time control idea, and combining electronic control technology with load-sensitive technology, the pressure drop during transmission process and the transmission signal lag are reduced, the speed regulation interval is enlarged, fine-tuning characteristics are improved, and the response speed is increased. The research results indicate that improving the structure and the control strategy of hydraulic systems and improving the flow-matching degree of a system to achieve global matching will be a future development trend.

Hydraulic Performance of Howell–Bunger and Butterfly Valves Used for Bottom Outlet in Large Dams under Flood Hazards

Floods control equipment in large dams is one of the most important requirements in hydraulic structures. Howell–Bunger valves and butterfly valves are two of these types of flow controls that are commonly used in bottom outlet dams. The optimal longitudinal distance (L) between the two Howell–Bunger and butterfly valves is such that the turbulence of the outlet flow from the butterfly valve should be dissipated before entering the outlet valve. Subsequently, the flow passing through the butterfly valves must have a fully developed flow state before reaching the Howell–Bunger valve. Therefore, the purpose of this study was to evaluate the optimal longitudinal distance between the Howell–Bunger and butterfly valves. For this purpose, different longitudinal distances were investigated using the Flow-3D numerical model. The ideal longitudinal distance obtained from the numerical model in the physical model was considered and tested. Based on the numerical study, the parameters of flow patterns, velocity profiles and vectors, turbulence kinetic energy, and formation of flow vorticity were investigated as criteria to determine the appropriate longitudinal distance. In addition, the most appropriate distance between the butterfly valve and the Howell–Bunger valve was determined, and the physical model was evaluated based on the optimal distance extracted from the numerical simulation. A comparison of the results from the numerical and the laboratory models showed that the minimum distance required in Howell–Bunger valves and butterfly valves should be equal to four times the diameter of the pipe (L=4D) so as not to adversely affect the performance of the bottom outlet system.

Design, modeling, and simulation of dual-source redundant braking system

Based on the existing theory of EHB braking system, a new dual-source redundant braking system (DSRB) is proposed in this paper. The proposed DSRB is improved on the classic ESP system structure with two sets of motor hydraulic pumps, four throttle valves and two balance valves used to replace the failed oil inlet and outlet valves added in it. Then, the requirements of redundancy, reliability of intelligent vehicle braking system can be met by the system. The wheel cylinder pressure of DSRB system is accurately regulated by PID control algorithm. Finally, the co-simulation based on AMEsim/Simulink were implemented to verify the accuracy and reliability of the braking efficiency of the DSRB. Results show that the designed DSRB has fault tolerance even in the case of partial failure, that is, inlet and outlet valve failure and complete failure, that is, inlet and outlet valve and hydraulic motor failure at the same time. And good braking efficiency, boosting speed and pressure regulation accuracy are still available.