NTK explains the main differences between inductive and Hall speed sensors

The brand also offers guidance to ensure accurate measurement, regardless of the type of sensor used

São Paulo, October 2024- Rotation sensors, fundamental for the efficient operation of modern engines, are responsible for monitoring the speed and position of the engine's internal components, Like the crankshaft, Engine crankshaft, Providing critical data to the electronic management system. Two main types dominate the market: inductive sensors and Hall sensors. The NKT, brand of Niterra, Japanese multinational that also owns the NGK brand and specializes in components for ignition systems, explains the difference between these types of sensors and their applications.

1- Inductive Sensors: composed of a coil and a permanent magnet, These sensors generate a sinusoidal signal from the proximity variation of the sprocket coupled to the crankshaft. As the sprocket rotates, it moves closer and away from the sensor, Creating a voltage variation. A deliberate failure in one of the teeth of the sprocket indicates the positioning of the Upper Dead Center (PMS) of the first cylinder. Visually, These sensors are characterized by the magnet and the connector that requires fewer wires, normalmente 2 fios um sinal e outro negativo. A amplitude do sinal varia de acordo com a rotação e o tipo de bobina.

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2- Hall Sensors: use an electronic circuit powered by the engine's electronic management system, being able to generate a square wave signal. The toothed crown, in this case, is magnetized, and the signal amplitude depends on the supply voltage, geralmente de 5 ou 12 volts. They have connectors with more wires, A sign, Positive and negative food, as they need constant food. These sensors stand out for their accuracy and reliability, being widely used in modern engines.

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Accuracy of Rotation Sensors

The accuracy of a rotation sensor can be compromised by a number of factors, many of which are not directly related to the sensor itself. Among the most common problems are crankshaft clearances, both radial and axial, The warping of the crankshaft tip, Gaps in the ring ring or keyway, the incorrect distance from the sensor, lack of power supply, Buildup of debris on the sensor (especially when it is located near the flywheel) and the breakage of teeth in the flywheel.

"To ensure reliable measurement, It is essential that mechanics verify the signal generated by the sensor using an oscilloscope or other appropriate measuring equipment.", afirma Hiromori Mori, Niterra Technical Assistance Consultant. "This ensures that the signal is within the correct standards and avoids incorrect diagnoses, when the sensor is generating a signal and the injection module does not receive it, It is important to check the continuity of the wiring harness (electric circuit) and signal input into the injection module. ”