AirDog® Fuel Systems 101: What do Fuel Air Separation Systems Do?
Few diesel engine components improve fuel efficiency, power, and acceleration while reducing engine wear and tear and exhaust emissions. As the world’s first and only system to effectively remove air from diesel fuel and keep water and other contaminants from entering the engine, the AirDog® Heavy Duty Diesel Fuel Systems provides a combination of benefits that makes them the fuel system of choice for leading truckers.
Fuel air systems are designed to remove air and vapor from your fuel supply before it reaches the injectors. A fuel air system ensures consistent pressure fuel delivery into the combustion chamber for optimal burn. By reducing aeration in the fuel, it improves atomization during the pre-combustion stage, allowing the intake manifold to receive only clean, dense fuel. This process benefits the fuel injection systems by ensuring a steady amount of fuel is delivered, resulting in a cleaner burn and more power. Proper spray fuel patterns from each fuel injector help prevent engine knock, improve fuel economy, and extend component life.
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If you do not yet have an AirDog® fuel system on your truck, this article will explain how our systems work and the benefits they provide to those who drive, maintain, or own heavy-duty trucks.
As a truck rolls down the road, hitting bumps and making turns, the diesel fuel in the tank sloshes around, mixing air bubbles into the fuel. Contrary to popular belief, those air bubbles don’t float up and out of the fuel quickly enough to prevent them from entering the fuel line and onto the engine. Besides air, moisture also enters the fuel due to improperly sealed storage tanks or through condensation in the fuel tank as the outside air warms and cools. Both situations present problems because diesel engines do not burn fuel with entrained air as efficiently as pure diesel fuel, and the problem becomes worse when the fuel contains moisture.
Knowing that air and moisture in diesel fuel affect fuel system efficiency, consider how the typical fuel filter functions. By design, most fuel filters perform one job: they trap solid contaminants in the fuel before they enter the engine. While trapping solids is critical, it is insufficient because standard fuel filters do not remove air and moisture, and performing those steps makes AirDog® systems different.
While the AirDog® fuel system provides more benefits than a typical fuel filter, it remains simple in concept. The first step involves passing the fuel through a water separator to eliminate moisture and large particulates from the fuel. From there, the fuel enters the AirDog® Fuel Preporator, the world’s first patented system that removes air from the fuel. After separating the air and fuel, the AirDog® fuel system sends the air with a trickle of fuel back to the fuel tank. The remaining air-free diesel fuel then flows to the engine at a regulated positive pressure, which provides another advantage of AirDog® fuel systems.
Ordinarily, the fuel pump pulls fuel through a primary filter, which has been a longstanding problem because fuel pumps are inefficient under suction. AirDog® fuel systems include integrated fuel pumps to push the fuel through the filter, preventing air or vapor from reentering the fuel. Pushing air-free fuel also prevents the engine’s fuel pump from cavitating and producing vapors that might enter the fuel, solving a problem commonly experienced when driving at higher elevations.
Incorporating an AirDog® fuel system into your vehicle can make a big difference in your operation, so let’s focus on the three most important benefits.
A notable advantage of AirDog® fuel systems is improved fuel efficiency. The system ensures optimal combustion by providing the engine with clean, air-free fuel, resulting in better mileage and fewer trips to the pump. Typically, trucks using AirDog® fuel systems are several tenths of a mile per gallon more efficient than comparable units with standard fuel filters. Those savings add up quickly, with many users recouping the cost of the AirDog® fuel system within months of installation, depending on their miles driven and conditions.
Optimizing fuel combustion also results in lower emissions, which provides environmental benefits and reduces wear and tear on truck emission systems while lengthening maintenance cycles and reducing parts and labor costs.
Air-free fuel promotes proper cooling and lubrication, improving overall engine performance. This translates into better throttle response, smoother acceleration, improved power delivery, and reduced wear and tear. Drivers experience a smoother ride and have less need to downshift as trucks better hold their gears. Not only does this benefit the bottom line directly, but it also makes for happier drivers, who are the lifeblood of the fleet.
Another benefit of air separation is that injectors stay cooler and are better lubricated, promoting longevity. Without an AirDog® fuel system, the presence of air and vapor in the injector delays the pressure buildup and injection, resulting in retarded injection timing. In addition, the air bubbles are not evenly distributed in the fuel, so the amount of entrained air entering the injector varies from injection to injection. In addition, higher amounts of air retards the injection timing, which results in low torque or power output, increased fuel consumption, increased exhaust emissions, rough idle/wet cylinder, and poor throttle response. AirDog® fuel systems solve these problems by eliminating entrained air from the fuel.
To complete the package, AirDog® products are proudly manufactured in the U.S.A. and come with a four-year limited warranty, which is four times longer than the typical engine whose performance and life the AirDog® fuel system enhances. That makes the AirDog® fuel system the complete package.
Fuel air separation systems play a critical role in ensuring that your diesel engine receives only clean, dense fuel before entering the combustion chamber, which has a major impact on overall engine performance. Entrained air in diesel fuel can disrupt the amount of fuel delivered to the diesel injection components, leading to inconsistent combustion and reduced power output. By removing air and vapor before the fuel reaches the injector system, AirDog fuel air separation systems help maintain a steady injection flow that supports proper burn characteristics and smoother operation.
In a diesel engine, air-free diesel fuel entering the combustion chamber enables the injection system to deliver the precise amount of fuel needed at the right timing. This fuel quality and consistency ensure that the atomization process is efficient, which improves engine performance, reduces emissions, and enhances fuel efficiency. Cleaner fuel also means the fuel pump and fuel injectors operate under optimal conditions, helping extend component life and reduce costly wear.
Without an effective fuel air separation stage, air bubbles and vapor can travel through the fuel line and into the injection system. These air pockets can interrupt the steady flow of diesel and compromise the precise pressure and volume control needed for modern diesel engines. AirDog systems solve this by integrating a high-pressure pump that pushes air-free fuel through the filtration system and into the engine, preventing it from reaching the injectors with any entrained air.
By ensuring that only clean, air-free diesel reaches the combustion chamber, fuel air separation systems help you get the most out of your diesel injection system, which results in better combustion, improved throttle response, and more reliable overall engine performance.
AirDog® fuel systems solve problems that have troubled diesel engines since they first hit the road. AirDog® is the world’s first patented and only system that effectively removes air from diesel fuel and keeps water and other contaminants from entering the engine. By ensuring the engine combusts only pure diesel fuel, AirDog®-equipped engines consume less fuel, perform better, and last longer, making for a startlingly attractive combination of benefits. Whether you are speccing new or want to enhance an existing engine, you will not find a harder-working and more loyal friend than an AirDog® fuel system.
What is a fuel air system?
A fuel air system, also called a fuel air separation system, removes entrained air and vapor from diesel fuel before it reaches the injectors. The AirDog® fuel system also removes water and particulates. It then delivers clean, air-free fuel to the engine at a regulated positive pressure, which supports consistent injection and a complete burn.
What is entrained air in diesel fuel?
Entrained air is air that becomes mixed into diesel as fuel sloshes in the tank during bumps, turns, and braking. These bubbles do not rise out of the fuel fast enough to stay out of the fuel line. They travel with the fuel to the injection system, where they disrupt fuel delivery and combustion.
Why doesn’t my standard fuel filter remove air?
Standard fuel filters are designed to do one job: trap solid contaminants. They are not built to separate entrained air, and they do not remove moisture to the level a modern diesel engine requires. The AirDog® fuel system adds dedicated water separation and air removal stages to close that gap.
How does the AirDog® fuel system remove air from diesel fuel?
Fuel first passes through a water separator that removes moisture and large particulates. It then enters the patented AirDog® Fuel Preporator, which separates air from the fuel. The separated air returns to the tank with a trickle of fuel. The remaining air-free diesel flows to the engine at a regulated positive pressure.
How does entrained air affect injector life?
Air and vapor in the injector delay pressure buildup and retard injection timing. Because bubbles are unevenly distributed, the amount of air varies from one injection to the next. Injectors also run hotter and receive less lubrication. Removing entrained air keeps injectors cooler and better lubricated, which promotes longer service life.
How much can an AirDog® system improve fuel economy?
Trucks equipped with AirDog® fuel systems are typically several tenths of a mile per gallon more efficient than comparable units with standard fuel filters. Results vary based on fuel quality, driver habits, duty cycle, terrain, and miles driven. Even so, many operators recoup the cost of the system within months of installation.
What performance gains will drivers notice?
Drivers typically report better throttle response, smoother acceleration, and improved power delivery. Trucks hold their gears better, which reduces the need to downshift on grades. The improvement is especially noticeable at higher elevations, where traditional fuel systems often struggle with cavitation and vapor.
Why is positive fuel pressure better than suction?
Factory fuel pumps are inefficient when pulling fuel under suction. Suction allows the pump to cavitate, which creates vapor that can enter the fuel. The integrated AirDog® pump pushes fuel through the filters and feeds the engine with positive pressure. That keeps air and vapor out of the system.
Does an AirDog® fuel system help reduce emissions?
Yes. Air-free fuel combusts more completely, which lowers exhaust emissions. More efficient combustion also reduces wear on truck emission systems, which can lengthen maintenance cycles and lower parts and labor costs.
Does the AirDog® system replace my primary fuel filter?
Yes. The AirDog® system takes the place of the truck’s primary fuel filter. It combines water separation, particulate filtration, air removal, and an integrated fuel pump in a single system. The filters mount on the frame for easy access and can be changed with a standard wrench.
Is AirDog® a good fit for new trucks and existing engines?
Yes. Whether you are speccing a new truck or upgrading an existing engine, an AirDog® fuel system delivers the same core benefits: better fuel economy, stronger performance, and longer injector life. Every system is made in the U.S.A. and backed by a four-year limited warranty.