dualoverheadcam

A dual overhead camshaft (DOHC) engine is a type of internal combustion engine that features two camshafts positioned directly above the cylinder head. This arrangement contrasts with older single overhead camshaft (SOHC) designs, which have only one camshaft. In a DOHC engine, each camshaft typically operates a set of valves for each cylinder. One camshaft is usually responsible for the intake valves, while the other handles the exhaust valves. This separation allows for more precise control over valve timing, which can improve engine performance and efficiency.

The DOHC configuration offers several advantages. By having dedicated camshafts for intake and exhaust, engineers can optimize the timing and lift of each valve independently. This leads to better cylinder filling during intake and more efficient scavenging of exhaust gases. Consequently, DOHC engines often achieve higher horsepower and torque outputs compared to SOHC or overhead valve (OHV) engines of similar displacement. They also tend to rev more freely and can operate at higher engine speeds.

Another benefit of DOHC is the potential for simpler valvetrain design for certain configurations, such as eliminating rocker arms in some designs. This can reduce mechanical friction and inertia, contributing to improved responsiveness and efficiency. However, DOHC engines can be more complex and expensive to manufacture due to the increased number of parts and the need for precise alignment of the two camshafts. Maintenance can also be more involved. Despite these complexities, the performance and efficiency gains have made DOHC a common and preferred configuration in many modern automotive engines.