Tip & How-To about Mercedes-Benz E-Class

Air intake by engines

1) Air: From atmosphere to engine
Air enters the engine via the airfilter. The filter should not, ideally, impede air flow but should remove all air-borne particulates. The charge of air taken in should be cold as possible and so the air filter box is best placed where external air can be easily drawn in and where the heating effect of the engine is reduced. Small, after-market, under-hood air filters often have the disadvantage of drawing in hot air from around the engine; and may add to difficulties in restarting hot engines. Air passes from the air filter through an air mass meter in which the volume of air taken in by the engine is calculated by a combination of its temperature and its cooling ability. (MAFand IAT - see later in this series)
Further along the air duct, blow-by gases from the crankcase are added via the PCV to the air stream and this is then drawn past the throttle plate into the intake manifold plenum. At idle the throttle plate is closed and a partial vacuum exists in the manifold. The air pressure is reduced byapproximately a third to about 20 inches (~500mm) of mercury; normal atmosphericpressure is 30 inches (~760mm Hg). This inlet plenum 'vacuum' can be used to operate a number of systems on the car such as central locking, fuel cap release as well as assisting with foot brake servo operation. Furthermore, certain other functions may also make use of the plenum vacuum such as:
Opening the engine's exhaust gas recirculation (EGR) valve;
Operating the intake manifold runner (IMR) valve;
Moderating the fuel pressure regulator (FPR) function; and
Governing 'in-gear duration' (automatic transmission).


NEXT 1b) air intake by engine faults

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Hello there, I have just bought a brand new K&N panel airfilter. When I was driving it its just been cut off 2 times.Any idea why??


Check your mass air flow and see if it's dirty , the new air filter lets more air in and a dirty air sensor will not read the bigger air flow

Jan 22, 2015 | 2000 Volkswagen Lupo

1 Answer

what is the maf senser


Mass Air Flow- the sensor measures the amount of air going into the intake-the only air the engine takes in-so the sensor is mounted in the big air boot between the air filter housing and the throttle body where the air enters to the intake.

The sensor converts the flow data to an electrical signal to the pcm, so it can figure out (with the other engine sensors) how much gas to add with the air for the ideal burn ratio. So it's an important sensor.

Jul 09, 2014 | 2003 Kia Rio

2 Answers

where is the mass airflow sensor on opel zafira 2.2


On the 2.2 zafira, z22se engine. There is no MAF sensor. Which is why you can not find it.
Instead it uses a combination of the IAT (Intake Air Temp) and the MAP (Manifold Air Pressure) sensors.The IAT is the small plastic sensor on the side of the intake duct.The MAP sensor is just after the throttle body. You need to take the whole throttle body off to get at it.

Jul 11, 2012 | Cars & Trucks

1 Answer

My 2005 Sante Fe hesitates and won't get up to speed whenever it is damp or rainy outside. What causes this? Thanks


It could be your MAF (Mass Air Flow) sensor. Do you have any SEL {Service Engine) light coming on?

A mass air flow sensor is used to find out the mass 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 as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the ambient temperature, altitude and use of a turbocharger and this is an ideal application for a mass sensor. (See stoichiometry and ideal gas law.)
There are two common types of mass airflow sensors in usage on automotive engines. These are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engine's air mass flow rate can be accurately determined.
Both approaches are used almost exclusively on electronic fuel injection (EFI) engines. Both sensor designs output a 0.0- 5.0 volt or a pulse-width modulation (PWM) signal that is proportional to the air mass flow rate, and both sensors have an intake air temperature (IAT) sensor incorporated into their housings.
When a MAF is used in conjunction with an oxygen sensor, the engine's air/fuel ratio can be controlled very accurately. The MAF sensor provides the open-loop predicted air flow information (the measured air flow) to the ECU, and the oxygen sensor provides closed-loop feedback in order to make minor corrections to the predicted air mass.

May 27, 2010 | 2006 Hyundai Santa Fe

2 Answers

MAAS AIR SENSOR


A mass air flow sensor is used to find out the mass of air entering a fuel-injected 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 as it expands and contracts with temperature and pressure. In automotive applications, air density varies with the ambient temperature and altitude, and this is an ideal application for a mass sensor. (See stoichiometry and ideal gas law.)
There are two common types of mass airflow sensors in usage on gasoline engines. These are the vane meter and the hot wire. Neither design employs technology that measures air mass directly. However, with an additional sensor or two, the engine's air mass flow rate can be accurately determined.
Both approaches are used almost exclusively on electronic fuel injection (EFI) engines. Both sensor designs output a 0 - 5.0 volt or a PWM signal that is proportional to the air mass flow rate, and both sensors have an intake air temperature (IAT) sensor incorporated into their housings.

Nov 09, 2009 | 1999 Oldsmobile Silhouette

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