Injection System Of Diesel Engine Research Articles

Dynamic performances analysis and optimization of novel high-speed electromagnetic actuator for electronic fuel injection system of diesel engine

High-speed electromagnetic actuator (HEA) is the key component of Electronic fuel injection system (EFIS) of diesel engine, its dynamic performances have a significant impact on the control accuracy and flexible control law of fuel injection. In order to obtain the higher dynamic response speed, lower power consumption, higher safety and reliability, a novel HEA with permanent magnet (NPMHEA) was proposed based on the principle of parallel magnetic circuit in this paper. Then the simulation models of HEA coupling of magnetic field, electric circuit and mechanical motion were developed by the method of time-stepping finite element, and their precisions were verified by experiment. By the comparative analysis, influence rules of key parameters on the dynamic performances of HEA have been established. In addition, the multi-objective optimization of NPMHEA based on response surface methodology and Genetic algorithm (GA) was carried out and the Pareto optimal solution set was obtained. It is concluded that there are contradictions between objectives for the Pareto optimal solutions; considering the whole performances, the optimal solution is determined for which the peak current, the peak pulse and the hold current reduce by 20.5 %, 7.8 % and 43.9 %, respectively, and the actuation response speed quickens by 11.9 %, significantly reducing the power consumption and coil loss and improving the dynamic response speed of HEA. It decisively provides certain theoretical guidance for the design and optimization of HEA.

Lubrication and frictional analysis of cam–roller follower mechanisms

In this work, a full numerical solution to the cam–roller follower-lubricated contact is provided. The general framework of this model is based on a model describing the kinematics, a finite length line contact isothermal-EHL model for the cam–roller contact and a semi-analytical lubrication model for the roller–pin bearing. These models are interlinked via an improved roller–pin friction model. For the numerical study, a cam–roller follower pair, as part of the fuel injection system in Diesel engines, was analyzed. The results, including the evolution of power losses, minimum film thickness and maximum pressures, are compared with analytical solutions corresponding to infinite line contact models. The main findings of this work are that for accurate prediction of crucial performance indicators such as minimum film thickness, maximum pressure and power losses a finite length line contact analysis is necessary due to non-typical EHL characteristics of the pressure and film thickness distributions. Furthermore, due to the high contact forces associated with cam–roller pairs as part of fuel injection units, rolling friction is the dominant power loss contributor as roller slippage appears to be negligible. Finally, the influence of the different roller axial surface profiles on minimum film thickness, maximum pressure and power loss is shown to be significant. In fact, due to larger contact area, the maximum pressure can be reduced and the minimum film thickness can be increased significantly, however, at the cost of higher power losses.

A computational parametric analysis of cavitating flows in injector nozzles

The fuel injection system in diesel engines has crucial influence on the engine’s combustion process and emission formation. Cavitation in injector nozzles plays a critical role in primary spray break-up and atomization. Understanding the phenomenon of cavitation is hence important for accurate design of the injection process. This work presents a computational study of the characteristics of cavitating flows in the two-dimensional (2D) injector nozzle. The computations are performed by employing the multi-phase mixture approach with the k–ε realizable turbulence model and Schnerr–Sauer cavitation model. The results demonstrate the capability of the modeling framework to successfully predict the following experimentally observed cavitation regimes: no cavitation, developing cavitation, and super cavitation. A parametric study of the effects of the cavitation number σ and the Reynolds number Re verifies the experimental finding that cavitation strongly depends on σ, while the effect of Re is not large.

Evaluation of the biodiesel fuels lubricity using vibration signals and multiresolution analysis

The vibration is an important feature associated with metallic contact during operation of the injection system of diesel engines, also its analysis constitutes a tool to evaluate the lubricity indirectly. In this sense, this work uses multiresolution analysis to characterize vibration signals, improving lubricity evaluation. The experimental setup consisted of the lubricity analysis of different fuels using HFRR equipment where friction coefficient was monitored during the test as well as vibration signals. After that, Discrete Wavelet Transform generated time-scale representation of the vibration signals. This analysis provides complementary information about lubrication, in real time, and it can be associated with wear scar diameter (WSD). The results demonstrated the feasibility of this approach to evaluate fuels lubricity in a dynamic way.

Emissions From a Diesel Engine Operating in a Dual-Fuel Mode Using Port-Fuel Injection of Heated Hydrous Ethanol

Aftermarket dual-fuel injection systems in diesel engines using hydrous ethanol as secondary fuel have been developed as a means to lower emissions from older diesel-powered equipment. However, our previous work has shown that the emissions benefits of currently available aftermarket intake fumigation injection systems can be inconsistent with manufacturer claims. Our current study evaluates a newly developed aftermarket dual-fuel system that incorporates a fuel heating system and port fuel injection (PFI). This paper describes an experimental investigation of engine-out emissions from a John Deere 4045HF475 Tier 2 engine with port injection of 180 proof (90% ethanol by volume) hydrous ethanol. The engine was retrofitted with a custom fuel heat exchanger to heat the hydrous ethanol to a range of 46–79 °C for helping to improve fuel vaporization in the intake port. PFI duration was controlled using engine speed and throttle position as inputs to achieve a desired fumigant energy fraction (FEF), defined as the amount of energy provided by the hydrous ethanol based on lower heating value (LHV) over the total fuel energy provided to the engine. Data was collected over a range of FEF with direct injected diesel for eight operating modes comparing heated versus unheated hydrous ethanol. Results of the study indicate that as FEF increases, NO emissions decrease, while NO2, CO, THC, and unburned ethanol emissions increase. In addition, it was found that preheating the ethanol using engine coolant prior to injection has little benefit on engine-out emissions. The work shows that the implemented aftermarket dual-fuel PFI system can achieve FEF rates up to 37% at low engine load while yielding modest benefits in emissions.

Tribological and emission characteristics of indirect ignition diesel engine fuelled with waste edible oil

Purpose Energy is the prime mover of economic growth and is vital to the sustenance of a modern economy. Future economic growth depends heavily on the long-term availability of energy from sources that are affordable, accessible and environmentally friendly. Regulating the sulfur content in diesel fuel is expected to reduce the lubricity of these fuels, which may result in increased wear and damage of fuel injection systems in diesel engines. Design/methodology/approach The tribological properties of the biodiesels as additive in pure petro-diesel are studied by ball-on-ring wear tester to find optimal concentration, and the mechanism of the reduction of wear and friction will be investigated by optical microscopy. Findings Studies have shown that low concentrations of biodiesel blends are more effective as lubricants because of their superior polarity. Using biodiesel as a fuel additive in a pure petroleum diesel fuel improves engine performance and exhaust emissions. The high biodegradability and superior lubricating property of biodiesel when used in compression ignition engines renders it an excellent fuel. Originality/value This detailed experimental investigation confirms that biodiesel can substitute mineral diesel without any modification in the engine. The use of biofuels as diesel engine fuels can play a vital role in helping the developed and developing countries to reduce the environmental impact of fossil fuels.

Effect of injector parameters on the injection quantity of common rail injection system for diesel engines

In this paper, the bond graph model of common rail injector was proposed in consideration of the effects of variable liquid capacitance and fuel physical property on the injection characteristics of the injector. State equations were derived based on the model, which were numerically solved by programming in Matlab. Comparisons between the simulation results and the experimental data show that the numerical model can effectively predict the injection quantity of the system. Effect of variation of delivery chamber diameter, needle seat semi-angle, needle cone semi-angle, ball valve seat semi-angle, nozzle hole diameter, inlet orifice diameter and outlet orifice diameter on fuel injection quantity had been analyzed. The influence rules of various parameters on the fuel injection quantity had been established. The experiments were conducted using face centered central composite design. A second order polynomial response surface model had been developed for predicting fuel injection quantity, as a function of the independent variables. Analysis of variation was used to determine the significance interactions which primarily affect the fuel injection quantity. It had been concluded that six interaction factors including delivery chamber diameter with nozzle hole diameter, needle seat semi-angle with needle cone semi-angle, needle seat semi-angle with nozzle hole diameter, needle cone semi-angle with nozzle hole diameter, nozzle hole diameter with inlet orifice diameter, and nozzle hole diameter with outlet orifice diameter have significant effect on the fuel injection quantity of the system.

Hydraulic Performance Comparison Between the Newly Designed Common Feeding and Standard Common Rail Injection Systems for Diesel Engines

A new-generation common feeding (CF) fuel injection system without rail has been compared with the standard common rail (CR) apparatus for diesel engine passenger cars. The high-pressure pump in the CF apparatus is connected directly to the injectors, and a volume of about 2.5 cm3 is integrated at the pump delivery. Experimental tests on solenoid injectors have been carried out for the CF and CR apparatus at a hydraulic test rig. The dependence of the injected volumes and total injector leakages on the energizing time (ET) of the two systems has been investigated for different rail pressure levels. Furthermore, the measured injected flow-rates of the CF and CR systems have been compared for single and pilot–main injection events. In general, the injection performance of the two systems is very similar, even though the differences occur in the high-pressure transients. The dynamics of the pressure waves changes because the high-pressure hydraulic layouts of the two systems are different, and the propagation and reflection of the rarefaction waves, triggered by the injection events, occur in different ways. A previously developed one-dimensional (1D) code for the CF high-pressure layout has been further validated by means of a comparison with the experimental data. The effects of either a calibrated orifice installed at the pump delivery or an injector-integrated Minirail on the CF performance have been investigated by means of the model. Numerical parametrical tests have also been conducted on the pump-to-injector pipe length. The additional orifices that can be installed in the high-pressure circuit of the CF are effective, provided their diameter is smaller than the diameter of any other orifice inserted in the injector. Furthermore, the presence of a Minirail within the injector has an impact on the injected flow-rates of small injections, such as pilot, pre, after, and post, and also induces a reduction in the energy stored in the pressure waves. Another relevant active damping strategy of the pressure waves for the CF involves shortening the pump-to-injector pipe as much as possible. Finally, the fluid dynamical transients within the solenoid injector have been discussed for the CF and CR systems. The numerical time distributions of the main variables within the injector are shown to be independent of the presence of the rail in the layout.

Результаты испытаний аккумуляторных топливных систем дизелей с давлением впрыскивания до 300 МПа

Результаты испытаний аккумуляторных топливных систем дизелей с давлением впрыскивания до 300 МПа

Reliability analysis on high-pressure fuel pipe of diesel engine

High-pressure fuel pipe is an important component of the fuel injection system of diesel engine, it suffer complex loading from engine. The fatigue life of fuel pipe has great impact on reliability of engine. In this study, the fluid-solid coupling model which considers the action of fuel is established. Analysis on the effect of fuel’s pressure oscillation on the mode is carried out. Through the simulation comparisons, the mode frequency and mode shape of each model are all analysed. Base on the fluid-solid coupling model, frequency response analysis is done to study the reliability of high-pressure fuel pipe. The results show that the pressure oscillation of fuel has important influence on the mode frequency. The maximum Stress Tensor and Vibration Velocity appeared at the position of first order mode frequency. It offers the guidance for the design and analysis of High-pressure fuel pipe.

Effects of concentration and temperature on tribological properties of biodiesel

For tribologists, continuing challenges in engine design include reduced emissions and increased operating temperatures. Regulating the sulfur content in diesel fuel is expected to reduce the lubricity of these fuels, which may result in increased wear and damage of fuel injection systems in diesel engines. However, the use of biodiesel improves lubricity and cetane number requirements, particularly in ultra-low sulfur petro-diesel. In this study, the effect of temperature on the tribological properties of palm biodiesel was investigated using a wear machine. Palm biodiesel was used as a lubricating additive to petro-diesel at six concentrations of 2%, 5%, 10%, 20%, 50%, and 100%, and these biodiesel blends were named as B2, B5, B10, B20, B50, and B100, respectively. The tribological experiments were performed using the ball-on-ring method. Tests were conducted at 30°C, 60°C, 90°C, and 120°C, under a normal load of 50 N for 2 h and at a speed of 500 r/min. The wear scar diameter and the worn surface of tribopairs were studied and analyzed. According to the wear experimental results, the addition of a small amount of palm biodiesel to petroleum diesel can bring about a considerable reduction in the wear and friction under boundary lubrication. Results show that friction and wear increase with increasing temperature.

Optimizing Jatropha biodiesohol composition for a suitable kinematic viscosity by a phase diagram and mixture design

Jatropha biodiesohol (JBH) is an alternative microemulsion-based fuel that promotes the use of non-edible vegetable oils and bioethanol, replacing fossil fuel consumption. Unprocessed vegetable oil is more eco-friendly than transesterified biodiesel, which consumes a substantial amount of chemicals, energy, and water. However, this unprocessed vegetable oil has a limitation on the injection system of diesel engines because of its high viscosity. Microemulsification technique is introduced to alleviate this problem by adding an alcohol ethoxylate surfactant (LS) and bioethanol. The ethylene oxide group (at LS1, LS3 and LS7) of the surfactant, the ratio of the ethanol–surfactant (E/S ratio), and the ethanol and surfactant content (E/S content) were studied to improve the miscibility of Jatropha biodiesohol. To screen for the optimum product, those factors forming a water in oil microemulsion with transparent, clear, and homogeneous JBH were screened for in phase behavior experiments and kinematic viscosity experiments. LS1 is the most appropriate for solubilizing all components because of its low HLB (hydrophilic–lipophilic balance). The increase E/S ratio and E/S content enhance the reduction of the kinematic viscosity. A mixture design was applied to optimize the composition of each component to predict the desired kinematic viscosity. Compared with the other models, the results indicate that the full cubic model of a {3,3} simplex lattice model with three interior points and a centroid in the mixture design (providing) displayed the best fit when screening and optimizing the kinematic viscosity with R2=0.998 and MAPE=5.031%.

Wear Characteristic of Stainless Steel 304 Sliding against Cast Iron under Lubrication Environment of Palm Biodiesel Fuel

The used of palm-biodiesel fuel in automotive industry is increasing rapidly nowadays. Among the reasons are high efficiency modern fuel injection system of diesel engines and the shortage of petroleum diesel fuel from fossil resources. Among the parts affected by the fuel switch are fuel pumps components, including the fuel injection needle. Those components, working under the lubrication environment of the fuel, have to be prevented from excessive wear to maintain their high performances. This paper discussed the wear characteristics of stainless steel 304 sliding against cast iron under the lubrication environment of palm-biodiesel fuel with the concentration of 7.5% palm methyl ester in the petroleum diesel fuel. The material pair is chosen because of their widely used as mechanical components. The tests were conducted using a ball on disk tribometer. The results show that wear of the stainless steel ball is smaller in the environment with the presence of palm methyl ester content in the diesel fuel compared to that in the environment without the presence of the palm methyl ester content. The results suggested that palm-biodiesel fuel is favorable in decreasing the wear of the material.

커먼레일 분사 시스템에서 DME-LPG 혼합연료의 분무거동에 관한 연구

Abstract This study is to investigate the spray behavior of DME-LPG blended fuels in common rail injection system for die-sel engines. The visualization experiment was performed to analyze the macroscopic spray behavior of test fuels. Inaddition, the experiment using BOS(Background Oriented Schlieren) method is performed to compare liquid phase andgas phase. The test fuels are injected in high pressure chamber. The ambient pressure of high pressure chamber wasformed by nitrogen gas. Spray tip penetration, spray cone angle and spray area were measured using high speed cam-era. SMD(Sauter Mean Diameter) and spray particle velocity were measured using the PDPA(Phase Doppler ParticleAnalyzer) system to analyze the microscopic properties of test fuels. The results of this experiment showed that spraytip penetration, spray cone angle and spray area of DME-LPG fuels are similar to those of DME fuel. When comparedto results of experiment using BOS, significant differences of spray tip penetrations, spray cone angle and spray areaare showed because of gas phase. The results of experiment using BOS method showed higher values. SMD of DME-LPG blended fuels is smaller than that of DME fuel. Velocity of DME-LPG blended fuels is faster than that of DMEfuel.

High speed direct injection diesel engines

The basic sciences in diesel engine combustion are considered; direct and indirect diesel engine injection systems are described; and recent developments in the application of high speed engines to light vehicles are reviewed. The latter are discussed with respect to Ford's development aims of confirming the capability of a high speed direct injection system to achieve satisfactory power, engine speed, economy and emissions control; of developing the necessary high pressure fuel injection pumps; and demonstrating a feasible engine that can be mass produced.

Theoretical analysis and mathematical modelling of a high-pressure pump in the common rail injection system for diesel engines

In this paper, a study on the performance of a high-pressure pump of the common rail fuel injection system is presented. The mathematical models established include: (i) the fluid model for the pump chamber and rail which takes the structural deformation and interface leakage into consideration; (ii) the nonisothermal fluid–structure interaction model for the leakage at the piston/cylinder interface; and (iii) the unified model for the physical properties of the fuel such as dynamic viscosity, density and isobaric specific heat capacity versus pressure and temperature relationships. The factors leading to the loss of the pump volumetric efficiency during the four phases of the pump working cycle are theoretically analysed. Both differential and iterative methods are applied in the numerical solution of the model. The leakage model was validated against the measured leakage rates, and showed satisfactory results. A parametric study is carried out to analyze the effects the piston diameter has on the establishment process of the chamber pressure, the piston/cylinder interface leakage and the compression stroke. Results show that the impacts of the leakage, the compression stroke and the suction loss on the volumetric efficiency loss of the pump all increase with the nominal rail pressure.

Nonlinear Modeling and Analysis of Pressure Wave inside CEUP Fuel Pipeline

Operating conditions dependent large pressure variations are one of the working characteristics of combination electronic unit pump (CEUP) fuel injection system for diesel engines. We propose a precise and accurate nonlinear numerical model of pressure inside HP fuel pipeline of CEUP using wave equation (WE) including both viscous and frequency dependent frictions. We have proved that developed hyperbolic approximation gives more realistic description of pressure wave as compared to classical viscous damped wave equation. Frictional effects of various frequencies on pressure wave have been averaged out across valid frequencies to represent the combined effect of all frequencies on pressure wave. Dynamic variations of key fuel properties including density, acoustic wave speed, and bulk modulus with varying pressures have also been incorporated. Based on developed model we present analysis on effect of fuel pipeline length on pressure wave propagation and variation of key fuel properties with both conventional diesel and alternate fuel rapeseed methyl ester (RME) for CEUP pipeline.

Cavitation in Injector Nozzle Holes – A Parametric Study

The fuel injection system in diesel engines has a consequential effect on the fuel consumption, combustion process and formation of emissions. Cavitation and turbulence inside a diesel injector play a critical role in primary spray breakup and development processes. Thus understanding the phenomenon of cavitation is significant in capturing the injection process with accuracy. In this study, the cavitating flow inside an injector nozzle hole was numerically investigated. The two-phase mixture model by Schnerr and Sauer (2001) was adopted along with k-ε turbulence model and Fluent CFD package was used to solve the governing equations numerically. The validation of the model was done by comparing the numerical results with the experimental results of Winklhofer et al. (2001) for U-throttle geometry and a good agreement was found. In this paper, a detailed parametric study on the effects of injection pressure, transient analysis for diesel and SME (Soy Methyl Esther) bio-diesel and different geometries on cavitation phenomenon inside the injector nozzle hole was done. The results show that the bio-diesel inhibits the cavitation phenomenon compared to diesel fuel, and positive Kfactor nozzles have higher mass flow rate and higher exit velocity.

飞秒激光高精细加工柴油机喷油嘴倒锥孔法

Femtosecond laser processing has litle-thermal effects,high precision,and is not particular about materials.Aiming at the machining requirement for nozzle′s spray holes,as a key part of the high pressure common rail injection system for diesel engine,a femtosecond laser processing apparatus with three-wedge scanning system was designed for technical research of taper holes′machining.Then tests of the taper holes′physical dimensions and the flow rate of the fuel jet nozzles were carried out with three coordinates measuring machine(measurement accuracy 1.2μm)and high-pressure liquid flow test bench for the injector(measurement accuracy ±0.1%).The experimental results show that the designed apparatus can machine nozzles,and the performance is able to meet the application requirement of Euro V emission regulations.The technique has important significance for improving the level of automobile industry and domestic emission standard of diesel engined car.

Model based tuning of a variable-speed governor for a distributor fuel-injection pump

Rather obsolete, mechanical governors are still used in an enormous number of existing and even some new diesel engine injection systems. Change of a governor characteristic and adapting to a specific engine application is possible through adjustments of governor's elements. In order to achieve fast and accurate evaluation of adjustable parameters, mathematical model of a governor is introduced. This paper deals with the impact of adjustable parameters on static and dynamic characteristics of the mechanical variable-speed governor in DPA distributor type fuel injection pump. Dynamic testing of a closed loop Diesel engine - governor - injection system is conducted within comprehensive 1D multidomain simulation environment.