Utilizing dynamic fuel pressure sensor for detecting bearing Spalling and gear pump failure modes in Cummins pressure time (PT) Pumps

Abstract

The objective of this paper is to highlight the results of the fault detection investigation conducted to ascertain the feasibility of exploiting the existing on-board M2/M3 Bradley fuel pressure sensor for the purpose of detecting mechanical bearing spalling and gear pump failure modes of the pressure-time (PT) fuel pump used on the Cummins VTA-903T engine. To investigate this fluid-mechanical cross domain detection approach, a Bradley fuel system test bed was built. Fault tests for four PT pump failure modes were conducted including bearing faults, gear pump fault, idle adjust mis-calibration, and air-fuel control fault. The results of the first two fault tests are summarized in this paper. Due to limited number of pumps available for testing (2), these preliminary findings are not statistically substantiated. With this stated, the findings present a method for investigating the presence of a narrowband frequency-domain-based predictive fault detection capability using the existing pressure sensor installed on the Chassis Modernization and Embedded Diagnostics (CMED) variant Bradley. The test stand based seeded fault analysis was not capable of detecting an 0.080 inch outer raceway bearing spall, but there is preliminary evidence to warrant further study that a nominal 0.001 inch foreign object debris accumulation on the gear teeth of the gear pump might be detectable using a simple kurtosis based calculation using a pressure sensor with a 0-500 Hz dynamic bandwidth.