Most readers in their daily lives have heard the conclusion that “whether a car is powerful enough to be judged by its exhaust pipe”, some readers believe that the more exhaust pipes there are, the larger the diameter of the exhaust pipe and the louder the exhaust pipe, which means the more powerful the vehicle. In this line of thought, many owners of friends also put their car exhaust system modification, so that it has a more exaggerated appearance, more exaggerated noise, to highlight the strong vehicle power. But is it really possible to change the exhaust system?In this article, you’ll learn more about the Consequences of Blind Exhaust.
1. the Exhaust Principle of a Car
1. Structural Design of Exhaust System
The structure design of the exhaust system, in general, the automotive exhaust system mainly consists of exhaust manifold, three-way Catalytic converter, mid-section muffler, rear muffler and many other components. One end of the exhaust manifold is connected with the engine, the other end is connected with the front exhaust pipe, and then the middle section and the back section are connected in turn, except the two ends of the exhaust manifold are fixed by bolts, the rest of the line is suspended under the car’s body with rubber, which can move up and down, left and right, so the vibrations from the exhaust don’t travel into the car.
In addition to exhaust gas, the muffler in the exhaust system also acts as a muffler and affects the power of the car. In fact, gasoline makes a lot of noise when it is burned violently in the cylinder. The main reason why you don’t hear it in your daily driving is that the muffler in the exhaust pipe has succeeded in reducing the noise. If there is no muffler, the sound of the gasoline burning in the cylinder is deafening, and the noise when you step on the gas pedal is even louder than that of a farm tractor./nIn theory, it is generally believed that the exhaust gas from gasoline entering the cylinder after combustion, the sooner the better, but in fact, it is not the case, exhaust too fast or too slow will have some impact on the car. Because this involves the “exhaust back pressure”, “valve alternates” concept.
Exhaust back pressure refers to the exhaust resistance, exhaust pipe is longer, and there is a certain bend, so in the exhaust gas will have resistance, resistance is expressed by exhaust back pressure. If the exhaust back pressure is too high, it will result in the increase of the engine’s inflation loss, the decrease of the combustion efficiency, the decrease of the power output and the poor fuel economy, as a result, the low-speed engine torque output is reduced, the vehicle starts weakly, the exhaust sound quality also becomes very poor.
2. Four-stroke Engine
As we all know, the common four-stroke engine on the market is divided into four steps: intake, compression, ignition work, exhaust. The engine is driven by a camshaft, and the intake valve opens first, drawing fresh air from the intake valve as the cylinder descends. Then close the intake valve, start compression, ignition to do work, finally the exhaust valve open, the piston upward exhaust from the exhaust valve, from this point, the engine completed a cycle./nThe valve overlap is the last step of the engine cycle. The intake valve is opened ahead of time before the piston reaches TDC during the exhaust process, the intake and exhaust valves are in an open position called valve overlap.
Valve overlap causes the piston in the exhaust process to be pushed into the intake port of the intake valve, in addition to the last part of exhaust gas being expelled from the exhaust valve. Therefore, in the next round of work cycle, the intake system to this part of the “exhaust” into the cylinder block, and then breathe in fresh air. Many readers will wonder why the engine doesn’t wait until the exhaust process is over before opening the intake valve, so what’s the use of inhaling a little exhaust?
For a low-speed engine of an ordinary family car, the cylinder compression mixture is relatively slow, so at the moment of ignition, the mixture temperature is not high enough, which causes the mixture to burn inadequately. So, in the speed range of the engine, the valves overlap, and the polymer carbon chain, which is not completely releasing energy, is ignited by the next round of ignition, compared to the fresh gasoline molecules, such polycarbon molecules, which burned in the last round, are more likely to ignite because of their high temperatures and relatively small molecules.
There is no doubt that the benefits of valve overlap are obvious, allowing the engine to increase torque at low speeds and save fuel, while the unburned polymer carbon chain can be reused.
2. Conclusion——use Original Exhaust
We believe that after understanding the above engine intake valve, exhaust valve work logic, the vehicle exhaust pipe design principle and work logic have a general understanding. As to why some vehicles will use one exhaust pipe, some vehicles will use two exhaust pipes, the main reason is based on the designers of the vehicle engine exhaust back pressure, valve overlap of the actual needs and design. Therefore, in the case of the original exhaust, the vehicle power is really strong can be identified by the number of exhaust, caliber.
Many times when we walk down the street, we see some car owners choose to increase the number of exhaust pipes or increase the diameter of exhaust pipes in order to make their vehicles more sporty. Although this behavior for some people really help increase the perception of the vehicle, but in a way for their own safety hidden danger. Therefore, brother cylinder does not suggest that we simply for the aesthetic to modify the vehicle, to maintain the original exhaust is undoubtedly the best choice.