Simulation Research on Matching of Spray and Combustion Chamber Geometry in Diesel Engine

2011 ◽  
Vol 199-200 ◽  
pp. 193-197 ◽  
Author(s):  
Cheng Cheng Zhang ◽  
Qian Wang ◽  
Zhi Xia He ◽  
Ping Jiang

In order to investigate the influence of combustion chamber geometry on spray and combustion characteristics in diesel engine, universal CFD software STAR-CD is applied to simulate the combustion processes in three different types of combustion chambers of diesel engine. The effect of combustion chamber geometry on in–cylinder air motion, temperature field and exhaust emissions are researched in this paper. Comparing with experimental results, calculation models are proved to be validity. The results show that differences of combustion chamber shape change the characteristic of flow field in cylinder, which affects the formation of mixed gas and determines the combustion and emission characteristics.

2018 ◽  
Vol 34 (6) ◽  
pp. 2806-2813
Author(s):  
Pappula Bridjesh ◽  
Pitchaipillai Periyasamy ◽  
Narayanan Kannaiyan Geetha

This experimental investigation is an endeavour to substitute diesel with WPO as fuel on a diesel engine. Enhancing the physiochemical properties of WPO or with hardware modifications on the engine, the performance of engine could not be improved up to the mark. The physiochemical properties of WPO are enhanced by the use of composite additive, which is a mixture of soy lecithin and 2-ethylhexyl nitrate and to improve the in-cylinder air motion; subsequently to increase the swirl and turbulence, standard hemispherical combustion chamber is modified to toroidal spherical grooves combustion chamber. The results of combined effect of modifying the combustion chamber and addition of composite additive suggest that improvements in engine-out emissions can be obtained from current diesel engines by enhancing physiochemical properties of fuel and matching geometry of combustion chamber. Engine combustion and emission characteristics under various loads for various fuels under test are as well studied.


Author(s):  
Yoichi Niki ◽  
Yoshifuru Nitta ◽  
Hidenori Sekiguchi ◽  
Koichi Hirata

This study focuses NH3 as an alternative fuel for internal combustion engines, because NH3 is known as a H2 carrier and its combustion does not produce CO2 causing global warming. On the other hand, some reports show that unburned NH3 and N2O appear in exhaust gas, when NH3 is used as fuel for compression ignition or spark ignition engines. NH3 is toxic and N2O is one of the greenhouse gases. These emissions should not be emitted. These reports point out that exhaust gas after treatments and/or injection strategies can be effective to reduce these emissions. From our previous investigations, it was confirmed that NH3 and N2O were contained in the exhaust gas of a conventional diesel engine with NH3 gas mixed into the engine intake. In this study, NH3 combustion processes in the diesel engine were investigated from the experimental results. Based on the investigations, a pilot or postinjection was conducted to reduce emissions of NH3 and N2O. In this paper, first the experimental results of the combustion and exhaust emission characteristics on the conventional diesel engine with NH3 gas mixed into the engine intake are shown. NH3 and N2O emissions are then verified by analyzing the exhaust gas. Next, NH3 combustion processes in the diesel engine are considered from the experimental results to report on the effects of a pilot and postdiesel fuel injection on NH3 and N2O production processes. The experimental results suggest that the multiple diesel fuel injections would be one of the effective measures to reduce N2O and NH3 emissions on NH3 and diesel dual-fueled engine.


2011 ◽  
Vol 383-390 ◽  
pp. 1431-1440
Author(s):  
Yong Shang ◽  
Fu Shui Liu ◽  
Xiang Rong Li ◽  
Jing Wu

One method of parametric design on combustion chamber is used in this paper. Several independent geometrical parameters of ω type and double swirl combustion chamber are brought forward. Different series of ω type and double swirl combustion chambers have been designed by using this method. The effect of the independent geometrical parameters on the performance of diesel engine has been studied by using CFD code AVL FIRE. According to this method of parametric design and calculation result, two pistons with ω type and double swirl combustion chamber has been designed with the target of the highest indicated heat efficiency. The test result shows that, contrasting with ω type chamber, BSFC and main combustion duration of double swirl combustion chamber is lower by 7.5 and 6.9 percent respectively, while indicated heat efficiency is 7.1 percent higher. And the calculation result has coherence with the experiment. It is proved that the method of parametric design on combustion chamber can satisfy the requirement of designing. At the same time, this method can be extended to design other combustion chambers.


Author(s):  
Ruitao Song ◽  
Gerald Gentz ◽  
Guoming Zhu ◽  
Elisa Toulson ◽  
Harold Schock

A turbulent jet ignition system of a spark ignited (SI) engine consists of pre-combustion and main-combustion chambers, where the combustion in the main-combustion chamber is initiated by turbulent jets of reacting products from the pre-combustion chamber. If the gas exchange and combustion processes are accurately controlled, the highly distributed ignition will enable very fast combustion and improve combustion stability under lean operations, which leads to high thermal efficiency, knock limit extension, and near zero NOx emissions. For model-based control, a precise combustion model is a necessity. This paper presents a control-oriented jet ignition combustion model, which is developed based on simplified fluid dynamics and thermodynamics, and implemented into a dSPACE based real-time hardware-in-the-loop (HIL) simulation environment. The two-zone combustion model is developed to simulate the combustion process in two combustion chambers. Correspondingly, the gas flowing through the orifices between two combustion chambers is divided into burned and unburned gases during the combustion process. The pressure traces measured from a rapid compression machine (RCM), equipped with a jet igniter, are used for initial model validation. The HIL simulation results show a good agreement with the experimental data.


2014 ◽  
Vol 984-985 ◽  
pp. 900-906
Author(s):  
L. Saravanakumar ◽  
B.R. Ramesh Bapu ◽  
B. Durga Prasad

The present work investigates the effect of change in combustion chamber geometry on performance and emission characteristics of single cylinder diesel engine fuelled with mahua biodiesel. Since plant oil derived from the mahua tree has high fatty acids, it undergoes esterification followed by transesterification process to reduce its viscosity. Experiments were conducted using a blend of 20% biodiesel (B20) 40% biodiesel (B40) with diesel and compared with diesel by using two types of combustion chamber geometry, explicitly hemispherical and modified hemispherical combustion chamber. Performance parameters such as Brake Thermal Efficiency (BTE), Brake Specific Fuel Consumption (BSFC) and emission parameters like Unburned Hydro Carbon (UBHC), Oxides of Nitrogen (NOx) were studied from the diesel engine with above mentioned configurations. It is obvious that there is considerable improvement in the performance parameter viz, BTE, BSFC and reduction in UBHC emissions by using the modified geometry piston. However, the NOx emission was found to be higher than that of standard configuration. The results obtained from the blend B20 at modified combustion chamber geometry are on par with diesel and hence mahua biodiesel can be suggested as an alternative fuel for Compression Ignition (C.I) engine with modified combustion chamber geometry.


Author(s):  
Digvijay B. Kulshreshtha ◽  
S. A. Channiwala ◽  
Jatin R. Patel

The combustion chamber of gas turbine unit is one of the most critical components to be designed. The study of literature review reveals that much work is available pertaining to design and performance of combustion chamber. However, the systematic approach and optimized liner wall configuration is not easily traceable in the literature. This is particularly true for small capacity units. Hence there is a need for experimental optimization of combustion chamber in small capacity range. The present work aims at the experimental optimization of liner wall configuration. Four different types of combustion chambers with primary zone equivalence ratios of 0.5, 0.7, 0.9 and 1.1 are designed, developed and experimented based on which an optimal configuration is recommended. It is worth to mention that the present work clearly focuses the combustion chamber with equivalence ratio in primary zone as 0.9 as the optimal combustion chamber.


Author(s):  
A. K. Babu ◽  
G. Devaradjane

The intent of this paper is to summarize the state of knowledge on use of vegetable oils as diesel fuels. Fuel related properties are reviewed and compared with conventional diesel fuel. The use of neat vegetable oil (edible and/or nonedible), biodiesel and its blends in a diesel engine has been discussed. Performance and emission characteristics are highlighted. Suitability of different combustion chambers for diesel engine operation with vegetable oils is outlined. Techniques to decrease viscosities are discussed. An overview on current developments on the use of vegetable oils directly and indirectly in diesel engines is presented.


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