Machine Parts

Solid injection system: There are three types of solid injection system a.       Individual system. b.       Distribution system c.        Common rail system.   Fuel Nozzles: 1.       Single Nozzle. 2.       Multi nozzle. 3.       Pintle nozzle. What is Scavenging? It is the method of removing the combustion products during exhaust from the cylinder. Theoritical scavenging process: There are actually three process occurred in scavenging process- a.       Perfect scavenging. b.       Perfect mining.         c.  Short circuiting

Fuel Injection System: There are two fuel injection system- a.       Air injection system b.       Solid injection system. Advantages of air injection system: 1.       Good atomization due to large pressure. 2.       Heavy and viscous fuels can be injected. 3.       Fuel pump is required to develop a small pressure. Disadvantages of air injection system: 1.       Requires a high pressure multi-stage compression. 2.       Separate mechanical linkage is required to operate the fuel value. 3.       Overheating and burning may occur. 4.       Low output pressure. 5.       Sticky of fuel valve may occur.

1.       Meter quantity of fuel as per speed and loads. 2.       Distribute the metered fuel equally among the cylinders. 3.       Inject the fuel as the correct time in the cycle. 4.       Inject the fuel at the correct rate. 5.       Inject the fuel with required spray pattern and atomization demand by the combustion chamber. 6.       Begin and end injection sharply without dribbling of after injection. To   fullfill the all requirement the injection system consist of  1.       Pumping elements. 2.       Metering elements. 3.       Metering controls. 4.       Distribution element. 5.       Timing control.

Stated as follows: a.       The maximum velocity at the throat equals sonic velocity. b.       The maximum pressure at the throat is the critical pressure. c.        Maximum mass flow rate occurs when the throat pressure is maximum. d.       Decreasing the back pressure below the critical pressure does not change the velocity or pressure at the throat or mass flow rate. e.       When the back pressure is lowered below critical value the gas     expands in the divergent part of the nozzle and velocity becomes supersonic.