Effect of Water Injection Timing on the Combustion and Emissions of a Direct Injection Gasoline Engine

2021 ◽  
pp. 2001064
Author(s):  
Aqian Li ◽  
Zhaolei Zheng ◽  
Tao Peng
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Water Injection ◽  
Injection Timing ◽  
Effect Of Water ◽  
Direct Injection Gasoline Engine

Analysis of cycle-by-cycle variation in a direct injection gasoline engine using a laser-induced fluorescence technique

2003 ◽  
Vol 4 (2) ◽  
pp. 143-153 ◽  
Author(s):  
T Fujikawa ◽  
Y Nomura ◽  
Y Hattori ◽  
T Kobayashi ◽  
M Kanda
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Mixture Distribution ◽  
Fuel Mixture ◽  
Laser Induced Fluorescence ◽  
Injection Timing ◽  
Indicated Mean Effective Pressure ◽  
Cycle Variation ◽  
Spark Timing ◽  
Direct Injection Gasoline Engine

To analyse the cycle-by-cycle variation of combustion in a direct injection gasoline engine equipped with a fan-shape spray nozzle and operated with exhaust gas recirculation (EGR), the fuel mixture distribution was measured at a time of spark and during the combustion period by the laser-induced fluorescence (LIF) technique. It was found that in the case of advanced or retarded injection timing, the initial combustion period tends to extend and the indicated mean effective pressure (i.m.e.p.) becomes low when lean mixtures appear at the spark position and at the spark timing. This suggests that the cycle-by-cycle variation of combustion under these conditions is dominated by the fuel concentration at the spark position and spark timing. In contrast to this, for the best injection timing, which allows the lowest cycle-by-cycle variation, the i.m.e.p. fluctuation is affected not by the initial combustion period but by the main combustion period. The observation of LIF images revealed that the i.m.e.p. fluctuation at this condition is strongly correlated to the unburned mixture quantity at the side area of the piston cavity during the latter half of the combustion period. It was shown by a computational fluid dynamics (CFD) calculation that the combination of a uniform spray pattern and a compact cavity shape is effective to reduce the over-lean mixture region in the edge of the piston cavity, which is responsible for the cycle-by-cycle variation of combustion at the condition of best-tuned injection timing.

Effect of piston shape design on the scavenging performance and mixture preparation in a two-stroke boosted uniflow scavenged direct injection gasoline engine

2020 ◽  
pp. 146808741990007 ◽  
Author(s):  
Xinyan Wang ◽  
Hua Zhao
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Shape Design ◽  
Injection Timing ◽  
Stoichiometric Mixture ◽  
Split Injection ◽  
Spark Plug ◽  
Direct Injection Gasoline Engine ◽  
Stroke Engine ◽  
Injection Strategies

Compared to a four-stroke engine, the two-stroke engine doubles firing frequency and has favourable power-to-weight or power-to-volume ratio as well as engine downsizing to improve the overall powertrain fuel economy. In order to overcome the shortcomings of the conventional cross-flow or loop scavenged two-stroke engines, a two-stroke boosted uniflow scavenged direct injection gasoline engine was designed and its performance was analysed. In this study, three-dimensional computational fluid dynamics simulations were performed to understand the impact of the piston shape design on the scavenging process, in-cylinder flow formation, turbulence level and subsequent fuel/air mixing process in the boosted uniflow scavenged direct injection gasoline engine. Both single injection and split injection strategies were investigated to study the interactions between piston designs and fuel injection strategies to achieve stoichiometric mixture around the spark plug. The results show that the optimised piston with the same opening timing for all scavenge ports could achieve much better scavenging performance than the baseline piston design. In particular, the shallow pistons, that is, Piston #1 and Piston #4, could produce stoichiometric mixture around the spark plug with relatively lower inhomogeneity and higher turbulence kinetic energy around top dead centre when implementing the split injection strategy with start of injection timing at 250/310 °CA.

Managing controlled auto-ignition combustion by injection on a direct-injection gasoline engine

2007 ◽  
Vol 221 (9) ◽  
pp. 1125-1137 ◽  
Author(s):  
Y Li ◽  
H Zhao ◽  
N Brouzos ◽  
B Leach
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Injection Timing ◽  
Split Injection ◽  
Gasoline Engines ◽  
Auto Ignition ◽  
Direct Injection Gasoline Engine ◽  
Early Closure ◽  
Exhaust Valves ◽  
Early Injection

Controlled auto-ignition (CAI) combustion in gasoline engines has great potential for reducing both NO x emissions and fuel consumption, but its application is still hindered by the lack of direct control of combustion phasing and by the limited CAI operation range. In this paper, the effect of injection timing and split injection on CAI combustion is presented in a single-cylinder direct-injection gasoline engine with an air-assisted injector. The CAI combustion was achieved by trapping some of the burned gases within the cylinder by using low-lift short-duration camshafts and early closure of the exhaust valves. During the experiments, the engine speed was varied from 1200 to 2400 r/min and the air-fuel ratio was altered from stoichiometric to the misfire limit. Both single and split injections were investigated at different injection timings and fuel quantities. The experimental results show that injection timing has an important effect on CAI combustion for single and split injections. Early injection produces faster and more stable combustion, less hydrocarbon and CO emissions, but very rapid heat release rates and higher NO x emissions. The CAI operation range could be extended significantly by early injection. Split injection gives even further extension of the CAI range in both stoichiometric and lean mixture operations. These results indicate that optimizing the injection timing and using split injection is an effective way to control and extend CAI operation in a direct-injection gasoline engine.

Optimization of Mixture Formation of Diesel Fuel in a Small CI Engine: The Effect of Water (H2O) Injection Into Intake Port

2017 ◽  
Author(s):  
Se Hun Min ◽  
Jeonghyun Park ◽  
Hyun Kyu Suh
Keyword(s):  
Water Injection ◽  
Injection Timing ◽  
Intake Port ◽  
Cylinder Pressure ◽  
Test Results ◽  
Analysis Model ◽  
Simultaneous Reduction ◽  
Effect Of Water ◽  
Rate Of Heat Release ◽  
Ci Engine

The objective of this study is to investigate the effect of water injection into intake port on the performance of small CI engine. The ECFM-3Z model was applied for the combustion analysis model, and the amount of injected water were varied 10%, 20% and 30% of injected fuel mass. The results of this work were compared in terms of cylinder pressure, rate of heat release (ROHR), and the ISNO and soot emissions. It was found that the cylinder pressure was decreased from 1.2% to 9.2% when the amount of injected water was increased from 10% to 30%. In the results, NO emission significantly decreased from about 24% to about 85% when the amount of injected water increased due to the specific heat and latent heat of water. Considering the test results, the best conditions for the simultaneous reduction of NO and soot is the BTDC 05deg of injection timing and 30% of water injection mass. It can be expected the best IMEP and ISFC characteristics.

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

2014 ◽  
Vol 532 ◽  
pp. 362-366 ◽  
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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