Automotive computer sensors

Most automotive computer sensors are of the variable resistor type as in the resistance will change the reference voltage heading back to the power train control module (PCM).

Some of the most interesting automotive sensors are the ones that produce their own voltages.

Some of the most popular components that generate their own voltage would include the Hall effect switch, oxygen sensors, knock sensors and magnetic pulse generators such as a speed sensor.

All of the above, car parts are capable of producing their own voltage signal. This is usually a varying voltage signal that when received by the computer enables it to monitor and adjust for changes in the engine fuel and spark control systems.

Permanent magnet generators

They are also called PM generators. These sensors are often used to send data to the control module to indicate the speed of individual components.

These voltage producing automotive computer sensors are used in several different critical areas of vehicle operation. Not only do these parts increase fuel economy, reduce engine emissions but also improve driver safety.

A magnetic speed sensor is also used to provide important information to the computer about the exact position of a monitored device.

This is common in engine controls where the powertrain module needs to know the position of the crankshaft in relation of other rotational components.

Types of automotive computer sensors

The pickup coil was used in automotive technology for the span of about 15 or 20 years. When this component fails, it can cause a no start condition or if it fails intermittently can cause misfires and lack of power. But how does a pickup coil work.

The pickup coil is known as a stator automotive computer sensor, and sometimes is nicknamed the pole piece. A pickup coil consists of a permanent magnet with fine wire wrapped around it.

There is a small air gap between the pickup coil and the timing disk. The amount of this air gap is critical to correct operation and can be reduced by metal fillings attracted to the magnets.

As the timing disk rotates in front of the pickup coil or pole peace, the generator sends a pulse signal to the ignition module. This is produced as a tooth on the timing disk aligns with the core of the pickup coil. it then repels this generated magnetic field.

This action is repeated every time a tooth passes the pole. The moving lines of magnetic force cut across the coil windings and induce a voltage signal.

To simplify this basically when a tooth approaches the pole piece a positive current is produced as the magnetic field begins to concentrate around the coil.

When the tooth and core an in line there is no more expansion or contraction of this magnetic field and the voltage drops to zero. When the tooth passes on the opposite side of the pole piece a negative current is produced.

Using these three measurements of positive voltage, zero voltage, and negative voltage, extremely accurate position reporting is accomplished.

Testing of these automotive computer sensors can be performed with a scan tool or even a automotive meter.


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