Characteristics of Diesel Spray With Varying Injection Rate

2019 ◽  
Author(s):  
Intarat Naruemon ◽  
Long Liu ◽  
Dai Liu ◽  
Xiuzhen Ma
Keyword(s):  
Ignition Time ◽  
Fuel Mixture ◽  
Injection Rate ◽  
Diesel Spray ◽  
Low Temperature Combustion ◽  
Multiple Injection ◽  
Injection Duration ◽  
Injection Process ◽  
Temperature Combustion ◽  
Combustion Processes

Abstract Multiple-injection is an effective injection strategy in order to control the advanced combustion processes in diesel engines. However, because of the multiple-injection application, cause the duration of each injection is shortened, such as the pilot injection and post-injection. The short injection duration results in a very short quasi-steady injection process so that the ramping-up and ramping-down injection processes occupied a much larger scale during the injection. As a result, this circumstance of the spray evolution not been fully understood. To investigate the diesel spray propagation with varying injection rate, visual experiments and numerical simulation analyses on diesel spray were performed. The penetrations of diesel sprays with short injection duration were obtained by reflected shadowgraphy in a combustion chamber’s constant-volume with the multi-hole injector. The diesel spray with varying injection rates was modeled by using CONVERGE CFD software and the model was calibrated and validated by the experimental data. Then diagnosed the spray characteristics including spray penetration, Sauter means diameter, as well as fuel concentration distribution, were analyzed with different injection quantities and injection rate shapes. The spray mixing analysis included that after the end-of-injection in order to consider the low-temperature combustion phenomenon. The shape of the improved injection rate in the fuel mixture considered in the case of injection ending before or after the ignition time was summarized for different conditions.

Multiple injection strategies for reducing HC and CO emissions in diesel-methane dual-fuel low temperature combustion

Fuel ◽  
2021 ◽  
Vol 305 ◽  
pp. 121372
Author(s):  
Deivanayagam Hariharan ◽  
Sundar Rajan Krishnan ◽  
Kalyan Kumar Srinivasan ◽  
Aamir Sohail
Keyword(s):  
Low Temperature ◽  
Dual Fuel ◽  
Low Temperature Combustion ◽  
Multiple Injection ◽  
Temperature Combustion ◽  
Injection Strategies

scholarly journals A Study of Combustion Characteristics of Two Gasoline–Biodiesel Mixtures on RCEM Using Various Fuel Injection Pressures

Energies ◽  
2020 ◽  
Vol 13 (12) ◽  
pp. 3265
Author(s):  
Ardhika Setiawan ◽  
Bambang Wahono ◽  
Ocktaeck Lim
Keyword(s):  
Heat Release ◽  
Ignition Delay ◽  
Fuel Injection ◽  
Injection Pressure ◽  
Fuel Mixture ◽  
Injection Rate ◽  
Injection Duration ◽  
Late Start ◽  
Fuel Injection Rate ◽  
Injection Pressures

Experimental research was conducted on a rapid compression and expansion machine (RCEM) that has characteristics similar to a gasoline compression ignition (GCI) engine, using two gasoline–biodiesel (GB) blends—10% and 20% volume—with fuel injection pressures varying from 800 to 1400 bar. Biodiesel content lower than GB10 will result in misfires at fuel injection pressures of 800 bar and 1000 bar due to long ignition delays; this is why GB10 was the lowest biodiesel blend used in this experiment. The engine compression ratio was set at 16, with 1000 µs of injection duration and 12.5 degree before top dead center (BTDC). The results show that the GB20 had a shorter ignition delay than the GB10, and that increasing the injection pressure expedited the autoignition. The rate of heat release for both fuel mixes increased with increasing fuel injection pressure, although there was a degradation of heat release rate for the GB20 at the 1400-bar fuel injection rate due to retarded in-cylinder peak pressure at 0.24 degree BTDC. As the ignition delay decreased, the brake thermal efficiency (BTE) decreased and the fuel consumption increased due to the lack of air–fuel mixture homogeneity caused by the short ignition delay. At the fuel injection rate of 800 bar, the GB10 showed the worst efficiency due to the late start of combustion at 3.5 degree after top dead center (ATDC).

Application of Dynamic ϕ–T Map: Analysis on a Natural Gas/Diesel Fueled RCCI Engine

2016 ◽  
Vol 138 (9) ◽  
Author(s):  
Jing Li ◽  
Wenming Yang ◽  
Hui An ◽  
Dezhi Zhou ◽  
Markus Kraft
Keyword(s):  
Natural Gas ◽  
Soot Formation ◽  
Combustion Process ◽  
Diesel Oil ◽  
Chemical Mechanism ◽  
Low Temperature Combustion ◽  
Injection Duration ◽  
Start Of Injection ◽  
Temperature Combustion ◽  
Map Analysis

In this study, dynamic ϕ–T map analysis was applied to a reactivity controlled compression ignition (RCCI) engine fueled with natural gas (NG) and diesel. The combustion process of the engine was simulated by coupled kiva4-chemkin with a diesel oil surrogate (DOS) chemical mechanism. The ϕ–T maps were constructed by the mole fractions of soot and NO obtained from senkin and ϕ–T conditions from engine simulations. Five parameters, namely, NG fraction, first start of injection (SOI) timing, second SOI timing, second injection duration, and exhaust gas recirculation (EGR) rate, were varied in certain ranges individually, and the ϕ–T maps were compared and analyzed under various conditions. The results revealed how the five parameters would shift the ϕ–T conditions and influence the soot–NO contour. Among the factors, EGR rate could limit the highest temperature due to its dilute effect, hence maintaining RCCI combustion within low-temperature combustion (LTC) region. The second significant parameter is the premixed NG fraction. It could set the lowest temperature; moreover, the tendency of soot formation can be mitigated due to the lessened fuel impingement and the absence of C–C bond. Finally, the region of RCCI combustion was added to the commonly known ϕ–T map diagram.

scholarly journals Low Temperature Combustion with Multiple Injection Strategies in Single Cylinder Diesel Engine

2020 ◽  
Vol 9 (7) ◽  
pp. 779-785
Keyword(s):  
Low Temperature ◽  
Exhaust Gas Recirculation ◽  
Exhaust Gas ◽  
Low Temperature Combustion ◽  
Multiple Injection ◽  
Engine Emissions ◽  
Multiple Injections ◽  
Temperature Combustion ◽  
Gas Recirculation ◽  
Injection Strategies

Low-temperature combustion(LTC) with multiple injection strategies is a recent trend for NOx and soot reduction in single-cylinder diesel engines. This paper presents a technical study of past research carried out on multiple injections, which are pilot I and pilot II injection before main injection, to decrease engine soot to meet emission legislation while upholding efficiency and decrease or eliminate exhaust after treatment. Previous research indicates that extending ignition lag to enhance the proper premixing, and controlling temperature of combustion to optimal level using Exhaust Gas Recirculation, have been accepted as an important aspect to attain low temperature combustion. In this paper, we first discuss the effect pilot I injection and pilot II injection strategy through varied injection quantity and time range. Thereafter, we briefly review how pilot II injection provides better results compared with the pilot I injection, which is by reason of better premixing, improves the turbulent effect and lowers the emission. Next, we provide a broad overview of the collected works on the effect of injection pressure, temperature and rate of exhaust gas recirculation on engine emissions. We conclude by identifying a few dependencies of engine parameters in low-temperature combustion by multiple injections so as to reduce the engine emissions.

scholarly journals Investigation on an Injection Strategy Optimization for Diesel Engines Using a One-Dimensional Spray Model

Energies ◽  
2019 ◽  
Vol 12 (21) ◽  
pp. 4221
Author(s):  
Intarat Naruemon ◽  
Long Liu ◽  
Qihao Mei ◽  
Xiuzhen Ma
Keyword(s):  
Diesel Engines ◽  
Injection Rate ◽  
Pollutant Emission ◽  
Gas Jet ◽  
Entrainment Rate ◽  
Multiple Injection ◽  
Mixing Process ◽  
Injection Strategy ◽  
One Dimensional ◽  
Injection Duration

Common rail systems have been widely used in diesel engines due to the stricter emission regulations. The advances in injector technology and ultrahigh injection pressure greatly promote the development of multiple-injection strategy, leading to the shorter injection duration and more variable injection rate shape, which makes the mixing process more significant for the formation of pollutant emission. In order to study the mixing process of diesel sprays under variable injection rate shapes and find the optimized injection strategy, a one-dimensional spray model was modified in this paper. The model was validated by the measured spray penetrations based on shadowgraphy experiments with the varying injection rate. The simulations were performed with five injection rate shapes, triangle, ramping-up, ramping-down, rectangle and trapezoid. Their spray penetrations, entrainment rates and equivalence ratios along spray axial distance are compared. The potentials of multiple-injection and gas-jet after end-of-injection (EOI) to improve mixing process and emission reduction are discussed finally. The results indicated that ramping-up injection rate obtains the highest entrainment rate after EOI, and it needs 1.5 times of injection duration for the entrainment wave to arrive at the spray tip. For the other four injection rates, the sprays can be treated as a steady-like state, needing twice of injection duration from EOI to the time the entrainment wave reaches the spray tip. The multiple-injection with proper injection rate shape enhanced the entrainment rate, and the gas-jet after EOI affected the mixture distribution and entrainment rate in spray tail under ramping-down injection rate.

Investigation on online measurement method of injection rate for high pressure common rail diesel engine injector on multiple-injection strategies

2021 ◽  
Author(s):  
Xiyu Yang ◽  
Quan Dong ◽  
Jingdong Song ◽  
Tanqing Zhou
Keyword(s):  
High Pressure ◽  
Diesel Engine ◽  
Real Time ◽  
Measurement Method ◽  
Fuel Injection ◽  
Water Hammer ◽  
Injection Rate ◽  
Online Measurement ◽  
Multiple Injection ◽  
Injection Process

Abstract As a state-of-the-art injection technology, high-pressure common rail injection system (HPCRIS) has advantages including high injection pressure, adjustable injection timing and flexible injection rate. Nevertheless, the fluctuation of cyclic fuel injection mass (CFIM) in HPCRIS with multiple-injection strategy (MIS) reduces the economy of diesel engine and the stability of vibration and noise control. To realize the precise control of CFIM, the online perception of injection process is the premise. This paper presents an innovative online measurement method of injection rate on MIS. According to the evolution characteristics of water hammer pressure oscillation in the fuel system, the rule is found that the oscillation form of the water hammer is depended on the structure of HPCRIS rather than the injection condition, and the general applicability of this rule is proved by the hydraulic-electric analog method. Base on this, the real-time simulation method of the pilot water hammer oscillation wave in the same field is proposed to realize the extraction of the expansion pressure signal components of the main injection. Then the direct mathematical relationship between pressure signal and fuel injection rate is established, and the online measurement of fuel injection characteristics under MIS is realized. To improve the robustness of the algorithm a real-time calibration method of fuel sound velocity is proposed. Finally, by comparing with the offline experiment, this online measurement method of injection rate has relatively high accuracy, the CFIM error is less than 2%, and the fitting goodness of the injection rate curve exceeded 0.91. This measurement method can provide direct feedback to the electronic control unit (ECU) on the fuel injection process without changing the HPCRIS structure.

Ethylperoxy radical: approaching spectroscopic accuracy via coupled-cluster theory

2017 ◽  
Vol 19 (24) ◽  
pp. 15715-15723 ◽  
Author(s):  
Andrew M. Launder ◽  
Justin M. Turney ◽  
Jay Agarwal ◽  
Henry F. Schaefer
Keyword(s):  
Excited State ◽  
Low Temperature ◽  
Coupled Cluster ◽  
Low Temperature Combustion ◽  
Coupled Cluster Theory ◽  
Cluster Theory ◽  
Temperature Combustion ◽  
Combustion Processes

Highly reliable ground and excited state properties of the conformers of ethylperoxy radical are predicted using coupled-cluster theory. This research has implications for future characterization of intermediates in tropospheric and low-temperature combustion processes.

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