Page 63 - CARILEC CE Industry Journal_Oct_2019

After a root cause analysis and complete disassembly and Due to the design of this Fuel Delivery Valve, there was
inspection of the fuel pump (Fig. 32), it was revealed that enough fuel being delivered for the cylinder to fire but at
two internal components were not installed during the a reduced pressure. It was also noted that there was a
last pump rebuild. through wall crack in the Delivery Valve Assembly. It is
believed that this crack was caused by high pressure
This detailed inspection revealed that the Fuel Delivery being built up in the pump due to the restricted flow area
Valve Stop and Fuel Delivery Fuel Valve Spring were not to the fuel injector.
installed.

Fig. 31 - Fuel Pump-Picture courtesy of MPR Associates

Case Study #3-Valves Hitting Piston The diesel generator at this station is one of many at this
location that provide power to a Caribbean Island. The
Operations and maintenance personnel identified a engine is a 16 cylinder Sulzer 16ZV40/48 rated at
mechanical “ticking” sound coming from Cylinder L1. The 11,125 BHP. Each cylinder has a 400mm (15.748”)
plant’s peak pressure monitoring also identified cylinder bore and a 480mm (18.989”) stroke and operates at
L1 has having the highest peak pressure at 11% higher 514 rpm. This engine also employs a rotating piston
than the engine average (Fig.32). The increase in crown design.
pressure was noted after a maintenance activity where
the head was removed and reinstalled. As shown in the engine report below (Fig 32.), it should
be noted that even though the peak pressure and
Comprehensive engine analysis was performed which compression pressure were the highest, the peak
determined that the mechanical ticking was occurring just pressure angle was earliest and the exhaust temperature
prior (1 deg.) to Top Dead Center (TDC) on the scavenging was below the engine average. This is caused by the
stroke (Fig. 33). With the piston at or very near TDC on the higher compression pressure (17%) due to the smaller
scavenging stroke is when both the exhaust valves and clearance volume which in turn results in earlier
intake valves are open. As a result of the analysis combustion and a higher peak pressure.
performed, a maintenance activity was performed which
indicated the valves where touching the piston at TDC. It
was also determined that a 1mm shim or spacer was
installed, and not the required 2mm spacer.
CE INDUSTRY Journal 61