A spool valve is used in practically every business you can think of to do a variety of duties, but what exactly is one and how does it operate?
Spool valves are used to control the flow direction of the energy source by combining or switching the routes through which the oil or air can go in hydraulics and pneumatics, respectively, where the energy source is oil and the energy source is air.
The case has many chambers that are bored through it from one side to the other; these are called “ports.”
As it moves inside the sealed box, the spool serves the purpose of either blocking or opening these ports, depending on its position.
In This Article...
What does a transmission’s spool valve do?
The valve body is the main component of the hydraulic control system for automatic transmissions. The separator plate or transfer plate, the valves, and the actual valve body make up this component. The top and lower sections are separated by a separator plate and a gasket. It can be made of iron or, for the majority of transmissions, aluminum, and is fitted onto the transmission as a single piece.
The poppet, check ball, and spool valves are among the several valves that make up the valve body.
A flat disc or a ball might serve as the poppet valve. It typically features a stem that serves as a guide for opening and shutting the valve. This valve functions as a port; it either prevents or permits fluid passage.
The valve body has a seat for a check ball valve. Depending on the flow direction, it either permits or prohibits fluid flow. Depending on the use and manufacturer, they are either typically open or closed.
The most typical valve seen in automatic transmissions is the spool valve. With broad sections meant to obstruct fluid movement called lands and stemmed portions called valleys, they resemble a spool of thread. A reaction area is located at each end of the valve. It is the region where the valve is activated by a force generated by fluid pressure, a linkage, or a spring.
What function does the VTEC solenoid spool valve serve?
Given that Honda’s variable valve timing system is known by its fancy moniker, VTEC, it serves the purpose of advancing the timing when more power is required for the higher rev range.
The VTEC solenoid’s job is to regulate the oil supply to the overhead camshaft’s internal galleries.
The oil pressure switch and Honda’s VTEC solenoid cooperate to turn on the high-performance setting of the camshaft.
Given the age of many Honda vehicles using the beloved VTEC technology, oil pressure problems could develop over time for a number of different causes.
Despite the VTEC system’s reputation for dependability, it’s likely that you’ll need to replace your solenoid at some point. Fortunately, it can be far less expensive than it sounds, so don’t panic.
What results in a spool valve failing?
Sliding spool/bore valves are the most common type of DCV valve. When a valve sticks, typical force applied by the operator will not cause the spool to move. This sticking action can be brought on by a number of things, such as pollution, silting, mechanical failure, or operator error. Let’s examine these typical causes.
The usual amount of force needed to move the spool increases beyond the operator’s capabilities when hard particle contamination occurs between the bore and the spool. As soon as the contamination is removed, the spool becomes stuck and cannot be moved. The bore and spool will be harmed by forcing the spool to move, leading to wear and gouges. This creates a circle of contamination that damages the valve more and more until it starts to leak excessively. The most effective technique to stop the sticking action is to disassemble the valve and remove the contaminants before it does more harm.
In contrast to hard contamination like sludge and varnish, silting typically involves soft contamination. The operator cannot create enough force to move the spool past the silt in the hydrostatic lands and bores because silting increases the sliding force required to move the spool. The easiest technique to stop a silting activity is to disassemble the valve and thoroughly clean every component.
A DCV contains a lot of tiny, fragile parts, many of which are prone to breaking. A broken spring, pin, washer, or detent device might jam or stick the valve. It will be necessary to replace the damaged components or the valve entirely.
The DCV changes position in response to an external stimulus of some kind. Electrical (solenoids), hydraulic (pistons), mechanical (levers and rods), and pneumatic operators are the most prevalent types (pistons). The first thing to determine is whether the operator is sticking the DCV or if a problem with the hydraulic element of the DCV is to blame. To allow the mechanic to manually manipulate the valve, the majority of valve operators feature a tiny mechanical component called a manual override. If the valve shifts with the manual override but not with the usual signal, there is probably a problem with the operator. When using the manual override, if the valve won’t shift, there’s probably a hydraulic or mechanical issue with the DCV. The solenoid coil burn out that can result from a failure of the hydraulic portion of the valve must be fixed when the DCV is disassembled and rebuilt.
How is a spool valve adjusted?
You might need to change the spool valve if the hydraulic fluid pressure is too low or excessive, which will save your business time and money. You can safely set the valves to the factory-preset pressure and pressure range. To prevent harming the valve and decreasing its effectiveness, stay within this range.
Pressure can be calculated with the aid of flow rate. Manufacturers set the spool valve pressure at a standard rate of 10 gallons per minute. To compensate for the higher pressure caused by the increased fluid flow, reduce the valve’s pressure for higher flow rates. In contrast, low flow results in low pressure; to make up for this, pressure is increased.
Leasing the valve-locking nut on the side will let you to adjust the spool valve. You may access the adjustment screw by removing the locking nut. To increase pressure, turn the screw in a clockwise direction; to decrease pressure, turn it in a counterclockwise direction. Before replacing the locking nut and reinstalling the spool valve, use a pressure gauge to be sure you’ve created the proper pressure adjustment.
If the spool valve has been correctly set and the issue persists, you might need to try checking the hydraulic system’s valves. There are often just three basic problems with these hydraulic parts. However, just because there aren’t many issues doesn’t mean troubleshooting will be simple.
Which two spool valve types are there?
A sliding spool-type directional control valve with four ways, two positions, a spring return, and manual lever operation is depicted in the image below.
The flow routes PB and AT start when the device is in its default position (the unactuated position).
- The two-position valve is most frequently used in cylinder applications where the cylinder only needs to expand or retract to its greatest positions.
- Hydraulic motors, which can only move in one direction forward or backward, would be another application.
Why is there a 2 spool valve?
Meaning of “2 spool valve”
Valve Body Features:
- Rated Flow: 25 GPM
- P = 5080 PSI, T = 3050 PSI, A & B = 5080 PSI are the maximum operating pressures.
- Outlet (Tank) Port: #16 SAE (1 5/16 -12 ORB) female thread
- Female thread #12 SAE (1 11612 ORB) Inlet (Pressure) Port
- 3000 PSI Capable
- Work Ports with a #12 SAE (1 11612 ORB) female thread
- Body in aluminum
- a sturdy aluminum enclosure constructed for use
A solenoid spool valve: what is it?
A machined spool that moves inside a machined valve body makes up spool solenoid valves. A plunger acts on one or both ends of the spool and, when actuated by either coil, pushes the spool in one of three possible directions.
Why does the solenoid on my VTEC keep failing?
Hello, and thank you for your letter. The fact that the solenoid keeps breaking down could mean that the mechanical or electrical components behind it are malfunctioning. To begin diagnostics, there are two options. First, remove the assembly to which the solenoid is connected and look for deposits while keeping in mind the interaction with engine oil. These assemblies have the potential to clog and harm the solenoid. If necessary, you can swap out the assembly or clean it. If everything about the assembly is good, you should go on to electrical testing. To determine whether the solenoid is receiving too much or too little power would be the objective. Make an appointment with our service department to receive additional assistance.
How can I fix the issue with my VTEC system?
The most frequent reason for error code P1259 or VTEC system failure is low oil pressure. Therefore, be sure to check your oil if it has to be serviced. Replace the oil and filter as necessary. Before trying them, clear the codes.
How is a spool valve tested?
Install a flow meter and a pressure gauge in the drain/tank port line to check this. Differential pressure is the basis of all hydraulic systems. The actuation pressure must first overcome any excessive back pressure in order to move the spool. Most systems only need a little amount of back/drain pressure to run efficiently.
What are the solenoid’s top 5 common issues?
Despite the fact that solenoids come in a wide variety of sorts, there are a few fundamental categories into which these issues can be divided. Plungers that are jammed in or out, attached valves that are locked in place, damaged internal coil windings, and excessive noise while operating are all common solenoid issues. While some of these difficulties are often caused by exterior components, others are the result of internal solenoid troubles. Different solenoid issues require different approaches to repair since while some solenoids can be repaired, others simply need to be replaced.
Electromechanical devices called solenoids are frequently employed to control the flow of different substances. An iron or steel armature and a helical coil make up the basic building blocks of a solenoid. The solenoid can predictably transform electric power into mechanical energy when it is applied. Solenoids are frequently used in conjunction with valves to control whether or not a signal from an electrical source has been applied. In other circumstances, solenoids can be employed to carry out additional mechanical tasks, including closing a group of contacts.
Many typical solenoid issues are related to this system because solenoids rely on inductive coils to function. A solenoid may stop functioning properly due to faulty internal windings, and coils may melt, burn, or simply short circuit. If the armature is bent or dirty, if there is too much heat or moisture present, or if the wrong voltage is given to a device, similar problems may develop.