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A New Strategy to Achieve Radical Combustion Through Exhaust Port Throttling for Two Stroke Engine

Author(s): Saqaff Ahmed Alkaff, Mohamed A. Khan

Journal: International Journal of Engineering ISSN 1985-2312
Volume: 4; Issue: 2; Start page: 139; Date: 2010;
Original page

Keywords: Spark Ignition Combustion | Radical Combustion | Exhaust Port Throttling | Two Stroke Engine | Trial Plates for Throttling Control

ABSTRACT
Radical combustion is a critical condition behind control. In two stroke engine, acondition of radical combustion could be achieved through control of the trappedexhaust gases at a certain condition, might include, the engine load, speed,concentration of the unburned hydrocarbons, their temperature and otheroperational parameters.An earlier work was conducted towards the achievement of the radicalcombustion. The mechanism was made to throttle the opening of the exhaustport at a range of 1% to 8 % [1]. However, several difficulties were faced, mainlywith the control mechanism of throttling. In addition there is a complexity inidentifying the critical conditions at which the radical combustion could beachieved.In this paper, a new strategy was used to control the exhaust port throttling in away to manage the amount of exhaust gases trapped and avoiding thedrawbacks of the throttling mechanism in the earlier work. Three trial plateswere used, one-sixth closed, one-third closed and half closed to throttle theexhaust gases leaving the combustion chamber.Results reveal the possibility of achieving radical combustion, when using theone-sixth closed plate under relatively higher load. Therefore, partial trapping ofthe exhaust gases should be carried, through the restriction of the opening of theexhaust port not to exceed 15% of the port exit area. However, it is moreinteresting, that throttling of the exhaust gases of the two stroke engine haveclear influence on the quality and stability of the combustion and hence its directeffect on the fuel consumption and the rate of pollutants expelled to theenvironment.