Abstract: A method and system for controlling an engine that drives a reciprocating compressor, such as the large compressors used for natural gas transmission. A controller receives data from the compressor representing operation conditions, such as load step, suction pressure, and discharge pressure. The controller then calculates engine control parameters, such as air intake and spark timing, based on the compressor data to optimize engine performance and emissions.

Abstract: A method of balancing combustion among cylinders of an internal combustion engine. For each cylinder, a normalized peak firing pressure is calculated as the ratio of its peak firing pressure to its combustion pressure. Each cylinder's normalized peak firing pressure is compared to a target value for normalized peak firing pressure. The fuel flow is adjusted to any cylinder whose normalized peak firing pressure is not substantially equal to the target value.

Abstract: A computer-based system and method detects and specifies valve and ring leaks in reciprocating compressors of the type used in natural gas transmission networks. The system employs a method comprising the following steps. The cylinder pressure is measured as a function of cylinder volume to obtain a measured PV card. A predictive model then calculates a predicted PV card for the subject compressor cylinder without including effects of simulated leaks. The predicted PV card is them compared to the measured PV card. The nature and character of the differences between the measured and predicted PV cards indicates whether a leak in the subject compressor cylinder is a suction valve leak, a discharge valve leak, or a piston ring leak. The predictive model is then iterated with simulations of the indicated leak included until the resulting predicted PV card matches the actual measured PV card for the compressor cylinder.