Effect of Burn Duration and Injection Timing on Diesel Engine Performance

Abstract

Setting ignition timing, so that the spark is initiated before top-dead-center, is necessary because of the time delay before the explosion reaches maximum force. Purpose is to ensure the piston has begun its downward (power) stroke as the expanding gases reaches its maximum pressure, allowing development of peak pressure and extraction of maximum amount of work from the expanding gases. An engine model obtained from literature was used in this study. The original concept was retained and extensive analyses was carried out by varying in turn the ignition timing before top dead center (bTDC) and after top dead center (aTDC) to values (-40⁰ to 30⁰)and burn duration of charges (-40⁰ to 50⁰) while keeping other parameters constant and measuring the engine performance, in terms of Indicated Mean Effective Pressure (IMEP), Thermal Efficiency (eta), and Emission rate. By the present study it is concluded that retarded ignition timing was beneficial until 40⁰bTDC beyond which it is unfavorable. It is also observed that sufficiently retarded ignition timing goes well with extended combustion duration of 50⁰.