Potential of alcohol fuels in active and passive pre-chamber applications in a passenger car spark-ignition engine

Both the shift from fossil to alternative fuels and the implementation of a pre-chamber combustion system allow for an increase in the efficiency of an internal combustion engine through optimizing its combustion process, while simultaneously reducing the engine-out emissions. The combination of alcohol-based fuels and pre-chamber combustion concepts has not been investigated on spark-ignition engines with high compression ratios in a passenger car size. This study presents investigations to show the potential in maximum achievable lean limit and net indicated efficiency. In particular, we present investigations of two alternative alcohol fuels on a direct-injection spark-ignition single-cylinder research engine for passenger car applications with a compression ratio of 16.4. The engine was operated with both an active and a passive pre-chamber, and the experimental results were compared to those of conventional spark-ignition operation. Direct injection was used for both the main combustion chamber and the pre-chamber. Methanol and ethanol were used as fuels for the main combustion chamber, whereas exclusively ethanol was used for the pre-chamber fueling. The performance of the alcohol fuels in all combustion configurations was evaluated in both part-load and high-load conditions. In particular, investigations of the combustion behavior over a variation of the excess air ratio at indicated mean effective pressures of 6 and 15 bar were performed. It can be concluded that with the use of methanol as fuel for the main combustion chamber, both higher excess air ratios and higher indicated efficiencies were achieved compared to the use of ethanol as the main combustion chamber fuel. In particular, a maximum net indicated efficiency of 48% at an excess air ratio of 2.0 was achieved with methanol. Moreover, active pre-chamber operation extended the lean limit to an excess air ratio of 2.3 compared to the maximum lean limit of 1.7 in passive pre-chamber operation.

TRENDS OF DIVERSIFICATION OF POWER CARRIERS OF MACHINE UNITS

From the point of view of environmental protection, the development of vehicles and their drives is determined in the future by the constant tightening of exhaust gas requirements. In addition, measures to reduce fuel consumption and CO2 emissions are increasingly influencing the concept of vehicle and drive optimization. Since most of the world's energy consumption is taken by transport, mainly cars, manufacturers are often faced with the need to develop and implement new, increasingly energy efficient and environmentally friendly energy methods - for example, the use of unconventional fuels, including: alcohol fuels (ethanol and methanol), biodiesel, Fischer's fluid -Tropsch, hydrogen fuel. So, the long-term guaranteed supply of transport energy, together with sound fuel management, ensures the medium and long-term diversification of energy for its production, especially, including alternative and renewable energy. Much has happened over the past decade, although policy goals remain unchanged for many countries improving energy security and limiting greenhouse gas emissions may be more important than ever. And, unprecedentedly, energy use in transportation is at the heart of these issues. New methods are needed to free transport from its persistent dependence on oil and take a new path. But technology has made interesting progress, and this progress will continue in the coming years, creating new opportunities to achieve these goals. Unsurprisingly, interest in biofuels and their production has skyrocketed over the past decade. Global production of total ethanol doubled between 1990 and 2021. In some regions, especially in Europe, the use of biofuels for diesel engines has also increased significantly in recent years. Perhaps most importantly, countries around the world are now seriously considering increasing the production and use of biofuels, and many countries have formulated policies to ensure this growth.

Effect Methanol, Ethanol, Butanol on the Emissions Characteristics of Gasoline Engine

The increasing volume of motorized vehicles leads to an increase in dependence on fossil fuels and an increase in air pollution. The problem can be reduced by utilizing renewable alcohol fuels such as methanol, ethanol, and butanol. The high number of octane and oxygen content is the main reason. Therefore, this study aims to observe the exhaust emissions of the 160 cc gasoline engine with a mixture of methanol, ethanol, and butanol. The percentage of alcohol used is 0 % to 30 % by volume. The test was carried out in 2000, 3000, and 4000 rpm. The results of the study explained that the use of methanol, ethanol, butanol in the fuel mixture was proven to reduce exhaust emissions. CO and HC emissions decreased as the percentage of alcohol in the fuel increased. The highest reduction in CO and HC emission in methanol blended fuel was 30 %, 94.55 % and 82.71 %, respectively. Meanwhile, CO2 emissions increased by 34.88 % at 2000 rpm engine speed. Based on this test, the addition of methanol to fuel can reduce exhaust emissions better than ethanol and butanol.

Influence of Short Carbon-Chain Alcohol (Ethanol and 1-Propanol)/Diesel Fuel Blends over Diesel Engine Emissions

Oxygenated fuels, in this case short carbon-chain alcohols, have been investigated as alternative fuels to power compression ignition engines. A major advantage of short-chain alcohols is that they can be produced from renewable resources, i.e., cultivated commodities or biomass-based biorefineries. However, before entering the market, the effects of short-chain alcohols on engine performance, exhaust emissions, noise and sound quality need to be understood. This work sheds light on the relationship between the physicochemical properties of the alcohol/diesel fuel blends (ethanol and 1-propanol) on engine performance, exhaust emissions and, for the first time, on noise and sound quality. It has been demonstrated that when the content of alcohol in blends increased, soot and soluble organic material emissions drastically decreased, mainly due to the increase of oxygen content in the fuel. Reduction in soot emissions combined with higher thermodynamic efficiency of alcohol fuels, with respect to diesel fuel, enable their utilization on compression ignition engines. There is also an improvement in the soot-NOx trade off, leading to large reductions on soot with a small effect on NOx emissions. The oxygen content within the fuel reduces CO and THC emissions at extra-urban driving operation conditions. However, hydrocarbons and CO emissions increased at urban driving conditions, due to the high heat of vaporization of the alcohol fuels which reduces cylinder temperature worsening fuel atomization, vaporization and mixing with air being more significant at lower cylinder temperature conditions (low engine loads and speeds). Similarly, the higher the presence of alcohol in the blend, the higher the noise emitted by the engine due to their low tendency to auto-ignition. The optimization of alcohol quantity and the calibration of engine control parameters (e.g., injection settings) which is out of the scope of this work, will be required to overcome noise emission penalty. Furthermore, under similar alcohol content in the blend (10% v/v), the use of propanol is preferred over ethanol, as it exhibits lower exhaust emissions and better sound quality than ethanol.

Pt Nanoparticles on Carbon Nanodots-Titania Composite for Enhanced Electro Oxidation of Alcohol Fuels

The severe corrosion of carbon supports in harsh fuel cell conditions has attracted the development of ceramic-based catalyst supports. Platinum nanoparticles supported on the carbon nanodots (CNDs)-titania (TiO2) composite were synthesized in three steps: Firstly, an inorganic support, titania (TiO2) was synthesized by a hydrolysis method. Secondly, the (CNDs-titania) nanocomposite support was prepared by sonicating pre-synthesized carbon nanodots (CNDs) and TiO2 in equal volumes of ethylene glycol/water solution. Lastly, nanosized Pt particles were deposited onto the CNDs-titania composite by a polyol method to form a platinum/(CNDs-titania nanocatalyst. X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), and X-ray difractommetry (XRD) were used to study surface morphology of the synthesized materials. Platinum loading onto the (CNDs-titania) composite support was quantified by ICP-OES. The electrooxidation of alcohol fuels was investigated in acidic electrolytes using chronoamperometric and voltammetric techniques. It was noted that the addition of TiO2 increases electroactivity of the nanocatalysts. The platinum/(CNDs-titania) nanocatalyst exhibited superior electroactivity during methanol and ethanol electrooxidation compared to the platinum/CNDs and Pt/C benchmark standards. Chronoamperometry (CA) curves showed that the platinum/(CNDs-titania) nanocatalyst exhibited outstanding anti-poisoning properties relative to the platinum/CNDs and commercial Pt/C nanocatalysts.