Combustion characteristics and particulate emission in a natural-gas direct-injection engine: Effects of the injection timing and the spark timing

This paper discusses the combustion characteristics of CNG under lean and stochiometric conditions in a direct injection engine. The experiments were carried out on a dedicated CNG-Direct Injection engine with 14:1 compression ratio. Combustion characteristics of CNG have been investigated on various injection timings. Injection timing of the fuel injection timing had significant effects on the engine performance, combustion and emissions. The effects became more significant when injection timing was retarded. Injection timing was set after the closing of intake valve and experiments are conducted at 0% and 50% load conditions. Lean stratified operation experiences faster combustion compared to that of stochiometric. In lean stratified operation, there were fast burn rates at the initial stage and slower burning at the later stage. Whereas in stochiometric conditions there is a slightly slower burn at the initial stage and a moderately faster burn at the later stage. The faster initial combustion in lean stratified operation might be due to rapid burn of the initial mixture due to higher turbulence, while a slower burn in the later stage due to diffusion. In contrary to that in stochiometric operations the initial burn is slightly slower, due to moderately strong turbulence and a faster burn due to moderately proceeding mixture. Thus the main effect of fuel injection timing can be explained by the fuel air mixing and the turbulence produced.

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Combustion Characteristics of a Direct-Injection Engine Fueled with Natural Gas−Hydrogen Mixtures

Energy & Fuels ◽

10.1021/ef0502453 ◽

2006 ◽

Vol 20 (2) ◽

pp. 540-546 ◽

Cited By ~ 39

Author(s):

Zuohua Huang ◽

Jinhua Wang ◽

Bing Liu ◽

Ke Zeng ◽

Jinrong Yu ◽

...

Keyword(s):

Natural Gas ◽

Direct Injection ◽

Combustion Characteristics ◽

Direct Injection Engine ◽

Hydrogen Mixtures

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Combustion Characteristics of Methane Direct Injection Engine Under Various Injection Timings and Injection Pressures

ASME 2016 Internal Combustion Engine Fall Technical Conference ◽

10.1115/icef2016-9437 ◽

2016 ◽

Author(s):

Jingeun Song ◽

Mingi Choi ◽

Daesik Kim ◽

Sungwook Park

Keyword(s):

Fuel Injection ◽

Direct Injection ◽

Injection Pressure ◽

Combustion Characteristics ◽

Injection Timing ◽

Direct Injection Engine ◽

Optical Engine ◽

Start Of Injection ◽

Crank Angle ◽

Injection Pressures

The performance of a methane direct injection engine was investigated under various fuel injection timings and injection pressures. A single-cylinder optical engine was used to acquire in-cylinder pressure data and flame images. An outward-opening injector was installed at the center of the cylinder head. Experimental results showed that the combustion characteristics were strongly influenced by the end of injection timing rather than the start of injection timing. Late injection enhanced the combustion speed because the short duration between the end of injection and the spark induced strong turbulence. The flame propagation speeds under various injection timings were directly compared using crank-angle-resolved sequential flame images. The injection pressure was not an important factor in the combustion; the three injection pressure cases of 0.5, 0.8, and 1.1 MPa yielded similar combustion trends. In the cases of late injection, the injection timings of which were near the Intake Valve Closing (IVC) timing, the volumetric efficiency was higher (by 4%) than in the earlier injection cases. This result implies that the methane direct injection engine can achieve higher torque by means of the late injection strategy.

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Parametric study on effects of excess air/fuel ratio, spark timing, and methanol injection timing on combustion characteristics and performance of natural gas/methanol dual-fuel engine at low loads

Energy Conversion and Management ◽

10.1016/j.enconman.2020.112742 ◽

2020 ◽

Vol 210 ◽

pp. 112742 ◽

Cited By ~ 24

Author(s):

Zhanming Chen ◽

Hao Chen ◽

Long Wang ◽

Limin Geng ◽

Ke Zeng

Keyword(s):

Natural Gas ◽

Parametric Study ◽

Combustion Characteristics ◽

Dual Fuel ◽

Injection Timing ◽

Fuel Ratio ◽

Excess Air ◽

Spark Timing ◽

And Performance

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Effect of Injection Timing on Combustion Characteristics of a DI Diesel Engine Fuelled with Pistacia chinensis Bunge Seed Biodiesel

Advanced Materials Research ◽

10.4028/www.scientific.net/amr.614-615.337 ◽

2012 ◽

Vol 614-615 ◽

pp. 337-342

Author(s):

Li Luo ◽

Bin Xu ◽

Zhi Hao Ma ◽

Jian Wu ◽

Ming Li

Keyword(s):

Combustion Temperature ◽

Fuel Injection ◽

Direct Injection ◽

Combustion Characteristics ◽

Injection Timing ◽

Brake Specific Fuel Consumption ◽

Cylinder Pressure ◽

Combustion Duration ◽

Di Diesel Engine ◽

Maximum Combustion Temperature

In this study, the effect of injection timing on combustion characteristics of a direct injection, electronically controlled, high pressure, common rail, turbocharged and intercooled engine fuelled with different pistacia chinensis bunge seed biodiesel/diesel blends has been experimentally investigated. The results indicated that brake specific fuel consumption reduces with the increasing of fuel injection advance angle and enhances with the increasing of biodiesel content in the blends. The peak of cylinder pressure and maximum combustion temperature increase evidently with the increment of fuel injection advance angle. However, the combustion of biodiesel blends starts earlier than diesel at the same fuel injection advance angle. At both conditions, the combustion duration and the peak of heat release rate are insensitive to the changing of injection timing.

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The Research of Lean Combustion Characteristic of Compound Injection System of Direct Injection Engine

Applied Mechanics and Materials ◽

10.4028/www.scientific.net/amm.532.362 ◽

2014 ◽

Vol 532 ◽

pp. 362-366 ◽

Cited By ~ 5

Author(s):

Jiang Feng Mou ◽

Rui Qing Chen ◽

Yi Wei Lu

Keyword(s):

Gasoline Engine ◽

Direct Injection ◽

Injection System ◽

Intake Manifold ◽

Combustion Characteristic ◽

Injection Timing ◽

Mixed Gas ◽

Lean Burn ◽

Direct Injection Engine ◽

Lean Combustion

This paper studies the lean burn limit characteristic of the compound injection system of the direct-injection gasoline engine. The low pressure nozzle on the intake manifold can achieve quality homogeneous lean mixture, and the direct injection in the cylinder can realized the dense mixture gas near the spark plug. By adjusting the two injection timing and injection quantity, and a strong intake tumble flow with special shaped combustion chamber, it can produces the reverse tumble to form different hierarchical levels of mixed gas in the cylinder. Experimental results show: the compound combustion system to the original direct-injection engine lean burn limit raise 1.8-2.5 AFR unit.

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