Effects of Open-Valve and Close-Valve Injections on the Performance of a Port Injection Methane Engine

Increasing concerns over energy security and stricter legislation on automotive exhaust emission limits have triggered greater efforts in utilizing alternatives to petroleum-based fuels. Compressed natural gas (CNG) is one of the promising candidates in terms of emissions and price. In this paper, methane, the major constituent of natural gas (NG), in used to fuel a Ricardo E6 engine and run in a port injection operation with open-valve and close-valve injection. The compression ratio is set at 10.5:1. Methane at 30 bar was supplied to the injector and injection length was adjusted to achieve the desired air fuel ratio (AFR). The minimum advance for best torque (MBT) was determined for 1100 rpm speed by measuring the indicated mean effective pressure (IMEP) for combustion at spark advance between 14°CA and 35°CA BTDC. The result is clearly demonstrated that the performance of the open valve port injection (OVPI) is superior to the one of the close valve port injection (CVPI) with better IMEP, fuel conversion efficiency, indicated power and volumetric efficiency. The observation indicates that OVPI shows steadiness of peak pressures shifts toward top dead centre (TDC) as spark ignitions were advanced compared to CVPI. In terms of combustion characteristics, the OVPI operation yields shorter ignition delay and overall burning duration even at the same phasing angle. Therefore, the open valve operation is preferable for NG port injection due to the fact that injections take place while intake valve is open. It accelerates the charge flow into the cylinder causing higher volumetric efficiency and avoiding the back pressure that happen when high pressure methane is injected while intake valve closes

Fuel injection responses and particulate emissions of a crdi engine fueled with cocos nucifera biodiesel

The objective of this paper is to study the effect of coconut oil biodiesel (COB)-diesel blends on exhaust particulate matter (PM) emissions and fuel injection responses in an unmodified turbocharged four-stroke common-rail direct injection (CRDI) diesel engine. Characterization of COB and their blends has been conducted to ascertain the applicability of these fuels for the existing engine. The test fuels used were fossil diesel fuel, COB10, COB20, COB30 and COB50 of biodiesel-diesel fuels. A test cycle which composed of 16 different steady-state modes at various loads and speed conditions was followed. Generally, the results showed a marginally advanced SOI timing and longer injection duration with increasing COB blends at higher load as compared to diesel fuel. Additionally, the lower calorific value (CV) and higher viscosity of the COB fuel blends have resulted in reduced turbo boost pressure and increased common-rail fuel injection pressure, respectively, across all engine speeds and loads. On the aspects of PM emissions characterization, results indicated that the blending of COB with conventional diesel had benefits over diesel in PM reduction. In fact, the largest achievable PM mass reduction of 38.55% was attained with COB50. In addition, it was noticed that the size of PM particles accumulated such that the granular size increased with higher diesel content in the blend. Additionally, the composition analysis on the PM collected by EDX spectroscopy has revealed that the C, O and Si as three main elements that made up the PM particles in descending order. Overall, the results indicated that COB biodiesel is a clean-burning alternative fuel and can be used satisfactorily in an unmodified diesel engine without the needs for engine remapping

Optimization of fuel injection parameters of moringa oleifera biodiesel-diesel blend for engine-out-responses improvements

Biodiesel has gained popularity in diesel engines as a result of the rapid decline of fossil fuels and population growth. The processing of biodiesel from non-edible Moringa Oleifera was investigated using a single-step transesterification technique. Both fuels had their key physicochemical properties measured and investigated. In a common-rail diesel engine, the effects of MB50 fuel blend on the symmetric characteristics of engine-out responses were evaluated under five load settings and at 1000 rpm. As compared to standard diesel, MB50 increased brake thermal efficiency (BTE), and nitrogen oxides (NOx) emissions while lowering brake specific fuel consumption (BSFC), and smoke emissions for all engine loads. A further study of injection pressure and start of injection (SOI) timing for MB50 fuel was optimized using response surface methodology (RSM). The RSM optimization resulted in improved combustion dynamics due to symmetry operating parameters, resulting in a simultaneous decrease in NOx and smoke emissions without sacrificing BTE. RSM is an efficient optimization method for achieving optimal fuel injection parameter settings, as can be deduced. As a result, a clearer understanding of the use of MB50 fuel in diesel engines can be given, allowing for the best possible engine efficiency

Fuel injection parameters study for low exhaust emissions of a common-rail diesel engine fueled with different biodisesels' blend / How Heoy Geok

Nowadays, the use of diesel engines is increasing rapidly due to their superior fuel economy, higher efficiency and excellent reliability. The energy crisis of fossil fuel depletion, rising price of diesel and environmental degradation have triggered a search for clean, sustainable and alternative fuels for internal combustion engines. Biodiesel is one of the most promising alternative fuels because it is a biodegradable, non-toxic and renewable fuel. This research aims to produce biodiesel from different feedstock such as coconut, calophyllum inophyllum and moringa oleifera oil and tested in a medium-duty four-cylinder diesel engine. In addition, the in-house produced coconut biodiesel was also used in the study of the effects of biodiesel blends, fuel injection timing, split injection schemes, injection dwell angle and mass ratio on the engine performance, emissions and combustion characteristics. At the first stage, a detailed investigation and characterization of key physicochemical properties were carried out. This was followed by the investigation of the effects of the usage of all these biodiesel blends on engine performance, emissions, exhaust particulate matter and combustion under different engine operating conditions. At second stage, parametric studies relating with start of injection timing variation and multiple injection schemes using COB20 and COB50 blends were performed and benchmarked with petroleum diesel fuel as baseline. At the final stage, the impact of two-stage injection dwell angle and mass ratio on engine performance, emissions and combustion characteristics using coconut biodiesel blends were investigated. The results showed that all biodiesel fuels and its blends have physicochemical properties relatively close to those of petroleum diesel. The experimental results also suggested that there are some penalties in engine brake power, brake specific fuel consumption (BSFC), and nitrogen oxide (NOx) blends with the presence of biodiesel fuel in the blend. The second stage experimental results revealed that a remarkably lower NOx level below 100 ppm can be obtained by retard SOI timing for both of the COB20 and COB50 fuel operations and with triple injection scheme. Multiple split injections is a practical strategies to simultaneously decrease NOx and smoke emissions when the SOI timing is fine-tuned and is an ideal alternative to operate with biodiesel fuel. For the last stage experiment, the results showed that exhaust emissions, engine performance and combustion characteristics are substantially affected by types of fuel and SOI timing but slightly influenced by two-stage injection dwell angle. Also, a considerably lower level of NOx below 90 ppm is achievable via late SOI timing for fuel operations conducted using COB20 or COB50 biodiesel blends with injection mass ratio of 25:75. Overall, the results indicated that biodiesel from coconut, calophyllum inophyllum and moringa oleifera oil can be used satisfactorily in the modern high-pressure common-rail diesel engine without modification. Besides, the results revealed that multiple and two-stage fuel injection with different mass ratio and dwell angle are practical strategies to simultaneously decrease NOx and smoke emissions when the SOI timing is fine-tuned and is an ideal alternative to operate with biodiesel fuel

Alexandrian Laurel for Biodiesel Production and its Biodiesel Blends on Performance, Emission and Combustion Characteristics in Common-Rail Diesel Engine

A two-step transesterification process was employed in the biodiesel production from non-edible Alexandrian Laurel. The key physicochemical properties of the Alexandrian Laurel biodiesel (ALB), diesel and blends of both fuels were compared and analyzed. The effects of blending biodiesel (ALB) and petroleum diesel on engine performance, combustion and exhaust emissions were investigated in a turbocharged, high-pressure common-rail diesel engine under six different speed operations and at full load conditions. The test fuels comprised a conventional diesel fuel and four different fuel blends of ALB. The results showed relatively close physicochemical properties of ALB and its blends when compared with petroleum diesel. However, the use of ALB-blended fuel resulted in penalties engine brake power, brake specific fuel consumption (BSFC) despite slightly improved brake thermal efficiency (BTE). Brake specific nitrogen oxide (BSNOx) was found worsened with higher ALB content in the blends. Nonetheless, consistent improvements in brake specific carbon monoxide (BSCO), brake specific carbon dioxide (BSCO2), and smoke were noticed when ALB blends were used. Additionally, ALB blends contributed to reduction in peak combustion pressure, peak heat release rate (HRR) and combustion duration. In general, the findings suggest satisfactory operation with ALB biodiesel-diesel blends in an unmodified diesel engine

A Study on the Tribological Performance of Nanolubricants

In recent years, the tribology field has expanded with the advent of nanolubrication. Nanolubricants are the name given to the dispersion of nanoparticles in a base oil, and has attracted researchers due to its potential application. In addition to being used in the tribology field, nanoparticles are also used for medical, space, and composites purposes. The addition of nanoparticles in base oils is promising because it enhances specific tribological characteristics including wear-resistance and friction, and the most important reason is that the majority of them are environmentally friendly. This paper reviews the tribological effect of various nanoparticles as lubricant additives. Parameters of nanoparticles that affect tribological performance, the technique to enhance stability, and lubrication mechanism that is currently believed to function will be delineated in detail. Moreover, this review facilitates an understanding of the role of various nanoparticles, which helps in developing and designing suitable nanolubricants for various applications

Performance, Emissions, Combustion and Vibration Analysis of a CI Engine Fueled with Coconut and Used Palm Cooking Oil Methyl Ester

Biodiesels from coconut and palm cooking oil are viable alternatives to diesel fuel due to their environmental sustainability and similar physicochemical properties compared to diesel. In the present study, these fuels were tested separately in a diesel engine by blending with fossil diesel in proportions of 10%, 20%, 30% and 40% by volume. Experiments were conducted under a constant brake mean effective pressure (BMEP) of 400 kPa and at 2000 rpm. The results revealed similarities in engine performance, emissions, combustion and engine block vibration for used palm cooking oil methyl ester (UPME) fuel blends and coconut methyl ester (CME) fuel blends. Most blends resulted in slight improvements in brake specific energy consumption (BSEC) and brake thermal efficiency (BTE). A maximum reduction of 54%, 89% and 16.8% in pollutant emissions of brake specific hydrocarbons (BSHC), brake specific carbon monoxide (BSCO) and brake specific nitrogen oxides (BSNOx), respectively, was observed with UPME and CME in the blends. The cylinder pressure profiles when UPME-diesel and CME-diesel blends were used were comparable to a standard diesel pressure trace, however, some deviations in peak pressure were also noticed. It was also apparent from the results that engine vibration was influenced by the type of methyl ester used and its blend composition. Notably, the rate of pressure increase was maintained within an acceptable limit when the engine was fueled with both of the methyl ester blends

An Experimental Investigation on the Characteristics of a Compression Ignition Engine Fuelled by Diesel-Palm Biodiesel–Ethanol/Propanol Based Ternary Blends

Issues such as rising fuel prices, fuel costs, and lowering reserves highlight the importance of research into sustainable fuels derived from biological sources. This study is focused on experiments on a CI engine using ethanol and propanol-based ternary blends. Palm biodiesel is kept constant at 40% volumetric concentration, while diesel and ethanol/propanol are varied in different batches. The results obtained with ternary blends were compared with reference fuel diesel, pure palm biodiesel, and a palm biodiesel–diesel binary blend. The ternary blends exhibit lower brake thermal efficiency and higher brake specific energy consumption than diesel and binary blends due to their lower calorific value. Despite in-fuel oxygen presence, lower brake specific oxides of nitrogen and smoke opacity were observed for engine operation with a ternary blend due to the predominant role of higher latent heat of vaporization and volatility of alcohols, but unburned hydrocarbon and carbon monoxide emissions increased due to the interactive effect of a lower cetane number, higher latent heat of vaporization, and lower kinematic viscosity of alcohols when compared to reference fuels. Among the tested fuels, in-cylinder pressure was observed to decrease with ternary blends due to their lower calorific value, but a raised heat release rate was attributed to lower viscosity and faster burning of alcohols