The Experts below are selected from a list of 10173 Experts worldwide ranked by ideXlab platform

Zhaokang Meng - One of the best experts on this subject based on the ideXlab platform.

  • pre injection strategy for pilot diesel compression ignition Natural Gas Engine
    Applied Energy, 2016
    Co-Authors: Min Xu, Wei Cheng, Zhi Li, Hongfei Zhang, Tao An, Zhaokang Meng
    Abstract:

    For pilot fuel compression ignition Natural Gas (CING) Engine, pre-injection strategy of pilot fuel is an important ways to improve Engine performance, emissions and combustion. In this study, effects of pre-injection parameters on combustion and emissions performance were experimentally studied in a pilot diesel CING Engine which was modified from a turbocharged six-cylinder diesel Engine. The cylinder pressure, heart release rate (HRR), start of combustion (SOC), duration of combustion (DOC) and coefficient of variation (COVIMEP), as well as NOx and HC emissions were analyzed. The results indicate that early pre-injection mode leads to lower cylinder pressure and HRR due to decrease of combustion intensity, and thereby lower NOx emission is obtained. In contrast, closely pre-injection timing leads to largely strengthening in combustion which is not beneficial for improving NOx emission performance.

Meng Zhaokang - One of the best experts on this subject based on the ideXlab platform.

  • Pre-injection strategy for pilot diesel compression ignition Natural Gas Engine
    Applied Energy, 2016
    Co-Authors: Xu Min, Cheng Wei, Li Zhi, Zhang Hongfei, An Tao, Meng Zhaokang
    Abstract:

    Abstract For pilot fuel compression ignition Natural Gas (CING) Engine, pre-injection strategy of pilot fuel is an important ways to improve Engine performance, emissions and combustion. In this study, effects of pre-injection parameters on combustion and emissions performance were experimentally studied in a pilot diesel CING Engine which was modified from a turbocharged six-cylinder diesel Engine. The cylinder pressure, heart release rate (HRR), start of combustion (SOC), duration of combustion (DOC) and coefficient of variation (COV IMEP ), as well as NO x and HC emissions were analyzed. The results indicate that early pre-injection mode leads to lower cylinder pressure and HRR due to decrease of combustion intensity, and thereby lower NO x emission is obtained. In contrast, closely pre-injection timing leads to largely strengthening in combustion which is not beneficial for improving NO x emission performance. Furthermore, effects of pre-injection quantity ratio and fuel injection pressure on combustion and emissions of early pre-injection operation modes (on pre-injection timing of 70°CA BTDC) were analyzed. Increase of pre-injection quantity ratio leads to decreasing in ignition intensity which delayed SOC and slowed burning rate of in-cylinder mixture, and thereby leads to lower cylinder pressure and HRR. Due to slowing in in-cylinder combustion, combustion temperature decreased, and hence leads to lower NO x emission and higher HC emission. However, too high pre-injection quantity ratio leads to unstable ignition and even unstable combustion which is not beneficial for Engine performance. Increasing fuel injection pressure leads to larger fraction of premixed quantity of injected fuel which increased ignition energy and leads to rapid combustion, and hence higher cylinder pressure and HRR were obtained. Due to the increase of burning rate of in-cylinder mixture, in-cylinder combustion temperature was increased, and hence leads to higher NO x emission and lower HC emission.

Zuohua Huang - One of the best experts on this subject based on the ideXlab platform.

  • effect of equivalence ratio on combustion and emissions of a dual fuel Natural Gas Engine ignited with diesel
    Applied Thermal Engineering, 2019
    Co-Authors: Jinbao Zheng, Jinhua Wang, Zhibo Zhao, Duidui Wang, Zuohua Huang
    Abstract:

    Abstract China is the world largest Natural Gas Engine market, and the Natural Gas price has a large fluctuation range, Natural Gas-diesel dual-fuel Engine may be one of the options to cope with Gas price fluctuations. Effect of equivalence ratio on combustion and emissions with a low compression ratio of 14.2 in a dual-fuel 6 cylinder Engine was experimentally studied. Comparison between dual-fuel and spark ignition Engine at stoichiometric combustion and same IMEP was conducted. Results show that the Gas consumption rate decreases with the increase of equivalence ratio regardless of the strategy in nozzle parameter, exhaust Gas recirculation (EGR) rate, injection parameter. Peak heat release rate and exhaust Gas temperature increased, and decrease of combustion duration is obtained due to the high equivalence ratio in dual-fuel ignition mode. The Gas consumption rate trend of spark ignition mode is similar to that of dual-fuel Engine with the increase of equivalence ratio. Dual-fuel Engine with low compression ratio of 14.2 run as spark ignition (SI) Gas Engine at stoichiometric ratio, but the difference lies in the combustion process. The peak heat release rate of dual-fuel Engine presents higher value, while the combsution duration of dual-fuel Engine is shorter, and the Gas consumption rate of dual fuel Engine is lower than that of SI Engine.

  • A review of Engine application and fundamental study on turbulent premixed combustion of hydrogen enriched Natural Gas
    Science China-technological Sciences, 2014
    Co-Authors: Jinhua Wang, Meng Zhang, Zuohua Huang
    Abstract:

    The application and fundamental study on turbulent premixed combustion of hydrogen enriched Natural Gas is reviewed in this paper. Discussions include the combustion characteristics of direct injection Engine fueled with hydrogen enriched Natural Gas, visualization study of direct injection combustion of hydrogen enriched Natural Gas using a constant volume vessel, and the fundamental study of turbulent premixed combustion of hydrogen enriched Natural Gas. The effect of additional hydrogen on the combustion process of Natural Gas Engine is investigated from the fundamental view of the interaction between combustion reaction and turbulent flow.

  • combustion characteristics of a direct injection Natural Gas Engine under various fuel injection timings
    Applied Thermal Engineering, 2006
    Co-Authors: Ke Zeng, Zuohua Huang, Bing Liu, Liangxin Liu, Deming Jiang, Yi Ren, Jinhua Wang
    Abstract:

    Abstract The combustion characteristics of a direct-injection Natural Gas Engine under various fuel injection timings were investigated. The results showed that fuel injection timing had a large influence on the Engine performance, combustion and emissions and these influences became largely in the case of late injection. Over-late injection would supply insufficient time for the fuel–air mixing of the late part of the injected fuel, bringing poor quality of mixture formation and subsequently resulting in the slow combustion rate, the long combustion duration and high HC concentration. However, early injection gave a slight influence on both Engine combustion and emissions. There existed an optimum fuel injection timing where the maximum cylinder pressure, the maximum rate of pressure rise and the maximum rate of heat release would get their highest values along with the shortest combustion durations, the shortest heat release duration and more concentrated heat release process closing to the top-dead-centre while maintaining the low level of HC and CO emissions.

Xiaoya Li - One of the best experts on this subject based on the ideXlab platform.

  • Dynamic analysis of the dual-loop Organic Rankine Cycle for waste heat recovery of a Natural Gas Engine
    Energy Conversion and Management, 2017
    Co-Authors: Xuan Wang, Dongzhan Jing, Ge-qun Shu, Hua Tian, Peng Liu, Xiaoya Li
    Abstract:

    Natural Gas internal combustion Engines for electric generating are important primary movers in distributed energy systems. However, more than half of the energy is wasted by exhaust, jacket water and so on. Therefore, it is very meaningful to recover the waste heat, especially the exhaust heat. The DORC (Double loop ORC) is regarded as a suitable way to recover exhaust heat and it can produce electric required by users all the year around. As the waste heat recovery system of the Engine, it often works under different working conditions owing to the varying energy demand of users. However, there is few study on the part-load performance of the DORC under different working conditions. Consequently, the dynamic math model of the DORC for waste heat recovery of a Natural Gas Engine with 1000 kW rated power is established by Simulink in this work. With the PID control of the system, the static performance and dynamic behavior of the DORC under five typical Engine working conditions are simulated and analyzed. Besides, the effects of the mass flow rate of the HT (high temperature) cooling water which is the connection between the two loops on the DORC performance are researched as well. The results illustrate that the DORC can improve the efficiency of the combined system quite well from 100% to 60% Engine working condition, showing good working condition adaptability. Besides, enlarging the mass flow rate of the HT cooling water can enhance the output power of the DORC system, but not very obviously.

Bengt Johansson - One of the best experts on this subject based on the ideXlab platform.

  • investigation of performance and emission characteristics of a heavy duty Natural Gas Engine operated with pre chamber spark plug and dilution with excess air and egr
    SAE International journal of engines, 2012
    Co-Authors: Ashish Shah, Per Tunestal, Bengt Johansson
    Abstract:

    This article deals with application of turbulent jet ignition technique to heavy duty multi-cylinder Natural Gas Engine for mobile application. Pre-chamber spark plugs are identified as a promising means of achieving turbulent jet ignition as they require minimal Engine modification with respect to component packaging in cylinder head and the ignition system. Detailed experiments were performed with a 6 cylinder 9.4 liter turbo-charged Engine equipped with multi-point Gas injection system to compare performance and emissions characteristics of operation with pre-chamber and conventional spark plug. The results indicate that ignition capability is significantly enhanced as flame development angle and combustion duration are reduced by upto 30 % compared to those with conventional spark plugs at certain operating points. Maximum possible dilution (limited by combustion stability index, Coefficient of Variation (COV) of Gross Indicated Mean Effective Pressure (IMEPg)) with excess air and EGR were investigated experimentally at Engine speed of 1500 rpm and 5, 12 and 18 bar IMEPg operating load and results indicate that the lean limit is extended by 0.8-1 Lambda unit and 5-8% EGR rate units. It was also observed that pre-chamber spark plugs cause charge pre-ignition at loads exceeding 10-12 bar IMEPg. To avoid this, the minimum amount of dilution, with excess air and then EGR, which is required to operate above 10 bar IMEPg was estimated experimentally. Finally, to compare performance and emission characteristics of operation with these two ignition techniques, the Engine was tested on an ESC-like (European Stationary Cycle) 12 mode cycle. Results indicated marginal reduction in cycle averaged NOx emissions with maximum excess air dilution and about 50% reduction with maximum EGR dilution, whereas CO and HC emissions increased. Other operating characteristics like the flame development angle, combustion duration, brake efficiency etc. are also compared for the tested operating range of the test Engine. (Less)

  • Hydrogen Addition For Improved Lean Burn Capability of Slow and Fast Burning Natural Gas Combustion Chambers
    SAE Technical Paper Series, 2002
    Co-Authors: Per Tunestal, Bengt Johansson, Magnus Christensen, Patrik Einewall, Tobias Andersson, Owe Jönsson
    Abstract:

    One way to extend the lean burn limit of a Natural Gas Engine is by addition of hydrogen to the primary fuel. This paper presents measurements made on a one cylinder 1.6 liter Natural Gas Engine. Two combustion chambers, one slow and one fast burning, were tested with various amounts of hydrogen (0, 5, 10 and 15 %vol) added to Natural Gas. Three operating points were investigated for each combustion chamber and each hydrogen content level; idle, part load (5 bar IMEP) and 13 bar IMEP (simulated turbocharging). Air/fuel ratio was varied between stoichiometric and the lean limit. For each operating point, a range of ignition timings were tested to find maximum brake torque (MBT) and/or knock. Heat-release rate calculations were made in order to assess the influence of hydrogen addition on burn rate. Addition of hydrogen showed an increase in burn rate for both combustion chambers, resulting in more stable combustion close to the lean limit. This effect was most pronounced for lean operation with the slow combustion chamber.