The engine oil is atomized and sprayed into the engine, which makes the engine burn more completely and saves fuel. If a flame is found, it is because the oil supply exceeds the combustion limit. The resulting combustion is incomplete. Without completely burned gas, the high temperature and narrow space in the exhaust pipe may continue to burn.
Of course, this is not a technical problem, but a problem that basically exists in every engine. Motorcycles will be equipped with exhaust pipes when they leave the factory, so users generally don't see this phenomenon.
Extended data
The fire in the exhaust pipe is not just a patent for super running.
1, this fire-breathing phenomenon usually appears in turbocharged racing cars, modified cars and super-running. As we all know, turbocharging can improve the power of the engine, but it also has the disadvantage of turbo lag.
2. The so-called turbo lag means that you step on the accelerator to the end until the turbo pressure has risen to the maximum.
The engine speed we usually use for driving is not high. Generally, the turbines used in family cars are relatively small. Basically, the engine will be full at one to two thousand revolutions, and the turbine lag of these cars is relatively small.
4. However, some racing cars, modified cars and supercars often use higher speeds and use larger turbines than ordinary cars. The intake pipe was redesigned, and some changes such as medium cooling were added, which made the turbine lag more.
5. The racing car needs to slow down before entering a sharp turn, and needs to accelerate after coming out of the turn. The turbo lag prevents the engine from exerting its maximum power immediately. In order to reduce the lag, the bias ignition system came into being.
6. The principle of partial ignition is not difficult to understand. When the engine is controlled by ECU to release the throttle to slow down, the fuel injector injects fuel into the cylinder but the spark plug does not ignite, so that the combustible mixture in the cylinder directly enters the exhaust system and automatically burns and explodes in the high-temperature exhaust pipe.
7. Then, with a bang, the impact force generated by the explosion pushes the exhaust impeller to continue to rotate, so that the rotation speed of the turbine can be maintained even when the vehicle slows down, and when acceleration is needed, the turbine can immediately reach the maximum pressurization value, thus eliminating the turbine lag.
8. Because the combustible mixture burns in the exhaust pipe, the flame will be removed along the pipe, so you can see the fire. Some racing cars spray more oil, and even can see flames, which is commonly known as "fire breathing".
9. Of course, partial ignition also has disadvantages. Of course, the fuel consumption of vehicles with offset ignition system will be high, and the impact force generated by the explosion of combustible mixture in exhaust pipe will inevitably cause certain damage to turbine blades and exhaust pipe.
References:
Phoenix. Com- exhaust pipe fire is only the patent of super-running?