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Henein, Naeim A.
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Smart Spark Plug for Proper Combustion Timing in Gasoline Engines and Detection of Misfire and Knock

Detroit Engineered Products (DEP) Inc.-Kamal Assaad
Wayne State University-Naeim A. Henein
  • Technical Paper
  • 2020-01-0790
To be published on 2020-04-14 by SAE International in United States
Internal combustion engines are required to achieve production goals of better fuel economy, improved fuel economy and reduced emissions in order to meet the current and future stringent standards. To achieve these goals, it is essential to control the combustion process using an in-cylinder combustion sensor and a system that produces a feedback signal to the ECU. This paper presents a system based on combustion ionization that includes a newly developed smart spark plug capable of sensing the whole combustion process. A unique feature of the smart spark plug system is its ability to sense the early stages of combustion and produce a complete ion current signal that accurately identifies and can be used for the control of the start of combustion. This is not the case for the conventional spark plug where the start of combustion cannot be determined from the ion current signal because its early part is distorted or completely overshadowed by the strong electromagnetic field produced by the spark ignition system. In addition to its ability to detect and control the…
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Simulation and Comparison of Autoignition of Homogeneous Fuel/Air Mixtures and Sprays in Diesel Engines

US Army TARDEC-Peter Schihl
Wayne State University-Umashankar Mohan Chandra Joshi, Manan Jyotin Trivedi, Ziliang Zheng, Naeim A. Henein
Published 2016-04-05 by SAE International in United States
All previous correlations of the ignition delay (ID) period in diesel combustion show a positive activation energy, which means that shorter ID periods are achieved at higher charge temperatures. This is not the case in the autoignition of most homogeneous hydrocarbons-air mixtures where they experience the NTC (Negative Temperature Coefficient ) regime in the intermediate temperature range, from about 800 K to 1000 K). Here, the autoignition reactions slow down and longer ID periods are experienced at higher temperatures. Accordingly the global activation energy for the autoignition reactions of homogeneous mixtures should vary from positive to negative values. In this paper, the discrepancy in the autoignition of a homogeneous charge and a heterogeneous charge is investigated. 3-D computer simulations of the physical and chemical processes in the combustion of fuel sprays in a diesel engine showed that this discrepancy is caused by the variations in the equivalence ratio of the first ignitable site in the spray with charge temperature. This finding has been validated by the simulation of autoignition of a homogeneous mixture at different…
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Characteristics of Ion Current Signals in Compression Ignition and Spark Ignition Engines

SAE International Journal of Engines

Cummins Inc.-Ashish Gupta
The British Univ. in Egypt-Ahmed Abdel-Rehim
  • Journal Article
  • 2010-01-0567
Published 2010-04-12 by SAE International in United States
Ion current sensors have been considered for the feedback electronic control of gasoline and diesel engines and for onboard vehicles powered by both engines, while operating on their conventional cycles or on the HCCI mode. The characteristics of the ion current signal depend on the progression of the combustion process and the properties of the combustion products in each engine. There are large differences in the properties of the combustible mixture, ignition process and combustion in both engines, when they operate on their conventional cycles. In SI engines, the charge is homogeneous with an equivalence ratio close to unity, ignition is initiated by an electric spark and combustion is through a flame propagating from the spark plug into the rest of the charge. In diesel engines, the charge is heterogeneous with equivalence ratios that vary from zero to infinity, gas pressures are much higher than the pressures in gasoline engines, autoignition starts the combustion process in a premixed charge followed by combustion controlled by mixing and diffusion processes.This paper examines the sources of ionization in…
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Impact of A/F Ratio on Ion Current Features Using Spark Plug with Negative Polarity

SAE International Journal of Passenger Cars - Electronic and Electrical Systems

Benha University, Egypt-Ahmed A. Abdel-Rehim
Wayne State University-Naeim A. Henein
  • Journal Article
  • 2008-01-1005
Published 2008-04-14 by SAE International in United States
The increasing interest and requirement for improved electronic engine control during the last few decades, has led to the implementation of several different sensor technologies. The process of utilizing the spark plug as a combustion probe to monitor the different combustion related parameters such as knock, misfire, Ignition timing, and air-fuel ratio have been the subject of research for some time now.The air-fuel ratio is one of the most important engine operating parameters that has an impact on the combustion process, engine-out emissions, fuel economy, indicated mean effective pressure and exhaust gas composition and temperature. Furthermore, air-fuel ratio affects the ion produced during flame kernel initiation and post flame propagation. In this paper, an investigation is made to determine the effect of air-fuel ratio on ion current, using gasoline and methane under different spark plug designs and engine operating conditions. The ion current is produced by using a negative bias and proved to contain enough information about the air-fuel ratio.
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Transient Fluid Flow and Heat Transfer in the EGR Cooler

SAE International Journal of Engines

US Army, TARDEC-Walter Bryzik
Wayne State University-Radu Florea, Dinu Taraza, Naeim A. Henein
  • Journal Article
  • 2008-01-0956
Published 2008-04-14 by SAE International in United States
EGR is a proven technology used to reduce NOx formation in both compression and spark ignition engines by reducing the combustion temperature. In order to further increase its efficiency the recirculated gases are subjected to cooling. However, this leads to a higher load on the cooling system of the engine, thus requiring a larger radiator. In the case of turbocharged engines the large variations of the pressures, especially in the exhaust manifold, produce a highly pulsating EGR flow leading to non-steady-state heat transfer in the cooler. The current research presents a method of determining the pulsating flow field and the instantaneous heat transfer in the EGR heat exchanger. The processes are simulated using the CFD code FIRE (AVL) and the results are subjected to validation by comparison with the experimental data obtained on a 2.5 liter, four cylinder, common rail and turbocharged diesel engine.
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Particulate Matter Characterization Studies in an HSDI Diesel Engine under Conventional and LTC Regime

SAE International Journal of Engines

General Electric-Yusuf Poonawala
US Army TARDEC-Walter Bryzik
  • Journal Article
  • 2008-01-1086
Published 2008-04-14 by SAE International in United States
Several mechanisms are discussed to understand the particulate matter (PM) characterization in a high speed, direct injection, single cylinder diesel engine using low sulfur diesel fuel. This includes their formation, size distribution and number density. Experiments were conducted over a wide range of injection pressures, EGR rates, injection timings and swirl ratios, therefore covering both conventional and low temperature combustion regimes. A micro dilution tunnel was used to immediately dilute a small part of the exhaust gases by hot air. A Scanning Mobility Particle Sizer (SMPS) was used to measure the particulate size distribution and number density. Particulate mass was measured with a Tapered Element Oscillating Microbalance (TEOM). Analysis was made of the root cause of PM characterization and their relationship with the combustion process under different operating conditions. PM increased with an increase in EGR in conventional combustion regime and decreased with increase in EGR under the Low Temperature Combustion (LTC) regime. The size distribution and number density shows more complex trends. The particulate formation was broadly divided into nucleation and accumulation modes and…
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Ion Current in a Spark Ignition Engine using Negative Polarity on Center Electrode

Benha University-Ahmed A. Abdel-Rehim
Wayne State University-Naeim A. Henein
Published 2007-04-16 by SAE International in United States
Most of the previous research on flame ionization in spark ignition engines applied positive polarity on the spark plug center electrode, referred to as positively biased probe. In this paper an investigation is made to determine the characteristics of the ion current signal with negatively biased probe. The factors that contribute to the second ion current peak, reported to be missing with negative polarity, are investigated. Experiments were conducted on a research single-cylinder, spark ignition engine and the negative polarity is applied by a SmartFire Plasma Ignition system. The effect of different spark plug designs and engine operating parameters on the amplitude and timing of each of the two ion current peaks is determined. The results indicated that, with negative polarity, the cathode area is one of the main factors that contribute to the amplitude of the ion current signal, particularly the second peak.
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Simulation-Based Cold-Start Control Strategy for a Diesel Engine with Common Rail Fuel System at Different Ambient Temperatures

US Army Tank-Automotive RDE Center (TARDEC)-Walter Bryzik
Wayne State University-Lurun Zhong, Naeim A. Henein
Published 2007-04-16 by SAE International in United States
A new tool has been used to arrive at appropriate split injection strategy for reducing the cranking period during the cold start of a multi-cylinder engine at decreasing ambient temperatures. The concept behind this tool is that the combination of different injection parameters that produce the highest IMEP should be able to improve the cold startability of the diesel engine. In this work the following injection parameters were considered: 1) injection timing, 2) split injection fraction, 3) dwell time and 4) total fuel mass injected per cycle. A commercial engine cyclic simulation code has been modified for diesel engine cycle simulation at lower ambient temperatures. The code was used to develop IMEP control maps. The maps were used to identify the parameters that would give the best IMEP. The strategies that have been identified have been validated experimentally in a multi-cylinder diesel engine equipped with a common rail fuel injection system. The simulation-based strategy proved to be very effective in improving cold start of the diesel engine at ambient temperature as low as -10°C. At…
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Engine Friction Model for Transient Operation of Turbocharged, Common Rail Diesel Engines

U.S. Army, TARDEC-Walter Bryzik
Wayne State University-Dinu Taraza, Naeim A. Henein, Radu Ceausu
Published 2007-04-16 by SAE International in United States
The simulation of I.C. Engines operation, especially during transients, requires a fairly accurate estimation of the internal mechanical losses of the engine. The paper presents generic friction models for the main friction components of the engine (piston-ring-liner assembly, bearings and valve train), considering geometry of the engine parts and peculiarities of the corresponding lubrication processes. Separate models for the mechanical losses introduced by the injection system, oil and water pumps are also developed. All models are implemented as SIMULINK modules in a complex engine simulation code developed in SIMULINK and capable to simulate both steady state and transient operating conditions. Validation is achieved by comparison with measurements made on a four cylinder, common rail diesel engine, on a test bench capable to run controlled transients.
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Lower Temperature Limits for Cold Starting of Diesel Engine with a Common Rail Fuel Injection System

US Army Tank-Automotive RDE Center (TARDEC)-Walter Bryzik
Wayne State University-Lurun Zhong, Steve Gruenewald, Naeim A. Henein
Published 2007-04-16 by SAE International in United States
One of the most challenging problems in diesel engines is to reduce unburned HC emissions that appear as (white smoke) during cold starting. In this paper the research is carried out on a 4-cylinder diesel engine with a common rail fuel injection system, which is able to deliver multiple injections during cold start. The causes of combustion failure at lower temperature limits are investigated theoretically by considering the rate of heat release. The results of this clearly indicate that in addition to low cranking engine speed, heat transfer and blow-by losses at lower ambient temperatures, fuel injection events would contribute to the failure of combustion. Also, combustion failure takes place when the compression temperature is lower than some critical value. Based on these results, split-main injection strategy was applied during engine cold starting and validated by experiments in a cold room at lower ambient temperatures.
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