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If fuels that are more resistant to autoignition are injected near top dead centre in compression ignition engines, they ignite much later than diesel fuel does, and combustion occurs when the fuel and air have had more chance to mix. This helps to reduce nitrogen oxide and smoke emissions. Moreover, this can be achieved at much lower injection pre...
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... recirculation (EGR) to control the NO x emissions. A practical way of reducing the RON would be to blend diesel fuel with gasoline. Such fuel blends have a wide volatility range since they contain high-boiling-point components from the diesel but have lower RONs than that of the gasoline used but have much longer ignition delays than that of the diesel fuel. This work describes the results of running a single-cylinder diesel engine on three such fuel blends. It is important to avoid over-mixing the fuel with oxygen in low-load conditions; the use of lower injection pressures and higher injector flow rates helps to achieve this. At the same time, it is also important to avoid vapour lock in the injection system with high- octane-number fuels which have low boiling points. The wider volatility range of the gasoline–diesel blends might help to achieve these goals. With fuels which have long ignition delays, a lower injection pressure results in better combustion stability and significantly lower HC and CO emissions without compromising the NO x or smoke emissions. The engine could be run on such blends with extremely low smoke and low NO x levels at speeds of up to 4000 r/min and loads (indicated mean effective pressures (IMEP)) of up to 10 bar with an injection pressure of only 400 bar. The smoke level at comparable NO x levels was extremely high with diesel fuel in these conditions, even with an injection pressure of 1100 bar. The engine could also be run at low loads and speeds including near-idle conditions on these blends but with higher HC and CO emissions but much lower NO x emissions and a maximum pressure rise rate (MPRR) compared with those of the diesel fuel. The experiments were performed on a 0.537 l single- cylinder research engine with a compression ratio of 15.9:1. The specifications of the single-cylinder engine are given in Table 1. All experiments were made with coolant and oil temperatures at 90 ° C and the inlet air temperature was kept at 60 ° C. Fuel was injected via a Bosch seven-hole injector, with an injector cone angle of 153 ° , fed by an independent fuel supply rig. The injectors are controlled using an IAV GmbH injection controller to maintain a constant injection pressure, injection timing and IMEP. An external air compressor was used to simulate boosted conditions. When EGR was introduced, the exhaust back pressure was set 0.2 bar higher than the inlet manifold air pressure, and the recirculated gases were cooled using an external cooling circuit to the same temperature as the inlet air, i.e. 60 ° C. The in-cylinder pressure was measured with a water-cooled pressure transducer (Kistler 6041A). The emissions and inlet carbon dioxide (CO 2 ) level were measured using a Horiba MEXA-9500H system, and soot was measured using an AVL 415 smoke meter. After a stabilisation period, the emissions were logged once per second for 60 s and the averages of those 60 recordings are presented in this paper. At the same time, the in-cylinder pressure was recorded for 250 cycles. Two nozzles are used in this study. Nozzle 01 is a standard nozzle with a 0.13 mm orifice diameter for the engine, and nozzle 02 is designed for high-octane- number fuels with a 0.17 mm nominal orifice diameter and higher flow number than that of nozzle 1. Figure 1 shows the flow rates of each nozzle with different injection pressures and durations. Clearly the flow rate changes do not correspond to the external orifice diameters quoted above, which were measured using an electron microscope. Nozzle 02 was made by first laser welding the holes of a duplicate nozzle 01, next drilling the larger hole size and then honing it. There are clearly factors (perhaps cavitation) that affect the discharge coefficient of this nozzle. Otherwise the flow rate would have increased by a factor which is the square of the external nozzle diameters quoted above. The conventional diesel has a lower RON than that of the currently available gasoline fuel. Correspondingly, the currently available gasoline fuel has a lower CN than that of the currently available diesel fuel. A blend of currently available gasoline fuel and diesel fuel yields a fuel composition having both a lower octane number and a lower CN than the corresponding values for indi- vidual gasoline fuel and diesel fuel respectively, which is especially suitable for PPCI engines. The ignition quali- ties of the blended fuels can be varied as needed to meet the requirements of the PPCI engine. A commercial European gasoline fuel and three different blended fuels are used in this study and compared with a standard European diesel fuel. The three blended fuels are GD10 (90 vol % of 95 RON European gasoline and 10 vol % of 56 CN European diesel fuel), GD20 (80 vol % of 95 RON European gasoline and 20 vol % of 56 CN European diesel fuel) and G # D15 (85 vol % of 91 RON US gasoline and 15 vol % of 56 CN European diesel fuel). The volatility characteristics of these fuels are shown in Figure 2, where the volume percentage recov- ered at a given temperature in the ASTM D86 volatility test is plotted against the temperature. The fuel properties are listed in Table 2. The diesel fuel is a commercial low-sulphur European diesel fuel with a CN of 56 with a boiling-point range between 162 ° C and 365 ° C while the boiling-point range of the gasoline fuel is between 46 ° C and 195 ° C. Unfortunately, the RON and the motor octane number (MON) cannot be measured in the Cooperative Fuel Research (CFR TM ) engine for diesel fuel because of its low volatility and the CNs of the gasoline fuels, and the blended fuels are also estimated using equation (6) (CN = 54.6 – 0.42RON) from the paper by Kalghatgi. 13 The fuels had a sufficient amount of lubricity additive (300 ppm of Paradyne R655 from Infineum) to ensure that the lubricity scar size was well within the European specification. It can also be seen from Table 2 that all the fuels have similar gravimetric heats of combustion. The fuel consumption was calculated using the measured exhaust emissions and air consumption rate because there were problems of stability with the fuel flow meter at the low flow rates encountered for the volatile fuels; this is less desirable than direct measurements of the fuel consumption. It is worth noting that, even for GD20, the flash point will be comparable with that of gasoline and it would be safe to carry the fuel in a fuel tank in a car; the vapour mixture above the liquid will be too rich for combustion. However, this might not be the case for higher percentages of diesel fuel in the blend. In the discussion below, all the values for the crank angle (CA) (in degrees) are expressed in relation to the top dead centre (TDC) of the compression stroke, which is zero; the TDC on the exhaust stroke is 360 ° CA. The pressure signals are averaged over 250 cycles, and the HRRs are calculated from the pressure signals and averaged over 250 cycles. Combustion phasing parameters such as the crank angle at which 50% of total heat release has taken place (CA50) are calculated from the integrated average heat release. We shall first consider the low-load case at 1200 r/min. For each fuel and nozzle, the fuelling rate was fixed to obtain an IMEP at a CA50 of 10 ° CA. The start of injection (SOI) is the CA position of the electric signal that marks when the injection starts rather than when the actual fuel flow starts, which might be measured with a needle lift device. Over the SOI range considered, the IMEP varies little for the high-CN fuels and by up to 10% for the low-CN fuels. The emission results are shown as indicated specific values to account for these changes in the IMEP. 1.1 bar; injection pressure, 250 bar. The fuelling rate was fixed to obtain an IMEP of around 4 bar at a CA50 of 10 ° CA for each fuel. Two nozzles are investigated with an injection pressure of 250 bar for gasoline-type fuels and the results are compared with those for diesel fuel by using nozzle 01 with an injection pressure of 650 bar, which is the recommended pressure for diesel fuel in this engine in these operating conditions. The normalized global l value is around 2.6 and the smoke levels were low, with a filter smoke number (FSN) of less than 0.08 for D1 (conventional diesel), which had the highest level compared with others in these conditions. Figure 3 shows CA50 versus the SOI. The combustion delay (CD), which is given by CD = CA50 – SOI, is a reasonably good parameter to help us to understand the fuel effects in this type of PPCI combustion. The fuels GD20 and G # D15 have similar CDs while GD10 shows the longest ignition delay, and also the longest CD, which can be inferred from Figure 3. The longer the value of CD, the more premixed the fuel and air are at the time of the main combustion. For all fuels, combustion starts after the injection is complete in these low-load conditions, but the mixture strengths of the mixture packets where combustion takes place differ because of different ignition delays. When the CD is long, as for fuel GD10, combustion occurs when the fuel and air are better mixed. The overall mixture strength, in mixture packets which burn, will be nearer the global mixture strength which is very lean ( l = 2.6). In contrast, diesel fuel ignites very soon after injection starts and the mixture packets that burn will be comparatively richer. Autoignition will take place in rich mixture packets and produce HRRs and a higher combustion temperature. This results in high NO x emissions in Figure 4. The ignition delays, for high- RON fuels can be reduced by reducing the injection pressure in these operating conditions. 5,14 Presumably this is because of less vigorous mixing, which leads to generally richer mixture packets that ignite earlier. With the CD slightly longer, as for GD20 and G # D15, combustion will start with the mixture packets still rich but nearer the stoichiometric mixture strength, on average, compared ...
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Citations
... A.K. Agarwal et al. cooling effect and the ignition delay [51]. At 3 bar BMEP, higher CHR was obtained at 20 • bTDC θ MI than other θ MI . ...
... HC emissions are formed due to incomplete combustion of hydrocarbon fuel. 60-80 % lower HC emissions were observed in the CDC mode than in the GCI mode [51]. At low engine loads, low combustion temperature produced higher HC emissions than high engine loads. ...
... Significantlylower NOx emissions (20 -80 %) were observed in GCI mode than in the CDC mode (Fig. 13). Similar results were also reported by Won et al. [51]. NOx emissions are harmful species emitted by the CI engines. ...
Controlling the oxides of nitrogen (NOx) and particulate matter (PM) emissions is one of the vital goals of compression ignition (CI) engines. Implementing stringent emissions regulations has motivated researchers to adopt various strategies for controlling emissions. Gasoline compression ignition (GCI) has emerged as a prime technology to control emissions and increase engine efficiency, while using low-octane gasoline as fuel in CI engines. Preheated air, hot exhaust gas recirculation (EGR), and negative valve overlap, are required to manage the combustion instabilities in the GCI engines. However these techniques have not been used in this study in order to reduce system complexity. Low octane test fuel was prepared (G80) by blending 80 % v/v gasoline and 20 % v/v diesel. This study involved experiments to evaluate the effects of main injection timing, split injection quantities (10–30 %), and engine load (brake mean effective pressure (BMEP): 3–5 bar) on a two-cylinder GCI engine's performance, combustion, cyclic variability, emissions, and particulates. Conventional diesel combustion (CDC) mode experiments were performed using diesel. The results indicated a 5 % higher brake thermal efficiency (BTE) and comparable exhaust gas temperature (EGT) for the GCI mode compared to the baseline CDC mode. GCI combustion with low split ratio showed higher in-cylinder pressure than CDC mode. Baseline CDC mode showed < 3 % coefficient of variation of indicated mean effective pressure and peak pressure, whereas these parameters varied from 1 % to 9 % in the GCI mode. GCI mode engine exhibited ∼ 60 and 50 % lower NOx and PM emissions than baseline diesel mode engine. The double injection strategy improved GCI engine's performance and emission characteristics.
... The rate of MPRR reduction was lower for lower FIPs than its higher FIP counterpart. Won et al. (2012b) examined the effects of diesel-gasoline blends in a GCI engine. Large nozzle hole injectors exhibited higher MPRR than their small hole counterparts. ...
In the internal combustion engine types, the gasoline compression ignition engine (GCI engine) presents the potential and effective method to improve engine thermal efficiency and lower pollution emissions when compared to the spark-ignition engine (SI) and the compression ignition engine (CI engine), respectively. To improve those advantages of the GCI engine, new engine technologies are being developed to help the engine efficiently work with higher compression ratios or lower octane gasoline fuel at part load conditions. However, high smoke, soot, HC and CO formations, the part-load stability of the combustion phase, or autoignition at high load conditions are still challenging with the GCI engine. This chapter will introduce some technologies that help solve the GCI engine's challenges, these technologies are such as: injection strategy, exhaust residual gas strategy, biodiesel addition, and oxygen content. After the aforementioned technological implementations, a detailed investigation will be carried out to lay the scope on the GCI engine performance and its emission characteristics. Multiple injections may help improve combustion stability and engine efficiency when compared to a single injection strategy. The HC and CO emissions can be decreased when the engine applies a multiple injection strategy and GB05 as fuel. The increase in EGR helps to reduce autoignition for both single and numerous ignition strategies. The oxygen concentration has a sensitive effect on the delay of the ignition process. The reduced amount of oxygen concentration induces an increase in the ignition delay, which helps to reduce the auto-ignition.
... One of the many options for reducing CO2 from conventional spark-ignition engines would be to run a compression ignition (CI) engine with a gasoline-like fuel. Gasoline compression ignition (GCI) technology has been extensively studied worldwide for many years [11][12][13][14][15][16][17]. Aramco has considered GCI technologies from different approaches, both starting from a gasoline engine platform and a diesel engine platform. ...
... In summary, fuels that are more resistant to auto-ignition allow mixing time before combustion occurs and help to reduce NO X and smoke in CI engines. If the combustion phasing and delay are matched for any two fuels at a given condition, then their emissions behavior is also matched the auto-ignition resistance of the fuel is the most important fuel property when the injection is completed before the combustion starts [11][12][13]. However, a high peak of the maximum in-cylinder pressure and maximum pressure rise rate (MPRR) will be problematic at higher loads, and the combustion stability, hydrocarbon (HC), and carbon monoxide (CO) emissions can create a low operating load limitation because combustion is more likely to take place in lean mixture packets with better mixing caused by higher ignition delays. ...
... In summary, fuels that are more resistant to auto-ignition allow mixing time before combustion occurs and help to reduce NOX and smoke in CI engines. If the combustion phasing and delay are matched for any two fuels at a given condition, then their emissions behavior is also matched the auto-ignition resistance of the fuel is the most important fuel property when the injection is completed before the combustion starts [11][12][13]. However, a high peak of the maximum in-cylinder pressure and maximum pressure rise rate (MPRR) will be problematic at higher loads, and the combustion stability, hydrocarbon (HC), and carbon monoxide (CO) emissions can create a low operating load limitation because combustion is more likely to take place in lean mixture packets with better mixing caused by higher ignition delays. ...
By combining a clean fuel such as gasoline with a high efficiency thermodynamic cycle (compression ignition), it is possible to demonstrate a powertrain that is clean and efficient, thus breaking the historical trade-off between decreasing CO2 and reducing criteria pollutants. The gasoline compression ignition (GCI) engine is a promising technology that can be used to improve thermal efficiency while reducing emissions. Its low temperature combustion does however lead to several problems that need to be overcome. The present study relates to a method and system for combining the advantages of GCI engine technology into a hybrid electric vehicle (HEV) to maximize the benefits. A plausible path is to operate the GCI engine at conditions where the benefits of a GCI engine could be maximized and where an electric motor can supplement the conditions where the GCI is less beneficial. In this study, GCI engines with different cetane number (CN) fuels were selected, and a hybrid simulation tool was used to address the potential of the GCI engines into hybrid electric vehicles. Co-developments can demonstrate efficiency and emission solutions through the achievements of the study, which will address examples of the competitive powertrain and will introduce more than 30% of CO2 reduction vehicle by 2030.
... However, Zhang et al. [3], [5]] and Lee et al. [6] have shown that, for GCI operation, higher injection pressure values, in excess of 1000 bar, are required to achieve mixing-controlled operation and a subsequent reduction of particulate matter emissions (compared to diesel). Although some researchers reported that the development of low-temperature, partially premixed GCI could be used to lower the injection pressure [7]- [8], high injection pressures must still be exploited under peakload engine operation in order to constrain the total particulate emissions [9]. ...
Measurements of fuel injectors via non-destructive X-ray techniques can provide unique insights about an injector’s internal surface. Using real measured geometry rather than nominal design geometry in computational fluid dynamics simulations can improve the accuracy of the numerical models dramatically. Recent work from the authors investigated the influence of the injector design on the internal flow development and occurrence of cavitation in a production multi-hole heavy-duty diesel injector operating with a straight-run gasoline for gasoline compression ignition (GCI) applications. This was achieved by evaluating a series of design parameters which showed that the intensity and duration of cavitation structures could be mitigated by acting on certain injector parameters such as K-factor, orifice inlet ellipticity, and sac-to-orifice radius of curvature. In the present work, the findings from the previous parametric study were combined to generate two attempts at improving the injector design and numerically evaluate their ability to suppress cavitation inside the orifices at three levels of injection pressure (1000, 1500, and 2500 bar), while operating with the same high-volatility gasoline fuel. Qualitative and quantitative analyses showed that, compared to the results obtained with the original X-ray scanned geometry, the improved designs were able to prevent fuel vapor formation at the two lowest injection pressures and avoid super-cavitation at the higher pressure. It was shown that these results were due to the strong influence that the orifice shape can have on the pressure and fuel vapor volume fraction distributions within the orifices. The informed design choices proposed in this study can therefore be vital for extending the durability and reliability of heavy-duty injectors for GCI applications.
... Mixture of diesel and gasoline or low octane gasoline can extend GCI operating range with enhanced fuel stratification (Won et al. 2012a). Gasoline and diesel blend can easily match the required GCI fuel properties although safety and flash point demand of fuel can be an issue. ...
Compression ignition (CI) engines are mainly fuelled by diesel-like high cetane fuels, and they have higher overall efficiency due to higher compression ratio compared to their spark ignition (SI) engine counterparts. However, modern diesel engines are more expensive, complicated, and emit high nitrogen oxides (NOx) and particulate matter (PM). Simultaneous control of soot and NOx emissions in diesel engines is quite challenging and expensive. Thermal efficiency of SI engines, on the other hand is limited by the tendency of abnormal combustion at higher compression ratios therefore use of high octane fuel is essential for developing more efficient higher compression ratio SI engines in near future. In the foreseeable future, refineries will process heavier crude oil to produce relatively inferior petroleum products to power the IC engines. Also, fuel demand will shift more towards diesel and jet fuels, which would lead to availability of surplus amounts of low octane gasoline with oil marketing companies, with little apparent use for operating the engines. This low octane gasoline will be cheaper and would be available in excess quantities in foreseeable future as the demand for gasoline will further drop due to increase in the fuel economy of modern generation gasoline fuelled vehicles. For addressing these issues, Gasoline compression ignition (GCI) engine technology is being developed, which is a futuristic engine technology that takes advantage of higher volatility, and higher auto-ignition temperature of gasoline and higher compression ratio (CR) of a diesel engine simultaneously to take care of soot and NOx emissions without compromising diesel engine like efficiency. GCI engines can efficiently operate on low octane gasoline (RON of ~70) with better controls at part load conditions. However cold starting, high CO and HC emissions, combustion stability at part load, and high combustion noise at medium-to-full load operations are some of the challenges associated with GCI engine technology. Introductory sections of this chapter highlights future energy and transport scenario, trends of future fuel demand, availability of low octane fuels and development in advanced engine combustion technologies such as HCCI, PCCI, RCCI, and GDI. GCI engine development, its combustion characteristics and controls are discussed in detail. Particular emphasis is given to the effect of various control strategies on GCI combustion, performance and emissions, fuel
quality requirement and adaption of GCI technology in modern CI engines. In addition, this chapter reviews initial experimental studies to assess the potential benefits
of GCI technology.
... However, it has been shown that in order to achieve simultaneous mixing-controlled GCI operation and particulate emission benefits (compared to diesel), the injection pressure should be in excess of 1000 bar [3,5,6]. On the other hand, some researchers concluded that the high fuel pressure requirement could be relaxed by developing low temperature and partially premixed GCI [7,8]. Nevertheless, higher diesel-like injection pressures might still be needed in order to minimize particulate emissions under peak load engine operation [9]. ...
The occurrence of cavitation inside injectors is generally undesirable since it can cause material erosion and result in deviations from the expected operating conditions and performance. Previous numerical work employing an injector geometry measured with x-ray diagnostics and operating with a high-volatility straight-run gasoline has shown that: (1) most of the cavitation is generally observed at low needle lifts, (2) needle motion is responsible for asymmetric structures in the internal flow as well as large pressure and velocity gradients that trigger phase transition at the orifice inlets, and (3) cavitation affects the injector discharge coefficient and distribution of injected fuel. To explore the potential for material damage within the injector orifices due to cavitation cloud collapse, the cavitation-induced ero-sion risk assessment (CIERA) tool has been applied for the first time to the realistic geometry of a heavy-duty injector using the CONVERGE software. Critical locations with high erosive potential matched qualitatively well with x-ray scans of an eroded injector sample that underwent a durability test with straight-run gasoline. This motivated a CFD exploration of orifice design modifications, using a nominal reconstruction of the realistic geometry and an automated procedure for fast generation of modified surface files. In this work, the influence of the orifice K-factor on the intensity and duration of cavitation structures was investigated. Quantitative and qualitative analyses highlighted the importance of this parameter in limiting or suppressing cavitation inside the injector orifices and provided useful insights and design guidelines for injectors operating with high-volatility fuels.
... Blending gasoline and diesel (GD blends) is a convenient method to obtain WDF [5][6][7]. It has been proved [8][9][10][11][12][13][14][15][16] that due to the ignition resistance and low boiling range, increasing gasoline ratio prolongs the ignition delay and promotes the fuel evaporation, resulting in soot emission reduction. The side effect, however, is poor low-load combustion stability and efficiency. ...
GDP is a blend fuel containing gasoline, diesel, and polyoxymethylene dimethyl ethers (PODE). Previous study has shown that by combining premixed ratio and high fuel oxygen content, GDP partially premixed combustion ignition (PPCI) broke the trade-off between NOx and soot with moderate exhaust gas recirculation (EGR) while maintaining high engine efficiency. In this work, multiple premixed compression ignition (MPCI) mode was adopted to break the trade-off between fuel economy and combustion noise, which is the major challenge of the single injection GDP PPCI combustion. In this work, the MPCI adopted a double injection strategy with the second injection timing fixed at 6 crank angle degree (CAD) before top dead center (BTDC). The effects of first injection timing and split injection ratio on emissions and combustion were investigated. The results showed that GDP MPCI mode exhibited two-stage combustion. With the advance of first injection timing and the decrease of first injection quantity, the amount and rate of the first-stage heat release decreased, and those of the second-stage heat release increased. Compared with single injection PPCI, MPCI reduced the maximum HC and CO emissions by 59% and 44%, respectively. Soot emissions of MPCI mode were below 0.01 g/kW.h, while NOx emissions were controlled under 0.4 g/kW.h. The results indicated that MPCI mode could improve engine efficiency and reduce combustion noise simultaneously (low MPRR), and the optimal engine performance and emissions were achieved with 26–31 CAD BTDC first injection timing and 30–40% first injection ratio.
... In order to integrate the advantages of gasoline and diesel fuels to get lower emissions as well as high thermal efficiency, researchers have proposed some other ideas, like dual-fuel reactivity controlled compression ignition (RCCI) (two fuels mix in cylinder) [7][8][9][10][11][12][13] and premixed compression ignition (blend fuel) [14][15][16][17][18][19][20][21][22][23][24][25]. Based on these studies, a concept called wide distillation fuel (WDF) has been surfaced, which refers to fuels with distillation range from initial boiling point of gasoline to final boiling point of diesel. ...
... Kerosene is such a kind of WDF. A lot of researches have been carried out on engine performances and emissions when fuelled by gasoline/diesel blend fuel and kerosene [14][15][16][17][18][19][20][21][22][23][24][25][27][28][29][30][31], but there is few work focusing on spray characteristics of WDF. Therefore, in this paper, based on a piezoelectric injector, an extensive investigation has been conducted on the spray characteristics of WDF like gasoline/diesel blend fuel and kerosene and compared with the conventional diesel fuel. ...
... Based on air entrainment analysis, it is clear that kerosene and G50 have advantages in fuel-air mixing. Beside, lower cetane number will result in longer ignition delay to gain more time to promote fuel air mixing, which is absolutely favourable for the reduction of both PM and NOx emissions [15][16][17][18][19][20][21][22][23][24]58]. ...
In this study, the performance of piezoelectric and solenoid injectors were compared. With a piezoelectric
injector, the spray characteristics of kerosene and G50 (gasoline/diesel blend fuel), which are kinds of
WDF, were investigated and compared to diesel. The characteristics such as spray penetration, spray
velocity, spray angle and air entrainment were used to understand the spray behaviour of the test fuels.
The results indicate that the piezoelectric injector shows significant improvement over the conventional
solenoid injector in injection response and needle opening speed, which enables precise and rapid control
of injection. The trade-off effects of charge density and injection pressure on spray penetration and spray
velocity are quite clear, while spray angle is almost insensitive to injection pressure. Kerosene and G50
give smaller but similar spray penetration and velocity compared to diesel. The spray angle of kerosene
and G50 are larger compared to diesel. The spray volume and mass of entrained air for kerosene and G50
are higher compared to diesel, which indicates kerosene and G50 can form better fuel–air mixing, which
is very important for the performance of engine when fuelled by WDF
... Thus, low load cannot be easily attained by the high injection pressure. In fact, at the medium and high loads, the required injection pressure is also lower for gasoline-type fuels than diesel [20]. Considering the whole operation region, gasoline-type fuel favors the low injection pressure, which is an advantage of gasoline compression ignition. ...
... That is to say, G80 can successfully replace diesel to achieve most of the operation points. It can be expected that further reducing the octane number can offer lower load limit, however, high octane fuel have better performance at high loads than low octane fuel because of the lower pressure rise rate and lower soot emissions [20]. Thus, G80 might be more proper than other blending ratios considering the load range, the demand of boost and the emission results. ...
A study to extend the low load limit of the mixture of commercial gasoline and diesel in the compression mode is performed on a single cylinder diesel engine. The additional measures, like intake heating, rebreathing, negative valve overlap, are not employed. By adopting boosting, sweeping the injection pressure and varying the fuel octane number, the minimum fuelling rate and the minimum IMEP gained is compared. Besides, the thermal efficiency and emission results at these operation points are also discussed.
... One alternative might be to use mixtures of gasoline and diesel, ''dieseline'', to reduce the octane number of the market gasoline to better enable GCI technology e.g. [8,9]. Blends with gasoline concentrations of 50% by volume or more (most likely between 80% and 90% by volume gasoline) would be of interest for such applications. ...
