Air Mass Meter
Air mass meters also known as "air flow meters" – are used for measuring the amount (or mass) of air that flows into the engine of an automobile. This information of the amount (or mass) of air is then used for calculating the correct volume of fuel that is needed by the engine. Needless to say, without an air mass meter, motorists can never be certain about the volume of fuel that they need to keep the engine of their vehicle running smoothly.
In most cases, the air mass meter is located right behind the airbox. This location helps the air mass meter to measure the volume of filtered air. The air mass meter is basically a tube made of plastic. Through this tube, air passes into the engine of the vehicle. However, the tube is equipped with a number of sensors that are located on the insides. There is even a plug which, in turn, is connected to a number of electric wires. The sensors, together with the air mass meter, send out the data related to the amount (or mass) of air to the computer of the car – that is, to the ECU.
Over time, the air mass meter may come across a number of problems. For instance, the air that flows through it may be responsible for reducing its overall efficiency. This is surprising since most people know that only filtered air pass through the air mass meter. However, even though the air has been filtered – with the help of the panel filter located inside the air box, the air may still be somewhat contaminated. In most cases, the air contains a significant amount of extremely tiny pollens and dust particles, while other types of particles may also be present.
So, when this contaminated air continuously flows into the vehicle engine through the meter, the dust particles get accumulated in the air mass meter. Over a span of months, the amount of dust particles that are in the air mass meter is too high. This results in a loss of efficiency of the air mass meter. If the dust particles continue to accumulate in the air mass meter, the air mass meter will soon go out of function. If this happens, this will detrimental for the whole car since, without the air mass meter, the motorist will not know about the correct volume of fuel that is needed. As a result, people need to replace the air mass meter with a new one in order to stop causing harm to their engine. In fact, replacement is a much better option than cleaning the inner parts of the air mass meter.
The air mass meter is mostly of two types: the hot wire and the vane meter. Both of these are known for using extra sensors in order to give the most accurate measurement of the rate of air flow into the engine.
In the hot wire sensor an electric current passes through the wire, raising its temperature. As the temperature continues to rise, the resistance of the wire also changes – resulting in a change in the flow of electric current through the wire. When air flows through the wire, the air provides a cooling effect, which, in turn, lowers the electric resistance of the wire. As a result, more current is able to pass through it. This shows that the current and the volume of air through the wire are directly proportional.
In the vane meter sensor, there is a vane which located in the passage of the air flow. As a result, whenever, air passes through, the vane changes its position, generating a voltage. This voltage is proportional to the movement of the vane, and hence the amount of air flow. Two of the most popular air mass meters are Pierburg air mass meter and Bosch air mass meter. Both of these are used for VW, Seat and Audi diesel engines.
In most cases, the air meter is capable of producing a voltage of 0 to 5 V. The air mass meter requires data output from many sensors; as a result, its measurements may not be very accurate. This limitation faced by air mass meters can be avoided with the use of an EGO (exhaust gas oxygen) sensor.
