Autobalance System Developed For Legacy Slow Speed Integral Engines

An automatic, continuous engine pressure balancing system has been installed on a Cooper-Bessemer 10V-250 on the Williams Gas Pipeline (WGP) system. The autobalance system uses permanently installed pressure monitoring that provides pressure information to a continuous feedback control system.

This system uses an electronic fuel balancing valve for fine tuning the fuel delivery to each cylinder to achieve near perfect balance for all operating conditions of the unit.

WGP operates 41 compressor stations from South Texas to New Jersey. Currently 125 out of a total of 307 reciprocating engine-driven compressors in those stations are monitored locally and remotely through an advanced continuous pressure monitoring and diagnostic system. This continuous pressure monitoring system utilizes crankshaft-referenced dynamic pressure measurement and advanced automated software analysis of power cylinders and compressor cylinder ends to accurately and reliably detect malfunctions, provide easily understood diagnostic messaging, and enable unit-to-unit economic performance comparisons over the WGP wide area network (WAN).

Today, the company’s engines are operating in a different era than when they were first installed 50 plus years ago. In the beginning, most of the pipeline industry had operators in the compressor buildings 24 hours a day, 7 days a week, and 365 days out of the year collecting readings and watching over the equipment. Detonation is a way the engine “communicates” that it has a problem and is in need of attention. When an engine began to detonate, the operator would balance the engine, reduce the load, or make other operating corrections to eliminate the detonation. Ultimately this may have led to stopping the engine. Today, automation is in control of operating the engines, most if not all of the operators are gone and the majority of the compressor stations are unattended. For the remaining WGP reciprocating engine fleet without continuous pressure monitoring we have no way of knowing if the engines are detonating unless someone is in the building.

Project Development
WGP has historically determined that the peak-firing pressure (PFP) method provides the best measure of engine balance. There are two basic requirements for proper peak-firing pressure balance: accurate peak-firing pressure and control of fuel delivery system to each cylinder.

WGP and Windrock recognized that the accurate peak-firing pressure provided by the power cylinder continuous pressure monitoring systems would satisfy the first requirement. With an operating history of approximately five years, the continuous pressure monitoring power cylinder pressure transducers have demonstrated good reliability and the online calibration capability has maintained the required accuracy.

Since accurate peak-firing pressure available from the Windrock continuous pressure monitoring system would satisfy the first requirement of this method of engine balance, the two companies agreed to participate in a developmental project which involved power cylinder autobalancing of a legacy two-cycle engine. The primary goal of this project would be the development of an electronic replacement for the manual balancing valve to satisfy the second balance requirement. Kiene Diesel was selected to provide expertise in designing and producing the electronically controlled balancing valve.