Modeling and Validation of a Lean Burn Natural Gas Engine

1998 ◽  
Vol 123 (3) ◽  
pp. 425-430 ◽  
Author(s):  
Anupam Gangopadhyay ◽  
Peter Meckl
Keyword(s):  
Natural Gas ◽  
Mean Value ◽  
Intake Manifold ◽  
State Variables ◽  
Lean Burn ◽  
Gas Engine ◽  
Gasoline Engines ◽  
Natural Gas Engine ◽  
Engine Model ◽  
Intake Manifold Pressure

In this paper, a control-oriented model of a medium-duty throttle-body natural gas engine is developed. The natural gas engine uses lean-burn technology without exhaust gas recirculation (EGR). The dynamic engine model differs from models of gasoline engines by including the natural gas fuel dynamics in the intake manifold. The model is based on a mean value concept and has three state variables: intake manifold pressure, fuel fraction in the intake manifold and the engine rotational speed. The resulting model has been validated in steady-state and transient operation over the usual operating range of the engine between 800 rpm and 2600 rpm with air/fuel ratios ranging between 18.0 and 24.0.

scholarly journals The Effect Mechanisms of Intake Manifold Water Injection on the Emissions of a Natural Gas Engine

2021 ◽  
Vol 943 (1) ◽  
pp. 012015
Author(s):  
Qichao Qin ◽  
Youpeng Chen ◽  
Zhuogeng Qin ◽  
Chaoqun Tu
Keyword(s):  
Natural Gas ◽  
Water Injection ◽  
Experimental System ◽  
Intake Manifold ◽  
Combustion Mechanism ◽  
Lean Burn ◽  
Energy Of Combustion ◽  
Oh Groups ◽  
Gas Engine ◽  
Natural Gas Engine

Abstract NOx is the main emission of lean burn natural gas engine (NGE). Water injection (WI) is an effective method to reduce NOx, which has been widely studied in conventional fuel engine. Currently, there are few researches on the application of WI in NGE. The influences of WI on NGE are not clear. In the paper, the effect mechanisms of WI on the emissions of NGE are studied. Based on the thermodynamic properties of water and the combustion mechanism of natural gas, the emissions generation mechanism of NGE with WI was analyzed. According to the experimental system, the effects of intake manifold water injection (IMWI) on the emissions of a lean burn NGE was carried out. The results show that, with WI, the in-cylinder temperature decreased greatly, which effectively inhibited the formation of thermal NO. Water generated a lot of OH groups, which effectively inhibited the formation of rapid NO. At 1800 rpm and 0.92g/s WI rate, NOx is reduced by 70.4%. OH group could effectively promote CO oxidize to CO2. At 1000 rpm and 0.92g/s WI rate, CO is decreased by 22.2%. However, since the decrease of the total activation energy of combustion reaction, the chain breaking reaction increased, resulting in a significant increase in HC. At 800rpm and 0.92g/s WI rate, HC was increased by 11.6%.

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.

A Fundamental Study on Combustion Characteristics in a Pre-Chamber Type Lean Burn Natural Gas Engine

2019 ◽  
Author(s):  
Masashi Tanamura ◽  
Shintaro Nakai ◽  
Mahoko Nakatsuka ◽  
Shota Taki ◽  
Kohei Ozawa ◽  
...  
Keyword(s):  
Natural Gas ◽  
Combustion Characteristics ◽  
Lean Burn ◽  
Fundamental Study ◽  
Gas Engine ◽  
Natural Gas Engine
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