Dr Yuhan Huang received his Bachelor degree from the Huazhong University of Science and Technology (HUST) in 2011, and PhD degrees from the HUST in 2016 and University of Technology Sydney (UTS) in 2017 (UTS-HUST dual-degree program). All are in the area of spray, combustion and emissions of internal combustion engines.
Dr Huang is currently a Postdoctoral Research Fellow in vehicle emissions and air quality at the School of Civil and Environmental Engineering of UTS. His research is presently focused on remote sensing of on-road vehicle emissions and eco-driving for reducing fuel consumption and emissions.
Dr Huang serves as a reviewer for
· Applied Thermal Engineering
· Energy Conversion and Management
· Energy and Buildings
· SAE International Journal of Engines
Can supervise: YES
- Air quality and vehicle emissions
- Internal combustion engines
- Computational fluids dynamics
- Renewable energy
Al-Muhsen, NFO, Huang, Y & Hong, G 2019, 'Effects of direct injection timing associated with spark timing on a small spark ignition engine equipped with ethanol dual-injection', FUEL, vol. 239, pp. 852-861.View/Download from: Publisher's site
Huang, Y, Surawski, NC, Organ, B, Zhou, JL, Tang, OHH & Chan, EFC 2019, 'Fuel consumption and emissions performance under real driving: Comparison between hybrid and conventional vehicles.', Science of the Total Environment, vol. 659, pp. 275-282.View/Download from: UTS OPUS or Publisher's site
Hybrid electric vehicles (HEVs) are perceived to be more energy efficient and less polluting than conventional internal combustion engine (ICE) vehicles. However, increasing evidence has shown that real-driving emissions (RDE) could be much higher than laboratory type approval limits and the advantages of HEVs over their conventional ICE counterparts under real-driving conditions have not been studied extensively. Therefore, this study was conducted to evaluate the real-driving fuel consumption and pollutant emissions performance of HEVs against their conventional ICE counterparts. Two pairs of hybrid and conventional gasoline vehicles of the same model were tested simultaneously in a novel convoy mode using two portable emission measurement systems (PEMSs), thus eliminating the effect of vehicle configurations, driving behaviour, road conditions and ambient environment on the performance comparison. The results showed that although real-driving fuel consumption for both hybrid and conventional vehicles were 44%-100% and 30%-82% higher than their laboratory results respectively, HEVs saved 23%-49% fuel relative to their conventional ICE counterparts. Pollutant emissions of all the tested vehicles were lower than the regulation limits. However, HEVs showed no reduction in HC emissions and consistently higher CO emissions compared to the conventional ICE vehicles. This could be caused by the frequent stops and restarts of the HEV engines, as well as the lowered exhaust gas temperature and reduced effectiveness of the oxidation catalyst. The findings therefore show that while achieving the fuel reduction target, hybridisation did not bring the expected benefits to urban air quality.
Huang, Y, Ng, ECY, Yam, YS, Lee, CKC, Surawski, NC, Mok, WC, Organ, B, Zhou, JL & Chan, EFC 2019, 'Impact of potential engine malfunctions on fuel consumption and gaseous emissions of a Euro VI diesel truck', Energy Conversion and Management, pp. 521-529.View/Download from: UTS OPUS or Publisher's site
© 2019 Elsevier Ltd Although new vehicles are designed to comply with specific emission regulations, their in-service performance would not necessarily achieve them due to wear-and-tear and improper maintenance, as well as tampering or failure of engine control and exhaust after-treatment systems. In addition, there is a lack of knowledge on how significantly these potential malfunctions affect vehicle performance. This study was therefore conducted to simulate the effect of various engine malfunctions on the fuel consumption and gaseous emissions of a 16-tonne Euro VI diesel truck using transient chassis dynamometer testing. The simulated malfunctions included those that would commonly occur in the intake, fuel injection, exhaust after-treatment and other systems. The results showed that all malfunctions increased fuel consumption except for the malfunction of EGR fully closed which reduced fuel consumption by 31%. The biggest increases in fuel consumption were caused by malfunctions in the intake system (16%–43%), followed by the exhaust after-treatment (6%–30%), fuel injection (4%–24%) and other systems (6%–11%). Regarding pollutant emissions, the effect of engine malfunctions on HC and CO emissions was insignificant, which remained unchanged or even reduced for most cases. An exception was EGR fully open which increased HC and CO emissions by 343% and 1124%, respectively. Contrary to HC and CO emissions, NO emissions were significantly increased by malfunctions. The largest increases in NO emissions were caused by malfunctions in the after-treatment system, ranging from 38% (SCR) to 1606% (DPF pressure sensor). Malfunctions in the fuel injection system (24%–1259%) and intercooler (438%–604%) could also increase NO emissions markedly. This study demonstrated clearly the importance of having properly functioning engine control and exhaust after-treatment systems to achieve the required performance of fuel consumption and pollutant emissions.
Zhang, Y, Huang, R, Huang, Y, Huang, S, Ma, Y, Xu, S & Zhou, P 2018, 'Effect of ambient temperature on the puffing characteristics of single butanol-hexadecane droplet', Energy, vol. 145, pp. 430-441.View/Download from: UTS OPUS or Publisher's site
Zhang, Y, Huang, Y, Huang, R, Huang, S, Ma, Y, Xu, S & Wang, Z 2018, 'A new puffing model for a droplet of butanol-hexadecane blends', Applied Thermal Engineering, vol. 133, pp. 633-644.View/Download from: UTS OPUS or Publisher's site
Wang, Z, Wu, S, Huang, Y, Huang, S, Shi, S, Cheng, X & Huang, R 2018, 'Experimental investigation on spray, evaporation and combustion characteristics of ethanol-diesel, water-emulsified diesel and neat diesel fuels', Fuel, vol. 231, pp. 438-448.View/Download from: UTS OPUS or Publisher's site
© 2018 This paper explored the spray and combustion characteristics of ethanol-diesel (E10), water-emulsified diesel (W10) and neat diesel (D100), especially micro-explosion of E10 and W10. The experiments were conducted in a constant volume combustion chamber under cold (383 K, 0% O2), evaporating (900 K, 0% O2) and combustion (900 K, 21% O2) conditions. Results showed that the spray expansion capacities of E10 and W10 under cold condition were much weaker than that of D100 due to the larger viscosity of emulsified diesels. Under evaporating condition, the spray volume of E10, W10 and D100 increased by 59%, 34% and 21% respectively comparing with cold spray volume. The higher increasing rates of E10 and W10 were mainly due to the micro-explosion effects of ethanol and water contents. Under combustion condition, the integrated natural flame luminosity (INFL) demonstrated that the ethanol content could accelerate the oxidation of soot, while the water content could prohibit soot generation. Therefore, both ethanol- and water-emulsified diesels could inhibit the soot emission, causing lower final residual soot emission of E10 and W10 than that of D100 by 21% and 39% respectively. Moreover, the flame lift-off length (LOL) and flame spread velocity showed that the effects of micro-explosion in E10 and W10 are different. The micro-explosion in ethanol occurred earlier, which enhanced the reaction rate in upstream flame and reduced the LOL. However, the micro-explosion in W10 occurred later, which enhanced the combustion rate in downstream flame.
Zhang, Y, Huang, R, Huang, Y, Huang, S, Zhou, P, Chen, X & Qin, T 2018, 'Experimental study on combustion characteristics of an n-butanol-biodiesel droplet', Energy, vol. 160, pp. 490-499.View/Download from: UTS OPUS or Publisher's site
© 2018 Elsevier Ltd This work was aimed to study droplet combustion which was a foundation of spray combustion. Combustion characteristics of BUT00 (pure biodiesel) and BUT50 (50% n-butanol and 50% biodiesel by mass) were investigated using droplet suspension technology under 1 bar and 900 K. One flame was observed for BUT00 while two flames were observed for BUT50. The flame of BUT00 underwent successively faint luminosity, bright luminosity, soot aggregate and soot spread. The first flame of BUT50 was faint and the second one was similar to that of BUT00 because they were caused by n-butanol and biodiesel combustion respectively. Before the auto-ignition of BUT00, (D/D 0 ) 2 was approximately unchanged at 1.0 and similarity degree (SD) was higher than 97%. Temperature growth rate (TGR) decreased first quickly and then slowly. After the auto-ignition of BUT00, (D/D 0 ) 2 sharply decreased and SD was in the range of 90–97%. The flame heating led to the increase of TGR. For BUT50, obvious fluctuations were found in (D/D 0 ) 2 , SD and TGD. The SD of BUT50 was generally lower than 97%. The (D/D 0 ) 2 of BUT50 included transient heating, fluctuation evaporation and equilibrium evaporation phases. Some characteristic parameters were deterministic although (D/D 0 ) 2 in fluctuation evaporation phase was a non-deterministic process.
Huang, Y, Organ, B, Zhou, JL, Surawski, NC, Hong, G, Chan, EFC & Yam, YS 2018, 'Emission measurement of diesel vehicles in Hong Kong through on-road remote sensing: Performance review and identification of high-emitters', ENVIRONMENTAL POLLUTION, vol. 237, pp. 133-142.View/Download from: UTS OPUS or Publisher's site
Huang, Y, Organ, B, Zhou, JL, Surawski, NC, Hong, G, Chan, EFC & Yam, YS 2018, 'Remote sensing of on-road vehicle emissions: Mechanism, applications and a case study from Hong Kong', ATMOSPHERIC ENVIRONMENT, vol. 182, pp. 58-74.View/Download from: UTS OPUS or Publisher's site
Huang, Y, Ng, ECY, Zhou, JL, Surawski, NC, Chan, EFC & Hong, G 2018, 'Eco-driving technology for sustainable road transport: A review', Renewable and Sustainable Energy Reviews, vol. 93, pp. 596-609.View/Download from: UTS OPUS or Publisher's site
© 2018 Elsevier Ltd Road transport consumes significant quantities of fossil fuel and accounts for a significant proportion of CO2 and pollutant emissions worldwide. The driver is a major and often overlooked factor that determines vehicle performance. Eco-driving is a relatively low-cost and immediate measure to reduce fuel consumption and emissions significantly. This paper reviews the major factors, research methods and implementation of eco-driving technology. The major factors of eco-driving are acceleration/deceleration, driving speed, route choice and idling. Eco-driving training programs and in-vehicle feedback devices are commonly used to implement eco-driving skills. After training or using in-vehicle devices, immediate and significant reductions in fuel consumption and CO2 emissions have been observed with slightly increased travel time. However, the impacts of both methods attenuate over time due to the ingrained driving habits developed over the years. These findings imply the necessity of developing quantitative eco-driving patterns that could be integrated into vehicle hardware so as to generate more constant and uniform improvements, as well as developing more effective and lasting training programs and in-vehicle devices. Current eco-driving studies mainly focus on the fuel savings and CO2 reduction of individual vehicles, but ignore the pollutant emissions and the impacts at network levels. Finally, the challenges and future research directions of eco-driving technology are elaborated.
Huang, Y, Yam, YS, Lee, CKC, Organ, B, Zhou, JL, Surawski, NC, Chan, EFC & Hong, G 2018, 'Tackling nitric oxide emissions from dominant diesel vehicle models using on-road remote sensing technology.', Environmental pollution (Barking, Essex : 1987), vol. 243, no. Pt B, pp. 1177-1185.View/Download from: UTS OPUS or Publisher's site
Remote sensing provides a rapid detection of vehicle emissions under real driving condition. Remote sensing studies showed that diesel nitrogen oxides emissions changed little or were even increasing in recent years despite the tightened emission standards. To more accurately and fairly evaluate the emission trends, it is hypothesized that analysis should be detailed for individual vehicle models as each model adopted different emissions control technologies and retrofitted the engine/vehicle at different time. Therefore, this study was aimed to investigate the recent nitric oxide (NO) emission trends of the dominant diesel vehicle models using a large remote sensing dataset collected in Hong Kong. The results showed that the diesel vehicle fleet was dominated by only seven models, accounting for 78% of the total remote sensing records. Although each model had different emission levels and trends, generally all the dominant models showed a steady decrease or stable level in the fuel based NO emission factors (g/kg fuel) over the period studied except for BaM1 and BdM2. A significant increase was observed for the BaM1 2.49L and early 2.98L models during 2005-2011, which we attribute to the change in the diesel fuel injection technology. However, the overall mean NO emission factor of all the vehicles was stable during 1991-2006 and then decreased steadily during 2006-2016, in which the emission trends of individual models were averaged out and thus masked. Nevertheless, the latest small, medium and heavy diesel vehicles achieved similar NO emission factors due to the converging of operation windows of the engine and emission control devices. The findings suggested that the increasingly stringent European emission standards were not very effective in reducing the NO emissions of some diesel vehicle models in the real world.
Zhang, Y, Huang, R, Xu, S, Huang, Y, Huang, S, Ma, Y & Wang, Z 2017, 'The effect of different n-butanol-fatty acid methyl esters (FAME) blends on puffing characteristics', Fuel, vol. 208, pp. 30-40.View/Download from: UTS OPUS or Publisher's site
© 2017 Elsevier Ltd The droplet suspension technology was used under the condition of atmospheric pressure and 873 K. The n-butanol concentration ranged from 0% to 75% to investigate the effect of n-butanol concentration on the puffing characteristics of a n-butanol-fatty acid methyl esters (FAME) droplet. Experimental results showed that BUT25, BUT50 and BUT75 (BUT'XX' represented XX% n-butanol by mass fraction in the n-butanol-FAME blend) underwent three phases, namely the transient heating phase, fluctuation evaporation phase and equilibrium evaporation phase. The temperatures of BUT25, BUT50 and BUT75 were similar at the start and end of the transient heating phase. The duration of BUT75's transient heating phase was much longer than that of BUT25 and BUT50. Therefore, the evaporation cooling of BUT75 was the most prominent because the temperature growth rate of BUT75 was significantly less than that of BUT25 and BUT50. Furthermore, the fluctuation evaporation phase could be divided into the strong and weak fluctuation stages. The violent fluctuation was only observed in the strong fluctuation stage. The weak fluctuation stage was similar as the stable evaporation. The active rupture was found in the strong fluctuation stage and the passive rupture was found in the weak fluctuation stage. The active and passive ruptures were caused by the fast bubble expansion and surface evaporation respectively. In addition, many periodic processes were contained in the strong fluctuation stage. The similarity degree of the periodic process showed a slump and a gradual increase, which were caused by bubble expansion and droplet recovery respectively. The bubble expansion of BUT50 was greater than that of BUT75. Significant bubble expansion led to the violent deformation after bubble rupture. The recovery time of BUT50 was longer than that of BUT75. Therefore, the similarity degree of BUT50 exhibited a wavy structure and BUT75 displayed a comb-like structure in the strong fl...
Wang, Z, Wu, S, Huang, Y, Chen, Y, Shi, S, Cheng, X & Huang, R 2017, 'Evaporation and Ignition Characteristics of Water Emulsified Diesel under Conventional and Low Temperature Combustion Conditions', ENERGIES, vol. 10, no. 8.View/Download from: UTS OPUS or Publisher's site
Huang, Y, Hong, G & Zhou, J 2017, 'Numerical Modelling of Ethanol Direct Injection (EDI) Sprays of a Multi-Hole Injector under Non-Evaporating, Transition and Flash-Boiling Conditions', SAE Technical Papers, vol. 2017-October, no. October.View/Download from: UTS OPUS or Publisher's site
Copyright © 2017 SAE International. Ethanol direct injection (EDI) has great potential in facilitating the downsizing technologies in spark ignition engines due to its strong anti-knock ability. The fuel temperature may vary widely from non-evaporating to flash-boiling sprays in real engine conditions. In this study, a CFD spray model was developed in the ANSYS Fluent environment, which was capable to simulate the EDI spray and evaporation characteristics under non-evaporating, transition and flash-boiling conditions. The turbulence was modelled by the realizable k- model. The Rinzic heterogeneous nucleation model was applied to simulate the primary breakup droplet size at the nozzle exit. The secondary breakup process was modelled by the Taylor Analogy Breakup model. The evaporation process was modelled by the Convection/Diffusion Controlled Model. The droplet distortion and drag, collision and droplet-wall interaction were also included. The spray model was verified against the spray experimental results in a constant volume chamber. The developed spray model well simulated the EDI spray evolution and evaporation processes under non-evaporating, transition and flash-boiling conditions. The simulation results showed that the non-evaporating spray's characteristics were similar to those of the normal-evaporating spray in terms of spray structure and spray tip penetration. The spray plumes converged towards the middle one with the increase of fuel temperature and finally collapsed completely when the spray superheat degree was higher than 9 K. This was caused by the increased ambient air speed and stronger vortices entrained by the spray jet, and additionally by the significantly reduced droplet size. The EDI spray could be considered as non-evaporating when the fuel temperature was lower than 325 K at 1 bar. The evaporation rate increased slightly with the fuel temperature increased from 275 to 360 K, but significantly from 360 to 400 K. Although it reduced the ...
Huang, Y, Hong, G & Huang, R 2016, 'Effect of injection timing on mixture formation and combustion in an ethanol direct injection plus gasoline port injection (EDI plus GPI) engine', ENERGY, vol. 111, pp. 92-103.View/Download from: UTS OPUS or Publisher's site
Huang, Y & Hong, G 2016, 'Investigation of the effect of heated ethanol fuel on combustion and emissions of an ethanol direct injection plus gasoline port injection (EDI plus GPI) engine', ENERGY CONVERSION AND MANAGEMENT, vol. 123, pp. 338-347.View/Download from: UTS OPUS or Publisher's site
Huang, Y, Huang, S, Huang, R & Hong, G 2016, 'Spray and evaporation characteristics of ethanol and gasoline direct injection in non-evaporating, transition and flash-boiling conditions', ENERGY CONVERSION AND MANAGEMENT, vol. 108, pp. 68-77.View/Download from: UTS OPUS or Publisher's site
Huang, Y, Hong, G & Huang, R 2015, 'Numerical investigation to the dual-fuel spray combustion process in an ethanol direct injection plus gasoline port injection (EDI+GPI) engine', Energy Conversion and Management, vol. 92, pp. 275-286.View/Download from: UTS OPUS or Publisher's site
Ethanol direct injection plus gasoline port injection (EDI + GPI) is a new technology to make the use of ethanol fuel more effective and efficient in spark ignition engines. Multi-dimensional computational fluid dynamics modelling was conducted on an EDI + GPI engine in both single and dual fuelled conditions. The in-cylinder flow field was solved in the realizable k turbulence model with detailed engine geometry. The temporal and spatial distributions of the liquid and vapour fuels were simulated with the spray breakup and evaporation models. The combustion process was modelled with the partially premixed combustion concept in which both mixture fraction and progress variable were solved. The three-dimensional and five-dimensional presumed Probability Density Function (PDF) look-up tables were used to model the single-fraction-mixture and two-fraction-mixture turbulence–chemistry interactions respectively. The model was verified by comparing the numerical and experimental results of spray pattern and cylinder pressure. The simulation results showed that the combustion process of EDI + GPI dual-fuelled condition was partially premixed combustion because of the low evaporation rate of ethanol spray in low temperature environment before combustion. Compared with GPI only, the higher flame speed of ethanol fuel contributed to the greater pressure rise rate and maximum cylinder pressure in EDI + GPI condition, which consequently resulted in higher power output and thermal efficiency. The lower adiabatic flame temperature of ethanol, partially premixed combustion mode and stronger cooling effect of ethanol direct injection in EDI + GPI led to the reduced combustion temperature which contributed to the decrease of NO emission. Among these three factors, the lower adiabatic flame temperature and partially premixed combustion mode were the dominating factors that resulted in the low combustion temperature of EDI + GPI. On the other hand, CO and HC emissions increased b...
Huang, Y, Hong, G & Huang, R 2015, 'Investigation to charge cooling effect and combustion characteristics of ethanol direct injection in a gasoline port injection engine', Applied Energy, vol. 160, pp. 244-254.View/Download from: UTS OPUS or Publisher's site
Huang, Y, Huang, S, Deng, P, Huang, R & Hong, G 2014, 'The Effect of Fuel Temperature on the Ethanol Direct Injection Spray Characteristics of a Multi-hole Injector', SAE International Journal of Fuels and Lubricants, vol. 7, no. 3, pp. 792-802.View/Download from: UTS OPUS or Publisher's site
Ethanol direct injection (EDI) is a new technology to use ethanol fuel more efficiently in spark ignition engines. Fuel temperature is one of the key factors which determine the evaporation process of liquid fuel spray, and consequently influence the combustion and emission generation of the engine. To better understand the mixture formation process of the EDI spray and provide experimental data for engine modelling, experiments were conducted in a constant volume chamber in engine-like conditions. The high speed Shadowgraphy imaging technique was used to capture the ethanol spray behaviours. The experiments covered a wide range of fuel temperature, ranged from 275 K (non-evaporating) to 400 K (flash-boiling). Particularly the transition of the ethanol spray from normal-evaporating to flash-boiling was investigated. The temporal Shadowgraphy spray images, spray tip penetration, angle and projected area were applied to evaluate the
evaporation of EDI spray under different fuel temperature conditions. The results showed that the non-evaporating spray's characteristics were similar to the normal-evaporating sprays' in terms of spray tip penetration, angle and projected area. When the fuel temperature increased from 350 K to flash-boiling spray, the spray angle and projected area reduced significantly, but the spray tip penetration increased. Increasing the fuel temperature from 275 K to 325 K did not cause significant increase of the evaporating rate, but with further increase of the fuel temperature, the ethanol spray's evaporation became faster. The transition temperature at which the ethanol spray collapsed at atmospheric pressure was between 355 K and 360 K.
Organ, BD, Huang, Y, Zhou, J, Hong, G, Yam, YS & Chan, E 2018, 'Emission Performance of LPG Vehicles by Remote Sensing Technique in Hong Kong', SAE Technical Papers.View/Download from: Publisher's site
© 2018 SAE International. All Rights Reserved. Since 1st September 2014 the Hong Kong Environmental Protection Department (HKEPD) has been utilising a Dual Remote Sensing technique to monitor the emissions from gasoline and liquified petroleum gas (LPG) vehicles for identifying high emitting vehicles running on road. Remote sensing measures and determines volume ratios of the emission gases of HC, CO and NO against CO2, which are used for determining if a vehicle is a high emitter. Characterisation of each emission gas is shown and its potential to identify a high emitter is established. The data covers a total of about 2,200,000 LPG vehicle emission measurements taken from 14 different remote sensing units. It was collected from 6th January 2012 to 20th April 2017 across a period before and after the launch of the Remote Sensing programme for evaluating the performance of the programme. The results show that the HKEPD Remote Sensing programme is very effective to detect high emitting vehicles and reduce on-road vehicle emissions. The average measured remote sensing emissions of HC, CO and NO reduced by 53.6%, 29.6% and 50.3% respectively from 2013 (the year before the launch of the programme) to 2015 (the year after the launch of the programme).
Ng, CY, Huang, Y, Hong, G, Zhou, J, Surawski, N, Ho, J & Chan, E 2018, 'Effects of an On-Board Safety Device on the Emissions and Fuel Consumption of a Light Duty Vehicle', SAE Technical Papers.View/Download from: UTS OPUS or Publisher's site
© 2018 SAE International. All Rights Reserved. Vehicle emissions and fuel consumption are significantly affected by driving behavior. Many studies of eco-driving technology such as eco-driving training, driving simulators and on-board eco-driving devices have reported potential reductions in emissions and fuel consumption. Use of on-board safety devices is mainly for safety, but also affects vehicle emissions and fuel consumption. In this study, an on-board safety device was installed to alert the driver and provide several types of warning to the driver (e.g. headway monitoring warning, lane collision warning, speed limit warning, etc.) to improve driving behavior. A portable emissions measurement system (PEMS) was used to measure vehicle exhaust concentrations, including hydrocarbons (HC), carbon monoxide (CO), carbon dioxide (CO2) and nitrogen oxides (NOx). The driving parameters including vehicle speed, acceleration and position were also recorded. A specific test route was designed for the experiment to investigate both urban and highway conditions. The driving parameters and emissions data were compared before and after the installation of the on-board safety device with the same driver. The Vehicle Specific Power (VSP) methodology was applied to evaluate the effects of the on-board safety device on driving behavior. The results indicated that the device had a positive effect on the driver's driving behavior. The percentage of time spent on excessive speeding and strong acceleration decreased from 22.2% to 14.7%. As a result, an average reduction of 25% in fuel consumption was observed. In addition, HC, CO2 and NOx emissions showed a reduction of 57%, 25% and 9% respectively. However, CO emission was increased and the time spent on idling showed no change with the installation of the device.
Huang, Y, Hong, G & Huang, R 2015, 'The Effect of Volume Ratio of Ethanol Directly Injected in a Gasoline Port Injection Spark Ignition Engine', 10th Asia-Pacific Conference on Combustion, Beijing China.View/Download from: UTS OPUS
Ethanol direct injection plus gasoline port injection (EDI+GPI) represents a more efficient and flexible way to utilize ethanol fuel in spark ignition (SI) engines. The greater cooling effect and higher octane number of ethanol fuel make it possible to implement engine downsizing while avoiding knock in SI engines. In this paper, experiments were conducted on a single-cylinder 0.25L-displacement SI engine equipped with an EDI+GPI dual-injection fuel system. The engine was run at medium load (IMEP 6.3-7.0 bar) and stoichiometric fuel/air ratio. The ethanol ratio by volume varied from 0% (GPI only) to 100% (EDI only). Experimental results showed that the IMEP and thermal efficiency increased with the increase of ethanol ratio up to an ethanol ratio of 69% at 3500 RPM and 76% at 4000 RPM. With ethanol ratio greater than 69% or 76%, the IMEP and thermal efficiency reduced with the increased ethanol ratio. For engine exhaust gas emissions, the CO and HC emissions increased and NO decreased with the increase of ethanol ratio from 0% to 100%.
Huang, Y & Hong, G 2015, 'An Investigation of the Performance of a Gasoline Spark Ignition Engine Fuelled with Hot Ethanol Direct Injection', Proceedings of the Australian Combustion Symposium, the Combustion Institute, Proceedings of the Australian Combustion Symposium, The Combustion Institute, Melbourne, Australia, pp. 204-207.View/Download from: UTS OPUS
Ethanol direct injection (EDI) is a promising technology to address the issue of knock in downsized spark ignition (SI) engines
due to the strong cooling effect of EDI and ethanol's large octane number. However, the evaporation rate of ethanol is lower than that
of gasoline fuel because of its low volatility (saturation vapour pressure) in low temperature conditions and large enthalpy of
vaporization. This might have caused the increased HC and CO emissions in an ethanol direct injection plus gasoline port injection
(EDI+GPI) engine when EDI was applied. To address this issue, the combustion and emission performance of an EDI+GPI engine
fuelled with hot ethanol fuel was experimentally investigated in the present study. The experiments were conducted on a 249 cc single
cylinder SI engine at medium load (IMEP 6.0-6.3 bar) and stoichiometric fuel/air ratio condition. The injected ethanol fuel
temperature ranged from 45 (no fuel heating) to 105 (flash-boiling spray) with an increment of 15 . Experimental results
showed that the IMEP decreased slightly with the increase of ethanol fuel temperature. However, the ISCO and ISHC emissions
decreased significantly and ISNO increased moderately with the increase ethanol fuel temperature.
Huang, Y, Hong, G & Huang, R 2014, 'Numerical Investigation to the Effect of Ethanol/Gasoline Ratio on Charge Cooling in an EDI+GPI Engine', SAE 2014 International Powertrain, Fuels & Lubricants Meeting, SAE Powertrains, Fuels, and Lubricants Meeting, SAE International, Birmingham, UK, pp. 1-10.View/Download from: UTS OPUS or Publisher's site
The work reported in this paper contributes to understanding the effects of ethanol/gasoline ratio on mixture formation and cooling effect which are crucial in the development of EDI+GPI engine. The spray simulations were carried out using a commercial CFD code. The model was verified by comparing the numerical and experimental results of spray shapes in a constant volume chamber and cylinder pressure in an EDI+GPI research engine. The verified model was used to investigate the fuel vaporization and mixture formation of the EDI+GPI research engine. The effect of the ethanol/gasoline ratio on charge cooling has been studied. Compared with GPI only, EDI+GPI demonstrated stronger effect on charge cooling by decreased in-cylinder temperature. However, the cooling effect was limited by the low evaporation rate of the ethanol fuel due to its lower saturation vapour pressure than gasoline's in low temperature conditions. The cooling effect of EDI increased with the increase of ethanol/gasoline ratio until the ratio reached 58% (by volume). Further increase of ethanol/gasoline ratio did not improve the cooling effect, but left more liquid ethanol droplets in the combustion chamber by the time of spark. This could lead to incomplete combustion and explained the increased CO and HC emissions with the increase of ethanol content as reported in the experiments. The cooling potential and the completeness of ethanol evaporation were two completing factors that determine the final cooling effect of EDI. This implied the existence of ethanol/gasoline ratio 40-50% which can optimize the cooling effect and combustion performance.
Huang, Y & Hong, G 2014, 'Development of a Numerical Model for Investigating the EDI+GPI Engine', 19th Australasian Fluid Mechanics Conference, Australasian Fluid Mechanics Conference, 19th Australasian Fluid Mechanics Conference, Melbourne, Australia.View/Download from: UTS OPUS
This paper reports the development of a CFD model for investigating the ethanol direct injection plus gasoline port injection (EDI+GPI) engine. The model was developed using the commercial CFD code ANSYS FLUENT as a solver. The computational domain was meshed based on the scanned geometry of the cylinder head. Realizable k- turbulence model was used to simulate the in-cylinder flows. The Eulerian-Lagrangian approach was used to model the evolution of the fuel sprays. The dual-fuel combustion process was modelled by the Extended Coherent Flame Model (ECFM) in the partially premixed combustion concept. A five-dimensional presumed Probability Density Function (PDF) look-up table was used to model the dual-fuel turbulence-chemistry interactions. The model was verified by the good agreement between the numerical and experimental results of spray shapes in a constant volume chamber and cylinder pressure on the EDI+GPI research engine. Sample simulation results showed that the model was capable to simulate the spray combustion process of the EDI+GPI engine and meet the needs of the investigation.
Huang, Y, Huang, S, Huang, R & Hong, G 2014, 'Macroscopic and Microscopic Characteristics of Ethanol and Gasoline Sprays', Australasian Fluid Mechanics Website, Australasian Fluid Mechanics Conference, 19th Australasian Fluid Mechanics Conference, Melbourne, Australia, pp. 1-4.View/Download from: UTS OPUS
This paper reports the macroscopic and microscopic characteristics of ethanol and gasoline direct injection sprays from a multi-hole injector. The spray experiments were conducted in a constant volume chamber in atmospheric condition (1 bar and 300 K ambient condition). Compressed nitrogen was used to pressurize the injection pressure which was 6.0 MPa. The injection pulse width was 2.0 ms. The high speed Shadowgraphy imaging technique with a speed of 20000 fps @ 608×288 pixels was used to capture the macroscopic spray characteristics. Based on that, the high magnification imaging of the ethanol and gasoline sprays close to the nozzle exit was conducted with the same flash and camera but with an AFTVision ZL0911 microscope. In order to capture the first fuel seen from the nozzle exit, the camera speed was increased to 50000 fps @ 240×88 pixels. Results showed that the macroscopic characteristics of ethanol and gasoline sprays were rather similar in terms of spray tip penetration, spray angle and spray projected area in spite of the differences in physical properties. However, the magnified spray images at the nozzle exit showed that ethanol spray had a larger and sheet-like ligaments at the end of injection than gasoline spray did due to ethanol's larger surface tension and viscosity. It may imply that the fuel properties only have significant effect on the spray during the primary breakup process, but not on the secondary breakup process.
Huang, Y, Hong, G, Cheng, X & Huang, R 2013, 'Investigation to Charge Cooling Effect of Evaporation of Ethanol Fuel Directly Injected in a Gasoline Port Injection Engine', SAE/KSAE 2013 Powertrains, Fuels & Lubricants Meeting, SAE Powertrains, Fuels, and Lubricants Meeting, SAE International, Seoul, Korea, pp. 1-13.View/Download from: UTS OPUS or Publisher's site
Ethanol direct injection plus gasoline port injection (EDI+GPI) is a new technology to make the use of ethanol fuel more effective and efficient in spark ignition engines. It takes the advantages of ethanol fuel, such as its greater latent heat of vaporization than that of gasoline fuel, to enhance the charge cooling effect and consequently to increase the compression ratio and improve the engine thermal efficiency. Experimental investigation has shown improvement in the performance of a single cylinder spark ignition engine equipped with EDI+GPI. It was inferred that the charge cooling enhanced by EDI played an important role. To investigate it, a CFD model has been developed for the experimentally tested engine. The Eulerian-Lagrangian approach and Discrete Droplet Model were used to model the evolution of the fuel sprays. The model was verified by comparing the numerical and experimental results of cylinder pressure during the intake and compression strokes. Mesh density and time step sensitivities have been tested. The verified model was used to investigate the charge cooling effect of EDI in terms of spatial and temporal distributions of cylinder temperature and fuel vapor fraction. Compared with GPI only, EDI+GPI demonstrated stronger effect on charge cooling by decreased in-cylinder temperature. The cooling effect was limited by the low evaporation rate of the ethanol fuel due to its lower saturation vapor pressure than gasoline's in low temperature conditions.