SOHC and DOHC

SOHC stands for Single overhead camshaft, while the DOHC stands for Double overhead camshaft. Camshaft or Noken has a function to open the suction valve cover and exhaust valves. Duty suction valve for sucking fuel-air mixture into the combustion chamber. Conversely, the exhaust valve has a duty to distribute the remaining combustion to exhaust.
Actually the technology is not only a valve mechanism SOHC and DOHC, but still there is another system called the OHV (Over Head Valve). Mechanism of action of this valve is very simple and has high durability. Placement of its camshaft in the cylinder block is assisted valve lifter and push rod between the rocker arm. OHV mechanism is widely used by truck diesel engines that require only torque. Due to limited technological development, OHV system is rarely used anymore in gasoline engines.



 Function Overhead Camshaft
In a car engine, overhead camshaft valve attached to the handlebars (valves). Note the picture above, the valve is shown by the blue ellipse circle. In the picture above SOHC engine configuration, there are 8 valve which is driven by 8 overhead. The movement of valve opening and closing overhead camshaft driven by a function to process the air intake and fuel for combustion in the cylinder and to exhaust the process of combustion air throw that led to the muffler / exhaust of your car.

SOHC vs. DOHC
As mentioned earlier, the DOHC and SOHC distinguished by the number of pairs of overhead camshafts on each cylinder. To know the advantages and disadvantages DOHC and SOHC, need to know first the concept of an internal combustion engine or engines which have the character of combustion in the engine itself, in this case occurred in the cylinder. The concept is, the more fuel and air that goes to the fuel, the greater the power of the engines. Conversely, the less fuel and air are burned, the less power generated. In this case, DOHC that has the number two overhead camshafts per cylinder pair (a pair more than the SOHC), has the ability to enter the fuel and air more than the SOHC, DOHC engine produces power that is greater than the SOHC engine. As a consequence, DOHC engine would be wasteful because the intake of more fuel than the SOHC engine. So it can be said with a term, "means power DOHC, SOHC economic means". DOHC engines are usually more expensive because it requires a number of parts more than the SOHC is more and more overhead camshaft valve. In addition, the amount of overhead camshaft which require more power also to move more. This will reduce the power generated from the machine itself, although not too much. So the power generated by the machine will be used to move the part a little more on the DOHC engine, although not significantly.