DVVT is dual variable valve timing technology, and CVVT is continuously variable valve timing technology. What is valve timing? Timing can be understood as “acting at the specified timing”. For example, the engine has ignition timing, which means that the spark plug is ignited at the specified time. The purpose of valve timing is to open or close the intake and exhaust valves at the specified time. When the engine is running, the intake and exhaust valves open and close successively. The mechanism that controls the opening and closing of the valves is called the valve timing system. The crankshaft drives the camshaft through a timing belt or timing chain, and then the camshaft drives the valves.
Since the crankshaft rotates twice to complete a cycle, the intake and exhaust valves are opened and closed once respectively, so the crankshaft rotates twice and the camshaft rotates once. There are several cams on the camshaft. The arrangement order and speed of the cams are set according to the operating law of the piston, and the corresponding valves can be opened in time.
When the engine is running, the intake and exhaust valves open or close at the set timing. Both CVVT and DVVT can be said to be the development and update of VVT. Their theoretical principles and purposes are the same, but CVVT and DVVT can achieve better results than VVT with new technologies.
