How often should the air intake system filter be changed?

As the heart of passenger cars and commercial vehicles, the internal combustion engine has been in existence for more than a century. At present, 95% of the gasoline, diesel and natural gas engines commonly used in the industry are designed with four-stroke structure. The general principle is intake, compression, ignition and emission, which is the key link of engine power generation.

In recent years, in order to optimize the power output of the engine, the host factory for the above four links continue to optimize the internal structure of the engine, such as higher cylinder compression ratio, bowl-type piston, delayed ignition, offset crankshaft and other technologies.

As an important part of optimizing in-cylinder efficiency, the efficiency of the intake system affects the fuel utilization of the engine as well as the in-cylinder environment. It has a direct relationship with the power output of the vehicle. So how much do you know about the air intake system? 

The overall structure of a truck's air intake system is similar to that of a passenger car, including the air breather hose, air flow meter, breather hose, air intake hose bracket and cushion, air filter and mounting bracket. The more important parts are divided into intake tube, air flow meter, air filter, air filter outlet line, closed breather connection hose and hose clamps.

The air intake system of Chinese flathead trucks usually extends from the engine compartment under the cab, with air intakes placed around the cab, commonly at the rear of the cab and on top of the cab. Some models also have the air intake in the cowl area in front of the cab, such as all Scania models.  

Generally speaking, truck air intake systems are developed and improved by each manufacturer for their own vehicles in constant driving and calibration, and the important indexes include flow resistance, heat resistance, cold resistance, durability, vibration resistance and other factors.

Since each manufacturer's design ideas are different, in the actual working conditions which design is most in line with our actual car needs?

From the point of view of air quality, dust as well as particles will stay at different horizontal heights according to the environment. For example, in mining areas, gravel plants, large particles, a large amount of dust are generally suspended for a long time in the range of 1-3 meters from the ground. And a large amount of floating dust, suspended particulate matter is often concentrated in the area 12 meters from the ground and above. The closer the vehicle's air intake system is to these two categories, then the total amount of dust and particulate matter inhaled will be a little more.

Although there are air filters or special designs that allow the intake tract to block dust and particles, being in an intake tract with better air quality obviously makes changing the air filter and cleaning the intake tube less frequent. So this explains why many manufacturers nowadays choose to layout the engine air intake at the back of the cab, to avoid direct airflow to inhale more dust and particles.

So is it true that the higher and longer the intake tract, the fresher the air you breathe? There is no guarantee that the height of dust and particulate matter will be consistent in all environments. The position of the intake tract plays a very small part in the cleanliness of a truck's air intake, but it's the material of the air filter, its filtration effect, and its durability that are more important.

At the same time, merely increasing the height of the intake duct will trigger a decrease in the efficiency of the air intake. It takes a certain amount of time for air to enter the engine along with the intake system to perform work, and the growth of the intake system means that the speed at which air is transferred to the engine is reduced and slowed down, which is not conducive to improving vehicle fuel efficiency and power output. In high plateaus above 2000 meters, this situation will also be accompanied by a more obvious decrease in the oxygen content in the air.

When choosing a truck, truckers who frequently travel to and from the plateau should try to choose a truck with a compact layout of the intake system, which helps to improve the efficiency of the air intake.

Under normal atmospheric pressure, the density of air will change as the temperature rises and falls. If the ambient temperature is too high, then the oxygen molecules in the air will expand, and less oxygen will flow through the air intake system per unit quantity, which in turn affects the oil-air mixing ratio in the diesel injection system. The truck will experience abnormalities such as power loss and increased fuel consumption.

In summary, it is not possible to determine which model has a better designed air intake system based on the relevant criteria, as this is influenced by a multitude of factors such as environmental factors, driving habits, and manufacturer's technology.