Search Results

Oil carryover is present in all pneumatic systems where the compressed air is generated by oil lubricated compressors. With the increased use of electronic and small orifice components on trucks and coaches, the problem of contamination and failure related to oil carryover in the compressed air system has increased. Even though the rate of oil carryover out of the compressor has improved over recent years, problems persist. This paper will describe how the oil is transported out of the compressor, the various states oil is generated including vapor pressure profiles and size distribution of the condensed aerosols. Also reviewed is the oil removal effectiveness of various components downstream of the compressor. A model of oil liquefaction from vapor and aerosol states will be presented. The effect of liquefied oil combined with other contaminates in the pneumatic system and various design criteria for downstream equipment will be discussed.

The paper details opportunities for electronic control of the pneumatic charging system of an air braked vehicle. Electronic control of the charging and drying functions can result in increased fuel efficiency and improved air quality. Control functions can be used to identify and warn of in-service issues, provide prioritized system charging for faster drive-away, and signal required preventative maintenance. The first portion of the paper describes current industry practice, as well as common issues that can result from those practices. This is followed by presentation of areas of improvement, where specialized control features result in energy savings, air quality increases and maintenance/downtime savings. This portion will focus on adaptive control of components used today, and will briefly discuss opportunities for the next generation of charging system devices. The final section of the paper presents the control logic and vehicle interface allowing for system integration.