Effect of Split Injection Timing on Combustion and Emissions of a DISI Optical Engine Under Lean Burn Condition

2020 ◽  
Author(s):  
Zhe Sun ◽  
Mingli Cui ◽  
Hongyu Wang ◽  
Mohamed Nour ◽  
Xuesong Li ◽  
...  
Keyword(s):  
High Energy ◽  
Flame Speed ◽  
Operating Conditions ◽  
Image Processing Technique ◽  
Injection Timing ◽  
Split Injection ◽  
Lean Burn ◽  
Combustion Performance ◽  
Optical Engine ◽  
Lean Combustion

Abstract Lean combustion has proven to be an effective way to improve the efficiency and emissions of the direct injection spark ignition (DISI) engine. However, one of the main problems at the lean stability limit is the major decrease in flame temperature due to dilution, resulting in a low laminar flame speed, especially under low-speed engine operating conditions. The split injection is a potential technology to realize proper air-fuel mixing and achieve different spray distribution that can help in solving such problems. In this study, split injections with different secondary injection timings were tested to achieve homogeneous and homogeneous-stratified modes in a DISI optical engine under lean-burn mode. The split ratio of each strategy was 1:1. The engine was operated at 800 rpm, and a high-energy ignition system was utilized to realize lean combustion at a lambda of 1.55. Engine combustion performance and emissions were tested while performing high-speed color recording to study the characteristics of flame chemiluminescence through a quartz piston combined with a 45-degree mirror installed below. Flame structure during various combustion phases was compared under different selected conditions based on a digital image processing technique. The results show that the pressure and emissions vary with the second injection timing. Proper control of the split injection timing can improve lean combustion performance, including faster flame speed, increased indicated mean effective pressure (IMEP), and lower harmful emissions. Poor fuel evaporation and soot generation from spatial hot spots in the combustion process of split injection are the major challenges for further improvement.

Effect of Split Injection Timing on Combustion and Emissions of a DISI Optical Engine Under Lean Burn Condition

2021 ◽  
Author(s):  
Sun Zhe ◽  
Mingli Cui ◽  
Hongyu Wang ◽  
Mohamed Nour ◽  
Xuesong Li ◽  
...  
Keyword(s):  
Injection Timing ◽  
Split Injection ◽  
Lean Burn ◽  
Optical Engine

The Research of Lean Combustion Characteristic of Compound Injection System of Direct Injection Engine

2014 ◽  
Vol 532 ◽  
pp. 362-366 ◽  
Author(s):  
Jiang Feng Mou ◽  
Rui Qing Chen ◽  
Yi Wei Lu
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Injection System ◽  
Intake Manifold ◽  
Combustion Characteristic ◽  
Injection Timing ◽  
Mixed Gas ◽  
Lean Burn ◽  
Direct Injection Engine ◽  
Lean Combustion

This paper studies the lean burn limit characteristic of the compound injection system of the direct-injection gasoline engine. The low pressure nozzle on the intake manifold can achieve quality homogeneous lean mixture, and the direct injection in the cylinder can realized the dense mixture gas near the spark plug. By adjusting the two injection timing and injection quantity, and a strong intake tumble flow with special shaped combustion chamber, it can produces the reverse tumble to form different hierarchical levels of mixed gas in the cylinder. Experimental results show: the compound combustion system to the original direct-injection engine lean burn limit raise 1.8-2.5 AFR unit.

Influence of injection strategies on knock resistance and combustion characteristics in a DISI engine

2018 ◽  
Vol 233 (10) ◽  
pp. 2637-2649
Author(s):  
Haiqiao Wei ◽  
Jie Yu ◽  
Aifang Shao ◽  
Lei Zhou ◽  
Jianxiong Hua ◽  
...  
Keyword(s):  
Single Injection ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Combustion Stability ◽  
Injection Timing ◽  
Split Injection ◽  
Injection Strategy ◽  
Double Injection ◽  
The Impact ◽  
Injection Strategies

The combustion of a direct injection spark ignition engine is significantly affected by the fuel injection strategy due to the impact this strategy has on the gas-mixture formation and the turbulence flow. However, comprehensive assessments on both knock and engine performances for different injection strategies are generally lacking. Therefore, the main objective of the present study is to provide an experimental evidence of how a single injection strategy and a split injection strategy compare in terms of both knock tendency and engine performances like thermal efficiency, torque and combustion stability. Starting from the optimization of a single injection strategy, a split injection strategy is then evaluated. Under the present operating conditions, an optimum secondary injection timing of 100 CAD BTDC is found to have significant improvements on both the knock resistance and the overall engine performances. It should be noted that the present results indicate that the relationship between double injection and anti-knock performance is not monotonous. In addition, the double injection shows superior potential in improving fuel economy and power performance in contrast with the single injection thanks to a more stable combustion when a late injection timing is applied.

Research on Control System of Quasi-Homogeneous Lean-Burn Engine

2014 ◽  
Vol 496-500 ◽  
pp. 1248-1251 ◽  
Author(s):  
Jia Jun Wang ◽  
Jun Wei Tao ◽  
Hong Da Zhang ◽  
Jin Bo Guo
Keyword(s):  
Control System ◽  
Fuel Injection ◽  
Injection Timing ◽  
Engine Fuel ◽  
Lean Burn ◽  
Engine Control System ◽  
Lean Combustion ◽  
Combustion Technology ◽  
Fuel Consumption And Emissions ◽  
Injection Pulse

Quasi-homogeneous lean mixture combustion technology can take full advantages of lean-combustion, and help reduce the engine fuel consumption and emissions. Quasi-Homogeneous Lean-burn engine Control System, combined virtual instruments with engine electronic control technology, can precisely control air-fuel ratio injection, timing, fuel injection pulse and ignite on timing, which provides a reliable and convenient platform for the engine lean-burning performance tests..

scholarly journals Towards the Hydrogen Economy—A Review of the Parameters That Influence the Efficiency of Alkaline Water Electrolyzers

Energies ◽  
2021 ◽  
Vol 14 (11) ◽  
pp. 3193
Author(s):  
Ana L. Santos ◽  
Maria-João Cebola ◽  
Diogo M. F. Santos
Keyword(s):  
Energy Content ◽  
Water Electrolysis ◽  
High Energy ◽  
Operating Conditions ◽  
Energy Sources ◽  
Alkaline Water Electrolysis ◽  
Alkaline Water ◽  
New Energy ◽  
Recent Developments ◽  
Cell Components

Environmental issues make the quest for better and cleaner energy sources a priority. Worldwide, researchers and companies are continuously working on this matter, taking one of two approaches: either finding new energy sources or improving the efficiency of existing ones. Hydrogen is a well-known energy carrier due to its high energy content, but a somewhat elusive one for being a gas with low molecular weight. This review examines the current electrolysis processes for obtaining hydrogen, with an emphasis on alkaline water electrolysis. This process is far from being new, but research shows that there is still plenty of room for improvement. The efficiency of an electrolyzer mainly relates to the overpotential and resistances in the cell. This work shows that the path to better electrolyzer efficiency is through the optimization of the cell components and operating conditions. Following a brief introduction to the thermodynamics and kinetics of water electrolysis, the most recent developments on several parameters (e.g., electrocatalysts, electrolyte composition, separator, interelectrode distance) are highlighted.

Effect of injection timing on combustion, performance and emission characteristics of CI engine fuelled with quaternary blends

2020 ◽  
Author(s):  
Anish Mariadhas ◽  
Jayaprabakar Jayaraman ◽  
Nivin Joy ◽  
P. Saikamal ◽  
P. V. S. Yaswanth ◽  
...  
Keyword(s):  
Injection Timing ◽  
Emission Characteristics ◽  
Performance And Emission ◽  
Combustion Performance ◽  
Ci Engine

Two-Stroke Marine Diesel Engine Variable Injection Timing System Performance Evaluation and Optimum Setting for Minimum Fuel Consumption at Acceptable NOx Levels

2014 ◽  
Author(s):  
Dimitrios T. Hountalas ◽  
Spiridon Raptotasios ◽  
Antonis Antonopoulos ◽  
Stavros Daniolos ◽  
Iosif Dolaptzis ◽  
...  
Keyword(s):  
Diesel Engine ◽  
Fuel Consumption ◽  
Engine Performance ◽  
Operating Conditions ◽  
Specific Fuel Consumption ◽  
Injection Timing ◽  
Nox Emissions ◽  
Pressure Measurements ◽  
Cylinder Pressure ◽  
Start Of Injection

Currently the most promising solution for marine propulsion is the two-stroke low-speed diesel engine. Start of Injection (SOI) is of significant importance for these engines due to its effect on firing pressure and specific fuel consumption. Therefore these engines are usually equipped with Variable Injection Timing (VIT) systems for variation of SOI with load. Proper operation of these systems is essential for both safe engine operation and performance since they are also used to control peak firing pressure. However, it is rather difficult to evaluate the operation of VIT system and determine the required rack settings for a specific SOI angle without using experimental techniques, which are extremely expensive and time consuming. For this reason in the present work it is examined the use of on-board monitoring and diagnosis techniques to overcome this difficulty. The application is conducted on a commercial vessel equipped with a two-stroke engine from which cylinder pressure measurements were acquired. From the processing of measurements acquired at various operating conditions it is determined the relation between VIT rack position and start of injection angle. This is used to evaluate the VIT system condition and determine the required settings to achieve the desired SOI angle. After VIT system tuning, new measurements were acquired from the processing of which results were derived for various operating parameters, i.e. brake power, specific fuel consumption, heat release rate, start of combustion etc. From the comparative evaluation of results before and after VIT adjustment it is revealed an improvement of specific fuel consumption while firing pressure remains within limits. It is thus revealed that the proposed method has the potential to overcome the disadvantages of purely experimental trial and error methods and that its use can result to fuel saving with minimum effort and time. To evaluate the corresponding effect on NOx emissions, as required by Marpol Annex-VI regulation a theoretical investigation is conducted using a multi-zone combustion model. Shop-test and NOx-file data are used to evaluate its ability to predict engine performance and NOx emissions before conducting the investigation. Moreover, the results derived from the on-board cylinder pressure measurements, after VIT system tuning, are used to evaluate the model’s ability to predict the effect of SOI variation on engine performance. Then the simulation model is applied to estimate the impact of SOI advance on NOx emissions. As revealed NOx emissions remain within limits despite the SOI variation (increase).

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