It's time to deal with such a device as an electric valve. Such devices are probably available in almost every apartment - in washing machines. But besides washing machines, valves can and are used in water supply systems, for example, for emergency shutdown of water, or in automation systems for water control. So How How does the solenoid valve work and work?
Of course, there are different designs, but let’s look at this one:
I bought it on eBay, but I also saw it in our stores. This is a normally closed electric valve with a 220V coil, i.e. Now it doesn't let water through. If you apply voltage to the coil, the water will be able to pass through. First, let’s disassemble the valve, and then I’ll explain how this miracle technology works.
There is an electromagnet under the cap
We see in clear Chinese that the coil is 220V AC. On the other side there is an arrow indicating the direction of fluid movement and an inlet filter plug:
Let's start by unscrewing the underwater pipe with the inlet filter:
The filter is a plastic insert with small holes, although such a “mesh” will provide great resistance to liquid, so this is a design disadvantage.
There is a check valve at the outlet that prevents the reverse movement of the liquid.
Now let's unscrew the electromagnet. We will see the following:
The insert into the coil is pulled out and there is an anchor with an elastic band at the end.
The body has a rubber membrane and special inserts and holes. The hole is where the spring is and in the center.
Only the body remains, there is nothing else to disassemble. Here's what the case itself is like:
We have it on the table :)
Now we know what's inside him. You just need to figure out how it works. To explain the principle of operation, I drew the following diagram:
Designations: 1 – liquid inlet channel; 2 – membrane; 3 – hole in the membrane (where the spring is); 4 – camera on the reverse side; 5 – anchor; 6 – armature spring; 7 – elastic band on anchor; 8 – central hole in the membrane; 9 – outlet channel for liquid.
In the normal state, when the electromagnet is turned off, the armature 5 is attached to the membrane by the spring 6, and the rubber tip 7 covers the central hole 8. The liquid is supplied to the input channel 1 under pressure p1, and through hole 3 enters chamber 4. The same is created in the chamber pressure, i.e. p1. Therefore, the liquid acts on the membrane from above and below with the same pressure, but the area of action of the force on the membrane is 3 different - it is larger from above, and, therefore, the force is greater. The membrane is pressed by fluid pressure. I would like to note right away that the valve will only work when the pressure at the outlet is less than at the inlet, which is why there is a check valve there.
What happens when voltage is applied to an electromagnet? The anchor 5 is retracted and the central hole 8 opens, the liquid flows into channel 9, the pressure is equalized above and below the membrane and under the influence of the flow it moves upward, thereby allowing the liquid to flow directly from channel 1 to channel 9, i.e. to the exit.
When the electromagnet is turned off, under the action of a spring, the armature is pressed against the membrane and closes the central hole. The pressure in channel 9 drops and the membrane is pressed downwards, blocking the flow of liquid.
One of the most important control elements of a water pumping station is the pressure switch. It provides automatic switching on and off of the pump, controlling the supply of water to the tank according to specified parameters. There are no clear recommendations on what the maximum values of the lower and upper pressures should be. Each consumer decides this individually within the limits of acceptable standards and instructions.
Design and principle of operation of a water pressure switch
Structurally, the relay is made in the form of a compact block with springs of maximum and minimum pressure, the tension of which is regulated by nuts. The membrane connected to the springs reacts to changes in pressure force. When the minimum value is reached, the spring weakens; when the maximum level is reached, it compresses more strongly. The force exerted on the springs causes the relay contacts to open (close), turning the pump off or on.
The presence of a relay in the water supply allows you to ensure constant pressure and the required water pressure in the system. The pump is controlled automatically. Correctly set ones ensure its periodic shutdown, which contributes to a significant increase in trouble-free service life.
Sequence of work pumping station under relay control is as follows:
- The pump pumps water into the tank.
- The water pressure is constantly increasing, which can be monitored by the pressure gauge.
- When the set maximum pressure level is reached, the relay is activated and turns off the pump.
- As the water pumped into the tank is consumed, the pressure decreases. When it reaches the lower level, the pump will turn on again and the cycle will repeat.
Device diagram and components of a typical pressure switch
Basic parameters of relay operation:
- Lower pressure (switch-on level). The relay contacts that turn on the pump close and water flows into the tank.
- Upper pressure (shutdown level). The relay contacts open and the pump turns off.
- Pressure range is the difference between the two previous indicators.
- The value of the maximum permissible shutdown pressure.
Setting up the pressure switch
During the assembly of the pumping station Special attention is paid to setting up the pressure switch. Ease of use, as well as the trouble-free service life of all components of the device, depend on how correctly its limit levels are set.
At the first stage, you need to check the pressure that was created in the tank during the manufacture of the pumping station. Typically, at the factory, the switch-on level is set at 1.5 atmospheres, and the switch-off level is 2.5 atmospheres. They check this with an empty tank and the pumping station disconnected from the power supply. It is recommended to check with an automotive mechanical pressure gauge. It is housed in a metal case, so the measurements are more accurate than using electronic or plastic pressure gauges. Their readings can be affected by both the room temperature and the battery charge level. It is desirable that the pressure gauge scale limit be as small as possible. Because on a scale of, for example, 50 atmospheres, it will be very difficult to accurately measure one atmosphere.
To check the pressure in the tank, you need to unscrew the cap that closes the spool, connect the pressure gauge and take a reading on its scale. The air pressure should continue to be checked periodically, for example once a month. In this case, the water must be completely removed from the tank by turning off the pump and opening all taps.
Another option is to carefully monitor the pump shut-off pressure. If it increases, this will mean a decrease in air pressure in the tank. The lower the air pressure, the greater the supply of water can be created. However, the pressure spread from a completely filled to an almost empty tank is large, and all this will depend on the preferences of the consumer.
Having chosen the desired operating mode, you need to set it by bleeding off excess air, or pump it up additionally. It must be borne in mind that the pressure should not be reduced to less than one atmosphere, nor should it be over-pumped. Due to the small amount of air, the rubber container filled with water inside the tank will touch its walls and be wiped. And excess air will not make it possible to pump in a lot of water, since a significant part of the tank’s volume will be occupied by air.
Setting the pump on and off pressure levels
Which are supplied assembled, the pressure switch is pre-configured according to optimal option. But when installing it from various elements at the site of operation, it is necessary to configure the relay. This is due to the need to ensure an effective relationship between the relay settings and the tank volume and pump pressure. In addition, it may be necessary to change the initial setting of the pressure switch. The procedure should be as follows:
In practice, the power of the pumps is chosen such that it does not allow pumping the tank to the extreme limit. Typically, the cut-out pressure is set a couple of atmospheres above the switch-on threshold.
It is also possible to set pressure limits that differ from the recommended values. In this way, you can set your own version of the operating mode of the pumping station. Moreover, when setting the pressure difference with a small nut, one must proceed from the fact that the initial reference point should be the lower level set by the large nut. Exhibit top level only within the limits for which the system is designed. In addition, rubber hoses and other plumbing fixtures also withstand pressure, not higher than the calculated one. All this must be taken into account when installing a pumping station. In addition, excessive water pressure from the tap is often completely unnecessary and uncomfortable.
Adjusting the pressure switch
Adjusting the pressure switch is practiced in cases where it is necessary to set the upper and lower pressure levels to the specified values. For example, you need to set the upper pressure to 3 atmospheres, the lower pressure to 1.7 atmospheres. The adjustment process is as follows:
- Turn on the pump and pump water into the tank until the pressure on the pressure gauge reaches 3 atmospheres.
- Turn off the pump.
- Open the relay cover and slowly turn the small nut until the relay operates. Rotating the nut clockwise means increasing pressure, in the opposite direction means decreasing. The upper level is set to 3 atmospheres.
- Open the tap and drain the water from the tank until the pressure on the pressure gauge reaches 1.7 atmospheres.
- Close the tap.
- Open the relay cover and slowly rotate the large nut until the contacts operate. The lower level is set at 1.7 atmospheres. It should be slightly greater than the air pressure in the tank.
If the pressure is set to high to turn off and low to turn on, the tank is filled with more water and there is no need to turn on the pump often. Inconveniences arise only due to the large pressure drop when the tank is full or almost empty. In other cases, when the pressure range is small and the pump often has to be pumped up, the water pressure in the system is uniform and quite comfortable.
In the next article you will learn the most common connection schemes.
Sit back, we will talk about one of the most mysterious parts of the scooter - the starting enrichment. This detail is small, but very important. It is this that helps start a cold scooter engine without hemorrhoids in any weather. Only thanks to her, the scooter starts easily with half a kick, and for those who don’t, it means their hands are growing crookedly. Thanks to her, my dear, the scooter does not shoot into the muffler like domestic motorcycles, but idles quietly and smoothly. Thank the Japanese for inventing this thing! - I say in all seriousness.
So, what does it mean - launcher enrichment agent? This is essentially an additional small carburetor, standing parallel to the main one. It is connected to the main carburetor by three channels - air, emulsion and fuel, drilled in its body. The air is taken in before the throttle valve, the emulsion (mixture) is supplied after it, directly into the carburetor outlet pipe. Gasoline is taken from a common float chamber. Thus, with some stretch, the enrichment can be considered an independent device. It’s a stretch, because it is, nevertheless, structurally inseparable from the carburetor.
Now let's look at the drawing.
The carburetor has a small additional fuel chamber 7, which is connected to the main float chamber 8 through the start jet 9. The tube from chamber 7 leads to the mixing chamber into which air is supplied and from which the air-gasoline mixture goes into the engine. A valve 6 can move in the mixing chamber, similar to a carburetor throttle valve, only much smaller in size. Just like in the throttle, in launcher The damper contains a spring-loaded needle, which closes the fuel channel when the damper is lowered. When starting a cold engine, the damper is raised (open). At the first engine revolutions, a vacuum is created in the emulsion channel and gasoline located in chamber 7 is sucked into the engine, causing a strong enrichment of the mixture and facilitating the first flashes in the engine.
After the engine has started, but has not yet warmed up, it needs a rich mixture. The enricher works like a parallel carburetor; gasoline enters it through jet 9, mixes with air and enters the engine. When the engine is running alternating current from its generator it is always supplied to the contacts of the ceramic heater 2 of the thermoelectric valve of the starting system. The heater warms up the actuator 3. Inside it, obviously, there is a gas or liquid boiling at a low temperature and a piston connected to the rod 4. When the actuator is heated, the rod gradually extends by 3-4 mm and through the pusher 5 sets the damper in motion. Valve body 1 is wrapped in thermal insulation (polyethylene foam) and covered with a rubber boot.
Thus, the engine warms up along with the thermoelectric valve and the mixture gradually becomes leaner. After 3-5 minutes the damper closes completely and the degree of enrichment of the mixture on a hot engine is set only by the system idle move carburetor When the engine stops, heating of the valve stops, the damper drive cools down and under the action of spring 10, pusher 5, rod 4 and damper 6 return to their original position, opening the channels for subsequent start-up. Cooling down and returning to its original position also occurs within a few minutes.
This enricher design is used on almost all modern scooters. Older models may use a design without an electric heater; heat is transferred to the drive through a copper heat-conducting cylinder directly from the engine cylinder. Sometimes, there is also a manual drive of the damper through a cable from the handle on the steering wheel (“Choke”).
Now the “diseases” of the system
1. The air channel may be clogged with dirt. In this case, the mixture becomes very rich, even after the engine has warmed up.
2. The jet may be clogged with dirt. It is very thin and this happens quite often. Wherein enrichment agent It works the other way around - it leans the mixture, making starting difficult.
3. Contact with the heater “tablet” is broken. The valve does not heat up and does not close. Engine It runs all the time on an over-enriched mixture and does not develop the required power. The resistance at the valve contacts is easy to measure; it should be in the region of several ohms.
4. The mustache is broken off
To control the fuel supply, a gas equipment solenoid valve is provided in the gas equipment system on the car. Its main function is to open and close the flow of gas from the cylinder to.
In this article we will look at the types, design, installation options, main faults and methods of repairing the solenoid valve of a gas cylinder installation.
The 2nd generation HBO device on a carburetor engine provides for the presence of two electric valves:
- gasoline (for supplying/cutting off standard fuel);
- gas valve (EGV).
Scheme gas system for injection engines (GBO 2-4 generations), where gasoline is supplied to the cylinders using injectors, only a gas valve is assumed.
Gas and petrol valves
Design and principle of operation
The design of all EGCs is identical:
- Electromagnetic coil (solenoid).
- Sleeve (core tube).
- Spring.
- Core (anchor).
- Rubber cuff.
- O-rings.
- Valve body with seat.
- Inlet and outlet.
- Coarse fuel filter.
Gas valve device
The operating principle of all devices is also the same. The only difference is that the solenoid valve is controlled using the gas system ECU (electronic control unit). In the second generation, signals to the EGC come from the equipment power button.
If there is no power to the coil contacts, the core, under the influence of a spring, presses the cuff to the seat, so the valve is in the closed state. As soon as voltage (12 V) appears at the solenoid terminals, under the influence magnetic field the anchor moves along the sleeve, thereby unlocking the valve.
Installation and connection
According to the type of location, gas valves are:
- Remote;
- built-in
A remote gas gas solenoid valve is usually mounted in the engine compartment of a car, or placed directly on the gas reducer through an adapter. Built-in, located in the evaporator housing.
Built-in and remote electrovalves
Sometimes, for greater safety, two valves are installed at once, after the multivalve (in the flow line before the evaporator) and on the gearbox.
The connection is made using gas equipment wiring, according to the diagram that is included in the gas equipment kit. When the harness is laid from the control button to the solenoid. During the process, the cable runs from the HBO control unit to the valve. There is no difference where to connect the terminals on the coil.
Possible faults
Often, due to breakdowns of the gas electric valve, malfunctions occur in the operation of gas equipment. Such as:
- Unstable engine operation at idle;
- Gas system failure due to lack of pressure.
Causes of malfunctions due to which the unit does not hold and allows gas to pass through:
- clogged;
- jamming/sticking of the core;
- wear (loss of properties, weakening) of the return spring;
- failure of the rubber seal or valve seat;
- coil malfunction.
In a carburetor circuit where gasoline electric power is present. valve, in addition to everything else, increased consumption/leakage of gasoline or failure of the engine to operate on standard fuel may be added.
You can detect a leak by removing the gas hose from the carburetor with the car running or by purging the valve (in a closed state) with a pump/compressor.
Do-it-yourself gas turbine solenoid valve repair
To repair the solenoid valve, you must first stock up on a repair kit and a set of tools.
However, in some cases, regular cleaning/flushing of the solenoid armature helps.
So, to repair a gas valve, the first step is to tighten the valve to shut off the fuel supply from the cylinder. Then drain the remaining gas from the supply line and remove the assembly.
- cover the filter element and remove the element itself;
- coil;
- solenoid sleeve with core.
After cleaning all the parts, you need to troubleshoot them and, if necessary, replace them.
It is important that if the system uses copper lines, oxide particles from such tubes are most often the cause of sticking of the solenoid armature.
Also, do not forget about the frequency of replacing the filter element. It is recommended to change the filter once every 7-10 thousand km. mileage
It is advisable to check the resistance of the coil with a multimeter and compare the parameters with those indicated on its body (the norm is about 9-13 Ohms). In addition, rubber seals and the valve seat have their own resource.
Gas equipment for cars, abbreviated as LPG, is the latest, affordable and effective means of saving car fuel, increasing engine life and reducing the amount of harmful substances released into the environment - all in one bottle. Every year, the unfavorable situation in the oil price market and the general deterioration in the quality of gasoline cause a steady desire of car owners to switch to more economical and engine-friendly operating principles. The ability to refuel with liquefied propane and petroleum gas (methane) has been known since the mid-19th century; it appeared simultaneously with gasoline and diesel engines internal combustion and developed in parallel. But only from the late 70s of the XX century, gas equipment became truly in demand, and a developed infrastructure of gas stations and car service stations appeared.
In general, it includes gas cylinder, from which the gas line extends, at the end closes the multivalve. Behind it, a geared evaporator converts the gas into working condition and accumulates it in portions in the manifold and injects it into the engine through separate injectors. The process is controlled by a control unit connected to the on-board computer (in more advanced models).
Classification
Today, a huge number of specialized manufacturers offer a wide range of gas equipment for both carburetor and injection types of engines of any complexity and configuration. Conventionally, all systems are divided into generations, each of which has its own operation and degree of automation of adjustment:
- The first generation is the vacuum principle of dosing each gas portion. A special mechanical valve reacts to the vacuum that occurs in the car's inlet manifold when the engine is running and opens the way for gas. A primitive device for simple carburetor systems does not have any feedback from the engine electronics, fine adjustment and other optional add-ons.
- Second-generation gearboxes are already equipped with the simplest electronic brains, which, by communicating with the internal oxygen sensor, act on a simple solenoid valve. This operating principle allows the car to not only drive as fast as it can, but also regulates the composition of the gas-air mixture, striving for optimal parameters. A practical and still widespread device among owners of carburetor cars, but in Europe it has already been banned for use since 1996 high level environmental pollution.
- The demand for representatives of the transitional third generation is quite low. The operation of these high-tech systems is based on autonomous software, creating their own fuel cards. Gas is supplied by a special built-in injector to each cylinder separately. The internal software emulates the operation of gasoline injectors using its own hardware capabilities. The design turned out to be not very successful; the weak processor of the unit froze, causing failures in the functioning of the mechanism. The idea was lost when a newer and more sophisticated class of gas equipment appeared.
- The most common gearboxes today are those with split injection of the gas-air mixture. This is a completed 3rd generation project, but uses standard petrol maps of the car in the configuration program, which does not burden the computing power of the control unit. There is a separate line of generation 4+, developed for direct-flow direct fuel injection systems directly into the FSI engine.
- The newest product being introduced into the auto market is the 5th generation. The key feature of the operating principle is that the gas does not evaporate in the gearbox, but is pumped as liquid directly into the cylinders. Otherwise, this is full compliance with the 4th generation: split injection, use of data from the factory fuel map, automatic switching mode from gas to gasoline, etc. Another advantage that can be noted is that the equipment is fully compatible with current environmental standards and the latest on-board diagnostics .
Solenoid multivalve
In all these HBO systems, regardless of the class and principle of operation, a device such as a multivalve plays a key role. It is he who allows and blocks gas, filters the composition of the mixture, selecting harmful substances and impurities (which is why the built-in filter needs to be replaced regularly).
Initially, a conventional mechanical valve had only a shut-off function and was tightly welded directly to the cylinder. The first generation of vacuum-type equipment begins to use a valve with an additional vacuum membrane, which plays the role of a vacuum level sensor in the manifold. Further complexity of the design and general unification of cylinder necks from various manufacturers led to an increase in the number of simultaneously performed work operations. A modern electromagnetic multivalve for cars consists of a whole set of built-in valves connected feedback sensors with an electronic control unit.
Functions of devices integrated into multivalves
- Protects the cylinder from gas leakage
When the cylinder is filled to 80% with liquefied gas, the filling valve shuts off the fuel supply. Complete filling of the actual volume of the cylinder is unacceptable according to safety requirements - under the influence of some external factors, for example, a sharp change in the temperature of the environment, the gas can expand sharply, which can be fraught with dangerous consequences when fully loaded (the container can even explode), that is, when the pressure reaches at 25 atmospheres (standard storage device)
- Adjusting the supply level to the gas main
There is a special anti-slam high-speed valve on the gas pipeline that regulates the rate of fuel supply into the gas pipeline. Additionally, it performs another safety function - it prevents potential leakage if deformation or breakage of the car line occurs.
Emergency fire protection for a gas-powered vehicle consists of: separate element multi-valve: the fuse will release fuel through the ventilation block outside the machine if a sudden and strong increase in temperature (hence, excess pressure in the system) signals the beginning of a fire in the immediate vicinity of the gas equipment.
The presence of a fuse automatically transfers the safety category from class B to class A. It is strictly prohibited to install a gas multivalve without such a fuse on a cylinder with a capacity of more than 50 liters.
- Measuring valve
To indicate the amount of gas remaining in the system, another separate filling valve is used, the operation of which is associated with a corresponding magnetic sensor. In injection systems of 3 or more generations, at the moment of automatic switching to gasoline if there is a shortage of alternative fuel, it is the gas measuring valve that closes the line.
- Check valve
The second filling fuse operates only on gas inlet and prevents it from returning back during refueling.
- Backup shut-off valves
Safety comes first: no matter how modern and computerized the equipment is, failures, malfunctions, and emergency situations are always possible. In a situation that requires decisive action from the driver of the car, two manual valves can be useful, which, if absolutely necessary, are always capable of forcibly shutting off the gas flow in the line.
Filtration properties of a multivalve
The standard design of HBO involves placing a multi-valve in a ventilation unit, which is located directly on the cylinder in a separate removable container. Special hoses go out to separate impurities and, in case of any danger, release the gas away from the car interior.
It is recommended to replace the air filter equipped with the ventilation box every 15-20 thousand kilometers to avoid severe clogging.
Manufacturers
The electromagnetic multivalve, along with the gearbox and control unit, is the most important component of gas equipment, on which the safe operation of the car depends, so choosing it should be taken as seriously as possible. All major gas equipment manufacturers also offer a multivalve in their range, suitable for different generations and shapes of the gas cylinder, as evidenced by the Cil (cylindrical) or Tor (toroidal) markings on the body. Italian brands are considered the highest quality, of which BRC, Tomasetto, Lovato, Atiker can be noted.