Here, I have explained piston cooling of main engine(Sulzer engine). The working piston consists basically of:
- Piston skirt is directly screw fastened to the piston rod.
- Piston crown and piston rod are joined by ten elastic bolts 9(indicated by 1 in the figure).
- The oil cooling components and piston rings (indicated by 2 in the figure).
- Piston rod (indicated by 5 in the figure)
- Piston crown (indicated by 1 in the figure)
- Piston skirt (indicated by 3 in the figure)
- Piston rod is fastened to crosshead pin (indicated by 1 in the figure) in a particular position.
- A compression shim is fitted between them (piston rod base and crosshead pin), its thickness being adapted to the compression ratio.
Fig.: Piston cooling of Sulzer engine
Key to above figure:
1- Piston crown
2- Top piston rings
3- Piston skirt
4- Spray plate
5- Piston rod
6- Oil pipe to spray plate
7- Compression shim
8- Crosshead pin
9- Elastic bolt
EN – Inlet slot (groove)
KO – Piston cooling oil
OR- Oil return from working piston
SO- Spray oil
The piston crown is cooled by bearing lubricating oil. The piston cooling oil ’KO’ is fed from crosshead pin into the two inlet slots ’EN’. From here it flows outside the oil pipe 6 (arranged in the piston rod) till spray plate. The cooling oil is sprayed into the cooling bores of the piston crown through nozzles in the spray plate. From there the oil ’OR’ flows through oil pipe into the crosshead pin from where it emerges sideways.