scholarly journals Numerical and Experimental Investigation of Combustion and Knock in a Dual Fuel Gas/Diesel Compression Ignition Engine

2012 ◽  
Vol 2012 ◽  
pp. 1-10 ◽  
Author(s):  
A. Gharehghani ◽  
S. M. Mirsalim ◽  
S. A. Jazayeri

Conventional compression ignition engines can easily be converted to a dual fuel mode of operation using natural gas as main fuel and diesel oil injection as pilot to initiate the combustion. At the same time, it is possible to increase the output power by increasing the diesel oil percentage. A detailed performance and combustion characteristic analysis of a heavy duty diesel engine has been studied in dual fuel mode of operation where natural gas is used as the main fuel and diesel oil as pilot. The influence of intake pressure and temperature on knock occurrence and the effects of initial swirl ratio on heat release rate, temperature-pressure and emission levels have been investigated in this study. It is shown that an increase in the initial swirl ratio lengthens the delay period for auto-ignition and extends the combustion period while it reduces NOx. There is an optimum value of the initial swirl ratio for a certain mixture intake temperature and pressure conditions that can achieve high thermal efficiency and low NOxemissions while decreases the tendency to knock. Simultaneous increase of intake pressure and initial swirl ratio could be the solution to power loss and knock in dual fuel engine.

Author(s):  
A. Gharehghani ◽  
A. Jazayeri ◽  
M. Mirsalim ◽  
M. Ghanbari

Conventional compression ignition internal combustion engines can easily be converted to a dual fuel mode of operation using natural gas as the main fuel and diesel oil injection as pilot to initiate the mixture or as a part of main fuel to improve the power output by changing the percentage of diesel oil to natural gas. Natural gas is abundant and relatively cheap alternative fuel with capability of reducing emission levels considerably. In order to examine the combustion characteristic of a heavy duty diesel engine which is locally produced, called D87, in dual fuel mode of operation. A detail performance analysis has been carried out where the main fuel is natural gas and diesel oil is as pilot injection. A reduced detailed chemical kinetics combustion model is combined with a partially stirred combustion model which is inserted in KIVA3V2 code to predict the knock and performance characteristics of the engine. Also, interaction between fuels during the combustion has been studied. Influence of parameters such as intake pressure and temperature on occurrence of knock and the effect of initial swirl ratio on engine performance parameters such in cylinder heat release rate, temperature-pressure and emission levels have been investigated. Appropriate computational grid for KIVA has been generated by ANSYS ICEM CFD commercial software. The developed model results are compared and validated with experimental results available during development tests.


Transport ◽  
2015 ◽  
Vol 30 (2) ◽  
pp. 162-171 ◽  
Author(s):  
Maciej Mikulski ◽  
Sławomir Wierzbicki

Currently, one of the major trends in the research of contemporary combustion engines involves the potential use of alternative fuels. Considerable attention has been devoted to methane, which is the main component of Natural Gas (NG) and can also be obtained by purification of biogas. In compression-ignition engines fired with methane or Compressed Natural Gas (CNG), it is necessary to apply a dual-fuel feeding system. This paper presents the effect of the proportion of CNG in a fuel dose on the process of combustion. The recorded time series of pressure in a combustion chamber was used to determine the repeatability of the combustion process and the change of fuel compression-ignition delay in the combustion chamber. It has been showed that NG does not burn completely in a dual-fuel engine. The best conditions for combustion are ensured with higher concentrations of gaseous fuel. NG ignition does not take place simultaneously with diesel oil ignition. Moreover, if a divided dose of diesel is injected, NG ignition probably takes place at two points, as diesel oil.


Author(s):  
N. T. Shoemaker ◽  
C. M. Gibson ◽  
A. C. Polk ◽  
S. R. Krishnan ◽  
K. K. Srinivasan

Different combustion strategies and fuel sources are needed to deal with increasing fuel efficiency demands and emission restrictions. One possible strategy is dual fueling using readily available resources. Propane and natural gas are readily available with the current infrastructure and biodiesel is growing in popularity as a renewable fuel. This paper presents experimental results from dual fuel combustion of methane (as a surrogate for natural gas) and propane as primary fuels with biodiesel pilots in a 1.9 liter, turbocharged, 4-cylinder compression ignition engine at 1800 rev/min. Experiments were performed with different percentage energy substitutions (PES) of propane and methane and at different brake mean effective pressures (BMEP/bmep). Brake thermal efficiency (BTE) and emissions (NOx, HC, CO, CO2, O2 and smoke) were also measured. Maximum PES levels for B100-methane dual fueling were limited to 70% at 2.5 bars bmep and 48% at 10 bars bmep, and corresponding values for B100-propane dual fueling were 64% and 43%, respectively. Maximum PES was limited by misfire at 2.5 bars bmep and the onset of engine knock at 10 bars bmep. Dual fuel BTEs approached straight B100 values at 10 bars bmep while they were significantly lower than B100 values at 2.5 bars bmep. In general, dual fueling was beneficial in reducing NOx and smoke emissions by 33% and 50%, respectively, from baseline B100 levels; however, both CO and THC emissions were significantly higher than baseline B100 levels at all PES and loads.


2015 ◽  
Vol 2015.90 (0) ◽  
pp. 287
Author(s):  
Yushi DAITO ◽  
Atsuki YOSHIOKA ◽  
Takuji ISHIYAMA ◽  
Takahiro SAKO ◽  
Hiroki TANAKA

Author(s):  
Liu Shenghua ◽  
Wang Ziyan ◽  
Ren Jiang

A natural gas and diesel dual-fuel turbocharged compression ignition (CI) engine is developed to reduce emissions of a heavy-duty diesel engine. The compressed natural gas (CNG) pressure regulator is specially designed to feed back the boost pressure to simplify the fuel metering system. The natural gas bypass improves the engine response to acceleration. The modes of diesel injection are set according to the engine operating conditions. The application of honeycomb mixers changes the flowrate shape of natural gas and reduces hydrocarbon (HC) emission under low-load and lowspeed conditions. The cylinder pressures of a CI engine fuelled with diesel and dual fuel are analysed. The introduction of natural gas makes the ignition delay change with engine load. Under the same operating conditions, the emissions of smoke and NOx from the dual-fuel engine are both reduced. The HC and CO emissions for the dual-fuel engine remain within the range of regulation.


2021 ◽  
Vol 7 ◽  
Author(s):  
Hongsheng Guo ◽  
Hailin Li ◽  
Lino Guzzella ◽  
Masahiro Shioji

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