Predictions of Charge Drift in a Concept Electrosprayed DISI Engine

2006 ◽  
Vol 128 (5) ◽  
pp. 903-912 ◽  
Author(s):  
Geraldo C. S. Nhumaio ◽  
A. Paul Watkins
Keyword(s):  
Direct Injection ◽  
Direct Simulation Monte Carlo ◽  
Combustion Efficiency ◽  
Electrical Charge ◽  
Cylinder Wall ◽  
Spark Plug ◽  
Discrete Phase ◽  
Multiple Injection Strategy ◽  
Wall Wetting ◽  
Direct Injection Spark Ignition

Limited to nonvaporizing spray cases, this work discusses the transport of charged droplets within a cylinder of a motored axisymmetric model electrosprayed direct injection spark ignition (eDISI) engine with electrified walls. The concept engine investigated here is assumed to operate with an electrostatic atomizer previously studied for application in fuel burners [Yule et al., 1994, Fuel, 74(7), pp. 1094–1103]. A split/multiple injection strategy is employed in which three pulses of 5mg each are made at crank angles of 80, 150 and 300 deg ATDC of the intake, which fall within the intervals for stable combustion of either early or late injection modes of operation of DISI engines [Jackson et al., 1997, SAE Paper No. 970543]. The direct Simulation Monte Carlo (DSMC) approach embodied in an in-house CFD research code is used to simulate the discrete phase flow with the electrical charge distribution for different instants within the computational cells being computed by simple addition of the droplet charges residing in particular cells at particular instants of time. It is shown in the half engine cycle investigated that the use of charged sprays in eDISI engines may help to reduce the in-cylinder wall-wetting phenomenon. In addition, pockets of highest electrical charge are found to populate the region near the spark plug by 345 deg CA, which may be a path for improved combustion efficiency.

The effects of cylinder deactivation on the thermal behaviour and fuel economy of a three-cylinder direct injection spark ignition gasoline engine

2018 ◽  
Vol 233 (11) ◽  
pp. 2838-2849
Author(s):  
Michael McGhee ◽  
Ziman Wang ◽  
Alexander Bech ◽  
Paul J Shayler ◽  
Dennis Witt
Keyword(s):  
Fuel Economy ◽  
Gasoline Engine ◽  
Thermal State ◽  
Direct Injection ◽  
Spark Ignition ◽  
Combustion Efficiency ◽  
Spark Ignition Engine ◽  
Engine Fuel ◽  
Cylinder Deactivation ◽  
Direct Injection Spark Ignition

The changes in thermal state, emissions and fuel economy of a 1.0-L, three-cylinder direct injection spark ignition engine when a cylinder is deactivated have been explored experimentally. Cylinder deactivation improved engine fuel economy by up to 15% at light engine loads by reducing pumping work, raising indicated thermal efficiency and raising combustion efficiency. Penalties included an increase in NOx emissions and small increases in rubbing friction and gas work losses of the deactivated cylinder. The cyclic pressure variation in the deactivated cylinder falls rapidly after deactivation through blow-by and heat transfer losses. After around seven cycles, the motoring loss is ~2 J/cycle. Engine structural temperatures settle within an 8- to 13-s interval after a switch between two- and three-cylinder operation. Engine heat rejection to coolant is reduced by ~13% by deactivating a cylinder, extending coolant warm-up time to thermostat-opening by 102 s.

scholarly journals Effect of engine conditions and injection timing on piston-top fuel films for stratified direct-injection spark-ignition operation using E30

2019 ◽  
Vol 21 (2) ◽  
pp. 302-318 ◽  
Author(s):  
Carl-Philipp Ding ◽  
David Vuilleumier ◽  
Namho Kim ◽  
David L Reuss ◽  
Magnus Sjöberg ◽  
...  
Keyword(s):  
Refractive Index ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Injection Timing ◽  
Fuel Film ◽  
Index Matching ◽  
Refractive Index Matching ◽  
Wall Wetting ◽  
Direct Injection Spark Ignition

Mid-level ethanol/gasoline blends can provide knock resistance benefits for stoichiometric spark-ignition engine operation, but previous studies have identified challenges associated with spray impingement and wall wetting, leading to excessive particulate matter emissions. At the same time, stratified-charge spark-ignition operation can provide increased thermal efficiency, but care has to be exercised to avoid excessive in-cylinder soot formation. In support of the use of mid-level ethanol/gasoline blends in advanced spark-ignition engines, this study presents spray and fuel-film measurements in a direct-injection spark-ignition engine operated with a 30 vol.%/70 vol.% ethanol/gasoline blend (E30). Crank-angle resolved fuel-film measurements at the piston surface are conducted using two different implementations of the refractive index matching technique. A small-angle refractive index matching implementation allows quantification of the wetted area, while a large-angle refractive index matching implementation enables semi-quantitative measurements of fuel-film thickness and volume, in addition to fuel-film area. The fuel-film measurements show that both the amount of fuel deposited on the piston and the shape of the fuel-film patterns are strongly influenced by the injection timing, duration, intake pressure, and coolant temperature. For combinations of high in-cylinder gas density and long injection duration, merging of the individual spray plumes, commonly referred to as spray collapse, can cause a dramatic change to the shape and thickness of the wall fuel films. Overall, the study provides guidance to engine designers aiming at minimizing wall wetting through tailored combinations of injection timings and durations.

Further Experiments on the Effects of In-Cylinder Wall Wetting on HC Emissions from Direct Injection Gasoline Engines

1999 ◽  
Author(s):  
Jianwen Li ◽  
Ronald D. Matthews ◽  
Rudolf H. Stanglmaier ◽  
Charles E. Roberts ◽  
Richard W. Anderson
Keyword(s):  
Direct Injection ◽  
Cylinder Wall ◽  
Gasoline Engines ◽  
Hc Emissions ◽  
Wall Wetting

Simulation of electrosprays in model direct-injection spark-ignition engine in-cylinder flows

2005 ◽  
Vol 6 (6) ◽  
pp. 527-546 ◽  
Author(s):  
G C S Nhumaio ◽  
A P Watkins
Keyword(s):  
Direct Injection ◽  
Axisymmetric Flow ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Cylinder Wall ◽  
Half Cycle ◽  
Fuel Film ◽  
Reference Case ◽  
Multiple Pulses ◽  
Direct Injection Spark Ignition

The calculated effects on injected charged sprays of dielectric and conductive in-cylinder wall materials are presented for a half-cycle of an axisymmetric flow model direct-injection spark-ignition (DISI) engine. A plain orifice electrostatic atomizer, previously used in experiments for application in fuel burners, is embodied into the EPISO code and this is assumed to pump a charged spray while working at moderate pressures of 5 MPa and fuel deliveries of 5 cm3/s, the maximum rates currently reported in electrostatic atomization of hydrocarbons. The transition mode operation of DISI engines is selected for the study and this consists of multiple pulses of 5 mg each, occurring at 80, 150, and 300° crank angle with the engine running at 3000 r/min. In the case of the third pulse, which impinges on the piston surface, the wall impaction model of Park and Watkins is used particularly when an electric potential of 1 kV is applied on this surface for it helps to reduce excessive fuel film build-up. Particles impinging on the cylinder roof and liner are treated with the stick impaction model of Naber and Reitz. A simple axisymmetric engine geometry of flat piston and cylinder heads is considered and computations of an uncharged spray are taken as a reference case. It is found in the study, firstly, that charge improves mixture preparation when dielectric in-cylinder surfaces are used, secondly, that the need for charge drainage in metallic surfaces produces poor spray characteristics in comparison with an ideal charged spray with boundary electric fields (this is shown by the large impingement of drop parcels relative to an ordinary spray as well as to a charged spray with electric boundary fields) and, thirdly, that charge reduces the fuel film thickness on the piston surface during late injection.

Spray Development and Wall Impingement of Ethanol and Gasoline in an Optical Direct Injection Spark Ignition Engine

2015 ◽  
Author(s):  
Mohammad Fatouraie ◽  
Margaret S. Wooldridge ◽  
Benjamin R. Petersen ◽  
Steven T. Wooldridge
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Coolant Temperature ◽  
Absolute Pressure ◽  
Injection Timing ◽  
Cylinder Wall ◽  
Wall Impingement ◽  
Direct Injection Spark Ignition

The effects of ethanol on spray development and wall impingement of a direct injection spark ignition (DISI) engine was investigated using high-speed imaging of the fuel spray in an optically-accessible engine. Neat anhydrous ethanol (E100), reference grade gasoline (E0) and a 50% blend (by volume) of gasoline and ethanol (E50) were used in the study. The experiments were conducted using continuous firing conditions for an intake manifold absolute pressure of 57 kPA, and engine speed of 1500 RPM. Retarded fuel injection timing was used (with start of injection at 250 °bTDC) to isolate the effects of cylinder wall impingement, and lean fuel-to-air ratios (ϕ=0.8–0.9) were used to minimize sooting and coating of the transparent cylinder liner. The effects of three engine coolant temperatures (25, 60 and 90 °C) and two fuel rail pressures (100 and 150 bar) on the features of the spray and the spray interaction with the wall were studied for the different fuels. Quantitative metrics were defined to analyze the spatial features of the spray related to wall impingement. Gasoline (E0) sprays exhibited higher sensitivity to coolant temperature compared to ethanol (E100) in terms of the shape of the spray and wall impingement. Higher fuel injection pressure increased the spray tip penetration rate and fuel impingement with the wall for E0 and E100, despite creating wider plume angles of the fuel sprays.

Study on Mixture Formation of Liquid LPG for a Center Injection DISI Engine

2011 ◽  
Vol 201-203 ◽  
pp. 622-626 ◽  
Author(s):  
Bo Yan Xu ◽  
De Zhi Sun ◽  
Yun Liang Qi ◽  
Yong Wei Zheng ◽  
Hai Ying Tian ◽  
...  
Keyword(s):  
Direct Injection ◽  
Spark Ignition Engines ◽  
Liquefied Petroleum Gas ◽  
Mixture Formation ◽  
Stratified Charge ◽  
Unburned Hydrocarbon ◽  
Hydrocarbon Emission ◽  
Wall Wetting ◽  
Direct Injection Spark Ignition ◽  
Early Injection

Center injection in pentroof combustion chamber can reduce wall wetting and unburned hydrocarbon emission in wall guided combustion system, which is generally employed in DISI (Direct Injection Spark Ignition) engines. Once liquid phase LPG (Liquefied Petroleum Gas) is injected at a high pressure, flash boiling occurs severely, promotes mixing and reduces wall wetting in wall guided engine. Based on validating the feasibility of the models, this paper numerically simulates the mixing process of a center injection wall guided DISI engine in different conditions. The results show that a stratified charge can obtained at part load with late injection, whereas at high load the early injection can achieve a homogeneous mixture at the end of compression stroke.

Experimental Investigation of Two Stroke Direct Injection Spark Ignition Engine

2014 ◽  
Author(s):  
K. D. Sapate ◽  
A. N. Tikekar
Keyword(s):  
Fuel Consumption ◽  
Fuel Injection ◽  
Low Cost ◽  
Direct Injection ◽  
Weight Ratio ◽  
Spark Ignition Engine ◽  
Cylinder Block ◽  
Spark Plug ◽  
High Level ◽  
Direct Injection Spark Ignition

From its inception, the two-stroke cycle SI engine has been criticized for its high specific fuel consumption and too high level of emission of unburnt hydrocarbon (HC) and carbon monoxide (CO) during scavenging. These engines are used mainly due to its positive advantages of simplicity, low cost, higher power to weight ratio, low maintenance etc. for example, in two wheelers, outboard motor boats etc. In the present innovation, fuel is injected through injector mounted on the cylinder block facing spark plug, directly into the cylinder after closing both the inlet end exhaust port. The quantity of fuel injection is decided by developed electronic fuel injection control circuit based on two important parameters of engine namely load and speed. In this circuit, two input sensors namely throttle position sensor and speed & crank sensor is used along with developed software to control the quantity of fuel injection. After long experimentation with different locations of injector, sensors, etc., for selected two stroke engine, it has been observed that the power output has improved by 5%, reduction of fuel consumption by 20%, a reduction of HC and CO by 35% and 25% respectively, in injection mode.

The Effect of Intake Valve Deactivation on Lean Stratified Charge Combustion at an Idling Condition of a Spark Ignition Direct Injection Engine

2012 ◽  
Vol 134 (9) ◽  
Author(s):  
Ronald O. Grover ◽  
Junseok Chang ◽  
Edward R. Masters ◽  
Paul M. Najt ◽  
Aditya Singh
Keyword(s):  
Laminar Flame ◽  
Direct Injection ◽  
Combustion Process ◽  
Spark Ignition ◽  
Combustion Efficiency ◽  
Combustion Stability ◽  
Charge Motion ◽  
Piston Bowl ◽  
Light Load ◽  
Spark Plug

A combined experimental and analytical study was carried out to understand the improvement in combustion performance of a four-valve spark ignition direct injection (SIDI) wall-guided engine operating at lean, stratified idle with enhanced in-cylinder charge motion by deactivating one of the two intake valves. A fully warmed-up engine was operated at low speed, light load by injecting the fuel from a pressure-swirl injector during the compression stroke to produce a stratified fuel cloud surrounding the spark plug at the time of ignition. Steady state flow-bench measurements and computational fluid dynamics (CFD) calculations showed that valve deactivation primarily increased the in-cylinder swirl intensity as compared with opening both intake valves. Engine dynamometer measurements showed an increase in charge motion led to improved combustion stability, increased combustion efficiency, lower fuel consumption, and higher dilution tolerance. A CFD study was conducted using in-house models of spray and combustion to simulate the engine operating with and without valve deactivation. The computations demonstrated that the improved combustion was primarily driven by higher laminar flame speeds through enhanced mixing of internal residual gases, better containment of the fuel cloud within the piston bowl, and higher postflame diffusion burn rates during the initial, main, and late stages of the combustion process, respectively.

scholarly journals Effects of mixture formation strategies on combustion in dual-fuel engines – a review

2021 ◽  
Vol 184 (1) ◽  
pp. 30-40
Author(s):  
Ireneusz Pielecha ◽  
Maciej Sidorowicz
Keyword(s):  
Internal Combustion Engines ◽  
Direct Injection ◽  
Combustion Process ◽  
Critical Factor ◽  
Diesel Oil ◽  
Combustion Efficiency ◽  
Dual Fuel ◽  
Compression Ignition ◽  
Mixture Formation ◽  
Spark Plug

The article presents an overview of technical solutions for dual fuel systems used in internal combustion engines. It covers the historical and contemporary genesis of using two fuels simultaneously in the combustion process. The authors pay attention to the value of the excess air coefficient in the cylinder, as the ignitability of the fuel dose near the spark plug is a critical factor. The mixture formation of compression ignition based systems are also analyzed. The results of research on indirect and direct injection systems (and their combinations) have been presented. Research sections were separated based to the use of gasoline with other fuels or diesel oil with other fuels. It was found that the use of two fuels in different configurations of the fuel supply systems extends the conditions for the use of modern combustion systems (jet controlled compression ignition, reactivity controlled compression ignition, intelligent charge compression ignition, premixed charge compression ignition), which will enable further improvement of combustion efficiency.

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