Experimental Study of Influence of Gasoline Fuel with MMT on Aging Performance of Three-Way Catalyst
The octane enhancing fuel additive Methylcyclopentadienyl Manganese Tricarbonyl (MMT) is widely used in China to meet market demand for octane in the unleaded gasoline pool, as the use of gasoline of the appropriate octane level is critical to obtaining o
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Abstract The octane enhancing fuel additive Methylcyclopentadienyl Manganese Tricarbonyl (MMT) is widely used in China to meet market demand for octane in the unleaded gasoline pool, as the use of gasoline of the appropriate octane level is critical to obtaining optimal vehicle fuel economy. The impact of combustion products resulting from the use of MMT-containing gasoline on vehicle emissions control components has long been debated. In order to better understand this issue, a fundamental research program was undertaken to investigate the interactions of combustion products from MMT-containing gasoline with high cell density (600 cpsi) catalysts during severe catalyst operating conditions typical of those used to accelerate catalyst aging for the vehicle durability demonstration process. The paper reports on tests conducted to evaluate the influence of engine running condition, the absence or presence of MMT (at 18 mg Mn/l), and the impact of catalyst inlet temperatures on deposition phenomena occurring at the catalyst face that can lead to plugging. Additionally, a 1000 h test based upon the Type V durability procedure was conducted using MMT-containing gasoline (also at 18 mg Mn/l) to evaluate the impact of the additive under longer term exposure conditions more representative of those dynamic mode operation encountered during typical real-world vehicle operation. Results were consistent with the conclusion that catalyst backpressure was influenced primarily by the test cycle condition, as backpressure increase was only observed during continuous long term exposure of catalysts to MMT-containing fuel at the most severe catalyst inlet temperatures (820 C) under steady-state operating conditions. Backpressure
F2012-A03-024 S. Shuai (&) Y. Wang J. Chen J. Xiao State Key Laboratory of Automotive Safety and Energy, Tsinghua University, Beijing, China e-mail: [email protected]
SAE-China and FISITA (eds.), Proceedings of the FISITA 2012 World Automotive Congress, Lecture Notes in Electrical Engineering 189, DOI: 10.1007/978-3-642-33841-0_44, Springer-Verlag Berlin Heidelberg 2013
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increase was not obviously observed under dynamic operating conditions regardless of the MMT concentration or temperature. Keywords MMT Backpressure
Three-way catalyst Catalyst plugging Driving cycle
1 Introduction Methylcyclopentadienyl Manganese Tricarbonyl (MMT) is primarily used as a fuel additive to improve gasoline anti-knock properties by moderating the rate of combustion reactions that lead to detonation, which maintains the rate of combustion reactions to within the normal operating range. During combustion, MMT decomposes into manganese oxide particles that convert peroxides from the oxidation of n-alkanes into aldehydes and ketones. By inhibiting branch reactions in the flame front and interrupting the reaction chain, the ignition induction period is prolonged, the rate of energy release moderated and the anti-knock properties of the fuel improved [1, 2]. Vehicles designed
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