What Role does the Solenoid Play

What is the Working Principle of a Solenoid Valve?

When running properly, the internal combustion engine continues to run in a continuous process of inertia of the engine's moving parts as long as it has a fuel supply. However, starting the engine is a separate process in order to make the inertia move in the first place. This is the work of the starting system, whose main components include the following two points.

Start Battery, Motor, Solenoid Switch

The process has not one, but two separate currents, a stronger current and a weaker current. When activated, usually by turning the key in the ignition switch, the weaker current passes through the switch and the solenoid. At this point, the current forces the two large contacts together in the solenoid, which allows a stronger current to pass through the contacts of the solenoid. The current carried by these contacts needs to come directly from the heavy wiring of the battery. This current is heavy enough that it would be unwise to send it through the manual switching mechanism. Therefore, a weaker current through the ignition switch is required.

The stronger current is passed to the starter motor, where it initiates two separate actions. The starter motor is designed so that the current activates a lever that forces the pinion to extend the spring-loaded shaft outward. When extended, this gear, called the pinion, makes contact with a gear on the outer edge of the large flywheel at the end of the engine drive shaft. This large gear is called the starter gear ring.

Start Engine

The second action in a DC motor is the rotation of its central shaft, which is caused by the higher current through the motor. The motor converts the electrical energy into mechanical energy for the rotation of the central shaft. This is done because the current interacts with the magnetic field in the starter motor and causes the rotor on the shaft to start rotating. When this rotation action reaches the maximum speed for which the motor is designed, the pinion at the end of the shaft has engaged the ring of teeth on the flywheel. The engine then starts to run on its own and the safety function of the starter automatically disengages the pinion from the ring. The spring brings the pinion safely back to its resting position and completes the starter mechanism.

When starting, problems can be encountered if the ignition key is held in the "start" position for a little too long. There is also a spring here that will return from the "start" switch to the "on" position once the key is released. If you don't do this, you'll soon hear evidence of the error. The good news is that your mistake is not as bad as it sounds. The safety mechanism in the starter has released the pinion from the gear ring. The bad news is that if you do this often or for long periods of time, you may shorten the life of your starter motor considerably.

A solenoid solenoid is an electromechanical actuator with a magnetic core called a piston that moves freely within the solenoid. Typically, a solenoid consists of a spiral coil and a moving core piston made of iron.

Current Detection

When an electric current passes through the solenoid coil, a magnetic field is generated inside the solenoid. This magnetic field creates a force that pulls the piston in. When the magnetic field generates enough force to pull the piston in, the piston moves inside the solenoid until it reaches the mechanical stop position. Once the piston has moved into the solenoid valve, the magnetic field only needs to generate the force that holds the piston in place. When the current in the solenoid valve coil disappears, the piston will return to its original position, pushed by the spring in the solenoid valve.

The solenoid is a linear motor with a fixed range of operation. Solenoids are suitable for simple switching applications and act much like relays. For example, they serve this purpose in starters and door locks. Solenoids are available in numerous adaptable brands, such as trombetta solenoid, Cummins solenoids, etc.

On the other hand, linear or proportional solenoids can be controlled in a very precise manner. They are used in applications such as transmissions and fuel injection to operate pistons or valves in order to accurately control fluid pressure or flow.

Transmissions require accurate and smooth control of pressure on the clutch to change the transmission, and are used to control a latching torque converter. Electronically controlled transmissions may include more than eight linear solenoids, all of which need to be controlled smoothly and accurately. For common rail diesel fuel injection applications, with pressures in excess of 2000 psi (pounds per square foot), a linear solenoid may be required for each cylinder and a solenoid is required for the fuel pump to accurately adjust the pressure and ensure that the fuel flow is injected in the intended manner.