CN115370761B

CN115370761B - Monitoring device for fuel control valve

Info

Publication number: CN115370761B
Application number: CN202211010474.5A
Authority: CN
Inventors: 李欣; 周进
Original assignee: Sihong Zhigong Precision Machinery Co ltd
Current assignee: Sihong Zhigong Precision Machinery Co ltd
Priority date: 2022-08-23
Filing date: 2022-08-23
Publication date: 2023-08-22
Anticipated expiration: 2042-08-23
Also published as: CN115370761A

Abstract

The application relates to the technical field of fuel pressure valve detection, in particular to a monitoring device for a fuel control valve; the application comprises a monitoring component and a pressure stabilizing component which are arranged on a fuel valve, wherein the inside of the fuel valve is divided into an air cavity and a liquid cavity which are mutually isolated from each other up and down through a movable part, the movable part comprises a valve seat and a diaphragm, the edge of the valve seat is connected with the inner side wall of the fuel valve in a sealing way through the diaphragm, the upper end of the valve seat is connected with the inner wall of the top end of the air cavity through a spring, the lower end of the valve seat is provided with a valve ball matched with the pipe orifice of the input end of an oil return pipe, the bottom of the fuel valve is symmetrically provided with a group of oil inlet pipes, the top of the fuel valve is symmetrically provided with a group of air guide pipes, and the top of the fuel valve is provided with an electric joint; the application can realize the monitoring of the vibration frequency and amplitude of the valve seat in the fuel valve, whether cavitation phenomenon exists in the oil return pipe, whether the surface of the diaphragm is perfect and has no cracks and other projects.

Description

Monitoring device for fuel control valve

Technical Field

The application relates to the technical field of fuel pressure valve detection, in particular to a monitoring device for a fuel control valve.

Background

The fuel pressure valve, called fuel pressure regulating valve, is regulated by fuel pressure, and is connected with air inlet manifold by means of vacuum tube, and is controlled by vacuum negative pressure to make the air inlet manifold negative pressure be raised, and if the engine is idle, its rotating speed is low, throttle valve opening degree is small, fuel consumption is low, and the diaphragm of fuel pressure regulator can be driven to make fuel pressure relief opening be raised, and can make fuel pressure be reduced, fuel oil return be raised, and if it is high-speed, its rotating speed is high, throttle valve opening degree is large, and air inlet manifold negative pressure is reduced, and the regulating diaphragm of fuel pressure regulator is close to closed state, fuel pressure is raised so as to provide the high-speed engine with more fuel requirements for fuel.

The performance parameters (including but not limited to, the vibration frequency and amplitude of the valve seat inside the fuel valve, whether cavitation exists inside the oil return pipe of the fuel valve, whether the membrane inside the fuel valve is perfectly sealed, etc.) of the fuel valve during operation are stable and precisely have great influence on the performance of the automobile power system, so that it is highly desirable to design a device capable of monitoring the vibration frequency and amplitude of the valve seat inside the fuel valve, whether cavitation exists inside the oil return pipe, whether the surface of the membrane is perfectly free of cracks, etc.

Disclosure of Invention

The present application aims to solve the drawbacks of the prior art and to solve the problems set forth in the background art.

In order to achieve the above purpose, the present application adopts the following technical scheme: a monitoring device for a fuel control valve comprises a monitoring component and a pressure stabilizing component which are arranged on the fuel valve;

the inside of the fuel valve is divided into an upper air cavity and a lower air cavity which are mutually isolated through a movable part, the movable part comprises a valve seat and a diaphragm, the edge of the valve seat is connected with the inner side wall of the fuel valve in a sealing mode through the diaphragm, the upper end of the valve seat is connected with the inner wall of the top end of the air cavity through a spring, the lower end of the valve seat is provided with a valve ball matched with the pipe orifice of the input end of an oil return pipe, a group of oil inlet pipes are symmetrically arranged at the bottom of the fuel valve, a group of air guide pipes are symmetrically arranged at the top of the fuel valve, and an electric joint is arranged at the top of the fuel valve.

Further, the monitoring component comprises a distance sensor, a temperature and humidity sensor and an air pressure sensor which are arranged on the inner wall of the top end of the air cavity;

the number of the air ducts is even, the inside of each air duct is in a Tesla check valve structure, the conducting directions of two adjacent air ducts are opposite, the air ducts in the same conducting direction are communicated through the same connecting pipe, and the two connecting pipes are communicated through a circulating pipe;

the pressure stabilizing assembly comprises a compression pump, a plate radiator, a turbofan and a flow valve, wherein the compression pump and the plate radiator are connected in series on a circulating pipe, the compression pump is arranged at two ends of the plate radiator, the flow valve is arranged at two ends of the circulating pipe, and the turbofan is arranged at one side of the plate radiator.

Furthermore, the input end of the turbofan is connected with a hot air pipe and a cold air pipe in parallel, electromagnetic valves are arranged on the hot air pipe and the cold air pipe, the input end of the hot air pipe is arranged at the heat dissipation position of the engine, and the input end of the cold air pipe is arranged at the cold air port of the vehicle-mounted air conditioner;

the plate radiator is also provided with a dust removal component matched with the plate radiator.

Still further, the dust removal subassembly includes power module and electrode line, all be connected with an electrode line on every sheet heating panel of plate heat radiator, the electrode line is connected gradually with the electrical interface that corresponds on the power module.

Further, the polarities of the electrodes on any two adjacent heat dissipation plates are opposite, and the polarities of the electrodes on the heat dissipation plates are alternately changed along with time.

Further, the distance sensor adopts any one of laser and infrared rays, and is used for measuring the distance between the valve seat and the valve seat; the air duct, the connecting pipe and the circulating pipe are all made of heat insulation materials.

Furthermore, at least three hearing devices are embedded in a staggered manner on the inner side wall of the oil return pipe, the inside of the oil inlet pipe is also in a Tesla check valve structure, the input end of the oil inlet pipe is connected to the annular pipe, the annular pipe is communicated with the temperature control pipe, and throttle valves are arranged on the oil inlet pipe and the temperature control pipe.

Furthermore, the oil inlet pipe, the annular pipe and the temperature control pipe are all made of heat insulation materials, and the temperature control pipe is connected with a tube array heat exchanger in series.

Furthermore, the inside of the shell and tube heat exchanger is pre-filled with heat conducting liquid, a group of semiconductor refrigerating sheets and a group of ultrasonic vibrators are symmetrically distributed on the side wall of the shell and tube heat exchanger, the semiconductor refrigerating sheets and the ultrasonic vibrators are distributed in a staggered mode, and the polarity directions of any two adjacent semiconductor refrigerating sheets are opposite.

Furthermore, a group of ultrasonic sensors are distributed on the inner side wall of the liquid cavity in a mode that the central axis is taken as a symmetrical axis and the ultrasonic sensors are arranged in an equidistant circumferential array, and the detection direction of the ultrasonic sensors faces to the diaphragm.

Compared with the prior art, the application has the advantages and positive effects that:

the application sets up the monitoring assembly and steady voltage assembly on the fuel valve; the bottom of the fuel valve is symmetrically provided with a group of oil inlet pipes for conducting the internal liquid cavity of the fuel valve, the top of the fuel valve is symmetrically provided with a group of air guide pipes for conducting the internal air cavity of the fuel valve, the inside of each air guide pipe is in a Tesla one-way valve structure, the conducting directions of two adjacent air guide pipes are opposite, the air guide pipes in the same conducting direction are communicated through the same connecting pipe, and the two connecting pipes are communicated through a circulating pipe; the monitoring component comprises a distance sensor, a temperature and humidity sensor and an air pressure sensor which are arranged on the inner wall of the top end of the air cavity; the pressure stabilizing assembly comprises a compression pump, a plate radiator, a turbofan and a flow valve, wherein the compression pump and the plate radiator are connected in series on a circulating pipe, the compression pump is arranged at two ends of the plate radiator, the flow valve is arranged at two ends of the circulating pipe, and the turbofan is arranged at one side of the plate radiator; at least three hearing devices are embedded on the inner side wall of the oil return pipe in a staggered manner; in addition, a group of ultrasonic sensors are distributed on the inner side wall of the liquid cavity in a mode that the central axis is a symmetrical axis and the ultrasonic sensors are distributed in an equidistant circumferential array mode, and the detection direction of the ultrasonic sensors faces to the design of the diaphragm.

Firstly, the vehicle-mounted control system can accurately and real-timely measure the distance change between the valve seat and the valve seat through the distance sensor, so that the vibration frequency and amplitude of the valve seat are accurately and real-timely monitored; in the process, the vehicle-mounted control system drives the voltage stabilizing component through detection signals of the temperature and humidity sensor and the air pressure sensor, so that the temperature and the air pressure in the air cavity are kept unchanged, and errors in frequency and amplitude of vibration of the spring-driven valve seat caused by the influence of the temperature and the air pressure are eliminated.

Secondly, the vehicle-mounted control system can also detect whether bubbles appear in the oil return pipe through the sound listener, so that the bubbles are eliminated by adjusting the flow and the oil temperature of oil fed by the oil inlet pipe in a feedback mode (particularly, the shell and tube heat exchanger and the throttle valve are adjusted), and cavitation damage to the inner wall of the oil return pipe caused by the bubbles is avoided.

In addition, the vehicle-mounted control system can monitor whether the diaphragm has cracks or not through the ultrasonic sensor, so that accurate monitoring of the ageing degree of the diaphragm is realized.

Drawings

FIG. 1 is a pictorial view of the present application at a first viewing angle;

FIG. 2 is a pictorial view of the dedusting assembly and the voltage stabilizing assembly at a second view angle in accordance with the present application;

FIG. 3 is a visual illustration of the fuel valve of the present application at a third view angle;

FIG. 4 is a pictorial view, partially in section, of a fuel valve at a fourth view angle in accordance with the present application;

FIG. 5 is a partial cross-sectional view of the airway tube at a fifth view angle of the present application;

FIG. 6 is an enlarged view of area A of FIG. 1;

FIG. 7 is an enlarged view of region B of FIG. 2;

FIG. 8 is an enlarged view of region C of FIG. 4;

FIG. 9 is an enlarged view of region D of FIG. 4;

reference numerals in the drawings represent respectively:

100-fuel valve; 101-a movable member; 102-air cavity; 103-a liquid chamber; 104-valve seat; 105-membrane; 106-a spring; 107-an oil return pipe; 108-a valve ball; 109-an oil inlet pipe; 110-an airway; 111-electrical connectors; 112-connecting a tube; 113-a circulation pipe;

200-monitoring the assembly; 201-a distance sensor; 202, a temperature and humidity sensor; 203-an air pressure sensor;

300-voltage stabilizing component; 301-a compression pump; 302-plate radiator; 303-a turbofan; 304-a flow valve; 305-a hot air pipe; 306-a cold air pipe; 307-solenoid valve; 308-a heat dissipation plate;

400-dust removal assembly; 401-a power module; 402-electrode lines;

500-hearing aid;

600-loop pipe;

700-temperature control tube;

800-throttle valve;

900-tube array heat exchanger; 901-a semiconductor refrigerating sheet; 902-an ultrasonic vibrator;

1000-ultrasonic sensor.

Detailed Description

In order that the above objects, features and advantages of the application will be more clearly understood, a further description of the application will be rendered by reference to the appended drawings and examples. It should be noted that, without conflict, the embodiments of the present application and features in the embodiments may be combined with each other.

In the following description, numerous specific details are set forth in order to provide a thorough understanding of the present application, however, the present application may be practiced otherwise than as described herein, and therefore the present application is not limited to the specific embodiments of the disclosure that follow.

A monitoring device for a fuel control valve of the present embodiment, referring to fig. 1 to 9: including a monitoring assembly 200 and a pressure stabilizing assembly 300 disposed on the fuel valve 100.

(one)

The inside of the fuel valve 100 is divided into an upper air cavity 102 and a lower air cavity 103 which are mutually isolated through a movable part 101, the movable part 101 comprises a valve seat 104 and a membrane 105, the edge of the valve seat 104 is connected with the inner side wall of the fuel valve 100 in a sealing way through the membrane 105, the upper end of the valve seat 104 is connected with the inner wall of the top end of the air cavity 102 through a spring 106, the lower end of the valve seat 104 is provided with a valve ball 108 matched with the pipe orifice of the input end of an oil return pipe 107, the bottom of the fuel valve 100 is symmetrically provided with a group of oil inlet pipes 109, the top of the fuel valve 100 is symmetrically provided with a group of air guide pipes 110, and the top of the fuel valve 100 is provided with an electric joint 111.

Wherein the spring 106 is powered by the electrical connector 111 to provide a driving force for the cyclical movement of the valve seat 104.

Notably, are: the number of the air ducts 110 is even, the inside of each air duct 110 is in a Tesla check valve structure, the conducting directions of two adjacent air ducts 110 are opposite, the air ducts 110 with the same conducting direction are communicated through the same connecting pipe 112, and the two connecting pipes 112 are communicated through a circulating pipe 600113.

(II)

The monitoring assembly 200 includes a distance sensor 201, a temperature and humidity sensor 202, and an air pressure sensor 203 disposed on the top inner wall of the air chamber 102.

In this embodiment, the distance sensor 201 is a laser distance measuring sensor, so that the vehicle control system can accurately and real-time measure the distance change between the valve seat 104 and the distance sensor 201, thereby realizing accurate and real-time monitoring of the vibration frequency and amplitude of the valve seat 104.

The temperature and humidity sensor 202 has the following functions: on the one hand, the real-time temperature inside the air cavity 102 (especially the temperature of the spring 106) is monitored, and on the other hand, the tightness inside the air cavity 102 is monitored (particularly, whether the oil in the liquid cavity 103 permeates into the air cavity 102 or whether the outside water vapor enters the air cavity 102).

The air pressure sensor 203 is used for monitoring whether the air pressure inside the air cavity 102 is stable, so that the vehicle-mounted control system can perform targeted adjustment on the working states of the two compression pumps 301.

Notably, are: the air duct 110, the connecting pipe 112 and the circulating pipe 600113 are made of heat insulating materials, so that the air temperature flowing in the air duct 110, the connecting pipe 112 and the circulating pipe 600113 can be prevented from being interfered by the external temperature, and the accurate temperature control in the air cavity 102 is realized.

(III)

The pressure stabilizing assembly 300 comprises a compression pump 301, a plate radiator 302, a turbofan 303 and a flow valve 304, wherein the compression pump 301 and the plate radiator 302 are connected in series on a circulating pipe 600113, the compression pump 301 is arranged at two ends of the plate radiator 302, the flow valve 304 is arranged at two ends of the circulating pipe 600113, and the turbofan 303 is arranged at one side of the plate radiator 302.

Notably, are: the voltage stabilizing component 300 is used for maintaining the air pressure inside the air cavity 102 to be stable, so that interference errors caused to the expansion and contraction amount of the spring 106 when the spring is vibrated due to the unstable air pressure inside the air cavity 102 are avoided. In addition, the voltage stabilizing assembly 300 also plays a role in cooling the spring 106 (when the spring 106 is vibrated due to current flowing in, the temperature of the spring 106 is raised under the combined action of friction and resistance heating effect), so that the change of the stiffness coefficient of the spring 106 caused by the temperature rise is avoided, that is, the interference error caused by the temperature on the expansion and contraction amount of the spring 106 when the spring 106 vibrates is avoided.

The input of turbofan 303 connects in parallel with hot air pipe 305, cold air pipe 306, all is equipped with solenoid valve 307 on hot air pipe 305 and the cold air pipe 306, and the input of hot air pipe 305 sets up the heat dissipation department at the engine, and the input of cold air pipe 306 sets up the cold air mouth department at the vehicle air conditioner. The purpose of providing a hot air duct 305 and a cold air duct 306 at the input end of the turbofan 303 is: in some cold environments, too low a temperature may cause the spring 106 to be too low, and thus the spring 106 may become stiff and brittle, so that a certain heating and insulation of the spring 106 is required when the vehicle is just started, and when the vehicle is running stably, the spring 106 is precisely cooled down, so that the spring 106 is always maintained at a specified temperature (i.e. the stiffness coefficient of the spring 106 is maintained).

(IV)

Since the plate radiator 302 is electrostatically collected by friction with air when the plate radiator 302 is cooled by the turbo fan 303, the attached dust may reduce the heat exchanging performance of the plate radiator 302, and thus a dust removing assembly 400 is required to be provided on the plate radiator 302.

The dust removing assembly 400 comprises a power module 401 and electrode wires 402, each radiating plate 308 of the plate radiator 302 is connected with one electrode wire 402, and the electrode wires 402 are sequentially connected with corresponding electrical interfaces on the power module 401; and the polarities of the electrodes on any two adjacent heat dissipation plates 308 are opposite, and the polarities of the electrodes on the heat dissipation plates 308 alternate with time.

In this way, when the power module 401 supplies power to the plate radiator 302, a unidirectional uniform electric field is generated between two adjacent heat dissipation plates 308, dust attached to the heat dissipation plates 308 is polarized and flies toward the heat dissipation plates 308 of the anode, and meanwhile, the turbofan 303 provides an acting force perpendicular to the moving direction of the dust flying in the electric field, so that the flying track of the dust in the electric field deflects toward the air supply direction of the turbofan 303; then the polarity on the heat spreader plate 308 is changed and the dust repeats the above process; in this way, the heat dissipation plate 308 continuously changes polarity and is matched with the turbofan 303, so that the dust on the plate radiator 302 is directionally moved, and the plate radiator 302 is further dedusted.

(V)

At least three hearing devices 500 are embedded in a staggered manner on the inner side wall of the oil return pipe 107, the inside of the oil inlet pipe 109 is also in a Tesla check valve structure, the input ends of the oil inlet pipe 109 are connected to the annular pipe 600, the annular pipe 600 is communicated with the temperature control pipe 700, and the oil inlet pipe 109 and the temperature control pipe 700 are respectively provided with a throttle valve 800.

In this way, the vehicle-mounted control system can monitor whether bubbles exist in the oil return pipe 107 through the lifter, so that the flow and the oil temperature of oil fed by the oil inlet pipe 109 are timely adjusted to eliminate the bubbles, and cavitation damage of the bubbles to the inner wall of the oil return pipe 107 is avoided.

(six)

The oil inlet pipe 109, the annular pipe 600 and the temperature control pipe 700 are all made of heat insulation materials (in order to avoid the influence of external temperature on the temperature of fuel oil in the oil inlet pipe 109, the annular pipe 600 and the temperature control pipe 700), and the temperature control pipe 700 is connected with the tube array heat exchanger 900 in series.

The inside of the shell and tube heat exchanger 900 is pre-filled with heat conducting liquid, a group of semiconductor refrigerating sheets 901 and a group of ultrasonic vibrators 902 are symmetrically distributed on the side wall of the shell and tube heat exchanger 900, the semiconductor refrigerating sheets 901 and the ultrasonic vibrators 902 are distributed in a staggered mode, and the polarities of any two adjacent semiconductor refrigerating sheets 901 are opposite.

The semiconductor refrigeration piece 901 is used for realizing accurate temperature control of the heat-conducting liquid, so that the accurate temperature control of the fuel oil is indirectly realized through the heat-conducting liquid, and the fuel oil in the liquid cavity 103 is kept at a specified low temperature all the time to avoid cavitation damage in the oil return pipe 107.

(seven)

Since the diaphragm 105 inevitably generates cracks or even breaks on the diaphragm 105 as the working time increases, which is disadvantageous for safe and stable operation of the vehicle, a group of ultrasonic sensors 1000 are distributed on the inner side wall of the liquid chamber 103 in such a manner that the central axis thereof is a symmetrical axis and the ultrasonic sensors 1000 are arranged in an equally spaced circumferential array, and the detection direction of the ultrasonic sensors 1000 is directed toward the diaphragm 105 (since the liquid chamber 103 is always filled with fuel, this makes it possible for the ultrasonic sensors 1000 to monitor whether the surface of the diaphragm 105 is cracked or not), thereby monitoring whether the diaphragm 105 is cracked or not by the ultrasonic sensors 1000.

The present application is not limited to the above-mentioned embodiments, and any equivalent embodiments which can be changed or modified by the technical content disclosed above can be applied to other fields, but any simple modification, equivalent changes and modification made to the above-mentioned embodiments according to the technical substance of the present application without departing from the technical content of the present application still belong to the protection scope of the technical solution of the present application.

Claims

1. A monitoring device for a fuel control valve, characterized by: comprises a monitoring component (200) and a pressure stabilizing component (300) which are arranged on the fuel valve (100);

the inside of the fuel valve (100) is divided into an air cavity (102) and a liquid cavity (103) which are isolated from each other up and down through a movable part (101), the movable part (101) comprises a valve seat (104) and a membrane (105), the edge of the valve seat (104) is connected with the inner side wall of the fuel valve (100) in a sealing way through the membrane (105), the upper end of the valve seat (104) is connected with the inner side wall of the top end of the air cavity (102) through a spring (106), the lower end of the valve seat (104) is provided with a valve ball (108) matched with an inlet pipe orifice of an oil return pipe (107), the bottom of the fuel valve (100) is symmetrically provided with a group of oil inlet pipes (109), the top of the fuel valve (100) is symmetrically provided with a group of gas guide pipes (110), the top of the fuel valve (100) is provided with an electric joint (111), and the spring (106) is powered by the electric joint (111) so as to provide driving force for the circulating movement of the valve seat (104);

the monitoring assembly (200) comprises a distance sensor (201), a temperature and humidity sensor (202) and an air pressure sensor (203) which are arranged on the inner wall of the top end of the air cavity (102);

the number of the air ducts (110) is even, the inside of each air duct (110) is in a Tesla check valve structure, the conducting directions of two adjacent air ducts (110) are opposite, the air ducts (110) with the same conducting direction are communicated through the same connecting pipe (112), and the two connecting pipes (112) are communicated through a circulating pipe;

the pressure stabilizing assembly (300) comprises a compression pump (301), a plate radiator (302), a turbofan (303) and a flow valve (304), wherein the compression pump (301) and the plate radiator (302) are connected in series on a circulating pipe, the compression pump (301) is arranged at two ends of the plate radiator (302), the flow valve (304) is arranged at two ends of the circulating pipe, and the turbofan (303) is arranged at one side of the plate radiator (302);

the distance sensor (201) adopts any one of laser and infrared rays, and the distance sensor (201) is used for measuring the distance between the valve seat (104) and the valve seat; the air duct (110), the connecting pipe (112) and the circulating pipe are all made of heat insulation materials;

at least three hearing devices (500) are embedded in the inner side wall of the oil return pipe (107) in a staggered mode, the inside of the oil inlet pipe (109) is also in a Tesla one-way valve structure, the input ends of the oil inlet pipe (109) are connected to the annular pipe (600), the annular pipe (600) is communicated with the temperature control pipe (700), and throttle valves (800) are arranged on the oil inlet pipe (109) and the temperature control pipe (700);

a group of ultrasonic sensors (1000) are distributed on the inner side wall of the liquid cavity (103) in a mode that the central axis is taken as a symmetrical axis and the ultrasonic sensors are arranged in an equidistant circumferential array, and the detection direction of the ultrasonic sensors (1000) faces to the diaphragm (105).

2. The monitoring device for the fuel control valve according to claim 1, wherein the input end of the turbofan (303) is connected with a hot air pipe (305) and a cold air pipe (306) in parallel, electromagnetic valves (307) are arranged on the hot air pipe (305) and the cold air pipe (306), the input end of the hot air pipe (305) is arranged at a heat dissipation position of an engine, and the input end of the cold air pipe (306) is arranged at a cold air port of a vehicle-mounted air conditioner;

the plate radiator (302) is also provided with a dust removal component (400) matched with the plate radiator.

3. The monitoring device for a fuel control valve according to claim 2, wherein the dust removing assembly (400) comprises a power module (401) and electrode wires (402), each radiating plate (308) of the plate radiator (302) is connected with one electrode wire (402), and the electrode wires (402) are sequentially connected with corresponding electrical interfaces on the power module (401).

4. A monitoring device for a fuel control valve according to claim 3, characterized in that the polarities of the electrodes on any adjacent two of said heat radiating plates (308) are reversed and the polarities of the electrodes on said heat radiating plates (308) alternate with time.

5. The monitoring device for the fuel control valve according to claim 1, wherein the oil inlet pipe (109), the loop pipe (600) and the temperature control pipe (700) are made of heat insulation materials, and the temperature control pipe (700) is connected with a tubular heat exchanger (900) in series.

6. The monitoring device for a fuel control valve according to claim 5, wherein the inside of the tube nest heat exchanger (900) is pre-filled with a heat conducting liquid, a group of semiconductor refrigerating sheets (901) and a group of ultrasonic vibrators (902) are symmetrically distributed on the side wall of the tube nest heat exchanger (900), the semiconductor refrigerating sheets (901) and the ultrasonic vibrators (902) are distributed in a staggered mode, and the polarities of any two adjacent semiconductor refrigerating sheets (901) are opposite.