Hello Everyone and Welcome to This Week's Video: Explaining Mass Airflow Sensors
Today, I'm going to be explaining mass airflow sensors specifically a hot wire mass airflow sensor. Mass air flow sensors are used to determine how much air is going into an engine so that the ECU also knows to tell the fuel injectors how much fuel to inject to keep a good air fuel ratio in the engine.
Mass Air Flow Sensors: What We've Got Going On Inside
So, what we've got going on inside is you've got these little circuits basically and between connected between these wires. We've got these hot wire elements and so we're going to pass a current through these elements and air is going to flow through this. You got a filter basically on the front just so you don't have particles break these wires in there.
What We Want to Keep Going On
Basically, what we want to keep going on is we want to keep this element at a constant temperature and by doing that we can know how much air flow is going into the engine. What happens is say you step on the gas and then you've got more air going into the engine well more air is going to pass through and the current going through this which is heating up this element when that air passes through that air flow up the temperature of this element is going to cool down.
Temperature and Resistance Are Directly Related
Now, temperature and resistance are directly related for this element. So as its temperature drops, its resistance will also drop. Now if we take a look at Ohm's law, Oh's law says that current is equal to the voltage divided by the resistance. If we lower the resistance of this element then we know that this number here is going to be bigger so the current is going to go up now with a larger current that it's going to heat up this element so it's going to bring the temperature back to where it was.
How The ECU Translates This Current Into A Voltage Change
What the ECU does is it translates this current into a voltage change very simple equation. With that voltage change, it knows that there's a difference in air flow now since it knows there's a difference in air flow it can say to send more or less Fuel and in combination with the O2 sensor which I'll explain in a later video it can balance it out and get the perfect amount so they can actually get pretty accurate for the air fuel ratio that that your engine wants to get.
Variation Depending On How Much Throttle You're On
It'll sometimes vary it depending on how much throttle you're on. So, there's other sensors as well which will vary it but one of the most important ones is a mass air flow sensor so that you know how much air is going in your engine.
Location Of A Mass Airflow Sensor On A Car
So if my car were to have a mass airflow sensor it would be located directly behind the airbox. There would be an attachment right here which would be measuring the air coming in instead on my car I've got a uh manifold absolute pressure sensor that's this thing right here so I'll have a future video on that
"WEBVTTKind: captionsLanguage: enhello everyone and welcome to this week's video today I'm going to be explaining mass airf flow sensors uh specifically a hot wire mass airflow sensor now mass air flow sensors are used uh to determine how much air is going into an engine so that the ECU also knows to tell the fuel injectors how much fuel to inject to keep a good air fuel ratio in the engine so mass air flow sensor is going to kind of look like this and it's going to be mounted behind your air filter so I'll show you what this where this would be on a car um on mine my car actually doesn't use this it uses something different but I'll explain that later so mass air flow sensor what we've got going on inside is you've got these little circuits basically and between connected between these wires we've got these hot wire elements and so we're going to pass a current through these elements and air is going to flow through this so you got a filter basically on the front just so you don't have particles break these wires in there uh and basically what we've got going on is we want to keep this element at a constant temperature and by doing that we can know how much air flow is going uh into the engine so what happens is say you step on the gas and then you've got more air going into the engine well more air is going to pass through and the current going through this which is heating up this element when that air passes through that air flow up the temperature of this element is going to cool down now temperature and resistance are directly related for this element so as its temperature drops its resistance will also drop now if we take a look at Ohm's law Oh's law says that current is equal to the voltage divided by the resistance so if we lower the resistance of this element then we know that this number here is going to be bigger so the current is going to go up now with a larger current that it's going to heat up this element so it's going to bring the temperature back to where it was now what the ECU does is it translates this current into a voltage change very simple equation and with that voltage change it knows that there's a difference in air flow now since it knows there's a difference in air flow it can say to send more or less Fuel and in combination with the O2 sensor which I'll explain in a later video it can balance it out and get the perfect amount so they can actually get pretty accurate uh for the air fuel ratio that that your engine wants to get and it'll sometimes vary it depending on how much throttle you're on so there's other sensors as well which will vary it but one of the most important ones is a mass air flow sensor so that you know how much air is going in your engine so we'll take a look at my car real quick and see where this would be located so if my car were to have a mass airflow sensor it would be located directly behind the airbox so there would be an attachment right here which would be measuring the air coming in instead on my car I've got a uh manifold absolute pressure sensor that's this thing right here so I'll have a future video on thathello everyone and welcome to this week's video today I'm going to be explaining mass airf flow sensors uh specifically a hot wire mass airflow sensor now mass air flow sensors are used uh to determine how much air is going into an engine so that the ECU also knows to tell the fuel injectors how much fuel to inject to keep a good air fuel ratio in the engine so mass air flow sensor is going to kind of look like this and it's going to be mounted behind your air filter so I'll show you what this where this would be on a car um on mine my car actually doesn't use this it uses something different but I'll explain that later so mass air flow sensor what we've got going on inside is you've got these little circuits basically and between connected between these wires we've got these hot wire elements and so we're going to pass a current through these elements and air is going to flow through this so you got a filter basically on the front just so you don't have particles break these wires in there uh and basically what we've got going on is we want to keep this element at a constant temperature and by doing that we can know how much air flow is going uh into the engine so what happens is say you step on the gas and then you've got more air going into the engine well more air is going to pass through and the current going through this which is heating up this element when that air passes through that air flow up the temperature of this element is going to cool down now temperature and resistance are directly related for this element so as its temperature drops its resistance will also drop now if we take a look at Ohm's law Oh's law says that current is equal to the voltage divided by the resistance so if we lower the resistance of this element then we know that this number here is going to be bigger so the current is going to go up now with a larger current that it's going to heat up this element so it's going to bring the temperature back to where it was now what the ECU does is it translates this current into a voltage change very simple equation and with that voltage change it knows that there's a difference in air flow now since it knows there's a difference in air flow it can say to send more or less Fuel and in combination with the O2 sensor which I'll explain in a later video it can balance it out and get the perfect amount so they can actually get pretty accurate uh for the air fuel ratio that that your engine wants to get and it'll sometimes vary it depending on how much throttle you're on so there's other sensors as well which will vary it but one of the most important ones is a mass air flow sensor so that you know how much air is going in your engine so we'll take a look at my car real quick and see where this would be located so if my car were to have a mass airflow sensor it would be located directly behind the airbox so there would be an attachment right here which would be measuring the air coming in instead on my car I've got a uh manifold absolute pressure sensor that's this thing right here so I'll have a future video on that\n"