نوع مقاله: پژوهشی

نویسندگان

1 استادیار دانشگاه آیت الله العظمی بروجردی، دانشکده فنی مهندسی، گروه مهندسی مکانیک

2 دانشجوی کارشناسی دانشگاه آیت الله بروجردی

چکیده

در تحقیق حاضر، همزمان تاثیرات میزان پیش پاشش سوخت و زمان بندی پاشش بر عملکرد و میزان آلاینده های تولیدی یک موتور اشتعال تراکمی پاشش مستقیم سرعت بالا مورد بررسی قرار گرفته است. برای این منظور از الگوی اصلاح شده اشتعال پیوسته گسترش یافته سه ناحیه ایی بهره گرفته شده است. در مرحله اول، نتایج بدست آمده از شبیه سازی موتور با نتایج تجربی موتور پایه مورد مقایسه قرار گرفته است و تطابق مناسبی از نظر فشار، آهنگ رهایی گرما و درجه حرارت درون استوانه و همچنین میزان آلاینده های تولیدی موتور مشاهده شده است. در مرحله بعد، 9 راهبرد متفاوت از فرآیند پاشش سوخت بر اساس دو متغیر اصلی (وقفه های بین پیش پاشش و پاشش اصلی و همچنین میزان سوخت پاشیده شده در هر مرحله) مورد بررسی قرار گرفته است. نتایج این تحقیق نشان می دهد که میزان و زمانبندی پیش پاشش سوخت تاثیر بسیار عمده ای بر میزان آلاینده های تولیدی و میزان مصرف سوخت ویژه ترمزی دارا می باشد. این نتایج نشان می دهد افشاندن حدود 5/0 میلی گرم سوخت در مرحله پیش پاشش و تعویق زمان پیش پاشش سوخت به میزان 10 درجه میل لنگ (در مقایسه با طرح موتور پایه) سبب کاهش چشمگیر سطح تولید آلاینده های دوده و اکسیدهای نیتروژن می گردد اگرچه در این حالت افزایش میزان مصرف سوخت ویژه ترمزی متوسط (به میزان حدود 5/2 درصد) و همچنین کاهش میانگین فشار موثر داخلی موتور (به میزان حدود 22/2 درصد) بایستی به عنوان دو عامل نامطلوب در نظر گرفته شود.

کلیدواژه‌ها

موضوعات

عنوان مقاله [English]

Investigation of Simultaneous Effects of Pilot Fuel Quantity and Pilot Injection Timing on Emission Formation and Engine Performance in a High Speed Direct Injection (HSDI) Diesel Engine

نویسندگان [English]

  • Raouf Mobasheri 1
  • Mahdi Sediq 2

1 University of Ayatollah Boroujerdi

2 University of Ayatollah Boroujerdi

چکیده [English]

In this research, the simultaneous effects of pilot fuel quantity and pilot injection timing on engine performance and pollutant formation have been studied in a High Speed Direct Injection (HSDI) diesel engine. For this purpose, an improved version of the ECFM-3Z combustion model has been applied. In the first step, the simulated results has been compared with the experimental data and good agreement has been achieved for simulating the in-cylinder pressure, the heat release rate and the amount of pollutant emissions. In the next step, nine different strategies in terms of two main variable parameters (the dwell between pilot injection and main injection as well as the amount of injected fuel in each phase) have been investigated. The results show the amount of pilot injection and its timing have an important effect on the amount of pollutant emissions and the amount of brake specific fuel consumption. These results show by 0.5 mg pilot fuel injection and also the retarding the injection timing by 10 crank angle degree, the amount of NOx and soot emissions have been considerably decreased compared to the baseline case. However, increasing the amount of the brake specific fuel consumption (for about 2.5 %) and decreasing the indicated mean effective pressure (for about 2.2 %) should be considered as two negative factors.

کلیدواژه‌ها [English]

  • High Speed Direct Injection (HSDI) Diesel Engine
  • Combustion Modeling
  • Pilot Injection
  • Soot
  • NOx

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