2020年11月25日 · In this article, we will have a look at the different types of piston rings used in marine engines. The compression rings provide sealing above the piston and prevent the gas leakage from the combustion side. The compression rings are located in the first grooves of the piston. However, this may differ according to the design of the engine.

New engines will be fitted with CPR ring packs featuring high-type rings with cermet-coating on the top ring and alu-coating as the running-in coating on all three rings. All three rings will be produced with chromium on the lower face for improved piston ring groove lifetime and will also have gas tight (GT) double S-locks. The two up-

By introducing the controlled pressure relief (CPR) piston ring design with gas tight finger locks on all piston rings, the gas leakage through the piston ring pack is controlled by controlled leakage (CL) grooves. Fitting a gastight piston ring in the third ring position makes the complete piston ring pack gastight. Thereby

As shown in Figure 6, CPR ring allows almost constant pressure drop across the ring irrespective of the ring and liner wear. Nodular cast iron ring provides sufficient strength and...

2020年1月7日 · CPR ring: The controlled pressure relief ring is fitted in the MAN piston as a top ring. The CPR ring has “S” shaped butt joint with six controlled pressure relief grooves milled across the face. Measure the radial depth of the grooves butt clearance at the S joint.

Upper ring designed with controlled pressure relief *(CPR) alu-coated chrome. The rest of the rings are alu-coated. Always supplied according to latest design. Upper ring : Height reduced by 0.1mm (reduced risk of sticking). Position of relief grooves has been modified (grooves moved away from the stress area).

2009年1月1日 · The present design of piston ring packs and cylinder liners represents a development driven by environmental regulations, reliability and operating costs of two-stroke engines.The use of...

The document summarizes a service letter regarding a new piston ring standard for large bore MAN B&W two-stroke marine diesel engines. The new standard features a CPR (Coated Piston Ring) pack configuration with high-type rings coated with cermet and aluminum.

Being an internal combustion engine the pistons are equipped with piston rings in order to seal the high pressure gas in the combustion chamber from the low pressure scavenging air box. Today four piston rings are fitted in the piston ring pack. Each ring allows for a certain amount of leakage through either grooves or end gap, see Figure 1.

To eliminate the negative influence from worn-out (CL) grooves, we have tested an alternative ring type to replace the CPR-CL ring. This new ring type is called CPR-POP (Port-On-Plane). The main configuration with the double S-lock and gas relief grooves remains unchanged.