Intake and exhaust efficiency of diesel engine

by Generator D. Diesel Generator

To improve the efficiency of intake and exhaust, the more fresh combustible mixture entering the cylinder, the cleaner the exhaust emission after combustion, the more sufficient combustion, the more heat used for work, and the corresponding improvement of power performance.

1.Adopt secondary air intake device.

By installing an independent secondary air intake device on the intake manifold, the amount of air entering the cylinder per unit time is increased, the intake resistance is reduced, the charging efficiency is improved, the combustion is more full, and the engine power is also significantly improved.

2.Adopt multi valve.

Increasing of intake and exhaust valve improves intake and exhaust area and flow rate of high-speed air flow, and exhaust efficiency of diesel engine. With multi valves, the volume of each valve is reduced, the weight is reduced, and the motion inertia is small, which is also conducive to high-speed movement. Therefore, the engine adopts multi valve mechanism to improve the intake efficiency and power. Multi valve mainly aims at the intake and exhaust efficiency at high speed, but the intake and exhaust efficiency at low speed is reduced, so multi valve should be set according to the situation.

3.Improve intake and exhaust valve travel.

The change of valve stroke will change the intake and exhaust area and improve the intake and exhaust efficiency. When the engine is at low speed, the use of a smaller valve stroke reduces the intake area, which is conducive to improving the intake and exhaust efficiency at low speed; when the engine is at high speed, the use of a larger valve stroke increases the intake area, which is conducive to improving the intake efficiency at high speed.

According to the working cycle of the engine, the intake and exhaust valves of the engine are called the valve distribution phase. The accuracy of valve timing has a great influence on the dynamic performance of the engine. If the valve timing is not accurate, it will lead to insufficient intake air and unsmooth exhaust, affect the formation quality of the mixture, cause incomplete combustion, and reduce the power of the engine.

Due to the inertia of exhaust gas and fresh air in motion, the intake and exhaust have a certain lag period. In order to make the exhaust gas in the cylinder more clean and fresh air enter more fully, it is necessary for the intake and exhaust valves to open at the same time, that is, the valve overlap angle, that is, the valve distribution phase. Therefore, when the engine is at low speed, a smaller valve overlap angle is used, on the contrary, a larger valve overlap angle is used, so that the intake and exhaust efficiency can be improved, and the power performance of the engine can be improved.