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Alternative fuels, such as natural and bio-gas, are attractive options for reducing greenhouse gas emissions from combustion engines. However, the naturally occurring variation in gas composition poses a challenge and may significantly impact engine performance. The gas composition affects fundamental fuel properties such as flame propagation speed and heat release rate. Deviations from the gas composition for which the engine was calibrated result in changes in the combustion phase, reducing engine efficiency and increasing fuel consumption and emissions. However, the efficiency loss can be limited by estimating the combustion phase and adapting the spark timing, which could be implemented favorably using a closed-loop control approach. In this paper, we evaluate the efficiency loss resulting from varying gas compositions and the benefits of using a closed-loop controller to adapt the spark timing to retain the nominal combustion phase.

The increasing need to reduce greenhouse gas emissions and shift away from fossil fuels has raised an interest for methanol. Methanol can be produced from renewable sources and can drastically lower soot emissions from compression ignition engines (CI). As a result, research and development efforts have intensified focusing on the use of methanol as a replacement for diesel in CI engines. The issue with methanol lies in the fact that methanol is challenging to ignite through compression alone, particularly at low-load and cold starts conditions. This challenge arises from methanol's high octane number, low heating value, and high heat of vaporization, all of which collectively demand a substantial amount of heat for methanol to ignite through compression.

The growing demand to lower greenhouse gas emissions and transition from fossil fuels, has put methanol in the spotlight. Methanol can be produced from renewable sources and has the property of burning almost soot-free in compression ignition (CI) engines. Consequently, there has been a notable increase in research and development activities directed towards exploring methanol as a viable substitute for diesel fuel in CI engines. The challenge with methanol lies in the fact that it is difficult to ignite through compression alone, particularly in low-load and cold start conditions. This difficulty arises from methanol's high octane number, relatively low heating value, and high heat of vaporization, collectively demanding a considerable amount of heat for methanol to ignite through compression. Previous studies have addressed the use of a pilot injection in conjunction with a larger main injection to lower the required intake air temperature for methanol to combust at low loads.

Automotive industry is a major contributor to global carbon dioxide (CO2) emissions and waste generation. Not only do vehicles produce emissions during usage, but they also generate emissions during production phase and end of life disposal. There is an urgent need to address sustainability and circularity issues in this sector. This paper explores how circularity and CO2 reduction principles can be applied to design and production of automotive parts, with the aim of reducing the environmental impact of these components throughout their life cycle. Also, this paper highlights the impact of design principles on End-of-Life Management of vehicles. As Design decisions of Component impacts up to 80% of emissions [1], it is important to focus on this phase for major contribution in reduction of emissions.

Throughout the world the efforts are being carried out to reduce the GHG emissions from transportation sector. As Volvo Group is a signatory of SBTi and having internal target of carbon neutrality by 2040, we have intensified & also diversified our R&D efforts to develop powertrains of the future having mix of conventional, various alternate fuels, electric etc. There will not be a unique solution or strategy suiting for all the markets in the world. Each market will have its own motivation & factors which OEMs need to consider while deciding the short term, midterm & long-term strategy for powertrain technology. Accordingly, OEMs must be ready with product mix suitable for all global markets. This paper will talk about the efforts taken and lessons learned during development of Hydrogen fuelled IC Engine. We used 8L Diesel IC engine as a base to convert it to Hydrogen powered IC engine, in a retrofit spirit, so that with minimum changes we could make the working prototype.

Pre-chamber ignition is one of the advanced technologies to improve the combustion performance for lean combustion natural gas engine, which could achieve low NOx, simultaneously. The designing scheme of the orifices, which connects the pre-chamber and the main chamber, is the main challenge limiting the further improvement. In this work, the three-dimensional computational fluid dynamics calculation based on a four-stroke engine with 320 mm cylinder bore was conducted to investigate the effects of orifice structure on the combustion and NOx performance. The results show that the schemes with 7 and 9 orifices lead to the delayed high-temperature jets formation due to the asymmetrical airflow in the pre-chamber, which retards the ignition timing but enhances the combustion in the main chamber. The 6 orifices scheme leads to the insufficient distribution of the high-temperature jets, and the 10 orifices result in the serious interference between the adjacent high-temperature jets.

The worldwide adoption of renewable energy mandates, together with the widespread utilization of biofuels has created a sharp increase in the production of biodiesel (fatty acid alkyl esters). As a consequence, the production of glycerol, the main by-product of the transesterification of fatty acids, has increased accordingly, which has led to an oversupply of that compound on the markets. Therefore, in order to increase the sustainability of the biodiesel industry, alternative uses for glycerol need to be explored and the production of fuel additives is a good example of the so-called glycerol valorization. The goal of this study is therefore to evaluate the suitability of a number of glycerol-derived compounds as diesel fuel additives. Moreover, this work concerns the assessment of low-concentration blends of those glycerol derivatives with diesel fuel, which are more likely to conform to the existing fuel standards and be used in unmodified engines.

Ammonia (NH3) is a carbon-free fuel, which could partially or completely eliminate hydrocarbon (HC) fuel demand. Using ammonia directly as a fuel has some challenges due to its low burning speed and low flammability range, which generates unstable combustion inside the combustion chamber. This study investigated the effect of two different compression ratios (CRs) of 10.5 and 12.5 on the performance of ammonia combustion by using a conventional single spark-ignition (SI) approach. It was found that at a lower CR of 10.5, the combustion was unstable even at advanced spark timing (ST) due to poor combustion characteristics of ammonia. However, increasing the CR to 12.5 improved the engine performance significantly with lower cyclic variations. In addition, this research work also observed the effect of multiple spark ignition strategies on pure ammonia combustion and compared it with the conventional SI approach for the same operating conditions.

A modern diesel engine is a reliable and efficient mean of producing power. A way to reduce harmful exhaust and greenhouse gas (GHG) emissions and secure the sources of energy is to develop technology for an efficient diesel engine operation independent of fossil fuels. Renewable diesel fuels are compatible with diesel engines without any major modifications. Rapeseed oil methyl esters (RME) and other fatty acid methyl esters (FAME) are commonly used in low level blends with diesel. Lately, hydrotreated vegetable oil (HVO) produced from vegetable oil and waste fat has found its way into the automotive market, being approved for use in diesel engines by several leading vehicle manufacturers, either in its pure form or in a mixture with the fossil diesel to improve the overall environmental footprint. There is a lack of data on how renewable fuels change the semi-volatile organic fraction of exhaust emissions.

Hybrid powertrain has been proven to be an effective fuel-saving technology in commercial vehicles, but many hybrid commercial vehicles still use conventional diesel engines, resulting in limited fuel savings. The main purpose of this study is to enhance the thermal efficiency of a dedicated hybrid diesel engine focusing on the characteristic operating conditions. Via fundamental thermodynamics process analysis of internal combustion engine, steel piston with high compression ratio, air system involving two-stage turbocharger(2TC) with an intercooler, and late intake valve closing(IVC) timing are proposed to improve the thermal efficiency of the engine. Experimental results show that high compression ratio and lower thermal conductivity of the combustion chamber surface lead to lower heat release rates, requiring optimization of piston profile to accelerate the mixing rate. Besides, high compression ratio also leads to higher mechanical losses.

An increasing need to lower greenhouse gas emissions, and so move away from fossil fuels like diesel and gasoline, has greatly increased the interest for methanol. Methanol can be produced from renewable sources and eliminate soot emissions from combustion engines [1]. Since compression ignition (CI) engines are used for the majority of commercial applications, research is intensifying into the use of methanol, as a replacement for diesel fuel, in CI engines. This includes work on dual-fuel set-ups, different fuel blends with methanol, ignition enhancers mixed with methanol, and partially premixed combustion (PPC) strategies with methanol. However, methanol is difficult to ignite, using compression alone, at low load conditions. The problem comes from methanol’s high octane number, low lower heating value and high heat of vaporization, which add up to a lot of heat being needed from the start to combust methanol [2].

A commercially available fuel, E85, a blend of ~85% ethanol and ~15% gasoline, can be a viable substitute for fossil fuels in internal combustion engines in order to achieve a reduction of the greenhouse gas (GHG) emissions. Ethanol is traditionally made of biomass, which makes it a part of the food-feed-fuel competition. New processes that reuse waste products from other industries have recently been developed, making ethanol a renewable and sustainable second-generation fuel. So far, work on E85 has focused on spark ignition (SI) concepts due to high octane rating of this fuel. There is very little research on its application in CI engines. Alcohols are known for low soot particle emissions, which gives them an advantage in the NOx-soot trade-off of the compression ignition (CI) concept.

Focusing on the dual-mode dual-fuel (DMDF) combustion concept, a combined optimization of the piston bowl geometry with the fuel injection strategy was conducted at low, mid, and high loads. By coupling the KIVA-3V code with the enhanced genetic algorithm (GA), a total of 14 parameters including the piston bowl geometric parameters and the injection parameters were optimized with the objective of meeting Euro VI regulations while improving the fuel efficiency. The optimal piston bowl shape coupled with the corresponding injection strategy was summarized and integrated at various loads. Furthermore, the effects of the key geometric parameters were investigated in terms of organizing the in-cylinder flow, influencing the energy distribution, and affecting the emissions. The results indicate that the behavior of the DMDF combustion mode is further enhanced in the aspects of improving the fuel economy and controlling the emissions after the bowl geometry optimization.

A feasible method was developed to reconstruct the three-dimensional flame surface of SI combustion based on 2D images. A double-window constant volume vessel was designed to simultaneously obtain the side and bottom images of the flame. The flame front was reconstructed based on 2D images with a slicing model, in which the flame characteristics were derived by slicing flame contour modeling and flame-piston collision area analysis. The flame irregularity and anisotropy were also analyzed. Two different principles were used to build the slicing model, the ellipse hypothesis modeling and deep learning modeling, in which the ellipse hypothesis modeling was applied to reconstruct the flame in the optical SI engine. And the reconstruction results were analyzed and discussed. The reconstruction results show that part of the wrinkled and folded structure of the flame front in SI engines can be revealed based on the bottom view image.

Automobile industry is facing challenges in the field of technological innovation and achieving minimum Total Cost of Ownership (TCO) despite rise in fuel prices. To overcome these challenges is certainly a challenging task. In doing so, automobile sector is mainly focused on passenger safety, comfort, reliability, meeting stringent emission norms, and above all reducing the vehicle fuel consumption. Referring to the Paris climate agreement, and India’s commitment to reduce the CO2 intensity by 33% - 35% by 2030 below the 2005 levels [1], it is imperative to lay down strong policies and procedure to curb the fuel consumption to contribute for reduction in carbon foot print and oil imports. Transportation sector is majorly responsible for the GHG Emission of which the CO2 emission from commercial vehicles is nearly 73% [2], although the total sales of commercial vehicles are around 4% of cumulative vehicle sales.

As the impacts of global warming have become increasingly severe, Oxy-Fuel Combustion (OFC) has been widely considered as a promising solution to reduce Carbon Dioxide (CO2) for achieving net-zero emissions. In this study, a one-dimensional simulation was carried out to study the implementation of OFC technology on a practical turbocharged 4-cylinder Gasoline Direct Injection (GDI) engine with economical oxygen-fuel ratios and commercial gasoline. When the engine is converted from Conventional Air-fuel Combustion (CAC) mode to OFC mode, and the throttle opening, oxygen mass fraction, stoichiometric air-fuel ratio (lambda = 1) are kept constant, it was demonstrated that compared to CAC mode, θF gets a remarkable extension whereas θC is hardly affected. θF and θC are very sensitive to the ignition timing, and Brake Specific Fuel Consumption (BSFC) would benefit significantly from applying Maximum Brake Torque (MBT) ignition timing.

The effect of an annular, piston bowl-rim cavity on in-cylinder and engine-out soot emissions is measured in a heavy-duty, optically accessible, single-cylinder diesel engine using in-cylinder soot diagnostics and exhaust smoke emission measurements. The baseline piston configuration consists of a right-cylindrical bowl, while the cavity-piston configuration features an additional annular cavity that is located below the piston bowl-rim and connected to the main-combustion chamber through a thin annular passage, accounting for a 3% increase in the clearance volume, resulting in a reduction in geometric compression ratio (CR) from 11.22 to 10.91. Experiments using the cavity-piston configuration showed a significant reduction of engine-out smoke ranging from 20-60% over a range of engine loads.

The major drivers in the development of the latest generation of engines are environmental. For diesel engines, mitigating the effects of soot contamination remains a significant factor in meeting these challenges. There is general consensus of soot impacting oil performance. Considerable efforts have been made towards a greater understanding of soot-lubricant interaction and its effects on engine performance. However, with evolution of engine designs resulting in changes to soot composition/ properties, the mechanisms of soot-lubricant interaction in the internal combustion engine continue to evolve. A variety of mechanisms have been proposed to explain soot-induced wear in engine components. Furthermore, wear is not the only topic among researchers. Studies have shown that soot contributes to oil degradation by increasing its viscosity leading to pumpability and lubricant breakdown issues.

In this study, a new system of assessment method was developed to evaluate the characteristics of urban buses based on remote online monitoring. Four types of buses, including China V emission standards diesel bus, lean-burn CNG bus, air-fuel equivalence ratio combustion CNG bus and gas-electric hybrid bus, were chosen as samples to analyze the emission characteristics of urban buses with different engine types in urban scenario. Based on the traffic conditions in Beijing, the actual emission characteristics of buses under newly-built driving conditions were analyzed. Moreover, the emission factor database of urban buses in Beijing was established to analyze the characteristics of excess emission. The research results are shown as follows. 1) Compared with other types of buses, NOX emission factor and emission rate of lean-burn CNG bus are much higher.

Engine and vehicle tailpipe emissions can be measured in laboratories equipped with engine dynamometers and chassis dynamometers, respectively. In addition to laboratory testing, there is an increase in interest to measure on-road vehicle emissions using portable emissions measurement systems in order to determine real-driving emissions. Current methods to quantify engine, vehicle tailpipe, and real-driving emissions include the raw continuous, dilute continuous, and dilute bag measurement methods. Although the dilute bag measurement method is robust, recent improvements to the raw and dilute continuous measurement methods can account for the time delay between the probe tip and analyzer in addition to gas transport dynamics in order to reliably recover the tailpipe concentration signals. These improvements significantly increase the reliability of results using the raw and dilute continuous measurement methods, making them possible alternatives to the bag method.