A novel one-dimensional multiphase and multicomponent spray model - hereafter referred to as the Kattke-Weigand model - has been developed to predict the penetration length of both vapor and liquid gasoline sprays under flash-boiling conditions, such as superheated injections. Its formulation is based on mass and momentum equations for unsteady jets and is therefore capable of capturing dynamic effects. Experiments were conducted in a constant volume chamber using various ambient and fuel temperature conditions and a six-hole GDI injector with a separated jet. Macroscopic spray parameters were extracted from the measurements to verify the model's ability to predict both liquid and vapor penetration length and the corresponding spray angles. Apart from the separated jet of the injector used, the other five jets interact strongly with each other under flash boiling conditions, resulting in spray collapse and thus affecting spray characteristics.
The combustion of fossil-based fuels in ICEs, resulting in a huge amount of greenhouse gases (GHG) and leading to an immense global temperature rise, are the root causes of the more stringent emission legislations to safeguard health and that encourage further investigations on alternative carbon-neutral fuels. In this respect, the hydrogen has been considered as one of the potential clean fuels because of its zero-carbon nature. The current development of hydrogen-based ICEs focuses on the direct injection (DI) strategy as it allows better engine efficiency than the port fuel injection one. The fuel jet behavior is a fundamental aspect of the in-cylinder air-fuel mixing ratio, affecting the combustion process, the engine performances, and the pollutants emissions. In the present study, comprehensive investigations on the hydrogen jet behavior, generated by a Compressed Hydrogen Gas (CHG) outward opening injector under different operative conditions, were performed.
Injector nozzle deposits can have a profound effect on particulate emissions from vehicles fitted with Gasoline Direct Injection (GDI) engines. Several recent publications acknowledge the benefits of using Deposit Control Additives (DCA) to maintain or restore injector cleanliness and in turn minimise particulates, but others claim that high levels of DCA could have detrimental effects due to the direct contribution of DCA to particulates, that outweigh the benefits of injector cleanliness. Much of the aforementioned work was conducted in laboratory scenarios with model fuels. In this investigation a fleet of 7 used GDI vehicles were taken from the field to determine the net impact of DCAs on particulates in real-world scenarios. The vehicles tested comprised a range of vehicles from different manufacturers that were certified to Euro 5 and Euro 6 emissions standards.
It is widely recognized that internal combustion engines (ICE) are needed for global transport for years to come, however, demands on ICE fuel efficiency, emissions, cost, and performance are extremely challenging. Gasoline compression ignition (GCI) is one approach to achieving demanding efficiency and emissions targets. At Aramco Research Center-Detroit, an advanced, multi-cylinder GCI engine was designed and built using the latest combustion system, engine controls, and lean aftertreatment. The combustion system uses Aramco's PPCI-diffusion process for ultra-low NOx and smoke. A P2 48V mild hybrid system was integrated on the engine for braking energy recovery and improved cold starts. For robust low-load operation, a 2-step valvetrain system was used for exhaust rebreathing. The fuel injection system was a modified diesel system with high injection rate and 2000 bar pressure rating.
The passive pre-chamber is valued for its jet ignition and is widely used in the field of gasoline direct injection (GDI) for small passenger cars, which can improve the performance of lean combustion. However, the scavenging and ignition combustion stability of the engine at low speed is a shortcoming that has not been overcome. Simply changing the structural design to increase the fluidity of MC and PC may lead to a reduction in jet ignition performance, which in turn will affect engine dynamics. This investigation is based on a non-uniformly nozzles distributed passive pre-chamber, which is adjusted according to the working fluid exchange between PC and MC. The advantages and disadvantages of the ignition mode of PC and SI in the target engine speed range are compared through optical experiments on a small single cylinder GDI engine. The results show that with the increase of λ from 1.0 to 1.6, the promotion effect of PCJI on load performance gradually decreases.
Ammonia (NH3), a zero-carbon fuel, has great potential for internal combustion engine development. However, its high ignition energy, low laminar burning velocity, a narrow range of flammability limits, and high latent heat of vaporization are not conducive for engine application. This paper numerically investigates the feasibility of utilizing ammonia in a heavy-duty diesel engine, specifically through the method of low-pressure direct injection (LP-DI) of hydrogen to ignite ammonia combustion. The study compares the engine's combustion and emission performance by optimizing four critical parameters: excess air ratio, hydrogen blending ratio, ignition timing, and hydrogen injection timing. The results reveal that excessively high hydrogen blending ratios lead to an advanced combustion phase, resulting in a reduction in indicated thermal efficiency.
A DMS500 engine exhaust particle size spectrometer was employed to characterize the effects of injection strategies on particulates emissions from a turbocharged gasoline direct injection (GDI) engine. The effects of operating parameters (injection pressure, secondary injection ratio and secondary injection end time) on particle diameter distribution and particle number density of emission was investigated. The experimental result indicates that the split injection can suppress the knocking tendency at higher engine loads. The combustion are improve, and the fuel consumption are significantly reduce, avoiding the increase in fuel pump energy consumption caused by the 50 MPa fuel injection system, but the delayed injection increases particulate matter emissions.
Net-Zero emission ambitions coupled with availability of oxygenated fuels like ethanol encouraged the Government towards commercial implementation of fuels like E20. In this background, a study was taken up to assess the impact of alcohol blended fuels on performance and emission characteristics of a BS-VI complaint motorbike. A single cylinder, 113-cc spark ignition, ECU based electronic fuel injection motorbike was used for conducting tests. Pure gasoline (E0), 10% ethanol-gasoline (E10), 20% ethanol-gasoline (E20) and 15% methanol-gasoline (M15) blends meeting respective IS standards were used as test fuels. The oxygen content of E10, E20 and M15 fuels were 3.7%, 7.4% and 8.35% by weight respectively. Experiments were conducted following worldwide motorcycle test cycle (WMTC) as per AIS 137 standard and also wide-open-throttle (WOT) test cycle, using chassis dynamometer.
World is moving towards cleaner, greener and energy efficient fuels. The increase in fuel consumption in various industries, especially in road transport sector has created interest for the blending of biofuels in conventional fuel and renewable fuels. Among biofuels ethanol is one of them and preferable choice for blending in gasoline which is a fuel for spark ignition engines and flex fuel vehicles. As such ethanol/methanol cannot be used in compression-ignition diesel engines without engine modifications due to inherent low cetane number and lubricity of alcohols. Therefore, fuel consisting of certain concentrations of alcohols such as methanol / ethanol in diesel blends is being promoted. The lower alcohols (methanol/ethanol) are not miscible in diesel due to their polarity differences. An additive package is essential for the solubility and stability of alcohol (methanol/ethanol) in diesel phase or diesel blends.
Modern problem-solving techniques have enabled the lives of engineers to find better solutions even for the most complex problems in the most innovative way. One such technology widely being used in the modern automotive industry is TRIZ, a Russian acronym for the "Theory of Inventive Problem Solving, The main objective of this study is to find an optimum solution to enhance the life of a 2.2-liter automotive diesel engine which has faced challenges of extinction due to the system technology upgrades that happened on Fuel Injection System. It has become a mandate to find an innovative solution that helps to improve performance and efficiency and to reduce cost, weight, size, complexity and manufacturability. With the help of detailed Functional analysis, Cause and Effect Chain analysis, absolute analysis was done in selecting the optimum FIE System for the engine application.
Ultra-lean combustion of GDI engines could achieve a higher thermal efficiency and lower NOx emissions, but it also faces challenges such as ignition difficulties and a low-speed flame propagation. In this paper, the sparked-spray is proposed as a novel ignition method, which employs the spark to ignite the fuel spray by the cooperative timing control of in-cylinder fuel injection and spark ignition, and form a jet flame, and then the jet flame fronts propagate in the ultra-lean premixed mixture in the cylinder. This combustion mode is named Sparked-Spray Induced Combustion (SSIC) in this paper. Based on a 3-cylinder 1.0L GDI engine, a 3D simulation model is established in the CONVERGE to study the effects of ignition strategy, compression ratio, injection timing, equivalent ratio on SSIC with global equivalent ratio of 0.50.
The pressing need for carbon-neutral transportation solutions has never been more pronounced. With the continually expanding volume of goods in transit, innovative and dependable powertrain concepts for freight transport are imperative. The green hydrogen-powered internal combustion engine presents a compelling avenue for integrating a reliable, non-fossil fuel powertrain into commercial vehicles. This study focuses on the adaptation of a single-cylinder diesel engine with a displacement of 2116 cm³ to facilitate hydrogen combustion. The engine, characterized by low levels of swirl and tumble, underwent modifications, including the integration of a conventional central spark plug, a custom-designed piston featuring a reduced compression ratio of 9.6, and a low-pressure hydrogen direct injection system. Operating the injection system at 25 bar hydrogen pressure, the resulting jet profiles were varied by employing jet-forming caps affixed directly to the injector nozzle.
Aluminum alloy has become an indispensable part of the automotive industry because of its excellent mechanical properties such as lightweight, high strength, high reliability, maintainability, and low cost. Aluminum alloy is used in automobiles, such as engine blocks, cylinder heads, intake manifolds, brake components, and fuel tanks. Fatigue and fracture are the main reasons for its engineering failure. Surface strengthening techniques, such as ultrasonic shot peening (USP), are often used to improve the fatigue resistance of aluminum alloys. This article expounds on the working principle of ultrasonic shot peening and elucidates the influence of USP process parameters on the surface characteristics of aluminum alloy. Experimental results observed the effects of USP parameters on surface properties such as surface roughness, microhardness, and surface morphology.
In-cylinder fluid dynamics enhance performance and emission characteristics in internal combustion (IC) engines. Techniques such as helical ports, valve shrouding, masking, and modifications to piston profiles or vanes in ports are employed to achieve the desired incylinder flows in these engines. However, due to space constraints, modifications to the cylinder head are typically minimal. The literature suggests that introducing baffles into the combustion chamber of an IC engine can enhance in-cylinder flows, air-fuel mixing, and, subsequently, stratification. Studies have indicated that the height of the baffles plays a significant role in determining the level of improvement in in-cylinder flow and air-fuel mixing. Therefore, this study employs Computational fluid dynamics (CFD) analysis to investigate the impact of baffle height on in-cylinder flow and air-fuel mixing in a four-stroke, four-valve, spray-guided gasoline direct injection (GDI) engine.