Browsing by Author "Kaltakkiran, Galip"

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Design and Control of Intelligent Cooling System for IC Engine
(IEEE, 2017) Kaleli, Aliriza; Kaltakkiran, Galip; Dumlu, Ahmet; Ayten, Kagan Koray
The engine cooling systems in the commercial vehicles have not developed as the other control systems despite the technological improvements. Additionally, researchers in the automotive industry and the universities have focused on the power production and the combustion. Therefore, the thermal management of internal combustion engines, which has the same importance, does not taken into consideration sufficiently. However, optimum management of heat transfer system in the engines has an important effect on many parameters such as the engine performance, lubrication quality, exhaust emissions and fuel efficiency. It is necessary to define the engine cooling fluid temperature and flow rate profiles, and to follow them sensitively by a controller system to be designed. In this paper, it is aimed to design and to produce a thermal management system for internal combustion engines in order to ensure optimal distribution of the heat transfer. The electrically driven coolant pump and DC motor controlled valve is considered as control inputs. Additionally, robust control approach based on lumped parameter control oriented model of engine cooling system is presented. Finally, the proposed and traditional engine cooling systems are compared by means of exhaust emission values.
Exergy Analysis and Optimization of Multiple Injection Parameters of a Diesel Engine with Taguchi Method
(Taylor & Francis Inc, 2023) Guner, Erdogan; Kaltakkiran, Galip; Bakirci, Kadir; Ceviz, M. Akif
Multiple injection parameters have a significant effect on performance and emission formation in diesel engines. This study presents the optimization of these parameters with Taguchi method for different engine operating conditions. The experiments were conducted using four injections per cycle named Pilot1 (P1), Pilot2 (P2), Main (M), and Post (Po). The input parameters considered were injection timings and fuel quantities for each injection, while the output parameters were brake specific fuel consumption (BSFC) and nitrogen oxides (NOx) emissions. According to the results, the analysis of variance (ANOVA) shows that the durations of the P2 (D_P2) and Po (D_Po) and the start of the Main (SOI M) injection are very significant on BSFC and NOx emissions as independent of the engine speed. Based on contribution ratios at 1750 rpm and 2250 rpm operating conditions, D_Po is the most effective parameter on BSFC with 47.28% and 51.30%, while D_P2 has the greatest impact on NOx emissions with 37.96% and 61.80%, respectively. It is found from the optimization model obtained by using the Signal/Noise (S/N) ratios that injecting 5% of the total fuel in the post-injection phase could simultaneously improve BSFC and NOx emissions. Furthermore, the optimization model generally reduces heat loss exergy, exhaust exergy, and exergy destruction compared to the experimental values.
Instantaneous Energy Balance and Performance Analysis During Warm Up Period of a Spark Ignition Engine Under Several Thermal Energy Management Strategies
(Pergamon-Elsevier Science Ltd, 2022) Kaltakkiran, Galip; Ceviz, M. Akif; Bakirci, Kadir
Significant improvements can be obtained through different thermal energy management systems (TEMS) in internal combustion engines during warm up period. When the engine thermal energy management system works correctly, it ensures that the engine components are cooled exactly as needed, which is important in energy consumption and harmful exhaust emissions production. Additionally, thanks to the reduced warm up time, friction losses are reduced, after-treatment performance is increased, comfort conditions are improved in the passenger compartment, and the windshield quickly clears ice and condensation. However, the effects of the designed engine TEMSs on the energy balance during the warm up period should be well known. For this purpose, an experimental setup was established for not only the averages of the effects of different thermal strategies established as commonly done in the literature, but also the changes during the whole warm up process were analyzed. Then, three different TEMS were compared, and the effects of energy losses on each other were revealed. Results have shown that the warm up time can be reduced by 30 % with different engine TEMS, and thus, specific fuel consumption and CO emission can be reduced at different levels under several engine operating conditions. It was observed that when the engine coolant was not sent to the oil cooler heat exchanger during the warm up period, the thermostat opening time decreased from 252 s to 218 s. Moreover, it has been observed that the engine can reach steady state operating conditions approximately 10 % faster when the thermal energy is transferred from the exhaust gases, where a significant part of the fuel energy is lost, to the cooling water during the warm-up period.
A Novel Ignition Timing Strategy to Regulate the Energy Balance During the Warm Up Phase of an Si Engine
(Elsevier, 2023) Koksal, Huseyin; Ceviz, Mehmet Akif; Yakut, Kenan; Kaltakkiran, Galip; Ozakin, Ahmet Numan
The warm up characteristics of an engine have a significant impact on engine performance and exhaust emissions. In SI engines, the light-off performance of the catalytic converter is also important. One of the methods used to shorten the light off time of the catalytic converter is to retard the ignition time. When the ignition time is retarded, the temperature of the exhaust gases increases. However, in this case, the warm up performance of the engine itself may be adversely affected. In this study, firstly, the effects of ignition timing on the energy balance during the warm up period in an SI test engine were revealed. Then, a novel ignition timing strategy was proposed in order to increase the temperature of the exhaust gases, and not to reduce the engine performance. The novel ignition timing strategy working on the principle of sequentially advanced and retarded ignition at certain intervals during the warm up period provides several advantages. When the novel ignition strategy is applied, the energy loss through the exhaust gas was increased up to 7.2% for several operating conditions, while the reduction in engine performance is eliminated. Moreover, 20% reduction in NO emission has been achieved.
The Performance Improvement of Direct Injection Engines in Cold Start Conditions Integrating with Phase Change Material: Energy and Exergy Analysis
(Elsevier, 2021) Kaltakkiran, Galip; Ceviz, Mehmet Akif
The cold start problem is still one of the most significant drawbacks of diesel engines, especially in cold climates despite all technological improvements of fuel injection and control systems. Starting diesel engines becomes more difficult at low ambient air and engine block temperatures. Moreover, the production of pollutant exhaust emissions increases during the cold start and warm-up period of the engine. In this study, the thermal energy storage system (TES) with phase change materials (PCMs) has been proposed to improve the cold start and warm-up performance and exhaust emission characteristics of diesel engines. The waste heat from the engine main coolant using as the heat source is transferred to TES with integrated PCM after the warm-up period of the engine for heat storage. Then, the latent and sensible heat stored in PCM is transferred to the engine manifold to increase the temperature of intake air during cold start. The experiments have been conducted under low dead state temperature (approximate to 6 degrees C) conditions of the engine block and ambient. The experimental and energy-exergy comparison analysis results show that the cold start cranking period, CO and HC exhaust emission performances have improved by approximately 68.2%, 27.5% and 44% compared to classical engine system with the use of a designed TES, respectively. The efficiency of the strategy of increasing the intake air temperature by designing a PCM-based TES is supported by energy and exergy comparison analysis. Thermal efficiency and exergy efficiency improved in the range of 1.02%-7.45% and 0.9%-9.63%, respectively. These improvements show that the performance of a diesel engine under cold start conditions can be improved with a PCM-supported TES system.