The performance of two catalyst preparations, styled base and base/noble, were determined employing a simulated mining vehicle loading cycle. Such cycles are characterized by sufficiently high exhaust temperatures to cause auto-regeneration of the filter units when these catalyst preparations are employed. Such loading is exhibited in raining service by some moderate and most high production load-haul-dump vehicles plus some haulage trucks. These preparations were shown to be capable of depressing the nominal, ‘untreated’ steady-state minimum soot ignition temperature of approximately 500°C (932°F), to a range varying from 395°C to 424°C (743°F to 797°F).
Results of gaseous constituent analyses, particulate determinations, polynuclear aromatic hydrocarbon sampling, catalytic sulphur conversion (SO2 to H2SO4) and Ames testing are presented for the two catalyst preparations studied.
In addition, because of concern for the environmental impact of manganese in fuel additives, results of detailed manganese trapping efficiency tests for ceramic diesel particulate filters, are also presented.