Cold air intake on:
[Wikipedia]
[Google]
[Amazon]
A cold air intake (CAI) is usually an aftermarket assembly of parts used to bring relatively cool air into a
A cold air intake (CAI) is usually an aftermarket assembly of parts used to bring relatively cool air into a car
A car, or an automobile, is a motor vehicle with wheels. Most definitions of cars state that they run primarily on roads, seat one to eight people, have four wheels, and mainly transport people rather than cargo. There are around one billio ...
's internal-combustion engine
An internal combustion engine (ICE or IC engine) is a heat engine in which the combustion of a fuel occurs with an oxidizer (usually air) in a combustion chamber that is an integral part of the working fluid flow circuit. In an internal comb ...
.
Most vehicles manufactured from the mid-1970s until the mid-1990s have thermostatic air intake systems that regulate the temperature of the air entering the engine's intake tract, providing warm air when the engine is cold and cold air when the engine is warm to maximize performance, efficiency, and fuel economy. With the advent of advanced emission controls and more advanced fuel injection methods, modern vehicles do not have a thermostatic air intake system and the factory-installed air intake draws unregulated cold air. Aftermarket cold air intake systems are marketed with claims of increased engine efficiency and performance. The putative principle behind a cold air intake is that cooler air has a higher density
Density (volumetric mass density or specific mass) is the ratio of a substance's mass to its volume. The symbol most often used for density is ''ρ'' (the lower case Greek letter rho), although the Latin letter ''D'' (or ''d'') can also be u ...
, thus containing more oxygen per volume unit, than warmer air.
Design features
Some strategies used in designing aftermarket cold air intakes are: *Reworking parts of the intake that createturbulence
In fluid dynamics, turbulence or turbulent flow is fluid motion characterized by chaotic changes in pressure and flow velocity. It is in contrast to laminar flow, which occurs when a fluid flows in parallel layers with no disruption between ...
to reduce air resistance.
*Providing a more direct route to the air intake by eliminating muffling devices.
*Shortening the length of the intake.
*Placing the intake duct to use the ram-air effect to give positive pressure at speed.
Construction
Intake systems come in many different styles and can be constructed from plastic, metal, rubber (silicone) or composite materials (fiberglass
Fiberglass (American English) or fibreglass (English in the Commonwealth of Nations, Commonwealth English) is a common type of fibre-reinforced plastic, fiber-reinforced plastic using glass fiber. The fibers may be randomly arranged, flattened i ...
, carbon fiber
Carbon fiber-reinforced polymers (American English), carbon-fibre-reinforced polymers ( Commonwealth English), carbon-fiber-reinforced plastics, carbon-fiber reinforced-thermoplastic (CFRP, CRP, CFRTP), also known as carbon fiber, carbon comp ...
or Kevlar
Kevlar (para-aramid) is a strong, heat-resistant synthetic fiber, related to other aramids such as Nomex and Technora. Developed by Stephanie Kwolek at DuPont in 1965, the high-strength material was first used commercially in the early 1970s as ...
). Tubing can be steel, stainless steel, aluminum, plastic, or a combination of materials. The most efficient intake systems utilize an airbox
An airbox is an empty chamber on the inlet of most combustion engines. It collects air from outside and feeds it to the intake hoses of each cylinder.
Older engines drew air directly from the surroundings into each individual carburetor. Modern ...
which is sized to complement the engine and will extend the powerband of the engine. The intake snorkel (opening for the intake air to enter the system) must be large enough to ensure sufficient air is available to the engine under all conditions from idle to full throttle.
The most basic cold air intake consists of a long metal or plastic tube leading to a conical air filter. Power may be lost at certain engine speeds and gained at others. Because of the reduced covering, intake noise is usually increased.
Some intakes use heat shields to isolate the air filter from the rest of the engine compartment, providing cooler air from the front or side of the engine bay. This can make a big difference to intake temperatures, especially when the car is moving slowly. Some systems, called "fender mount," move the filter into the fender wall instead. This system draws air up through the fender wall, which provides even more isolation and still cooler air.
Cold air intake efficiency
The following items can have an effect on CAI efficiency: *Output location of the CAI unit. *Obstruction by side and front parts of the vehicle (e.g., headlights). *Length and geometry of intake air tube. The shortest length tube with a smooth interior has a positive effect on increasing airflow.See also
* Carburetor heat * Heated air inlet * Warm air intake *Ram-air intake
A ram-air intake is an intake design which uses the dynamic air pressure created by vehicle motion, or ram pressure, to increase the static air pressure inside of the intake manifold on an internal combustion engine, thus allowing a greater mass ...
* Intercooler
An intercooler is a heat exchanger used to cool a gas after compression. Often found in turbocharged engines, intercoolers are also used in air compressors, air conditioners, refrigeration and gas turbines.
Internal combustion engines
Mo ...
References
{{DEFAULTSORT:Cold Air Intake Automotive engine technologies Vehicle modifications