Fast Combustion Research Articles

Performance Analysis of a Dual-Fuel Sugar Based Solid Rocket Propellant

The effects of dual-fuel on improving the ballistic efficiency of a low energy sugar-based solid rocket propellant were investigated in this paper. This was achieved by establishing a threshold proportion of sucrose to sorbitol that provided the highest ballistic efficiency, using a beam load cell (model single-point 2,000 kg linearly defined by 0-20 kN force, with ±.005 percent precision). Seven different propellant formulations were prepared, loaded into the rocket motor and tested for performance. The major performance parameters of interest were the thrust, total impulse, burn time, delivered specific impulse, delivered characteristic velocity, and the chamber pressure. The formulations tested were potassium nitrate–sucrose propellant (65% KNO3 and 35% sucrose (C12H22O11)) (KNSU); potassium nitrate-sorbitol propellant (65% KNO3 and 35% sorbitol (C6H14O6)) (KNSB); modified potassium nitrate-sucrose propellant (65% KNO3, 32% sucrose (C12H22O11)), and 3% carbon (C) (MODKNSU); potassium nitrate-sucrose-sorbitol propellant (65% KNO3, 25% sucrose (C12H22O11)), and 10% sorbitol (C6H14O6) (KNERK); potassium nitrate-sucrose-sorbitol-carbon propellant (65% KNO3, 24% sucrose (C12H22O11), 10% sorbitol (C6H14O6), and 1% carbon (C)) (MODKNERK); and finally a propellant made from KNO3, sucrose (C12H22O11), sorbitol (C6H14O6), carbon (C) and iron II oxide(Fe2O3) combinations in 65, 30, 3, 1, 1% proportion respectively. The novel result obtained from these experiments was applied to boost the performance of a KNSB rocket propellant motor during a rocket launch experiment. Both static and dynamic rocket motor internal ballistic parameters were then compared. The measured delivered motor average thrust and the effective propellant burn times were recorded as: (164.15N, 3.97s); (102.95N, 6.53s); (65.66N, 9.38s); (79.09N, 3.77s); (243.98N, 3.77s) and (92.6N, 5.89s) respectively. The MODKNERK, was established to produce a most efficient motor and with the full delivery of its ballistic energy. It was also established, that the ballistic and rocket motor efficiency of a lower energy rocket motor can be improved by starting the ignition of such motor with fast burning dual-fuel rocket propellant (MODKNERK).

A Study on turbulence-combustion interaction and Sub-grid Scale model in the simulation of Methane pool fire using LES

In this paper, the effect of the combustion and turbulence sub-grid scale (SGS) model on the simulation of pool fire turbulence field has been studied in open source CFD software, OpenFOAM. Two combustion models of Eddy Dissipation Model (EDM) and infinite fast chemistry, with the one-equation and Smagorinsky SGS model, is evaluated for a large-scale pool fire. In general, fast kinetic-based combustion models predict excessive heat release rate. The mean squared of the velocity fluctuations is over-predicted. In this simulation, the turbulence models have no significant effect on the results. In fact, the effect of the combustion model is dominant. The EDM combustion model is more compatible when used with the one-equation SGS model and improves the results compared to other cases. In addition, the infinite fast chemistry combustion model is not a suitable model for fire simulation.

Performance of Ultra Shallow Floor Beams (USFB) exposed to standard and natural fires

This paper investigates computationally the fire performance of a plug steel-concrete composite flooring system, the partially encased ultra-shallow floor beams (USFB). The investigation of the behaviour of USFBs exposed to standard and natural fires is crucial in determining their fire resistance and evaluating their overall performance in contemporary construction. Although the product providers usually indicate the fire resistance of USFBs based on ΕΝ1994-1-2 procedures, the response to elevated temperature effects remains yet neither well documented nor clearly understood. This analysis involves two different beams of 5 m and 8 m span. Results show that the unprotected beams experience severe temperature gradients while exposed to standard fire, as the lower flange still remains unprotected in contrast to the upper steel parts of the cross-section which are encased in concrete. Their fire resistance rating is found approximately at 40 min. Moreover, different thermal gradients are developed when the USFBs are exposed to natural fires (slow and fast burning). When the lower flange is protected with intumescent coatings, the USFBs have shown increased fire resistance and they can survive a full duration of a natural fire under realistic utilization ratios. From the parametric analyses, the optimized thicknesses for the required intumescent coating were obtained to achieve 60, 90, and 120 min of fire resistance and for surviving of natural fires exposures.

The comparison between traditional spark ignition and micro flame ignition in gasoline high dilution combustion

Gasoline spark ignition (SI) – Controlled auto-ignition (CAI) hybrid combustion had previously been shown to expanding the operational range of high-efficiency low-temperature combustion and reducing fuel consumption. However, the spark ignition became ineffective when the mixture became highly diluted and the large cyclic variation and even misfire would occur. To achieve high-efficiency combustion in extended engine operational range and overcome the limitation of SI-CAI hybrid combustion, Micro Flame Ignition (MFI) was proposed and researched as a mean to providing multiple auto-ignition sites to initiate the combustion process of the diluted mixture. In this research, both engine experiments and Computational Fluid Dynamics (CFD) simulations were carried out to study the MFI combustion and SI-CAI hybrid combustion in a single-cylinder optical engine. Compared to the SI-CAI hybrid combustion, the flame propagation in MFI hybrid combustion was initiated by a large number of reaction fronts produced by the DME auto-ignition at multiple sites. MFI was found to deliver substantially more heat and ignition energy to the premixed mixture than the single spark ignition, enabling much faster initial heat release. However, the flame front expansion speed of MFI hybrid combustion dropped significantly to a similar value to that of the SI-CAI case because of the slower flame speed of diluted gasoline mixture. The MFI combustion exhibited three phases of autoignition stage, flame propagation stage and fast heat release stage. It is characterized by a higher peak heat release rate and shorter duration of the main combustion than those of the SI-CAI combustion. Besides, the use of spark ignition in the MFI operation promoted the autoignition of DME, leading to a shorter combustion duration and faster combustion than the MFI combustion without spark ignition. As a result, the spark assisted MFI strategy could be used to control the combustion phasing and optimize the MFI combustion process.

Experimental Study on Combustion and Performance of a Stationary CIDI Engine Fueled with 1-Heptanol-Diesel Mixtures

1-Heptanol is a renewable higher alcohol for compression ignition direct injection (CIDI) engines because of its distinctive physicochemical properties. The developed renewable production approaches of 1-heptanol promote its application in CIDI engines. The present study investigates the combustion of 1-heptanol/diesel blends with up to 50vol% 1-heptanol substitution ratio on CIDI engine. The substitution ratios of 1-heptanol/diesel are 10/90, 20/80, 30/70, 40/60, and 50/50 (v/v%), denoted as Hep10, Hep20, Hep30, Hep40, and Hep50. This work utilized a one-cylinder natural aspiration air cooling CIDI engine research facility. The steady-state test was performed at various loads ranged between 10% to 100% and engine speeds of 900 and 1500 rpm. The findings reveal that under the same conditions of the TGA experiment, the 1-heptanol/diesel mixture evaporates faster than diesel. 1-Heptanol/diesel mixtures showed longer ignition delay and tend to burn under premixed combustion mode than diesel. Also, Hep10-50 blends released more heat under fast burn mode compared to regular diesel. Hep10-50 mixtures showed higher cyclic variation (COVimep), higher BSFC, lower BTE, lower combustion efficiency, with no significant variations in cylinder pressure, THR, and IMEP compared to regular diesel. Soot and NOx emissions were demoted by 70% and 25% for Hep50 at 100% compared to diesel.

VOLUMES OF WORTH—DELIMITING THE SAMPLE SIZE FOR RADIOCARBON DATING OF PARCHMENT

ABSTRACTMedieval manuscripts are invaluable archives of the written history of our past. Manuscripts can be dated and localized paleographically, but this method has its limitations. The Fragmenta membranea manuscript collection at the National Library of Finland has proved difficult to date using paleographic methods. Radiocarbon dating has been applied to manuscripts of parchment before, but a systematic protocol for radiocarbon dating of parchment has not been established with a minimally destructive sampling strategy. In this work, we have established a radiocarbon dating procedure for parchments combining a clean-room based chemical pretreatment process, elemental analyzer combustion, automatic graphitization and accelerator mass spectrometry (AMS) measurements to reduce the AMS target size from a typical 1 mg of carbon. Prolonged acid treatment resulted in improved dating accuracy, since this is consistent with the manufacturing process of medieval parchment involving a lime bath. Two different combustion processes were compared. The traditional closed tube combustion (CTC) method provided a well-established though labor-intensive way to produce 1 mg AMS targets. The Elemental Analyzer-based process (EA-HASE, Elemental Analyzer Helsinki Adaptive Sample prEparation line), is designed for fast combustion and smaller sample sizes. The EA-HASE process was capable of reproducing the simulated radiocarbon ages of known-age samples with AMS graphite target sizes of 0.3 mg of carbon, corresponding to a 3 mm2 area of a typical medieval parchment. The full potential of the process to go down to as little as 50 μg will be further explored in the future in parallel to studies of sample-specific contamination issues.

One-pot microwave-assisted combustion synthesis of Ni-Al2O3 nanocatalysts for hydrogen production via dry reforming of methane

Ni-based catalysts supported on Al2O3 were obtained via a simple, low cost and fast one-pot microwave-assisted combustion synthesis. The effect of fuel content (urea) was investigate. It was observed that the fuel ratio greatly influences the catalysts properties and performance. The results showed that the catalyst synthesized with low fuel content (Ni-LU) presented high specific surface area (265 m2/g), high degree of reduction and smaller nanometric Ni particles (~15 nm). In addition, the catalytic tests carried out at 700 °C for 20 h (GHSV = 72 Lh−1g−1) revealed high activity with low coke deposition. Further investigations were conducted on Ni-LU catalyst in order to better understand its catalytic properties. In-situ X-ray diffraction analysis (using synchrotron radiation) was used to evaluate the Ni particle size during the DRM, and indicated the sintering of Ni particles during the first hour of catalytic reaction. Furthermore, small amount of carbon nanotubes (CNT) with Ni particles encapsulated were observed by TEM analysis.

Modelling and Fabrication of Engine Valve To Improve Performance of An I.C Engine

Modelling and fabrication of engine valves are made to increase the turbulence process by swirl. By proving swirl process to increase fast combustion phenomenon and enhance the efficiency of an engine. Engine should work at minimum speeds in order to have decrease the mechanical losses and good combustion enabling improves the combustion efficiency and mechanical efficiency (1). For this process be used to improves brake thermal efficiency and increase the usage of air-fuel mixture in combustion process which less impact pollution release to environment. The main importance of this work is to evaluate the performance of an Engine and to improve it by changing the valve design. Manufacturing of intake valves made to do an experimental work. this being done after modelling of valve and fabrication and then experimental work on test engine to compare two valves. Even if we adapt the this concept and also additional concentration required on inlet manifold.

Model Based Control Method for Diesel Engine Combustion

With the increase of information processing speed, more and more engine optimization work can be processed automatically. The quick-response closed-loop control method is becoming an urgent demand for the combustion control of modern internal combustion engines. In this paper, artificial neural network (ANN) and polynomial functions are used to predict the emission and engine performance based on seven parameters extracted from the in-cylinder pressure trace information of over 3000 cases. Based on the prediction model, the optimal combustion parameters are found with two different intelligent algorithms, including genetical algorithm and fish swarm algorithm. The results show that combination of quadratic function with genetical algorithm is able to obtain the appropriate combustion control parameters. Both engine emissions and thermal efficiency can be virtually predicted in a much faster way, such that enables a promising way to achieve fast and reliable closed-loop combustion control.

Formation of stabilized oblique detonation waves in a combustor

Initiation and stabilization of oblique detonation waves (ODWs) are important to the successful application of oblique detonation engines (ODEs), which, however, have been rarely studied under realistic combustor conditions. In this study, the flow structures, stabilization characteristics and potential thrust performance (under different combustor's geometries with different ODW reflection locations) in a typical hydrogen-fueled ODE combustor are numerically studied by solving the two-dimensional multi-species Reynolds-averaged conservation equations with a detailed hydrogen combustion mechanism. Results suggest that all the detonation waves/shock waves can be stabilized in the space-confined combustor, and the boundary layer separation induced by the ODW-boundary layer interaction is found crucial to determining the types of combustion mode in the combustor. Except for the expected ODW-induced combustion, fast combustion induced by a stabilized overdriven normal detonation wave (NDW) may exist in the combustor simultaneously (even up to a large extent, >73.7%). It is demonstrated that the stabilization of the overdriven NDW in the combustor can be attributed to the formation of an effective aerodynamic convergent-divergent nozzle that quickly accelerates the subsonic flow behind the NDW to supersonic, preventing downstream disturbances from propagating upstream. Benefiting from the chemical equilibrium shift caused by the expansion effect of the flow, more heat is released to compensate for the compression loss and the simulated thrust performance is shown not deteriorate significantly even with a large percentage of NDW-induced combustion existing in the ODE combustor. This work would be beneficial to the future developments of the ODEs.

Overall focus on research, including – Fusion of measurement and numerical analysis using weak flame phenomenon in micro combustion system

To achieve highly efficient internal combustion engines, it is essential that the fuel and air mixtures in cylinder burn rapidly without making undesired 'knocking' phenomena. Fuel reactions should be fast enough for attaining sufficiently fast exothermic combustion for power output but simultaneously, it should be durable to the undesired knocking, he notes. It is essential to clarify both ignition-related fuel reactivity and combustion processes that are governed by flame dynamics under intense turbulence. Obtained knowledge should be used for designing combustion phenomena. Dr Karou Maruta from the Institute of Fluid Science at Tohoku University is an expert in flame dynamics. Maruta and his team have been conducting a wide range of practical and theoretical experiments of weak flames in MFR ultimately for practical engine applications. They are looking to address the modelling capabilities of complex chemical reactions. In order to achieve this, the team is attempting to develop high fidelity chemical reaction kinetics, as well as intelligent computational methods.

Progress in multi-wave structure and stability of oblique detonations

Oblique detonation is an important direction in gaseous detonation physics and has great potential in the application of new-concept aeronautic and astronautic propulsion. As the fast combustion induced by shock, the oblique detonation wave could be simplified into a discontinuity with energy input. However, in oblique detonation flow, there concern several complicated fluid phenomena, such as shock wave and turbulence, which are coupled with the heat release and result in complicated flow and combustion mechanisms. A theoretical investigation is hard to be performed due to the characteristics of multi-scale and nonlinearity. Meanwhile, experimental investigation encounters the difficulties from measuring the flow fields of high temperature, high pressure, and high velocity. In the last two decades, the main progress of oblique detonation is achieved by numerical investigation through comprehensive simulation and analysis. First of all, the multi-wave structure of the initiation region and surface stability are introduced in the ideal inflow conditions. Then, derived from the application in engines, the effects of inflow inhomogeneity and interaction with expansion waves are studied and analyzed. Finally, some suggestions on future work are proposed and discussed.

Preparation of charcoal briquette from palm kernel shells: case study in Ghana

In Ghana, the potential of palm kernel shells as renewable energy in charcoal production has not been exploited adequately. Using a low-cost instrument (kiln and compressor box) built from local resources, we produced charcoal briquette from palm kernel (Elaeis guineensis) shells. Further, we measured and compared its efficiency using starch as a binder to traditional charcoal and commonly used fuelwood (Acacia) in Cape Coast. Following the American Standards for Testing and Materials (ASTM), the proximate analysis was conducted for all fuels with results indicating that palm kernel shell (PKS) briquette produced had a moisture content of 1.08 %, as compared to 9.25 % in charcoal and 16.00 % in fuelwood. The volatile matter, ash content and fixed carbon recorded were 71.80 %, 0.06 %, and 27.07 % in PKS briquette, 86.00 %, 0.78 %, and 3.97 % in charcoal and 80.50 %, 2.04 %, 1.46 % in fuelwood respectively. The calorific values for charred PKS increased after binding to form the PKS briquette with the highest value among the other fuels. The calorific value for the other fuels were 17.5 MJ/kg for charcoal, 18.72 MJ/kg for charred PKS, and 18.72 MJ/kg for PKS briquette. We also conducted an ignition test, combustion test, fuel burning rate (FBR), and specific fuel consumption (SFC) on PKS briquette and charcoal to determine their suitability as cooking fuels. Charcoal readily ignited as compared to PKS briquette with respective fuel mass of 5.08 g and 25.5 g. The resultant briquette possesses desirable combustion characteristics such as no smoke emissions and ash formation. The FBR and SFC in PKS briquette recorded the highest in comparison with charcoal. The values recorded were 2.84 g/min and 20.05 g/ml respectively while that of charcoal was 0.42 g/min and 3.48 g/ml respectively. PKS briquette produced from this study showed high calorific value, low moisture content, and a fast burning rate amongst other excellent properties. These properties are potential indicators that the proper utilization and production of PKS briquette as renewable energy in Ghana would contribute to solving the existing energy crisis. Additionally, reduce climate change impacts, via the reduction in the over-dependence on fuelwood and charcoal for domestic and commercial heating.

Ethylene glycol combustion strategy towards 3D mesoporous ZnCo2O4 as anodes for Li-ion batteries

A facile and fast ethylene glycol combustion strategy was developed to the synthesis of three-dimension (3D) mesoporous ZnCo2O4 architectures. It was found that the volume of colloidal silica employed in the combustion system exerts a profound impact on the specific surface area (SSA) and pore volume of 3D porous ZnCo2O4. The SSA and pore volume of 3D mesoporous ZnCo2O4–400 could reach up to 130 m2 g−1 and 0.641 cm3 g−1 when 400 μL of colloidal silica was used in the combustion system. When used as the LIB's anodes, the 3D mesoporous ZnCo2O4–400 could show high reversible capacity and superior cycling performance. The excellent performance is attributed to the high SSA and abundant mesoporous structures in the 3D mesoporous ZnCo2O4–400 architectures. The present work not only offers a novel synthetic route towards 3D mesoporous ZnCo2O4 but also demonstrates the vast prospect of 3D mesoporous ZnCo2O4 as the anode material for Li-ion batteries (LIBs).

Investigation of combustion modes and pressure of reflective shuttling detonation combustor

Detonation combustors are considered promising alternatives to conventional combustors because they offer high thermal efficiency and fast combustion. However, especially for the rotating detonation combustor, the theoretical propulsive performance has not been confirmed in experimental studies because the highly unsteady flow field hinders the measurements process. To understand the involved phenomena in more detail, a reflective shuttling detonation combustor (RSDC) with a rectangular combustion chamber was developed. The interior of the chamber can easily be visualized owing to its two-dimensional quality. Utilizing the RSDC, several combustion tests with gaseous ethylene and oxygen were conducted for different values of mass flow rates and equivalence ratios. Combustion modes from the tests were classified into four types based on the fast Fourier transform (FFT) analysis of the luminous intensity of the CH* self-luminescence images captured by a high-speed camera and a band pass filter. Simultaneously, the theoretical total pressure of a conventional isobaric combustor was compared to the static pressure measured at the bottom of the RSDC chamber. For the detonation modes, the ratio between experimentally measured static pressure and the theoretical pressure varied depending on the location in the chamber owing to the distribution of the time-averaged static pressure. Furthermore, the pressure ratio of the detonation modes was up to 18% lower than that of the deflagration mode potentially owing to the flow velocity induced by the detonation waves.

Numerical Investigation of a Free-Piston Hydrogen-Gasoline Engine Linear Generator

The free-piston engine linear generator (FPELG) is being investigated by many researchers because of its high thermal efficiency and its variable compression ratio. However, all researchers focused on the FPELG characteristics with mono-fuel. Therefore, in this paper, the performance of the FPELG that has adopted gasoline with hydrogen as fuel is investigated. The method of coupling the zero-dimensional dynamics model with the multi-dimensional CFD (Computational Fluid Dynamics) combustion model was applied during the simulation process. According to the results, the piston TDC (Top Dead Center), the piston peak piston velocity, and the system operation frequency show a negative correlation with the increase of hydrogen fractions. However, the peak in-cylinder pressure was increased with the hydrogen volume fraction increase, due to the fast flame speed and short combustion duration characteristics of hydrogen. Meanwhile, the indicated efficiency of the free-piston engine was increased from 32.3% to 35.3% with the hydrogen volume fraction change from 0% to 4.5%, when the free-piston engine operates at stoichiometric conditions with fixed ignition timing. In addition, with the ignition timing advance increase, the piston TDC was decreased. The peak piston velocity and the peak in-cylinder pressure were in negative correlation with the ignition timing advance. While the engine indicated that the efficiency was increased with the equivalent degree of ignition timing from 20° to 16°. Therefore, the ignition timing of the FPELG under the spark-ignition combustion mode is supposed to be an effective and practical control variable.

Porous network ZrO2/ZnFe2O4 nanocomposite with heterojunction towards industrial water purification under sunlight: Enhanced charge separation and elucidation of photo-mechanism

This work majorly aims to synthesize and also investigate the structural, optical, magnetic and optical features of ZrO2/ZnFe2O4 nanocomposite. Here, different ratios of novel hetero-junction ZrO2/ZnFe2O4 were synthesized by simple and fast solution combustion route. The X-ray diffraction results showed the formation of ZrO2 and ZnFe2O4 nanoparticles and ZrO2/ZnFe2O4 nanocomposites without any impurity. The formation of hetero-junction effectively inhibits the photo-generated charge carrier recombination. The degradation of Indigo Carmine dye by ZrO2/ZnFe2O4 photocatalyst was achieved through synergistic effects with 98% degradation and removal of 77% COD from the industrial dye waste water under Sunlight irradiation. Mixing of ferrites with zirconia greatly improves the photocatalytic activity that has been clearly proposed with the help of mechanism. ZZFO 12 NC exhibits better photocatalytic activity due to the combined facets of photo and Fenton activity. The exposure and enhancement of fingerprints in various surfaces are achieved by a modest, extremely sensitive and eco-friendly method. ZZFO12 NC offer great potential as an active photocatalyst for degradation of 54% of organic pollutant present in industrial waste water under natural Sunlight.

Analysis of the combustion process in a lean-burning turbulent jet ignition engine fueled with methane

Recent needs of reducing pollutant emissions of internal combustion engines have pushed the development of non-conventional ignition systems. One of the most promising techniques appears to be the so-called Turbulent Jet Ignition (TJI) system, in which a jet of high-energy reactive gases is generated by means of a pilot combustion in a pre-chamber and used to initiate the main combustion event in the cylinder. Considering the complex nature of some phenomena typical of TJI systems, 3D CFD studies are essential to provide a detailed analysis for an efficient design. In this study, numerical simulations of an active pre-chamber TJI system applied to a lean operating methane engine were performed to provide a thorough analysis of the combustion process that characterizes such a technology. The numerical model was validated against experimental measurements carried out on an optically accessible single cylinder spark-ignition engine equipped with the pre-chamber prototype. The numerical simulations provided an insight view of both physical and chemical phenomena occurring inside the pre-chamber otherwise difficult to achieve by experiments alone. The evolution of some species of interest was analyzed in order to study the main charge ignition process, as well as the overall combustion progress. The results show that the main charge ignition is made possible by the large amount of energy and active radicals released from the pre-chamber and this ensures an overall stable and faster combustion in lean conditions. The performance improvements of the TJI system with respect to a traditional spark-ignition engine were evaluated in terms of efficiency and pollutant emission levels.

Batch-scale synthesis of porous zinc manganese oxide with large specific surface area for Li-ion battery anodes

The spinel bimetal oxides with high specific surface area (SSA) are favorable to promote the energy storage performance of Li-ion batteries (LIBs). A facile and fast colloidal solution combustion strategy is explored to the batch-scale synthesis of porous zinc manganese oxide (ZnMn2O4) with tunable SSA. It is revealed that the volume of colloidal silica solution has a great influence on the SSA of porous ZnMn2O4. The porous ZnMn2O4–300 owns a maximum SSA of 186.4 m2 g−1, and a narrow pore size centered at 4–6 nm. Profiting from the high SSA and abundant mesopores, ZnMn2O4–300 electrode demonstrates superior Li storage performance when employed as LIB's anodes, delivering a desirable discharge capacity of 1784.3 mAh g−1 at the 1st discharge process, and 980.4 mAh g−1 of discharge capacity is remained at 500 mA g−1 after 165 cycles. Therefore, porous ZnMn2O4–300 has a broad developing prospect for LIB's anodes.

Efficiency and raw emission benefits from hydrogen addition to methane in a Prechamber–Equipped engine

Providing high ignition energies to low reactivity (hard-to-ignite) fuels in premixed combustion modes is a challenging task. This is especially true if diluted combustion and high compression ratios are applied which are desirable for achieving high efficiency levels. One promising technology is to decouple the ignition process from the conditions in the main chamber using a prechamber, which is able to ignite the charge in the engine's main combustion chamber using turbulent jets. In this study, experimental results of a prechamber-equipped four-cylinder engine with 2 L displacement are discussed. The engine is designed to provide high efficiency using natural gas as a fuel. The prechamber is able to be fueled externally (called active prechamber mode), e.g. the air–fuel equivalence ratio λ can be decoupled from the λ in the main combustion chamber. Besides of pure methane operation, the engine is operated with the addition of 22.5 mol% (3.5 mass%, 8.0 energy%) hydrogen to methane. The results show that it is beneficial to use auxiliary fueling of the prechamber in pure methane operation mode in order to achieve highest possible efficiency at low NOx levels at λ of around 1.7. When adding hydrogen, λ of around 1.7 still provides highest efficiency but auxiliary fueling of the prechamber is not necessary any more to enable fast and robust combustion. Compared to the active prechamber operation with methane, the 3.5 mass% (8.0 energy%) addition of hydrogen is able to reduce the engine's fuel energy demand by 1.3–3.3% in relevant engine operating points, which leads to tailpipe CO2 reductions of 9.2–11%. Additionally, hydrogen addition is able to disproportionately lower the engine's unburned hydrocarbon (HC) emissions: The addition of 3.5 mass% hydrogen lowers HC mass emissions by impressive 30–40%. Simultaneously, at the lean conditions considered, CO and NOx emissions are lowered by around 20%.