scholarly journals Characterization of Engine Performance, Combustion Process and Emission of Diesel/CNG Dual Fuel Engines with Pilot Injection Timing Variation at Low Load

2019 ◽  
Vol 588 ◽  
pp. 012005 ◽  
Author(s):  
Dori Yuvenda ◽  
Bambang Sudarmanta ◽  
Arif Wahjudi ◽  
Jose da Silva
Keyword(s):  
Combustion Process ◽  
Engine Performance ◽  
Dual Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Low Load ◽  
Dual Fuel Engines

scholarly journals Effect of hydrogen addition in diesel/natural gas dual-fuel combustion with late injection

2021 ◽  
Vol 312 ◽  
pp. 08005
Author(s):  
Antonio Caricato ◽  
Antonio Paolo Carlucci ◽  
Antonio Ficarella ◽  
Luciano Strafella
Keyword(s):  
Natural Gas ◽  
Conversion Efficiency ◽  
Early Stage ◽  
Combustion Process ◽  
Pollutant Emission ◽  
Dual Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Fuel Conversion ◽  
Hydrogen Addition

In a previous work, the effectiveness of late pilot injection on improving combustion behaviour – in terms of fuel conversion efficiency and pollutant emission levels – in a diesel/natural gas dual-fuel engine was assessed. Then, an additional set of experiments was performed, aiming at speeding up the combustion process possibly without penalizing NOx levels. Therefore, hydrogen was added to natural gas in a percentage equal to 10%. Results show that hydrogen addition has a significant effect on the combustion development specially during the early stage of combustion: ignition delay is shortened and combustion centre is advanced, while the combustion duration increases when pilot injection timing is set to conventional values, while remains basically unchanged for late timings. Fuel conversion efficiency is only slightly penalized when hydrogen is added. Moreover, it was confirmed that, in general, combustion strategy with late pilot injection timing does not penalize fuel conversion efficiency; indeed, in some cases, it actually increases. Concerning regulated emission levels, it is again proven that late pilot injection does not penalize pollutant production: the hydrocarbons and carbon monoxide reduce as pilot injection is delayed, probably due to the higher temperatures reached into the cylinder during most part of the expansion stroke. Moreover, adding hydrogen always reduces their levels. Concerning NOx, they are drastically reduced delaying pilot injection; as expected, hydrogen addition promotes NOx formation, but the increase, evident with conventional pilot injection timings, becomes marginal with late injection strategy. Therefore, combustion strategy performance with late pilot injection in dual-fuel diesel/natural gas combustion conditions can be further improved with 10% hydrogen addition to natural gas.

Prediction and optimization of dual-fuel marine engine emissions and performance using combined ANN with PSO algorithms

2021 ◽  
pp. 146808742199047
Author(s):  
Cheng Ma ◽  
Chong Yao ◽  
En-Zhe Song ◽  
Shun-Liang Ding
Keyword(s):  
Neural Network ◽  
Fuel Consumption ◽  
Optimization Design ◽  
Rbf Neural Network ◽  
Engine Performance ◽  
Original Data ◽  
Dual Fuel ◽  
Injection Timing ◽  
Pilot Injection ◽  
Fuel Consumption And Emissions

With the increasingly stringent environmental issues and regulations, there are higher requirements for improving engine performance and reducing pollution. Combining artificial neural network and particle swarm optimization algorithm to optimize the fuel consumption and emissions for micro-ignition dual-fuel engines. A model-based calibration scheme is maintained to reduce the number of experimental points by employing space-filling and V optimization design, to save the experimental cost and improve efficiency. The experimental data used to establish an RBF neural network prediction model that achieves a perfect mapping of engine input and output parameters. Controllable variables such as speed, torque, main injection timing, pilot injection timing, pilot injection quantity, rail pressure, excess air coefficient, and substitution rate limit parameters are input as neural networks. Subsequently, the combination of control parameters was optimized through PSO, thereby to achieve fuel consumption and emissions trade-off. Matching experiment results show actual emissions of NOx, THC, and CO decreased by 20.5%, 30.3%, and 43.1%, respectively, and the BSFC declined by an average of 2.1% contrasted with the original data. It achieves the optimum of emission and fuel consumption at the same time.

3D-CFD Simulation of Diesel and Dual Fuel Engine Combustion

2007 ◽  
Author(s):  
Chengke Liu ◽  
G. A. Karim
Keyword(s):  
Cfd Simulation ◽  
Fuel Injection ◽  
Combustion Process ◽  
Dual Fuel ◽  
Injection Timing ◽  
Combustion Chambers ◽  
Detailed Chemical Kinetics ◽  
Swirl Chamber ◽  
Dual Fuel Engines ◽  
Combustion Processes

A 3D-CFD model with a reduced detailed chemical kinetics of the combustion of diesel and methane fuels is developed while considering turbulence during combustion to simulate the mixture flow, formation and combustion processes within diesel and diesel/methane dual fuel engines having swirl chambers. The combustion characteristics of the pilot injection into a small pre-chamber are also investigated and compared with those within a swirl chamber. Modeling results were validated by a group of corresponding experimental data. The spatial and temporal distributions of the mixture temperature, pressure and velocity under conditions with and without liquid fuel injection and combustion are compared in the swirl and main combustion chambers. The effects of engine speed, injection timing, and the addition of carbon dioxide on the combustion process of dual fuel engines are investigated. It is found that in the absence of any fuel injection and combustion, the swirl center is initially formed at the bottom left of the swirl chamber, and then moved up with continued compression in the top-right direction toward the highest point. The swirling motion within the swirl and main combustion chambers promotes the evaporation of the liquid pilot and the combustion processes of diesel and dual fuel engines. It was observed that an earlier autoignition can be obtained through injecting the pilot fuel into the small prechamber compared to the corresponding swirl chamber operation. It is to be shown that reduced engine emissions and improved thermal efficiency can be achieved by two-stage HCCI combustion.

scholarly journals Potential and Limitations of Dual Fuel Operation of High Speed Large Engines

2016 ◽  
Author(s):  
Christoph Redtenbacher ◽  
Constantin Kiesling ◽  
Maximilian Malin ◽  
Andreas Wimmer ◽  
Jose V. Pastor ◽  
...  
Keyword(s):  
High Speed ◽  
State Of The Art ◽  
Combustion Process ◽  
Engine Performance ◽  
Dual Fuel ◽  
Injection Timing ◽  
Gas Combustion ◽  
Gas Engine ◽  
Pilot Fuel ◽  
Diesel Fractions

Interest is growing in using fully flexible diesel-gas dual fuel engines for power generation and propulsion on land and sea. Benefits such as the flexibility to adapt the type of fuel to the market situation, fail-safe operation and lower NOx emissions than diesel engines are convincing arguments for engine operators. However, diesel-gas engine concepts still suffer from lower efficiency than state-of-the-art monovalent diesel engines and spark ignited gas engines when operated in the corresponding fuel mode. To meet stringent NOx emission legislation, high diesel substitution rates are necessary, which in turn often lead to poor combustion stability. Especially with these small diesel fractions, the challenge remains to ensure stable ignition, fast combustion of the air-fuel mixture and low hydrocarbon emissions. The aim of this paper is to identify and investigate the potential and limitations of diesel-gas combustion concepts for high speed large engines operated in gas mode with very small amounts of pilot fuel (< 5 % diesel fraction1). Experimental tests were carried out on a flexible single cylinder research engine (swept volume approximately 6 1) equipped with a common rail system. Various engine configurations and operating parameters were varied and the effects on the combustion process were analyzed. The results presented in this paper include a comparison of the performance of the investigated dual fuel concept to those of a state-of-the-art monovalent gas engine and a state-of-the-art monovalent diesel engine. Evaluation reveals that certain limiting factors exist that prevent the dual fuel engine from performing as well as the superior gas engine. On the other hand, the potential is already present for the dual fuel concept to compete with the diesel engine. Since the injection of pilot fuel is of major importance for flame initialization and thus for the main combustion event of the dual fuel engine, optical investigations in a spray box, measurements of injection rates and 3D-CFD simulation were conducted to obtain even more detailed insight into these processes. A study on the influence of the diesel fraction shows that diminishing the diesel fraction from 3 % to lower values has a significant impact on engine performance because of the effects of such a reduction on injection, ignition delay and initial flame formation. An investigation of the influence of the injection timing reveals that with diesel fractions of ≤ 1.5 %, the well-known relationship between the injection timing and combustion phasing of conventional engine concepts is no longer valid. The presented results illustrate which operating strategy is beneficial for engine performance in terms of low NOx emissions and high efficiency. Moreover, potential measures can be derived which allow for further optimization of the diesel-gas combustion process.

Three-Dimensional Computational Fluid Simulation of Diesel and Dual Fuel Engine Combustion

2008 ◽  
Vol 131 (1) ◽  
Author(s):  
Chengke Liu ◽  
G. A. Karim
Keyword(s):  
Fuel Injection ◽  
Combustion Process ◽  
Fluid Simulation ◽  
Dual Fuel ◽  
Injection Timing ◽  
Detailed Chemical Kinetics ◽  
Mixture Flow ◽  
Swirl Chamber ◽  
Dual Fuel Engines ◽  
Combustion Processes

A 3D computational fluid dynamics model with a reduced detailed chemical kinetics of the combustion of diesel and methane fuels is developed while considering turbulence during combustion to simulate the mixture flow, formation, and combustion processes within diesel and diesel/methane dual fuel engines having swirl chambers. The combustion characteristics of the pilot injection into a small prechamber are also investigated. Modeled results were validated by a group of corresponding experimental data. The spatial and temporal distributions of the mixture temperature, pressure, and velocity under conditions with and without liquid fuel injection and combustion are compared. The effects of engine speed, injection timing, and the addition of carbon dioxide on the combustion process of dual fuel engines are investigated. It is found that in the absence of any fuel injection and combustion, the swirl center is initially formed at the bottom-left of the swirl chamber, and then moved up with continued compression in the top-right direction toward the highest point. The swirling motion within the swirl and main combustion chambers promotes the evaporation of the liquid pilot and the combustion processes of diesel and dual fuel engines. It was observed that an earlier autoignition can be obtained through injecting the pilot fuel into the small prechamber compared with the corresponding swirl chamber operation. It is to be shown that reduced engine emissions and improved thermal efficiency can be achieved by a two-stage homogenous charge compression ignition combustion.

Sign in / Sign up

Export Citation Format

Share Document