Direct Fuel Injection Research Articles

Modified Single-Fluid Cavitation Model for Pure Diesel and Biodiesel Fuels in Direct Injection Fuel Injectors

A cavitation model has been developed for the internal two-phase flow of diesel and biodiesel fuels in fuel injectors under high injection pressure conditions. The model is based on the single-fluid mixture approach with newly derived expressions for the phase change rate and local mean effective pressure—the two key components of the model. The effects of the turbulence, compressibility, and wall roughness are accounted for in the present model and model validation is carried out by comparing the model predictions of probable cavitation regions, velocity distribution, and fuel mass flow rate with the experimental measurement available in literature. It is found that cavitation inception for biodiesel occurs at a higher injection pressure, compared to diesel, due to its higher viscosity. However, supercavitation occurs for both diesel and biodiesel at high injection pressures. The renormalization group (RNG) k-ɛ model for turbulence modeling is reasonable by comparing its performance with the realizable k-ɛ and the shear stress transport (SST) k-ω models. The effect of liquid phase compressibility becomes considerable for high injection pressures. Wall roughness is not an important factor for cavitation in fuel injectors.

Numerical Study on the Hydrogen Fueled SI Engine Combustion Optimization through a Combined Operation of DI and PFI Strategies

As the practicability of a hydrogen-fueled economy emerges, intermediate technologies would be necessary for the transition between hydrocarbon fueled internal combustion engines and hydrogen powered fuel cells. In the present study, the hydrogen engine efficiency and the load control are the two main parameters that will be improved by using the combined operation of in-cylinder direct fuel injection (DI) and port fuel injection (PFI) strategies to obtain maximum engine power outputs with acceptable efficiency equivalent to gasoline engines. Wide open throttle (WOT) operation has been used to take advantage of the associated increase in engine efficiency, in which the loads have been regulated with mixture richness (qualitative control) instead of volumetric efficiency (quantitative control). The capabilities of a 3D-CFD code have been developed and employed to simulate the whole engine physicochemical process which includes the hydrogen injection through the intake manifold (PFI) and/or the hydrogen DI in the engine compression stroke. Conditions with simulated PFI, PFI + DI and DI have been analyzed to study the effects of mixture preparation behaviors on the hydrogen ignition and its flame propagation inside the engine combustion chamber. Numerically, the CFD code has been intensively validated against experimental engine data which provided remarkable agreement in terms of in-cylinder pressure history evaluation.

Numerical investigation of the effect of injection timing under various equivalence ratios on energy and exergy terms in a direct injection SI hydrogen fueled engine

In the present article, a Computational Fluid Dynamics (CFD) method and a home-made FORTRAN code have been utilized to investigate the effects of injection timing under various equivalence ratios on the first and second laws of thermodynamics terms in a hydrogen fueled Direct Injection Spark Ignition (DISI) engine. The results show a good agreement with the experimental data. Exergy terms such as exergy transfer with work, exergy transfer with heat, exergy transfer with exhaust gas and fuel chemical exergy were computed based on principles of the second law. Also Entropy generation per cycle is calculated. Special attentions are given to recognize and quantify the irreversibility of combustion process basing on the different injection timings and equivalence ratios. The obtained results indicated that combustion irreversibilities and exhaust gas availability are more affected by varying the equivalence ratio and amount of fuel availability that transfers to environment with exhaust gases increased by increasing the equivalence ratio. Varying the equivalence ratio had different effect on the accumulated work availability reduced to fuel availability at the late and early injection strategies. Also, entropy generation reduced by retarding the hydrogen injection timing and decreasing the equivalence ratio. Changing in injection timing has its maximum effect on Φ = 0.6 equivalence ratio.

Wear, durability, and lubricating oil performance of a straight vegetable oil (Karanja) blend fueled direct injection compression ignition engine

Depletion of fossil fuel resources and resulting associated environmental degradation has motivated search for alternative transportation fuels. Blending small quantity of Karanja oil (straight vegetable oil) with mineral diesel is one of the simplest available alternatives, which can be put into application immediately. Two identical direct injection compression ignition (DICI) engines were subjected to long-term endurance test for comparing long-term durability performance of 10% blend of Karanja oil with mineral diesel (K10) vis-à-vis mineral diesel. Carbon deposits, wear of vital engine components, and effect of new fuel (Karanja oil blend) on lubricating oil were analyzed in a long-term endurance test spanning over 512 h engine operation. Wear of liner, piston, piston rings, valves, gudgeon pin, crank pin, bearings, etc., of K10 fueled engine was found to be comparable to mineral diesel fueled engine. Iron, lead, chromium, zinc metal debris in the lubricating oil were found to be lower for K10 fueled engine compared to diesel fueled engine, however, aluminum content in the lubricating oil of K10 engine was slightly higher than diesel fueled engine. Karanja oil proved to be potential partial substitute for mineral diesel in DICI engine without substantial hardware modifications.

Three-Dimensional Flamelet Simulation of Polycyclic Aromatic Hydrocarbons Formation in DI-Diesel Engines

In this study, numerical simulations for an n-heptane fueled Chaochai 6102bzl direct injection diesel engine are performed in order to predict the chemical details of the combustion process and resulting polycyclic aromatic hydrocarbons (such as benzene, naphthalene, phenanthrene and pyrene) formation. The diesel geometry and reduced kinetic mechanism of n-heptane oxidation, which includes only 86 reactions and 57 species, have been developed and incorporated into the computational fluid dynamics code, FLUENT. The diesel unsteady laminar flamelet model, turbulence model and spray model have been employed in the numerical simulations. The numerical simulation results showed that the polycyclic aromatic hydrocarbons were firstly increased with the increase of diesel crank angel and then decreased, which was mostly located at the bottom of diesel combustion chamber wall.

Direct Fuel Injection of LPG in Small Two-Stroke Engines

The commonly used carburetted two-stroke engines in developing countries have high exhaust emission and poor fuel efficiency. To meet more rigid emissions requirements, two-stroke vehicles are typically phase out in favour of four-stroke engines. The problems of ubiquitous legacy two-stroke vehicles remain unsolved by these measures and they are likely to be a major source of transport for many years to come. A number of technologies are available for solving the problems associated with two-stroke engines such as catalytic after-treatment and direct fuel injection (DI). However, these solutions are relatively high cost and have shown only slow market acceptance for applications in developing countries. Research in recent years has demonstrated that direct fuel injection is a well developed and readily deployable solution to existing two-stroke engines. Gaseous fuels such as Liquefied Petroleum Gas (LPG) are considered a promising energy source and in many countries provide fuel cost savings. LPG coupled with DI two-stroke technologies, is expected to be clean and cost effective retrofit solution for two-stroke engines. In this research project, direct injection (DI) of Liquefied Petroleum Gas (LPG) is introduced and tested on a typical two-stroke engine. Results of in cylinder combustion pressure translated to fuel mass fraction burned, engine performance and exhaust emissions are taken and compared for various injection timings from premixed (early injection) to fully direct injection mode (late injection). Results show that DI of LPG effectively reduces exhaust hydrocarbon and can substantially improve the fuel economy of two-stroke engines.

Alternative Fuel Butanol: Preliminary Investigation on Performance and Emissions of a Marine Two-Stroke Direct Fuel Injection Engine

Alternative Fuel Butanol: Preliminary Investigation on Performance and Emissions of a Marine Two-Stroke Direct Fuel Injection Engine

Comparative Investigation of Throttle-free Load Control on a 2.0 l Four Cylinder Turbocharged Gasoline Engine with Port and Direct Fuel Injection

Comparative Investigation of Throttle-free Load Control on a 2.0 l Four Cylinder Turbocharged Gasoline Engine with Port and Direct Fuel Injection

A comprehensive experimental investigation of combustion and heat release characteristics of a biodiesel (hazelnut kernel oil methyl ester) fueled direct injection compression ignition engine

In the present study, hazelnut ( Corylus avellana L.) kernel oil was transesterified with methanol using potassium hydroxide as catalyst to obtain biodiesel and a comprehensive experimental investigation of combustion (cylinder gas pressure, rate of pressure rise, ignition delay) and heat release (rate of heat release, cumulative heat release, combustion duration and center of heat release) parameters of a direct injection compression ignition engine running with biodiesel and its blends with diesel fuel was carried out. Experiment parameters included the percentage of biodiesel in the blend, engine load, injection timing, injection pressure, and compression ratio. Results showed that hazelnut kernel oil methyl ester and its blends with diesel fuel can be used in the engine without any modification and undesirable combustion and heat release characteristics were not observed. The modifications such as increasing of injection timing, compression ratio, and injection pressure provided significant improvement in combustion and heat release characteristics.

筒内燃料直接噴射を用いた混合気制御によるガソリン圧縮着火機関の運転範囲拡大に関する研究(熱工学,内燃機関,動力など)

筒内燃料直接噴射を用いた混合気制御によるガソリン圧縮着火機関の運転範囲拡大に関する研究(熱工学,内燃機関,動力など)

Numerical Investigation of Direct Fuel Injection from the Cavity Walls in 2D Supersonic Combustor

Article Numerical Investigation of Direct Fuel Injection from the Cavity Walls in 2D Supersonic Combustor was published on September 1, 2009 in the journal International Journal of Turbo & Jet-Engines (volume 26, issue 3).

DME吸気添加による水素直接噴射式ディーゼル機関に関する研究(熱工学,内燃機関,動力など)

Hydrogen has been expected as a promising alternative fuel for automotive engine applications in these days. As most suitable engine application of hydrogen, the authors propose direct injection (DI) diesel engines, which have higher thermal efficiency and lower wall heat losses due to its combustion located in the center of combustion chamber with air insulation layer. However, in the case of a diesel engine fueled with hydrogen, its higher auto-ignition temperature gives a very unstable operation. Therefore, the authors propose the methodology for raising the ambient gas temperature by adding a small quantity of Dimethyl ether (DME) to intake air. In addition, the intermediate products formed through the reactions of DME have possibilities of making auto-ignition of hydrogen jet easier and more stable. The authors have attempts to figure out the characteristics of combustion, engine performance and emission behavior in the hydrogen fueled DI diesel engine with DME intake addition. It was obtained that high performance, stable operations and low emission in engine experiments.

Experimental Study on the Combustion Characteristics and Emissions of Biodiesel Fueled Compression Ignition Engines with Premixed Dimethoxymethane

In the present study, the combustion characteristics and emissions of biodiesel fueled direct injection engines with premixed dimethoxymethane (DMM) by port injection were investigated on a single-cylinder diesel engine. The experimental results show that, for a fixed equivalence ratio of biodiesel, the ignition timing and the center point of heat release advance, while the end point of heat release delays with the introduction of premixed DMM. For a constant equivalence ratio of premixed DMM, the ignition timing delays and the end point of heat release advances with the decrease of biodiesel quantity. Furthermore, the maximum gas pressure, the mean gas temperature, and the maximum pressure rise rate increase smoothly with the increase of premixed ratio. Meanwhile, when the premixed ratio reaches to a certain value, the maximum gas pressure and pressure rising rate increase remarkably. Regarding to the regulated emissions, CO and HC emissions are much higher than that of neat biodiesel fuel and increase up to the largest levels at a certain premixed ratio. After that, both the CO and HC emissions begin to decrease substantially. Smoke opacity decreases up to 35–55% at different equivalence ratios with the premixed DMM. At last, it is very interesting to find that the NOx emission decreases about 35% under overall operating conditions with up to 20% premixed DMM.

0713 可変動弁機構を搭載したDIエンジンの低排気化技術の検討(G07-2 エンジンシステム(2),G07 エンジンシステム)

The reduction of hydrocarbon (HC) emissions at fast idle is important to improve emission performance of the Gasoline Engines. HC emissions are caused by the deposition of fuel on the combustion chamber walls. In order to decrease fuel deposition, in-cylinder air flow is enhanced by causing high intake air velocity. High intake air velocity is achieved by using intake valves with variable valve system. Intake valve lift is set low and intake valve open timing is set after of the top dead center. Incorporating this technique is found to decrease HC emissions of Direct Fuel Injection Engines thereby improving combustion stability.

The Use of Non-Parametric Regression to Investigate the Sensitivities of High-Speed Direct Injection Diesel Emissions and Fuel Consumption to Engine Parameters

A recently developed non-parametric regression (NPR) method, namely the component selection and smoothing operator (COSSO), was applied to a high-speed direct injection (HSDI) diesel engine optimization problem to analyse the complex correlations between NO x and soot emissions, and fuel consumption responses and control factors. Seven control factors were considered, including swirl ratio, fuel injection pressure, intake air boost pressure, exhaust gas recirculation (EGR), start-of-injection timings for each pulse of two-pulse injections, and the dwell between the injections. The responses are non-linearly and non-monotonically correlated to the control factors, which feature complex interactions. The models were constructed by extracting information from an undesigned and unevenly distributed data sample, whose size is small with regard to the high dimensionality of the inputs. The models perform well, as shown by cross-validations. This success reveals the potential of NPR methods as powerful analysis tools for problems of this type. Based on the current proposed well-constructed models, the importance of the control factors could be ranked according to their significance in the models, and interactions between control factors and their influence on responses could be quantitatively assessed. For example, a two-pulse injection featuring a very early first injection and a second injection well past top dead centre of compression provides excellent performance. The start-of-second-injection timing is shown to be most influential for fuel consumption and interactions between the boost pressure and the start-of-first-injection timing are important. Similarly, as expected, EGR is the most important main factor for NO x emissions, while the main and interaction effects of the second-injection timing and EGR are also very significant. All main and interaction effects were significant for soot emissions. With a complete and continuous description of response surfaces available using the method, response values at untried parameter points can also be estimated, and possibly optimal solutions can be derived without being restrained by specified search grid resolution. Moreover, the solutions can be diversified to meet various criteria. The potential of using the proposed NPR method for assisting optimal parameter search is also discussed.

A Study of the Ignition and Combustion Process in a Gasoline HCCI Engine Using Port and Direct Fuel Injection(HCCI, Combustion Processes I)

A Study of the Ignition and Combustion Process in a Gasoline HCCI Engine Using Port and Direct Fuel Injection(HCCI, Combustion Processes I)

914 シリンダ内燃料直接噴射 2 サイクル機関の研究

914 シリンダ内燃料直接噴射 2 サイクル機関の研究

360 ガス燃料筒内噴射 2 サイクル機関における燃焼過程の数値解析

360 ガス燃料筒内噴射 2 サイクル機関における燃焼過程の数値解析

605 2ストロ-クエアアシスト式直噴船外機の開発(O.S.6 エンジンシステムの性能向上と環境対応)(オーガナイズドセッション6 : エンジンシステムの性能向上と環境対応)

605 2ストロ-クエアアシスト式直噴船外機の開発(O.S.6 エンジンシステムの性能向上と環境対応)(オーガナイズドセッション6 : エンジンシステムの性能向上と環境対応)

319 直接噴霧式管状火炎バーナの燃焼特性(燃焼)

319 直接噴霧式管状火炎バーナの燃焼特性(燃焼)