SI engine assessment using biogas,natural gas and syngas with different content of hydrogen for application in Brazilian rice industries: Efficiency and pollutant emissions

After Asia, Brazil is the world's largest rice producer. During the processing of the grain, large amounts of husk are generated, corresponding to 22% of its weight. On the other hand, in the process of parboiling, in turn, the final result is considerable volumes of effluents rich in organic matter, generating large amounts of methane gas through anaerobic treatment. Therefore, the SI engine can operate with mixtures of biogas and syngas, generating electricity and heat in the Brazilian rice industries. In addition, it reduces the emissions of polluting gases that are generated with a direct burning of the husks instead of their gasification, as well as the use of methane gas. Accordingly, in this work, it was used the spark-ignition engine operating with one of the typical biogas and syngas compositions generated in the rice industries, named Bio65 (containing 65% of CH₄ by vol.), syngas1 (containing 18,3% of H₂ by vol.), and syngas2 (containing 13,5% of H₂ by vol.), respectively. Additionally, the tests with natural gas as a reference fuel have been performed. It was evaluated the emissions of polluting gases such as CO, NO_x and HC, as well as the thermal and electrical efficiency of all tested fuels. An important result that could be observed was that for both natural gas and biogas fuel, the increase in excess ratio (λ) value from 1 to 1.5 led to lower NO_x and CO emissions, even if with increased HC emissions. On the other hand, the Indicated Specific Energy Consumption increased to all the fuels tested in lean conditions in almost all ignition advances angles. The research tried to show that biogas and syngas can be used in parboiling rice industries, taking the advantage of the generated gases for energy self-sufficiency as well as reducing emissions.     

Investigation of combustion characteristics and emissions in a spark-ignition engine fuelled with natural gas–hydrogen blends

In this study, an experimental study on the performance and exhaust emissions of a spark-ignition engine fuelled with methane–hydrogen mixtures (100% CH₄, 10% H₂ + 90% CH₄, 20% H₂ + 80% CH₄, and 30% H₂ + 70% CH₄) were performed at different engine speeds and different excessive air ratios. This present work was carried out on a Ford engine. This is a four-stroke cycle four-cylinder spark-ignition engine with a bore of 80.6 mm, a stroke of 88 mm and a compression ratio of 10:1. Experiments were performed at 1500, 2000, 2500 and 3000 rpm and at wide open throttle (WOT). CO, CO₂ and HC emission values and cylinder pressure were measured. The results showed that while the speed and excessive air ratio increase, CO emission values decrease. The reduction of HC and CO emissions could be obtained by adding hydrogen into the natural gas when operating on the lean mixture condition. Increasing the excessive air ratio also decreases the maximum peak cylinder pressure.     

Effect of hydrogen addition using on-board alkaline electrolyser on SI engine emissions and combustion

In this study, an electrolyser was used to supply hydrogen to the SI engine. Firstly, the appropriate operation point for the electrolyser was determined by adjusting the amount of KOH in the electrolyte to 5%, 10%, 20% and 30% by mass, and applying 12 V, 16 V, 20 V, 24 V and 28 V voltages. Tests were first carried out with the gasoline without the use of an electrolyser, followed by operating the electrolyser at the appropriate point and sending obtained H₂ and O₂ to the engine in addition to the gasoline. The SI engine was operated between 2500 rpm and 3500 rpm engine speeds with and without hydrogen addition. Cylinder pressure, the amount of gasoline, H₂ and O₂ consumed by the engine and the emission data were collected from the test system at the aforementioned engine speeds. Furthermore, indicated engine torque, indicated specific energy consumption, specific emissions and HRR values were calculated. According to the results obtained, improvement in ISEC values was observed, and CO and THC values were improved by up to 21.3% and 86.1% respectively. Even though the dramatic increase in NO_x emissions cannot be averted, they can be controlled by equipment such as EGR three-way catalytic converter.     

Synergetic influence of hydrogen peroxide emulsification and MWCNT nanoparticles to reduce engine exhaust emissions using B20 biodiesel blend

In this study, the combined synergetic influence of H₂O₂ emulsification with the addition of multi-walled carbon nanotubes (MWCNT) to B20 biodiesel blend is ascertained on the exhaust emissions and performance of a compression ignition engine. Methyl ester obtained from waste cooking oil is used to prepare B20 blend. Variation in the concentrations of H₂O₂ (0.5%, 1%, 1.5%) and MWCNT (0, 20, 40 ppm) was carried out at 50%–100% of the full load condition. Increasing the concentrations of H₂O₂ and MWCNT positively affect the emissions of CO, HC, and Smoke, wherein a maximum reduction of 52%, 30.2%, and 16.1%, respectively, was achieved. Similarly, the average increase in brake thermal efficiency and an average reduction in brake specific fuel consumption is seen to be 10.3% and 9.1%, respectively. An increasing trend for NOx was seen with the increase in the MWCNT concentration (average increase by 10.2%). However, H₂O₂ emulsification resulted in an average decrease of 21.5%, indicating that H₂O₂ had a more dominating effect due to hydroperoxyl radicals. Fitting models between the controlling factors and the response of emissions and performance parameters were developed using an artificial neural network (ANN) (R² > 0.99). From studying the interaction of H₂O₂ and MWCNT using ANN-derived response surface plots, it is seen that H₂O₂ emulsification dominated the effect of MWCNT nanoparticles for the responses of CO, HC, Smoke, NOx, and BTE.     

Characterization of flame front propagation during early and late combustion for methane-hydrogen fueling of an optically accessible SI engine

In recent years, hybrid and fully electric vehicles have received significant consideration since they represent an alternative sustainable transport to the conventional fossil-fuel powered vehicles. However, a worldwide implementation of this alternative propulsion can induce large and undesirable peak demands in distributed power systems. In this context, natural gas spark ignition engines are a promising form of technology to supply part of the energy demand. The main limitations related to low laminar flame propagation speed and poor lean-burn capabilities of natural gas can be overcome by using hydrogen as additional fuel. In this paper, a comparison was carried out between methane and different CH₄/H₂ mixtures. Specifically, low levels of hydrogen addition were used (5%, 10%, 20% volumetric basis) in stoichiometric and lean burn conditions. The measurements were carried out in an optically accessible single-cylinder port fuel injection spark ignition engine. Optical measurements were performed to analyze the combustion process with high spatial and temporal resolution. In particular, optical techniques based on 2D-digital imaging with two different combustion chamber views were used. Macroscopic (global) and microscopic (local) post-processing tools were implemented to provide a detailed analysis of the flame front propagation process. Moreover, an in-depth analysis was performed to study the flame penetration in the piston top-land crevice. Exhaust gas emissions were also characterized and linked with thermodynamic and optical data. In order to evaluate the combustion process in similar fluid-dynamic conditions, all measurements were performed under steady-state conditions at fixed engine speed, load and spark advance. All the results highlight fast combustion promotion due to the hydrogen addition. In addition, hydrogen reduces the preferential propagation of the flame in a certain direction and increases the flame front wrinkling. Flame propagation in the top-land crevice region was measured for methane and its blends with hydrogen, which represents an original contribution to the literature. An inverse trend was seen between flame penetration in the crevice and unburned hydrocarbon emissions. Lastly, tests in lean conditions demonstrate the potential to decrease nitrogen oxides emissions when methane and methane-hydrogen blends are used.     

Study of turbocharged diesel engine operation,pollutant emissions and combustion noise radiation during starting with bio-diesel or n-butanol diesel fuel blends

The control of transient emissions from turbocharged diesel engines is an important objective for automotive manufacturers, as stringent criteria for exhaust emissions must be met. Starting, in particular, is a process of significant importance owing to its major contribution to the overall emissions during a transient test cycle. On the other hand, bio-fuels are getting impetus today as renewable substitutes for conventional fuels, especially in the transport sector. In the present work, experimental tests were conducted at the authors’ laboratory on a bus/truck, turbocharged diesel engine in order to investigate the formation mechanisms of nitric oxide (NO), smoke, and combustion noise radiation during hot starting for various alternative fuel blends. To this aim, a fully instrumented test bed was set up, using ultra-fast response analyzers capable of capturing the instantaneous development of emissions as well as various other key engine and turbocharger parameters. The experimental test matrix included three different fuels, namely neat diesel fuel and two blends of diesel fuel with either bio-diesel (30% by vol.) or n-butanol (25% by vol.). With reference to the neat diesel fuel case during the starting event, the bio-diesel blend resulted in deterioration of both pollutant emissions as well as increased combustion instability, while the n-butanol (normal butanol) blend decreased significantly exhaust gas opacity but increased notably NO emission.     

Study of performance,combustion, and NOx emission behavior of an SI engine fuelled with ammonia/hydrogen blends at various compression ratio

In the present paper, an experimental investigation has been performed under variable CR and 1400&1800RPM speed at a fixed spark timing of 24ºCA BTDC under wide-open throttle conditions. The hydrogen blending is performed based on energy fractions from 5% to 21% of the total fuel energy. With increasing compression ratio (CR), the flame development gets faster, and the flame propagation speed improves, leading to a short combustion period. Similarly, increasing hydrogen fraction improves combustion, resulting in a rapid rise in pressure and temperature. Despite a 13.64% decrease in volumetric efficiency from 5% to 21% hydrogen fraction at 1400 and 1800 RPM, BP and BTE increased by 16.89% and 33%, respectively. The slow-burning properties of NH₃ extend the combustion period, resulting in a long-delayed burning period. As a result, the temperature of the low-hydrogen fraction of the exhaust gas is higher. As the hydrogen fraction and CR increase, this effect decreases, resulting in lower EGT. The hydrogen addition increases the peak temperature; therefore, NO_x increases continuously with increasing hydrogen despite reducing ammonia. Ammonia is a key element used to reduce NO_x from vehicles. A practical solution for controlling the NO_x due to the ammonia/hydrogen blend is selective catalytic reduction (SCR).     

Experimental study of combustion performances and emissions of a spark ignition cogeneration engine operating in lean conditions using different fuels

This work presents an experimental study describing a six-cylinder spark ignition engine running with a lean equivalence ratio, high compression ratio, ignition delay and used in a cogeneration system (heat and electricity production). Three types of fuels; natural gas, pure methane and methane/hydrogen blend (85% CH₄ and 15% H₂ by volume), were used for comparison purposes. Each fuel has been investigated at 1500 rpm and for various engine loads fixed by electrical power output conditions. CO, CO₂, HC, and NOx emissions values, and exhaust gas temperature were measured. The effect of fuel composition on engine characteristics has been studied. The results show, that the hydrogen addition increased HC emissions (around 18%), as well as performance, whilst it reduced NO_x (around 31%), exhaust gas temperature, CO and CO₂.     

Effect of the turbulence intensity on knocking tendency in a SI engine with high compression ratio using biogas and blends with natural gas,propane and hydrogen

This research presents the test results carried out in a diesel engine converted to spark ignition (SI) using gaseous fuels, applying a geometry change of the pistons combustion chamber (GCPCC) to increase the turbulence intensity during the combustion process; with similar compression ratio (CR) of the original diesel engine; the increase in turbulence intensity was planned to rise turbulent flame speed of biogas, to compensate its low laminar flame speed. The research present the test to evaluate the effect of increase turbulence intensity on knocking tendency; using fuel blends of biogas with natural gas, propane and hydrogen; for each fuel blend the maximum output power was measured just into the knocking threshold before and after GCPCC; spark timing (ST) was adjusted for optimum generating efficiency at the knocking threshold. Turbulence intensity with GCPCC was estimated using Fluent 13, with 3D Combustion Fluid Dynamics (CFD) numerical simulations; 12 combustion chamber geometries were simulated in motoring conditions; the selected geometry had the greatest simulated turbulent kinetic energy (TKE) and Reynolds number (Re) during combustion. The increased turbulence intensity was measured indirectly through the periods of combustion duration to mass fraction burn 0–5%, 0–50% and 0–90%; for almost all the fuel blends the increased turbulence intensity of the engine, increased the knocking tendency requiring to reduce the maximum output power to keep engine operation just into the knocking threshold. Biogas was the only fuel without power derating by the conditions of higher pressure and higher turbulence during combustion by GCPCC and improve its generating efficiency. Peak pressure, heat release rate, mean effective pressure and exhaust temperature were lower after GCPCC. Tests results indicated that knocking tendency was increased because of the higher turbulent flame speed; fuel blends with high laminar flame speed and low methane number (MN) had higher knocking tendency and lower output power.     

Application of artificial neural networks for the prediction of performance and exhaust emissions in SI engine using ethanol- gasoline blends

This study deals with artificial neural network (ANN) modeling of a spark ignition engine to predict the engine brake power, output torque and exhaust emissions (CO, CO₂, NO_x and HC) of the engine. To acquire data for training and testing of the proposed ANN, a four-cylinder, four-stroke test engine was fuelled with ethanol-gasoline blended fuels with various percentages of ethanol (0, 5, 10,15 and 20%), and operated at different engine speeds and loads. An ANN model based on standard back-propagation algorithm for the engine was developed using some of the experimental data for training. The performance of the ANN was validated by comparing the prediction dataset with the experimental results. Results showed that the ANN provided the best accuracy in modeling the emission indices with correlation coefficient equal to 0.98, 0.96, 0.90 and 0.71 for CO, CO₂, HC and NO_x, and 0.99 and 0.96 for torque and brake power respectively. Generally, the artificial neural network offers the advantage of being fast, accurate and reliable in the prediction or approximation affairs, especially when numerical and mathematical methods fail.     

Effects of split injection proportion and the second injection timings on the combustion and emissions of a dual fuel SI engine with split hydrogen direct injection

In this paper, a new kind of injection mode, split hydrogen direct injection, was presented for a dual fuel SI engine. Six different first injection proportions (IP1) and five different second injection timings were applied at the condition of excess air ratio of 1, first injection timing of 300°CA BTDC, low speed, low load conditions and the Minimum spark advance for Best Torque (MBT) on a dual fuel SI engine with hydrogen direct injection (HDI) plus port fuel injection (PFI). The result showed that, split hydrogen direct injection can achieve a higher brake thermal efficiency and lower emissions compared with single HDI. In comparison with single HDI, the split hydrogen direct injection can form a controlled stratified condition of hydrogen which could make the combustion more complete and faster. By adding an early spray to form a more homogeneous mixture, the split hydrogen direct injection not only can help to form a flame kernel to make the combustion stable, but also can speed up the combustion rate through the whole combustion process, which can improve the brake thermal efficiency. By split hydrogen direct injection, the torque reaches the highest when the first injection proportion is 33%, which improves by 1.13% on average than that of single HDI. With the delay of second injection timing, the torque increases first and then decreases. With the increase of first injection proportion, the best second injection timing is advanced. Furthermore, by forming a more homogeneous mixture, the split hydrogen direct injection can reduce the quenching distance to reduce the HC emission and reduce the maximum temperature to reduce the NO_X. The split hydrogen direct injection can reduce the HC emission by 35.8%, the NO_X emissions by 7.3% than that of single HDI.     

Effect on performance and emissions of a dual fuel diesel engine using hydrogen and producer gas as secondary fuels

Energy is an essential prerequisite for economical and social growth of any country. Skyrocketing of petroleum fuel cost s in present day has led to growing interest in alternative fuels like CNG, LPG, Producer gas, Biogas in order to provide suitable substitute to diesel for a compression ignition engine. This paper discusses some experimental investigations on dual fuel operation of a 4 cylinder (turbocharged and intercooled) 62.5 kW gen-set diesel engine with hydrogen, producer gas (PG) and mixture of producer gas and hydrogen as secondary fuels. Results on brake thermal efficiency and emissions, namely, un-burnt hydrocarbon (HC), carbon monoxide (CO), and NO_x are presented here. The paper also contains vital information relating to the performances of an engine at a wide range of load conditions with different gaseous fuel substitutions. When only hydrogen is used as secondary fuel, maximum increase in the brake thermal efficiency is 7% which is obtained with 20% of secondary fuel. When only producer gas is used as secondary fuel, maximum decrease in the brake thermal efficiency of 8% is obtained with 30% of secondary fuel. Compared to the neat diesel operation, proportion of un-burnt HC and CO increases, while, emission of NO_x reduces in all Cases. On the other hand, when 40% of mixture of producer gas and hydrogen is used (in the ratio (60:40) as secondary fuel, brake thermal efficiency reduces marginally by 3%. Further, shortcoming of low efficiency at lower load condition in a dual fuel operation is removed when a mixture of hydrogen and producer gas is used as the secondary fuel at higher than 13% load condition. Based on the performance studied, a mixture of producer gas and hydrogen in the proportion of 60:40 may be used as a supplementary fuel for diesel conservation.     

S.I. engine fuelled with gasoline,methane and methane/hydrogen blends: Heat release and loss analysis

Experiments were carried out to investigate the performance of different fuels used in a internal combustion engine: gasoline, methane and fuel blends containing methane with 5%, 10% and 15% hydrogen by volume, respectively. A two-litre naturally aspirated bi-fuel engine with port fuel injection was used. The engine was operated stoichiometrically. For each fuel the spark advance for best efficiency was determined. Experiments were conducted at 2000 rpm and 2 bar brake mean effective pressure. A heat release analysis and a loss analysis were performed for all fuels. The main findings are that increasing the hydrogen fraction of the methane hydrogen fuel blend decreases the overall burn duration. This decrease is predominantly achieved by a shortened duration of the fist stage of combustion (ignition to 5% mass fraction burned). The faster combustion comes along with an increase in fuel conversion efficiency. The different losses for gasoline and pure methane operation interact such that equal fuel conversion efficiencies result. However, care has to be taken when comparing fuel conversion efficiencies among the different fuels as the relative error in fuel conversion efficiency for the gaseous fuels is 0.2% at most, whereas it is about 1% for gasoline.     

Numerical study on effects of hydrogen direct injection on hydrogen mixture distribution,combustion and emissions of a gasoline/hydrogen SI engine under lean burn condition

A numerical study on effects of hydrogen direct injection on hydrogen mixture distribution, combustion and emissions was presented for a gasoline/hydrogen SI engine. Under lean burn conditions, five different direct hydrogen injection timings were applied at low speeds and low loads on SI engines with direct hydrogen injection (HDI) and gasoline port injection. The results were showed as following: firstly, with the increase of hydrogen direct injection timing, the hydrogen concentration near the sparking plug first increases and then decreases, reaching the highest when hydrogen direct injection timing is 120°CA BTDC: Secondly, hydrogen can speed up the combustion rate. The main factor affecting the combustion rate and efficiency is the hydrogen concentration near the sparking plug: Thirdly, in comparing with gasoline, the NO_X emissions with hydrogen addition increase by an average of 115%. For different hydrogen direct injection timings, the NO_X emissions of 120°CA BTDC is the highest, which is 29.9% higher than the 75°CA BTDC. The hydrogen addition make the NO_X emissions increase in two ways. On the one hand, the average temperature with hydrogen addition is higher. On the other hand, the temperature with hydrogen addition is not homogeneous, which makes the peak of temperature much higher. In a word, the main factor of NO_X emissions is the size of high temperature zone in the cylinder: Finally, because the combustion is more complete, in comparing with gasoline, hydrogen addition can reduce the CO and HC emissions by 32.2% and 80.4% respectively. Since a more homogeneous hydrogen mixture distribution can influence a lager zone in the cylinder and reduce the wall quenching distance, these emissions decrease with the increase of hydrogen direct injection timing. The CO and HC emissions of 135°CA BTDC decrease by 41.5% and 71.4%, respectively, compared to 75°CA BTDC.     

Experimental investigation of the combustion characteristics,emissions and performance of hydrogen port fuel injection in a diesel engine

Diesel engines are indispensable in daily life. However, the limited supply of petroleum fuels and the stringent regulations on such fuels are forcing researchers to study the use of hydrogen as a fuel. In this study, a diesel engine is operated using hydrogen–diesel dual fuel, where hydrogen is introduced into the intake manifold using an LPG-CNG injector and pilot diesel is injected using diesel injectors. The energy contents of the total fuel, 0%, 16%, 36% and 46% hydrogen (the 0% hydrogen energy fraction represents neat diesel fuel), were tested at 1300 rpm of constant engine speed and 5.1 kW of constant indicated power. According to test results, the indicated thermal efficiency of the engine decreases and the isfc increases with an increasing hydrogen energy fraction. Additionally, indicated specific CO, CO₂ and smoke emissions decrease with an increasing percentage of hydrogen fuel. However, indicated specific NO_x emissions do not change at the 16% hydrogen energy fraction, in other words, with an increase in the hydrogen amount (36% and 46% hydrogen energy fraction of total fuel), a dramatic increase (58.8% and 159.7%, respectively) is observed. Additionally, the peak in-cylinder pressure and the peak heat release rate values increase with the increasing hydrogen rate.     

Deactivation of Pt/VC proton exchange membrane fuel cell cathodes by SO2, H2S and COS

Sulfur contaminants in air pose a threat to the successful operation of proton exchange membrane fuel cells (PEMFCs) via poisoning of the Pt-based cathodes. The deactivation behavior of commercial Pt on Vulcan carbon (Pt/VC) membrane electrode assemblies (MEAs) is determined when exposed to 1 ppm (dry) of SO₂, H₂S, or COS in air for 3, 12, and 24 h while held at a constant potential of 0.6 V. All the three sulfur compounds cause the same deactivation behavior in the fuel cell cathodes, and the polarization curves of the poisoned MEAs have the same decrease in performance. Sulfur coverages after multiple exposure times (3, 12, and 24 h) are determined by cyclic voltammetry (CV). As the exposure time to sulfur contaminants increases from 12 to 24 h, the sulfur coverage of the platinum saturates at 0.45. The sulfur is removed from the cathodes and their activity is partially restored both by cyclic voltammetry, as shown by others, and by successive polarization curves. Complete recovery of fuel cell performance is not achieved with either technique, suggesting that sulfur species permanently affect the surface of the catalyst.     

Comparisons of the impact of reformer gas and hydrogen enrichment on flame stability and pollutant emissions for a kerosene/air swirled flame with an aeronautical fuel injector

Experimental studies were conducted on an actual aeronautical fuel injector, at conditions close as possible of the idle regime of the aircraft (P = 0.3 MPa and T = 500 K), to characterize the flame stability and pollutant emissions of two-phase kerosene/air flames. The objective was to investigate the effects of H₂ and reformer gases (RG containing H₂) enrichment of kerosene at constant power for the adaptation to an aircraft engine. Two different gas injection configurations have been tested (partially premixed, PP, and fully premixed, FP) to evaluate the consequences of the fuel injection mode on gas enrichment. We demonstrate the main interest and the benefits of RGs for aeronautical gas turbines. Through chemical mechanisms, they increase the flame stability and strongly reduce CO emissions without dramatically increasing NO_x emissions, in comparison with the injection of pure hydrogen. Their overall behavior is independent from the injection configuration.     

Effect of compression ratio, equivalence ratio and engine speed on the performance and emission characteristics of a spark ignition engine using hydrogen as a fuel

The present energy situation has stimulated active research interest in non-petroleum and non-polluting fuels, particularly for transportation, power generation, and agricultural sectors. Researchers have found that hydrogen presents the best and an unprecedented solution to the energy crises and pollution problems, due to its superior combustion qualities and availability. This paper discusses analytically and provides data on the effect of compression ratio, equivalence ratio and engine speed on the engine performance, emissions and pre-ignition limits of a spark ignition engine operating on hydrogen fuel.These data are important in order to understand the interaction between engine performance and emission parameters, which will help engine designers when designing for hydrogen.     

Effects of oxyhydrogen on the CI engine fueled with the biodiesel blends: A performance,combustion and emission characteristics study

The main purpose of this study is to analyse the effects of oxy hydrogen (HHO) along with the Moringa oleifera biodiesel blend on engine performance, combustion and emission characteristics. HHO gases were generated using the typical electrolysis process using the potassium hydroxide solution. The experiments were performed under various engine loads of 25%, 50%, 75%, and 100% in a constant speed engine. Biodiesel from the M. oleifera was prepared by the transesterification process. Further, the procured biodiesel blends mixed with neat diesel at the concentration of 20% (B20) and 40% (B40). In addition to above, the HHO gas flow rate to the engine chamber maintained at the flow rate of 0.5 L^-1. The use of the 20% and 40% blends with HHO reported less BTE compared to the neat diesel. However, B20 reported marginal rise in the BTE due to the addition of the HHO gas. On the other hand, addition of HHO gas to the blends significantly dropped the brake specific fuel consumption. With regard to the emissions, addition of the biodiesel blends reduced the concentration of the CO, HC, and CO₂. Nevertheless, no reduction reported in the formation of the NO. However, adding the HHO to the biodiesel reduced the average NOx by 6%, which is a substantial effect. Overall, HHO enriching biodiesel blends are the potential replacement for the existing fossil fuels for its superior fuel properties compared to the conventional diesel.     

Strategies to improve the performance of a spark ignition engine using fuel blends of biogas with natural gas,propane and hydrogen

This work presents the strategies applied to improve the performance of a spark ignition (SI) biogas engine. A diesel engine with a high compression ratio (CR) was converted to SI to be fueled with gaseous fuels. Biogas was used as the main fuel to increase knocking resistance of the blends. Biogas was blended with natural gas, propane, and hydrogen to improve fuel combustion properties. The spark timing (ST) was adjusted for optimum generating efficiencies close to the knocking threshold. The engine was operated on each blend at the maximum output power under stable combustion conditions. The maximum output power was measured at partial throttle limited by engine knocking threshold. The use of biogas in the engine resulted in a power derating of 6.25% compared with the original diesel engine (8 kW @ 1800 rpm). 50% biogas + 50% natural gas was the blend with the highest output power (8.66 kW @1800 rpm) and the highest generating efficiency (29.8%); this blend indeed got better results than the blends enriched with propane and hydrogen. Tests conditions were selected to achieve an average knocking peak pressure between 0.3 and 0.5 bar and COV of IMEP lower than 4% using 200 consecutive cycles as reference. With the blends of biogas, propane, and hydrogen, the output power obtained was just over 8 kW whereas the blends of biogas, natural gas, and hydrogen the output power were close to 8.6 kW. Moreover, a new approach to evaluate the maximum output power in gas engines is proposed, which does not depend on the engine % throttle but on the limit defined by the knocking threshold and cyclic variations.