(a) Explain, with the aid of a diagram, the operation of a solenoid operated, battery powered electric starting system for an internal combustion engine.(6)
(b) Explain the term pre-engaged starter.(4)
Solenoid Operated, Battery Powered Electric Starting System
A solenoid operated, battery powered electric starting system is the most common method for initiating the combustion process in internal combustion engines.
How it works:
- Battery: Stores electrical energy.
- Ignition Switch: Controls the flow of electricity to the starter solenoid. 1. Starter solenoid – Wikipedia en.wikipedia.org
- Starter Solenoid: An electromagnetic switch that bridges a high-current path between the battery and the starter motor. 1. Starter solenoid – Wikipedia en.wikipedia.org
- Starter Motor: An electric motor that cranks the engine’s flywheel. 1. What is a starter motor and when do you replace it? | RAC Drive www.rac.co.uk
Operation Sequence:
- When the ignition switch is turned to the start position, a small current flows through the solenoid coil. 1. Starter solenoid – Wikipedia en.wikipedia.org
- This energizes the solenoid, pulling a plunger that closes heavy-duty contacts within the solenoid. 1. Starter solenoid – Wikipedia en.wikipedia.org
- The closed contacts connect the battery’s high current output directly to the starter motor. 1. Starter solenoid – Wikipedia en.wikipedia.org
- The starter motor begins to turn, engaging the engine’s flywheel through a starter pinion. 1. Starter solenoid – Wikipedia en.wikipedia.org
- Once the engine starts, the ignition key is released, de-energizing the solenoid and disengaging the starter motor.
Key Components:
- Starter motor: Converts electrical energy into mechanical energy to crank the engine. 1. Electric motor converts: – BYJU’S byjus.com
- Starter pinion: Gears into the engine’s flywheel to initiate rotation.
- Battery: Provides the electrical energy to power the starter motor.
- Ignition switch: Controls the flow of electricity to the starter solenoid. 1. Starter solenoid – Wikipedia en.wikipedia.org
- Starter solenoid: Acts as a relay to connect the battery to the starter motor. 1. Starter solenoid – Wikipedia en.wikipedia.org
This system is efficient, reliable, and widely used in various applications, from small engines to large industrial equipment.
Pre-Engaged Starter
A pre-engaged starter is a type of starter motor where the pinion gear is already in contact with the engine’s flywheel before the starter motor begins to rotate.
This is in contrast to a traditional inertia starter, where the pinion is thrown into engagement with the flywheel as the starter motor spins up to speed.
Key advantages of a pre-engaged starter:
- Reduced wear: As there is no impact between the pinion and the flywheel, it reduces wear on both components.
- Smoother starting: The engine starts more smoothly due to the gradual engagement of the pinion.
- Higher torque capacity: Pre-engaged starters can typically handle higher torque loads.
How it works:
A mechanism is typically in place to disengage the pinion once the engine starts.
The pinion is moved into position and locked in place before the starter motor is activated.
Once engaged, the starter motor begins to rotate, cranking the engine.