The Kettering ignition system, also known as the conventional ignition system, was a pioneering technology that revolutionized the way internal combustion engines were started and operated. Developed by Charles F. Kettering in the early 20th century, this ignition system played a significant role in the advancement of automotive engineering. In this article, we will explore the Kettering Type Ignition System, its components, operation, and its impact on the automotive industry.

Components of the Kettering Type Ignition System:

1. Battery: The battery provides the initial electrical energy needed to power the ignition system. It supplies low-voltage current (usually 12 volts) to the primary circuit of the ignition coil.
2. Ignition Switch: The ignition switch is turned on by the driver to provide power to the ignition system. When the switch is turned to the “On” position, it allows current to flow from the battery to the ignition coil.
3. Ignition Coil: The ignition coil is a transformer that converts the low-voltage current from the battery into a high-voltage output. It consists of primary and secondary windings. The primary winding is connected to the battery, and the secondary winding generates the high-voltage spark.
4. Distributor: The distributor is a mechanical device with a rotating rotor inside. It’s responsible for routing the high-voltage spark from the ignition coil to the correct spark plug at the precise moment for combustion. The distributor also houses the breaker points or ignition points.
5. Breaker Points (Ignition Points): These are mechanical contacts within the distributor that open and close as the distributor rotor spins. The opening and closing of the points interrupt the flow of current in the primary circuit of the ignition coil. This interruption creates the rapid on-off cycling required to induce a high-voltage output in the secondary winding.
6. Condenser (Capacitor): The condenser is connected in parallel with the breaker points. It prevents arcing at the points when they open, which can cause excessive wear and reduce the efficiency of the ignition system.
7. Distributor Cap: The distributor cap covers the top of the distributor and has terminals for each spark plug wire. It provides electrical insulation and guides the high-voltage spark from the rotor to the appropriate spark plug wire.
8. Rotor: The rotor is mounted on the distributor shaft and rotates as the engine runs. It distributes the high-voltage spark from the ignition coil to the spark plug terminals within the distributor cap.
9. Spark Plug Wires: These wires carry the high-voltage spark from the distributor cap to the individual spark plugs in the engine’s cylinders. They are insulated to prevent electrical interference and arcing.
10. Spark Plugs: Spark plugs receive the high-voltage spark from the spark plug wires. The spark jumps the gap between the center and ground electrodes of the spark plug, igniting the air-fuel mixture in the combustion chamber.

Operation of the Kettering Type Ignition System:

The operation of the Kettering Type Ignition System can be summarized in the following steps:

1. Battery Power Supply: When the driver turns the ignition key to the “On” position, electrical power from the car’s battery is supplied to the ignition system. The battery’s low-voltage current (typically around 12 volts) energizes the primary circuit of the ignition coil.
2. Primary Circuit Activation: The ignition coil consists of primary and secondary windings. The primary winding is connected to the battery power supply, and the secondary winding is connected to the spark plugs. When the primary circuit is energized, a magnetic field is created around the coil.
3. Breaker Points Closure: Inside the distributor, a set of breaker points (or ignition points) is mounted. These points are mechanical contacts that are held together by a spring. As the engine’s camshaft rotates, it causes a cam to open and close the breaker points at specific intervals. When the points are closed, the primary circuit of the ignition coil is completed, allowing current to flow through the coil.
4. Magnetic Field Buildup: As current flows through the primary winding of the ignition coil, it creates a magnetic field around the coil’s core. This magnetic field intensifies as the current flows and energy accumulates.
5. Breaker Points Opening: As the engine’s camshaft continues to rotate, the cam causes the breaker points to open suddenly. This opening interrupts the flow of current in the primary circuit. The rapid interruption of current causes the magnetic field around the ignition coil to collapse quickly.
6. High-Voltage Induction: The rapid collapse of the magnetic field induces a high-voltage current in the secondary winding of the ignition coil. This high-voltage current can reach tens of thousands of volts due to the transformation ratio between the primary and secondary windings.
7. Rotor Rotation: Mounted on the distributor shaft, the rotor rotates inside the distributor cap. As the rotor spins, it passes by each terminal connected to the spark plug wires.
8. Spark Generation and Distribution: When the rotor aligns with a specific terminal corresponding to a cylinder, the high-voltage current from the secondary winding of the ignition coil jumps from the rotor’s central electrode to the terminal. This generates a high-voltage spark at the spark plug wire’s end.
9. Spark Plug Ignition: The high-voltage spark travels through the spark plug wire to the spark plug in the corresponding cylinder. The spark jumps the gap between the spark plug’s center and ground electrodes, igniting the compressed air-fuel mixture within the cylinder.
10. Combustion and Engine Operation: The ignited air-fuel mixture undergoes controlled combustion, generating a rapid increase in pressure and temperature. This pressure pushes the engine’s piston downward, converting the chemical energy of combustion into mechanical energy. The mechanical energy turns the engine’s crankshaft, which drives the vehicle’s wheels and propels it forward.

Advantages of the Kettering Type Ignition System:

1. Simplicity: The Kettering Type Ignition System is relatively simple in design and operation, making it easier to understand and maintain.
2. Compatibility: It is compatible with a wide range of engine sizes and configurations, making it suitable for various automotive applications.
3. Durability: The mechanical nature of the breaker points system provides robustness, allowing it to withstand high voltage and current loads.

Disadvantages of the Kettering Type Ignition System:

1. Maintenance: The breaker points require periodic maintenance and adjustment to ensure optimal performance. Over time, the points can wear, leading to degraded ignition efficiency.
2. Limited Control: The Kettering system offers limited control over ignition timing, resulting in less precise combustion optimization.
3. Wear and Deterioration: The mechanical nature of the system makes it prone to wear, corrosion, and degradation, requiring regular inspection and replacement of components.

Conclusion:

The Kettering Type Ignition System played a pivotal role in the advancement of automotive engineering, providing a reliable and effective means of igniting internal combustion engines. While modern ignition systems have surpassed the Kettering system in terms of precision and control, its historical significance cannot be overlooked. The Kettering ignition system paved the way for further innovations, ultimately leading to the development of more advanced ignition technologies that have revolutionized the automotive industry.