scholarly journals Numerical Analysis of Fuel Effects on Advanced Compression Ignition Using a Virtual Cooperative Fuel Research Engine Model

2020 ◽  
Author(s):  
Krishna C. Kalvakala ◽  
Pinaki Pal ◽  
Yunchao Wu ◽  
Goutham Kukkadapu ◽  
Christopher Kolodziej ◽  
...  
Keyword(s):  
Engine Speed ◽  
Driving Forces ◽  
Engine Performance ◽  
Kinetic Mechanism ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Charge Condition ◽  
Engine Model ◽  
Primary Reference ◽  
Fuel Effects

Abstract Growing environmental concerns and demand for better fuel economy are driving forces that motivate the research for more advanced engines. Multi-mode combustion strategies have gained attention for their potential to provide high thermal efficiency and low emissions for light-duty applications. These strategies target optimizing the engine performance by correlating different combustion modes to load operating conditions. The extension from boosted SI mode at high loads to advanced compression ignition (ACI) mode at low loads can be achieved by increasing compression ratio and utilizing intake air heating. Further, in order to enable an accurate control of intake charge condition for ACI mode and rapid mode-switches, it is essential to gain fundamental insights into the autoignition process. Within the scope of ACI, homogeneous charge compression ignition (HCCI) mode is of significant interest. It is known for its potential benefits, operation at low fuel consumption, low NOx and PM emissions. In the present work, a virtual Cooperative Fuel Research (CFR) engine model is used to analyze fuel effects on ACI combustion. In particular, the effect of fuel Octane Sensitivity (S) (at constant RON) on autoignition propensity is assessed under beyond-RON (BRON) and beyond-MON (BMON) ACI conditions. The 3D CFR engine computational fluid dynamics (CFD) model employs finite-rate chemistry approach with multi-zone binning strategy to capture autoignition. Two binary blends with Research Octane Number (RON) of 90 are chosen for this study: Primary reference fuel (PRF) with S = 0, and toluene-heptane (TH) blend with S = 10.8, representing paraffinic and aromatic gasoline surrogates. Reduced mechanisms for these blends are generated from a detailed gasoline surrogate kinetic mechanism. Simulation results with the reduced mechanisms are validated against experimental data from an in-house CFR engine, with respect to in-cylinder pressure, heat release rate and combustion phasing. Thereafter, the sensitivity of combustion behavior to ACI operating condition (BRON vs BMON), air-fuel ratio (λ = 2 and 3), and engine speed (600 and 900rpm) is analyzed for both fuels. It is shown that the sensitivity of a fuel’s autoignition characteristics to λ and engine speed significantly differs at BRON and BMON conditions. Moreover, this sensitivity is found to vary among fuels, despite the same RON. This study also indicates that the octane index (OI) fails to capture the trend in the variation of autoignition propensity with S under BMON conditions.

NUMERICAL ANALYSIS OF FUEL EFFECTS ON ADVANCED COMPRESSION IGNITION USING A COOPERATIVE FUEL RESEARCH ENGINE COMPUTATIONAL FLUID DYNAMICS MODEL

2021 ◽  
pp. 1-34
Author(s):  
Krishna C Kalvakala ◽  
Pinaki Pal ◽  
Yunchao Wu ◽  
Goutham Kukkadapu ◽  
Christopher Kolodziej ◽  
...  
Keyword(s):  
Fluid Dynamics ◽  
Computational Fluid Dynamics ◽  
Heat Release ◽  
Engine Speed ◽  
Driving Forces ◽  
Engine Performance ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Charge Condition ◽  
Fuel Effects

Abstract Growing environmental concerns and demand for better fuel economy are driving forces that motivate the research for more advanced engines. Multi-mode combustion strategies have gained attention for their potential to provide high thermal efficiency and low emissions for light-duty applications. These strategies target optimizing the engine performance by correlating different combustion modes to load operating conditions. The extension from boosted SI mode at high loads to advanced compression ignition (ACI) mode at low loads can be achieved by increasing compression ratio and utilizing intake air heating. Further, in order to enable an accurate control of intake charge condition for ACI mode and rapid mode-switches, it is essential to gain fundamental insights into the autoignition process. Within the scope of ACI, homogeneous charge compression ignition (HCCI) mode is of significant interest. It is known for its potential benefits, operation at low fuel consumption, low NOx and PM emissions. In the present work, a virtual Cooperative Fuel Research (CFR) engine model is used to analyze fuel effects on ACI combustion. In particular, the effect of fuel Octane Sensitivity (S) (at constant RON) on autoignition propensity is assessed under beyond-RON (BRON) and beyond-MON (BMON) ACI conditions. The 3D CFR engine computational fluid dynamics (CFD) model employs finite-rate chemistry approach with multi-zone binning strategy to capture autoignition. Two binary blends with Research Octane Number (RON) of 90 are chosen for this study: Primary reference fuel (PRF) with S = 0, and toluene-heptane (TH) blend with S = 10.8, representing paraffinic and aromatic gasoline surrogates. Reduced mechanisms for these blends are generated from a detailed gasoline surrogate kinetic mechanism. Simulation results with the reduced mechanisms are validated against experimental data from an in-house CFR engine, with respect to in-cylinder pressure, heat release rate and combustion phasing. Thereafter, the sensitivity of combustion behavior to ACI operating condition (BRON vs BMON), air-fuel ratio (λ = 2 and 3), and engine speed (600 and 900rpm) is analyzed for both fuels. It is shown that the sensitivity of a fuel's autoignition characteristics to λ and engine speed significantly differs at BRON and BMON conditions. Moreover, this sensitivity is found to vary among fuels, despite the same RON. It is also observed that the presence of low temperature heat release (LTHR) under BRON condition leads to more sequential autoignition and longer combustion duration than BMON condition. Finally, the study indicates that the octane index (OI) fails to capture the trend in the variation of autoignition propensity with S under BMON condition.

Vibration Spectra as a Feedback for Controlling Multicylinder Engine Performance

1992 ◽  
Vol 3 (2) ◽  
pp. 176-192
Author(s):  
T.W. Abou-Arab ◽  
M. Othman ◽  
Y.S.H. Najjar
Keyword(s):  
Engine Speed ◽  
Engine Performance ◽  
Feedback System ◽  
Operating Conditions ◽  
Flow Induced Vibration ◽  
Vibration Spectra ◽  
Parametric Studies ◽  
Vibration Pattern ◽  
Engine Components ◽  
Heat And Fluid Flow

Increasing requirements for vehicle confort, economy and reliability lead some investigators to consider the relationships between the mechanical vibrations with the heat and fluid flow induced vibration and noise in a more accurate manner. This paper describes the variation of the vibration phenomena associated with the motion of some engine components under different operating conditions. The measured vibration spectra indicates its capability in predicting symptoms of early engine failures, hence, expediting their control using a suitable feedback system. Parametric studies involving the effect of air-fuel ratio, ignition timing and engine speed on the vibration pattern are also carried out. These studies indicate that the amplitude of vibration decreases as the speed increases then increases again after certain engine speed. The effect of ignition system characteristic on the induced vibration are obtained and the correlation between the developed power and the engine dynamics over a range of operating conditions are discussed.

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.

scholarly journals Engine Performance of a Gardener Compression Ignition Engine using Rapeseed Methyl Esther

2019 ◽  
Vol 4 (2) ◽  
Author(s):  
Hamisu A Dandajeh ◽  
Talib O Ahmadu
Keyword(s):  
Mass Flow Rate ◽  
Mass Flow ◽  
Flow Rate ◽  
Equivalence Ratio ◽  
Engine Speed ◽  
Engine Performance ◽  
Combustion Characteristics ◽  
Compression Ignition ◽  
Compression Ignition Engine ◽  
Air Mass

This paper presents an experimental investigation on the influence of engine speed on the combustion characteristics of a Gardener compression ignition engine fueled with rapeseed methyl esther (RME). The engine has a maximum power of 14.4 kW and maximum speed of 1500 rpm. The experiment was carried out at speeds of 750 and 1250 rpm under loads of 4, 8, 12, 16 and 18 kg. Variations of cylinder pressure with crank angle degrees and cylinder volume have been examined. It was found that RME demonstrated short ignition delay primarily due to its high cetane number and leaner fuel properties (equivalence ratio (φ) = 0.22 at 4kg). An increase in thermal efficiency but decrease in volumetric efficiency was recorded due to increased brake loads. Variations in fuel mass flow rate, air mass flow rate, exhaust gas temperatures and equivalence ratio with respect to brake mean effective pressure at engine speeds of 750 and 1250 rpm were also demonstrated in this paper. Higher engine speed of 1250 rpm resulted in higher fuel and air mass flow rates, exhaust temperature, brake power and equivalent ratio but lower volumetric efficiency. Keywords— combustion characteristics, engine performance, engine speed, rapeseed methyl Esther

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.

A Comprehensive Study on Natural Gas HCCI Engine Response to Different Initial Conditions via a Thermo-Kinetic Engine Model

2009 ◽  
Author(s):  
Omid Jahanian ◽  
Seyed Ali Jazayeri
Keyword(s):  
Natural Gas ◽  
Initial Conditions ◽  
Chemical Species ◽  
Engine Performance ◽  
Operating Conditions ◽  
Zone Model ◽  
Operating Characteristics ◽  
Hcci Engine ◽  
Engine Model ◽  
Homogenous Charge Compression Ignition

Homogenous Charge Compression Ignition (HCCI) combustion is a promising concept to reduce engine emissions and fuel consumption. In this paper, a thermo-kinetic model is developed to study the operating characteristics of a natural gas HCCI engine. The zero-dimensional single zone model consist detail chemical kinetics of natural gas oxidation including 325 reactions with 53 chemical species, and is validated with experimental results of reference works for two different engines, Volvo TD 100 and Caterpillar 3500, in 5 operating conditions. Then, the influence of parameters such as manifold temperature/pressure and equivalence ratio on in-cylinder temperature/pressure trends and start of combustion is studied. Measurements for Volvo engine show that SOC occurs 3–5 CAD earlier with every 15K increase in initial temperature. These whole results are explained in detail to describe the engine performance thoroughly.

scholarly journals Numerical Analysis of Fuel Effects on Advanced Compression Ignition Using a Virtual Cooperative Fuel Research Engine Model

2021 ◽  
Author(s):  
Krishna Kalvakala ◽  
Pinaki Pal ◽  
Yunchao Wu ◽  
Goutham Kukkadapu ◽  
Christopher Kolodziej ◽  
...  
Keyword(s):  
Numerical Analysis ◽  
Compression Ignition ◽  
Engine Model ◽  
Fuel Effects

SIMULATION ANALYSIS OF SPARK IGNITION ENGINE INTAKE MANIFOLD FOR BETTER PERFORMANCE

2017 ◽  
Vol 79 (7-4) ◽  
Author(s):  
Muhammad Hariz Khairuddin ◽  
Muhammad Fitri Shamsul Bahri ◽  
Afiq Aiman Dahlan ◽  
Mahadhir Mohammad ◽  
Mohd Farid Muhamad Said
Keyword(s):  
Engine Speed ◽  
Simulation Analysis ◽  
Engine Performance ◽  
Simulation Software ◽  
Spark Ignition Engine ◽  
Intake Manifold ◽  
Engine Simulation ◽  
Engine Model ◽  
Air Intake ◽  
Manifold System

Intake manifold system is one of the important component in the engine system which functions to evenly distribute the air flows into every cylinder of the engine. With the restricted air intake rule regulation, the intake air system for a car must be properly design in order to minimize the performance dropped caused by the restrictor. The paper presents the study on the effects of intake design parameter towards the performance of the engine and then improves the performance of previous intake manifold system. This study starts with the development of Honda CBR 600RR engine model and intake manifold system model using GT-Power engine simulation software to be used for the simulation purposes. After developing the reference engine model, the parametric study was carried out to study the effect of the intake manifold parameter design on the engine performance. The optimization process was then performed to achieve the target of improvement which has already been set prior to performing the optimization. The final results show an increase up to 4.83% and 4.45% of torque and air flow rate respectively at the desired operating range of engine speed.

Estimating the Drag Developed by a High Bypass Ratio Turbofan Engine

2018 ◽  
Author(s):  
M. S. Zawislak ◽  
D. J. Cerantola ◽  
A. M. Birk
Keyword(s):  
Engine Performance ◽  
Operating Conditions ◽  
Zone Model ◽  
Pressure System ◽  
Cross Sectional ◽  
Turbofan Engine ◽  
Engine Model ◽  
Integration Techniques ◽  
Drag Analysis ◽  
Bypass Ratio

A high bypass ratio turbofan engine capable of powering the Boeing 757 was considered for thrust and drag analysis. A quasi-2D engine model applying the fundamental thermodynamics conservation equations and practical constraints determined engine performance and provided cross-sectional areas in the low-pressure system. Coupled with suggestions on boat-tail angle and curvature from literature, a representative bypass duct and primary exhaust nozzle was created. 3D steady-RANS simulations using Fluent® 18 were performed on a 1/8th axisymmetric section of the geometry. A modified 3D fan zone model forcing radial equilibrium was used to model the fan and bypass stator. Takeoff speed and cruise operating conditions were modeled and simulated to identify changes in thrust composition and intake sensitivity. Comparison between net thrust predictions by the engine model and measured in CFD were within grid uncertainty and model sensitivity at cruise. Trends observed in a published database were satisfied and calculations coincided with GasTurb™ 8.0. Verification of thrust in this manner gave confidence to the aerodynamic performance prediction of this modest CFD. Obtaining a baseline bypass design would allow rapid testing of aftermarket components and integration techniques in a realistic flow-field without reliance on proprietary engine data.

scholarly journals Investigation on effect of equivalence ratio and engine speed on homogeneous charge compression ignition combustion using chemistry based CFD code

2014 ◽  
Vol 18 (1) ◽  
pp. 89-96 ◽  
Author(s):  
Jafar Ghafouri ◽  
Sina Shafee ◽  
Amin Maghbouli
Keyword(s):  
Natural Gas ◽  
Equivalence Ratio ◽  
Engine Speed ◽  
Homogeneous Charge Compression Ignition ◽  
Initial Pressure ◽  
Methane Combustion ◽  
Operating Conditions ◽  
Compression Ignition ◽  
Detailed Chemical Kinetics ◽  
Homogeneous Charge

Combustion in a large-bore natural gas fuelled diesel engine operating under Homogeneous Charge Compression Ignition mode at various operating conditions is investigated in the present paper. Computational Fluid Dynamics model with integrated chemistry solver is utilized and methane is used as surrogate of natural gas fuel. Detailed chemical kinetics mechanism is used for simulation of methane combustion. The model results are validated using experimental data by Aceves, et al. (2000), conducted on the single cylinder Volvo TD100 engine operating at Homogeneous Charge Compression Ignition conditions. After verification of model predictions using in-cylinder pressure histories, the effect of varying equivalence ratio and engine speed on combustion parameters of the engine is studied. Results indicate that increasing engine speed provides shorter time for combustion at the same equivalence ratio such that at higher engine speeds, with constant equivalence ratio, combustion misfires. At lower engine speed, ignition delay is shortened and combustion advances. It was observed that increasing the equivalence ratio retards the combustion due to compressive heating effect in one of the test cases at lower initial pressure. Peak pressure magnitude is increased at higher equivalence ratios due to higher energy input.

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