Air intake systems provide an engine with the air necessary for combustion. There are several different types of air intake systems, and the type of intake used depends on the vehicle's purpose and function. Automobile air intake systems are tasked with delivering some of the air that flows past the car into the engine itself. The intake is usually just beneath the hood of the vehicle.
The car's intake system has an air filter at one end and is connected to the engine itself at the other by means of a throttle body. Air intake systems are usually tube shaped, varying in length. This design ensures that the air may pass directly to the engine with as little resistance as possible.
The air filter keeps foreign particles out of the intake, where the air itself is measured by a mass airflow sensor. This sensor keeps the fuel to air ratio balanced so that as more air enters the intake more fuel is released into the cylinders to compensate. The throttle body is controlled by the accelerator pedal and is the component within the intake that manages the quantity of air entering the engine.
The majority of non-performance vehicles have a warm air intake. The most basic of air intake systems, it is designed to increase fuel efficiency while giving the driver an adequate amount of power. The air gathered by a warm air intake is warmer than the air outside of the vehicle and thus more excited and less dense, resulting in less oxygen being forced into each cylinder and less fuel being used to burn the oxygen.
Performance automobiles must find a way to gather as much air as possible in order to increase the amount of oxygen being fed into the engine for combustion. These cars will use large quantities of oxygen along with large quantities of fuel to increase their performance, although drastically reducing their fuel efficiency. Performance vehicles employ such constructions as ram-air intakes, cold air intakes, superchargers, and turbochargers to acquire more air.
The ram-air intake relies on the automobile's forward momentum to push more air into it, resulting in more oxygen being forced into the engine and an increase in performance. Placement of the ram-air intake within the engine compartment may affect its performance. The engine can cause the air near it to become heated and less dense, possessing less oxygen per amount consumed. To counteract this effect, installers usually place a heat shield around the filter.
When attempting to gather the most oxygen per amount consumed, many owners will opt for a cold air intake. It gathers the air from a substantial distance away from the engine, where the air is denser, cooler, and as rich in oxygen as possible. Cold air intakes are a simple, relatively cheap modification that can increase an automobile's performance. If set up incorrectly, though, the intake has the potential to cause hydrolock, a situation in which water, instead of air, is pushed into the engine and stalls it. This is a rare occurrence, however.
Forced air induction can be added to an air intake system to further increase airflow. A supercharger, one kind of forced air induction, is active as long as the engine is running and being turned by the engine belt. As the engine achieves greater speeds, the supercharger pushes more and more air into the engine from the intake and acts as an air compressor.
The other option for forced air induction is a turbocharger. Though similar to a supercharger, the turbocharger is driven by the engine's exhaust. As the host gas passes through, the turbocharger spools up, pulling more air into the intake and pushing it into the engine. Each system of forced induction typically increases its intake volume as the engine's rotations per minute (RPMs) increase until it reaches a threshold, at which point the engine's power begins to wane.