Fuel Injection Equipment Research Articles

Decreasing the wear of precision pairs of fuel injection equipment in diesel engines

Reliable operation of a diesel engine largely depends on wearing degree of joints and assemblies of fuel injection equipment. The precision components of the high-pressure fuel pump and nozzles are most susceptible to wear. The following methods are used to reduce the wear of precision pairs of a high-pressure fuel pump: increasing the hardness of the mating parts, improving the filtering quality of the fuel and increasing the fuel lubricity. From the point of implementing easiness and obtaining the greatest effect, the most promising is improving the lubricity of motor fuel. It is possible to increase the lubricity of motor fuels by using liquid fuels of biological origin or by introducing vegetable-based fluid into commercial mineral diesel fuel, for example, cameline oil. The fuel kinematic viscosity effect on the wear of the precision pairs of the fuel injection equipment in diesel engines is theoretically substantiated. The results of bench tests of a high-pressure fuel pump for wear of plunger pairs (inner cylinder - bush bearing) during operation with mixed cameline-mineral fuel are presented.

Performance and emission characterization of a common-rail compression-ignition engine fuelled with ternary mixtures of rapeseed oil, pyrolytic oil and diesel

Biofuels are one of the short-term alternatives for reducing the well-to-wheel greenhouse gas footprint of transport. In the framework of compression-ignition engine fuels. This study investigates the feasibility of using cold-pressed rapeseed oil as a biocomponent, admixed with distilled tyre pyrolytic oil, as an energy-efficient alternative to commonly considered methyl ester-based mixtures in diesel fuel. Selected ternary and binary fuel blends are subjected to engine tests. Their scope covers 80% of the engine map and aims at identifying tradeoffs between fuel composition, engine performance and emissions. The results show that fuel mixtures containing a large fraction of rapeseed oil (up to 55% by volume) can be effectively combusted when pyrolytic oil distillate is introduced as the additive. The deterioration in brake efficiency for such fuel does not exceed 1.2% with respect to diesel baseline. At the same time, the results are superior in terms of both efficiency and emissions when compared to FAME-based biodiesel. Finally, with indicated efficiencies on a similar level as the diesel baseline, suggesting improved burning rate with pyrolytic oil addition, the study identifies parasitic losses in fuel injection equipment as a significant contributor to the overall efficiency penalty for the examined ternary mixtures.

Improvement of Diesel Lubricity by Chemically Modified Tung-Oil-Based Fatty Acid Esters as Additives

Diesel fuel lubricity has been a concern of diesel fuel injection equipment manufacturers for many years. The problem has drawn attention because of the reduction in lubricity associated with the e...

Efficiency improvement of locomotive-type diesel engine operation due to introduction of resource-saving technologies for cleaning diesel and diesel locomotive systems

The influence of carbonic deposits on indices of diesel engine operation has been investigated. The technology of clean-in-place of fuel system, fuel injection equipment and cylinder-piston group of diesel locomotive engines using special cleaning agent has been developed on the basis of the analysis of mechanisms of the formation and accumulation of carbonic deposits on the parts and the elements of a diesel engine systems. The task concerning the choice of scientifically grounded terms of clean-in-place technology application has been solved relying on the experience of a developed mathematical model usage. The conclusion as to the possibility of making changes in the technology of maintenance and the increase of a diesel locomotive overhaul life has been made.

Impact of the Engine Tuning on its Technical Condition Assessment Based on Limited Number of Available Parameters

Abstract Due to the limited scope of the diagnostic equipment on the ship, the technical condition of the engine is based on the measurement of pressure and temperature at the available measuring points. Usually it is the exhaust temperature at the outlet of individual cylinders, supercharging pressure, oil temperature and cooling water temperature. Sometimes the bearing temperature and turbocharger speed are also measured. Normally, if the engine is adapted to this, the maximum combustion pressure is measured periodically although distorted through the channels with the indicator valves. The paper presents examples of the exploitation of marine diesel engines, where there is a discrepancy between the actual technical state of the engine and the technical state of the engine based on the traditional diagnostic method based on a limited set of available parameters. These discrepancies resulted, inter alia, from the regular fuel injection timing and fuel dose adjustment, so that the measured parameters were adequate to the actual load of the engine. This adjustment is justified, but leads to masking engine components wear symptoms. In this situation, it can only be stated that the state of the fuel injection equipment is suitable for the current technical state of the some engine components and does not provide a sufficient basis for the extension of the repair interval.

The influence of stick–slip transitions in mixed-friction predictions of heavily loaded cam–roller contacts

A load-sharing-based mixed lubrication model, applicable to cam–roller contacts, is developed. Roller slippage is taken into account by means of a roller friction model. Roughness effects in the dry asperity contact component of the mixed lubrication model are taken into account by measuring the real surface topography. The proportion of normal and tangential load due to asperity interaction is obtained from a dry contact stick–slip solver. Lubrication conditions in a cam–roller follower unit, as part of the fuel injection equipment in a heavy-duty diesel engine, are analyzed. Main findings are that stick–slip transitions (or variable asperity contact friction coefficient) are of crucial importance in regions of the cam where the acting contact forces are very high. The contact forces are directly related to the sliding velocity/roller slippage at the cam–roller contact and thus also to the static friction mechanism of asperity interactions. Assuming a constant asperity contact friction coefficient (or assuming that gross sliding has already occurred) in highly loaded regions may lead to large overestimation in the minimal required cam–roller contact friction coefficient in order to keep the roller rolling. The importance of including stick–slip transitions into the mixed lubrication model for the cam–roller contact is amplified with decreasing cam rotational velocity.

The Effect of Fuel Injection Equipment of Water-In-Diesel Emulsions on Micro-Explosion Behaviour

The number and size distributions of the water dispersed phase have a significant effect on both the long-term stability of an emulsion, and the probability of micro-explosions inside an engine. The emulsions are subjected to intense pressure and shear flow in the fuel injection equipment resulting in changes in the number and size distributions of the dispersed phase. These changes, in turn, have significant effects on the micro-explosion behavior of the droplets. To our knowledge, these effects are not known and have not been reported previously. To uncover some of these effects we carried out a comprehensive experimental investigation on an emulsion spray of 10% water (by volume) in diesel at different injection pressures of 500, 1000 and 1500 bar. A measurement system consisting of a high-speed camera was used to visualize the droplets’ micro-explosions and a thermocouple measured the temperature. Our measurements indicated that the emulsion shear in the injector nozzle shifted the emulsion droplet size distribution towards the smaller end resulting in a delay in the onset of micro-explosion. This delay in the onset of the micro-explosion is thought to be due to the decrease in the dispersed water coalescence rate which, in turn, increases the stability of the emulsion. The results also show that this delay in the onset of micro-explosion, and the temperature required for its onset, increased with injection pressure.

The effect of fuel injection equipment on the dispersed phase of water-in-diesel emulsions

Water-in-diesel emulsions are known to lead to micro-explosions when exposed to high temperatures, thereby offering a technology that could improve the mixing of fuels with the ambient gas. The number and size distributions of the dispersed phase have a significant effect on both the long-term stability of the emulsion and the probability of micro-explosion inside an engine. Although the elevated pressures, temperatures, and shear found in high-pressure pumps and common-rail injector nozzles are likely to alter the properties of emulsions, the effect of these engine components on the injected emulsion are not known. To address this issue we sampled an emulsion at several locations within the injection system, from the fuel tank to the injector nozzle, and measured the evolution of the droplet size distribution of the emulsion’s dispersed phase. We varied the water mass fraction (5, 10 and 15% by volume) of the emulsion and the injection pressure (500, 1000 and 1500 bar), imaged the samples using a high-resolution microscope and extracted the droplet size distribution using a purpose-built image processing algorithm. Our measurements reveal that the dispersed droplet sizes reduce significantly after the emulsion is compressed by the high-pressure fuel pump, and again after being injected through the nozzle’s orifices. Additionally, the dispersed droplet sizes measured from the pump’s return and injector return to the fuel tank were also smaller than the initial size, suggesting that the physical and calorific properties of the emulsion in the fuel tank can change significantly with time. Hence we propose that differences in injection equipment and engine testing duration may contribute to some of the disagreements in the literature regarding the effect of emulsified fuels on engine emissions and fuel efficiency. The engine performance and energy efficiency of vehicle fleets that use emulsified fuels will vary with engine running time, thus potentially inducing a drift in the engine performance and exhaust emissions. This investigation also suggests that, in order to be representative of actual injection conditions, fundamental studies of the micro-explosion of emulsion droplets should be performed using much smaller dispersed droplet sizes than those normally found in an unused emulsion.

Effect of non-edible oil and its biodiesel on wear of fuel injection equipment components of a genset engine

In this study, a fuel injection equipment (FIE) test rig was designed and fabricated to investigate the wear characteristics of FIE components used by a single cylinder diesel engine using Karanja oil (KO100), and Karanja biodiesel (KOME100) vis-a-vis baseline mineral diesel. A 250 h endurance test was performed in the FIE test rig to evaluate the wear, weight loss, dimensional loss and alterations to the surface texture at different locations in various components used in the FIE such as nozzle needle, plunger, valve and valve holder. Cam and follower mechanism was used for developing fuel injection pressure in the fuel pump of the test rig, which was operated at 1500 rpm. Karanja oil showed the lowest wear and mineral diesel showed the highest wear of the FIE components, except for plunger. The same was confirmed by surface texture images obtained by optical microscopy at magnifications of 100, 200 and 500×. Wear of FIE components took place primarily due to mechanical and thermal stresses, and chemical reactivity of test fuels with the FIE components. Overall, the wear of FIE components was relatively lower with biodiesel and SVO usage compared to baseline mineral diesel usage in the test rig.

The tribology of fructose derived biofuels for DISI gasoline engines

2-Methylfuran (MF) and 2,5-dimethylfuran’s (DMF) combustion characteristics have confirmed their validity as appropriate gasoline replacement and enhancement fuels. However, the performance of fuel injection equipment is dependant on the tribological performance of these fuels lubricity testing of MF, DMF and their blends with gasoline was undertaken using the high frequency reciprocating rig method, based on ASTM D6079 . Results showed that both MF and DMF possessed greater lubricity and wear resistance characteristics than those of gasoline when tested as pure substances. Their blends with gasoline at 2, 4, 6, 8, 10, 20 and 50 percent volume (%vol) showed improved tribological performance also. DMF was found to possess greater lubricating properties than that of MF. As little as 2%vol reduced the wear scar diameter by 46% and 47% for MF and DMF respectively showing even a small addition of these biofuels could greatly improve the tribological performance of the fuel within the engine. This was mainly due to the polar functional groups of MF and DMF bonding to the bearing surfaces during testing, creating a tribo-film that protected the surface, reducing both wear and friction. These effects were greatest for the DMF blends, with two methyl groups leading to stronger polarity and a resulting higher bonding strength to the metal surfaces. The reduction in friction coefficients with the addition of the biofuels showed that utilisation of these blends would reduce frictional losses along the fuel line, improving the overall engine efficiency.

Impact of fuel on real diesel injector performance in field test

This work assessed the potential impact of diesel fuel complying with the EN 590 standard on real diesel injector performance in a long-term field test. Injector deposit formation has been attributed to diesel fuel instability during storage in relation to fuel injection equipment (FIE) operating conditions. These deposits can occur at different locations within FIE and impact on fuel spray characteristics, causing threats to the proper functioning of the fuel injectors. The long-term field tests were performed with two new vehicles fitted with an advanced common rail (CR) fuel injection system, meeting the requirements of Euro 5. A high quality diesel fuel meeting the requirements of the EN 590 standard was used for both vehicles. A scanning electron microscope with energy dispersive X-ray spectrometry (EDS) and an electron backscatter diffraction (EBSD) detector was used for observation and imaging of external, coking injector deposits around the nozzle fuel-flow holes and internal diesel injector deposits (IDID) in the area of the nozzle needle. An elemental analysis was performed by energy dispersive X-ray spectroscopy analysis (EDX). Evaluation of the macroscopic characteristics revealed that, despite the formation of external and internal injector deposits, there was no measurable loss of flow through the injectors. As a result, while injector deposits have adverse impacts on some injector macroscopic characteristics, they did not cause a significant deterioration of the injectors’ operating characteristic and their real performance.

Investigation of the effects of biodiesel aging on the degradation of common rail fuel injection systems

Subject of this study is the parametric investigation of the effect of biodiesel aging on the formation of deposits inside common rail Fuel Injection Equipment (FIE). The parameters investigated are key fuel properties and their degradation rate, FAME composition as well as FIE component design. Fuel degradation and deposit formation is simulated in a prototype FIE test rig. A market study was initially performed to monitor market diesel fuel quality in Europe. The sensitivity of the FIE to FAME concentration was investigated with market B7 and B20 test fuel. B20 pre-aging and fuel enhancement with anti-oxidant were studied to assess the impact of fuel degradation speed and level relatively to deposit formation. A selection of EU market B7 fuels with different fresh fuel properties and FAME composition, were comparatively evaluated on the rig as regards their impact on injection flow and pump response deterioration together with their tendency to form deposits. Test rig operation with 2 different injector designs was utilized to further investigate deposit sensitivity. Injection flow deterioration and internal deposits were affected by injector design and fuel aging speed and were found to be related to Total Acid Number. A correlation between initial B7 Rancimat IP and FIE failure due to fuel aging was identified. The methodology developed is proposed as reference test for the evaluation of current and future automotive fuels as regards their tendency to form deposits.

Effect of fuel injection parameters on combustion stability and emissions of a mineral diesel fueled partially premixed charge compression ignition (PCCI) engine

This experimental study focuses on developing new combustion concept for compression ignition (CI) engines by achieving partially homogeneous charge, leading to low temperature combustion (LTC). Partially premixed charge compression ignition (PCCI) combustion is a single-stage phenomenon, with combustion shifting towards increasingly premixed combustion phase, resulting in lower in-cylinder temperatures. PCCI leads to relatively lower emissions of oxides of nitrogen (NOx) and particulate matter (PM) simultaneously. To investigate combustion, performance and emission characteristics of the PCCI engine, experiments were performed in a mineral diesel fueled single cylinder research engine, which was equipped with flexible fuel injection equipment (FIE). Effects of fuel injection pressure (FIP) were investigated by changing the FIP from 400bar to 1000bar. Experiments were carried out by varying start of main injection (SoMI) timings (from 12° to 24° before top dead center (bTDC)), when using single pilot injection. This experimental study included detailed investigations of particulate characteristics such as particulate number-size distribution using engine exhaust particle sizer (EEPS), particulate bound trace metal analysis using inductively coupled plasma-optical emission spectrometer (ICP-OES), and soot morphology using transmission electron microscopy (TEM). PCCI combustion improved with increasing FIP (up to 700bar) due to superior fuel atomization however further increasing FIP deteriorated PCCI combustion and engine performance due to intense knocking. NOx and PM emissions were also found to be lowest at 700bar FIP. Moreover, count mean diameter (CMD) of particulate was maximum at 700bar FIP. Therefore, medium FIP (700bar) was the most suitable FIP for PCCI combustion.

Design and Performance Optimization of Off-highway Diesel Engine with Mechanical Fuel Injection Equipment for TIER-IV Emission Norms

The two cylinder diesel engines are most demanding product in Indian market for power genset and tractor applications. But major task faced by engine manufacturers all over the world is to upgrade running engine designs with minimum and cost-effective modifications to meet the next level of emission norms. This saves the precious lead time and investments. In addition uncomplicated design has to be sustained as far as possible while improving emissions. Further the basic desires of the end user in off-road market are good response, transient performance, better low end torque, best fuel efficiency and smooth operation of the engine besides best in class reliability. Additional requirements needed to sustain the market with higher power to weight ratio and increased life of the engine. Henceforth turbocharging applications for off-road diesel engines are promising solution for enhancing rated power, low speed torque, transient performance, optimized fuel efficiency and engine downsizing. A trade-off is required to match some incompatible design issues like overall dimensions, cost, emissions control and performance in order to sustain the existing design. Future diesel engine emission standards will restrict vehicle emissions, particularly nitrogen oxides. In the present work, performance improvement for 1.7L, 2 cylinder in-line naturally aspirated diesel engine with mechanical fuel injection pump for off-road application is developed to contain all needs of the market. Design up-gradation of this engine for Tier IV is made with minimal design changes by optimal combinations of fuel injection equipment. This includes proper optimization of performance with improvements in nozzle geometry, change in injector end pressure. But due to the increased fuel flow rates for improving the engine performance as well as emission reduction, there is also a requirement for increased air flow. Henceforth in this study air flow rate is simulated and discussed for selection of turbocharger and intercooler. Further elaborate design and analysis study is also done on cooled exhaust gas recirculation system for exhaust gas cooling efficiency, Diesel Oxidation catalyst, Selective Catalytic Reduction /Lean NOx Trap substrate selection for reduced pressure drop and maximum retention time for exhaust gas to achieve Tier IV norms in turbocharged intercooled two cylinder engine.

Effect of straight vegetable oil blends and biodiesel blends on wear of mechanical fuel injection equipment of a constant speed diesel engine

Vegetable oils and biodiesel have emerged as strong alternative fuels worldwide. However use of new fuels in existing engines leads to issues such as wear of vital moving components, and fuel injection equipment (FIE). It is important to ensure that new alternative fuel does not affect the FIE adversely. In this experimental study, a non-firing engine FIE simulator test rig prototype was developed and 250 h endurance test of FIE was performed with an objective to ensure the long-term compatibility and durability of biofuel blends. The components of FIE such as plunger, nozzle needle, valve, and valve holder were investigated for wear. Test fuels used in this study were Karanja blends (K20, K5), Jatropha blends (J20, J5), Biodiesel blends (B20, B5) and baseline mineral diesel in a non-firing engine FIE simulator. The compatibility of FIE with test fuels in terms of dimensional loss, weight loss and surface texture variations using optical microscopy before and after the endurance test was compared. Biodiesel blends showed relatively lower wear compared to mineral diesel however SVO blends showed no definite trend of the wear results compared to baseline mineral diesel.

A Survey of Analysis, Modeling, and Diagnostics of Diesel Fuel Injection Systems

Diesel engines are widely used due to their high reliability, high thermal efficiency, fuel availability, and low consumption. They are used to generate power, e.g., in passenger cars, ships, power plants, marine offshore platforms, and mining and construction machines. The engine is at heart of these applications, so keeping it in good working condition is vital. Recent technical and computational advances and environmental legislation have stimulated the development of more efficient and robust techniques for the diagnostics of diesel engines. The emphasis is on the diagnostics of faults under development and the causes of engine failure or reduced efficiency. Diesel engine fuel injection plays an important role in the development of the combustion in the engine cylinder. Arguably, the most influential component of the diesel engine is the fuel injection equipment; even minor faults can cause a major loss of efficiency of the combustion and an increase in engine emissions and noise. With increased sophistication (e.g., higher injection pressures) being required to meet continuously improving noise, exhaust smoke, and gaseous emission regulations, fuel injection equipment is becoming even more susceptible to failure. The injection systems have been shown to be the largest contributing factor in diesel engine failures. Extracting the health information of components in the fuel injection system is a very demanding task. Besides the very time-consuming nature of experimental investigations, direct measurements are also limited to selected observation points. Diesel engine faults normally do not occur in a short timeframe. The modeling of typical engine faults, particularly combustion related faults, in a controlled manner is thus vital for the development of diesel engine diagnostics and fault detection. Simulation models based on physical grounds can enlarge the number of studied variables and also obtain a better understanding of localized phenomena that affect the overall behavior of the system. This paper presents a survey of the analysis, modeling, and diagnostics of diesel fuel injection systems. Typical diesel fuel injection systems and their common faults are presented. The most relevant state of the art research articles on analysis and modeling of fluid injection systems as well as diagnostics techniques and measured signals describing the behavior of the system are reviewed and the results and findings are discussed. The increasing demand and effect of legislation related to diagnostics, especially on-board diagnostics (OBD), are discussed with reference to the future progress of this field.

Comprehensive system for diesel fuel cleaning

The removal of emulsified water from diesel fuels often encounters serious problems, which lead to operation failure and breakthrough of water into the fuel injection equipment. This can cause a severe damage of common rail systems. Here, a novel design of diesel filter shows significant improvements in terms of dirt holding capacity, water separation and thus the life-time of the engine.

Evaluation of the Economic Efficiency of Various Alternative Fuels in Transport

The paper deals with the evaluation of a comparative economic efficiency of various alternative and mixed fuels’ application. The method of calculating the efficiency of the use of alternative fuels on reduction the economic damage to the national economy pollution environment of the country was proposed. The results of theoretical studies confirming the feasibility of the method of calculation are given. The authors conducted the comparative analysis of the indicators of work fuel injection equipment and diesel as a whole based on change of the mean values of the effective ηе and the ηi efficiency indicator. The variants of preservation of the identity of the law of the heat flow in the cylinders of a diesel engine for work on alternative fuels and clean diesel fuel are proposed.

Fuel System Contamination Affecting Injection Equipment of Diesel Engines

This article describes selected contaminants of the fuel system which substantially affect the operation of fuel injection equipment of self-ignition engines. The authors present a simple method of identifying biological contaminants (bacteria and fungi), which can be used with no need for laboratory tests during a vessel’s voyage at sea.

Experimental investigation and hydraulic simulation of dynamic effects on diesel injection characteristics in indirect acting piezo-driven injector with bypass-circuit system

In recent years, the performance and emissions of HSDI diesel engines have been improved significantly by big progresses in the development of fuel injection equipment. This development is ongoing to fulfill stricter regulations by reducing emissions to near zero-impact levels while minimizing CO2. In most electro-hydraulic injectors for the common rail diesel fuel injection system the injection nozzle is opened and closed by the movement of an injector’s needle which is balanced by pressure at the nozzle seat and at the needle control chamber at the opposite end of the needle. In this study, spray experiment and hydraulic simulation of piezo-driven diesel injector with bypass-circuit indirectly acting as a needle’s driver have been investigated to evaluate the effect of injection control capability on spray formation processes and to predict the dynamic characteristics of the hydraulic component inside the injector by using AMESim numerical code. Results were compared with a conventional solenoid-driven injector equipped with the same micro-sac multi-hole injection nozzle. Further, a hydraulic model has been verified by comparison with the experimental results. It was found that a bypass-circuit type piezo-driven injector causes a short injection closing delay with where a rapid rate of falling slope of injection and a fast injection response and it had better injection control flexibility due to the hydraulic bypass system. Of course, the predicted simulation results in AMESim environment showed favorable agreement with experimental results.