Numerical investigation of the effects of dwell time duration in a two‐stage injection scheme on exergy terms in an IDI diesel engine by three‐dimensional modeling

Abstract

Dwell duration of multiple-injection scheme is an important parameter, which makes it possible to shift the tradeoff curve between soot and NOx closer to the origin. In this investigation, therefore, energy and exergy analyses are carried out for various two-step injection schemes in which 25% of the total fuel is injected during the second pulse and the dwell time is increased from 5°CA (crank angle) to 30°CA by 5°CA increments. The calculations are performed for a Lister 8.1 indirect injection (IDI) diesel engine at full load operation. The energy analysis for these schemes is performed during a closed cycle by using a three-dimensional CFD code. The cylinder pressure results for the baseline engine are compared with the corresponding experimental data and they show good agreement. For the exergy analysis, an in-house computational code has been developed, which uses the results of energy analysis in various cases. With crank angle positions and dwell durations set for different injection schemes, various rates of exergy are calculated and the cumulative exergy components are identified separately. The results show that the values of work exergy and exergy efficiency decrease when the dwell duration is changed from 5°CA to 30°CA. Also, there is a sharp change in the exergy parameters when the dwell time reaches 25°CA.

Thermodynamic modeling and validation of in‐cylinder flow in diesel engines

“…The ringing intensity parameter is used to distinguish the start of knock phenomenon. Ringing intensity parameter is calculated using Equation (19). This parameter is developed by Eng.…”

“…After solving the governing equations and calculation of the in-cylinder pressure at each time step, the maximum values of pressure rise rate, in-cylinder pressure, and temperature are selected and the ringing intensity is calculated using Equation (19). The higher values of ringing intensity indicate a higher likelihood of diesel knock.…”

“…Fluid motion within combustion chamber affects air–fuel mixture formation and controls both premixed and diffusion combustion processes . Engine geometry , injection pressure , nozzle geometry , injection schedule , and thermophysical properties of fuel are the main parameters that can affect fluid movement in combustion chamber.…”

Exergoeconomic comparison and optimization of organic Rankine cycle, trilateral Rankine cycle and transcritical carbon dioxide cycle for heat recovery of low-temperature geothermal water

“…45 Exergy concept is applied in several studies to investigate the performance of the systems and cycles. 46–50 Although exergy cannot be saved during a process, it is partially or totally lost due to irreversibility in the systems. In this regard, the contribution of all components and their contribution to the total exergy destruction through the system can be separately analyzed and calculated.…”

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

“…Moreover, it was indicated that combustion timing has to be adjusted just before the sharp increase in unburned species losses. Jafarmadar and Zehni carried out exergy analysis in combustion chamber of the IDI diesel engine by three‐dimentional modeling. They investigated dwell time duration effect on exergy terms, which resulted in work exergy and exergy efficiency decrease when dwell time increased from 5 ° to 30 °CA.…”