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Automotive sensor information collected from from Wikipedia

Water in Fuel Sensor

WiF sensor indicates the presence of water in the fuel. It is installed in the fuel filter and when the water level in the water separator reaches the warning level, the Wif sends an electrical signal to the ECU or to dashboard The WiF is used especially in the Common Rail engines to avoid the Fuel injector damage.

The WiF sensor uses the difference of electric conductivity of water compared to diesel and gasoline to determine the presence of water. The WiF sensor can consist of two electrodes that reads the level of resistance in the fluid or between the ground and the electrode

Mass Air Flow Sensor

A mass (air) flow sensor (MAF) is a sensor used to determine the mass flow rate of air entering a fuel-injected internal combustion engine.

The air mass information is necessary for the engine control unit (ECU) to balance and deliver the correct fuel mass to the engine. Air changes its density with temperature and pressure. In automotive applications, air density varies with the ambient temperature, altitude and the use of forced induction, which means that mass flow sensors are more appropriate than volumetric flow sensors for determining the quantity of intake air in each cylinder.


There are two common types of mass airflow sensors in use on automotive engines. These are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with additional sensors and inputs, an engine's ECU can determine the mass flow rate of intake air.

Crankshaft position sensor

A crank sensor is an electronic device used in an internal combustion engine, both petrol and diesel, to monitor the position or rotational speed of the crankshaft. This information is used by engine management systems to control the fuel injection or the ignition system timing and other engine parameters. Before electronic crank sensors were available, the distributor would have to be manually adjusted to a timing mark on petrol engines.


The crank sensor can be used in combination with a similar camshaft position sensor to monitor the relationship between the pistons and valves in the engine, which is particularly important in engines with variable valve timing. This method is also used to "synchronise" a four stroke engine upon starting, allowing the management system to know when to inject the fuel. It is also commonly used as the primary source for the measurement of engine speed in revolutions per minute.

Crash sensor

A crash sensor, or impact sensor, is used in motor vehicles to detect a collision of the vehicle against an obstacle.

Once the sensor has detected a collision, it sends an electrical impulse to various control units, which in turn activate various occupant protection systems. Depending on the vehicle equipment, these include airbags, belt force limiters, belt tensioners and roll bars. Some vehicle types also initiate the unlocking of the vehicle doors. The activation of the crash sensor is recorded in the accident data memory.

Older crash sensors only detect a collision per se and activate the occupant protection systems as soon as a predefined threshold value for vehicle deceleration is exceeded. Modern, so-called intelligent sensors, on the other hand, can also detect the severity of an impact and activate different occupant protection systems depending on this, which can reduce the risk of airbag-induced injuries to the vehicle occupants.

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