Biogas is one of the alternative solutions that could reduce the usage of fossil fuels and production of greenhouse gas emissions, as biogas is considered as an alternative fuel with a short carbon cycle. During biogas production, organic matter is decomposed during an anaerobic digestion process. Biogas mainly consists of methane and carbon dioxide, of which the ratio varies depending on the raw material and parameters of the production process. Therefore, engine parameters should be adjusted in relationship with biogas composition. In this research, a spark ignition engine was tested for mixtures of biogas with 0 vol%, 20 vol%, 40 vol% and 50 vol% of CO₂. In all experiments, two cases of spark timing (ST) were used; the first one is a constant spark timing (26 crank angle degrees (CAD) before top dead center (BTDC)) and the second one is an advanced spark timing (optimal for biogas mixture). Results show that increasing the CO₂ concentration and using constant spark timing increases the mass burned fraction combustion duration by 90%, reduces the in-cylinder pressure and leads to a reduction in the brake thermal efficiency and nitrogen oxides emissions at all measurement points. However, the choice of optimal spark timing increases the brake thermal efficiency as well as hydrocarbon and CO₂ emission.

Biogas has increasingly been used as an alternative to fossil fuels in the world due to a number of factors, including the availability of raw materials, extensive resources, relatively cheap production and sufficient energy efficiency in internal combustion engines. Tightening environmental and renewable energy requirements create excellent prospects for biogas (BG) as a fuel. A study was conducted on a 1.6-L spark ignition (SI) engine (HR16DE), testing simulated biogas with different methane and carbon dioxide contents (100CH₄, 80CH₄_20CO₂, 60CH₄_40CO₂, and 50CH₄_50CO₂) as fuel. The rate of heat release (ROHR) was calculated for each fuel. Vibration acceleration time, sound pressure and spectrum characteristics were also analyzed. The results of the study revealed which vibration of the engine correlates with combustion intensity, which is directly related to the main measure of engine energy efficiency—break thermal efficiency (BTE). Increasing vibrations have a negative correlation with carbon monoxide (CO) and hydrocarbon (HC) emissions, but a positive correlation with nitrogen oxide (NO_x) emissions. Sound pressure also relates to the combustion process, but, in contrast to vibration, had a negative correlation with BTE and NO_x, and a positive correlation with emissions of incomplete combustion products (CO, HC).

This study investigates the impact of hydrogen supplementation on the performance, efficiency, and emissions of a spark-ignition internal combustion engine, with a specific focus on knock phenomena. A Nissan HR16DE engine was modified to operate in a dual-fuel mode using gasoline (E95) and high-purity hydrogen. Hydrogen was injected via secondary manifold injectors and managed through a reprogrammable MoTeC ECU, allowing precise control of ignition timing and fuel delivery. Experiments were conducted across various engine speeds and loads, with hydrogen mass fractions ranging from 0% to 30%. Results showed that increasing hydrogen content enhanced combustion intensity, thermal efficiency, and stability. Brake specific fuel consumption decreased by up to 43.4%, while brake thermal efficiency improved by 2–3%. CO, HC, and CO₂ emissions were significantly reduced. However, NO_x emissions increased with higher hydrogen concentrations due to elevated combustion temperatures. Knock tendency was effectively mitigated by retarding ignition timing, ensuring peak in-cylinder pressure occurred at 14–15° CAD aTDC. These findings demonstrate the potential of hydrogen supplementation to reduce fossil fuel use and greenhouse gas emissions in spark ignition engines, while highlighting the importance of precise combustion control to address challenges such as knock and NO_x formation.

Technologies used in the transport sector have a substantial impact on air pollution and global warming. Due to the immense impact of air pollution on Earth, it is crucial to investigate novel ways to reduce emissions. One way to reduce pollution from ICE is to use alternative fuels. However, blends of alternative fuels in different proportions are known to improve some emissions’ parameters, while others remain unchanged or even worsen. It is therefore necessary to find ways of reducing all the main pollutants. For SI engines, mixtures of hydrogen and natural gas can be used as alternative fuels. The use of such fuel mixtures makes it possible to reduce CO, HC, and CO₂ emissions from the engine, but the unique properties of hydrogen tend to increase NO_x emissions. One way to address this challenge is to use port water injection (PWI). This paper describes studies carried out under laboratory conditions on an SI engine fuelled with CNG and CNG + H₂ mixtures (H₂ = 5, 10, 15% by volume) and injected with 60 and 120 mL/min of water into the engine. The tests showed that the additional water injection reduced CO and NO_x emissions by about 20% and 4–5 times, respectively. But, the results also show that water injection at the rate of 120 mL/min increases fuel consumption by between 2.5% and 7% in all cases.

The utilization of “green” hydrogen in transportation areas gives rise to production- and supply infrastructure-related challenges; therefore, its wider application in automotive transport would lead to higher demand with cost reduction and a faster expansion of the hydrogen refuelling network. This study presents energy and environmental performance indicators analyses of a Nissan Qashqai J10 engine during the Worldwide Harmonised Light Vehicles Test Cycle (WLTC), replacing conventional fossil gasoline with dual-fuel (D-F) gasoline and hydrogen. Numerical modelling was conducted using AVL Cruise™ (Version R2022.2) software, utilizing the torque, fuel consumption, and environmental performance data of the HR16DE engine obtained through experimental testing across a wide range of loads and speeds on an engine test bench. The experimental investigation was carried out in two stages: using pure gasoline (G100); injecting a hydrogen additive into the intake air, constituting 5% of the gasoline mass (G95H5). Following similar stages, numerical modelling was conducted using the vehicle’s technical specifications to calculate engine load and speed throughout the WLTC range. Instant fuel consumption and pollutant emissions (CO, CH, NO_x) were determined for various driving modes using experimental data maps. CO₂ emissions were calculated considering fuel composition and consumption. By integrating the instant values, the total and specific fuel consumption and emissions were calculated. As a result, this study identified the effect of a 5% hydrogen additive in improving engine energy efficiency, reducing incomplete combustion products and lowering greenhouse gas (CO₂) emissions under various driving modes. Finally, the results were compared with the requirements of EU standards.

This study investigates the effect of partial hydrogen substitution of E10 fuel on the performance, fuel consumption, and emissions of a spark-ignition engine. Tests were carried out using a Toyota Avensis equipped with a 1ZZ-FE engine on a MAHA LPS 3000 chassis dynamometer. The engine was operated at 3000 rpm, at a vehicle speed of 50 km/h, and with an excess air ratio close to λ = 1. Four fuel cases were compared: E10H0, E10H05, E10H09, and E10H11. Results indicate that hydrogen addition reduced gasoline consumption and improved brake thermal efficiency. Specifically, at the maximum load point, gasoline consumption decreased from 8.2 kg/h to 6.0 kg/h, while the maximum brake thermal efficiency increased from 0.311 for E10H0 to 0.328 for E10H05. Hydrogen addition also reduced CO, HC, and CO₂ emissions. At 32 kW, CO decreased from 0.116% to 0.056%; HC, from 6.3 ppm to 3.6 ppm; and CO₂, from 15.0% to 11.6%. NO_x increased from 17 ppm to 24 ppm. The results show that hydrogen addition can reduce gasoline consumption and carbon-based emissions, but the hydrogen fraction must be optimized to limit NO_x formation.