کد مقاله کد نشریه سال انتشار مقاله انگلیسی نسخه تمام متن
1733864 1016147 2012 7 صفحه PDF دانلود رایگان
عنوان انگلیسی مقاله ISI
Second law analysis of a low temperature combustion diesel engine: Effect of injection timing and exhaust gas recirculation
موضوعات مرتبط
مهندسی و علوم پایه مهندسی انرژی انرژی (عمومی)
پیش نمایش صفحه اول مقاله
Second law analysis of a low temperature combustion diesel engine: Effect of injection timing and exhaust gas recirculation
چکیده انگلیسی

For diesel engines, low temperature combustion (LTC) with a high level of EGR and late injection becomes attractive because of its potential of simultaneous reduction of nitrogen oxides (NOx) and particulate matter (PM) emissions. However, detailed thermodynamic evaluations including second law analysis of the LTC are few. The current work employed an engine cycle simulation incorporating the second law of thermodynamics to evaluate the energy and exergy distribution of various processes in a low temperature combustion diesel engine. After validation with experimental data at eight operating conditions including four different EGR levels and two different injection timings, the model was used to evaluate the effect of EGR level and injection timing on the first and second law parameters. As EGR was increased, intake temperature and equivalence ratio increased. Results showed that for the case at 0% EGR level with conventional injection timing, about 30% of the fuel exergy was destructed during combustion processes, and as EGR level increased to 45% (intake temperature and equivalence ratio also increased), the combustion destructed exergy decreased to 20% of the fuel exergy. This was largely due to the related combustion temperature increase. For both conventional (−6.5° aTDC) and late (1.5° aTDC) injection timings, the percentage of exergy transfer through flows increases as EGR increases, which is attributed to the retarded ignition by increasing EGR. Other parameters such as energy and exergy transfer due to heat transfer, blow-by, and unburned fuel also were determined as a function of EGR level and injection timing.


► Exergy destruction during combustion decreased as intake temperature increased.
► Both conventional and late injection timings (LTC cases) were examined.
► For conventional injection timings, the combustion efficiency remains constant as EGR increases.
► For late injections and high EGR, combustion was incomplete.
► Late injection cases had lower percentage of heat transfer exergy.

ناشر
Database: Elsevier - ScienceDirect (ساینس دایرکت)
Journal: Energy - Volume 38, Issue 1, February 2012, Pages 78–84
نویسندگان
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