Experiments and modeling of a dual-mode, turbulent jet ignition engine

2019 ◽  
Vol 21 (6) ◽  
pp. 966-986 ◽  
Author(s):  
Sedigheh Tolou ◽  
Harold Schock
Keyword(s):  
Experimental Data ◽  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Peak Pressure ◽  
Operating Conditions ◽  
Turbulent Jet ◽  
Engine Fuel ◽  
Main Chamber ◽  
Dual Mode ◽  
Ignition System

The dual-mode, turbulent jet ignition system is a promising combustion technology to achieve high diesel-like thermal efficiency at medium to high loads and potentially exceed diesel efficiency at low-load operating conditions. The dual-mode, turbulent jet ignition systems to date proved a high level of improvement in thermal efficiency compared to conventional internal combustion engines. However, some questions were still unanswered. The most frequent question regarded power requirements for delivering air to the pre-chamber of a dual-mode, turbulent jet ignition system. In addition, there was no study available to predict the expected efficiency of a dual-mode, turbulent jet ignition engine in a multi-cylinder configuration. This study, for the first time, predicts the ancillary work requirement to operate the dual-mode, turbulent jet ignition system. It also presents a novel, reduced order, and physics-based model of the dual-mode, turbulent jet ignition engine with a pre-chamber valve assembly. The developed model was calibrated based on experimental data from the Prototype II dual-mode, turbulent jet ignition engine. The simulation results were in good agreement with the experimental data. The validity of the model was observed based on the standard metric of the coefficient of determination as well as comparison plots for in-cylinder pressures. Numerical predictions were compared to experiments for three metrics of main chamber combustion: gross indicated mean effective pressure, main chamber peak pressure, and main chamber phasing for the peak pressure. Predictions were within 5% of experimental data, with one exception of 6%. In addition, the absolute root mean square errors of in-cylinder pressures for both pre- and main-combustion chambers were below 0.35. The calibrated model was further studied to introduce a predictive and generalized model for dual-mode, turbulent jet ignition engines. Such a model can project engine behavior in a multi-cylinder configuration over the entire engine fuel map.

scholarly journals The Influence of Charge Motion on Pre-Chamber and Main Chamber Combustion in a Highly Dilute Jet Ignition Engine

2021 ◽  
Vol 6 ◽  
Author(s):  
Michael Bunce ◽  
Alasdair Cairns ◽  
Sai Krishna Pothuraju Subramanyam ◽  
Nathan Peters ◽  
Hugh Blaxill
Keyword(s):  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
System Optimization ◽  
Combustion Stability ◽  
Main Chamber ◽  
Charge Motion ◽  
Ignition System ◽  
Lean Combustion ◽  
Si Engines ◽  
The Impact

Though there are multiple viable powertrain options available for the automotive sector, those that contain internal combustion engines will continue to account for the majority of global sales for the next several decades. It is therefore imperative to continue the pursuit of novel combustion concepts that produce efficiency levels significantly higher than those of current engines. Introducing high levels of dilution in spark ignited (SI) engines has consistently proven to produce an efficiency benefit compared to conventional stoichiometric engine operation. However, this combustion mode can present challenges for the ignition system. Pre-chamber jet ignition enables stable, highly dilute combustion by both increasing the ignition energy present in the system and distributing it throughout the combustion chamber. Previous work by the authors have shown that jet ignition produces 15–25% increases in thermal efficiency over baseline SI engines with only relatively minor changes to engine architecture. Lean combustion in general and jet ignition in particular represent fundamentally different engine operating modes compared to those of conventional stoichiometric SI engines. Therefore, there are some system sensitivities not present in stoichiometric engines that must be investigated in order to fully optimize the jet ignition system. Differing types and magnitudes of charge motion are incorporated in SI engines to aid with mixture preparation but the influence of charge motion over lean combustion performance, particularly in jet ignition engines, is less well understood. This study analyzes the impact that charge motion has on both pre-chamber and main chamber combustion. A 1.5 L 3-cylinder gasoline engine is outfitted with multiple intake port configurations producing varying magnitudes and types of charge motion. Pre-chamber and main chamber combustion stability and other burn parameter responses are analyzed across multiple speeds and loads, including at critical operating points such as a catalyst heating condition. The results show that there is combustion sensitivity to charge motion, resulting in >1 percentage point spread in peak thermal efficiency for the configurations tested, and that this sensitivity manifests most significantly under low ignitability conditions such as heavy dilution. These results provide guidance for future system optimization of jet ignition engines.

scholarly journals Detailed Experimental Investigation of A Spark Ignition Engine in A Wide Range of Work

2021 ◽  
Vol 1 (1) ◽  
Author(s):  
Melih Yıldız ◽  
Bilge Albayrak Çeper
Keyword(s):  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Heat Dissipation ◽  
Spark Ignition ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Engine Fuel ◽  
Spark Ignition Engines ◽  
Combustion Control ◽  
Wide Range

For years, the goal of vehicle manufacturers; combustion control of spark ignition engines, ease of passage between the various cycles For years, the goal of vehicle manufacturers; combustion control of spark ignition engines, ease of passage between the various cycles, low emission values of diesel engines, high fuel economy and output power, thereby achieving optimum values in internal combustion engines. In this context, to improve the engine performance and increase the volumetric and thermal efficiency of the engine in all operating conditions to minimize the power losses and to reduce the exhaust emissions in order to obtain the maximum power, most economical and without environmental pollution, continues to be updated. In this study, the optimum working map of the engine was obtained by considering the power, torque, specific fuel consumption, cylinder pressure, exhaust gas temperature, thermal efficiency, average effective pressure, heat dissipation rate and emissions of four stroke, two cylinder, spark ignition SI engine fuel.

Thermal efficiency of a dual-mode turbulent jet ignition engine under lean and near-stoichiometric operation

2017 ◽  
Vol 18 (10) ◽  
pp. 1055-1066 ◽  
Author(s):  
Ravi Teja Vedula ◽  
Ruitao Song ◽  
Thomas Stuecken ◽  
Guoming G Zhu ◽  
Harold Schock
Keyword(s):  
Compression Ratio ◽  
Thermal Efficiency ◽  
Equivalence Ratio ◽  
Operating Conditions ◽  
Turbulent Jet ◽  
Combustion Stability ◽  
Effective Pressure ◽  
Dual Mode ◽  
Indicated Mean Effective Pressure ◽  
Combustion Technology

Turbulent jet ignition is a combustion technology that can offer higher thermal efficiency compared to the homogeneous spark ignition engines. A potential combustion-related challenge with turbulent jet ignition is the pre-chamber misfiring due to improperly scavenged combustion residuals and maintaining the mixture composition there. Dual-mode turbulent jet ignition is a novel combustion technology developed to address the aforementioned issues. The dual-mode turbulent jet ignition is an engine combustion technology wherein an auxiliary air supply apart from an auxiliary fuel injection is provided into the pre-chamber. This technology can offer enhanced stoichiometry control and combustion stability in the pre-chamber and subsequently combustion control in the main chamber. In this work, engine testing of a single-cylinder dual-mode turbulent jet ignition engine having a compression ratio of 12.0 was completed with liquid gasoline and the indicated thermal efficiency was measured. High-speed pressure recordings were used to compare and analyze different operating conditions. Coefficient of variation in the indicated mean effective pressure and the global air/fuel equivalence ratio values were used to characterize the engine operation. Lean operating conditions for a global air/fuel equivalence ratio of 1.85 showed an indicated efficiency of 46.8% ± 0.5% at 1500 r/min and 6.0 bar indicated mean effective pressure. In addition, the combustion stability of this engine was tested with nitrogen dilution. The nitrogen diluent fraction was controlled by monitoring the intake oxygen fraction. The dual-mode turbulent jet ignition engine of compression ratio 12.0 delivered an indicated efficiency of 46.6% ± 0.5% under near-stoichiometric operation at 1500 r/min and 7.7 bar indicated mean effective pressure with a coefficient of variation in indicated mean effective pressure of less than 2% for all conditions tested.

Investigating realistic anode off-gas combustion in SOFC/ICE hybrid systems: mini review and experimental evaluation

2021 ◽  
pp. 146808742110583
Author(s):  
Ioannis Nikiforakis ◽  
Zhongnan Ran ◽  
Michael Sprengel ◽  
John Brackett ◽  
Guy Babbit ◽  
...  
Keyword(s):  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Engine Performance ◽  
High Energy ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Case Scenario ◽  
Gas Combustion ◽  
Thermodynamic Conditions ◽  
Decentralized Energy

Solid oxide fuel cells (SOFCs) have been deployed in hybrid decentralized energy systems, in which they are directly coupled to internal combustion engines (ICEs). Prior research indicated that the anode tailgas exiting the SOFC stack should be additionally exploited due to its high energy value, with typical ICE operation favoring hybridization due to matching thermodynamic conditions during operation. Consequently, extensive research has been performed, in which engines are positioned downstream the SOFC subsystem, operating in several modes of combustion, with the most prevalent being homogeneous compression ignition (HCCI) and spark ignition (SI). Experiments were performed in a 3-cylinder ICE operating in the latter modus operandi, where the anode tailgas was assimilated by mixing syngas (H2: 33.9%, CO: 15.6%, CO2: 50.5%) with three different water vapor flowrates in the engine’s intake. While increased vapor content significantly undermined engine performance, brake thermal efficiency (BTE) surpassed 34% in the best case scenario, which outperformed the majority of engines operating under similar operating conditions, as determined from the conducted literature review. Nevertheless, the best performing application was identified operating under HCCI, in which diesel reformates assimilating SOFC anode tailgas, fueled a heavy duty ICE (17:1), and gross indicated thermal efficiency ([Formula: see text]) of 48.8% was achieved, with the same engine exhibiting identical performance when operating in reactivity-controlled compression ignition (RCCI). Overall, emissions in terms of NOx and CO were minimal, especially in SI engines, while unburned hydrocarbons (UHC) were non-existent due to the absence of hydrocarbons in the assessed reformates.

Thermal modelling of modern diesel engines: proposal of a new heat transfer coefficient correlation

2011 ◽  
Vol 225 (11) ◽  
pp. 1544-1560 ◽  
Author(s):  
C A Finol ◽  
K Robinson
Keyword(s):  
Heat Transfer ◽  
Experimental Data ◽  
Heat Transfer Coefficient ◽  
Diesel Engine ◽  
Transfer Coefficient ◽  
Diesel Engines ◽  
Internal Combustion Engines ◽  
Operating Conditions ◽  
Boost Pressure ◽  
Simple Relationship

Existing methods for predicting heat fluxes and temperatures in internal combustion engines, which take the form of correlations to estimate the heat transfer coefficient on the gas-side of the combustion chamber, are based on methodology developed over the past 50 years, often updated in view of more recent experimental data. The application of these methods to modern diesels engines is questionable because key technologies found in current engines did not exist or were not widely used when those methods were developed. Examples of such technologies include: high-pressure common rail and variable fuel injection strategies including retarded injection for nitrogen oxides emission control; exhaust gas re-circulation; high levels of intake boost pressure provided by a single- or double-stage turbocharger and inter-cooling; multiple valves per cylinder and lower swirl; and advanced engine management systems. This suggests a need for improved predicting tools of thermal conditions, specifically temperature and heat flux profiles in the engine block and cylinder head. In this paper a modified correlation to predict the gas-side heat transfer coefficient in diesel engines is presented. The equation proposed is a simple relationship between Nu and Re calibrated to predict the instantaneous spatially averaged heat transfer coefficient at several operating conditions using air as gas in the model. It was derived from the analysis of experimental data obtained in a modern diesel engine and is supported by a research methodology comprising the application of thermodynamic principles and fundamental equations of heat transfer. The results showed that the new correlation adequately predicted the instantaneous coefficient throughout the operating cycle of a high-speed diesel engine. It also estimated the corresponding cycle-averaged heat transfer coefficient within 10 per cent of the experimental value for the operating conditions considered in the analysis.

Adaptive Wiebe Function Parameters for a Port-Fuel Injected Hydrogen-Fueled Engine

2019 ◽  
Author(s):  
Shah Saud Alam ◽  
Christopher Depcik
Keyword(s):  
Experimental Data ◽  
Mass Fraction ◽  
Internal Combustion Engines ◽  
Operating Conditions ◽  
High Mass ◽  
Parameter Determination ◽  
Complete Combustion ◽  
Burn Rate ◽  
The Impact ◽  
Wiebe Function

Abstract Current unmanned aerial vehicle (UAV) propulsion technologies includes hydrogen fuel cells, battery systems, and internal combustion engines (ICE). However, relying on a single propulsion technology might result in a limited operational range. This can be mitigated by utilizing a hybrid configuration involving a battery pack and an ICE or a fuel cell for charging. Due to its significant weight advantage and high mass-specific energy content, hydrogen (H2) is an ideal fuel for both power plant options. However, use of H2 with an ICE requires precise operational control through combustion process simulation with the predictive approximation of the mass fraction burned profile. In this area, the relatively simple single-Wiebe function is widely deployed for a variety of different fuels, as well as combustion regimes. In general, the description of the single-Wiebe function includes the extent of complete combustion (a), magnitude of the maximum burn rate (m), and combustion duration (θd). However, the literature often provides values for these parameters without necessarily relating them to operational characteristics that can influence ICE power. As a result, it is critical to correlate the burn rate of the fuel to ICE operating parameters, such as the engine compression ratio, inlet pressure, mean piston speed, exhaust gas recirculation level, equivalence ratio, and spark timing. Therefore, in an attempt to physically define these parameters, this effort performs a sensitivity analysis using linear regression (least squares method) to assess the impact of engine operating conditions on the Wiebe function in comparison to experimental data for port-fuel injected hydrogen ICEs. The result is a model that can estimate the values of a, m, and θd in combination with a relatively high coefficient of determination (R2) when compared to the experimental mass fraction burned profiles. Finally, others can expand this methodology to any experimental data for engine and fuel-specific Wiebe parameter determination.

Lean Burn Combustion of Iso-Octane in a Rapid Compression Machine Using Dual Mode Turbulent Jet Ignition System

2018 ◽  
Vol 11 (1) ◽  
pp. 95-107 ◽  
Author(s):  
Ravi Teja Vedula ◽  
Gerald Gentz ◽  
Thomas Stuecken ◽  
Elisa Toulson ◽  
Harold Schock
Keyword(s):  
Turbulent Jet ◽  
Rapid Compression Machine ◽  
Dual Mode ◽  
Lean Burn ◽  
Ignition System ◽  
Rapid Compression

Effect of Load Level on the Performance of a Dual Fuel Compression Ignition Engine Operating on Syngas Fuels With Varying H2/CO Content

2011 ◽  
Vol 133 (12) ◽  
Author(s):  
B. B. Sahoo ◽  
U. K. Saha ◽  
N. Sahoo
Keyword(s):  
Diesel Engine ◽  
Thermal Efficiency ◽  
Peak Pressure ◽  
Gaseous Fuel ◽  
Dual Fuel ◽  
Engine Fuel ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Engine Operation ◽  
Brake Thermal Efficiency

Syngas, an environmentally friendly alternative gaseous fuel for internal combustion engine operation, mainly consists of carbon monoxide (CO) and hydrogen (H2). It can substitute fossil diesel oil in a compression ignition diesel engine through dual fuel operation route. In the present investigation, experiments were conducted in a constant speed single cylinder direct injection diesel engine fuelled with syngas-diesel in a dual fuel operation mode. The main contribution of this study is to introduce the new synthetic gaseous fuel (syngas) including the possible use of CO gas, an alternative diesel engine fuel. In this work, four different H2 and CO compositions of syngas were chosen for dual fuel study under different engine loading levels. Keeping the same power output at the corresponding tested loads, the engine performance of dual fuel operations were compared to that of diesel mode for the entire load range. The maximum diesel replacement in the engine was found to be 72.3% for 100% H2 fuel. This amount replacement rate was reduced for the low energetic lower H2 content fuels. The brake thermal efficiency was always found highest (about 21%) in the case of diesel mode operation. However, the 100% H2 syngas showed a comparative performance level with diesel mode at the expense of higher NOx emissions. At 80% engine load, the brake thermal efficiency was found to be 15.7% for 100% CO syngas. This value increased to 16.1%, 18.3% and 19.8% when the 100% CO syngas composition was replaced by H2 contents of 50%, 75% and 100%, respectively. At part loads (i.e., at 20% and 40%), dual fuel mode resulted a poor performance including higher emission levels. In contrast, at higher loads, syngas fuels showed a good competitive performance to diesel mode. At all the tested loads, the NOx emission was observed highest for 100% H2 syngas as compared to other fuel conditions, and a maximum of 240 ppm was found at 100% load. However, when the CO fractions of 25%, 50% and 100%, were substituted to hydrogen fuel, the emission levels got reduced to 175 ppm, 127 ppm, and 114 ppm, respectively. Further, higher CO and HC emission levels were recorded for 25%, 50%, and 100% CO fraction syngas fuels due to their CO content. Ignition delay was found to increase for the dual fuel operation as compared to diesel mode, and also it seemed to be still longer for higher H2 content syngas fuels. The peak pressure and maximum rate of pressure rise were found to decrease for all the cases of dual fuel operation, except for 100% H2 syngas (beyond 60% load). The reduction in peak pressure resulted a rise in the exhaust gas temperature at all loads under dual fuel operation. The present investigation provides some useful experimental data which can be applied to the possible existing engine parameters modifications to produce a competitive syngas dual fuel performance at all the loading operations.

Experimental Comparison of Different Diesel-Biodiesel Blends in a CFR Engine

2012 ◽  
Author(s):  
G. Zamboni ◽  
S. Marelli ◽  
G. Marmorato ◽  
M. Capobianco
Keyword(s):  
Thermal Efficiency ◽  
Internal Combustion Engines ◽  
Methyl Esters ◽  
Cetane Number ◽  
Coconut Oil ◽  
Operating Conditions ◽  
Experimental Comparison ◽  
Brake Thermal Efficiency ◽  
Experimental Procedure ◽  
Four Levels

A wide experimental investigation was performed on a CFR engine with a view to comparing different renewable fuels in terms of Cetane Number, engine brake thermal efficiency and exhaust emissions. The CFR engine available at the Internal Combustion Engines Group of the University of Genoa was properly modified and fully instrumented in order to control operating conditions and to measure the average engine parameters and in-cylinder pressure diagrams. Aiming at the comparison of fuels obtained from various feedstock, an experimental procedure was then defined, including the standard Cetane Number evaluation and the definition of engine operating quantities in 16 different working points, considering four levels of rotational speed and load, for fixed levels of compression ratio and injection advance. Methyl-esters of rapeseed oil and of vegetable oils mix were investigated, while rapeseed, palm and coconut oil were also available. Several blends, obtained by mixing different biodiesel fractions with conventional diesel oil, assumed as reference fuel, were tested applying the defined experimental procedure. In the paper the experimental setup is firstly presented describing changes and instrumentation of CFR engine. The investigation program is then summarized in order to introduce results discussion, mainly focused on the analysis of the influence of the biodiesel content on brake thermal efficiency, NOx and soot emissions, taking into account fuel properties.

Performance and Emissions Characteristics Investigation of a Bi-Fuel SI Engine Fuelled by CNG and Gasoline

2006 ◽  
Author(s):  
Abazar Shamekhi ◽  
Nima Khatibzadeh ◽  
Amir H. Shamekhi
Keyword(s):  
Internal Combustion Engines ◽  
Combustion Engine ◽  
Engine Performance ◽  
Internal Combustion ◽  
Operating Conditions ◽  
Spark Ignition Engine ◽  
Engine Fuel ◽  
Wide Range ◽  
Performance And Emissions ◽  
Pollutant Sources

Nowadays, increased attention has been focused on internal combustion engine fuels. Regarding environmental effects of internal combustion engines particularly as pollutant sources and depletion of fossil fuel resources, compressed natural gas (CNG) has been introduced as an effective alternative to gasoline and diesel fuel in many applications. A high research octane number allows combustion at higher compression ratios without knocking and good emission characteristics of HC and CO are major benefits of CNG as an engine fuel. In this paper, CNG as an alternative fuel in a spark ignition engine has been considered. Engine performance and exhaust emissions have been experimentally studied for CNG and gasoline in a wide range of the engine operating conditions.

Sign in / Sign up

Export Citation Format

Share Document