How to reverse engine of SULZER and MAN B&W?

HOW TO REVERSE AN ENGINE

• To reverse an engine the engine cycle may require re-timing.

MAN B&W ENGINES

• In old M.A.N engines, the reversing procedure is carri ed out by means of shifting the camshaft axially. For this purpose a separate astern cam is fitted to the camshaft.

         Each astern cam is fitted next to the corresponding ahead cam.

         The whole camshaft can be shifted axially with the help of hydraulic cylinders fitted to the camshaft. The hydraulic oil(sometimes pressurized air) gets pressurized and forces the piston inside the cylinder which moves the entire shaft from ahead to astern or from astern to ahead.

• In M.A.N. B&W MC Engines, These engines have a separate method. In this method instead of shifting the entire camshaft, we are shifting the cam follower rollers to alter the timing. Compressed air from the starting system is used to actuate the pneumatic cylinder and piston which displaces each follower unit.

SULZER ENGINES

• Sulzer engines have lost-motion servomotors on the camshaft. These servomotors are useful to rotate the fuel pump cams to their astern positions. In RTA engines a servomotor is fitted in between a pair of adjacent cams.
  Lost motion is a term which means the timing has been retarded by a certain angle with respect to the new direction of rotation.

(Now all engines are made fully electical and electronic control, therefore no cam, camshaft , fuel pump etc. for example in case of COMMON RAIL FUEL INJECTION. )