1. SOHC
is a single overhead camshaft design is provided only one camshaft in the cylinder head. This design uses only an in-line cylinder engine camshaft placed in the cylinder head side, and a V-shaped cylinder engine two camshafts is required, are placed on the side of the cylinder bank.
single overhead camshaft (SOHC)
ram single overhead camshaft design, the
needs to reciprocate relatively to the total mass member and the same conditions engine significantly reduced. Thus SOHC engine speed can be improved, thereby improving the power output of the engine in the case where the output torque is the same. In this design, the camshaft can be opened and closed by the rocker arm or directly controlling the valve, as without overhead valve pushrod engines as required by a tappet, a rocker arm and the long pushrod engine group movement of the cam on the camshaft is transmitted to the valve cover in the cylinder.
compared to the pusher structure, single overhead camshaft design enables the engine structure (mainly valve structure) is more compact. This advantage is particularly significant when at the same time using multi-valve design (ie a cylinder with more than two valves). But sometimes in order to meet specific design requirements of the engine, while using a single overhead camshaft also need some additional components. Hillman urchin (Hillman Imp) of the 8-cylinder 4-valve engines is the use of a typical single overhead camshaft engine valve clearance adjusting shims and adjusting the valve piston. Hillman urchin is a small two-door sedan design and manufacture of a early 1960s. Thereafter alloy engine opposed vertices by Coventry (Coventry Climax) series of improvements comes racing engines. In this engine, the intake and exhaust valves of the engine is placed on the same side of the body, and thus the cylinder head without using a crossflow (crossflow cylinder head) design, while facilitating the work of the spark plug.
However, single overhead projectionAxle also has its drawbacks. Since the intake and exhaust valves at different locations in the intake port, the accuracy of the valve opening and closing time will be affected. In the early 1980s, Toyota (Toyota) and VW (Volkswagen) have also been used to directly drive the two valves per cylinder single overhead camshaft engine, the structure of the parallel valve so that the volume further compact. Toyota uses hydraulic tappets, and uses the Volkswagen barrel tappet, also equipped with a gasket lash adjuster to precisely control the valve opening and closing time. In all the valve arrangement form single overhead camshaft engine, such a design may be the most compact and simple.