Created: Mar 11, 2018 | 09:37
Description
Detonation mode transition and control under
wide range of temperature and pressure
Abstract：
Detonation is the key scientific issue in aerospace engines and advanced internal combustion engines under extreme operating condition. This project focuses on the key research plan of fundamental turbulent combustion research faced to engine to investigate the common scientific issues of engine combustion. To investigate the detonation mode transition and control in combustion engines, three key scientific research problems are researched, which include coupling mechanism of shock wave, turbulence and chemical reactions; numerical models and methods of detonation; mode control of engine detonation. Advanced detonation combustion test platform, numerical simulation methods and laser measurement technology are used systematically in this project. The DDT (Deflagration to Detonation Transition) mechanism will be investigated. The coupling mechanism of multiple hot-spots, multiple flame fronts and combustion chamber walls to induce DDT will be studied. The effect of shock, turbulence and its eddy structure on detonation combustion, and its mechanism will be investigated. The control method and its mechanism of suppressing or promoting detonation will be investigated. The detonation mechanism will be revealed. The new combustion model concerning shock wave propagation and its effect on combustion will be developed. The detonation combustion calculation method of adaptive mesh and adaptive chemistry will be studied. The new suppressing methods in internal combustion engine and new promoting methods in detonation engines will be proposed. The combustion theory will be extended. Furthermore, the achievement will guide the independent development of high efficiency and clean combustion engines in China.Detonation is the key scientific issue in aerospace engines and advanced internal combustion engines under extreme operating condition. This project focuses on the key research plan of fundamental turbulent combustion research faced to engine to investigate the common scientific issues of engine combustion. To investigate the detonation mode transition and control in combustion engines, three key scientific research problems are researched, which include coupling mechanism of shock wave, turbulence and chemical reactions; numerical models and methods of detonation; mode control of engine detonation. Advanced detonation combustion test platform, numerical simulation methods and laser measurement technology are used systematically in this project. The DDT (Deflagration to Detonation Transition) mechanism will be investigated. The coupling mechanism of multiple hot-spots, multiple flame fronts and combustion chamber walls to induce DDT will be studied. The effect of shock, turbulence and its eddy structure on detonation combustion, and its mechanism will be investigated. The control method and its mechanism of suppressing or promoting detonation will be investigated. The detonation mechanism will be revealed. The new combustion model concerning shock wave propagation and its effect on combustion will be developed. The detonation combustion calculation method of adaptive mesh and adaptive chemistry will be studied. The new suppressing methods in internal combustion engine and new promoting methods in detonation engines will be proposed. The combustion theory will be extended. Furthermore, the achievement will guide the independent development of high efficiency and clean combustion engines in China.
Created: Mar 28, 2018 | 09:32
Description
Fundamental Investigation of Pre-ignition and Super-knock under High Power-density Gasoline Engine Conditions
Abstract:
Pre-ignition and super-knock are the main obstacle to achieve energy saving and emission reduction in high power-density gasoline engine. They are also the key scientific issues in advanced internal combustion engines under extreme combustion condition. This project focuses on three key scientific research problems, including the ignition mechanism for particles in high pressure and high temperature combustible mixture under internal combustion engine conditions (pre-ignition mechanism), detonation initiation mechanism in the closed system (super-knock mechanism) and the control of deflagration and detonation in gasoline engine (suppressing methods). Advanced laser measurement, rapid compression machine experiment and strengthened engine test are adopted to investigate these three aspects. The origin of pre-ignition in high power-density gasoline engine will be identified and the pre-ignition mechanism in high pressure and high temperature combustible mixture will be clarified. Theory for the combustion system design in real engine will be provided. The condition required for detonation initiation will be proposed, the super-knock mechanism in a high pressure and high temperature closed system will be developed, and the detailed transition process from deflagration to detonation will be revealed. The new knock-suppression methods in high power-density gasoline engine will be proposed, with its control mechanism revealed and its practicability explored. The research in this project is of important theoretical value to high efficiency and high power-density engine combustion, and it is of great realistic significance to the industrialization application of the ultra boosted engine.
Main research topics:
1 Combustion diagnose for pre-ignition induced by lubricating oil droplet
2 Combustion diagnose for pre-ignition induced by solid particle
3 The influence rule of fuel quality for pre-ignition
4 Environmental conditions for the occurrence of super-knock
5 Restraint strategies for pre-ignition and super-knock
Created: Mar 28, 2018 | 09:36
Description
Development of Pre-ignition Mechanism and Control Strategy in Geely Methanol Engine [No.NBF1712A00197]
Abstract：
Under the background of clean energy production and utilization, the increasing attention to oxygen-containing fuel has been paid by OEMs and engine research institutes. In the application of oxygen-containing fuel, the phenomenon of pre-ignition but knock-free occurs in the domestic 3M100T methanol engine, which causes the failure of knock sensor and the engine cannot pass the durability test. The property of "pre-ignition non-knock" in methanol is a great barrier to the real-time pre-ignition detection. There is the potential way to detect pre-ignition and mitigate the propensity of pre-ignition through existing sensors, which can save engine cost and reduce the difficulty of process. This project aims to propose an real-time early detection method for real vehicle environment based on existing sensor signals through horizontal cooperation between schools and enterprises and pre-ignition mechanism controlled by chemical kinetics process will be analyzed, which can give the guidance for the development of down-sizing, direction injection engines.
Created: Mar 29, 2018 | 09:12
Description
The Mechanism and Restraint Strategy for Pre-ignition and Super-knock in Gasoline Direct Injection Engine
Abstract:
With the fuel consumption and emission regulations becoming more and more strict, high boosted gasoline direct injection (GDI) engine with small displacement has been paid more and more attention to. However, the abnormal combustion phenomena such as low-speed pre-ignition (LSPI) occurring during engine intensify limit the potential of energy-saving. Thus, the analysis of abnormal combustion phenomena in GDI engine and its solution are extremely urgent. Although many lubricating oil companies have performed many kinds of research about LSPI, the mechanism behind the phenomena is still needed to be understood deeply. The targets of this project are to obtain a deep mechanism for pre-ignition and super-knock and its feasible solutions, as well as improve the thermal effciency of GDI engine, based on the analysis of abnormal combustion phenomena, the comparison with the latest combustion control technology, and the detection of induction factors for pre-ignition. An injection strategy of once every 4 cycles for the injection of lubricating oil has been developed to test the pre-ignition and super-knokc in engine induced by the lubricating oil. The effect on pre-ignition and super-knock of the additives in lubricating oil has also been studied on engine test.
Table.1 Oil samples and the corresponding properties
Figure.1 Engine test protocol for pre-ignition and super-knock
Created: Mar 29, 2018 | 09:12
Description
Investigation of Fuel Design and Premixed Low Temperature Combustion of Wide Distillation Fuel
Abstract
The gasoline engine has low emissions but low thermal efficiency, while diesel engine has high thermal efficiency but high emissions. WDF premixed low-temperature combustion combines the advantage of gasoline and diesel fuel as well as combustion mode, which is a promising technological approach for high-efficiency and clean combustion. To achieve a high-efficiency and clean combustion in the whole operating load range by using WDF premixed low-temperature combustion, this project combined fuel design with new combustion mode, reducing soot emissions by premixed combustion, reducing NOx emissions by low-temperature combustion. High-efficiency and clean combustion were achieved by combining both above.
Main research items
(1) The main design principles for WDF was proposed, engine experimental results have shown that WDF with such properties can achieve both low-load stability and high-load emissions, exhibiting good energy-saving and emission-reducing effects.
(2) Polymethoxy Dimethyl ether (PODE) with high oxygen content and high cetane number were used to temper gasoline/diesel WDF, soot emissions were significantly reduced by combining premixing combustion and fuel oxygen-containing. The tradeoff between NOx and soot emissions from compression ignition combustion was broken.
(3) The low-temperature combustion process controlling method was proposed. Based on the high volatility and high ignitability of WDF, a new combustion organization method was proposed which combustion WDF with multiple premixed compression ignitions. Twice temporally and spatially distributed combustion was realized, breaking the trade-off between NOx and soot and between combustion noise and fuel consumption.
(4) A simplified industrial fuel refining method for WDF was proposed, including low-octane number gasoline and that diesel and gasoline are not separated distillate during refining.
(5) To improve combustion quality, cetane number improver was added to gasoline/diesel blend WDF to increase ignitability and maintain volatility. Through this method, the cetane number of gasoline/diesel blend WDF was increased significantly, the coefficient of variation of was reduced at low load, and thermal efficiency was improved significantly.
(6) A multi-component simplified mechanism for WDF which covers the distillation range of gasoline and diesel, and reflects the physical and chemical properties of WDF was proposed. The simplified mechanism can save calculation time significantly while ensuring the predicting accuracy.
Created: Apr 08, 2018 | 15:10
Description
Fundamental Study on the Sooting Characteristics of Liquid Fuels with Different Molecular Structures
Abstract:
Emission characteristics are mainly influenced by fuel properties, but the effect of the molecular structure on process of soot formation and particulate matter (PM) development has not been proved. This task intends to focus on the formation and development of soot and PM with molecular structures of different oxygen fuels in the direct injection diesel engine. The generation mechanism of soot precursor, the mathematical model of particulate matter population and the principles of low-particle-emission oxygenated fuel design were also investigated. Advanced engine bench test, optical diagnostic platform and numerical simulation were used to carry out the impact of fuel molecular structures on engine soot and particulate matter emissions. The final task is to obtain the influence of fuel molecular structure on the emission of engine smoke and the evolution of particulate matter, and come up with the design principle of oxygenated fuel with low particulate matter emission. At the same time, we need to develop an accurate mathematical model of soot precursor and particulate matter population in order to obtain the mechanism of the formation of soot particles. Finally, vehicles with low PM emissions are obtained combing with the advance methods of engine control. The results of this project have important theoretical value for the development of oxygenated fuels for compression ignition engines and important practical significance for a new generation of engine meeting emission standards.
Researches:
1) Do foundational researches about the effects of molecular structures of different fuels on soot formation.
2) Develop the generation mechanism of soot precursor.
3) Develop an accurate mathematical model of particulate matter population.
4) Find the influence of oxygen fuels of different molecular structures on the emission of engine smoke.
5) Do researches about spray features, combustion and soot formation on optical diagnostic platform.
6) Optimize the components of the fuel and measure the soot emission on engine bench test and full vehicle test.
Created: Jun 09, 2018 | 22:04
Description
Characteristics and Modeling of Plug-in/Range Extended Hybrid Engine
Abstract：
Promotion of hybrid electric vehicles (HEVs) is a significant method to fulfill energy saving and emission reduction in automotive field while the hybrid engine is one of the symbols of hybrid technology of new generation. Currently, HEVs are usually equipped with conventional engines through re-calibration and selection, which is hard to match with vehicle configurations and design. Meanwhile, there is no unified standard for the hybrid system in domestic and international industries for its control strategies, characteristics of hybrid engines, testing analysis methods, and forward development process. Based on the National Key Research and Development Program of China, further excavate the potential of saving energy and emission reduction of hybrid technology. Through the test and characteristic analysis of advanced hybrid engines, build up the engine model and then propose the scheme for dedicated hybrid engines, which can further improve the forward development of hybrid engines and accelerate the realization of hybrid technology of new generation in China.
