Search Results

An investigation was performed to identify the benefits of cooled exhaust gas recirculation (EGR) when applied to a potential ethanol flexible fuelled vehicle (eFFV) engine. The fuels investigated in this study represented the range a flex-fuel engine may be exposed to in the United States; from 85% ethanol/gasoline blend (E85) to regular gasoline. The test engine was a 2.0-L in-line 4 cylinder that was turbocharged and port fuel injected (PFI). Ethanol blended fuels, including E85, have a higher octane rating and produce lower exhaust temperatures compared to gasoline. EGR has also been shown to decrease engine knock tendency and decrease exhaust temperatures. A natural progression was to take advantage of the superior combustion characteristics of E85 (i.e. increase compression ratio), and then employ EGR to maintain performance with gasoline. When EGR alone could not provide the necessary knock margin, hydrogen (H2) was added to simulate an onboard fuel reformer.

In the last several years, there have been a number of independently run research programs evaluating the effects of electrically-heated catalysts (EHCs) on exhaust emissions from gasoline-fueled light-duty passenger vehicles. This paper “pools” data from several of these programs to determine the fleet effect by statistical methods. Evaluation of the overall data set from the eight car fleet indicates a very large reduction in total hydrocarbon (THC) and carbon monoxide (CO) but an accompanying increase (appreciably smaller in magnitude) in oxides of nitrogen (NOx). A follow-up program is under way to examine fuel sensitivity issues.