Many of the cars now have a striking "T" in their engine, and the T-word proves that it is a supercharged engine. As we all know, the turbocharged engine adds a turbine device to the original engine. In operation, the excess energy generated by the turbine itself must be reasonably conducted out. This requires a device to be "energy-neutralized". This is the intercooler.

　　The intercooler will increase the air resistance, reduce the pressure of the charge air, reduce the supercharging effect, and slow down the engine response. However, this effect is insignificant compared to the effect of the intercooler on the engine boosting power. .

　　Air or water?

　　To cool the air, there are two ways. One is to cool down by the cold wind that hits the head when the vehicle is driving, and the other is to use water cooling. The principle of the former is the same as that of our household refrigerators and air conditioners. It is to let the air pass through a pipe, increase the contact area between the pipe and the surrounding air, and then cool it by the surrounding air. An air-cooled intercooler placed above the engine.

　　Water cooling is just the opposite of air cooling. It is to put a cooler into the intake pipe and let the pressurized hot air flow through. In the cooler, there is cooling water that constantly flows to take away the charge air.

　　The solid line indicates the flow of the air and the dotted line indicates the flow of cooling water.

　　First, following the previous topic, when the air is compressed by the supercharger, the temperature will rise, which is a basic physical principle. How much will the temperature of the pressurized gas rise? This depends on the operation of the supercharger. The higher the speed, the higher the boost pressure and the higher the temperature rise. Generally, it can rise by about 40-60 degrees, plus the original temperature of the air. The gas is already very hot.

　　The effect of high temperature gas on the engine is mainly at two points: First, the volume of the air is large, which is equivalent to less air sucked by the engine; and the second point is more important, the high temperature air is particularly unfavorable for engine combustion, and the power is reduced. Emissions will get worse. Under the same combustion conditions, the engine power drops by about 3% to 5% for every 10 °C increase in the temperature of the charge air. This problem is very serious, and the increased power will be offset by the high air temperature. In order to solve these problems, we need to re-cool the pressurized air and send it to the engine. The part that takes on this important task is the intercooler. The intercooler sounds cool, but the principle and structure are no different from the radiators of our household refrigerators and air conditioners.

　　Side effects: engine response slows down, turbo lag becomes severe, why should intercooler

　　In general, the larger the intercooler, the smaller the internal airflow loss and the higher the cooling efficiency, and the longer the airflow stays inside the intercooler, the better the cooling effect. However, the intercooler is like increasing the volume of the intake pipe. The compressed air generated by the supercharger must first fill this volume before it can produce a supercharging effect. If used on turbocharged, the direct performance is that the turbo lag becomes severe; even a supercharged machine can cause the engine to slow down.

　　On the other hand, since the charge air must flow through various pipes, the resistance increases, and the boost pressure is sure to be weakened. However, this weakening is only generated in a short period of time after the accelerator is depressed, because the pressurized air is weakened and the pressure is re-established in the sealed space from the intercooler to the intake valve until the pressure is released. The valve opens. Therefore, the final performance is still that the engine response is slow, and the turbocharged hysteresis will become serious.

　　The intercooler will make the turbo lag more obvious, but it can't be installed. Therefore, how to balance the cooling efficiency and pressure maintenance is the most difficult problem for engineers. The most fundamental method is to reduce the volume of the entire intake pipe, reduce the pipe resistance, and shorten the intake pipe, so the intercooler we see is often close to the engine, not as far away as the radiator. High-boost, large-displacement engines often require a large intercooler because of the large intake air and high temperature. Larger intercooling is easier to see on the top of the engine, so that you can open the air in the bonnet and use the cold air that hits the surface to cool down. This way you can see it on many cars. To, for example, Impreza STI, MINICOOPERS. The advantage of being placed above the engine is that it is compact and has short pipes, making it ideal for use in small cars and modified cars. However, this arrangement is affected by the heat of the engine because it is too close to the engine.

　　Both MINICOOPERS and Impreza STI are open on the hood for intercooler cooling

　　There is also an arrangement in which the intercooler is placed under the front of the net in the car. This method makes full use of the oncoming cold air to dissipate heat, but the pipeline is too long and the layout is more complicated. As it gets closer to the ground, it is more likely to be damaged by sand on the ground.

　　For both cooling methods, it is an external air-cooling system suitable for large intercoolers. The current trend is low-boost engines, do not need too much intercooler, but also to make the engine more compact, many engines are currently water-cooled, put a cooler into the intake pipe, when The air is cooled as it passes by and the structure is very compact.

　　Intercooler used by Volkswagen 1.4TSI

　　The intercooler is a very important component in a supercharged engine that effectively reduces air temperature and increases engine power. In addition to reducing the temperature of the air, we also need to cool the turbocharger and control the boost pressure.

　　The Volkswagen 1.4T turbocharged engine we are familiar with is this way, and Audi's supercharger is also cooled in this form, and the structure is quite compact. Since the intercooler is completely installed inside, it is less damaged by dust and sand.