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MMT (Methylcyclopentadienylmanganese tricarbonyl) revisited: EPA's conclusions. The effects of MMT on exhaust emissions

Conference · · SAE Passenger Car Meet. Pap.; (United States)
OSTI ID:6538451
Statistical analysis carried out by EPA of data on MMT use collected in 50,000 mi fleet studies by various automobile manufacturers and related firms indicated that Ethyl Corp.'s MMT antiknock additive very probably affects oxygen sensor performance adversely, which leads to increased hydrocarbon (HC) and CO emissions in three-way-catalyst systems. The so-called ''catalyst-enhancement'' effects, for which the supporting data are tenuous, is at best a weak effect that does not overcome the negative effect of MMT on engine-out emissions. The absence of an adverse effect on combustion-chamber deposits due to MMT use has not been established; rather, the few data available suggest that MMT has a strong effect on combustion-chamber deposits, which in turn, increase the engine-out HC emissions. No direct (instantaneous) effect of MMT on fuel economy was perceptible, but automobile manufacturers indicate that if engine-out HC deposit increases due to MMT use require engine recalibration, some fuel economy penalty could occur. Indications of an increasing potential for catalyst plugging with long MMT use could necessitate increasing the MMT concentration (as manganese) to 0.0625 g/gal fuel. No consistent adverse effects on CO or NOxi emissions were noted.
Research Organization:
EPA
OSTI ID:
6538451
Report Number(s):
CONF-7906132-
Conference Information:
Journal Name: SAE Passenger Car Meet. Pap.; (United States) Journal Volume: 790707
Country of Publication:
United States
Language:
English