MID-LEVEL ETHANOL BLENDS CATALYST DURABILITY STUDY

CRC Project Nos. E-87-1, E-87-2

Leader:      C. Jones
                  B. West

Scope and Objective

The purpose of the study is to investigate the effects of ethanol-blended fuel on open loop air-fuel ratio and catalyst and oxygen sensor temperature.  When a vehicle engine is operated at heavy loads, the control system will enrich the mixture to cool it and protect the catalyst from overheating.  A switching type oxygen sensor will not operate in the rich environment and the control system will lose feedback from the sensor and go to “open-loop” operation. If the enrichment calculation does not take the possibility of higher ethanol in the fuel into account, then the calculation may be in error and the catalyst protection could be compromised.

The objectives of E-87-1 are to procure and test a small fleet (25 vehicles) of U.S. and California certified vehicles to determine whether the fuel ethanol content affects the combustion stoichiometry, catalyst and oxygen sensor temperature when the vehicle is operated in catalyst protection mode.  Four fuels will be used in the project, defined here by their ethanol percent volume content: E0, E10, E15, and E20. This program will serve as a screening study to identify vehicle types (make, model, model year) of interest for the main study, E-87-2, with an objective to determine the effects of intermediate-level ethanol blends on catalyst durability and exhaust emissions. In the main study, 8 of each 10 vehicle types (80 vehicles overall) will be aged to 50,000 miles or full useful life, whichever is greater, with emissions measurements performed at every 25,000 miles.

Current Status and Future

The Transportation Research Center was selected as the contractor for the screening study through a competitive solicitation awarded by CRC.  DOE/ORNL  and DOE/NREL are sharing the results of their pilot studies operating in parallel to E-87-1, and both national laboratories are represented on the CRC E-87 Project Panel.  The screening study testing is in process, with reporting in late 2008.

CRC Emissions Committee members were represented on an advisory panel for the DOE/ORNL contractor selection process for E-87-2, “Catalyst Screening and Durability Study for Intermediate Ethanol Blends.” Southwest Research Institute (SwRI) was selected as the contractor for the main study through a competitive solicitation awarded by DOE/ORNL.  The main study will start in 2008 and continue through 2009.

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