The Experts below are selected from a list of 7269 Experts worldwide ranked by ideXlab platform
Hasan Ustun Basaran - One of the best experts on this subject based on the ideXlab platform.
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Effects of application of variable valve timing on the Exhaust gas temperature improvement in a low-loaded diesel engine
Applied Thermal Engineering, 2017Co-Authors: Hasan Ustun Basaran, Osman Azmi OzsoysalAbstract:Engine manufacturers generally use aftertreatment systems to meet the strict emission criteria on automotive diesel engines. However, those systems opeRate inefficiently particularly at low-loaded cases of diesel engines since Exhaust gas temperatures at aftertreatment inlet remain below 250 °C. For those cases, variable valve timing (VVT) method can be applied to elevate Exhaust temperatures and improve aftertreatment emission conversion efficiency. Therefore, in this study, intake valve closing (IVC) timing is advanced and retarded sufficiently from the base condition on a low-loaded diesel engine to increase aftertreatment inlet Exhaust temperature above 250 °C. A specially designed computer program, Lotus Engine Simulation (LES), is utilized to model the diesel engine. Experimental data of a similar study is used for the validation of the simulation. Engine loading (taken as brake mean effective pressure (BMEP)) is kept constant at 2.5 bar by adjusting the fuel injection Rate. The results show that there is a considerable Exhaust temperature rise (up to 65 °C) at aftertreatment inlet with the method and it is adequate for effective aftertreatment performance (TExhaust > 250 °C). It is also seen that the increase on Exhaust temperature is due to the sudden reduction on volumetric efficiency (from 94% to 65%). Therefore, there is lower air induction into the cylinders and hence lower pumping losses which result in fuel-efficiency in the system. However, air Flow reduction also causes a sharp decrease on the Exhaust Flow Rate which affects the heat capacity of Exhaust gases negatively in the system.
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modelling the effect of intake valve closing timing on Exhaust thermal management of a turbocharged and intercooled diesel engine
Gemi ve Deniz Teknolojisi, 2016Co-Authors: Hasan Ustun BasaranAbstract:Emissions from diesel engines have become recently a significant problem due to their positive effect on global-warming. There are strict restrictions on emissions and low-emission diesel engines nowadays are required to be developed. One of the solution for reduced-emission diesel engines is to utilize Exhaust thermal management systems. However; these systems work efficiently mostly at temperatures above 250 oC and for diesel engines, especially at low speed and low load conditions, Exhaust gas temperatures are not generally higher than 250 oC. That not only leads to inefficient aftertreatment systems, but also insufficient emission reduction. Variable valve timing (VVT) can be used to achieve those high Exhaust gas temperatures by changing the opening and closing timings of the intake&Exhaust valves at any speed and any load. Therefore, the aim of this study is to try to increase the turbine exit temperature of a diesel engine above 250 oC at 2.50 bar brake mean effective pressure (bmep) and 1200 rpm engine speed condition by changing intake valve closing (IVC) timings. Diesel engine system is simulated by using Lotus Engine Simulation (LES) program. The model is then validated with experimental results. It is seen that Exhaust gas temperatures can be raised higher than 250 oC for the studied particular engine loading case when IVC is advanced or retarded. The method results in fuel consumption saving in comparison to nominal valve timing by decreasing the required fuel injection Rate for the constant engine loading. However, earlier and later closing of intake valve also causes Exhaust Flow Rate to drop off.
Osman Azmi Ozsoysal - One of the best experts on this subject based on the ideXlab platform.
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Effects of application of variable valve timing on the Exhaust gas temperature improvement in a low-loaded diesel engine
Applied Thermal Engineering, 2017Co-Authors: Hasan Ustun Basaran, Osman Azmi OzsoysalAbstract:Engine manufacturers generally use aftertreatment systems to meet the strict emission criteria on automotive diesel engines. However, those systems opeRate inefficiently particularly at low-loaded cases of diesel engines since Exhaust gas temperatures at aftertreatment inlet remain below 250 °C. For those cases, variable valve timing (VVT) method can be applied to elevate Exhaust temperatures and improve aftertreatment emission conversion efficiency. Therefore, in this study, intake valve closing (IVC) timing is advanced and retarded sufficiently from the base condition on a low-loaded diesel engine to increase aftertreatment inlet Exhaust temperature above 250 °C. A specially designed computer program, Lotus Engine Simulation (LES), is utilized to model the diesel engine. Experimental data of a similar study is used for the validation of the simulation. Engine loading (taken as brake mean effective pressure (BMEP)) is kept constant at 2.5 bar by adjusting the fuel injection Rate. The results show that there is a considerable Exhaust temperature rise (up to 65 °C) at aftertreatment inlet with the method and it is adequate for effective aftertreatment performance (TExhaust > 250 °C). It is also seen that the increase on Exhaust temperature is due to the sudden reduction on volumetric efficiency (from 94% to 65%). Therefore, there is lower air induction into the cylinders and hence lower pumping losses which result in fuel-efficiency in the system. However, air Flow reduction also causes a sharp decrease on the Exhaust Flow Rate which affects the heat capacity of Exhaust gases negatively in the system.
E Jiaqiang - One of the best experts on this subject based on the ideXlab platform.
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influence of structural and operating factors on performance degradation of the diesel particulate filter based on composite regeneration
Applied Thermal Engineering, 2017Co-Authors: E Jiaqiang, Bin Zhang, Jinke Gong, Wenhua Yuan, Xiaohuan ZhaoAbstract:Abstract In order to effectively investigate the effects of various factors on the DPF's performance deterioration, and obtain the primary influence factor, an efficient evaluation method is proposed in this work. Firstly, the maximum wall temperature and the pressure drop are taken as the evaluation indexes of DPF's performance deterioration (thermal aging and filter clogging) respectively, and the orthogonal experimental design is used for obtaining the simulation conditions of test cases. Then, the impacts of four structural factors (wall thickness, mean pore size, porosity and channel width) and five operating factors (Exhaust Flow Rate, Exhaust oxygen concentration, microwave power, catalytic additive mass concentration and deposited ash mass) on DPF's performance deterioration are evaluated by fuzzy membership grades and Euclidean grey relational grades, respectively. Finally, fuzzy grey relational analysis is employed to make a comprehensive evaluation. The results show that the wall thickness and the channel width have the most noticeable effect on filter clogging and thermal aging among all structural factors, respectively. Moreover, the deposited ash mass and the microwave power are the most important operating factors for filter clogging and thermal aging, respectively. This work offers us great reference value for optimizing DPF performances and improving its degradation resistance.
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effect analysis on pressure drop of the continuous regeneration diesel particulate filter based on no2 assisted regeneration
Applied Thermal Engineering, 2016Co-Authors: E Jiaqiang, Wei Zuo, Zhiqing Zhang, Qingguo Peng, Junxu Gao, Pham Minh HieuAbstract:Abstract In order to enhance the dynamic performance, fuel economy and reduce particulate emissions for a diesel engine, the key is to reduce the pressure drop of continuous regeneration-diesel particulate filter (CR-DPF) based on NO2-assisted regeneration. In this work, firstly, a mathematic model based on NO2-assisted regeneration is developed. Then, the effects of the Exhaust gas parameters and structural parameters of the CR-DPF on pressure drop in the NO2-assisted regeneration process are investigated and verified by experiments. Results show that the pressure drop is decreased under some conditions such as the modeRate increase of the low Exhaust Flow Rate, the reduction of the Exhaust temperature, the reduction of the NO2 concentration in the Exhaust gas and the increase of the channel wall thickness, while the pressure drop is increased under other conditions such as the mass ratio m(NO2)/m(soot) between the NO2 and the soot being less than its threshold in Exhaust gas, the increase of the filter length of the CR-DPF and the increase of the channel density when initial amount of the soot in filter is less than its threshold. Moreover, the O2 concentration in Exhaust gas has no effect on the pressure drop. Finally, the proper ranges of some key parameters for reducing pressure drop of the CR-DPF have been provided.
Bin Zhang - One of the best experts on this subject based on the ideXlab platform.
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influence of structural and operating factors on performance degradation of the diesel particulate filter based on composite regeneration
Applied Thermal Engineering, 2017Co-Authors: E Jiaqiang, Bin Zhang, Jinke Gong, Wenhua Yuan, Xiaohuan ZhaoAbstract:Abstract In order to effectively investigate the effects of various factors on the DPF's performance deterioration, and obtain the primary influence factor, an efficient evaluation method is proposed in this work. Firstly, the maximum wall temperature and the pressure drop are taken as the evaluation indexes of DPF's performance deterioration (thermal aging and filter clogging) respectively, and the orthogonal experimental design is used for obtaining the simulation conditions of test cases. Then, the impacts of four structural factors (wall thickness, mean pore size, porosity and channel width) and five operating factors (Exhaust Flow Rate, Exhaust oxygen concentration, microwave power, catalytic additive mass concentration and deposited ash mass) on DPF's performance deterioration are evaluated by fuzzy membership grades and Euclidean grey relational grades, respectively. Finally, fuzzy grey relational analysis is employed to make a comprehensive evaluation. The results show that the wall thickness and the channel width have the most noticeable effect on filter clogging and thermal aging among all structural factors, respectively. Moreover, the deposited ash mass and the microwave power are the most important operating factors for filter clogging and thermal aging, respectively. This work offers us great reference value for optimizing DPF performances and improving its degradation resistance.
Pham Minh Hieu - One of the best experts on this subject based on the ideXlab platform.
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effect analysis on pressure drop of the continuous regeneration diesel particulate filter based on no2 assisted regeneration
Applied Thermal Engineering, 2016Co-Authors: E Jiaqiang, Wei Zuo, Zhiqing Zhang, Qingguo Peng, Junxu Gao, Pham Minh HieuAbstract:Abstract In order to enhance the dynamic performance, fuel economy and reduce particulate emissions for a diesel engine, the key is to reduce the pressure drop of continuous regeneration-diesel particulate filter (CR-DPF) based on NO2-assisted regeneration. In this work, firstly, a mathematic model based on NO2-assisted regeneration is developed. Then, the effects of the Exhaust gas parameters and structural parameters of the CR-DPF on pressure drop in the NO2-assisted regeneration process are investigated and verified by experiments. Results show that the pressure drop is decreased under some conditions such as the modeRate increase of the low Exhaust Flow Rate, the reduction of the Exhaust temperature, the reduction of the NO2 concentration in the Exhaust gas and the increase of the channel wall thickness, while the pressure drop is increased under other conditions such as the mass ratio m(NO2)/m(soot) between the NO2 and the soot being less than its threshold in Exhaust gas, the increase of the filter length of the CR-DPF and the increase of the channel density when initial amount of the soot in filter is less than its threshold. Moreover, the O2 concentration in Exhaust gas has no effect on the pressure drop. Finally, the proper ranges of some key parameters for reducing pressure drop of the CR-DPF have been provided.