Skip to main content

Interferrance angle in diesel engine exhaust valve

  • The interference angle is the angle between the valve seat and the mushroom head of the valve which sits on the valve seat i.e. the difference between the angle of contact of the valve and the valve seat. This angle is required to have the proper contact of the valve and the valve seat when the valve has attained the running temperature. This angle is about ½ degree. 
  • It gives the inner contact to the valve so that when the valve attains the working temperature it expands and have a proper full contact with the valve seat thus preventing any valve leakage. 
  • At the same time, it also helps in sitting the valve quickly. The main reason for the interference angle is to sit the valve and valve seat accurately when they have attained the working temperature
  • The interference angle is provided for the better sitting of the valve and the valve seat. It has nothing to do with the rotation of the valve or the breakup of the seat deposits because the breakup of the seat deposits is carried out with the help of rotation of the valve. Hence it does not have any connection with the interference angle. 
  • Due of the interference angle, the sitting will be proper and because of the proper sitting of the valve and the valve seat, whatever deposits are formed will get crushed and get removed when the valve rotates over the valve seat due to the valve rotor.

Comments

Popular posts from this blog

Differences between MC/MC-C and ME/ME-C engines

The electrohydraulic control mechanisms of the ME engine replace the following components of the conventional MC engine: Chain drive for camshaft Camshaft with fuel cams, exhaust cams and indicator cams Fuel pump actuating gear, including roller guides and reversing mechanism Conventional fuel pressure booster and VIT system Exhaust valve actuating gear and roller guides Engine driven starting air distributor Electronic governor with actuator Regulating shaft Engine side control console Mechanical cylinder lubricators. The Engine Control System of the ME engine comprises: Control units Hydraulic power supply unit Hydraulic cylinder units, including: Electronically controlled fuel injection, and Electronically controlled exhaust valve activation Electronically controlled starting air valves Electronically controlled auxiliary blowers Integrated electronic governor functions Tacho system Electronically controlled Alpha lubricators

Why is a man hole door elliptical in shape?

Any opening in a pressure vessel is kept to a minimum and for a man entry an elliptical hole  is lesser in size than the corresponding circular hole. More over it is prime concern to have a  smoothed generous radius at the corners to eliminate stress concentration. Hence other  geometrical shapes like rectangle and square are ruled out.  To compensate for the loss of material in the shell due to opening, a doubler ring has to be  provided around the opening. The thickness of the ring depends on the axis length along the  dirrection in which the stresses are maximum and the thickness of the shell. It is important to  align the minor axis along the length of the vessel, as the stress in this direction is  maximum. Longitudinal stress: Pd/2t where P= pressure inside the vessel, d= diameter of the arc, t=  thickness of the shell plating  Circumferential stress: Pd/4t  More over a considerable material and weight saving is achieved as minor is along the  direction of maximum stress.

Shell Expansion Plan

It is a two dimensional drawing of a three dimensional surface of the ship’s hull form. This plan is very useful for the following information:It is used for marking the location of a hull Damage on this plan by identifying the strake number , letter and frame number so that the exact location of the damage and also suggested repairs are marked in a localised copy. The shell expansion can be used for finding areas of painting surfaces such as topside, boot topping and bottom areas by applying Simpsons rules directly.  In the shell expansion the vertical scale used is different from the horizontal scale and a suitable adjustment has to be made when calculating areas. This becomes useful in solving disputes concerning areas of preparation and painting. It gives information on the thickness of the original strake which is indicated by the number in the circle shown in the strake.  The quality of steel used is also shown by letters A,B,D E and AH, BH,DH, EH.