Knock Sensor – Working & Its Applications

• “Knocking” occurs on the premature self-ignition of the air-fuel mixture. Repeated knocking causes damage to the cylinder head gasket and cylinder head.

Hazards of Knocking-

• Loud noise (sharp knocking sound).
• Strong knocking reduces the power of the engine,
• The temperature of the engine rises sharply
• Overheating of the cylinder makes the metal soft, melt, or burn.
• The engine is unstable and vibrates violently.

SOLUTION is in DEFINITION

• The Knock sensor identifies the high-frequency engine vibrations (knocking) and transmits a signal to the ECU. The natural aim is to obtain a maximum energy yield by starting ignition as early as possible.

Place of Sensor-

• The knock sensor is mounted on the crankcase(mouth part of cylinder), the knocking is noticeable by its higher sound frequencies. This sound vibration are measured by a piezoelectric measuring element.
• Engines with a knock sensor can reduce fuel consumption and increase torque.
• Piezoelectric measuring element- It senses the variations in pressure-temperature or force and produces electric signals proportionally.

Features of Knock Sensor

• Characteristic curve-Linear over a broad frequency range.
• Temperature range−40 °C to +160 °C.
• Technology-piezoelectric measuring element (ring-shaped piezo ceramic).

Types of Knock Sensor

1. 1. Magnetostrictive Knock Sensor
2. 2 Piezoelectric Knock Sensor
3. 3 Spark plug knock Sensor

Applications of Knock Sensor

• Knock sensors are used in the car’s spark plug.
• Automotive industries.