4-Valve Technology Explained

4-VALVE TECHNOLOGY:

               When we talk about the conventional IC engine, the combustion/ burning of charge (air+fuel) takes place in the combustion chamber. The charge comes in the combustion chamber through the arrangement of the valves.

              In the case of 2-stroke engines, there are no valves, just ports are present. But for 4-stroke engines normally two valves are located at the top of the combustion chamber. i.e. placed in the cylinder head and comes with complete assembly of valves, springs, spring seats, retainers, collets and the steam seals. Generally, one intake and one exhaust valve are placed per cylinder of the engine and hence it is called 2-valve engine.

              If the engine is placed with two intake valves and two exhaust valves then it is called as the 4-valve engine, due to total four valves per cylinder.

Advantages of 4-Valve Technology:

             The 4-valve engine is the advanced version of the 2-vlave engine. Due to the 4-valve technology, engine breathing can be improved dramatically.

              In the 4-valve engine, more charge is allowed to enter the combustion chamber than the conventional 2-valve engine. Because in 4-valve technology more area can be used for breathing. i.e. two smaller intake valves and two smaller exhaust valves can cover large area than single intake and exhaust valve.

                 Suppose, a 2-valve engine with 50 mm bore diameter and has intake valve with 26 mm diameter and the exhaust valve with 16 mm diameter. Then area for intake of charge (Breath-in) is 530.92 mm² and area for exhaust (Breath-out) is 201.06 mm².

         

                      Now, take one 4-valve engine with same bore diameter and the intake valve with 20 mm diameter and the exhaust valves with 12 mm diameter. Then area for intake of charge is 628.31 mm² and area for exhaust is 226.19 mm².

                   From the above example, you can easily compare the breathing area. obviously, in 4-valve engines, it is found more and so that performance and efficiency are more in those engines due to enhanced breathing process. It also improves fuel economy.

                  The 4-vlave engines can deal with high revs. (rpm) easier than those conventional 2-valve engines by giving much faster throttle response and provides better pick up and power throughout the running. Faster evacuation of exhaust gasses from the combustion chamber takes place and also low emissions are generated by those engines.

                  Another advantage is you can manufacture smaller and lighter valves and no load on single valve only. 

E.g. Pulsar NS 200, Apache 200 4V