Mitigating Carbon Deposits in Air Compressors 2003-01-3439
Carbon deposits in air compressors can build up and restrict the air delivery to vehicle brake systems. Field experience has shown that carbon deposits are excessive in some high stress applications. A study was conducted to understand the variables that affect carbon deposits, with the intent of identifying application changes that mitigate excessive build up.
Oil passing in air compressors is a normal byproduct of the piston, ring and bore lubrication process. The oil in the discharge air is oxidized to form carbon deposits if there is sufficient heat. For the purposes of this study, the compressor is modeled as a chemical reactor. The formation of carbon can be minimized by diminishing both oil passing and discharge air temperature, which contribute to oxidation and deposits.
Lab data demonstrates that inlet pressure and rotational speed have the largest impact on carbon, while inlet air humidity, oil composition, and coolant flow (above zero) have minimal impact. Field data demonstrates that turbo charging the compressor inlet reduces duty cycle, and lowering the brake system pressure reduces discharge temperature, thereby minimizing the contributing factors to carbon formation.