Solenoid-Operated Electric Starting System (Internal Combustion Engine)
(a) Operation:
A solenoid-operated, battery-powered electric starting system provides a convenient and reliable way to crank an internal combustion engine for starting purposes. Here’s a breakdown of its operation:
Components:
- Battery: Provides the electrical power for the system.
- Starter Motor: An electric motor with high torque output designed to crank the engine.
- Solenoid: An electromagnet that acts as a heavy-duty relay.
- Ignition Switch: Controls the flow of current to the solenoid.
- Starter Drive Pinion: A gear on the starter motor that meshes with the engine’s flywheel ring gear.
Operation:
- Ignition Switch Turned: When the operator turns the ignition switch to the “start” position, current flows from the battery to the solenoid.
- Solenoid Activation: The current energizes the solenoid’s electromagnet, creating a strong magnetic field.
- Plunger Movement: The magnetic field pulls in a metal plunger within the solenoid.
- Circuit Completion: The movement of the plunger connects two high-current contacts within the solenoid. One contact connects the battery directly to the starter motor, providing full power. The other contact may engage the starter drive pinion with the flywheel ring gear (depending on the system design).
- Engine Cranking: The powerful starter motor begins to spin, cranking the engine flywheel through the engaged drive pinion.
- Engine Starts: Once the engine reaches sufficient speed, the internal combustion process takes over, and the engine continues to run on its own.
- Ignition Switch Released: When the operator releases the ignition switch from the “start” position, the current flow to the solenoid stops.
- Solenoid Reset: The solenoid’s magnetic field collapses, releasing the plunger.
- Circuit Disconnection: The high-current contacts disconnect, stopping the flow of current to the starter motor.
- Drive Pinion Disengagement (if applicable): The starter drive pinion may disengage from the flywheel ring gear (depending on the system design).
Benefits:
- Convenience: Solenoid-operated systems offer a simple and convenient way to start an engine compared to manual crank starting.
- Reliability: Solenoids provide a reliable and consistent means of engaging the starter motor.
- Safety: Ignition switches and interlocks can prevent accidental starter engagement.
(b) Pre-Engaged Starter:
In some starter systems, a pre-engaged design is employed. Here’s what it means:
- Drive Pinion Engagement: The starter drive pinion is already engaged with the flywheel ring gear when the engine is at rest. This engagement can be achieved through a spring-loaded mechanism or a gear arrangement.
- Solenoid Function: The solenoid in a pre-engaged system primarily functions to connect the battery directly to the starter motor for cranking. It may not have a separate mechanism for engaging the drive pinion because it’s already in mesh with the ring gear.
- Benefits: Pre-engaged starters offer faster cranking since there’s no delay for pinion engagement. This can be beneficial in cold weather conditions where easier starting is desired.
Note: Some pre-engaged starters may incorporate a solenoid design that performs both functions – engaging the drive pinion and supplying full power to the starter motor.