Development of a Mercedes-Benz Natural Gas Engine M 366 LAG, with a Lean Burn Combustion System

1996 ◽  
Author(s):  
Luiz Henrique Borges ◽  
Carlos Hollnagel ◽  
Wilson Muraro
2018 ◽  
Vol 28 (10) ◽  
pp. 1850124
Author(s):  
Li-Yuan Wang ◽  
Li-Ping Yang ◽  
En-Zhe Song ◽  
Chong Yao ◽  
Xiu-Zhen Ma

The combustion instabilities in a lean-burn natural gas engine have been studied. Using statistical analysis, phase-space reconstruction, and wavelet transforms, the effect of port gas injection on the dynamics of the indicated mean effective pressure (IMEP) fluctuations have been examined at a speed of 800[Formula: see text]rpm and engine load rates of 25% and 50%. The excessive air coefficient is 1.6 for each engine load, and the port gas injection timing (PGIT) ranges from 1 to 120 degrees of crankshaft angle ([Formula: see text]CA) after top dead center (ATDC) of the intake process. The results show that the PGIT has a significant effect on cyclic combustion fluctuations and the dynamics of the combustion system for all studied engine loads. An unreasonable PGIT leads to increased combustion fluctuations, and loosened and bifurcated structures of combustion system attractors. Furthermore, for both low and medium engine loads, the IMEP time series at earlier gas injections ([Formula: see text]CA and [Formula: see text]CA ATDC) undergoes low-frequency fluctuation together with high-frequency fluctuations in an intermittent fashion. For other PGITs, high-frequency intermittent fluctuations become persistent combined with weak low-frequency oscillations. Our results can be used to understand the oscillation characteristics and the complex dynamics of combustion system in a lean-burn natural gas engine. In addition, they may also be beneficial to the development of more sophisticated engine control strategies.


2017 ◽  
Author(s):  
Qian xiong ◽  
Yasuo Moriyoshi ◽  
Koji Morikawa ◽  
Yasushi takahashi ◽  
Tatsuya Kuboyama ◽  
...  

Author(s):  
C R Stone ◽  
K J S Mentis ◽  
M Daragheh

Natural gas is an alternative fuel that has potential for low emissions and a high efficiency. This paper presents the experimental results and predictions from a computer simulation of a fast burn high compression ratio (FBHCR) combustion system intended for use in a lean burn natural gas engine. Comparisons are made between the FBHCR combustion system at two compression ratios, predictions made by a two-zone combustion model and measurements from the original combustion system, for the brake efficiency, brake mean effective pressure, maximum cylinder pressure and the brake specific NOx emissions. Experimental measurements of the unburnt hydrocarbon emissions, the burn duration and the cycle-by-cycle variations in combustion are also discussed from the original and fast burn combustion systems. The results show how the conflicting aims of low emissions and low fuel consumption can be satisfied using a lean burn combustion system. The computer predictions are shown to be reliable, and thus suitable for estimating the performance of other engine builds.


2020 ◽  
pp. 146808742097775
Author(s):  
Ziqing Zhao ◽  
Zhi Wang ◽  
Yunliang Qi ◽  
Kaiyuan Cai ◽  
Fubai Li

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.


Author(s):  
K J S Mendis ◽  
C R Stone ◽  
N Ladommatos ◽  
M Daragheh

This paper presents the rationale behind a fast burn high compression ratio (FBHCR) combustion system intended for use in a lean burn natural gas engine. Comparisons are made between the FBHCR combustion system, predictions made by a two-zone combustion model and measurements from the original combustion system, for the brake efficiency, brake mean effective pressure and the brake specific NOx emissions. Experimental measurements of the unburnt hydrocarbon emissions, the burn duration and the cycle-by-cycle variations in combustion are also discussed from the two combustion systems. The results show how the conflicting aims of low emissions and low fuel consumption can be satisfied by using a lean burn combustion system. A comparison is also made between the following ways of expressing the exhaust emissions: volumetric, brake specific, mass per megajoule of fuel and gravimetric referenced to a specified oxygen level.


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