In 1990, Roy Douglas developed an analytical method to calculate the global air-to-fuel ratio of a two-stroke engine from exhaust gas emissions. While this method has considerable application to two-stroke engines, it does not permit the calculation of air-to-fuel ratios for oxygenated fuels. This study proposed modifications to the Roy Douglas method such that it can be applied to oxygenated fuels. The ISO #16183 standard, the modified Spindt method, and the Brettschneider method were used to evaluate the modifications to the Roy Douglas method. In addition, a trapped air-to-fuel ratio, appropriate for two-stroke engines, was also modified to incorporate oxygenated fuels.To validate the modified calculation method, tests were performed using a two-stroke carbureted and two-stroke direct injected marine outboard engine over a five-mode marine test cycle running indolene and low level blends of ethanol and iso-butanol fuels. Results indicate that the modified air-fuel ratio method closely relates to the ISO #16183 standard. The modified Spindt method over-estimated the global air-to-fuel ratio. While the Brettschneider is considered an advancement over the Spindt method, it still provided an over-estimate of the air-to-fuel ratio. Applying a trapped air-to-fuel ratio calculation to the modified Roy Douglas method provided a calculation for trapped air-to-fuel ratio for two-stroke engine operation, which correlated with engine-out CO emissions. The trapped air-to-fuel ratio calculation also provided improvements in air-to-fuel ratio predictions, especially during idle conditions.


    Access

    Check access

    Check availability in my library

    Order at Subito €


    Export, share and cite



    Title :

    Air-to-Fuel Ratio Calculation Methods for Oxygenated Fuels in Two-Stroke Engines


    Additional title:

    Sae Technical Papers


    Contributors:

    Conference:

    SAE 2015 World Congress & Exhibition ; 2015



    Publication date :

    2015-04-14




    Type of media :

    Conference paper


    Type of material :

    Print


    Language :

    English




    Air-to Fuel Ratio Calculation Methods for Oxygenated Fuels in Two-Stroke Engines

    Sevik, James M. / Wallner, Thomas / Miers, Scott et al. | British Library Conference Proceedings | 2015


    Spindt air-fuel ratio method generalization for oxygenated fuels

    Bresenham,D. / Reisel,J. / Neusen,K. et al. | Automotive engineering | 1998


    Spindt Air-Fuel Ratio Method Generalization for Oxygenated Fuels

    Bresenham, Damon / Reisel, John / Neusen, Ken | SAE | 1998


    Oxygenated fuels for clean heavy-duty diesel engines

    Frijters, P.J.M. | Online Contents | 2006


    Oxygenated fuels for clean heavy-duty diesel engines

    Frijters,P.J. / Baert,R.S. / Eindhoven Univ.of Technol.,NL | Automotive engineering | 2006