Basic Starting System

Summary

This video delves into the intricacies of a car's starting system, detailing its components like the battery, ignition switch, neutral safety switch, starter relay, and battery cables. It explains the role of the starter motor, which is a powerful electric motor that initiates engine rotation, enabling the spark and fuel injection systems to operate. The video also covers the working principles behind the starting system, including the functions of the ignition switch, the importance of the neutral safety switch, and how the starter relay manages high electrical current. Additionally, it discusses the starter motor's operation, including the use of an overrunning clutch to prevent damage once the engine starts.

Takeaways

• 🔋 The starting system's primary components include the battery, ignition switch, neutral safety switch, starter relay, battery cables, and starter motor.
• ⚙️ The starter motor is a powerful electric motor designed to rotate the engine, initiating the spark and fuel injection systems to start the engine.
• 🔌 The automotive battery, typically a lead-acid storage battery, supplies the necessary current to the starter motor and other electrical systems in the vehicle.
• 🔑 The ignition switch has multiple positions, including lock, accessory, run, and start, each controlling the flow of electrical current to different parts of the vehicle.
• 🛑 The neutral safety switch prevents the starter from engaging if the transmission is not in neutral or park, ensuring safety during starting.
• 🔄 The starter relay is used to control a large amount of current with a small electrical signal, protecting the ignition switch from the high currents required to start the engine.
• 🔌 Battery cables are large, multi-stranded wires that carry the high current from the battery to the starter motor.
• 🏎️ The starter motor's pinion gear meshes with the engine's flywheel gear to turn the engine over, initiating combustion once the engine speed increases.
• ⚙️ The Bendix gear in the starter motor disengages the pinion from the flywheel gear once the engine starts to prevent damage from over-speeding.
• 🔧 There are two types of starter systems discussed: inertia and pre-engaged, each with its method of engaging and disengaging the starter motor's pinion gear.

Q & A

What is the primary function of the starter motor in a vehicle's starting system?

The starter motor is an electric motor that rotates the engine to allow the spark and fuel injection systems to initiate the engine's operation under its own power.

Where is the starter motor typically mounted in a vehicle?

The starter is generally mounted to the bottom, typically to one side of the vehicle's transmission bell housing, where it connects to the engine itself.

What is the role of the automotive battery in the starting system?

The automotive battery supplies current to the starter motor, provides current to the ignition system while cranking, supplies additional current when demand exceeds the alternator's supply, and acts as an electrical reservoir.

How does the ignition switch distribute electrical current in a vehicle?

The ignition switch allows the driver to distribute electrical current to where it is needed, with five key positions: lock, off, accessory, run, and start.

What is the purpose of the neutral safety switch in the starting system?

The neutral safety switch opens to deny current to the starter circuit when the transmission is in any gear but neutral or Park, ensuring the starter will not engage unless the vehicle is in park or the clutch pedal is depressed.

How does a starter relay help in controlling the large amount of current needed to start an engine?

A starter relay allows a small amount of electrical current to control a large amount of current. It is installed in series between the battery and the starter to manage the high current required to start the engine without overloading the ignition switch and wiring.

What are the functions of battery cables in the starting system?

Battery cables are large diameter, multi-stranded wires that carry the high current necessary to operate the starter motor. They connect the battery to the starter, ensuring the flow of current required to start the engine.

How does the starter motor engage with the engine to start it?

The starter motor has a small gear pinion attached to its end. When activated, this gear meshes with a larger gear ring attached to the engine, spinning the engine over so that the piston can draw in a fuel/air mixture to start the engine.

What is the purpose of the Bendix gear in the starter motor?

The Bendix gear is a device that engages the starter motor's pinion with the gear ring on the flywheel only while the starter is turning the engine. It disengages as soon as the engine picks up speed, preventing the starter motor from being damaged by overspeeding.

How does the starter motor prevent damage from overspeeding once the engine starts?

The starter motor is equipped with a freewheel clutch, similar to a bicycle's freewheel, which disengages the starter gear from the engine gear once the engine starts and begins to spin faster than the starter motor.