scholarly journals Knocking characteristics of a high pressure direct injection natural gas engine operating in stratified combustion mode

Open Physics ◽  
2021 ◽  
Vol 19 (1) ◽  
pp. 534-538
Author(s):  
Qiang Zhang ◽  
Yubo Yang ◽  
Demin Jia ◽  
Menghan Li
Keyword(s):  
Natural Gas ◽  
Direct Injection ◽  
Cylinder Pressure ◽  
Combustion Mode ◽  
Pressure Oscillations ◽  
Gas Engine ◽  
Natural Gas Engines ◽  
Natural Gas Engine ◽  
Combustion Modes ◽  
Stratified Combustion

Abstract Knocking becomes an increasingly important issue in direct injection natural gas engines with the application of new combustion modes. In this article, the knocking characteristics of natural gas engine operating in stratified combustion mode were studied with the aid of cylinder pressure oscillations and combustion parameters. The results indicated that knocking tendency will be stronger when operating in stratified combustion mode. The first to the fourth circumferential modes and the first radial mode are the featured modes for knocking behavior, while knocking is more serious when the duration of 10–50% of total energy released is shorter.

Investigation on the combustion noise of a pilot-ignited direct-injection natural-gas engine

2016 ◽  
Vol 230 (14) ◽  
pp. 1942-1957 ◽  
Author(s):  
Menghan Li ◽  
Qiang Zhang ◽  
Guoxiang Li
Keyword(s):  
Natural Gas ◽  
Direct Injection ◽  
Injection Pressure ◽  
Pressure Level ◽  
Combustion Noise ◽  
Injection Timing ◽  
Cylinder Pressure ◽  
Engine Load ◽  
Gas Engine ◽  
Natural Gas Engine

In this paper, the effects of the injection timing, the injection pressure and the engine load on the combustion noise of a pilot-ignited direct-injection natural-gas engine were explored by analysing the separate components of the in-cylinder pressure. The results suggested that retarding the injection timing and reducing the injection pressure are effective ways of controlling the combustion noise. This can be attributed to the promoted burning rate at advanced injection timings and to the increased injection pressure. However, the effect of the engine load seems to be less obvious, although the resonance pressure level appears to increase with increasing engine load; the estimated combustion noise shows a decreasing tendency.

Soot and combustion models for direct-injection natural gas engines

2020 ◽  
pp. 146808742097801
Author(s):  
Kang Pan ◽  
James Wallace
Keyword(s):  
Kinetic Model ◽  
Natural Gas ◽  
Soot Formation ◽  
Direct Injection ◽  
Emission Characteristics ◽  
Gas Engine ◽  
Glow Plug ◽  
Natural Gas Engines ◽  
Natural Gas Engine ◽  
Soot Model

This paper summarizes the validation of a modified multi-step phenomenological soot model and an enhanced combustion model used for direct-injection natural gas engines. In this study, a modified phenomenological soot model including the key steps for soot formation, such as particle inception and surface growth, was developed in KIVA-3V to replace the empirical model for use in a glow plug assisted natural gas direct-injection engine. The soot model was integrated with a CANTERA based kinetic model, which employs a recently developed low temperature natural gas mechanism to predict the reactions of some important gaseous species involved in the soot formation, such as acetylene and hydroxyl. The simulated in-cylinder flame propagation process induced by a glow plug was compared to the experimental optical images obtained in an engine-like environment. In addition, both the kinetic model and modified soot model were compared with the experimental emission data to validate their reliability for predicting natural gas engine emission characteristics. The engine combustion efficiencies obtained in simulations and experiments were compared as well. The matched results suggest that the computational models can well predict the natural gas combustion and emission characteristics, and will be suitable for investigating the direct-injection natural gas engine technologies.

Optimization of the direct injection natural gas engine under different combustion modes

Fuel ◽  
2020 ◽  
Vol 272 ◽  
pp. 117699
Author(s):  
Jie Liu ◽  
Biao Ma ◽  
Ruiguang Yu ◽  
Qiang Guo
Keyword(s):  
Natural Gas ◽  
Direct Injection ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Combustion Modes

Soot emission prediction in pilot ignited direct injection natural gas engine based on n-heptane/toluene/methane/PAH mechanism

Energy ◽  
2018 ◽  
Vol 163 ◽  
pp. 660-681 ◽  
Author(s):  
Menghan Li ◽  
Qiang Zhang ◽  
Xiaori Liu ◽  
Yuxian Ma ◽  
Qingping Zheng
Keyword(s):  
Natural Gas ◽  
Direct Injection ◽  
Soot Emission ◽  
Gas Engine ◽  
Natural Gas Engine

Railplug Design Optimization to Improve Large-Bore Natural Gas Engine Performance

2005 ◽  
Author(s):  
Hongxun Gao ◽  
Matt J. Hall ◽  
Ofodike A. Ezekoye ◽  
Ron D. Matthews
Keyword(s):  
Natural Gas ◽  
High Energy ◽  
Parameter Study ◽  
Transfer Model ◽  
High Speed Photography ◽  
Discharge Process ◽  
Ignition System ◽  
Gas Engine ◽  
Natural Gas Engines ◽  
Natural Gas Engine

It is a very challenging problem to reliably ignite extremely lean mixtures, especially for the low speed, high load conditions of stationary large-bore natural gas engines. If these engines are to be used for the distributed power generation market, it will require operation with higher boost pressures and even leaner mixtures. Both place greater demands on the ignition system. The railplug is a very promising ignition system for lean burn natural gas engines with its high-energy deposition and high velocity plasma jet. High-speed photography was used to study the discharge process. A heat transfer model is proposed to aid the railplug design. A parameter study was performed both in a constant volume bomb and in an operating natural gas engine to improve and optimize the railplug designs. The engine test results show that the newly designed railplugs can ensure the ignition of very lean natural gas mixtures and extend the lean stability limit significantly. The new railplug designs also improve durability.

Kinetic Study of the Ignition Process of Methane/n-Heptane Fuel Blends under High-Pressure Direct-Injection Natural Gas Engine Conditions

2020 ◽  
Vol 34 (11) ◽  
pp. 14796-14813
Author(s):  
Jingrui Li ◽  
Xinlei Liu ◽  
Haifeng Liu ◽  
Ying Ye ◽  
Hu Wang ◽  
...  
Keyword(s):  
High Pressure ◽  
Natural Gas ◽  
Kinetic Study ◽  
Direct Injection ◽  
Ignition Process ◽  
Gas Engine ◽  
Natural Gas Engine ◽  
Fuel Blends

Experimental study of combustion strategy for jet ignition on a natural gas engine

2020 ◽  
pp. 146808742097775
Author(s):  
Ziqing Zhao ◽  
Zhi Wang ◽  
Yunliang Qi ◽  
Kaiyuan Cai ◽  
Fubai Li
Keyword(s):  
Experimental Study ◽  
Natural Gas ◽  
Efficient Points ◽  
Lean Burn ◽  
Gas Engine ◽  
Absolute Value ◽  
Natural Gas Engines ◽  
Natural Gas Engine ◽  
Excess Air ◽  
Lean Limit

To explore a suitable combustion strategy for natural gas engines using jet ignition, lean burn with air dilution, stoichiometric burn with EGR dilution and lean burn with EGR dilution were investigated in a single-cylinder natural gas engine, and the performances of two kinds of jet ignition technology, passive jet ignition (PJI) and active jet ignition (AJI), were compared. In the study of lean burn with air dilution strategy, the results showed that AJI could extend the lean limit of excess air ratio (λ) to 2.1, which was significantly higher than PJI’s 1.6. In addition, the highest indicated thermal efficiency (ITE) of AJI was shown 2% (in absolute value) more than that of PJI. Although a decrease of NOx emission was observed with increasing λ in the air dilution strategy, THC and CO emissions increased. Stoichiometric burn with EGR was proved to be less effective, which can only be applied in a limited operation range and had less flexibility. However, in contrast to the strategy of stoichiometric burn with EGR, the strategy of lean burn with EGR showed a much better applicability, and the highest ITE could achieve 45%, which was even higher than that of lean burn with air dilution. Compared with the most efficient points of lean burn with pure air dilution, the lean burn with EGR dilution could reduce 78% THC under IMEP = 1.2 MPa and 12% CO under IMEP = 0.4 MPa. From an overall view of the combustion and emission performances under both low and high loads, the optimum λ would be from 1.4 to 1.6 for the strategy of lean burn with EGR dilution.

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