What does the dynamic effect of the intake pipe mean?
1 Answers
The opening of the intake valve and the movement of the piston generate expansion waves in the intake system. This expansion wave starts from the intake valve, propagates to the end of the pipe at the local speed of sound, where it turns into a compression wave and travels back to the intake valve at the same speed. If this compression wave reaches the intake valve when it is open, the intake airflow is enhanced, the cylinder charge coefficient increases, and the torque also rises. This phenomenon is called the dynamic effect of the intake pipe. Below is a related introduction: 1. Intake stroke: At this time, the piston is driven by the crankshaft to move from top dead center to bottom dead center, while the intake valve opens and the exhaust valve closes. As the piston moves from top dead center to bottom dead center, the volume above the piston increases, the gas pressure in the cylinder decreases, creating a certain vacuum. Since the intake valve is open, the cylinder connects with the intake pipe, and the air-fuel mixture is drawn into the cylinder. When the piston reaches bottom dead center, the cylinder is filled with fresh air-fuel mixture and residual exhaust gases from the previous cycle. 2. Compression stroke: The piston moves from bottom dead center to top dead center, with both intake and exhaust valves closed. The crankshaft rotates under the inertia of the flywheel, pushing the piston upward via the connecting rod. The gas volume in the cylinder gradually decreases, compressing the gas, and the pressure and temperature of the air-fuel mixture in the cylinder rise accordingly.
