Potential of Large Output Power, High Thermal Efficiency, Near-zero NOx Emission, Supercharged, Lean-burn, Hydrogen-fuelled, Direct Injection Engines

Nakagawa, Kenji; Yamane, Kimitaka; Ohira, Tetsuya

doi:10.1016/j.egypro.2012.09.053

Cited by 16 publications

(5 citation statements)

References 1 publication

Supporting

Mentioning

Contrasting

Order By: Relevance

“…U s is considerably greater for hydrogen than for methane (by about 3 times) due to the faster rate of acoustic waves propagation in hydrogen; see equation (20). Figure 9 also illustrates that for hydrogen jetting, θ is considerably larger than for methane.…”

Section: Mixing Characteristicsmentioning

confidence: 93%

See 1 more Smart Citation

Large eddy simulation of highly turbulent under-expanded hydrogen and methane jets for gaseous-fuelled internal combustion engines

Hamzehloo¹,

Aleiferis²

2014

International Journal of Hydrogen Energy

View full text Add to dashboard Cite

Burning hydrogen in conventional internal combustion (IC) engines is associated with zero carbon-based tailpipe exhaust emissions. In order to obtain high volumetric efficiency and eliminate abnormal combustion modes such as preignition and backfire, in-cylinder direct injection (DI) of hydrogen is considered preferable for a future generation of hydrogen IC engines. However, hydrogen's low density requires high injection pressures for fast hydrogen penetration and sufficient in-cylinder mixing. Such pressures lead to chocked flow conditions during the injection process which result in the formation of turbulent under-expanded hydrogen jets. In this context, fundamental understanding of the under-expansion process and turbulent mixing just after the nozzle exit is necessary for the successful design of an efficient hydrogen injection system and associated injection strategies. The current study used large-eddy simulation (LES) to investigate the characteristics of hydrogen under-expanded jets with different nozzle pressure ratios (NPR), namely 8.5, 10, 30 and 70. A test case of methane injection with NPR=8.5 was also simulated for direct comparison with the hydrogen jetting under the same NPR. The near-nozzle shock structure, the geometry of the Mach disk and reflected shock angle, as well as the turbulent shear layer were all captured in very good agreement with data available in the literature. Direct comparison between hydrogen and methane fuelling showed that the ratio of the specific heats had a noticeable effect on the near-nozzle shock structure and dimensions of the Mach disk. It was observed that with methane, mixing did not occur before the Mach disk, whereas with hydrogen high levels of momentum exchange and mixing appeared at the boundary of the jet. This was believed to be the effect of the high turbulence fluctuations at the nozzle exit of the hydrogen jet which triggered Gortler vortices. Generally, the primary mixing was observed to occur after the location of the Mach disk and particularly close to the jet boundaries where large-scale turbulence played a dominant role. It was also found that NPR had significant effect on the mixture's local fuel richness. Finally, it was noted that applying higher injection pressure did not essentially increase the penetration length of the hydrogen jets and that there could be an optimum NPR that would introduce more enhanced mixing whilst delivering sufficient fuel in less time. Such an optimum NPR could be in the region of 100 based on the geometry and observations of the current study.3

show abstract

Section: Mixing Characteristicsmentioning

confidence: 93%

“…Assuming chocked condition at the nozzle exit (Ma=1), U 1 would be that of the speed of sound which, with the ideal gas assumption, was calculated as: (20) where the temperature at the nozzle exit (T 1 ) was defined as [53]:…”

Section: Simulation Setupmentioning

confidence: 99%

Large eddy simulation of highly turbulent under-expanded hydrogen and methane jets for gaseous-fuelled internal combustion engines

Hamzehloo¹,

Aleiferis²

2014

International Journal of Hydrogen Energy

View full text Add to dashboard Cite

show abstract

“…On raw emissions, NO x is H 2 -vehicles' primary emissions for the oxidation reaction of nitrogen under combustion temperature, and it can be simply reduced to a tiny amount by boosting leaning combustible mixtures associated with enhanced thermal efficiency [98,99]. Furthermore, EGR strategies are highly mature in China which is also an efficient solution of NO x emissions [49].…”

Section: Hydrogen Gas As Alternative Fuelmentioning

confidence: 99%

On reliability and flexibility of sustainable energy application route for vehicles in China

Sun

2015

Renewable and Sustainable Energy Reviews

View full text Add to dashboard Cite

“…The main advantage of hydrogen-fueled internal combustion engines (H2-ICEs) is the possibility of retrofitting current ICEs that use other fuels such as gasoline [15,16]. This environmental advantage is significant as it involves simply replacing some parts rather than creating an entire new powertrain for a vehicle [17].…”

Section: Introductionmentioning

confidence: 99%

Mild Hybrid Powertrain for Mitigating Loss of Volumetric Efficiency and Improving Fuel Economy of Gasoline Vehicles Converted to Hydrogen Fueling

Bibiloni,

Irimescu,

Martinez-Boggio

et al. 2024

Machines

View full text Add to dashboard Cite

The pursuit of sustainable and environmentally friendly transportation has led to the exploration of alternative fuel sources, among which hydrogen stands out prominently. This work delves into the potential of hydrogen fuel for internal combustion engines (ICEs), emphasizing its capacity to ensure the required performance levels while concurrently enhancing overall efficiency. The integration of a mild hybrid powertrain in a small size passenger car was considered for obtaining a twofold advantage: mitigating power loss due to low volumetric efficiency and increasing fuel economy. A comprehensive approach combining 0D/1D modeling simulations and experimental validations was employed on a gasoline-powered small size ICE, considering its conversion to hydrogen, and mild hybridization. Vehicle simulations were performed in AVL Cruise M and validated against experimental data. Various electric motors were scrutinized for a small size battery pack typical of mild hybrid vehicles. Furthermore, the paper assesses the potential range achievable with the hydrogen-powered hybrid vehicle and compares it with the range reported by the manufacturer for the original gasoline and pure electric version. In terms of global results, these modifications were found to successfully improve efficiency compared to baseline gasoline and hydrogen fueling. Additionally, performance gains were achieved, surpassing the capabilities of the original gasoline vehicle despite its intrinsic volumetric efficiency limitations when using hydrogen. Along with the conversion to hydrogen and thus zero-carbon tail-pipe emissions, incorporating a Start/Stop system, and the integration of mild hybrid technology with energy recuperation during braking, overall efficiency was enhanced by up to 30% during urban use. Furthermore, the hybridization implemented in the H2 version allows an autonomy comparable to that of the electric vehicle but with evident shorter refilling times. Specific aspects of the 48 V battery management are also scrutinized.

show abstract

Potential of Large Output Power, High Thermal Efficiency, Near-zero NOx Emission, Supercharged, Lean-burn, Hydrogen-fuelled, Direct Injection Engines

Cited by 16 publications

References 1 publication

Large eddy simulation of highly turbulent under-expanded hydrogen and methane jets for gaseous-fuelled internal combustion engines

Large eddy simulation of highly turbulent under-expanded hydrogen and methane jets for gaseous-fuelled internal combustion engines

On reliability and flexibility of sustainable energy application route for vehicles in China

Mild Hybrid Powertrain for Mitigating Loss of Volumetric Efficiency and Improving Fuel Economy of Gasoline Vehicles Converted to Hydrogen Fueling

Contact Info

Product

Resources

About