The air intake system supplies the engine with the combustion air required for operation. This ensures good power output and low exhaust emissions. Find out now everything interesting about the engine air intake system, which components it contains and how to replace components yourself.

Function and structure of the air intake system

The air intake system directs the air necessary for combustion into the engine and regulates the air flow. In addition, the system provides certain measured values for the engine control system. The special design of modern air intake systems ensures a high air flow rate and a powerful intake noise.

The various components of the air intake system

The air intake system of the internal combustion engine is made up of various components. The various components of the air intake system clean the intake air and feed it to the combustion engine. Each component has its own special function.

Air filter

The air filter filters the air drawn in by the engine. This is important, as otherwise sucked-in dirt particles could quickly cause damage inside the engine. The filter itself consists of fine-pored paper, foam or a suitable filter fleece. In the intake system, the air filter represents one of the first elements of the air supply to the engine.

Air filter box

Modern vehicles often have an air filter box. This is a closed box made of plastic that holds the air filter. The air filter box has an inlet for the intake of outside air and an outlet from which the cleaned air flows. Thus, the engine receives cooler ambient air instead of warm air from the engine compartment.

Mass air flow meter

The air mass meter or air mass sensor measures the mass of air entering the intake system. The recorded data is passed on to the engine control system. Modern mass airflow sensors also measure the prevailing pressure and temperature of the air. Thanks to the measured values, the amount of fuel to be injected can be determined precisely.

Air flow meter

Older cars in particular have an air flow meter instead of a mass air flow sensor. This is a compact component with a pivoting air flap inside. The angle of the flap changes depending on the air flow rate. The flap position is measured by a rotary potentiometer and passed on to the engine control unit.

Throttle valve

The throttle valve determines how much air flows into the engine. For this purpose, the component has a rotatable flap inside, which can be used to throttle the air flow. In gasoline engines, the throttle valve is located in the carburetor or in a separate housing in front of the intake manifold. Some diesel engines also have this component for throttling the air flow.

Raw air tube

The raw air tube draws in unfiltered air and feeds it to the air filter or air filter box. In modern vehicles, the raw air tube is often integrated into the front of the vehicle, for example behind the radiator grille. This allows cooler air outside the engine compartment to be drawn in unhindered via the air tube and fed into the air system.

Intercooler

An intercooler is found in the intake system of many vehicles with turbocharged engines. Here, the cooler ensures that the air flow is cooled before it enters the engine. The component is positioned in the air intake system behind the turbocharger and in front of the throttle valve. The cooler air results in better efficiency and higher engine output in turbocharged engines.

Turbo hose

The turbo hose or turbo charge air hose connects individual components upstream or downstream of the turbocharger. As part of the air system, it supplies fresh air to the turbocharger from the direction of the air filter, depending on its position. Behind the turbo, a turbo hose conveys the compressed air. The lines in front of or behind the intercooler are also called turbo hose.

Repairs and spare parts for the air intake system

Proper functioning of all components of the air intake system is important for the car’s internal combustion engine to work as intended. If a component in the air intake system is defective, it should be promptly replaced with a suitable spare part. Spare parts for the engine air intake system are readily available second-hand in good condition. The replacement of the components is usually uncomplicated.

Replacing the air filter

The air filter in a car becomes dirty with increasing mileage and should be replaced at regular intervals. In addition, depending on the material used, the filter is subject to natural aging. Replacing it is not difficult and can be done in just a few steps.

1. Open the air filter box: To remove the air filter, lift the hood to access the air filter box. To remove the old air filter, the housing must be opened. This works in different ways depending on the vehicle model.
2. Removing the air filter: After opening the air filter box, the air filter can be easily removed by hand. The filter material should then be checked for dirt. In most cases, replacement is necessary, which must be done with a suitable replacement filter.
3. Insert the new filter: The new air filter is inserted into the air filter box in place of the old air filter. Before doing so, the box and the feed should be checked for dirt. Once the air filter has been inserted correctly, the filter box is closed again.

Cleaning the throttle valve

Proper functioning of the throttle valve is important for the engine to operate optimally and reliably. However, the butterfly valve often becomes dirty over time, which occurs especially in engines with exhaust gas recirculation. The throttle valve must then be cleaned.

1. Removing the throttle valve: The best way to clean the throttle valve is to remove the component first. To do this, the connectors on the throttle body must be removed and the screw connections loosened. The component can then be removed.
2. Cleaning the component: The throttle body is often contaminated with stubborn particles. A special throttle body cleaner can be used to clean the throttle body. The cleaner is sprayed into the throttle body and the dirt is removed with a soft cloth.
3. Installing the throttle valve: After cleaning, the throttle valve is reinstalled and connected in reverse order. If the dirt proves to be stubborn or the component is damaged, a suitable replacement part should be installed instead.

Replacing the intercooler

The intercooler ensures that the combustion air behind the turbocharger is cooled. The radiator itself is often cooled by air and is attached to the front of the vehicle for this purpose. Here, the intercooler is sometimes damaged and must be replaced.

1. Removing the intercooler: To remove the defective intercooler, the underbody paneling or bumper and radiator grille must be removed, depending on the vehicle model. The air hoses and screw connections of the radiator can then be loosened.
2. Check the intercooler: After removing the charge air cooler, it should be visually inspected for damage. Often, the damage is easy to detect and repair is out of the question. A new or good used cooler is often readily available.
3. Installing the air cooler: Before installing the replacement part, it should be compared with the old intercooler. If the dimensions and design are correct, the replacement cooler is installed in reverse order. This is followed by the assembly of the previously removed body parts.