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Sensitivity Analysis Study on Ethanol Partially Premixed Combustion

SAE International Journal of Engines

Lund University-Mehrzad Kaiadi, Bengt Johansson, Marcus Lundgren
Scania CV AB-John A. Gaynor
  • Journal Article
  • 2013-01-0269
Published 2013-04-08 by SAE International in United States
Partially Premixed Combustion (PPC) is a combustion concept which aims to provide combustion with low smoke and NOx with high thermal efficiency. Extending the ignition delay to enhance the premixing, avoiding spray-driven combustion and controlling the combustion temperature at an optimum level through use of suitable lambda and EGR levels have been recognized as key factors to achieve such a combustion. Fuels with high ignitability resistance have been proven to be a useful to extend the ignition delay. In this work pure ethanol has been used as a PPC fuel.The objective of this research was initially to investigate the required operating conditions for PPC with ethanol. Additionally, a sensitivity analysis was performed to understand how the required parameters for ethanol PPC such as lambda, EGR rate, injection pressure and inlet temperature influence the combustion in terms of controllability, stability, emissions (i.e. HC, CO, NOx and Soot) and combustion and thermodynamic efficiency.Investigations have been performed experimentally on a single cylinder heavy duty engine where each of the parameters swept one at time. The results showed that…
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Experimental Investigation on different Injection Strategies for Ethanol Partially Premixed Combustion

Lund University-Mehrzad Kaiadi, Bengt Johansson, Marcus Lundgren
Scania CV AB-John A. Gaynor
Published 2013-04-08 by SAE International in United States
Partially Premixed Combustion (PPC) is a combustion concept which aims to provide combustion with low smoke and NOx with high efficiency. Extending the ignition delay to enhance the premixing, avoiding spray-driven combustion and controlling the combustion temperature to optimum levels through use of suitable lambda and EGR levels, have been recognized as key factors to achieve such combustion. Fuels with high ignitability resistance have been proven to be a good mean to extend the ignition delay. In this work pure ethanol has been used as a PPC fuel.The objective of this research was to investigate a suitable injection strategy for PPC combustion fueled with ethanol. Extensive experimental investigations were performed on a single-cylinder heavy-duty engine. The number of injections for each cycle, timing of the injections and the ratio between different injection pulses was varied one at a time and the combustion behavior was investigated at medium and low loads. The engine performance was evaluated in terms of controllability, stability, combustion noise, emissions and different efficiencies. Additionally, a comparison between single and double-injection strategies was…
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Reducing Throttle Losses Using Variable Geometry Turbine (VGT) in a Heavy-Duty Spark-Ignited Natural Gas Engine

Lund Univ.-Mehrzad Kaiadi, Per Tunestal, Bengt Johansson
Published 2011-08-30 by SAE International in United States
Stoichiometric operation of Spark Ignited (SI) Heavy Duty Natural Gas (HDNG) engines with a three way catalyst results in very low emissions however they suffer from bad gas-exchange efficiency due to use of throttle which results in high throttling losses.Variable Geometry Turbine (VGT) is a good practice to reduce throttling losses in a certain operating region of the engine. VTG technology is extensively used in diesel engines; it is very much ignored in gasoline engines however it is possible and advantageous to be used on HDNG engine due to their relatively low exhaust gas temperature. Exhaust gas temperatures in HDNG engines are low enough (lower than 760 degree Celsius) and tolerable for VGT material. Traditionally HDNG are equipped with a turbocharger with waste-gate but it is easy and simple to replace the by-pass turbocharger with a well-matched VGT.By altering the geometry of the turbine housing, the area for exhaust gases can be adjusted and results in the desired torque. Because of this the turbo lag is very low and it has a low boost threshold.…
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Unburned Hydro Carbon (HC) Estimation Using a Self-Tuned Heat Release Method

Lund University-Mehrzad Kaiadi, Per Tunestal, Bengt Johansson
Published 2010-10-25 by SAE International in United States
An estimation model which uses the gross heat release data and the fuel energy to estimate the total amount of emissions and unburned Hydro Carbon (HC) is developed. Gross heat release data is calculated from a self-tuned heat release method which uses in-cylinder pressure data for computing the energy released during combustion. The method takes all heat and mass losses into account. The method estimates the polytropic exponent and pressure offset during compression and expansion using a nonlinear least square method. Linear interpolation of polytropic exponent and pressure offset is then performed during combustion to calculate the gross heat release during combustion. Moreover the relations between the emissions specifically HC and Carbon Monoxide (CO) are investigated. The model was validated with experimental data and promising results were achieved.
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How Hythane with 25% Hydrogen can Affect the Combustion in a 6-Cylinder Natural-gas Engine

SAE International Journal of Fuels and Lubricants

Lund Univ.-Mehrzad Kaiadi
Lund University-Per Tunestål, Bengt Johansson
  • Journal Article
  • 2010-01-1466
Published 2010-05-05 by SAE International in United States
Using alternative fuels like Natural Gas (NG) has shown good potentials on heavy duty engines. Heavy duty NG engines can be operated either lean or stoichiometric diluted with EGR. Extending Dilution limit has been identified as a beneficial strategy for increasing efficiency and decreasing emissions. However dilution limit is limited in these types of engines because of the lower burnings rate of NG. One way to extend the dilution limit of a NG engine is to run the engine on Hythane (natural gas + some percentage hydrogen). Previously effects of Hythane with 10% hydrogen by volume in a stoichiometric heavy duty NG engine were studied and no significant changes in terms of efficiency and emissions were observed.This paper presents results from measurements made on a heavy duty 6-cylinder NG engine. The engine is operated with NG and Hythane with 25% hydrogen by volume and the effects of these fuels on the engine performance are studied. Different experiments were designed and performed to investigate the parameters like knocking margin, dilution limit, lean limit, different efficiencies, emissions…
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Using Hythane as a Fuel in a 6-Cylinder Stoichiometric Natural-gas Engine

SAE International Journal of Fuels and Lubricants

Division of Combustion Engines, Lund University-Mehrzad Kaiadi, Per Tunestål, Bengt Johansson
  • Journal Article
  • 2009-01-1950
Published 2009-06-15 by SAE International in United States
Combination of right EGR rates with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark-ignited natural gas engines. With stoichiometric conditions a three way catalyst can be used which means that regulated emissions can be kept at very low levels. However dilution limit is limited in these types of engines because of the lower burnings rate of natural gas with higher EGR rates. One way to extend the dilution limit of a natural gas engine is to run the engine with Hythane (natural gas+ some percentage hydrogen). Previously benefits of hydrogen addition to a Lean Burn natural-gas fueled engine was investigated [1] however a complete study for stoichiometric operation was not performed.This paper presents measurements made on a heavy duty 6-cylinder natural gas engine. Three different experiments were designed and tested to investigate first of all if the engine encounters too severe knocking problems, second how and why, Hythane affect the running and finally how lean limit and dilution limit will be improved. The experiments…
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Closed-Loop Combustion Control Using Ion-current Signals in a 6-Cylinder Port-Injected Natural-gas Engine

Lund University-Mehrzad Kaiadi, Per Tunestål, Bengt Johansson
Published 2008-10-06 by SAE International in United States
High EGR rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark ignition engines. With stoichiometric conditions a three way catalyst can be used which means that regulated emissions can be kept at very low levels. Obtaining reliable spark ignition is difficult however with high pressure and dilution. There will be a limit to the amount of EGR that can be tolerated for each operating point. Open loop operation based on steady state maps is difficult since there is substantial dynamics both from the turbocharger and from the wall heat interaction. The proposed approach applies standard closed loop lambda control for controlling the overall air/fuel ratio. Furthermore, ion-current based dilution limit control is applied on the EGR in order to maximize EGR rate as long as combustion stability is preserved. The proposed control strategy has been successfully tested on a heavy duty 6-cylinder port injected natural gas engine and our findings show that 1.5-2.5 % units (depending on the operating points) improvement in…
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Closed-Loop Combustion Control for a 6-Cylinder Port-Injected Natural-gas Engine

SAE International Journal of Fuels and Lubricants

Lund University-Mehrzad Kaiadi, Per Tunestål, Bengt Johansson
  • Journal Article
  • 2008-01-1722
Published 2008-06-23 by SAE International in United States
High EGR rates combined with turbocharging has been identified as a promising way to increase the maximum load and efficiency of heavy duty spark ignition engines. With stoichiometric conditions a three way catalyst can be used which means that regulated emissions can be kept at very low levels. Obtaining reliable spark ignition is difficult however with high pressure and dilution. There will be a limit to the amount of EGR that can be tolerated for each operating point. Open loop operation based on steady state maps is difficult since there is substantial dynamics both from the turbocharger and from the wall heat interaction. The proposed approach applies standard closed loop lambda control for controlling the overall air/fuel ratio for a heavy duty 6-cylinder port injected natural gas engine. A closed loop load control is also applied for keeping the load at a constant level when using EGR. Furthermore, cylinder pressure based dilution limit control is applied on the EGR in order to keep the coefficient of variation at the desired level of 5%. This way…
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