scholarly journals Improving the effective efficiency of a spark ignition engine through the use of a fully independent valve control system

2021 ◽  
Author(s):  
Zbigniew Żmudka ◽  
Stefan Postrzednik
Keyword(s):  
Charge Exchange ◽  
Spark Ignition Engine ◽  
Theoretical Research ◽  
Si Engine ◽  
Load Range ◽  
Engine Operation ◽  
Engine Load ◽  
Effective Work ◽  
Partial Load ◽  
Valve Control

The article presents theoretical research of the proposed system of fully independent valve control (FIVC) of the SI engine. The analysis included controlling the movement of the intake valves, which results in adjusting the mass of the fresh charge to the current engine load, as well as the movement of the exhaust valves, where the main aim is to keep the rest of the exhaust gas in the cylinder, i.e. implementation of internal EGR. The open theoretical Seiliger-Sabathe cycle with the classic throttle regulation of load is the reference cycle for assessment of benefits and study of the effectiveness of obtaining work as a result of application of the FIVC system. A comparative analysis of the effectiveness of application of the proposed system was carried out based on the selected quantities: fuel dose, cycle work, relative work of charge exchange and cycle efficiency. The use of the FIVC to regulate the SI engine load makes it possible to eliminate the throttle and thus reduce the charge exchange work, especially in the partial load range. And this then leads to an increase in internal and effective work, which in turn results in an increase in the effective energy efficiency of an engine operation.

scholarly journals Realization of the Atkinson-Miller cycle in spark-ignition engine by means of the fully variable inlet valve control system

2014 ◽  
Vol 35 (3) ◽  
pp. 191-205 ◽  
Author(s):  
Zbigniew Żmudka ◽  
Stefan Postrzednik ◽  
Grzegorz Przybyła
Keyword(s):  
Charge Exchange ◽  
Flow Resistance ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Miller Cycle ◽  
Inlet Valve ◽  
Engine Operation ◽  
Engine Load ◽  
Part Load ◽  
Valve Control

Abstract The theoretical analysis of the charge exchange process in a spark ignition engine has been presented. This process has significant impact on the effectiveness of engine operation because it is related to the necessity of overcoming the flow resistance, followed by the necessity of doing a work, so-called the charge exchange work. The flow resistance caused by the throttling valve is especially high during the part load operation. The open Atkinson-Miller cycle has been assumed as a model of processes taking place in the engine. Using fully variable inlet valve timing the A-M cycle can be realized according to two systems: system with late inlet valve closing and system with early inlet valve closing. The systems have been analysed individually and comparatively with the open Seiliger-Sabathe cycle which is a theoretical cycle for the classical throttle governing of the engine load. Benefits resulting from application of the systems with independent inlet valve control have been assessed on the basis of the selected parameters: fuel dose, cycle work, charge exchange work and a cycle efficiency. The use of the analysed systems to governing of the SI engine load will enable to eliminate a throttling valve from the system inlet and reduce the charge exchange work, especially within the range of part load operation.

scholarly journals Throttleless control of SI engine load by fully flexible inlet valve actuation system

2016 ◽  
Vol 164 (1) ◽  
pp. 44-48
Author(s):  
Zbigniew ŻMUDKA ◽  
Stefan POSTRZEDNIK ◽  
Grzegorz PRZYBYŁA
Keyword(s):  
Charge Exchange ◽  
Spark Ignition Engine ◽  
Inlet Valve ◽  
Inlet System ◽  
Engine Load ◽  
Actuation System ◽  
Partial Load ◽  
Effective Efficiency ◽  
Cycle Efficiency ◽  
Valve Actuation

A system with independent, early inlet valve closure (EIVC) has been analysed. The open, theoretical cycle has been assumed as a model of processes proceeding in the engine with variable inlet valve actuation. The system has been analysed individually and comparatively with open Seiliger-Sabathe cycle which is theoretical cycle for the classic throttle governing of engine load. The influence of EIVC on fuel economy, cycle work, relative charge exchange work and cycle efficiency has been theoretically investigated. The use of the analysed system to governing of an engine load will enable to eliminate a throttling valve from inlet system and reduce the charge exchange work, especially within the range of partial load. The decrease of the charge exchange work leads to an increase of the internal and effective works, which results in an increase of the effective efficiency of the spark ignition engine.

scholarly journals Experimental Investigation of Using Ethanol-Gasoline in Spark Ignition Engine

2018 ◽  
Vol 21 (3) ◽  
pp. 368-373
Author(s):  
Kadhim Fadhil Nasir
Keyword(s):  
Spark Ignition Engine ◽  
Brake Specific Fuel Consumption ◽  
Si Engine ◽  
Pure Ethanol ◽  
Engine Operation ◽  
Brake Thermal Efficiency ◽  
Brake Power ◽  
Operation Parameter ◽  
Ethanol Addition ◽  
And Performance

The consequence of mixing pure ethanol with gasoline on the pollution and performance of SI engine are investigated experimentally in the existent study. The SI engine that employed in the experiment is a single cylinder four stroke. Analysis is carried out for engine operation parameter, CO2, CO and unburned HC productions. The measurements are recorded for several engine speeds from 1500 – 3000 rpm with load and ethanol addition of (0E, 10E, 20E, 30E, 40E, 50E,). The results displayed increasing in brake power, and brake thermal efficiency while the brake specific fuel consumption decreases when the ethanol- gasoline blends fuel increases. Also it was found that CO, HC, and CO2 concentrations decrease when the ethanol- gasoline increases. The best results obtained in the study is for the blend of E-50.

Thermodynamic analysis of using ethanol-methanol-gasoline (GEM) blends in a turbocharged, spark-ignition engine

2021 ◽  
pp. 1-28
Author(s):  
Hongqing Feng ◽  
Shuwen Xiao ◽  
Zhirong Nan ◽  
Di Wang ◽  
Chaohe Yang
Keyword(s):  
Thermal Efficiency ◽  
Fossil Fuel ◽  
Spark Ignition ◽  
Exergy Efficiency ◽  
Spark Ignition Engine ◽  
Low Carbon ◽  
Si Engine ◽  
Engine Load ◽  
Maximum Value ◽  
Spark Timing

Abstract Low-carbon alcohols have been universally acknowledged as an alternative to fossil fuel in the world, which is environmentally friendly and clean. In this paper, the detailed exergy and energy analysis were carried out on a turbocharged, spark-ignition (SI) engine fueled with methanol-ethanol-gasoline (GEM) under non-knock conditions. The results indicated that increasing the alcohols proportion in blends could slightly improve the exergy efficiency and thermal efficiency and increase the percentage of total irreversibility in the total exergy. The thermal efficiency and exergy efficiency increased to a maximum value and then decreased, while the proportion of total irreversibility in the total exergy increased significantly with the spark timing retarded from the earliest timing. The exergy efficiency and thermal efficiency increased as the engine load increased. Additionally, the total irreversibility increased but the proportion of total irreversibility in the total exergy presented a trend of decreasing as the engine load increased.

A Numerical Simulation of Analysis of Backfiring Phenomena in a Hydrogen-Fueled Spark Ignition Engine

2016 ◽  
Vol 138 (10) ◽  
Author(s):  
K. A. Subramanian ◽  
B. L. Salvi
Keyword(s):  
Greenhouse Gas Emission ◽  
Hot Spot ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Intake Manifold ◽  
Injection Timing ◽  
Si Engine ◽  
Engine Operation ◽  
Study Results ◽  
Residual Gas

Hydrogen utilization in spark ignition (SI) engines could reduce urban pollution including particulate matter as well as greenhouse gas emission. However, backfiring, which is an undesirable combustion process of intake charge in hydrogen-fueled SI engine with manifold-based injection, is one of the major technical issues in view of safety of engine operation. Backfiring occurs generally during suction stroke as the hydrogen–air charge interacts with residual gas, resulting in flame growth and propagation toward upstream of engine's intake manifold, resulting in stalling of engine operation and high risk of safety. This work is aimed at analysis of backfiring in a hydrogen-fueled SI engine. The results indicate that backfiring is mainly function of residual gas temperature, start of hydrogen injection timing, and equivalence ratio. Any hot-spot present in the cylinder would act as ignition source resulting in more chances of backfiring. In addition to this, computational fluid dynamics (CFD) analysis was carried out in order to assess flow characteristics of hydrogen and air during suction stroke in intake manifold. Furthermore, numerical analysis of intake charge velocity, flame speed (deflagration), and flame propagation (backfiring) toward upstream of intake manifold was also carried out. Some notable points of backfiring control strategy including exhaust gas recirculation (EGR) and retarded (late) hydrogen injection timing are emerged from this study for minimizing chance of backfiring. This study results are useful for development of dedicated SI engine for hydrogen fuel in the aspects of elimination of backfiring.

scholarly journals The evaluation of the regularity of the combustion process in the SI engine fueled with petrol and ethanol

2017 ◽  
Vol 168 (1) ◽  
pp. 94-99
Author(s):  
Zdzisław STELMASIAK ◽  
Dariusz PIETRAS
Keyword(s):  
Ethyl Alcohol ◽  
Research Work ◽  
Combustion Process ◽  
Spark Ignition Engine ◽  
Dual Fuel ◽  
Performance Parameters ◽  
Si Engine ◽  
Inlet Valve ◽  
Engine Operation ◽  
The Subject

In the paper are presented results of a research work concerning automotive spark ignition engine fueled with ethyl alcohol. The research was performed on a Fiat 1100 MPI engine adapted to dual fuel feeding. Injection of ethyl alcohol was accomplished in area near inlet valve with use of original injectors, the same as used in case of gasoline feeding. The subject-matter of the study was to compare smoothness of engine operation fueled with alcohol in relation to parameters of the engine fueled traditionally with gasoline. There were analyzed combustion parameters calculated on the basis of recorded indicated diagrams of successive individual combustion cycles and averaged diagrams of successive 50 cycles. Performed investigations are pointing at smooth engine operation running on neat alcohol, and on improvement of performance parameters such as effective power and overall efficiency.

Studying the effects of hydrogen addition on the second-law balance of a biogas-fuelled spark ignition engine by use of a quasi-dimensional multi-zone combustion model

2008 ◽  
Vol 222 (11) ◽  
pp. 2249-2268 ◽  
Author(s):  
C D Rakopoulos ◽  
C N Michos ◽  
E G Giakoumis
Keyword(s):  
Combustion Process ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Combustion Model ◽  
Second Law ◽  
Si Engine ◽  
Engine Operation ◽  
Hydrogen Addition ◽  
Cycle Simulation ◽  
Hydrogen Enrichment

Although a first-law analysis can show the improvement that hydrogen addition impacts on the performance of a biogas-fuelled spark-ignition (SI) engine, additional benefits can be revealed when the second law of thermodynamics is brought into perspective. It is theoretically expected that hydrogen enrichment in biogas can increase the second-law efficiency of engine operation by reducing the combustion-generated irreversibilities, because of the fundamental differences in the mechanism of entropy generation between hydrogen and traditional hydrocarbon combustion. In this study, an experimentally validated closed-cycle simulation code, incorporating a quasi-dimensional multi-zone combustion model that is based on the combination of turbulent entrainment theory and flame stretch concepts for the prediction of burning rates, is further extended to include second-law analysis for the purpose of quantifying the respective improvements. The analysis is applied for a single-cylinder homogeneous charge SI engine, fuelled with biogas—hydrogen blends, with up to 15 vol% hydrogen in the fuel mixture, when operated at 1500r/min, wide-open throttle, fuel-to-air equivalence ratio of 0.9, and ignition timing of 20° crank angle before top dead centre. Among the major findings derived from the second-law balance during the closed part of the engine cycle is the increase in the second-law efficiency from 40.85 per cent to 42.41 per cent with hydrogen addition, accompanied by a simultaneous decrease in the combustion irreversibilities from 18.25 per cent to 17.18 per cent of the total availability of the charge at inlet valve closing. It is also illustrated how both the increase in the combustion temperatures and the decrease in the combustion duration with increasing hydrogen content result in a reduction in the combustion irreversibilities. The degree of thermodynamic perfection of the combustion process from the second-law point of view is quantified by using two (differently defined) combustion exergetic efficiencies, whose maximum values during the combustion process increase with hydrogen enrichment from 49.70 per cent to 53.45 per cent and from 86.01 per cent to 87.33 per cent, respectively.

A Numerical Simulation of Analysis of Backfiring Phenomena in a Hydrogen Fuelled Spark Ignition Engine

2015 ◽  
Author(s):  
K. A. Subramanian ◽  
B. L. Salvi
Keyword(s):  
Hot Spot ◽  
Spark Ignition ◽  
Spark Ignition Engine ◽  
Intake Manifold ◽  
Injection Timing ◽  
Ignition Process ◽  
Si Engine ◽  
Engine Operation ◽  
Study Results ◽  
Residual Gas

Hydrogen utilization in spark ignition engines could reduce urban pollution including particulate matter as well as greenhouse gas (carbon dioxide) emission. However, backfiring, which is an undesirable combustion process of intake charge in hydrogen fuelled spark ignition (SI) engine with manifold based injection, is one of the major technical issues in view of safety as well as continuous engine operation as ignition process could proceed instantaneously due to less ignition energy requirement of hydrogen. Backfiring occurs generally during suction stroke as the hydrogen-air charge interacts with residual gas resulting in flame growth and propagation towards upstream of engine’s intake manifold resulting in stalling of engine operation and high risk of safety. This work is aimed at analysis of backfiring in a hydrogen fuelled SI engine. The results indicate that backfiring is mainly function of residual gas temperature, start of hydrogen injection timing and equivalence ratio. Any hot-spot present in the cylinder would act as ignition source resulting in more chances of backfiring. In addition to this, CFD analysis was carried out in order to assess flow characteristics of hydrogen and air during suction stroke in intake manifold. Furthermore, numerical analysis of intake charge velocity, flame speed (deflagration), and flame propagation (backfiring) towards upstream of intake manifold was also carried out. Some notable points of backfiring control strategy including exhaust gas recirculation (EGR) and retarded (late) hydrogen injection timing are emerged from this study for minimizing chance of backfiring. This study results are useful for development of dedicated spark ignition engine for hydrogen fuel in the aspects of elimination of backfiring.

scholarly journals The use of partial fuel stratification to enable stable ultra-lean deflagration-based Spark-Ignition engine operation with controlled end-gas autoignition of gasoline and E85

2019 ◽  
Vol 21 (9) ◽  
pp. 1678-1695
Author(s):  
Zongjie Hu ◽  
Junjie Zhang ◽  
Magnus Sjöberg ◽  
Wei Zeng
Keyword(s):  
Thermal Efficiency ◽  
Direct Injection ◽  
Spark Ignition ◽  
Combustion Efficiency ◽  
Spark Ignition Engine ◽  
Load Range ◽  
Engine Operation ◽  
Lean Mixture ◽  
Stable Combustion ◽  
Fuel Stratification

Lean operation of Spark-Ignition engines can provide higher thermal efficiency compared to standard stoichiometric operation. However, for a homogeneous lean mixture, the associated reduction of flame speeds becomes an important issue from the perspective of robust ignition and fast flame spread throughout the charge. This study is focused on the use of a lean partial fuel stratification strategy that can stabilize the deflagration, while sufficiently fast combustion is ensured via the use of end-gas autoignition. The engine has a spray-guided Direct-Injection Spark-Ignition combustion system and was fueled with either a high-octane certification gasoline or E85. Partial fuel stratification was achieved using several fuel injections during the intake stroke in combination with a small pilot-injection concurrent with the Spark-Ignition. The results reveal that partial fuel stratification enables very stable combustion, offering higher thermal efficiency for parts of the load range in comparison to well-mixed lean and stoichiometric combustion. The heat release and flame imaging demonstrate that the combustion often has three distinct stages. The combustion of the pilot-injected fuel, ignited by the normal spark, acts as a “super igniter,” ensuring a very repeatable initiation of combustion, and flame incandescence reveals locally rich conditions. The second stage is mainly composed of blue flame propagation in a well-mixed lean mixture. The third stage is the compression autoignition of a well-mixed and typically very lean end-gas. The end-gas autoignition is critical for achieving high combustion efficiency, high thermal efficiency, and stable combustion. Partial fuel stratification enables very effective combustion-phasing control, which is critical for controlling the occurrence and intensity of end-gas autoignition. Comparing the gasoline and E85 fuels, it is noted that achieving end-gas autoignition for the higher octane E85 requires a more aggressive compression of the end-gas via the use of a more advanced combustion phasing or higher intake-air temperature.

scholarly journals Determination of the optimal air-fuel ratio for upgraded biogas engine operation

2021 ◽  
Vol 327 ◽  
pp. 02009
Author(s):  
Radostin Dimitrov ◽  
Penka Zlateva
Keyword(s):  
Combustion Engine ◽  
Three Dimensional ◽  
Spark Ignition Engine ◽  
Engine Fuel ◽  
Load Range ◽  
Engine Operation ◽  
Operating Modes ◽  
Fuel Ratio ◽  
Ratio Variation ◽  
Test Engine

The paper reveals a study about air-fuel ratio variation of spark-ignition engine running on upgraded biogas (biomethane). Using biogas as internal combustion engine fuel and external mixture formation is a new approach to decrease harmful exhaust gas emissions. Тo obtain minimum concentrations of exhaust gases harmful emissions the engine must work with optimal air-fuel ratio. This research contains analysis of many test engine adjusting characteristics to determine optimal air-fuel ratio for each working regime and to obtain maximum effective working process by the use of biomethane as a fuel. Three-dimensional graphics of air-fuel ratio variation across the rpm and load range were made. In conclusion based on performed experiments, a table with values of air-fuel ratio for all engine operating modes and dependence on rpm and load of the engine is proposed.

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