The governor is mainly a component used to adjust the s […]
The governor is mainly a component used to adjust the speed. It is an automatic adjustment device that can change according to the load of the diesel engine, so that the fuel supply of the fuel injection pump can be automatically increased or decreased, so that the diesel engine can Even RPM operation.
Typically, the car's governor is installed around the driver, between the two front seats. Applied to ordinary diesel engines, because mechanical diesel engines are more likely to cause flameout or loss of speed, which makes the car uncontrollable, it is necessary to use a governor to adjust the engine speed of the car accordingly. With the development of the automobile industry, the mechanical diesel engine has gradually faded out of the automobile industry, and now the main use is the electronic fuel injection diesel engine, which mainly uses the computer board to control the engine speed. The main working principle of the governor is that when the load decreases, the centrifugal force of automatic slack adjuster Factory the fly ball gradually increases, and the rotational speed of the drive shaft driven by the crankshaft also increases gradually, further pushing the speed rod to move to the right. With the movement of the speed rod, the rocker rotates counterclockwise with the crankshaft node as the center, the spool valve moves to the right, and the pressure oil also enters the right side of the servo cylinder at the same time. At this time, the left space of the oil cylinder is connected to the low-pressure oil circuit through the oil hole, and the oil is discharged. When the speed returns to the original value, the spool valve will also return to the corresponding position.
According to how it works
According to the different working principles, it can be divided into mechanical, pneumatic, hydraulic, mechanical-pneumatic composite, mechanical-hydraulic composite and electronic and other forms. But at present the most widely used is the mechanical governor, which is simple in structure, reliable in operation and good in performance.
The hydraulic governor adds a hydraulic amplifying element (hydraulic servo) between the sensing element and the oil quantity adjusting mechanism, so that the output signal of the sensing element is transmitted to the oil quantity adjusting mechanism through the amplifying element, so it is also called an indirect action adjusting mechanism. speeder.
The hydraulic amplifying element has the function of amplifying and executing, and is mainly composed of two parts: control and execution.
Hydraulic governor without feedback
It works as follows:
When the load decreases, the rotational speed of the drive shaft driven by the crankshaft increases, and the centrifugal force of the flying ball increases, pushing the speed rod to the right.
Governor (Picture 1)
Governor (Picture 1)
Then, the rocker rotates counterclockwise around point A, the spool valve moves to the right, and the pressure oil enters the right space of the servo cylinder. At the same time, the left space of the oil cylinder is communicated with the low-pressure oil circuit through the oil hole, and the oil in it is discharged. Under the action of the pressure difference, the servo piston drives the fuel injection pump rack to move left to reduce the fuel supply. When the speed returns to the original value, the spool valve also returns to the central position, and the adjustment process ends.
When the load increases and the speed decreases, the speed regulation process proceeds in the opposite direction.
It can be seen from the above analysis that the centrifugal force generated by the fly ball of the governor is only used to push the spool valve, so the weight and size of the fly ball can be made smaller. As for the force of the hydraulic servo as an amplifier, the servo pistons of different sizes and different lubricating oil pressures can be selected to amplify according to the needs.
However, in this type of governor, since the sensing element directly drives the spool valve, no matter which direction it moves, it is difficult to accurately return to the original position to close the oil hole. This makes the speed of the diesel engine unstable, resulting in serious fluctuations.
In order to make the governor adjust stably, a device should be added to the governor. Its function is to have a reaction on the spool valve when the servo piston moves, so that it moves to the balanced position and reduces the speed fluctuation of the diesel engine. possibility. Such a device is called a feedback mechanism.