In the car engine, an oil pump is used to create the necessary pressure in the lubrication system. Through pressure, all parts and components of the power unit that are in motion are lubricated. In the system itself, where there is a dry sump, the pump also does the work. It carries out the function of transporting oil to the tank from the crankcase of the motor. The pump is driven by a crankshaft or drive shaft. According to the type of control, oil pumps can be divided into regulated and unregulated. What are their differences? A controllable oil pump can maintain a constant pressure level due to a change in capacity. If an unregulated mechanism is used, then a constant pressure force is maintained by an oil pressure reducing valve. Let's look at what these elements are for, how they are designed, and how they work.
By the way, despite its small size, this device plays a very important role in the engine and lubrication system . If this valve is clogged, there is a risk of turning the liners in the motor. This threatens engine failure.
What is a pressure reducing valve?
This element is nothing more than a hydraulic or pneumatic throttle. It operates in automatic mode. The element is designed to maintain a pressure of a certain force at the outlet. There are several types of mechanisms.
This is an oil pressure reducing valve controlled by a pneumatic or electric actuator or a direct acting element. The latter does not need external power supplies and drives.
Pressure reducing valve functions
The first and main task that the oil pressure pressure reducing valve solves is the creation and maintenance of a certain pressure level. It must be constantly monitored. Any, even the most minimal excesses of this value lead to sad consequences. Important engine components may fail. But it is also impossible for the pressure to be too low. An insufficient level will lead to overheating of the components and engine parts. There will be oil starvation.
To avoid all these problems, engineers designed and built up a pressure reducing valve. At first glance, it might seem that this is a
simple mechanism that is actually not needed. But this is not at all true. If there is no such valve in the engine, then the normal operation of the power unit becomes simply impossible. The main purpose of this mechanism is to constantly monitor the pressure force of the oil in the system, as well as to weaken or increase the parameters if necessary. Pressure adjustment and the principle of the valve are to open and close the oil passage. When the mechanism is open, the level will not drop. If the element is closed, then if the pressure drops, the lubrication system will be restored.
Principle of operation
Considering the device of this mechanism, it is impossible not to mention the principle of action by which the valve works. The algorithm is quite simple. The main organ through which the process of adjusting the pressure force is carried out is a special stop bolt. It is this element that presses on the spring and thereby presses the pressure reducing valve of the oil pressure directly to the hole.
After increasing the pressure in the system (and the permissible level will be lower), the oil will overcome the force of the spring. Thus, the valve is squeezed back. Due to this, the oil will go into a special container or compartment. After the pressure level has stabilized and the level has returned to normal by means of a spring, the valve will return to its original state. The engine will be able to continue to operate normally. The fuel pressure reducing valve also functions according to the same principle. He performs the same tasks. However, it is installed together with fuel injection pump on diesel engines.
About design
This mechanism is arranged quite simply. It is a small-sized casing in which there are special channels for the movement of oil. The design also includes a spring, stem and regulator. The latter is a small ball or a piston. The operation of the pressure reducing valve is reduced to the timely termination and prevention of pressure growth in the lubrication system of the car. The main feature of this system is that the device, with the simplest design possible, can effectively do its job. The element fails very rarely.
Types of valves for the device
Modern industry offers the device in two versions. In the first case, this mechanism can be located in the body of the oil pump. In the second element is a separate part. It is possible to dismantle the mechanism, repair, as well as adjust the pressure relief valve. The system is well thought out. But even such simple and reliable mechanisms sometimes fail. Problems in the operation of an element can cost a lot to the car owner.
Where is it located?
Beginning car owners, and sometimes experienced ones, do not know where the pressure relief valve is located.
You can find this part in the lower front of the engine block. Most often, the valve is located behind the alternator drive pulley. Sometimes this element is installed directly on the
oil filter housing
.Set pressure
So, it became more clear what this mechanism is. But how to determine that the pressure in the oil system is changing? And what should be the optimal value? Normal pressure values are indicated in the user manual. Each vehicle has its own parameter.
For example, at Tavria, the valve operates at 0.55 MPa. At about the same level, the VAZ-2110 oil pressure relief valve will work. How to measure the pressure level? To do this, use a special liquid-type pressure gauge. It plugs into the seat for the pressure sensor. Before measurements, the motor must be well warmed up. Measurements are taken with the engine running. For example, take the oil pressure relief valve, 406 engine. Here, the optimal parameter is 4.6 kgf / cm
2 .
Typical malfunctions
There are several basic and common problems that can occur with pressure reducing valves. They appear in two aspects. The first case is that the valve cannot maintain a normalized oil pressure level. Most often, such malfunctions occur due to mechanical breakdowns. The most vulnerable and problematic element in this system is the spring. During operation, and especially long-term operation, the spring is stretched. Due to this, the valve will open unauthorized with minimal levels of increase in lubricant pressure. Oil simply will not be able to get to most of the components and mechanisms of the power unit. This reduces their resource.
Among the main causes of malfunctions that occur with the spring, operational wear, improper installation of the element after major repairs, and errors in the installation of the valve can be highlighted.
In the second embodiment, the valve does not open when a high or maximum pressure is reached. This happens due to clogging of the oil channel. The reason is a long period of operation. As a result, the valve will wedge when high pressures are reached. As a result, the item will not open. The result - the inability to lubricate moving and rubbing mechanisms and components in the engine and their destruction. The cause of this malfunction is an untimely oil change. This can be explained very simply, but fixing the problem is a difficult process. The smallest particles of dirt will accumulate on the surface of the valve, thereby increasing the size of the growths. Due to poor flushing, chips and other debris will accumulate in the valve channels.
Repair and adjustment
To understand whether the valve is working and whether it can be operated in the future, it is necessary to dismantle the device and disassemble it. Thus, it is possible to diagnose all the details of the mechanism. If deposits have formed on the valve body, they are cleaned with a mixture of gasoline and kerosene. You can use liquid to flush carburetors. You should also carefully diagnose the spring. If it is stretched or there are signs of deformation on it, the part must be replaced.
When the valve is fully inspected and moved, it is necessary to check whether it works. This is done with a simple pressure on the piston or ball. If it is necessary to apply force for indentation, and after the piston returns, then the mechanism is working. The adjustment process is carried out after installing the mechanism in the pump housing. Adjust the device by compressing or releasing the spring using the adjusting or stop screw. In parallel with the rotation of the screw, the oil pressure is measured with a liquid manometer. It is necessary to adjust on an unreleased power unit. But to make measurements, on the contrary, on a running motor.