The main function of the exhaust manifold is to collect and discharge the exhaust gas from each cylinder of the engine smoothly, while reducing the resistance in the exhaust process and avoiding mutual interference between cylinders. 

The exhaust manifold is an important component connecting the engine cylinder body. It is designed to effectively collect the exhaust gas generated by each cylinder, and through a specific shape and length design, a good flow and pressure balance is formed between the exhaust gases, thereby reducing resistance and interference. This design not only helps to improve the output power of the engine, but also ensures the smooth exhaust process. The role of the exhaust manifold is mainly reflected in the following aspects:

Concentrated exhaust: The exhaust manifold can collect the exhaust gas from each cylinder and introduce it into the exhaust manifold through one or more pipes, thereby reducing exhaust resistance and improving engine efficiency.

Avoid mutual interference: Through reasonable design, the exhaust manifold can avoid mutual interference between cylinders during the exhaust process, ensure that the exhaust gas from each cylinder can be discharged independently and smoothly, and avoid working interference between cylinders caused by excessive concentration of exhaust gas.

Improve performance: The design and material selection of the exhaust manifold have a direct impact on the performance of the car. A high-quality exhaust manifold can reduce exhaust back pressure and improve engine power performance and fuel economy.

Environmental considerations: In modern cars, the design of the exhaust manifold also takes environmental factors into consideration, such as reducing pollutant emissions and reducing the emission of harmful substances by cooperating with components such as catalytic converters.