scholarly journals Analysis of the Influence of Diesel Spray Injection on the Ignition and Soot Formation in Multiple Injection Strategy

Energies ◽  
2020 ◽  
Vol 13 (13) ◽  
pp. 3505
Author(s):  
Raul Payri ◽  
José M. García-Oliver ◽  
Victor Mendoza ◽  
Alberto Viera
Keyword(s):  
Ignition Delay ◽  
Soot Formation ◽  
Single Injection ◽  
Engine Performance ◽  
Injection System ◽  
Multiple Injection ◽  
Multiple Injection Strategy ◽  
Test Points ◽  
Start Of Combustion ◽  
Injection Strategies

Multiple injection strategies have increased their capabilities along with the evolution of injection system technologies up to the point that nowadays it is possible to inject eight different pulses, permitting to improve the engine performance, and consequently, emissions. The present work was realized for two simplified strategies: a pilot-main and a main-post, in order to analyze the influence of an auxiliary pulse on the main and otherwise, in reactive conditions for two pilot/post quantities and four hydraulic dwell times. The study was carried out by employing two optical techniques: diffused back-illumination with flame bandpass chemiluminescence for measuring soot, represented by soot-maps distribution, and single-pass schlieren for ignition delay (ID). Furthermore, a novel methodology for decoupling the start of combustion (SOC) of the second pulse was developed and successfully validated. From the ignition delay results, it was found for all test points that the pilot injection enhanced conditions, which promote a faster ignition of the main pulse, also at higher chamber temperatures, all conditions presented a separate combustion event for each injection. In emission terms, soot increased in the pilot-main strategies compared to its single injection case, as well as, in conditions that promote faster-premixed combustion.

Optical Investigation of HCCI Two-Stage Ignition Using Multiple Injection of Synthetic Fuels

2005 ◽  
Author(s):  
Thaddaeus Delebinski ◽  
Peter Eckert ◽  
Guenter P. Merker
Keyword(s):  
Cfd Simulation ◽  
Hole Injection ◽  
Injection System ◽  
Optical Investigation ◽  
Multiple Injection ◽  
Synthetic Fuels ◽  
Mixture Formation ◽  
Two Stage ◽  
Injection Strategy ◽  
Multiple Injection Strategy

Different synthetic fuels have been investigated within a variety of optical experiments at a rapid compression machine using diverse optical set-ups. The experiments have been carried out to determine the fuel requirements for good homogenisation and a controlled ignition and heat release for HCCI combustion. A directly actuated piezo injection system, which allows a flexible multiple injection strategy has been used to inject the fuel at different times during the compression stroke. Mie-scatter and Schlieren optics have been applied to investigate the different behaviour of the synthetic fuels concerning evaporation and mixture formation. The auto ignition behaviour of the different fuels has been investigated using an intensified relay optics and combustion chamber probes utilising the two-colour-method and a photo multiplier analysis systems. A multiple injection strategy and a 13 hole injection nozzle for HCCI operation mode with diesel-like fuels have been designed and optimised using CFD simulation prior to the experimental work. The experimental results using synthetic fuels will then be used to verify advanced 3D CFD models for multi component fuels and their behaviour concerning mixture formation and HCCI two-stage ignition.

scholarly journals 2D CFD Simulation of Water Injection Strategies in a Large Marine Engine

2019 ◽  
Vol 7 (9) ◽  
pp. 296 ◽  
Author(s):  
Senčić ◽  
Mrzljak ◽  
Blecich ◽  
Bonefačić
Keyword(s):  
Cfd Simulation ◽  
Soot Formation ◽  
Direct Injection ◽  
Water Injection ◽  
Engine Performance ◽  
Nox Emissions ◽  
Water Emulsion ◽  
Marine Engine ◽  
Soot Emissions ◽  
Injection Strategies

A two-dimensional computational fluid dynamics (2D CFD) simulation of a low-speed two-stroke marine engine simulation was performed in order to investigate the performance of 2D meshes that allow the use of more complex chemical schemes and pollutant formation analysis. Various mesh density simulations were compared with a 3D mesh simulation and with the experimentally obtained cylinder pressure. A heavy fuel model and a soot model were implemented in the software. Finally, the influences of three water injection strategies were simulated and evaluated in order to investigate the capability of the model and the influence of water injection on NOx formation, soot formation, and engine performance. We conclude that the direct water injection strategy reduces NOx emissions without adversely affecting the engine performance or soot emissions. The other two strategies—Intake air humidification and direct injection of fuel–water emulsion—reduced NOx emissions but at the cost of higher soot emissions or reduced engine performance.

scholarly journals Influence of narrow fuel spray angle and split injection strategies on combustion efficiency and engine performance in a common rail direct injection diesel engine

2016 ◽  
Vol 9 (1) ◽  
pp. 71-81 ◽  
Author(s):  
Raouf Mobasheri
Keyword(s):  
Diesel Engine ◽  
Direct Injection ◽  
Engine Performance ◽  
Spray Angle ◽  
Fuel Spray ◽  
Multiple Injection ◽  
Split Injection ◽  
Direct Injection Diesel Engine ◽  
Piston Bowl ◽  
Injection Strategies

Direct injection diesel engines have been widely used in transportation and stationary power systems because of their inherent high thermal efficiency. On the other hand, emission regulations such as NOx and particulates have become more stringent from the standpoint of preserving the environment in recent years. In this study, previous results of multiple injection strategies have been further investigated to analyze the effects of narrow fuel spray angle on optimum multiple injection schemes in a heavy duty common rail direct injection diesel engine. An advanced computational fluid dynamics simulation has been carried out on a Caterpillar 3401 diesel engine for a conventional part load condition in 1600 r/min at two exhaust gas recirculation rates. A good agreement of calculated and measured in-cylinder pressure, heat release rate and pollutant formation trends was obtained under various operating points. Three different included spray angles have been studied in comparison with the traditional spray injection angle. The results show that spray targeting is very effective for controlling the in-cylinder mixture distributions especially when it accompanied with various injection strategies. It was found that the optimum engine performance for simultaneous reduction of soot and NOx emissions was achieved with 105° included spray angle along with an optimized split injection strategy. The results show, in this case, the fuel spray impinges at the edge of the piston bowl and a counterclockwise flow motion is generated that pushes mixture toward the center of the piston bowl.

Effect of split injection on mixture formation and combustion processes of diesel spray injected into two-dimensional piston cavity

2017 ◽  
Vol 232 (8) ◽  
pp. 1121-1136 ◽  
Author(s):  
Kang Yang ◽  
Hirotaka Yamakawa ◽  
Keiya Nishida ◽  
Youichi Ogata ◽  
Yusuke Nishioka
Keyword(s):  
Soot Formation ◽  
Single Injection ◽  
Injection Pressure ◽  
Diesel Spray ◽  
Two Dimensional ◽  
Mixture Formation ◽  
Split Injection ◽  
Main Injection ◽  
Combustion Processes ◽  
Injection Strategies

The objective of this study is to obtain an enhanced understanding of the effect of split injection on mixture formation and combustion processes of diesel spray. A two-dimensional (2D) piston cavity of the same shape as that used in a small-bore diesel engine was employed to form the impinging spray flame. The fuel was injected into a high pressure, high temperature constant volume vessel through a single-hole nozzle with a hole diameter of 0.11 mm. The injection process comprised a pre-injection followed by the main injection. The main injection was carried out either as a single injection of injection pressure 100 MPa (Pre+S100), or by two types of split injection of injection pressure 160 MPa. The latter two types were defined by mass fraction ratios 1:1 and 3:1 (Pre+D160_1-1, Pre+D160_3-1). In order to observe the spray mixture formation process, the tracer laser absorption scattering (LAS) techique was adopted. Tracer LAS fuel with 97.5 vol% of n-tridecane and 2.5 vol% of 1-methylnaphthalene (α-MN) was employed. The spatial distributions of the vapor and liquid phases and the spray mixture formation characteristics in the 2D piston cavity for the three injection strategies were investigated. The diesel spray combustion and soot formation processes were studied using a high-speed video camera. The flame structure and soot formation process were examined using two-color pyrometry. The experimental results revealed that the split-injection vapor distribution was significantly more homogeneous than that of the single injection. The main injection fuel caught up with the pre-injection fuel and provided the spray tip with substantial additional momentum, enabling it to advance further. A high soot concentration and low temperatures appeared near the cavity wall region under the three injection strategies. The soot reduction rate for split injection was higher than that for single injection. The second main injection caught up with the previous injection’s flame, which deteriorated the combustion and resulted in higher soot generation. The effect of split injection on the process of soot evolution finished at the same time as that of single injection.

A Review of Ignition Delay and Combustion Characteristics of Biodiesel Fueled Diesel Engine

2013 ◽  
Vol 390 ◽  
pp. 333-337 ◽  
Author(s):  
Mehran Qate ◽  
Majid Pourabdian ◽  
Alireza Javareshkian ◽  
Ali Farzbod
Keyword(s):  
Diesel Engine ◽  
Ignition Delay ◽  
Alternative Energy ◽  
Cetane Number ◽  
Energy Resource ◽  
Engine Performance ◽  
Calorific Value ◽  
Review Article ◽  
Combustion Characteristics ◽  
Start Of Combustion

Increasing rate of demanding biodiesel as alternative energy resource, persuade researchers to investigate engine performance of biodiesel-fueled engines, which are highly influenced by ignition delay (ID) and combustion characteristics of such a fuel. This review article introduces a literature review on ignition delay (ID) and combustion characteristics of diesel engine fueled with biodiesel. Slightly difference between combustion characteristics of bio fueled engine and petroleum diesel one recognized as result of carried out investigations. Early start of combustion (SOC) and shorter ID of biodiesel comparing to diesel is reported by most of investigations. Lower compressibility, higher Cetane Number (CN) and fatty acid composition of biodiesel have been recognized as the principle elements of early SOC and shorter ID. It is also revealed that heat release rate (HRR) of biodiesel comparing to diesel is slightly lower because of lower calorific value, shorter ID and higher viscosity.

scholarly journals Mitigation of Emissions through Injection Strategies for C I Engine

2021 ◽  
Author(s):  
Jayashri N. Nair
Keyword(s):  
Fuel Injection ◽  
Exhaust Gas Recirculation ◽  
Nox Emissions ◽  
Brake Specific Fuel Consumption ◽  
Multiple Injection ◽  
Multiple Injection Strategy ◽  
Gas Recirculation ◽  
Dwell Period ◽  
Number Of Injections ◽  
Injection Strategies

Fuel conversion efficiency is high with diesel engines compared to petrol engines. However high emissions from diesel is a matter of concern and its mitigation paves way for scope of research. Exhaust gas recirculation is one of the method widely accepted to curb NOx emissions. Recently, split or multiple-injection strategy has been explored by researchers to precisely control the fuel injected per cycle and also to mitigate emissions. Present work reflects technical review of effect of injection strategies on performance, emissions and combustion on C.I. engine with diesel and biodiesel as fuel. Injection strategies like duration of injection, number of injections, the dwell period between two injections, quantity of injection, and multiple injections are analyzed for their influence on engine output and brake specific fuel consumption. Also their effect on emissions especially soot and NOx emission are reviewed. First the effect of injection strategies with diesel fuel is discussed followed by biodiesel.

Fuel-Line Stationary Waves and Variability in CI Combustion During Complex Injection Strategies

2010 ◽  
Author(s):  
A. D. Michailidis ◽  
R. K. Stobart ◽  
G. P. McTaggart-Cowan
Keyword(s):  
Fuel Injection ◽  
Stationary Wave ◽  
Potential Method ◽  
Combustion Stability ◽  
Injection System ◽  
Stationary Waves ◽  
Main Injection ◽  
Total Fuel Consumption ◽  
Start Of Combustion ◽  
Injection Strategies

This study investigated the effects of increased injection regime complexity on injector and combustion stability in a naturally aspirated single cylinder diesel engine equipped with a common rail fuel injection system and an instrumented injector. The injection regimes investigated included a single injection, a main injection with a pilot, and a split-main with a pilot. Injector performance was found to be very stable over all injection regimes and did not contribute to variations in combustion stability. Cylinder pressure variation during the initiation of combustion was identified as a potential method of identifying the start of combustion phasing and compared to current methods. Three series of tests were conducted at various speeds and injection pressures to demonstrate the influence of multi-pulse injection phasing on combustion stability and total fuel consumption. These results demonstrate that the presence of a stationary wave in the high-pressure fuel line, induced by an early injection, can dramatically affect the amount of fuel injected in subsequent injections within the same cycle.

Experimental Study of Injection and Combustion in a Diesel Engine for Heavy Quadricycle Use

2012 ◽  
Author(s):  
Ezio Mancaruso ◽  
Bianca M. Vaglieco ◽  
Luigi Allocca ◽  
Alessandro Montanaro ◽  
Luigi Arnone
Keyword(s):  
Soot Formation ◽  
Injection System ◽  
Spatial Density ◽  
Experimental Investigations ◽  
Maximum Pressure ◽  
Common Rail Injection System ◽  
The Third ◽  
Common Rail Injection ◽  
Density Analysis ◽  
Injection Strategies

An experimental investigation has been carried out on a diesel 1000 cc, two-valve, three-cylinder, engine for heavy quadricycle and off-road applications. The engine was equipped with a unit-pump common rail injection system, automotive derived, with maximum pressure 140 MPa and ECU able to manage multinjection strategies in Euro 4 target for the foreseen applications. Experimental investigations on the fuel spray have been carried out in an optically accessible vessel at engine gas density. Spatial and temporal spray behavior has been studied by image processing of the evolving jet pictures. Spray tip penetrations, cone angles and fuel spatial density analysis have been extracted and correlated to the injection and engine parameters. On the other side, visible flame propagation and soot formation process have been evaluated by digital imaging at high spatial and temporal resolution using a quartz window of the third cylinder obtained modifying the engine head. Strategies consisting of two injections per cycle, pilot and main, and typical of real engine working conditions have been investigated in the pressure range 43–116 MPa both in terms of injection rates and injected fuel dispersion. The effects of different injection strategies on soot formation and exhaust emissions have been evaluated.

An Investigation of Multi-Injection Strategies for a Dual-Fuel Pilot Diesel Ignition Engine at Low Load

2016 ◽  
Vol 139 (1) ◽  
Author(s):  
Amin Yousefi ◽  
Madjid Birouk
Keyword(s):  
Single Injection ◽  
Fluid Dynamic ◽  
Engine Performance ◽  
Dual Fuel ◽  
Injection Timing ◽  
Double Injection ◽  
Indicated Mean Effective Pressure ◽  
Soot Emissions ◽  
Injection Pulse ◽  
Injection Strategies

A multidimensional computational fluid dynamic (CFD) model was developed in order to explore the combined effect of injection timing and fuels quantity ratio of different injection strategies on the combustion performance and emissions characteristics of a dual-fuel indirect injection (IDI) engine with a pilot diesel ignition. The total mass of pilot diesel and premixed natural gas equivalence ratio were kept constant while various injection strategies (single, double, and triple) were investigated at 25% engine load and speed of 800 rpm. Results revealed that the released heat of triple injection pulse during the expansion stroke is the same or higher than that of single and double injection pulses at specified injection timings. It affects positively the engine performance. The highest indicated mean effective pressure (IMEP) can be achieved using single injection pulse at all first injection timings. It is observed that double and triple injection pulses possess comparable indicated thermal efficiency (ITE) and IMEP to those of single injection at specified injection timings. The highest ITE is found 47.5% at first injection timing of −16 deg after top dead center (ATDC) for both single and double injection pulses. Nitrogen oxides (NOx) mole fraction generally increases when retarding the injection timing. By applying double and triple injection pulses, NOx emissions decrease, on average, by 9% and 14% compared to that of the single injection pulse. Using double and triple injection pulses, soot emissions increase, on average, by 10% and 32%, respectively, compared to single injection pulse. However, at specified injection timings, the effect of all injection pulses on soot emissions is negligible at relative advanced first injection timing. Carbon monoxide (CO) emissions decrease slightly for all injection strategies when the injection timing varies from −20 deg ATDC to −12 deg ATDC. In this range, dual-fuel operation with triple injection pulse produces the lowest CO emissions. By using triple injection pulse at suitable injection timings, CO emissions decrease by around 7.4% compared to single injection pulse. However, by applying double and triple injection pulses, unburned methane increases, on average, by 16% and 52%, respectively, compared with that of single injection pulse. However, at injection timings of −12 deg ATDC and −8 deg ATDC, triple and double injection pulses produce comparable level of unburned methane to that of single injection pulse.

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