The Experts below are selected from a list of 73800 Experts worldwide ranked by ideXlab platform
Xiaosong Zhang - One of the best experts on this subject based on the ideXlab platform.
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power management strategy for a parallel hybrid power Gas Engine heat pump system
Applied Thermal Engineering, 2017Co-Authors: Xiaoming Wan, Liang Cai, Jie Yan, Tao Chen, Xiaosong ZhangAbstract:Abstract Hybrid-power Gas Engine heat pump (HPGHP) system is a novel air conditioning system, which has two power sources, the Gas Engine and dual-use motor respectively. Based on the experimental tests on HPGHP system, the key component models of the system have been established in this paper. In order to keep the Gas Engine always running with high thermal efficiency and reducing the Gas consumption, a preliminary rule-based control strategy is first described in the paper to distribute the power sources. Then, for obtaining better fuel economy, the equivalent Gas consumption minimization mathematical models and power balance principle are established. At last, the equivalent Gas consumption minimization strategy is put forward and the torque curves of the Engine and motor are optimized under different operating modes, to minimize the equivalent Gas consumption. The results show that the Gas Engine can always run in economical zone with high thermal efficiency above 0.25 in different working modes. The Gas consumed rate reaches the minimum value of 284.62 g/(kW h), 286.93 g/(kW h), and 296.6 g/(kW h) in mode C, mode D and mode L, when the compressor speed is 950 rpm, 1450 rpm, and 2150 rpm, respectively. The average PER of HPGHP system is 0.894, 0.969, and 1.049 in mode C, mode D and mode L, respectively.
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simulation and validation of a hybrid power Gas Engine heat pump
International Journal of Refrigeration-revue Internationale Du Froid, 2015Co-Authors: Wenxiu Jiang, Jieyue Wang, Weiwei Deng, Xiaosong ZhangAbstract:Abstract Hybrid-power Gas Engine heat pump (HPGHP) combines hybrid power technology with Gas Engine heat pump, which can keep the Gas Engine working in the economical zone. In this paper, a steady-state model of the HPGHP in heating condition has been established, the optimal torque curve control strategy is proposed to distribute power between the Gas Engine and battery pack. The main operating parameters of the HPGHP system are simulated on Matlab/Simulink and validated by experimental data, such as operating temperature, coefficient of performance (COP), fuel-consumed rate, etc. Heating capacity and COP of the heating pump system are validated under different ambient temperatures and water flow rates. The simulation and experiment results shows acceptable agreement, the maximum difference is respectively 8.9%, 5.9%, 9.5% and 8.2% for Engine torque, motor torque, reclaimed heat and fuel-consumed rate. Based on the simulation results, HPGHP has the lowest fuel-consumed rate of 283 g (kWh)−1 at Engine speed of 3000 rpm; the PER of HPGHP system is about 15.9% and 11.4% higher than the GHP under the same load in Mode C and D.
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performance study of parallel type hybrid power Gas Engine driven heat pump system
Energy and Buildings, 2013Co-Authors: Yanwei Wang, Liang Cai, Xiaosong ZhangAbstract:Abstract This paper analyzes the operating principle and the advantages of the parallel-type hybrid-power Gas Engine-driven heat pump system (PHGHP) and builds test systems to test the performance of the system in the heating conditions and cooling conditions. PHGHP used heat pump system's cooling capacity, heat capacity, fuel-consumed flow, fuel consumed-rate, thermal efficiency and reclaimed heat as the economic analysis parameters. In addition, this paper puts forward the concept of the equivalent fuel-consumed flow and the equivalent output power of Engine. The test results show, the speed and torque of Gas Engine which used the baseline control strategy and combined with a Gas Engine optimization curve control strategy are always in the designated economic. Fuel-consumed flow changes in 280–340 g (kW h)−1. With compressor speed increasing, the drive system thermal efficiency is maintained between 0.23 and 0.28.
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modeling and optimization matching on drive system of a coaxial parallel type hybrid power Gas Engine heat pump
Energy, 2013Co-Authors: Jieyue Wang, Liang Cai, Yanwei Wang, Xiaosong ZhangAbstract:A steady-state model of the coaxial parallel-type drive system is established to discuss the matching relations between the drive system and the dynamic load of the compressor. In order to improve energy conversion efficiency, this paper raises a torque control model, establishes the optimization scheme of the drive system and puts forward the switching law of the Hybrid-power Gas Engine Heat Pump (HPGHP). In addition, a new method of transmission ratio design is put forward to optimize the power matching of the drive system based on the load model of probability distribution. The simulation results show that the transmission ratios are respectively 3.2, 2 and 1.5 in three modes. At last, the energy management scheme of battery packs has been established. The results show that the state of the charge (SOC) can keep constant in one cycle when the ratio between the Mode L operation time and the Mode C operation time is about 1.38. And the variation range of SOC depends on the operation time of Mode D in one cycle.
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analysis on energy saving effect and environmental benefit of a novel hybrid power Gas Engine heat pump
International Journal of Refrigeration-revue Internationale Du Froid, 2013Co-Authors: Yanwei Wang, Liang Cai, Xiaowei Shao, Gaolong Jin, Xiaosong ZhangAbstract:Abstract Taking a novel hybrid-power Gas Engine heat pump as an example, fuel-consumed rate, fuel-consumed flow, fuel conversion efficiency and life cycle assessment were used to analyze energy-saving effect and natural Gas environmental benefits on human health, ecosystem quality and resource consumption through contrast with electric power consumption model. The test results show that the fuel conversion efficiency under different operating conditions of HPGHP is higher than conventional GHP under the same load. Besides, from the total indicator, scores on resource consumption is the highest. Gaseous product is mainly CO 2 and other carbon or sulfur oxide Gases are discharged in form of negative or water body, which means the use of natural Gas effectively control the pollution Gas emissions. At last, concept of environmental benefit time was established; the result shows that HPGHP can embody better environmental benefits than Gas heat pump when running more than 1778 h.
Arif Hepbasli - One of the best experts on this subject based on the ideXlab platform.
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Advanced exergoeconomic analysis of a Gas Engine heat pump (GEHP) for food drying processes
Energy Conversion and Management, 2015Co-Authors: Aysegul Gungor, Huseyin Gunerhan, George Tsatsaronis, Arif HepbasliAbstract:Exergetic and exergoeconomic analyses are often used to evaluate the performance of energy systems from the thermodynamic and economic points of view. While a conventional exergetic analysis can be used to recognize the sources of inefficiencies, the so-called advanced exergy-based analysis is convenient for identifying the real potential for thermodynamic improvements and the system component interactions by splitting the exergy destruction and the total operating cost within each component into endogenous/exogenous and unavoidable/avoidable parts. In this study for the first time an advanced exergoeconomic analysis is applied to a Gas-Engine-driven heat pump (GEHP) drying system used in food drying for evaluating its performance along with each component. The advanced exergoeconomic analysis shows that the unavoidable part of the exergy destruction cost rate within the components of the system is lower than the avoidable part. The most important components based on the total avoidable costs are drying ducts, the condenser and the expansion valve. The inefficiencies within the condenser could particularly be improved by structural improvements of the whole system and the remaining system components. Finally, it can be concluded that the internal design changes play a more essential role in determining the cost of each component.
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Exergoeconomic analyses of a Gas Engine driven heat pump drier and food drying process
Applied Energy, 2011Co-Authors: Aysegul Gungor, Zafer Erbay, Arif HepbasliAbstract:Exergoeconomic analysis of a pilot scale Gas Engine driven heat pump (GEHP) drying system is performed based on the experimental values using Exergy, Cost, Energy and Mass (EXCEM) analysis method in this study. The performance of the drying system components is discussed, while the important system components are determined to improve the system efficiency. The performance of the drying process is also analyzed for three different medicinal and aromatic plants from the exergoeconomic point of view. A comprehensive parametric study is conducted to investigate the effect of varying dead (reference) state temperatures on exergoeconomic performance parameters for both drying system components and drying process. The correlations between the performance parameters and dead state temperatures are developed. The results have indicated that the dead state temperature affects the performance parameters, particularly the drying process parameters. Rising the dead state temperature leads to an increase in the exergy efficiencies of the drying process and a decrease in the ratio of the thermodynamic loss rate to the capital cost values in a polynomial form. values of the drying process are obtained to be very higher compared to those of the drying system components.
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exergoeconomic analyses of a Gas Engine driven heat pump drier and food drying process
Applied Energy, 2011Co-Authors: Aysegul Gungor, Zafer Erbay, Arif HepbasliAbstract:Abstract Exergoeconomic analysis of a pilot scale Gas Engine driven heat pump (GEHP) drying system is performed based on the experimental values using Exergy, Cost, Energy and Mass (EXCEM) analysis method in this study. The performance of the drying system components is discussed, while the important system components are determined to improve the system efficiency. The performance of the drying process is also analyzed for three different medicinal and aromatic plants from the exergoeconomic point of view. A comprehensive parametric study is conducted to investigate the effect of varying dead (reference) state temperatures on exergoeconomic performance parameters for both drying system components and drying process. The correlations between the performance parameters and dead state temperatures are developed. The results have indicated that the dead state temperature affects the performance parameters, particularly the drying process parameters. Rising the dead state temperature leads to an increase in the exergy efficiencies of the drying process and a decrease in the ratio of the thermodynamic loss rate to the capital cost ( R ˙ ex ) values in a polynomial form. R ˙ ex values of the drying process are obtained to be very higher compared to those of the drying system components.
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exergetic analysis and evaluation of a new application of Gas Engine heat pumps gehps for food drying processes
Applied Energy, 2011Co-Authors: Aysegul Gungor, Zafer Erbay, Arif HepbasliAbstract:In this study, three medicinal and aromatic plants (Foeniculum vulgare, Malva sylvestris L. and Thymus vulgaris) were dried in a pilot scale Gas Engine driven heat pump drier, which was designed, constructed and installed in Ege University, Izmir, Turkey. Drying experiments were performed at an air temperature of 45 °C with an air velocity of 1 m/s. In this work, the performance of the drier along with its main components is evaluated using exergy analysis method. The most important component for improving the system efficiency is found to be the Gas Engine, followed by the exhaust air heat exchanger for the drying system. An exergy loss and flow diagram (the so-called Grassmann diagram) of the whole drying system is also presented to give quantitative information regarding the proportion of the exergy input dissipated in the various system components, while the sustainability index values for the system components are calculated to indicate how sustainability is affected by changing the exergy efficiency of a process. Gas Engine, expansion valve and drying ducts account for more than 60% amount of exergy in the system. The exergetic efficiency values are in the range of 77.68-79.21% for the heat pump unit, 39.26-43.24% for the Gas Engine driven heat pump unit, 81.29-81.56% for the drying chamber and 48.24-51.28% for the overall drying system.
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a review of Gas Engine driven heat pumps gehps for residential and industrial applications
Renewable & Sustainable Energy Reviews, 2009Co-Authors: Arif Hepbasli, Zafer Erbay, Filiz Icier, Neslihan Colak, Ebru HanciogluAbstract:Abstract This study reviews Gas Engine-driven heat pump (GEHP) systems for residential and industrial applications in terms of energetic and exergetic aspects for the first time to the best of the authors’ knowledge. These systems are novel heat pump systems (one of today's promising new technologies). Although the first investigations had been performed at late 1970s, the first merchandized GEHP was produced and introduced in the market in 1985. Gradually, it has become widespread all over the world for various purposes. Main application of GEHPs are for space and water heating/cooling purposes. However, they can be integrated to industrial applications, especially to drying processes. In this study, historical development of GEHP systems was briefly given first. Next, the operation of these systems was described, while studies conducted on them were reviewed and presented in tabulated forms. GEHPs were then modeled for performance evaluation purposes by using energy and exergy analysis methods. Finally, an illustrative example was given, while the results obtained were discussed. In addition, a new project on integration of GEHP systems to food drying processes in Turkey initiated by the authors was introduced. It is expected that this comprehensive study will be very beneficial to everyone involved or interested in the energetic and exergetic design, simulation, analysis and performance of assessment of GEHP systems.
Liang Cai - One of the best experts on this subject based on the ideXlab platform.
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power management strategy for a parallel hybrid power Gas Engine heat pump system
Applied Thermal Engineering, 2017Co-Authors: Xiaoming Wan, Liang Cai, Jie Yan, Tao Chen, Xiaosong ZhangAbstract:Abstract Hybrid-power Gas Engine heat pump (HPGHP) system is a novel air conditioning system, which has two power sources, the Gas Engine and dual-use motor respectively. Based on the experimental tests on HPGHP system, the key component models of the system have been established in this paper. In order to keep the Gas Engine always running with high thermal efficiency and reducing the Gas consumption, a preliminary rule-based control strategy is first described in the paper to distribute the power sources. Then, for obtaining better fuel economy, the equivalent Gas consumption minimization mathematical models and power balance principle are established. At last, the equivalent Gas consumption minimization strategy is put forward and the torque curves of the Engine and motor are optimized under different operating modes, to minimize the equivalent Gas consumption. The results show that the Gas Engine can always run in economical zone with high thermal efficiency above 0.25 in different working modes. The Gas consumed rate reaches the minimum value of 284.62 g/(kW h), 286.93 g/(kW h), and 296.6 g/(kW h) in mode C, mode D and mode L, when the compressor speed is 950 rpm, 1450 rpm, and 2150 rpm, respectively. The average PER of HPGHP system is 0.894, 0.969, and 1.049 in mode C, mode D and mode L, respectively.
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performance study of parallel type hybrid power Gas Engine driven heat pump system
Energy and Buildings, 2013Co-Authors: Yanwei Wang, Liang Cai, Xiaosong ZhangAbstract:Abstract This paper analyzes the operating principle and the advantages of the parallel-type hybrid-power Gas Engine-driven heat pump system (PHGHP) and builds test systems to test the performance of the system in the heating conditions and cooling conditions. PHGHP used heat pump system's cooling capacity, heat capacity, fuel-consumed flow, fuel consumed-rate, thermal efficiency and reclaimed heat as the economic analysis parameters. In addition, this paper puts forward the concept of the equivalent fuel-consumed flow and the equivalent output power of Engine. The test results show, the speed and torque of Gas Engine which used the baseline control strategy and combined with a Gas Engine optimization curve control strategy are always in the designated economic. Fuel-consumed flow changes in 280–340 g (kW h)−1. With compressor speed increasing, the drive system thermal efficiency is maintained between 0.23 and 0.28.
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modeling and optimization matching on drive system of a coaxial parallel type hybrid power Gas Engine heat pump
Energy, 2013Co-Authors: Jieyue Wang, Liang Cai, Yanwei Wang, Xiaosong ZhangAbstract:A steady-state model of the coaxial parallel-type drive system is established to discuss the matching relations between the drive system and the dynamic load of the compressor. In order to improve energy conversion efficiency, this paper raises a torque control model, establishes the optimization scheme of the drive system and puts forward the switching law of the Hybrid-power Gas Engine Heat Pump (HPGHP). In addition, a new method of transmission ratio design is put forward to optimize the power matching of the drive system based on the load model of probability distribution. The simulation results show that the transmission ratios are respectively 3.2, 2 and 1.5 in three modes. At last, the energy management scheme of battery packs has been established. The results show that the state of the charge (SOC) can keep constant in one cycle when the ratio between the Mode L operation time and the Mode C operation time is about 1.38. And the variation range of SOC depends on the operation time of Mode D in one cycle.
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analysis on energy saving effect and environmental benefit of a novel hybrid power Gas Engine heat pump
International Journal of Refrigeration-revue Internationale Du Froid, 2013Co-Authors: Yanwei Wang, Liang Cai, Xiaowei Shao, Gaolong Jin, Xiaosong ZhangAbstract:Abstract Taking a novel hybrid-power Gas Engine heat pump as an example, fuel-consumed rate, fuel-consumed flow, fuel conversion efficiency and life cycle assessment were used to analyze energy-saving effect and natural Gas environmental benefits on human health, ecosystem quality and resource consumption through contrast with electric power consumption model. The test results show that the fuel conversion efficiency under different operating conditions of HPGHP is higher than conventional GHP under the same load. Besides, from the total indicator, scores on resource consumption is the highest. Gaseous product is mainly CO 2 and other carbon or sulfur oxide Gases are discharged in form of negative or water body, which means the use of natural Gas effectively control the pollution Gas emissions. At last, concept of environmental benefit time was established; the result shows that HPGHP can embody better environmental benefits than Gas heat pump when running more than 1778 h.
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a novel parallel type hybrid power Gas Engine driven heat pump system
International Journal of Refrigeration-revue Internationale Du Froid, 2007Co-Authors: Xiaosong Zhang, Liang CaiAbstract:This paper presents a novel concept to integrate a heat pump system and a power system which form a hybrid-power Gas Engine-driven heat pump (HPGHP) system. The power system of the HPGHP system includes an Engine, a motor, a set of battery packs, a continuous variable transmission device and a power-control module. The Engine in the power system is capable of operating constantly with high thermal efficiency and low emissions during the four different operating modes: for operating mode A, the ICE powers directly to match the compressor's demand load by throttling the natural-Gas flow or adjusting the speed of the ICE, correspondingly the battery packs are disengaged and the ICE operates alone; for operating mode B, the ICE operates in the unique condition with the lowest fuel consumption ratio, meanwhile, the battery packs discharge to provide the supplementary power by the power-control module; for operating mode C, the ICE operates in the unique condition with the lowest fuel consumption ratio, and the redundant power provided by the ICE is converted by the motor to charge the battery packs, here, the motor is used as a generator; for operating mode D, the ICE is disengaged and the battery pack is used alone. Simulation results of the power system showed that for a conventional Gas Engine-driven heat pump (GHP) system the maximum and minimum thermal efficiencies of the power system are 33% and 22%, respectively; compared with the conventional GHP system, the power system in the novel HPGHP system has superior performance with the maximum and minimum thermal efficiencies of 37% and 27%, respectively.
Aysegul Gungor - One of the best experts on this subject based on the ideXlab platform.
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Advanced exergoeconomic analysis of a Gas Engine heat pump (GEHP) for food drying processes
Energy Conversion and Management, 2015Co-Authors: Aysegul Gungor, Huseyin Gunerhan, George Tsatsaronis, Arif HepbasliAbstract:Exergetic and exergoeconomic analyses are often used to evaluate the performance of energy systems from the thermodynamic and economic points of view. While a conventional exergetic analysis can be used to recognize the sources of inefficiencies, the so-called advanced exergy-based analysis is convenient for identifying the real potential for thermodynamic improvements and the system component interactions by splitting the exergy destruction and the total operating cost within each component into endogenous/exogenous and unavoidable/avoidable parts. In this study for the first time an advanced exergoeconomic analysis is applied to a Gas-Engine-driven heat pump (GEHP) drying system used in food drying for evaluating its performance along with each component. The advanced exergoeconomic analysis shows that the unavoidable part of the exergy destruction cost rate within the components of the system is lower than the avoidable part. The most important components based on the total avoidable costs are drying ducts, the condenser and the expansion valve. The inefficiencies within the condenser could particularly be improved by structural improvements of the whole system and the remaining system components. Finally, it can be concluded that the internal design changes play a more essential role in determining the cost of each component.
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Exergoeconomic analyses of a Gas Engine driven heat pump drier and food drying process
Applied Energy, 2011Co-Authors: Aysegul Gungor, Zafer Erbay, Arif HepbasliAbstract:Exergoeconomic analysis of a pilot scale Gas Engine driven heat pump (GEHP) drying system is performed based on the experimental values using Exergy, Cost, Energy and Mass (EXCEM) analysis method in this study. The performance of the drying system components is discussed, while the important system components are determined to improve the system efficiency. The performance of the drying process is also analyzed for three different medicinal and aromatic plants from the exergoeconomic point of view. A comprehensive parametric study is conducted to investigate the effect of varying dead (reference) state temperatures on exergoeconomic performance parameters for both drying system components and drying process. The correlations between the performance parameters and dead state temperatures are developed. The results have indicated that the dead state temperature affects the performance parameters, particularly the drying process parameters. Rising the dead state temperature leads to an increase in the exergy efficiencies of the drying process and a decrease in the ratio of the thermodynamic loss rate to the capital cost values in a polynomial form. values of the drying process are obtained to be very higher compared to those of the drying system components.
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exergoeconomic analyses of a Gas Engine driven heat pump drier and food drying process
Applied Energy, 2011Co-Authors: Aysegul Gungor, Zafer Erbay, Arif HepbasliAbstract:Abstract Exergoeconomic analysis of a pilot scale Gas Engine driven heat pump (GEHP) drying system is performed based on the experimental values using Exergy, Cost, Energy and Mass (EXCEM) analysis method in this study. The performance of the drying system components is discussed, while the important system components are determined to improve the system efficiency. The performance of the drying process is also analyzed for three different medicinal and aromatic plants from the exergoeconomic point of view. A comprehensive parametric study is conducted to investigate the effect of varying dead (reference) state temperatures on exergoeconomic performance parameters for both drying system components and drying process. The correlations between the performance parameters and dead state temperatures are developed. The results have indicated that the dead state temperature affects the performance parameters, particularly the drying process parameters. Rising the dead state temperature leads to an increase in the exergy efficiencies of the drying process and a decrease in the ratio of the thermodynamic loss rate to the capital cost ( R ˙ ex ) values in a polynomial form. R ˙ ex values of the drying process are obtained to be very higher compared to those of the drying system components.
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exergetic analysis and evaluation of a new application of Gas Engine heat pumps gehps for food drying processes
Applied Energy, 2011Co-Authors: Aysegul Gungor, Zafer Erbay, Arif HepbasliAbstract:In this study, three medicinal and aromatic plants (Foeniculum vulgare, Malva sylvestris L. and Thymus vulgaris) were dried in a pilot scale Gas Engine driven heat pump drier, which was designed, constructed and installed in Ege University, Izmir, Turkey. Drying experiments were performed at an air temperature of 45 °C with an air velocity of 1 m/s. In this work, the performance of the drier along with its main components is evaluated using exergy analysis method. The most important component for improving the system efficiency is found to be the Gas Engine, followed by the exhaust air heat exchanger for the drying system. An exergy loss and flow diagram (the so-called Grassmann diagram) of the whole drying system is also presented to give quantitative information regarding the proportion of the exergy input dissipated in the various system components, while the sustainability index values for the system components are calculated to indicate how sustainability is affected by changing the exergy efficiency of a process. Gas Engine, expansion valve and drying ducts account for more than 60% amount of exergy in the system. The exergetic efficiency values are in the range of 77.68-79.21% for the heat pump unit, 39.26-43.24% for the Gas Engine driven heat pump unit, 81.29-81.56% for the drying chamber and 48.24-51.28% for the overall drying system.
Bengt Johansson - One of the best experts on this subject based on the ideXlab platform.
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cfd simulations of pre chamber jets mixing characteristics in a heavy duty natural Gas Engine
JSAE SAE 2015 International Powertrains Fuels & Lubricants Meeting, 2015Co-Authors: Ashish Shah, Per Tunestal, Bengt JohanssonAbstract:The effect of pre-chamber volume and nozzle diameter on performance of pre-chamber ignition device in a heavy duty natural Gas Engine has previously been studied by the authors. From the analysis of recorded pre- and main chamber pressure traces, it was observed that a pre-chamber with a larger volume reduced flame development angle and combustion duration while at a given pre-chamber volume, smaller nozzle diameters provided better ignition in the main chamber. The structure of pre-chamber jet and its mixing characteristics with the main chamber charge are believed to play a vital role, and hence CFD simulations are performed to study the fluid dynamic aspects of interaction between the pre-chamber jet and main chamber charge during the period of flame development angle, i.e. before main chamber ignition. It has been observed that jets from a larger pre-chamber penetrates through the main chamber faster due to higher momentum and generates turbulence in the main chamber earlier. At a given pre-chamber volume, smaller nozzle diameter causes higher velocity jet also causing high turbulence built up and better distribution of active species from the pre-chamber into the main chamber. (Less)
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applicability of ionization current sensing technique with plasma jet ignition using prechamber spark plug in a heavy duty natural Gas Engine
SAE 2012 International Powertrains Fuels & Lubricants Meeting, 2012Co-Authors: Ashish Shah, Per Tunestal, Bengt JohanssonAbstract:This article deals with study of ionization current sensing technique's signal characteristics while operating with pre-chamber spark plug to achieve plasma jet ignition in a 6 cylinder 9 liter turbo-charged natural Gas Engine under EGR and excess air dilution. Unlike the signal with conventional spark plug which can be divided into distinct chemical and thermal ionization peaks, the signal with pre-chamber spark plug shows a much larger first peak and a negligible second peak thereafter. Many studies in past have found the time of second peak coinciding with the time of maximum cylinder pressure and this correlation has been used as an input to combustion control systems but the absence of second peak makes application of this concept difficult with pre-chamber spark plug. However, it has been observed that the first peak is very strong and does not deteriorate much even under lean operation and hence ion current signal integral can be used to calculate real time combustion stability parameters for combustion control systems. The correlation between the coefficient of variation (COV) of indicated mean effective pressure (IMEP) and ion current integral for operation at 5, 12 and 18 bar IMEP load under stoichiometric and diluted operation with EGR and excess air is presented in this article. (Less)
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closed loop combustion control using ion current signals in a 6 cylinder port injected natural Gas Engine
SAE International Powertrains Fuels and Lubricants Congress, 2008Co-Authors: Mehrzad Kaiadi, Per Tunestal, Bengt JohanssonAbstract: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 Brake Efficiency can be achieved. (Less)
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closed loop combustion control for a 6 cylinder port injected natural Gas Engine
SAE International Journal of Fuels and Lubricants, 2008Co-Authors: Mehrzad Kaiadi, Per Tunestal, Bengt JohanssonAbstract: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 confirms that the EGR ratio is kept at its maximum stable level all times. Pumping losses decrease due to the further opening of the throttle, thereby the Gas exchange efficiency improves and since the regulator keeps track of the changes the Engine all the time operates in a stable region. Our findings show that excellent steady-state performance can be achieved using closed-loop combustion control for keeping the EGR level at the highest level while the stability level is still good enough. (Less)
