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Direct injection strategies have been successfully used on spark ignited internal combustion engines for improving performance and reducing emissions. Among the different technologies available, outward opening injectors seem to have found their place in renewable applications running on gaseous fuels, including natural gas or hydrogen, as well as in a few specific liquid fuel applications. In order to understand the key operating principles of these devices, their limitations and the resulting sprays, it is necessary to accurately describe the pintle dynamics. The pintle’s relative position with respect to the injector body defines the internal flow geometry and therefore the injection rates and spray characteristics. In this paper both numerical and experimental investigations of the dynamics of an outward opening injector pintle have been carried out.

Di-ethyl ether (DEE) belongs to the family of oxygenated fuels, which have been investigated as an alternative to conventional diesel. However, increasing the proportion of DEE in DEE-diesel blends changes its physicochemical properties. This work shows the non-evaporating and non-reacting spray characteristics of diesel, DEE20 (20% v/v DEE and 80% v/v diesel), and DEE40 (40% v/v DEE and 60% v/v diesel) were investigated. The effect of fuel injection pressure (FIP: 500 and 800 bar) on the spray morphology and droplet size distribution at different axial locations along the spray axis was done. FIP of 800 bar showed a reduction in Sauter mean diameter (SMD) of spray droplets with increasing axial distance due to improved spray atomisation because of the drag forces of the surrounding air on the fuel droplets. DEE20 showed a higher number of droplets having a smaller diameter than DEE40. DEE20 and DEE40 showed superior spray atomisation characteristics than diesel.

Considering the demand for sustainable transport, alternative fuels are a keen research topic for IC engine researchers. Among various alternative fuels being explored, Di-ethyl ether (DEE) is gaining popularity off-late for compression-ignition (CI) engines owing to its high cetane rating, oxygen presence in its molecular structure, and lower carbon content. This study explores the suitability of DEE blends in tractor engines. DEE blends [15% and 30% (v/v)] with diesel were compared with baseline diesel for combustion, and emission characterisation, keeping all parameters identical, including the fuel injection timings. Results were analysed for different engine loads at 1500 rpm. Delayed combustion was observed with DEE blends with diesel, possibly due to a higher cooling effect from DEE vaporisation and retarded dynamic fuel injection due to its higher compressibility. However, the DEE blend fuelled engine performance was comparable to baseline diesel.

Injector performance in gasoline Direct-Injection Spark-Ignition (DISI) engines is a key focus in the automotive industry as the vehicle parc transitions from Port Fuel Injected (PFI) to DISI engine technology. DISI injector deposits, which may impact the fuel delivery process in the engine, sometimes accumulate over longer time periods and greater vehicle mileages than traditional combustion chamber deposits (CCD). These higher mileages and longer timeframes make the evaluation of these deposits in a laboratory setting more challenging due to the extended test durations necessary to achieve representative in-use levels of fouling. The need to generate injector tip deposits for research purposes begs the questions, can an artificial fouling agent to speed deposit accumulation be used, and does this result in deposits similar to those formed naturally by market fuels?

Mixture formation in GDI engine is considered crucial in determining combustion and emissions characteristics, which mainly depend on fuel spray quality. However, spray characteristics change with variations in control parameters such as fuel injection parameters, fuel injection strategy, engine operating conditions, and fuel properties. Growing research interest in the use of methanol as an additive with gasoline has motivated the need for deeper investigations of spray characteristics of these fuels. Although, it can be noted that sufficient literature is available in the area of spray characterization under several independent influencing factors, however, comparative analysis of gasohol spray behavior under different ambient conditions is hardly studied.

Petroleum products are used to power internal combustion engines (ICEs). Emissions and depletion of petroleum reserves are important questions that need to be answered to ensure existence of ICEs. Indian Railways (IR) operates diesel locomotives, which emit large volume of pollutants into the environment. IR is looking for an alternative to diesel for powering the Locomotives. Methanol has emerged as a replacement for petroleum fuels because it can be produced from renewable resources as well as from non-renewable resources in large quantities on a commercially viable scale. It has similar/superior physico-chemical properties, which reduce tailpipe emissions significantly. It is therefore necessary to understand the in-cylinder phenomenon in methanol fueled engines before its implementation on a large-scale.

Alternative fuels, coupled with advanced engine technologies, are potential solutions to overcome energy crisis and environmental degradation challenges, that transport sector faces. Methanol has emerged as a potential candidate as an alternate fuel due to adequate availability of indigenous feedstocks, such as coal, biomass, and municipal solid waste (MSW). Policy makers of several countries are focusing on developing roadmap for methanol fueled vehicles, especially in developing countries like China and India. These countries have the largest two-wheeler market globally; therefore, methanol adaptability on 2-wheeler engine becomes important national priority. This study is aimed at feasibility assessment of methanol (M100) fueled two-wheeler engine using simulations. Present study was divided into four different phases.

Understanding and prediction of flash-boiling spray behavior in gasoline direct-injection (GDI) engines remains a challenge. In this study, computational fluid dynamics (CFD) simulations using the homogeneous relaxation model (HRM) for not only internal nozzle flow but also external spray were evaluated using CONVERGE software and compared to experimental data. High-speed extinction imaging experiments were carried out in a real-size axial-hole transparent nozzle installed at the tip of machined GDI injector fueled with n-pentane under various ambient pressure conditions (Pa/Ps = 0.07 - 1.39). The width of the spray during injection was assessed by means of projected liquid volume, but the structure and timing for boil-off of liquid within the sac of the injector were also assessed after the end of injection, including cases with different designed sac volumes.

Depleting fossil-fuels and increasing harmful emissions by the combustion of fossil fuels in IC engine is a matter of great concern. It is necessary to explore solutions complying with the prevailing emission norms in different sectors. Methanol has the potential amongst all primary alcohols for widespread use in transport sector due to its clean-burning, high octane rating, sources of production like high ash coal, and biomass. The addition of methanol to gasoline can significantly reduce engine-out emissions. Gasoline-Methanol blends (Gasohols) can be used to reduce dependence of the transport sector on fossil fuels. This study deals with investigation of spray characteristics of methanol-gasoline blends as it affects engine performance and emissions characteristics to a great extent.

Fuel atomization and air-fuel mixing processes play a dominant role on engine performance and emission characteristics in a direct injection compression ignition engine. Understanding of microscopic spray characteristics is essential to predict combustion phenomena. The present work investigated near nozzle flow and atomization characteristics of biodiesel fuels in a constant volume chamber. Waste cooking oil, Jatropha, and Karanja biodiesels were applied and the results were compared with those of conventional diesel fuel. The tested fuels were injected by a solenoid injector with a common-rail injection system. A high-speed camera with a long distance microscopic lens was utilized to capture the near nozzle flow. Meanwhile, Sauter mean diameter (SMD) was measured by a phase Doppler particle analyzer to compare atomization characteristics.

Premixed charge compression ignition (PCCI) combustion is an advanced combustion technique, which has the potential to be operated by alternative fuels such as alcohols. PCCI combustion emits lower oxides of nitrogen (NOx) and particulate matter (PM) and results thermal efficiency similar to conventional compression ignition (CI) engines. Due to extremely high heat release rate (HRR), PCCI combustion cannot be used at higher engine loads, which make it difficult to be employed in production grade engines. This study focused on development of an advanced combustion engine, which can operate in both combustion modes such as CI combustion as well as PCCI combustion mode. This Hybrid combustion system was controlled by an open engine control unit (ECU), which varied the fuel injection parameters for mode switching between CI and PCCI combustion modes.

In this study, macroscopic spray characteristics of Waste cooking oil (WCO), Jatropha oil, Karanja oil based biodiesels and baseline diesel were compared under simulated engine operating condition in a constant volume spray chamber (CVSC). The high pressure and high temperature ambient conditions of a typical diesel engine were simulated in the CVSC by performing pre-ignition before the fuel injection. The spray imaging was conducted under absence of oxygen in order to prevent the fuels from igniting. The ambient pressure and temperature for non-evaporating condition were 3 MPa and 300 K. Meanwhile, the spray tests were performed under the ambient pressure and temperature of 4.17 MPa and 804 K under evaporating condition. The fuels were injected by a common-rail injection system with injection pressure of 80 MPa. High speed Mie-scattering technique was employed to visualize the evaporating sprays.

Biodiesel made from Jatropha oil by transesterification process has viscosity and other important physical properties comparable to mineral diesel hence it can be used as an alternate fuel in conventional diesel engines. It is important to investigate the spray characteristics of biodiesel because emissions from the engines are dependent on fuel atomization process and resulting fuel-air mixing. This study focuses on the Jatropha biodiesel spray investigations using Phase Doppler Interferometry (PDI) for measurement of various microscopic spray parameters such as Sauter mean diameter (SMD) and spray droplet size and velocity distributions. The spray and engine experiments were carried out for Jatropha biodiesel (JB100) and their 20% blends (JB20) with mineral diesel as baseline. Fuel injection pressure during the spray experiments was maintained at 200 bars for all tests, quite similar to small horse power agricultural engines, and the fuel injection quantity was varied.

The development of advanced gasoline direct injection (GDI) injector requires in-depth investigations of macroscopic and microscopic spray characteristics. Over the years, GDI injectors have undergone exponential improvement to be able to deliver fuel at high injection pressure. High fuel injection pressure (FIP) leads to superior fuel atomization, and consequently superior fuel-air mixing. Present investigations aim to improve our fundamental knowledge of the furl-air mixture preparation mechanisms of different test fuels. Experiments were conducted to study spray breakup of GDI injector. This study focuses on the spray investigations using Phase Doppler Interferometry (PDI) for the measurement of various spray related studies such as determination of arithmetic mean diameter (AMD), sauter mean diameter (SMD) and spray droplet velocity distributions.

Fuel injection pressure (FIP) is one of the most important factors affecting diesel engine performance and particulate emissions. Higher FIP improves the fuel atomization, which results in lower soot formation due to superior fuel-air mixing. The objective of this spray study was to investigate macroscopic and microscopic spray parameters in FIP range of 500-1500 bar, using a solenoid injector for biodiesel blends (KB20 and KB40) and baseline mineral diesel. For these test fuels, effect of ambient pressure on macroscopic spray characteristics such as spray penetration, spray area and cone angle were investigated in a constant volume spray chamber (CVSC). Microscopic spray characteristics such as velocity distribution of droplets and spray droplet size distribution were measured in the CVSC at atmospheric pressure using Phase Doppler Interferometry (PDI).

Ever tightening emission limits and constant pressure for increasing engine power are resulting in increased engine operating temperature. This coupled with continuous drive for fuel economy improvement because of the stiff competition are forcing OEMs to explore alternative cooling solutions resulting in less power take off and quick response as cooling requirement shoots up. Aim of this paper is to analyze the relative benefits of incorporating a new cooling fan drive system concept over conventional viscous fan driven cooling system with step-less variable speed control independent of engine speed variation. Hydraulic fan drive system control fan rpm based on the fluid temperature as compared to air temperature in viscous coupling fan drive system. HFD system provides quick response when increase in coolant temperature is observed. HFD system in this way provide more control on fan rpm.

Gasoline Direct Injection (GDI) engine is known for its higher power and higher thermal efficiency. Researchers are steadily determining and resolving the problems of fuel injection in a GDI engine. In order to meet the stringent emission norms such as PM and NOx emitted by a GDI engine, it is necessary to investigate the microscopic spray characteristics and fuel-air mixing process. This paper aims to share the fundamental knowledge of the interacting mixture preparation mechanisms at the wide range of fuel injection pressures. The investigations were carried out at five different fuel injection pressures viz: 40, 80, 120, 160, 200 bar, for 24 mg fuel per injection. A high speed CCD camera was used to determine the macroscopic spray characteristics of the GDI injector. It was found that spray penetration length increased with increasing fuel injection pressure. Phase Doppler Interferometry (PDI) was used to determine the droplet size and droplet velocity for different test fuels.

IC engines are facing two major challenges in the 21st century namely threat of fossil fuel depletion and environmental concerns. HCCI engine is an attractive solution to meet stringent emission challenges due to its capability to simultaneously reduce NOx and PM. HCCI technology can be employed with different alternative fuels without significant modifications in the existing engines. In this study, HCCI combustion was investigated using B20 (20% v/v biodiesel with diesel). Investigations were carried out on a two cylinder engine, in which one cylinder was modified to operate in HCCI mode however the other cylinder operated in conventional CI combustion mode. A dedicated fuel vaporizer was used for homogeneous fuel-air mixture preparation. The experiments were performed at three different intake charge temperatures (160°C, 180°C and 200°C) and three different EGR ratios (0%, 10% and 20% EGR) at different engine loads.

Better understanding of flow phenomena inside the combustion chamber of a diesel engine and accurate measurement of flow parameters is necessary for engine optimization i.e. enhancing power output, fuel economy improvement and emissions control. Airflow structures developed inside the engine combustion chamber significantly influence the air-fuel mixing. In this study, in-cylinder air flow characteristics of a motored, four-valve diesel engine were investigated using time-resolved high-speed Tomographic Particle Imaging Velocimetry (PIV). Single cylinder optical engine provides full optical access of combustion chamber through a transparent cylinder and flat transparent piston top. Experiments were performed in different vertical planes at different engine speeds during the intake and compression stroke under motoring condition. For visualization of air flow pattern, graphite particles were used for flow seeding.

The effect of biodiesel produced from waste cooking oil (WCO) on the soot particles in a compression ignition engine was investigated and compared with conventional diesel fuel. The indicated mean effective pressure of approximately 0.65 MPa was tested under an engine speed of 1200 revolutions per minute. The fuels were injected at an injection timing of −5 crank angle degree after top dead center with injection pressures of 80 MPa. Detailed characteristics of particulate matters were analyzed in terms of transmission electron microscopy (TEM), thermogravimetric analysis (TGA) and elemental analysis. Soot aggregates were collected on TEM grid by thermophoretic sampling device installed in the exhaust pipe of the engine. High-resolution TEM images revealed that the WCO biodiesel soot was composed of smaller primary particle than diesel soot. The mean primary particle diameter was measured as 19.9 nm for WCO biodiesel and 23.7 nm for diesel, respectively.