STN Blogs School Bus Bay The Case of the Run-Away Diesel Engine
The Case of the Run-Away Diesel Engine PDF Print E-mail
Written by Ryan Gray   
Wednesday, 13 April 2011 11:26

The moral of the Closed Crankcase Filter story could be to ensure proper installation to keep the engine from "running away."

Jack Coxen, the transportation supervisor at Brewster CSD southeast of Poughkeepsie, N.Y., and not far from the Connecticut border, and his staff were having difficulties with a 2006 IC FE Series with a 466 E engine that was displaying spikes in the engine rpm, otherwise known as a run away. The school district had received a grant to have a vendor install a CCV system, and that's when the problems started.

The rpm ran until the technicians disconnected the computer, and there were clouds of smoke that led the team to believe there was also engine damage. Coxen was curious if other operators were having similar experiences, so he posted an item in the "Tech Net" group on STNSOCiAL. Responses from other users indicated Coxen might be experiencing anything from low oil levels to dirty turbo hoses to dirty air filters. But none of those issues were of the root problem, in this case.

So we turned to STN Contributing Editor Robert Pudlewski, the retired vice president of fleet operations for Laidlaw and then First Student. Here's what he suggested:

“When compression ignition diesel engines have an incident like [this one],it is usually due to the crankcase capacity increasing due to being overfull or fuel dilution, providing the engine with an uncontrolled fuel supply, which bypasses any governor or throttle control, thereby allowing the engine to run passed max RPM sometimes leading to engine failure before the fuel source is used up," Pudlewski said. "This event is very difficult to control since engine power or combustion relies on three elements: air, fuel and ignition. The only way to shut a run-away down is to take away one of those elements. Closed Crankcase Ventilating Systems, when installed properly, will not cause the run-away; however, if the crankcase becomes overfull oil could be sucked into the CCV filter.”

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Last Updated on Thursday, 14 April 2011 06:15