What does DOHC in the valve train mean?
2 Answers
DOHC in the valve train stands for Double Overhead Camshaft, which features two camshafts separately controlling the intake and exhaust valves, thereby improving intake and exhaust efficiency, reducing fuel consumption, and enhancing high-torque working efficiency. Below is relevant information: Engine Principle: A four-stroke gasoline engine mixes air and gasoline in a specific ratio to form a well-mixed gas, which is drawn into the cylinder during the intake stroke. The mixture is then compressed, ignited, and burned to generate thermal energy. The high-temperature and high-pressure gas acts on the top of the piston, driving the piston to perform reciprocating linear motion, thereby converting mechanical energy through the connecting rod and crankshaft flywheel mechanism. Introduction to the Cylinder: The working chamber of a reciprocating piston internal combustion engine is called the cylinder, with the inner surface of the cylinder being cylindrical. The piston moving reciprocally inside the cylinder is connected to one end of the connecting rod via the piston pin, while the other end of the connecting rod is linked to the crankshaft. The crankshaft is supported by bearings on the cylinder block and can rotate within the bearings, forming the crank-connecting rod mechanism. As the piston moves reciprocally within the cylinder, the connecting rod drives the crankshaft to rotate.
I recently studied the valve train while working on my car. DOHC stands for Dual Overhead Camshaft, where two separate camshafts are installed on top of the engine, one controlling the intake valves and the other managing the exhaust valves. This design allows for faster and more precise valve operation, enabling the engine to reach higher RPMs and deliver more powerful performance, resulting in smoother and more responsive acceleration. While a single camshaft setup might be slightly more fuel-efficient, DOHC is commonly found in sports or performance cars, such as the Honda Civic from Japanese manufacturers. When driving at high speeds, you can really feel the stronger push in your back. Another small advantage is reduced noise due to smoother operation. Of course, daily maintenance isn't much different from a single camshaft engine—just regular oil changes are needed. All in all, it's a progressive design in modern engines.