Extending Lean and EGR-Dilute Operating Limits of a Modern GDI Engine Using a Low-Energy Transient Plasma Ignition System

The efficiency improvement and emissions reduction potential of lean and EGR dilute operation of spark-ignition gasoline engines is well understood and documented. However, dilute operation is generally limited by deteriorating combustion stability with increasing inert gas levels. The combustion stability decreases due to reduced mixture flame speeds resulting in significantly increased combustion initiation periods and burn durations. A study was designed and executed to evaluate the potential to extend lean and EGR-dilute limits using a low-energy transient plasma ignition system. The low-energy transient plasma was generated by nano-second pulses and its performance compared to a conventional transistorized coil ignition system operated on an automotive, gasoline direct injection (GDI) single-cylinder research engine. The experimental assessment was focused on steady-state experiments at the part load condition of 1500 rpm 5.6 bar IMEP, where dilution tolerance is particularly critical to improving efficiency and emissions performance. Experimental results suggest that the energy delivery process of the low-energy transient plasma ignition system significantly improves part load dilution tolerance by reducing the early flame development period. Statistical analysis of relevant combustion metrics was performed in order to further investigate the effects of the advanced ignition system on combustion stability. Results confirm that at select operating conditions EGR tolerance and lean limit could be improved by as much as 20% (from 22.7 to 27.1% EGR) and nearly 10% (from λ=1.55 to 1.7) with the low-energy transient plasma ignition system.

Download Full-text

Extending Lean and Exhaust Gas Recirculation-Dilute Operating Limits of a Modern Gasoline Direct-Injection Engine Using a Low-Energy Transient Plasma Ignition System

Journal of Engineering for Gas Turbines and Power ◽

10.1115/1.4033470 ◽

2016 ◽

Vol 138 (11) ◽

Cited By ~ 20

Author(s):

James Sevik ◽

Thomas Wallner ◽

Michael Pamminger ◽

Riccardo Scarcelli ◽

Dan Singleton ◽

...

Keyword(s):

Direct Injection ◽

Exhaust Gas Recirculation ◽

Low Energy ◽

Gasoline Direct Injection ◽

Combustion Stability ◽

Exhaust Gas ◽

Ignition System ◽

Plasma Ignition ◽

Gas Recirculation ◽

Transient Plasma

The efficiency improvement and emissions reduction potential of lean and exhaust gas recirculation (EGR)-dilute operation of spark-ignition gasoline engines is well understood and documented. However, dilute operation is generally limited by deteriorating combustion stability with increasing inert gas levels. The combustion stability decreases due to reduced mixture flame speeds resulting in significantly increased combustion initiation periods and burn durations. A study was designed and executed to evaluate the potential to extend lean and EGR-dilute limits using a low-energy transient plasma ignition system. The low-energy transient plasma was generated by nanosecond pulses and its performance compared to a conventional transistorized coil ignition (TCI) system operated on an automotive, gasoline direct-injection (GDI) single-cylinder research engine. The experimental assessment was focused on steady-state experiments at the part load condition of 1500 rpm 5.6 bar indicated mean effective pressure (IMEP), where dilution tolerance is particularly critical to improving efficiency and emission performance. Experimental results suggest that the energy delivery process of the low-energy transient plasma ignition system significantly improves part load dilution tolerance by reducing the early flame development period. Statistical analysis of relevant combustion metrics was performed in order to further investigate the effects of the advanced ignition system on combustion stability. Results confirm that at select operating conditions EGR tolerance and lean limit could be improved by as much as 20% (from 22.7 to 27.1% EGR) and nearly 10% (from λ = 1.55 to 1.7) with the low-energy transient plasma ignition system.

Download Full-text

Multiple Injection Strategies for Improved Combustion Stability under Stratified Part Load Conditions in a Spray Guided Gasoline Direct Injection (SGDI) Engine

10.4271/2011-01-1228 ◽

2011 ◽

Cited By ~ 16

Author(s):

Lars Schmidt ◽

Justin Seabrook ◽

John Stokes ◽

Mohd Faizan Ahmad Zuhdi ◽

Steven Begg ◽

...

Keyword(s):

Direct Injection ◽

Gasoline Direct Injection ◽

Combustion Stability ◽

Multiple Injection ◽

Part Load ◽

Load Conditions ◽

Injection Strategies

Download Full-text

Comparison between gasoline direct injection and compressed natural gas port fuel injection under maximum load condition

Energy ◽

10.1016/j.energy.2020.117173 ◽

2020 ◽

Vol 197 ◽

pp. 117173 ◽

Cited By ~ 1

Author(s):

Jeongwoo Lee ◽

Cheolwoong Park ◽

Jongwon Bae ◽

Yongrae Kim ◽

Sunyoup Lee ◽

...

Keyword(s):

Natural Gas ◽

Fuel Injection ◽

Direct Injection ◽

Load Condition ◽

Maximum Load ◽

Gasoline Direct Injection ◽

Compressed Natural Gas ◽

Port Fuel Injection

Download Full-text

Numerical and Experimental Analysis of Ignition and Combustion Stability in EGR Dilute GDI Operation

Volume 1: Large Bore Engines; Fuels; Advanced Combustion; Emissions Control Systems ◽

10.1115/icef2014-5607 ◽

2014 ◽

Cited By ~ 7

Author(s):

Riccardo Scarcelli ◽

Nicholas S. Matthias ◽

Thomas Wallner

Keyword(s):

Flame Propagation ◽

Numerical Results ◽

Operating Conditions ◽

Combustion Stability ◽

Ignition Process ◽

Ignition System ◽

Cyclic Variability ◽

Beneficial Effects ◽

Engine Testing ◽

Ignition And Combustion

This paper discusses the characteristics of EGR dilute GDI engines in terms of combustion stability. A combined approach consisting of RANS numerical simulations integrated with experimental engine testing is used to analyze the effect of the ignition source on flame propagation under dilute operating conditions. A programmable spark-based ignition system is compared to a production spark system in terms of cyclic variability and ultimately indicated efficiency. 3D-CFD simulations are carried out for multiple cycles with the goal of establishing correlations between the characteristics of the ignition system and flame propagation as well as cycle-to-cycle variations. Numerical results are compared to engine data in terms of in-cylinder pressure traces. The results show that an improved control over the energy released to the fluid surrounding the spark domain during the ignition process has beneficial effects on combustion stability. This allows extending the dilution tolerance for fuel/air mixtures. Although affected by cyclic variability, numerical results show good qualitative agreement with experimental data. The result is a simple but promising approach for relatively quick assessment of stability improvements from advanced and alternative ignition strategies.

Download Full-text

Potential of Ceria-Zirconia-Based Materials in Carbon Soot Oxidation for Gasoline Particulate Filters

Catalysts ◽

10.3390/catal10070768 ◽

2020 ◽

Vol 10 (7) ◽

pp. 768

Author(s):

Eleonora Aneggi ◽

Alessandro Trovarelli

Keyword(s):

Oxygen Vacancies ◽

Mixed Oxides ◽

Direct Injection ◽

Soot Oxidation ◽

Operating Conditions ◽

Gasoline Direct Injection ◽

Low Oxygen ◽

Engine Exhaust ◽

Partial Pressures ◽

Carbon Soot

ZrO2 and Ce0.8Zr0.2O2 mixed oxides were prepared and tested in the oxidation of carbon soot at different oxygen partial pressures and degrees of catalyst/soot contact to investigate their activity under typical gasoline direct injection (GDI) operating conditions. Under reductive atmospheres, generation of oxygen vacancies occurs in Ce0.8Zr0.2O2, while no reduction is observed on ZrO2. Both materials can oxidize carbon under high oxygen partial pressures; however, at low oxygen partial pressures, the presence of carbon can contribute to the reduction of the catalyst and formation of oxygen vacancies, which can then be used for soot oxidation, increasing the overall performance. This mechanism is more efficient in Ce0.8Zr0.2O2 than ZrO2, and depends heavily on the interaction and the degree of contact between soot and catalyst. Thus, the ability to form oxygen vacancies at lower temperatures is particularly helpful to oxidize soot at low oxygen partial pressures, and with higher CO2 selectivity under conditions typically found in GDI engine exhaust gases.

Download Full-text

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

Volume 2: Emissions Control Systems; Instrumentation, Controls, and Hybrids; Numerical Simulation; Engine Design and Mechanical Development ◽

10.1115/icef2018-9722 ◽

2018 ◽

Cited By ~ 1

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.

Download Full-text

Combustion Ionization for Detection of Misfire, Knock, and Sporadic Preignition in a Gasoline Direct Injection Engine

Journal of Energy Resources Technology ◽

10.1115/1.4043789 ◽

2019 ◽

Vol 141 (11) ◽

Cited By ~ 1

Author(s):

Samuel Ayad ◽

Swapnil Sharma ◽

Rohan Verma ◽

Naeim Henein

Keyword(s):

Pressure Transducer ◽

Direct Injection ◽

Operating Conditions ◽

Gasoline Direct Injection ◽

Ion Current ◽

Fuel Injector ◽

Direct Injection Engine ◽

Gasoline Direct Injection Engine ◽

Spark Plug ◽

Knock Sensor

Detection of combustion-related phenomena such as misfire, knock, and sporadic preignition is very important for the development of electronic controls needed for the gasoline direct injection engines to meet the production goals in power, fuel economy, and low emissions. This paper applies several types of combustion ionization sensors, and a pressure transducer that directly senses the in-cylinder combustion, and the knock sensor which is an accelerometer that detects the impact of combustion on engine structure vibration. Experimental investigations were conducted on a turbocharged four-cylinder gasoline direct injection engine under operating conditions that produce the above phenomena. One of the cylinders is instrumented with a piezo quartz pressure transducer, MSFI (multi-sensing fuel injector), a stand-alone ion current probe, and a spark plug applied to act as an ion current sensor. A comparison is made between the capabilities of the pressure transducer, ion current sensors, and the knock sensor in detecting the above phenomena. The signals from in-cylinder combustion sensors give more accurate information about combustion than the knock sensor. As far as the feasibility and cost of their application in production vehicles, the spark plug sensor and MSFI appear to be the most favorable, followed by the stand-alone mounted sensor which is an addition to the engine.

Download Full-text

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

Journal of Energy Resources Technology ◽

10.1115/1.4044763 ◽

2019 ◽

Vol 142 (4) ◽

Cited By ~ 7

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.

Download Full-text

Numerical Simulation of Knock Combustion in a Downsizing Turbocharged Gasoline Direct Injection Engine

Applied Sciences ◽

10.3390/app9194133 ◽

2019 ◽

Vol 9 (19) ◽

pp. 4133 ◽

Cited By ~ 1

Author(s):

Wang ◽

Zhang ◽

Wang ◽

Han ◽

Chen

Keyword(s):

Direct Injection ◽

Combustion Process ◽

Three Dimensional ◽

Operating Conditions ◽

Gasoline Direct Injection ◽

Valve Lift ◽

Fuel Droplets ◽

Gasoline Direct Injection Engine ◽

Auto Ignition ◽

Combustion Simulation

Engine knock has become the prime barrier to significantly improve power density and efficiency of the engines. To further look into the essence of the abnormal combustion, this work studies the working processes of normal combustion and knock combustion under practical engine operating conditions using a three-dimensional computation fluid dynamics (CFD) fluid software CONVERGE (Version 2.3.0, Convergent Science, Inc., Madison, USA). The results show that the tumble in the cylinder is gradually formed with the increase of the valve lift, enhances in the compression stroke and finally is broken due to the extrusion of the piston. The fuel droplets gradually evaporate and move to the intake side under the turbulent and high temperature in the cylinder. During the normal combustion process, the flame propagates faster on the intake side and it facilitates mixture in cylinder combustion. During the knock combustion simulation, the hotspots near the exhaust valve are observed, and the propagating detonation wave caused by multiple hotspots auto-ignition indicates significant effects on knock intensity of in-cylinder pressure.

Download Full-text