Experimental and Theoretical Investigation of the Effects of Gasoline Blends on Single-Cylinder Diesel Engine Performance and Exhaust Emissions

Abstract

The present study investigates experimentally and theoretically the effects of using of gasoline-diesel fuel blends on single-cylinder diesel engine performance and exhaust emissions. The study consists of two parts: (i) Experimental study: The effects of using of different gasoline-diesel fuel blends have been investigated experimentally and compared in a single-cylinder diesel engine. In this part, the effects of 2-10% gasoline blends have been investigated experimentally in a single-cylinder diesel engine at the speeds of 900-1600 rpm and at the selected compression ratios of 18-23. (ii) Theoretical study: A computer program has been developed for the prediction of diesel engine cycles and engine characteristics for the cases of neat diesel fuel (NDF) and gasoline-diesel fuel blends. For calculation of the diesel engine cycle, a quasi-dimensional phenomenological combustion model developed by Shahed and then improved by Ottikkutti has been used and modified with new assumptions. After the engine cycle model for NDF and gasoline blends was proven to give correct results by comparing it to experimental and theoretical results, 2-10% gasoline blends have been investigated theoretically for the same experimental engine. In the theoretical studies, ignition delay, combustion duration, pressure and temperature of the cylinder charge, and mole fraction of carbon monoxide (CO) and nitric oxide (NO) concentrations have been calculated. From experimental results, it is determined that brake-effective power output decreases at the levels of 1.5-4% at low engine compression ratios, such as 18, 19, and 20. However, brake-effective power increases 1.5-4% at high compression ratios, such as 21, 22, and 23. Brake-effective efficiency increases at the levels of 2-6%, and brake-specific fuel consumption decreases at the levels of 2-6% at low ratios of gasoline/diesel fuel. It can be said that the ratios of 4-6% are the most favorable percentage interval of gasoline at the selected compression ratios for this engine. Because the cost of gasoline is higher than that of diesel fuel and the decrease in the brake-specific fuel consumption is low, gasoline blends are not economical for this engine at low compression ratios. However, approximately 3% price saving is attained at low blend percentages for high compression ratios. From theoretical results, it is determined that ignition delay increases as the gasoline ratio increases because of the decreasing cetane number (CN) of the mixture. Combustion duration remains approximately constant with an increasing gasoline ratio at low engine speeds, but it decreases at high speeds. The mole fraction of CO and NO concentrations increase with an increasing gasoline/diesel ratio because of increasing combustion temperatures. As the gasoline/diesel ratio increases, the NO concentration and mole fraction of CO of this engine increase at the levels of 7-29 and 15-90%, respectively.

TURBOŞARJLI ÖN YANMA ODALI BİR DİZEL MOTORUNDA BENZİN-DİZEL YAKITI KARIŞIMLARININ KULLANILMASININ MOTOR PERFORMANS PARAMETRELERİ VE NOx EMİSYONU ÜZERİNDEKİ ETKİLERİNİN DENEYSEL İNCELENMESİ

“…Yani bu durumda benzin karışımı ile tutuşma gecikmesinin arttığı söylenebilir. Literatürde de benzeri sonuçlar bulunmuştur [6][7][8][9]. Ayrıca söz konusu şekilden benzin karışımları ile açığa çıkan ısı miktarının arttığı da görülebilir.…”

“…Bununla birlikte; benzin, fumigasyon ve karışım gibi iki farklı yöntemle dizel motorlarında da kullanılabilmektedir ve söz konusu yöntemlerin uygulanması ile motor performans parametrelerinin iyileştiği ve çevre kirliliğinin azaldığı belirlenmiştir [4][5][6][7][8][9]. Benzinin emme kanalında emme havasının içerisine püskürtüldüğü fumigasyon yöntemi ile ilgili Durgun ve Şahin tarafından hem deneysel ve hem de sayısal çalışmalar yapılmıştır [2,4,5].…”

“…Benzinin dizel yakıtına doğrudan karıştırılarak kullanıldığı karışım (benzin-dizel yakıtı karışımı) yöntemi ile ilgili çalışmalar daha sınırlı sayıdadır [6][7][8][9]. Han ve arkadaşları [6], tek silindirli bir dizel motorunda, % 20 ve % 40 BDYK'larının NO x ve is emisyonları üzerindeki etkilerini deneysel olarak incelemişlerdir.…”

Research on the physical property of diesel-gasoline blend fuel

“…Han et al [6] carried out series researches on the combustion and emissions characteristics of a single-cylinder diesel engine using the Diesel-Gasoline Blend Fuel, their research results showed that by employing a proper ratio of diesel to gasoline, the operation range of HCCI engine could be greatly broadened, meanwhile a lower emission level could be achieved. A reduced gas-phase chemical mechanism of "dieseline" was developed by Kokjohn et al [7] , then the mechanism was coupled with the KIVA code to establish the "dieseline" HCCI mode, based on this mode, lots of simulation works about the combustion and emissions characteristics of the "dieseline" engine had been done [8][9][10] .…”

“…Han et al [6] carried out series researches on the combustion and emissions characteristics of a single-cylinder diesel engine using the Diesel-Gasoline Blend Fuel, their research results showed that by employing a proper ratio of diesel to gasoline, the operation range of HCCI engine could be greatly broadened, meanwhile a lower emission level could be achieved. A reduced gas-phase chemical mechanism of "dieseline" was developed by Kokjohn et al [7] , then the mechanism was coupled with the KIVA code to establish the "dieseline" HCCI mode, based on this mode, lots of simulation works about the combustion and emissions characteristics of the "dieseline" engine had been done [8][9][10] .In general, combustion and emission characteristics of ICE are greatly affected by the atomization of fuel sprays. In turn, fuel atomization and evaporation are strongly influenced by fuel properties such as density, surface tension, viscosity et al "Dieseline" is a new blend fuel, research works on its physical properties have rarely been done or published yet, thus it is of significance to establish the database of physical parameters of this new blend fuel.…”