Three-dimensional energetic and exergetic analysis of the injection orientation of DI diesel engine under different engine speeds

Three-dimensional (3-D) computational code was implemented to solve conservation equations based on finite volume method as to simulate 1.8 L Ford diesel engine. Velocity and pressure of each computational cell is achieved by SIMPLE (semi-implicit method for pressure-linked equations) algorithm. For the exergetic aspect, the initial condition is set at 0.1 MPa and 300 K. The engine modeling is performed with 130 degrees, 140 degrees, and 150 degrees with respect to x-axis under 1500 and 2500 rpm engine speeds. The results, however, indicate better air/fuel mixture (near stoichiometric equivalence ratio) for 130 degrees of injection angle, albeit smaller spray droplets (lower sauter mean diameter) were introduced with 140 degrees. It is seen that higher soot and NOx mass fraction is attributed to 1500 rpm engine speed. The highest NOx and soot are exhausted at 130 degrees and 150 degrees of injection, respectively. Second law efficiency was calculated for different spray angle and engine speed schemes such that 36.62%, 30.2%, and 32.07% are associated with 130 degrees, 140 degrees, and 150 degrees of injection angle under 1500 rpm, respectively. In terms of engine performance, that is, indicated mean effective pressure, indicated specific fuel consumption, and temperature, the best performance metrics are of 130 degrees equal to 15.4 bar, 0.3856 kg/kW-h, and 2074.97 K under 1500 rpm, respectively. Instant irreversibility rate is the highest amount with peak value of 17.48 J/deg for 130 deg-1500 rpm, while 140 degrees shows higher mean irreversibility rate over crank angle (CA) period.