Search Results

Fuel injection into the negative valve overlap (NVO) period is a common method for controlling combustion phasing in homogeneous charge compression ignition (HCCI) and other forms of advanced combustion. When fuel is injected into O2-deficient NVO conditions, a portion of the fuel can be converted to products containing significant levels of H2 and CO. Additionally, other short chain hydrocarbons are produced by means of thermal cracking, water-gas shift, and partial oxidation reactions. The present study experimentally investigates the fuel reforming chemistry that occurs during NVO. To this end, two very different experimental facilities are utilized and their results are compared. One facility is located at Oak Ridge National Laboratory, which uses a custom research engine cycle developed to isolate the NVO event from main combustion, allowing a steady stream of NVO reformate to be exhausted from the engine and chemically analyzed.

Analytical ferrography was used as a wear measurement tool while implimenting a procedure to calculate the wear particle generation rate and filter efficiency during laboratory diesel engine testing. The engine testing methodology with quantitative ferrography proved to be a sensitive wear measurement technique in detecting a reduction in the wear particle generation rate for a better anti-wear (API SF/CD) oil from that of a baseline API SD/CD oil. Ferrography and spectroscopy were useful as diagnostic tools for the detection and correction of the unexpected circulation of copper contaminant in the lubrication system. A journal bearing failure was detected with qualitative ferrography and verified with an engine teardown while spectroscopy did not detect the bearing failure.