Effect of injection and ignition timing on a hydrogen-lean stratified charge combustion engine

2021 ◽  
pp. 146808742110346
Author(s):  
Sanguk Lee ◽  
Gyeonggon Kim ◽  
Choongsik Bae
Keyword(s):  
Internal Combustion Engines ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Stability ◽  
Transport Sector ◽  
Injection Timing ◽  
Ignition Timing ◽  
Particulate Emission ◽  
Stratified Charge ◽  
Lean Limit

Hydrogen can be used as a fuel for internal combustion engines to realize a carbon-neutral transport society. By extending the lean limit of spark ignition engines, their efficiency, and emission characteristics can be improved. In this study, stratified charge combustion (SCC) using monofueled hydrogen direct injection was used to extend the lean limit of a spark ignition engine. The injection and ignition timing were varied to examine their effect on the SCC characteristics. An engine experiment was performed in a spray-guided single-cylinder research engine, and the nitrogen oxide and particulate emissions were measured. Depending on the injection timing, two different types of combustion were characterized: mild and hard combustion. The advancement and retardation of the ignition timing resulted in a high and low combustion stability, respectively. The lubricant-based particulate emission was attributed to the in-cylinder temperature and area of the flame surface. Therefore, the results of the study suggest that the optimization of the hydrogen SCC based on the injection and ignition timing could contribute to a clean and efficient transport sector.

scholarly journals Effect of Cylinder-by-Cylinder Variation on Performance and Gaseous Emissions of a PFI Spark Ignition Engine: Experimental and 1D Numerical Study

2021 ◽  
Vol 11 (13) ◽  
pp. 6035
Author(s):  
Luigi Teodosio ◽  
Luca Marchitto ◽  
Cinzia Tornatore ◽  
Fabio Bozza ◽  
Gerardo Valentino
Keyword(s):  
Internal Combustion Engines ◽  
Numerical Study ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Combustion Stability ◽  
Pollutant Emissions ◽  
Gaseous Emissions ◽  
Performance And Emissions ◽  
The Impact

Combustion stability, engine efficiency and emissions in a multi-cylinder spark-ignition internal combustion engines can be improved through the advanced control and optimization of individual cylinder operation. In this work, experimental and numerical analyses were carried out on a twin-cylinder turbocharged port fuel injection (PFI) spark-ignition engine to evaluate the influence of cylinder-by-cylinder variation on performance and pollutant emissions. In a first stage, experimental tests are performed on the engine at different speed/load points and exhaust gas recirculation (EGR) rates, covering operating conditions typical of Worldwide harmonized Light-duty vehicles Test Cycle (WLTC). Measurements highlighted relevant differences in combustion evolution between cylinders, mainly due to non-uniform effective in-cylinder air/fuel ratio. Experimental data are utilized to validate a one-dimensional (1D) engine model, enhanced with user-defined sub-models of turbulence, combustion, heat transfer and noxious emissions. The model shows a satisfactory accuracy in reproducing the combustion evolution in each cylinder and the temperature of exhaust gases at turbine inlet. The pollutant species (HC, CO and NOx) predicted by the model show a good agreement with the ones measured at engine exhaust. Furthermore, the impact of cylinder-by-cylinder variation on gaseous emissions is also satisfactorily reproduced. The novel contribution of present work mainly consists in the extended numerical/experimental analysis on the effects of cylinder-by-cylinder variation on performance and emissions of spark-ignition engines. The proposed numerical methodology represents a valuable tool to support the engine design and calibration, with the aim to improve both performance and emissions.

Effect of Engine Variables on Combustion Performance of Lean Burn Spark Ignition Engine: An Overview

2002 ◽  
Author(s):  
A. Manivannan ◽  
R. Ramprabhu
Keyword(s):  
Internal Combustion Engines ◽  
Flow Characteristics ◽  
Exhaust Emissions ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Stability ◽  
Combustion Engines ◽  
Si Engine ◽  
Lean Burn ◽  
Lean Combustion

In the development of internal combustion engines, there has been a continuous effort to reduce fuel consumption and exhaust emissions. Lean combustion is a preferred concept for reducing exhaust emissions for meeting stringent emission standards. However lean combustion is associated with increased cycle-by-cycle combustion variation due to combustion instability. The combustion stability under lean mixture conditions could be improved through enhancement of flow characteristics. Effect of engine variables on lean combustion of Spark Ignition (SI) engine is presented, including combustion chamber and inlet port configuration, and ignition system. Use of pre-chamber for lean combustion is one of the feasible method to achieve stable ignition and quick flame propagation. This paper highlights and compares status of various research works carried out in the area of lean burn engines. A critical analysis of reported experimental data is presented in order to substantiate use of lean combustion in SI engine.

Thermal efficiency improvement of super-lean burn spark ignition engine by stratified water insulation on piston top surface

2020 ◽  
pp. 146808742090816 ◽  
Author(s):  
Tsuyoshi Nagasawa ◽  
Yuichi Okura ◽  
Ryota Yamada ◽  
Susumu Sato ◽  
Hidenori Kosaka ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Thermal Stratification ◽  
Water Injection ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Injection Timing ◽  
Engine Test ◽  
Ignition Timing ◽  
Lean Burn ◽  
Compression Stroke

In order to improve thermal efficiency of spark ignition engine under super-lean burn conditions (excess air ratio [Formula: see text]), thermal stratification technique by in-cylinder water injection toward piston surface (stratified water insulated combustion architecture), in which low temperature water vapor layer is formed on the surface, is proposed. From the water spray visualization using the optically accessible engine, injected water is distributed near the piston top surface at ignition timing and thermal stratification can be achieved in the case that water injection timing (SOIw) is set at earlier stage of a compression stroke. In addition, heat flux on the piston surface measured at the same time is reduced by water injection. The 0.5-L single-cylinder engine test at λ = 2.0 at a constant ignition timing also shows that water injection at earlier stage of a compression stroke makes it possible to mitigate knock without significant increase in combustion instability. On the other hand, part of water is distributed near the spark plug at ignition timing with the water injection at SOIw = −60 °ATDC, resulting in unstable combustion. In addition, the engine test at λ = 2.0 and water/fuel ratio(W/F) = 18% shows that knock mitigation by water injection enables spark advance and following combustion enhancement. As a result, combustion period becomes short and cooling loss decreases, followed by the 1.0-pt improvement of gross indicated thermal efficiency. Moreover, the engine can be operated at minimum spark advance for best torque by increasing W/F up to 35%. Finally, stratified water insulated combustion architecture concept is applied at λ = 1.9 with a higher compression ratio of 17, showing that water injection at SOIw = −120 °ATDC and W/F = 50% enables minimum spark advance for best torque operation, and remarkably high gross indicated that thermal efficiency of 52.63% can be achieved with a sufficiently low knock level and coefficient of variation of indicated mean effective pressure.

MODELING NANOSECOND-PULSED SPARK DISCHARGE AND FLAME KERNEL EVOLUTION

2021 ◽  
pp. 1-22
Author(s):  
Joohan Kim ◽  
Vyaas Gururajan ◽  
Riccardo Scarcelli ◽  
Sayan Biswas ◽  
Isaac Ekoto
Keyword(s):  
Electrical Discharge ◽  
Internal Combustion Engines ◽  
Initial Conditions ◽  
Fuel Mixture ◽  
Spark Ignition ◽  
Combustion Stability ◽  
Flame Kernel ◽  
Wide Range ◽  
Challenging Environment ◽  
Kernel Growth

Abstract Dilute combustion, either using exhaust gas recirculation or with excess-air, is considered a promising strategy to improve the thermal efficiency of internal combustion engines. However, the dilute air-fuel mixture, especially under intensified turbulence and high-pressure conditions, poses significant challenges for ignitability and combustion stability, which may limit the attainable efficiency benefits. In-depth knowledge of the flame kernel evolution to stabilize ignition and combustion in a challenging environment is crucial for effective engine development and optimization. To date, comprehensive understanding of ignition processes that result in the development of fully predictive ignition models usable by the automotive industry does not yet exist. Spark-ignition consists of a wide range of physics that includes electrical discharge, plasma evolution, joule-heating of gas, and flame kernel initiation and growth into a self-sustainable flame. In this study, an advanced approach is proposed to model spark-ignition energy deposition and flame kernel growth. To decouple the flame kernel growth from the electrical discharge, a nanosecond pulsed high-voltage discharge is used to trigger spark-ignition in an optically accessible small ignition test vessel with a quiescent mixture of air and methane. Initial conditions for the flame kernel, including its thermodynamic state and species composition, are derived from a plasma-chemical equilibrium calculation. The geometric shape and dimension of the kernel are characterized using a multi-dimensional thermal plasma solver. The proposed modeling approach is evaluated using a high-fidelity computational fluid dynamics procedure to compare the simulated flame kernel evolution against flame boundaries from companion schlieren images.

scholarly journals Impact of Simulated Biogas Compositions (CH4 and CO2) on Vibration, Sound Pressure and Performance of a Spark Ignition Engine

Energies ◽  
2021 ◽  
Vol 14 (21) ◽  
pp. 7037
Author(s):  
Donatas Kriaučiūnas ◽  
Tadas Žvirblis ◽  
Kristina Kilikevičienė ◽  
Artūras Kilikevičius ◽  
Jonas Matijošius ◽  
...  
Keyword(s):  
Energy Efficiency ◽  
Negative Correlation ◽  
Internal Combustion Engines ◽  
Fossil Fuels ◽  
Sound Pressure ◽  
Raw Materials ◽  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Positive Correlation

Biogas has increasingly been used as an alternative to fossil fuels in the world due to a number of factors, including the availability of raw materials, extensive resources, relatively cheap production and sufficient energy efficiency in internal combustion engines. Tightening environmental and renewable energy requirements create excellent prospects for biogas (BG) as a fuel. A study was conducted on a 1.6-L spark ignition (SI) engine (HR16DE), testing simulated biogas with different methane and carbon dioxide contents (100CH4, 80CH4_20CO2, 60CH4_40CO2, and 50CH4_50CO2) as fuel. The rate of heat release (ROHR) was calculated for each fuel. Vibration acceleration time, sound pressure and spectrum characteristics were also analyzed. The results of the study revealed which vibration of the engine correlates with combustion intensity, which is directly related to the main measure of engine energy efficiency—break thermal efficiency (BTE). Increasing vibrations have a negative correlation with carbon monoxide (CO) and hydrocarbon (HC) emissions, but a positive correlation with nitrogen oxide (NOx) emissions. Sound pressure also relates to the combustion process, but, in contrast to vibration, had a negative correlation with BTE and NOx, and a positive correlation with emissions of incomplete combustion products (CO, HC).

Computations of Air/Fuel Preparation Process in a Port-Injected Spark-Ignition Engine During Cold-Starting Phase

2004 ◽  
Vol 126 (3) ◽  
pp. 635-644 ◽  
Author(s):  
Yangbing Zeng ◽  
C. F. Lee
Keyword(s):  
Numerical Study ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Injection Timing ◽  
Preparation Process ◽  
Cold Starting ◽  
Wall Film ◽  
Fuel Accumulation ◽  
Target Path ◽  
Good Agreement

A numerical study has been performed of the air/fuel preparation process in a cold-starting port-injected spark-ignition engine. The latest models were implemented for spray impingement and multicomponent vaporization of the droplet and wall film accounting for finite diffusion in the liquid. The infinite diffusion model was found insufficient for predicting vaporization in this engine, and the single-component fuel representation yields results significantly different from those from the multicomponent one. The operating parameters studied included injection timing, swirl, speed, target path, enrichment, and fuel accumulation. In-cylinder measurements were compared and good agreement was achieved. Detailed quantitative analysis of the air/fuel preparation of the engine was reported.

Comparison of Random Forest and Neural Network in Modelling the Performance and Emissions of a Natural Gas Spark Ignition Engine

2021 ◽  
pp. 1-20
Author(s):  
Jinlong Liu ◽  
Qiao Huang ◽  
Christopher Ulishney ◽  
Cosmin E. Dumitrescu
Keyword(s):  
Neural Network ◽  
Random Forest ◽  
Natural Gas ◽  
Internal Combustion Engines ◽  
Engine Performance ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Data Driven ◽  
Ann Model ◽  
Mean Square Errors

Abstract Machine learning (ML) models can accelerate the development of efficient internal combustion engines. This study assessed the feasibility of data-driven methods towards predicting the performance of a diesel engine modified to natural gas spark ignition, based on a limited number of experiments. As the best ML technique cannot be chosen a priori, the applicability of different ML algorithms for such an engine application was evaluated. Specifically, the performance of two widely used ML algorithms, the random forest (RF) and the artificial neural network (ANN), in forecasting engine responses related to in-cylinder combustion phenomena was compared. The results indicated that both algorithms with spark timing, mixture equivalence ratio, and engine speed as model inputs produced acceptable results with respect to predicting engine performance, combustion phasing, and engine-out emissions. Despite requiring more effort in hyperparameter optimization, the ANN model performed better than the RF model, especially for engine emissions, as evidenced by the larger R-squared, smaller root-mean-square errors, and more realistic predictions of the effects of key engine control variables on the engine performance. However, in applications where the combustion behavior knowledge is limited, it is recommended to use a RF model to quickly determine the appropriate number of model inputs. Consequently, using the RF model to define the model structure and then employing the ANN model to improve the model's predictive capability can help to rapidly build data-driven engine combustion models.

The Potential of a Separated Electric Compound Spark Ignition Engine for Hybrid Vehicle Application

2022 ◽  
Author(s):  
Emiliano Pipitone ◽  
Salvatore Caltabellotta
Keyword(s):  
Internal Combustion Engines ◽  
Ambient Pressure ◽  
Spark Ignition ◽  
Hybrid Vehicle ◽  
Spark Ignition Engine ◽  
Pollutant Emissions ◽  
Exhaust Gas ◽  
Engine Fuel ◽  
Generator Unit ◽  
Overall Efficiency

Abstract In-cylinder expansion of internal combustion engines based on Diesel or Otto cycles cannot be completely brought down to ambient pressure, causing a 20% theoretical energy loss. Several systems have been implemented to recover and use this energy such as turbocharging, turbo-mechanical and turbo-electrical compounding, or the implementation of Miller Cycles. In all these cases however, the amount of energy recovered is limited allowing the engine to reach an overall efficiency incremental improvement between 4% and 9%. Implementing an adequately designed expander-generator unit could efficiently recover the unexpanded exhaust gas energy and improve efficiency. In this work, the application of the expander-generator unit to a hybrid propulsion vehicle is considered, where the onboard energy storage receives power produced by an expander-generator, which could hence be employed for vehicle propulsion through an electric drivetrain. Starting from these considerations, a simple but effective modelling approach is used to evaluate the energetic potential of a spark-ignition engine electrically supercharged and equipped with an exhaust gas expander connected to an electric generator. The overall efficiency was compared to a reference turbocharged engine within a hybrid vehicle architecture. It was found that, if adequately recovered, the unexpanded gas energy could reduce engine fuel consumption and related pollutant emissions by 4% to 12%, depending on overall power output.

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