Browse Topic: Gasohol
A vehicle fleet of seven low-mileage gasoline direct injection (GDI) vehicles from the U.S. market were tested to determine if GDI injector deposits were present causing a loss in fuel economy (FE). The real-world vehicles were tested “as-is” from the field. The data shows that, even in a deposit control additive (DCA) mandated market that uses E10 gasoline, injector deposits can still result in up to 2.7 % loss in FE. In addition, the data shows that the level of real-world FE loss is comparable to that demonstrated in the GDI injector fouling test developed to simulate real-world dirty-up of GDI vehicle injectors.
Renewable synthetic fuels offer the opportunity to significantly reduce carbon dioxide (CO2) emissions worldwide if burned in the internal combustion engines of existing and future passenger car fleets. To evaluate this potential, two renewable synthetic gasoline fuels and alcohol blends that can be produced via the methanol-to-gasoline (MtG) synthesis process are evaluated in this study. The first synthetic gasoline, hereafter referred to as MtG, was developed by Chemieanlagenbau Chemnitz GmbH and Technische Universität Bergakademie Freiberg, produced within the closed carbon cycle mobility (C3-Mobility) project, and was blended with 10%(V/V) ethanol (MtG-E10), 20%(V/V) ethanol (MtG-E20), 15%(V/V) methanol (MtG-M15), and 15%(V/V) 2-butanol (MtG-2Bu15). The second synthetic fuel, named POSYN (POrsche SYNthetic fuel), was developed by Porsche. The suitability of the synthetic fuels was experimentally investigated in a spark-ignition (SI) single-cylinder research engine with a compression ratio (CR) of 10.8 and compared with conventional gasoline fuel with Research Octane Number 95 and 10%(V/V) ethanol (RON95 E10) gasoline fuel. Load variations at a constant engine speed of 2500 rpm showed no significant differences between Methanol-to-Gasoline with 10%(V/V) ethanol (MtG-E10) and RON95 E10 in terms of both combustion performance and emissions. Additionally, a load variation with MtG-E10 and RON95 E10 at an engine speed of 3000 rpm was performed on a commercially available BMW multi-cylinder engine (MCE), which confirmed that both these fuels show an almost identical combustion and emission behavior. However, the knock resistance improved with higher alcohol fractions. Because of the favorable anti-knock properties of methanol, Methanol-to-Gasoline with 15%(V/V) methanol (MtG-M15) showed the highest maximum net indicated efficiency of 39.33%. This is 2% more than with Methanol-to-Gasoline with 20%(V/V) ethanol (MtG-E20), despite the lower alcohol volume fraction. In contrast, Methanol-to-Gasoline with 15%(V/V) 2-butanol (MtG-2Bu15) showed no improvement. POSYN enabled a significant efficiency advantage over RON95 E10 because of its high knock resistance, however, achieved the same maximum engine load because of the reduced octane sensitivity. The variation of the relative air/fuel ratio at an engine speed of 2500 rpm and an engine load of 16 bar net indicated mean effective pressure confirmed these findings. The highest net indicated efficiency of 42.4% was achieved with POSYN at a relative air/fuel ratio of 1.6. The lean limit could not be increased with the synthetic fuels and alcohol blends albeit with an improved combustion stability.
In order to maximize the efficiency of light-duty gasoline engines, the Co-Optimization of Fuels and Engines (Co-Optima) initiative from the U.S. Department of Energy is investigating multi-mode combustion strategies. Multi-mode combustion can be describe as using conventional spark-ignited combustion at high loads, and at the part-load operating conditions, various advanced compression ignition (ACI) strategies are being investigated to increase efficiency. Of particular interest to the Co-Optima initiative is the extent to which optimal fuel properties and compositions can enable higher efficiency ACI combustion over larger portions of the operating map. Extending the speed-load range of these ACI modes can enable greater part-load efficiency improvements for multi-mode combustion strategies. In this manuscript, we investigate fuel effects for six different fuels, including four with a research octane number (RON) of 98 and differing fuel chemistries, iso-octane, and a market representative E10 fuel, on the load limits for two different ACI strategies: spark-assisted compression ignition (SACI) and partial fuel stratification-gasoline compression ignition (PFS-GCI) operation. Experimental results show that limits to intake boosting limit high load operation for most fuels, but high smoke emissions for high particulate matter index (PMI) fuels under SACI conditions could also be a limitation. Contrastingly, low load is limited by combustion efficiency, but these effects have more pronounced variation with fuel chemistry for PFS-GCI than with SACI. Additional, distinct effects affecting autoignition timing and peak heat release at higher speeds were identified for fuels having different low temperature heat release (LTHR) propensities for both ACI modes.
Ethanol is regarded as a potential alternative fuel for combustion engine as it provides lower exhaust emissions, higher efficiency and higher octane rating. However, the solubility of ethanol in oil can effect lubricant quality. The impact of ethanol-blend gasoline on lubricants is a matter of concern that must be addressed. With this in mind, the current study investigates the effect of blending ethanol with gasoline on the oil layer adsorption/desorption mechanism. The blends used for the study are E0, E5, E10, and E15. The study is carried out with the help of a mathematical model that predicts the fuel adsorbed/desorbed in the oil layer of an engine. The mathematical model predictions are compared to experimental results obtained on a single-cylinder gasoline engine. Fuel adsorbed in the oil layer ranges from 0.46% for E0 fuel to 0.35% for E15 fuel. Similarly, the desorbed fuel ranges from 0.45% to 0.29% as the ethanol fraction increases from 0% to 15%. Despite the fact that the amount of fuel adsorbed/desorbed in the oil layer decreases as the ethanol fraction increases, the amount of fuel stored in the oil layer (i.e., the difference between adsorbed and desorbed fuel) increases from 0.01 percent to 0.06 percent which can significantly degrade the lubricant quality.
Chassis dynamometer tests were conducted on three Class III on-highway motorcycles produced for the North American market and equipped with advanced emission control technologies in order to inform emissions inventories and compare the impacts of existing Tier 2 (E0) fuel with more market representative Tier 3 and LEV III certification fuels with 10% ethanol. For this study, the motorcycles were tested over the US Federal Test Procedure (FTP) and the World Motorcycle Test Cycle (WMTC) certification test cycles as well as a sample of real-world motorcycle driving informally referred to as the Real World Driving Cycle (RWDC). The primary interest was to understand the emissions changes of the selected motorcycles with the use of certification fuels containing 10% ethanol compared to 0% ethanol over the three test cycles. Generally, for most of the test motorcycle/drive cycle combinations, the use of E10 certification fuels compared to Tier 2 (E0) resulted in reductions in CO, HC, NMHC; with some FTP and RWDC tests showing increased NOx emissions. Reductions in CO2 with the use of E10 fuels were noted with N2O and CH4 emissions having little impact onCO2 equivalent emissions. PM mass emission rates were below 1 mg/km with no discernable trends concerning fuel changes. Tier 3 and LEV III E10 fuels also resulted in emissions changes to a suite of air toxics, including 17 carbonyl compounds, 1,3-butadiene, BTEX, styrene, and five C9 aromatics. Acetaldehyde emissions increased significantly with the E10 fuels for all motorcycle/drive cycle combinations, while toluene and benzene emissions decreased. The estimated ozone formation potential of the 30 compounds was reduced with the E10 fuels compared to Tier 2. Overall, this study, which examined the emission profiles of multiple motorcycles, test cycles, and in-use driving samples, provides insights on the emission inventory impacts from the introduction of ethanol-containing fuels, over a range of motorcycles, reflective of the North American in-use fleet.
Ethanol has shown tremendous potential in the journey of substitution of fossil fuels in the recent past. Primarily, the ethanol blends up to 10% in gasoline used in many countries as the existing vehicles are compatible with lower ethanol content. However, it is essential to address the compatibility of the vehicle’s fuel system when using higher ethanol-containing blends. The current study focused on the compatibility of different ethanol-gasoline blends with two widely used elastomer materials in the vehicle’s fuel system, namely, nitrile butadiene rubber/polyvinyl chloride blend (NBR/PVC) and epichlorohydrin (ECO). These materials are used for manufacturing parts like seals, gaskets, hoses/tubes, and cover of the fuel systems. The test fuels used in this study include commercial gasoline (E0), gasoline containing 10% ethanol (E10), 12% ethanol (E12), 15% ethanol (E15), and 20% ethanol (E20). The compositional analysis of NBR/PVC blend and ECO samples was undertaken using Carbon, Hydrogen, Nitrogen, Sulfur (CHNS) analyzer, Fourier-transform infrared (FTIR) spectroscopy, and Thermogravimetric Analysis (TGA). The test material specimens were immersed in test fuels at an elevated temperature of 55 ± 2°C for 1008 hr, or six weeks. Critical properties of material specimens under fresh, post immersion (wet), and dry conditions were analyzed. These properties include visual inspection, volume change, weight change, hardness change, tensile strength, and percentage (%) elongation change. Variations in properties of test specimens were used to illustrate the compatibility with test fuels. The results indicate that the volume change and weight change correspond well with hardness, tensile strength, and % elongation trends. The behavior of E10 and E12 fuels with test materials were found to be similar within a 5.0% tolerance. As we move to E15 and E20, the performance of elastomers changed moderately in certain properties, tensile strength, and % elongation change in particular.
In view of the new emission regulations seeking to lower the particle cut-off size down to the current 23 nm, an extensive comprehension on the nature of sub-23 nm particles is crucial. In this regard, a new challenge lies ahead considering an even more massive use of biofuels. The objective of this research study was to characterize the sub-23 nm particles and to evaluate their volatile organic fraction (VOF) from a high performance, 1.8 L gasoline direct injection (GDI) engine under the Worldwide harmonized Light vehicles Test Cycle (WLTC). Particle emissions were measured through an Engine Exhaust Particle Sizer (EEPS) capable of particle sizing and counting in the range 5.6 - 560 nm. The sampling and conditioning were performed by both a single diluter and the Dekati Engine Exhaust Diluter (DEED) a Particle Measurement Programme (PMP) compliant sample conditioning system. The temperature of the dilution air at the first dilution stage and of the evaporation chamber in the DEED were varied to promote nucleation and condensation phenomena thus allowing to distinguish the VOF. The effect of ethanol at 10 %v/v (E10) and 85 %v/v (E85) blend on particle emissions was analyzed. The weight of sub-23 particles on the total emissions was assessed at each phase of the cycle. Main results highlighted that sub-23 nm particles give an important contribution to the total particle emissions. A strong reduction of particle concentration as the ethanol content in the fuel increases was observed. Moreover, the test performed at low dilution temperature showed a large number of su-23 nm particles thus revealing a large fraction of volatile components in specific phases of the cycle.
Low-temperature gasoline combustion engines can provide high efficiencies with very low NOx and particulate emissions, but rapid control of the combustion timing (50% burn point, CA50) remains a challenge. Partial Fuel Stratification (PFS) was recently demonstrated [2019-01-1156] to control CA50 over a wide range at some selected operating conditions using a regular-grade E10 gasoline. PFS was produced by a double direct injection (D-DI) strategy using a gasoline-type direct injector. For this D-DI-PFS strategy, the majority of the fuel is injected early in the intake stroke, establishing the minimum equivalence ratio in the charge, while the remainder of the fuel is supplied by a second injection at a variable time (SOI2) during the compression stroke to vary the amount of stratification. Adjusting the stratification changes the combustion timing, and this can be done on a cycle-to-cycle basis by adjusting SOI2. The current work expands the understanding of D-DI-PFS by investigating the effects of global equivalence ratio, variations in the fuel-fraction split between the two injections, and intake pressure on the ability of D-DI-PFS to control CA50, for both a regular-grade gasoline and this same gasoline additized with 2-ethylhexyl nitrate (EHN) to enhance its autoignition reactivity. Moreover, the understanding gained from these fixed-load experiments was applied to determine the ability of D-DI-PFS to control CA50 through a load sweep from 0.42 ≥ φ ≥ 0.30 at intake pressures equal to 1.0 bar and 1.3 bar for both the non-additized and EHN-additized gasolines. For each load, SOI2 was adjusted to keep CA50 between the knock and misfire limits, while also considering emissions constraints. For both fuels, D-DI-PFS was shown to be effective for maintaining appropriate CA50 phasing over the sweep. Furthermore, NOx emissions were kept close to the US-2010 HD limit and combustion stability (COV-IMEPg) was kept to a reasonable value.
Mixture formation in GDI engine is considered crucial in determining combustion and emissions characteristics, which mainly depend on fuel spray quality. However, spray characteristics change with variations in control parameters such as fuel injection parameters, fuel injection strategy, engine operating conditions, and fuel properties. Growing research interest in the use of methanol as an additive with gasoline has motivated the need for deeper investigations of spray characteristics of these fuels. Although, it can be noted that sufficient literature is available in the area of spray characterization under several independent influencing factors, however, comparative analysis of gasohol spray behavior under different ambient conditions is hardly studied. This study is aimed at investigating the spray morphology, and evaporation and mixing characteristics of M15 (15% v/v methanol in iso-octane) and M85 (85% v/v methanol in iso-octane) in comparison to iso-octane at early injection and late injection conditions. CFD simulation studies were performed using multi-hole GDI injector in a constant volume spray chamber (CVSC) using Converge software. Numerical model used for the analysis was validated using experimental spray penetration measurements, available at the ECN. The results highlighted that effect of methanol properties on spray penetration and SMD of fuel droplets diminished under high temperature-high pressure conditions. Although, substantial difference in droplets evaporation was found among the test fuels due to inferior volatility of methanol, which definitely demands optimization of fuel injection parameters for adapting methanol blends in the engine. However, despite lower droplet evaporation, equivalence ratio distribution for methanol blends was more shifted towards stoichiometric conditions due to inherent fuel oxygen content.
Particulate matter, mainly its finer fraction, is among the main atmospheric pollutants present in an urban environment. The relationship between the increase in the concentration of this pollutant and the harm to human health is well established. The main sources of particulate matter in urban areas are mobile sources, which includes the exhaust emission from light duty vehicles. In Brazil since its advent in 2003, there has been great penetration in the market for bi-fuel or "flex" vehicles, which use ethanol, gasoline or their mixtures as fuel. More recently, with the introduction of public policies that led to the adoption of improvements in the energy efficiency of vehicles, the use of direct fuel injection technology (GDI), as a trend in downsizing for improved fuel economy, gained prominence. This technology optimizes the burning process in the combustion chamber of the engines, making their use more efficient. On the other hand, it has the side effect of a higher emission of particulate matter compared to engines that use indirect injection. This higher emission is aggravated by the fact that the particulate matter is extremely fine, precisely the most harmful fraction because it contains a large amount of inhalable particles. This work measured the emission of particulate matter in light passenger vehicles, characterizing it in terms of emitted mass in "flex" vehicles with port fuel (indirect) injection (PFI), using ethanol and gasoline, and in a gasoline vehicle with direct fuel injection. For the four flex fuel PFI vehicles, the average emission of particulate matter was 1.1 ± 0.3 mg.km-1 for the tests running ethanol, and 1.0 ± 0.3 mg.km-1 for gasohol. For the vehicle equipped with GDI the average emission, with gasohol fuel was 2.8 ± 0.2 mg.km-1.
The compatibilities of fuel system elastomers and plastics were evaluated for test fuels containing 16 vol.% isobutanol (iBu16) and 10 vol.% ethanol (E10). Elastomers included two fluorocarbons, four acrylonitrile butadiene rubbers (NBRs), and one type of fluorosilicone, neoprene, and epichlorohydrin/ethylene oxide. Plastic materials included four nylon grades, three polyamides, polytetrafluoroethylene (PTFE), polyvinylidene fluoride (PVDF), ethylene tetrafluoroethylene (ETFE), polyphenylene sulfide (PPS), high-density polyethylene (HDPE), polybutylene terephthalate (PBT), polyoxymethylene (POM), flexible polyvinylchloride (PVC), polyetherimide (PEI), polyetheretherketone (PEEK), and a phenol formaldehyde reinforced with glass fiber (GFPF). For each polymer material, the volume, mass, and hardness were measured before and after drying. Dynamic mechanical analysis (DMA) measurements were also performed on the dried specimens. For the elastomer materials the measured properties were similar for both fuels. The fluorocarbons and fluorosilicone swelled the least (~20%), while more moderate (20-45%) expansion occurred for the two NBR hose grades and (ECO). HNBR, neoprene, and silicone exhibited high swelling and softening, which likely precludes their use in many fuel systems. For the plastic materials, the observed swell was low; Nylon 11 swelled around 15%, but otherwise, their measured swell was <10%. Many of the plastics also showed sensitivity to alcohol type, as the E10 test fuel often imparted appreciably higher swell than iBu16. In general, the plastic materials showed good compatibility with the iBu16 and E10 test fuels. The sole exception was the PVC material, which was structurally degraded from exposure to either fuel type. Compositional analysis showed high fuel retention in Nylon 12 and PVC. PVC also experienced a significant reduction in plasticizer compounds following exposure, which resulted in embrittlement and an increase in the glass-to-rubber transition temperature.
Gasoline compression ignition (GCI) technology shows the potential to obtain high thermal efficiencies while maintaining low soot and NOx emissions in light-duty engine applications. Recent experimental studies and numerical simulations have indicated that high reactivity gasoline-like fuels can further enable the benefits of GCI combustion. However, there is limited empirical data in the literature studying the gasoline compression ignition process at relevant in-cylinder conditions, which are required for further optimizing combustion system designs. This study investigates the temporal and spatial evolution of the compression ignition process of various high reactivity gasoline fuels with research octane numbers (RON) of 71, 74 and 82, as well as a conventional RON 97 E10 gasoline fuel. A ten-hole prototype gasoline injector specifically designed for GCI applications capable of injection pressures up to 450 bar was used. Vapor and liquid penetration from high speed optical visualizations, as well as combustion measurement were studied in an optically accessible constant volume spray and combustion chamber. Near simultaneous shadowgraph and Mie scattering images were captured to investigate the spray characteristics. OH* chemiluminescence and natural luminosity images were recorded simultaneously to characterize the ignition process through two high-speed cameras. The experiments were conducted under a wide range of ambient charge gas conditions, including temperatures from 900 to 1200 Kelvin, charge gas pressures from 50 to 100 bar, oxygen levels from 10-21% to represent 0-50% exhaust gas recirculation (EGR) levels. The fuel was injected at 300 and 450 bar injection pressure. Results show that vapor penetration of the E10 and high reactivity gasoline fuels are similar, and the liquid penetration is related to the fuel density. With the OH* chemiluminescence images analysis, the ignition delay decreases, and the flame lift-off length moves upstream towards the injector tip with increasing ambient temperature, increasing charge gas pressure, increasing cetane number and decreasing EGR level. A gasoline ignition delay correlation and a lift-off length correlation considering the charge gas conditions and the fuel properties have been achieved.
The effect of low level ethanol fuel on the power and emissions characteristics was studied in a small, mass produced, carbureted, spark-ignited, Briggs and Stratton Vanguard 19L2 engine. Ethanol has been shown to be an attractive renewable fuel by the automotive industry; having anti-knock properties, potential power benefits, and emissions reduction benefits. With increasing availability and the possible mandates of higher ethanol content in pump gasoline, there is interest in exploring the effect of using higher content ethanol fuels in the small utility engine market. The fuels in this study were prepared by gravimetrically mixing 98.7% ethanol with a balance of 87 octane no-ethanol gasoline in approximately 5% increments from pure gasoline to 25% ethanol. Alcor Petrolab performed fuel analysis on the blended fuels and determined the actual volumetric ethanol content was within 2%. The purpose of this study is to evaluate the performance and emissions of a small utility engine across several load points. Compared to previous works, this study concentrated on engine operation at wide open throttle as any decrease in engine power output due to a fuel's ethanol content would negatively impact an engine's sales potential; small engines developed for this market sector are engineered to meet a certain horsepower rating. For this study, the engine governor was set at 3800 rpm. After the engine governor was adjusted to its maximum position (i.e. 3800 rpm), the engine was loaded by a hydraulic dynamometer. As the load was increased, the engine speed slowly decreased as the dynamometer's torque was increased. Full load engine operation down to an engine speed of approximately 2800 rpm, just higher than the engine's torque peak, was investigated. In addition to engine out emissions and shaft power, exhaust temperatures and cylinder pressure were recorded. Overall, the experimental results showed increasing ethanol content results in a small gain in power output even though the energy content of the fuel was decreasing. It was found that nitrogen oxides plus hydrocarbons emissions slightly decreased or stayed equivalent while the carbon monoxide emissions were reduced by 10% for the E10 blend and by 20% for the E15 blend. Finally, cylinder pressure and heat release analysis showed that the addition of ethanol increased peak cylinder pressure and advanced the main heat release closer towards top dead center.
Flash boiling, as a potential way to achieve good atomization at low cost, is of great interest to researchers. A customized wide-angle multi-hole gasoline injector was utilized in this work to see how commercial E10 gasoline spray behaves at high injection pressure of gasoline compression ignition (GCI) application from 5 MPa to 45 MPa, and ambient gas pressure from 3 kPa to 300 kPa . A diffused back illumination technique was implemented to visualize the spray at flash boiling and non-flashing conditions. Three different types of spray pattern were observed and correlated to the characteristics like penetration length and spray width. A new parameter, namely optical thickness, was applied in the field of characterizing flash boiling effect for the first time, and compared with widely used penetration length and spray width. Optical thickness was found to be a good indicator for collapse, transition, and non-flashing spray.
The compatibility of four potential bio-derived blendstock molecules with infrastructure elastomers was determined by measuring the volume change following exposure. The blendstock molecules included 1-propanol, diisobutylene, cyclopentanone, and a furan mixture. The elastomers included two fluorocarbons, six nitrile rubbers (NBRs), and one each of fluorosilicone, neoprene, polyurethane, and silicone. The elastomers were exposed to the fuel molecules as blends ranging from 0 to 30 vol.% in both a blendstock for oxygenate blending (BOB) formulation and an E10 fuel. Silicone exhibited excessive swelling in each test fuel, while the other elastomers showed good compatibility (low swell) with diisobutylene, 1-propanol, and the furan mixture when BOB was used as the base fuel. The E10 base fuel produced high (>30%) swell in neoprene, polyurethane, and some nitrile rubbers. In most cases diisobutylene produced the least amount of volume expansion. In contrast, the addition of cyclopentanone produced unacceptably high swelling in each elastomer and is not considered suitable for use with these fuels. Analysis of the results showed that the swelling behavior is predominantly due to the polarity of the elastomer and test fuels.
In current production natural gas/gasoline bi-fuel vehicles, fuels are supplied via port fuel injection (PFI). Injecting a gaseous fuel in the intake port significantly reduces the volumetric efficiency and consequently torque as compared to gasoline. In addition to eliminating the volumetric efficiency challenge, direct injection (DI) of natural gas (NG) can enhance the in-cylinder flow, mixing, and combustion process resulting in improved efficiency and performance. A computational fluid dynamics (CFD) approach to model high-pressure gaseous injection was developed and validated against X-ray data from Argonne’s Advanced Photon Source. NG side and central DI of various designs and injection strategies were assessed experimentally along with CFD correlation. Significant effects on combustion metrics were quantified and explained via improved understanding of the in-cylinder flow effects due to NG injection. On-demand in-cylinder blending using E10 PFI and NG DI provides an additional lever to adjust in-cylinder turbulence as well as knock resistance across the engine speed and load range. NG DI improves part-load dilution tolerance due to higher in-cylinder turbulence and the high knock resistance of NG compared to E10 improves wide open throttle (WOT) performance while enabling increased compression ratios (CR). Vehicle level simulations suggest that implementing this strategy on a ½ ton pick-up truck with a naturally aspirated engine at 12.5:1 CR improves energy consumption on the aggressive US06 drive cycle by 15.5% compared to E10 operation, and gives a petroleum reduction of 78% over the blended range. There are challenges regarding market acceptance and widespread adoption of dual-fuel NG-gasoline vehicle applications beyond the performance degradation when the vehicle runs out of natural gas. Those challenges include practical concerns such as loss of cargo volume and payload due to the NG storage tank, extended NG refueling times, fueling convenience due to gasoline and NG fuel tanks, and limited NG fueling infrastructure.
When fuel at elevated temperatures is injected into an ambient environment at a pressure lower than the saturation pressure of the fuel, the fuel vaporizes in the nozzle and/or immediately upon exiting the nozzle; that is, it undergoes flash boiling. It is characterized by a two-phase flow regime co-located with primary breakup, which significantly affects the spray characteristics. Under flash boiling conditions, the near nozzle spray angle increases, which can lead to shorter penetration because of increased entrainment. In a multi-hole injector this can cause other impacts downstream resulting from the increased plume to plume interactions. To study the effect of injector temperature and injection pressure with real fuels, an experimental investigation of the spray characteristics of a summer grade gasoline fuel with 10% ethanol (E10) was conducted in an optically accessible constant volume spray vessel. A gasoline direct-injection injector with six holes typical of a side-injection engine was studied. Optical diagnostics included high-speed photography with alternate frame imaging from Mie-Scattering and Shadowgraph techniques. Ambient conditions representing Early Injection (45°C, 1 bar) and Late Injection (180°C, 4bar) conditions representative of gasoline direct injection events were studied at injector temperatures from 75 to 250°C and at injection pressures of 100, 150, 200 and 250 bar. Results showed that for early injection condition, increased fuel temperature leads to two primary effects due to flash boiling: (i) an appreciable increase in spray angle near the nozzle exit followed by (ii) a decrease downstream of the nozzle due to the interaction of the plumes and collapsing sprays. For the early injection condition, spray penetration was observed to be minimum at 100°C followed by an increase in penetration at higher temperatures due to the collapsing sprays. For the late injection condition, the spray angle at the exit and downstream of the nozzle decreased with temperature. Besides, increased injection pressures lead to increased spray penetration due to higher injection momentum of the sprays outperforming the plume to plume interactions.
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