Dr. Yuhan Huang is currently a Postdoctoral Research Fellow in the School of Civil and Environmental Engineering at University of Technology Sydney (UTS). He received his Bachelor of Engineering at the Huazhong University of Science and Technology (HUST) in 2011 and Doctor of Philosophy at UTS in 2017. After that, he joined UTS as a Postdoctoral Research Fellow in February 2017, and then the Jockey Club Heavy Vehicle Emissions Testing and Research Centre in Hong Kong as a Visiting Research Fellow in November 2017.
His current research interests include vehicle emissions measurement, air quality, internal combustion engines, computational fluid dynamics (CFD), and renewable fuels.
Topic Editor of Atmosphere (IF=2.046), 10/2019 to present.
Member of Society of Automotive Engineers (SAE).
Reviewer for Energy Conversion and Management; Energy; Applied Energy; Applied Thermal Engineering; Science of the Total Environment; Environmental Pollution; Journal of Cleaner Production; Energy and Buildings; Experimental Thermal and Fluid Science; Energies; Sustainability; Atmosphere; Applied Sciences; SAE International Journal of Engines and SAE Technical Papers.
Can supervise: YES
- Air quality and vehicle emissions
- Internal combustion engines
- Computational fluids dynamics
- Spray and combustion
- Renewable energy
Altaee, A, Khlaifat, N, Zhou, J & Huang, Y 2020, 'Evaluation of wind resource potential using statistical analysis of probability density functions in New South Wales, Australia', Energy Sources, Part A: Recovery, Utilization, and Environmental Effects.View/Download from: Publisher's site
Wind energy is a vital part of Australia's energy mix. The first step in a wind power project at a particular site is to assess the wind resource potential and feasibility for wind energy production. Research on wind potential and statistical analysis has been done throughout the world. Currently, recent potential wind studies are lacking, especially in New South Wales (NSW), Australia. This study highlighted the feasibility of wind potential at four sites in NSW, namely Ballina, Merriwa, Deniliquin, and the Bega region. The type of wind speed distribution function dramatically affects the output of the available wind energy and wind turbine performance at a particular site. Therefore, the accuracy of four probability density functions was evaluated, namely Rayleigh, Weibull, Gamma, and Lognormal distributions. The outcomes showed Weibull provided the most accurate distribution. The annual average scale and shape parameters of Weibull distribution varied between 2.935-5.042 m/s and 1.137-2.096, respectively. The maximum shape and scale factors were at Deniliquin, while the minimum shape and scale factors were at Bega area. Assessment of power density indicated that Deniliquin had a marginal wind speed resource, while Ballina, Bega, and Merriwa had poor wind resources.
Huang, Y, Yu, Y, Yam, YS, Zhou, JL, Lei, C, Organ, B, Zhuang, Y, Mok, WC & Chan, EFC 2020, 'Statistical evaluation of on-road vehicle emissions measurement using a dual remote sensing technique', Environmental Pollution, vol. 267.View/Download from: Publisher's site
© 2020 Elsevier Ltd On-road remote sensing (RS) is a rapid, non-intrusive and economical tool to monitor and control the emissions of in-use vehicles, and currently is gaining popularity globally. However, a majority of studies used a single RS technique, which may bias the measurements since RS only captures a snapshot of vehicle emissions. This study aimed to use a unique dual RS technique to assess the characteristics of on-road vehicle emissions. The results show that instantaneous vehicle emissions are highly dynamic under real-world driving conditions. The two emission factors measured by the dual RS technique show little correlation, even under the same driving condition. This indicates that using the single RS technique may be insufficient to accurately represent the emission level of a vehicle based on one measurement. To increase the accuracy of identifying high-emitting vehicles, using the dual RS technique is essential. Despite little correlation, the dual RS technique measures the same average emission factors as the single RS technique does when a large number of measurements are available. Statistical analysis shows that both RS systems demonstrate the same Gamma distribution with ≥200 measurements, leading to converged mean emission factors for a given vehicle group. These findings point to the need for a minimum sample size of 200 RS measurements in order to generate reliable emission factors for on-road vehicles. In summary, this study suggests that using the single or dual RS technique will depend on the purpose of applications. Both techniques have the same accuracy in calculating average emission factors when sufficient measurements are available, while the dual RS technique is more accurate in identifying high-emitters based on one measurement only.
Khlaifat, N, Altaee, A, Zhou, J & Huang, Y 2020, 'A review of the key sensitive parameters on the aerodynamic performance of a horizontal wind turbine using computational fluid dynamics modelling', AIMS Energy, vol. 8, no. 3, pp. 493-524.View/Download from: Publisher's site
© 2020 the Author(s), licensee AIMS Press. Renewable energy technologies are receiving much attention to replacing power plants operated by fossil and nuclear fuels. Of all the renewable technologies, wind power has been successfully implemented in several countries. There are several parameters in the aerodynamic characteristics and design of the horizontal wind turbine. This paper highlights the key sensitive parameters that affect the aerodynamic performance of the horizontal wind turbine, such as environmental conditions, blade shape, airfoil configuration and tip speed ratio. Different turbulence models applied to predict the flow around the horizontal wind turbine using Computational Fluid Dynamics modeling are reviewed. Finally, the challenges and concluding remarks for future research directions in wind turbine design are discussed.
Organ, B, Huang, Y, Zhou, JL, Yam, Y-S, Mok, W-C & Chan, EFC 2020, 'Simulation of engine faults and their impact on emissions and vehicle performance for a liquefied petroleum gas taxi', SCIENCE OF THE TOTAL ENVIRONMENT, vol. 716.View/Download from: Publisher's site
Xie, J, Liu, CH, Mo, Z, Huang, Y & Mok, WC 2020, 'Near-field dynamics and plume dispersion after an on-road truck: Implication to remote sensing', Science of the Total Environment, vol. 748.View/Download from: Publisher's site
© 2020 Elsevier B.V. Apart from the aerodynamic performance (efficiency and safety), the wake after an on-road vehicle substantially influences the tailpipe pollutant dispersion (environment). Remote sensing is the most practicable measures for large-scale emission control. Its reliability, however, is largely dictated by how well the complicated vehicular flows and instrumentation constraint are tackled. Specifically, the broad range of motion scales and the short sampling duration (less than 1 s) are the most prominent ones. Their impact on remote sensing has not been studied. Large-eddy simulation (LES) is thus employed in this paper to look into the dynamics and the plume dispersion after an on-road heavy-duty truck at speed U∞ so as to elucidate the transport mechanism, examine the sampling uncertainty and develop the remedial measures. A major recirculation of size comparable to the truck height h is induced collectively by the roof-level prevailing flows, side entrainment and underbody wall jet. The tailpipe is enclosed by dividing streamlines so the plume is carried back to the truck right after emission. The recirculation augments the pollutant mixing, resulting in a more homogeneous pollutant distribution together with a rather high fluctuating concentration (over 20% of the time-averaged concentrations). The plume ascends mildly before being purged out of the major recirculation to the far field by turbulence, leading to a huge reduction in pollutant concentration (an order of magnitude) outside the near wake. In the far-field, the plume is higher than the tailpipe and disperses in a conventional Gaussian distribution manner. Under this circumstance, a sampling duration for remote sensing longer than h/U∞ would be prone to underestimating the tailpipe emission.
Zhuang, Y, Chi, H, Huang, Y, Teng, Q, He, B, Chen, W & Qian, Y 2020, 'Investigation of water spray evolution process of port water injection and its effect on engine performance', Fuel, vol. 282.View/Download from: Publisher's site
© 2020 Elsevier Ltd In this study, a 1.5L turbocharged gasoline direct injection (GDI) engine was modified by installing a port water injection (PWI) system adjacent to the intake valve to simulate the "quasi-direct" water injection. Experiments was performed at 1500 rpm wide throttle open (WOT) condition to investigate the effect of PWI on knock suppression, and 4850 rpm WOT condition to test the removal of fuel enrichment through PWI. Then, numerical simulation was conducted to investigate the water spray evolution process and subsequent influence on mixture formation. The experimental results showed that PWI could effectively suppress knock and decrease combustion temperature. Therefore, at 4850 rpm WOT condition, the engine was able to operate at a stoichiometric air/fuel ratio with moderate advancement of spark timing. The combined effect finally resulted in nearly 6% thermal efficiency improvement. At 1500 rpm WOT, 3.8% efficiency gain was achieved solely due to knock mitigation. Nitrogen oxides (NOx), soot and hydrocarbon (HC) emissions also showed a decreasing trend with the increase of water injection amount. The simulation results indicated that about 80% of total injected water collided on the inner surface of the intake port which became the major source of water vapor. The portion of water vaporized in the air is small. Sufficient time was important for intake port water film evaporation. PWI also resulted in in-cylinder wall wetting. The in-cylinder water wall wetting in 4850 rpm was sober than that at 1500 rpm due to stronger intake air motion and higher cylinder temperature. Although port water injection imposes limited impacts on the whole in-cylinder equivalent ratio, it can induce part fuel-rich zones inside the combustion chamber.
Zhuang, Y, Sun, Y, Huang, Y, Teng, Q, He, B, Chen, W & Qian, Y 2020, 'Investigation of water injection benefits on downsized boosted direct injection spark ignition engine', FUEL, vol. 264.View/Download from: Publisher's site
The performance of a wind turbine is profoundly affected by wind conditions. Small wind turbines usually achieve the demand for electricity in rural areas. The shape of the blade greatly influences the performance of the wind turbine. The present study aims to optimize the performance of a 20 kW horizontal-axis wind turbine (HAWT) under local wind conditions at Deniliquin, New South Wales, Australia. ANSYS Fluent was used to investigate the aerodynamic performance of the 20 KW HAWT. The effects of four Reynolds Averaged Navier Stokes (RANS) turbulence models on predicting the flow over the wind turbine under separation condition were examined. Transition SST model had the best agreement with NREL CER data, which was used to investigate the mechanical output at different rotational speeds and variable pitch angles. Then the aerodynamic shape of the rotor of the wind turbine was optimized to maximize the annual energy production (AEP) in the Deniliquin region. Statistical wind analysis was applied to define the Weibull function and scale parameters which were 2.096 and 5.042 m/s, respectively. HARP_Opt was enhanced with design variables concerning the shape of the blade, rated rotational speed, and pitch angle. Pitch angle remained at 0ᵒ while the rising wind speed improved rotor speed to 148.4482 rpm at rated speed. This optimization improved the AEP rate by 9.068% when compared to the original NREL design.
Huang, Y, Mok, W-C, Yam, Y-S, Zhou, JL, Surawski, NC, Organ, B, Chan, EFC, Mofijur, M, Mahlia, TMI & Ong, HC 2020, 'Evaluating in-use vehicle emissions using air quality monitoring stations and on-road remote sensing systems', SCIENCE OF THE TOTAL ENVIRONMENT, vol. 740.View/Download from: Publisher's site
Huang, Y, Ng, ECY, Surawski, NC, Yam, Y-S, Mok, W-C, Liu, C-H, Zhou, JL, Organ, B & Chan, EFC 2020, 'Large eddy simulation of vehicle emissions dispersion: Implications for on-road remote sensing measurements', ENVIRONMENTAL POLLUTION, vol. 259.View/Download from: Publisher's site
Huang, Y, Surawski, NC, Yam, Y-S, Lee, CKC, Zhou, JL, Organ, B & Chan, EFC 2020, 'Re-evaluating effectiveness of vehicle emission control programmes targeting high-emitters', NATURE SUSTAINABILITY.View/Download from: Publisher's site
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
© 2018 Elsevier Ltd Dual injection of ethanol fuel (DualEI) has been in development. DualEI has the potential in increasing the compression ratio and thermal efficiency of spark ignition engines by taking the advantages of ethanol fuel properties and the direct injection. This paper reports an experimental investigation of the effect of direct injection (DI) timing associated with spark timing on the performance of a small DualEI engine. Experiments were conducted with fixed port injection timing and varied DI timing before (early) and after (late) the intake valve closed at 3500 RPM and two load conditions. Results show that the engine performance is enhanced by early DI timing, although the variation of IMEP and indicated thermal efficiency with DI timing is not significant either with early DI timing or in most of the tested conditions with late DI timing. Only in the medium load condition when the DI timing is retarded from 80 to 60 CAD bTDC, the IMEP and thermal efficiency significantly reduced by about 16% due to the increased initial combustion duration, resulting in reduced flame speed and increased combustion instability. The results also show different effects of early and late DI timing associated with the spark timing on engine emissions. With late DI timing, the engine emissions of CO and NO increase with the advance of late DI timing and spark timing. With early DI timing, the engine emissions increase with the advance of spark timing. However, the variation of engine emissions with early DI timing is more complicated than that late.
Nguyen, KT, Nguyen, HM, Truong, CK, Ahmed, MB, Huang, Y & Zhou, JL 2019, 'Chemical and microbiological risk assessment of urban river water quality in Vietnam.', Environmental Geochemistry and Health: official journal of the Society for Environmental Geochemistry and Health, vol. 41, no. 6, pp. 2559-2575.View/Download from: Publisher's site
The contamination and risk by nutrients (NH4+, NO2-, NO3- and PO43-), COD, BOD5, coliform and potentially toxic elements (PTEs) of As, Cd, Ni, Hg, Cu, Pb, Zn and Cr were investigated in urban river (Nhue River), Vietnam during 2010-2017. The extensive results demonstrated that concentrations of these contaminants showed significant spatial and temporal variations. The Nhue River was seriously polluted by NH4+ (0.025-11.28 mg/L), PO43- (0.17-1.72 mg/L), BOD5 (5.8-179.6 mg/L), COD (1.4-239.8 mg/L) and coliform (1540-326,470 CFU/100 mL); moderately polluted by As (0.2-131.15 μg/L) and Hg (0.11-4.1 μg/L); and slightly polluted by NO2- (0.003-0.33 mg/L) and Cd (2.1-18.2 μg/L). The concentrations of NH4+, PO43-, COD, BOD5 and coliform frequently exceeded both drinking water guidelines and irrigation water standards. Regarding PTEs, As, Cd and Hg concentrations were frequently higher than the regulatory limits. Human health risks of PTEs were evaluated by estimating hazard index (HI) and cancer risk through ingestion and dermal contacts for adults and children. The findings indicated that As was the most important pollutant causing both non-carcinogenic and carcinogenic concerns. The non-carcinogenic risks of As were higher than 1.0 at all sites for both adults (HI = 1.83-7.4) and children (HI = 2.6-10.5), while As posed significant carcinogenic risks for adults (1 × 10-4-4.96 × 10-4). A management strategy for controlling wastewater discharge and protecting human health is urgently needed.
Wang, B, Lau, YS, Huang, Y, Organ, B, Lee, SC & Ho, KF 2019, 'Investigation of factors affecting the gaseous and particulate matter emissions from diesel vehicles', Air Quality, Atmosphere and Health, vol. 12, no. 9, pp. 1113-1126.View/Download from: Publisher's site
© 2019, Springer Nature B.V. This study presents a detailed investigation of diesel vehicle emissions utilizing chassis dynamometer testing. The recruited vehicle fleet consists of 15 in-use diesel vehicles, spanning a wide range of emission standards, engine sizes, weight, model year, etc. The real-time emission concentrations of nitrogen oxides (NOx), total hydrocarbons (THC), carbon monoxide (CO) and carbon dioxide (CO2), and the mass of particulate matter (PM) collected on filters are measured and used to calculate the vehicle emission factors (EFs) under various driving conditions. Results show that in general EFs of NOx, CO, THC, and PM of the recruited fleet span a wide range of values (NOx 0.80 ± 0.34 to 60.28 ± 2.94 g kg−1; THC 0.10 ± 0.04 to 5.28 ± 1.28 g kg−1; CO below detection limits to 24.01 ± 8.48 g kg−1; PM below detection limits to 2.47 ± 1.22 g kg−1). Further data analysis shows that the implementation of a higher emission standard has a significant effect on reducing the emission of pollutants, except for NOx. Driving conditions are also important factors affecting the EFs. Besides, statistical analysis shows a significant correlation between EFs of NOx with the testing weight and the maximum engine power of the vehicle. Further investigation is recommended to explore the effect of maintenance of the vehicles to the vehicular emission.
Zhuang, Y, Zhu, G, Gong, Z, Wang, C & Huang, Y 2019, 'Experimental and numerical investigation of performance of an ethanol-gasoline dual-injection engine', ENERGY, vol. 186.View/Download from: Publisher's site
Huang, Y, Ng, ECY, Yam, Y-S, Lee, CKC, Surawski, NC, Mok, W-C, 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, vol. 184, pp. 521-529.View/Download from: Publisher's site
Huang, Y, Organ, B, Zhou, JL, Surawski, NC, Yam, Y-S & Chan, EFC 2019, 'Characterisation of diesel vehicle emissions and determination of remote sensing cutpoints for diesel high-emitters.', Environmental Pollution, vol. 252, no. Part A, pp. 31-38.View/Download from: Publisher's site
Diesel vehicles are a major source of air pollutants in cities and have caused significant health risks to the public globally. This study used both on-road remote sensing and transient chassis dynamometer to characterise emissions of diesel light goods vehicles. A large sample size of 183 diesel vans were tested on a transient chassis dynamometer to evaluate the emission levels of in-service diesel vehicles and to determine a set of remote sensing cutpoints for diesel high-emitters. The results showed that 79% and 19% of the Euro 4 and Euro 5 diesel vehicles failed the transient cycle test, respectively. Most of the high-emitters failed the NO limits, while no vehicle failed the HC limits and only a few vehicles failed the CO limits. Vehicles that failed NO limits occurred in both old and new vehicles. NO/CO2 ratios of 57.30 and 22.85 ppm/% were chosen as the remote sensing cutpoints for Euro 4 and Euro 5 high-emitters, respectively. The cutpoints could capture a Euro 4 and Euro 5 high-emitter at a probability of 27% and 57% with one snapshot remote sensing measurement, while only producing 1% of false high-emitter detections. The probability of high-emitting events was generally evenly distributed over the test cycle, indicating that no particular driving condition produced a higher probability of high-emitting events. Analysis on the effect of cutpoints on real-driving diesel fleet was carried out using a three-year remote sensing program. Results showed that 36% of Euro 4 and 47% of Euro 5 remote sensing measurements would be detected as high-emitting using the proposed cutpoints.
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: 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.
Organ, B, Huang, Y, Zhou, JL, Surawski, NC, Yam, Y-S, Mok, W-C & Hong, G 2019, 'A remote sensing emissions monitoring programme reduces emissions of gasoline and LPG vehicles', ENVIRONMENTAL RESEARCH, vol. 177.View/Download from: 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: 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, 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: Publisher's site
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: 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.
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: 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: 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, 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: 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: Publisher's site
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: 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 2.49 L and early 2.98 L 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.
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: Publisher's site
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: 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...
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: Publisher's site
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: 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: Publisher's site
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: 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: 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−ε 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, 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: 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.
Huang, Y, Zhou, JL, Yu, Y, Mok, W-C, Lee, CFC & Yam, Y-S, 'Uncertainty in the Impact of the COVID-19 Pandemic on Air Quality in Hong Kong, China', Atmosphere, vol. 11, no. 9, pp. 914-914.View/Download from: Publisher's site
Strict social distancing rules are being implemented to stop the spread of COVID-19 pandemic in many cities globally, causing a sudden and extreme change in the transport activities. This offers a unique opportunity to assess the effect of anthropogenic activities on air quality and provides a valuable reference to the policymakers in developing air quality control measures and projecting their effectiveness. In this study, we evaluated the effect of the COVID-19 lockdown on the roadside and ambient air quality in Hong Kong, China, by comparing the air quality monitoring data collected in January–April 2020 with those in 2017–2019. The results showed that the roadside and ambient NO2, PM10, PM2.5, CO and SO2 were generally reduced in 2020 when comparing with the historical data in 2017–2019, while O3 was increased. However, the reductions during COVID-19 period (i.e., February–April) were not always higher than that during pre-COVID-19 period (i.e., January). In addition, there were large seasonal variations in the monthly mean pollutant concentrations in every year. This study implies that one air pollution control measure may not generate obvious immediate improvements in the air quality monitoring data and its effectiveness should be evaluated carefully to eliminate the effect of seasonal variations.
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, International Powertrains, Fuels & Lubricants Meeting, SAE International, Germany.View/Download from: 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 & 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.View/Download from: 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-μ 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 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.
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 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.
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 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.
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-ε 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, 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: 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, 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.
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: 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.