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Secondary Injection in fuel pump and fuel valve

Reopening of the fuel valve after the main injection id terminated is secondary injection . The sudden closing of the injector needle cause a pressure wave to be setup which reflects from the delivery valve back to the injector needle . If the residual pressure and reflected pressure together exceeds the injector lifting pressure , secondary injection takes place.

Why con rods are I sections ?

Con rods during operation are subjected to buckling loads Buckling strength is directly proportional to moment of inertia. So , I section is having maximum area moment and least weight. Hence introduce the vibration of conrod and also reduce side thrust acting on the cylinder. I section can be easily manufactured

Shroud Ring

Shroud ring is a component in turbocharger which forms a part of the inner exhaust gas casing adjacent to the turbine The area around the turbine is always in contact with highly corrosive exhaust gas. If no shroud ring is fitted , the turbine inner casing will be slowly wasted and complete housing to be renewed for repair . Otherwise only shroud ring can be replaced with new one

How piston rings are manufactured ?

Manufactured using Pot casting method , producing a short cylinder of oval cross- section from which the rings are machined in a cam turning lathe. This produces a balanced and homogenous casting around the entire circumference of the ring. The lathe is equipped with an interchangeable copying cam , which controls the cutting tool By changing the shape or ovality of the cam , the circumferential pressure distribution at the ring can be altered

Why air compressor valves are concentric ?

They have a low inertia of moving parts and good flow characteristics. It is highly efficient at higher rotational speed. Concentric valve is compact and a combination of suction and discharge valve , which make it compact and space saving with the lowest possible clearance volume. Plate type suction and discharge valve , whose larger diameter and small lift after the least resistance to the flow of gases