Effect of Fuel Injection Pressure and Engine Speed on Performance, Emissions, Combustion, and Particulate Investigations of Gasohols Fuelled Gasoline Direct Injection Engine

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Nikhil Sharma ◽  
Avinash Kumar Agarwal
Keyword(s):  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Driving Forces ◽  
Direct Injection ◽  
Engine Performance ◽  
Injection Pressure ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Primary Alcohols ◽  
Renewable Fuel

Abstract Fuel availability, global warming, and energy security are the three main driving forces, which determine suitability and long-term implementation potential of a renewable fuel for internal combustion engines for a variety of applications. Comprehensive engine experiments were conducted in a single-cylinder gasoline direct injection (GDI) engine prototype having a compression ratio of 10.5, for gaining insights into application of mixtures of gasoline and primary alcohols. Performance, emissions, combustion, and particulate characteristics were determined at different engine speeds (1500, 2000, 2500, 3000 rpm), different fuel injection pressures (FIP: 40, 80, 120, 160 bars) and different test fuel blends namely 15% (v/v) butanol, ethanol, and methanol blended with gasoline, respectively (Bu15, E15, and M15) and baseline gasoline at a fixed (optimum) spark timing of 24 deg before top dead center (bTDC). For a majority of operating conditions, gasohols exhibited superior characteristics except minor engine performance penalty. Gasohols therefore emerged as serious candidate as a transitional renewable fuel for utilization in the existing GDI engines, without requirement of any major hardware changes.

scholarly journals Predicting Cycle-to-Cycle Variation With Concurrent Cycles in a Gasoline Direct Injected Engine With Large Eddy Simulations

2018 ◽  
Author(s):  
Daniel Probst ◽  
Sameera Wijeyakulasuriya ◽  
Eric Pomraning ◽  
Janardhan Kodavasal ◽  
Riccardo Scarcelli ◽  
...  
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Engine Performance ◽  
Turnaround Time ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Cycle Variation ◽  
Spark Timing ◽  
Large Eddy ◽  
Operating Points

High cycle-to-cycle variation (CCV) is detrimental to engine performance, as it leads to poor combustion and high noise and vibration. In this work, CCV in a gasoline engine is studied using large eddy simulation (LES). The engine chosen as the basis of this work is a single-cylinder gasoline direct injection (GDI) research engine. Two stoichiometric part-load engine operating points (6 BMEP, 2000 RPM) were evaluated: a non-dilute (0% EGR) case and a dilute (18% EGR) case. The experimental data for both operating conditions had 500 cycles. The measured CCV in IMEP was 1.40% for the non-dilute case and 7.78% for the dilute case. To estimate CCV from simulation, perturbed concurrent cycles of engine simulations were compared to consecutively obtained engine cycles. The motivation behind this is that running consecutive cycles to estimate CCV is quite time-consuming. For example, running 100 consecutive cycles requires 2–3 months (on a typical cluster), however, by running concurrently one can potentially run all 100 cycles at the same time and reduce the overall turnaround time for 100 cycles to the time taken for a single cycle (2 days). The goal of this paper is to statistically determine if concurrent cycles, with a perturbation applied to each individual cycle at the start, can be representative of consecutively obtained cycles and accurately estimate CCV. 100 cycles were run for each case to obtain statistically valid results. The concurrent cycles began at different timings before the combustion event, with the motivation to identify the closest time before spark to minimize the run time. Only a single combustion cycle was run for each concurrent case. The calculated standard deviation of peak pressure and coefficient of variance (COV) of indicated mean effective pressure (IMEP) were compared between the consecutive and concurrent methods to quantify CCV. It was found that the concurrent method could be used to predict CCV with either a velocity or numerical perturbation. A large and small velocity perturbation were compared and both produced correct predictions, implying that the type of perturbation is not important to yield a valid realization. Starting the simulation too close to the combustion event, at intake valve close (IVC) or at spark timing, under-predicted the CCV. When concurrent simulations were initiated during or before the intake even, at start of injection (SOI) or earlier, distinct and valid realizations were obtained to accurately predict CCV for both operating points. By simulating CCV with concurrent cycles, the required wall clock time can be reduced from 2–3 months to 1–2 days. Additionally, the required core-hours can be reduced up to 41%, since only a portion of each cycle needs to be simulated.

Experimental and Numerical Analysis on the Influence of Direct Fuel Injection Into O2-Depleted Environment of a GDI-HCCI Engine

2020 ◽  
Author(s):  
Ratnak Sok ◽  
Jin Kusaka
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Single Pulse ◽  
Gasoline Direct Injection ◽  
Injection Timing ◽  
Rich Mixture ◽  
Intake Stroke ◽  
Shift Reaction ◽  
Direct Fuel Injection

Abstract Injected gasoline into the O2-depleted environment in the recompression stroke can be converted into light hydrocarbons due to thermal cracking, partial oxidation, and water-gas shift reaction. These reformate species influence the combustion phenomena of gasoline direct injection homogeneous charge compression ignition (GDI-HCCI) engines. In this work, a production-based single-cylinder research engine was boosted to reach IMEPn = 0.55 MPa in which its indicated efficiency peaks at 40–41%. Experimentally, the main combustion phases are advanced under single-pulse direct fuel injection into the negative valve overlap (NVO) compared with that of the intake stroke. NVO peak in-cylinder pressures are lower than that of motoring, which emphasizes that endothermic reaction occurs during the interval. Low O2 concentration could play a role in this evaporative charge cooling effect. This phenomenon limits the oxidation reaction, and the thermal effect is not pronounced. For understanding the recompression reaction phenomena, 0D simulation with three different chemical reaction mechanisms is studied to clarify that influences of direct injection timing in NVO on combustion advancements are kinetically limited by reforming. The 0D results show the same increasing tendencies of classical reformed species of rich-mixture such as C3H6, C2H4, CH4, CO, and H2 as functions of injection timings. By combining these reformed species into the main fuel-air mixture, predicted ignition delays are shortened. The effects of the reformed species on the main combustion are confirmed by 3D-CFD calculation, and the results show that OH radical generation is advanced under NVO fuel injection compared with that of intake stroke conditions thus earlier heat release and cylinder pressure are noticeable. Also, parametric studies on injection pressure and double-pulse injections on engine combustion are performed experimentally.

Distribution of Two-Stage Direct Injection CNG-Air Mixture near Lean Limit Using CFD

2013 ◽  
Vol 465-466 ◽  
pp. 448-452
Author(s):  
Mas Fawzi ◽  
Bukhari Manshoor ◽  
Yoshiyuki Kidoguchi ◽  
Yuzuru Nada
Keyword(s):  
Fuel Injection ◽  
Direct Injection ◽  
Engine Performance ◽  
Injection Pressure ◽  
Gas Jet ◽  
Exhaust Emission ◽  
Injection Technique ◽  
Injection Timing ◽  
Two Stage ◽  
Lean Burn

Previous work shows that gas-jet ignition with two-stage injection technique is effective to extend lean combustible ranges of CNG engines. In this report, the robustness of the gas-jet ignition with two-stage injection method was investigated purposely to improve the performance of a lean burn direct injection CNG engine. The experiment was conducted using an engine at speed of 900 rpm, fuel-injection-pressure of 3MPa, equivalence ratio at 0.8, and ignition timing at top dead center. The effect of first injection timing on the test engine performance and exhaust emission was analyzed. First injection timings near the gas-jet ignition produced unstable combustion with occurrence of misfires except at a timing which produced distinctively good combustion with low HC and CO emissions. Computational fluid dynamics was used to provide hindsight of the fuel-air mixture distribution that might be the cause of misfires occurrence at certain injection timings.

scholarly journals Particulate emissions from a highly boosted gasoline direct injection engine

2017 ◽  
Vol 19 (3) ◽  
pp. 347-359 ◽  
Author(s):  
Felix Leach ◽  
Richard Stone ◽  
Dave Richardson ◽  
Andrew Lewis ◽  
Sam Akehurst ◽  
...  
Keyword(s):  
Particle Number ◽  
Fuel Injection ◽  
Direct Injection ◽  
Injection Pressure ◽  
Back Pressure ◽  
Gasoline Direct Injection ◽  
Exhaust Gas ◽  
Fuel Injection Pressure ◽  
Gas Recirculation ◽  
Operating Points

Downsized, highly boosted, gasoline direct injection engines are becoming the preferred gasoline engine technology to ensure that increasingly stringent fuel economy and emissions legislation are met. The Ultraboost project engine is a 2.0-L in-line four-cylinder prototype engine, designed to have the same performance as a 5.0-L V8 naturally aspirated engine but with reduced fuel consumption. It is important to examine particle number emissions from such extremely highly boosted engines to ensure that they are capable of meeting current and future emissions legislation. The effect of such high boosting on particle number emissions is reported in this article for a variety of operating points and engine operating parameters. The effect of engine load, air–fuel ratio, fuel injection pressure, fuel injection timing, ignition timing, inlet air temperature, exhaust gas recirculation level, and exhaust back pressure has been investigated. It is shown that particle number emissions increase with increase in cooled, external exhaust gas recirculation and engine load, and decrease with increase in fuel injection pressure and inlet air temperature. Particle number emissions are shown to fall with increased exhaust back pressure, a key parameter for highly boosted engines. The effects of these parameters on the particle size distributions from the engine have also been evaluated. Significant changes to the particle size spectrum emitted from the engine are seen depending on the engine operating point. Operating points with a bias towards very small particle sizes were noted.

scholarly journals Predicting Cycle-to-Cycle Variation With Concurrent Cycles in a Gasoline Direct Injected Engine With Large Eddy Simulations

2019 ◽  
Vol 142 (4) ◽  
Author(s):  
Daniel M. Probst ◽  
Sameera Wijeyakulasuriya ◽  
Eric Pomraning ◽  
Janardhan Kodavasal ◽  
Riccardo Scarcelli ◽  
...  
Keyword(s):  
Gasoline Engine ◽  
Direct Injection ◽  
Engine Performance ◽  
Operating Conditions ◽  
Gasoline Direct Injection ◽  
Effective Pressure ◽  
Cycle Variation ◽  
Brake Mean Effective Pressure ◽  
Large Eddy ◽  
Operating Points

Abstract High cycle-to-cycle variation (CCV) is detrimental to engine performance, as it leads to poor combustion and high noise and vibration. In this work, CCV in a gasoline engine is studied using large eddy simulation (LES). The engine chosen as the basis of this work is a single-cylinder gasoline direct injection (GDI) research engine. Two stoichiometric part-load engine operating points (6 brake mean effective pressure (BMEP) and 2000 revolutions per minute) were evaluated: a nondilute (0% exhaust gas recirculation (EGR)) case and a dilute (18% EGR) case. The experimental data for both operating conditions had 500 cycles. The measured CCV in indicated mean effective pressure (IMEP) was 1.40% for the nondilute case and 7.78% for the dilute case. To estimate CCV from simulation, perturbed concurrent cycles of engine simulations were compared with consecutively obtained engine cycles. The motivation behind this is that running consecutive cycles to estimate CCV is quite time consuming. For example, running 100 consecutive cycles requires 2–3 months (on a typical cluster); however, by running concurrently, one can potentially run all 100 cycles at the same time and reduce the overall turnaround time for 100 cycles to the time taken for a single cycle (2 days). The goal of this paper is to statistically determine if concurrent cycles, with a perturbation applied to each individual cycle at the start, can be representative of consecutively obtained cycles and accurately estimate CCV. 100 cycles were run for each case to obtain statistically valid results. The concurrent cycles began at different timings before the combustion event, with the motivation to identify the closest time before spark to minimize the run time. Only a single combustion cycle was run for each concurrent case. The calculated standard deviation of peak pressure and coefficient of variance (COV) of IMEP were compared between the consecutive and concurrent methods to quantify CCV. It was found that the concurrent method could be used to predict CCV with either a velocity or numerical perturbation. Both a large and small velocity perturbations were compared, and both produced correct predictions, implying that the type of perturbation is not important to yield a valid realization. Starting the simulation too close to the combustion event, at intake valve close (IVC) or at spark timing, underpredicted the CCV. When concurrent simulations were initiated during or before the intake even, at start of injection (SOI) or earlier, distinct and valid realizations were obtained to accurately predict CCV for both operating points. By simulating CCV with concurrent cycles, the required wall clock time can be reduced from 2–3 months to 1–2 days. In addition, the required core-hours can be reduced up to 41%, since only a portion of each cycle needs to be simulated.

Simulation of Turbulent Combustion in Gasoline Direct Injection Spark-Ignited Engines Using a Stochastic Reactor Model

2021 ◽  
Author(s):  
Brady M. Wilmer ◽  
William F. Northrop
Keyword(s):  
Experimental Data ◽  
Flame Front ◽  
Internal Combustion Engines ◽  
Fuel Injection ◽  
Direct Injection ◽  
Turbulent Flame ◽  
Gasoline Direct Injection ◽  
Combustion Model ◽  
Reactor Model ◽  
Turbulent Flame Speed

Abstract In this work, a stochastic reactor model (SRM) is presented that bridges the gap between multi-dimensional computational fluid dynamics (CFD) models and zero-dimensional models for simulating spark-ignited internal combustion engines. The quasi-dimensional approach calculates spatial temperature and composition of stochastic “particles” in the combustion chamber without defining their spatial position, thus allowing for mixture stratification while keeping computational costs low. The SRM simulates flame propagation using a three-zone combustion model consisting of burned gas, flame front, and unburned gas. This “flame brush” approach assumes a hemispherical flame front that propagates through the cylinder based on estimated turbulent flame speed. Cycle-averaged turbulence intensity (u’) is used in the model, calibrated using experimental data. Through the use of a kinetic mechanism, the model predicts key emissions such as CO, CO2, NO, NO2, and HC from both port fuel injection (PFI) and gasoline direct injection (GDI) engines, the latter through the implementation of a simplified spray model. Experimental data from three engines, two GDI and one PFI, were used to validate the model and calibrate cycle-averaged u’. Across all engines, the model was able to produce pressure curves that matched the experimental data. In terms of emissions, the simplified chemical kinetics mechanism matched trends of the experimental data, with the PFI results having higher accuracy. Pressure, burned fraction, and engine-out emissions predictions show that the SRM can reliably match experimental results in certain operating ranges, thus providing a viable alternative to complex CFD and single zone models.

A Comprehensive Model for Pilot-Ignited, Coal-Water Mixture Combustion in a Direct-Injection Diesel Engine

1990 ◽  
Vol 112 (3) ◽  
pp. 384-390
Author(s):  
S. Wahiduzzaman ◽  
P. N. Blumberg ◽  
R. Keribar ◽  
C. I. Rackmil
Keyword(s):  
Diesel Engine ◽  
Fuel Injection ◽  
Direct Injection ◽  
Accurate Determination ◽  
Engine Performance ◽  
Operating Conditions ◽  
Combustion Model ◽  
Water Mixture ◽  
Engine Design ◽  
Pilot Fuel

A combustion model has been developed for a direct-injected diesel engine fueled with coal-water slurry mixture (CWM) and assisted by diesel pilot injection. The model combines the unique heat and mass transport and chemical kinetic processes of CWM combustion with the normal in-cylinder processes of a diesel engine. It includes a two-stage evaporation submodel for the drying of the CWM droplet, a global kinetic submodel for devolatilization, and a char combustion submodel describing surface gasification by oxygen, carbon dioxide, and water vapor. The combustion volume is discretized into multiple zones, each of whose individual thermochemistry is determined by in-situ equilibrium calculations. This provides an accurate determination of the boundary conditions for the CWM droplet combustion submodels and the gas phase heat release. A CWM fuel jet development, entrainment, and mixing submodel is used to calculate the mass of unburned air in each of the burned zones. A separate submodel of diesel pilot fuel combustion is incorporated into the overall model, as it has been found that pilot fuel is required to achieve satisfactory combustion under many operating conditions. The combustion model is integrated with an advanced engine design analysis code. The integrated model can be used as a tool for exploration of the effects of fuel characteristics, fuel injection parameters, and engine design variables on engine performance, and in the assessment of the effects of component design modifications on the overall efficiency of the engine and the degree of coal burnout achieved.

Sign in / Sign up

Export Citation Format

Share Document