Advantages of converting Diesel engines to run as dual fuel ethanol–Diesel

Comparison of fuel economies of high efficiency diesel and hydrogen engines powering a compact car with a flywheel based kinetic energy recovery systems

Novel heavy duty engine concept for operation dual fuel H2–NH3

Advantages of the direct injection of both diesel and hydrogen in dual fuel H2ICE

This paper provides a comprehensive review and critical analysis of the latest research results in addition to an overview of the future challenges and opportunities regarding the use of hydrogen to power internal combustion engines (ICEs). The experiences and opinions of various international research centers on the technical possibilities of using hydrogen as a fuel in ICE are summarized. The advantages and disadvantages of the use of hydrogen as a solution are described. Attention is drawn to the specific physical, chemical, and operational properties of hydrogen for ICEs. A critical review of hydrogen combustion concepts is provided, drawing on previous research results and experiences described in a number of research papers. Much space is devoted to discussing the challenges and opportunities associated with port and direct hydrogen injection technology. A comparison of different fuel injection and ignition strategies and the benefits of using the synergies of selected solutions are presented. Pointing to the previous experiences of various research centers, the hazards related to incorrect hydrogen combustion, such as early pre-ignition, late pre-ignition, knocking combustion, and backfire, are described. Attention is focused on the fundamental importance of air ratio optimization from the point of view of combustion quality, NOx emissions, engine efficiency, and performance. Exhaust gas scrubbing to meet future emission regulations for hydrogen powered internal combustion engines is another issue that is considered. The article also discusses the modifications required to adapt existing engines to run on hydrogen. Referring to still-unsolved problems, the reliability challenges faced by fuel injection systems, in particular, are presented. An analysis of more than 150 articles shows that hydrogen is a suitable alternative fuel for spark-ignition engines. It will significantly improve their performance and greatly reduce emissions to a fraction of their current level. However, its use also has some drawbacks, the most significant of which are its high NOx emissions and low power output, and problems in terms of the durability and reliability of hydrogen-fueled engines.

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A Comprehensive Overview of Hydrogen-Fueled Internal Combustion Engines: Achievements and Future Challenges

This paper presents a new in-cylinder mixture preparation and ignition system for various gaseous fuels including hydrogen. The system consists of a centrally located direct-injection (DI) injector and a jet ignition (JI) device for combustion of the main chamber (MC) mixture. The fuel is injected in the MC with a new-generation, fast-actuating, high-pressure, high-flowrate DI injector capable of injection shaping and multiple events. This injector produces a bulk lean stratified mixture. The JI system uses a second DI injector to inject a small amount of fuel in a small pre-chamber (PC). A spark plug then ignites a slightly rich mixture. The MC mixture is then bulk ignited through multiple jets of hot reacting gases. Bulk ignition and combustion of the lean jet-controlled stratified MC mixture resulting from coupling DI with JI makes it possible to burn MC mixtures with fuel-to-air equivalence ratios reducing almost to zero for a throttleless control of load diesel-like and high efficiencies over almost the full range of loads. Computations are performed with hydrogen as the PC and MC fuel.

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Computational analysis of the lean-burn direct-injection jet ignition hydrogen engine

Jet ignition and direct fuel injection are potential enablers of higher-efficiency, cleaner internal combustion engines (ICEs), where very lean mixtures of gaseous fuels could be burned with pollutants formation below Euro 6 levels, efficiencies approaching 50 per cent full load, and small efficiency penalties operating part load. The lean-burn direct-injection (DI) jet ignition ICE uses a fuel injection and mixture ignition system consisting of one main-chamber DI fuel injector and one small jet ignition pre-chamber per engine cylinder. The jet ignition pre-chamber is connected to the main chamber through calibrated orifices and accommodates a second DI fuel injector. In the spark plug version, the jet ignition pre-chamber includes a spark plug which ignites the slightly rich pre-chamber mixture which then, in turn, bulk ignites the ultra-lean stratified main-chamber mixture through the multiple jets of hot reacting gases entering the in-cylinder volume. The paper uses coupled computer-aided engineering and computational fluid dynamics (CFD) simulations to provide better details of the operation of the jet ignition pre-chamber (analysed so far with downstream experiments or stand-alone CFD simulations), thus resulting in a better understanding of the complex interactions between chemistry and turbulence that govern the pre-chamber flow and combustion.

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Experimental and computational analysis of the combustion evolution in direct-injection spark-controlled jet ignition engines fuelled with gaseous fuels:

A Tempia

Papers

Computational analysis of the lean-burn direct-injection jet ignition hydrogen engine

Experimental and computational analysis of the combustion evolution in direct-injection spark-controlled jet ignition engines fuelled with gaseous fuels: