The core function of camshaft: The camshaft of the pickup engine is a key component in the valve train. Its main task is to control the opening and closing time and lift size of the valve, so as to ensure that the engine has sufficient air intake and exhaust. The cam profile on the camshaft is like a precise "baton", dominating every movement of the valve.
Basic profile curve: The profile of the cam is usually composed of a base circle, a buffer section and a working section. The base circle is the basic part of the cam. When the cam runs to the base circle and contacts the valve tappet, the valve is in a closed state to maintain the sealing of the engine. The buffer section is responsible for slowing down the impact at the moment of valve opening and closing to avoid excessive wear of parts.
Control the valve opening moment: The design of the starting point of the working section of the cam profile determines the precise moment of valve opening. As the cam rotates, when the working section begins to contact the tappet, the tappet moves upward under the push of the cam profile, driving the valve to overcome the spring force and open. Designers will carefully carve this opening point according to the engine's operating conditions, such as idling, high-speed driving, heavy-load climbing, etc., to ensure that the engine can inhale the right amount of air under different operating conditions.
Adjusting valve lift: The shape and slope of the working section accurately control the lift of the valve. During the continuous rotation of the camshaft, the valve tappet continues to climb along the cam profile, and the valve lift increases accordingly. Different engine operating conditions have different requirements for valve intake volume. By optimizing this part of the cam profile design, the valve can be opened accurately to different degrees to meet the power output requirements.
Control valve closing: The end of the cam profile working section determines the valve closing time. When the cam runs to this point, the valve quickly falls back and closes under the action of the spring force to prevent exhaust gas backflow or fresh mixture leakage. Similarly, this closing node is also carefully set based on the engine combustion cycle characteristics.
Optimize cam profile: Nowadays, with the help of advanced computer simulation technology, engineers can repeatedly simulate the movement of valves under different cam profiles, and continuously optimize and adjust them in combination with the actual performance of the engine, making the camshaft profile design more accurate and making the valve opening and closing perfectly match the engine working conditions.
Impact and significance: The accurate camshaft profile design not only improves the power and economy of the pickup engine, but also reduces exhaust emissions, laying a solid foundation for the reliable operation and energy saving and environmental protection of the pickup.
