Skip to main content

Lambda controller

The purpose with the lambda controller is to prevent injection of more fuel in the combustion chamber of an auxiliary engine on the ship, than can be burned during a momentary load increase. This is carried out by controlling the relation between the fuel index and the charge air pressure. The Lambda controller is also used as stop cylinder.

Advantages of Lambda Controller

The lambda controller has the following advantages:
  1. Reduction of visible smoke in case of sudden momentary load increases on auxiliary engines.
  2. Improved load ability.
  3. Less fouling of the engine’s exhaust gas ways.
  4. Limitation of fuel oil index during starting procedure.

Principle of Lambda Controller


In case of a momentary load increase, the regulating device will increase the index on the injection pumps and hereby the regulator arm (1) is turned, the switch (2) will touch the piston arm (3) and be pushedb downwards, whereby the electrical circuit will be closed.
Thus the solenoid valve (4) opens. This valve is supplied with compressed air and the same is supplied to assist the turbocharger. When this jet system is activated, the turbocharger accelerates and increases the charge air pressure, thereby pressing the piston (3) backwards in the lambda cylinder (5). When the lambda ratio is satisfactory, the jet system will be deactivated. At a 50% load change the system will be activated for about 3-8 seconds.
If the system is activated more than 10 seconds, the solenoid valve will be shut off and there will be a remote signal alarm for “jet system failure”.

Fuel Oil Limiting During Start Procedure

During the start procedure the lambda controller is used as an index limiter. Hereby heavy smoke formation is prevented during start procedure and further the regulating device cannot over-react. The jet system is blocked during the starting procedure until the engine has reached about 110 RPM.

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

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.

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.