The feasibility study of single-hydrocarbylbenzene/n-heptane model diesel fuels for diesel characterization

Single-hydrocarbylbenzenes are an important component of diesel. Understanding the mechanism of single-hydrocarbylbenzenes in engine combustion and emissions is of great significance in the construction and development of model diesel fuels. In this work, we used n-heptane as a representative components of alkanes, and toluene, n-butylbenzene and 1,2, 4-trimethylbenzene as the representative components of aromatic hydrocarbons and studied the effects of toluene/n-heptane, n-butylbenzene/n-heptane, and 1,2,4-trimethylbenzene/n-heptane blend fuels on the combustions and emissions performance of an engine. The test fuels include pure diesel (D100) and other six single-hydrocarbylbenzene/n-heptane blends (toluene, n-butylbenzene and 1,2,4-trimethylbenzene (T20, BBZ20, TMB20 and T30, BBZ30, TMB30) which were added to n-heptane at volume ratios of 20% and 30%). The experimental results showed that the peak IP increased, and CA50 advanced after the addition of single-hydrocarbylbenzenes. The IP, HRR, ID, and CA50 curves of BBZ20 were the most consistent with those of D100. Moreover, the soot emissions of single-hydrocarbylbenzene blended fuels were low, and the NOx, CO, and THC emissions were higher than those of D100. At EGR < 20%, the difference between NOx emissions of D100 and BBZ or TMB was within 2.6%. Under all EGR rates, the soot emissions of BBZ20 were the closest to those of D100 (especially when the EGR rate is 40%, the difference in soot emissions between BBZ20 and D100 is only 57.8%), and the CO emissions of TMB20 closest to those of D100 (the range of difference is 5-13.3%).

Automated summary

The addition of single-hydrocarbylbenzenes improved engine combustion performance and reduced soot emissions, but increased NOx, CO, and THC emissions. Among the blends, n-butylbenzene/n-heptane showed the performance closest to pure diesel in terms of combustion and emissions.