Search

The hardness of various types of soot produced by heavy- and light-duty diesel engines of European, Japanese, and North American designs was measured by low-loss electron energy-loss spectroscopy (EELS). No clear general trend can be established that shows heavy-duty diesel engine soot is necessarily harder than light-duty diesel engine soot. The variation in hardness among individual soot particles produced by the same diesel engine can be as large as differences between the hardest soot particles produced by heavy-duty diesel engines and the softest soot particles produced by light-duty diesel engines. There are heavy-duty diesel engines that can produce soot that is softer than that produced by some light-duty diesel engines and vice versa. Nevertheless, the hardness of all types of soot studied is close to the range of hardness of metal engine parts. Thus, the results indicate that soot is hard enough to abrade some metal engine parts.