The intercooler is usually only visible in vehicles equipped with a turbocharger. Because the intercooler is actually a supporting component of turbocharging, its function is to reduce the high-temperature air temperature after turbocharging, lower the thermal load of the engine, increase the intake air volume, and thus increase the engine power. For turbocharged engines, the intercooler is an important component of the turbocharging system. Whether it is a supercharged engine or a turbocharged engine, an intercooler needs to be installed between the turbocharger and the intake manifold. Taking a turbocharged engine as an example, a brief introduction to the intercooler will be given below
One of the reasons why turbocharged engines have greater power than ordinary engines is that their ventilation efficiency is higher than that of natural intake engines. When air enters turbocharging, its temperature will significantly increase and its density will correspondingly decrease. The intercooler plays a role in cooling the air, and high-temperature air is cooled by the intercooler before entering the engine. If there is a lack of an intercooler and the high temperature air after turbocharging directly enters the engine, it may cause engine detonation or even damage and stall due to high air temperature.
The intercooler is usually found on vehicles equipped with turbocharging. Because the intercooler is actually a supporting component of turbocharging, and its function is to improve the ventilation efficiency of the turbocharged engine.
effect
The function of the intercooler is to lower the intake temperature of the engine. So why lower the intake temperature?
(1) The temperature of the exhaust gas emitted by the engine is very high, and the heat conduction through the turbocharger will increase the temperature of the intake air. Moreover, during the compression process, the density of air increases, which also leads to an increase in the temperature of the air discharged from the turbocharger. As the air pressure increases, the oxygen density decreases, thereby affecting the effective charging efficiency of the engine. If you want to further improve the inflation efficiency, you need to lower the intake temperature. Data shows that under the same air-fuel ratio conditions, for every 10 ℃ decrease in the temperature of the charge air, the engine power can increase by 3% to 5%.
(2) If uncooled boost air enters the combustion chamber, it will not only affect the charging efficiency of the engine, but also easily lead to high combustion temperature of the engine, causing detonation and other faults, and increase the content of NOx in the engine exhaust, causing air pollution.
In order to address the adverse effects caused by the temperature rise of the air after turbocharging, it is necessary to install an intercooler to reduce the intake temperature..
(3) Reduce engine fuel consumption.
(4) Improve adaptability to altitude. In high-altitude areas, using intercooler can use a higher pressure ratio compressor, which allows the engine to achieve greater power and improves the adaptability of the car.
(5) Improve turbocharger matching and adaptability.
Maintenance methods
The air-cooled intercooler and radiator are installed together in front of the engine, relying on the suction fan and the surface air of the car for cooling. Poor cooling of the intercooler can lead to insufficient engine power and increased fuel consumption. Therefore, regular inspection and maintenance of the intercooler should be carried out, mainly including:
External cleaning
Due to the installation of the intercooler at the front, the cooling fin channel of the intercooler is often blocked by leaves, oil sludge (hydraulic oil overflowing from the steering oil tank), etc., which hinders the heat dissipation of the intercooler. Therefore, this area should be cleaned regularly. The cleaning method is to use a water gun with relatively low pressure to slowly flush from top to bottom or from bottom to top at an angle perpendicular to the plane of the intercooler, but never diagonally to prevent damage to the intercooler.
Internal cleaning and inspection
The internal pipes of the intercooler often contain dirt such as oil sludge and gum, which not only narrows the air flow channel but also reduces the cooling heat exchange capacity. Therefore, maintenance and cleaning are also necessary. Generally, every year or during engine overhaul or welding repair of the water tank, the interior of the intercooler should be cleaned and inspected.
Cleaning method: Add an aqueous solution containing 2% caustic soda (temperature should be between 70-80 ℃) into the intercooler, fill it up, wait for 15 minutes, and check for any water leakage in the intercooler. If necessary, it should be disassembled for inspection and repaired by welding (the same as repairing the water tank); If there is no water leakage, shake back and forth repeatedly, pour out the washing solution, and then fill it with a clean aqueous solution containing 2% soda ash for rinsing until it is relatively clean. Then add clean hot water (80-90 ℃) for cleaning until the released water is clean. If the outside of the intercooler is stained with oil, it can also be cleaned with alkaline water. The method is to soak the oil stain in alkaline solution and remove it with a brush until it is clean. After cleaning, use compressed air to blow dry the water inside the intercooler or let it cool naturally. When installing the intercooler, do not connect the intercooler to the engine connection pipe first, start the engine, and wait until there is no moisture at the intercooler outlet before connecting the engine intake pipe. If severe dirt is found inside the intercooler core, carefully inspect the air filter and intake pipelines for any leaks and troubleshoot.
The biggest problem with turbochargers is that the distance between the intake port that draws in fresh air and the high-temperature exhaust is very close, and the temperature of the fresh air drawn in will also increase significantly after compression. Therefore, even mechanical turbocharged engines without the influence of high exhaust temperatures need to use intercoolers to cool the intake air. The temperature of compressed air will increase. The simplest example is the air pump used to inflate tires. If you don't believe it, you can touch the air pump that is inflating it and know how terrifying the heat accumulated by air compression is. In addition, through knowledge of chemistry and physics, we can know that the lower the temperature, the higher the oxygen content in the air. Some people may ask: What does this matter? You should know that fuel combustion requires oxygen in the air, and the more oxygen there is, the more fuel can be burned, thereby unleashing more power. Friends who want to learn more can refer to the relevant introduction in "Inhalation System". The intercooler is an efficient radiator that primarily cools fresh air before it enters the engine. You can imagine that the intercooler is located in front of the radiator, so it can be directly impacted by the cold air blowing from the front, and it also needs to be located behind the air filter, turbocharger, or mechanical supercharger. The actual situation is indeed like this. Most cars are equipped with an intercooler located in front of the radiator, and the cooling effect is indeed better than some overhead layout intercoolers. However, this will affect the airflow blowing into the radiator to some extent. Therefore, in some extreme situations, such as on the track, it is necessary to upgrade the radiator to control the engine temperature.
Working Principle
Using a well-designed intercooler can provide an additional 5% -10% of power.
Some cars also use overhead intercoolers, which obtain cooling air through openings in the engine hood. Therefore, before the car starts, the intercooler will only be blown by some hot air from the engine compartment. Although the heat dissipation efficiency is affected, the fuel consumption of the engine will decrease significantly because the intake temperature will rise in such a situation, indirectly reducing the engine's working efficiency. However, for powerful turbocharged cars, the unstable start caused by excessive power can be alleviated in this situation. Subaru's Impreza series is a typical example of overhead intercoolers. In addition, the biggest advantage of the overhead intercooler layout is that it can effectively shorten the stroke of compressed gas reaching the engine.