Yazar "Calam, Alper" seçeneğine göre listele

Listeleniyor 1 - 5 / 5
  • [ X ]
    Öğe
    An Experimental Research on the Effects of Negative Valve Overlap on Performance and Operating Range in a Homogeneous Charge Compression Ignition Engine With RON40 and RON60 Fuels
    (Asme, 2020) Polat, Seyfi; Solmaz, Hamit; Uyumaz, Ahmet; Calam, Alper; Yilmaz, Emre; Yucesu, H. Serdar
    In this study, the effects of negative valve overlap (NVO) on homogenous charge compression ignition (HCCI) combustion and engine performance were experimentally investigated. A four stroke, single cylinder, port injection HCCI engine was operated at -16 deg crank angle (CA), -8 deg CA, and +8 deg CA valve overlap values and different lambda values and engine speeds at wide open throttle. RON40 and RON60 were used as test fuels in view of combustion and performance characteristics in HCCI mode. The variations of indicated mean effective pressure (IMEP), residual gas, CA50, indicated thermal efficiency (ITE), indicated specific fuel consumption (ISFC), maximum pressure rise rate (MPRR) and ringing intensity (RI) were observed on HCCI combustion. The results showed that NVO caused to trap residual gases in the combustion chamber. Hot residual gases showed heating and dilution effect on HCCI combustion. Combustion was retarded with the presence of residual gas at -16 deg CA NVO. Test results showed that higher imep and maximum in-cylinder pressure were obtained with RON60 according to RON40. As expected, CA50 was obtained later with RON60 compared to RON40 due to more resistance of auto-ignition. RON60 residual gas prevented the rapid and sudden combustion due to higher heat capacity of charge mixture. RI decreased with the usage of RON60 compared to RON40. Significant decrease was seen on RI with RON60 especially at lower lambda values. It was seen that HCCI combustion can be controlled with NVO and operating range of HCCI engines can be extended.
  • [ X ]
    Öğe
    Estimation of the COVIMEP variation in a HCCI engine
    (2020) Polat, Seyfi; Solmaz, Hamit; Calam, Alper; Yılmaz, Emre
    In this study, variation of the COVIMEP was tried to be predicted by using the artificial neural network method for 4-stroke, 4- cylinder, direct injection and supercharged HCCI engine experimental data obtained by using n-heptane fuel at 60 oC intake air temperature, 1000 rpm engine speed at different inlet air intake pressure. Intake air inlet pressure and lambda were used as input data in artificial neural network model. The COVIMEP value was used as the target. Three layers and five neurons were used to construct the network using the Levenberg-Marquardt algorithm. Correlation between targets and outputs for teaching, accuracy and testing were obtained as 0.97989, 0.9504 and 0.91644, respectively. Total correlation factor was found as 0.96983. As a result of the study, it was seen that the stored data and the estimated COVIMEP data were compatible.
  • [ X ]
    Öğe
    Estimation of the COVIMEP Variation in a HCCI Engine
    (Gazi Univ, 2020) Polat, Seyfi; Solmaz, Hamit; Calam, Alper; Yilmaz, Emre
    In this study, variation of the COVIMEP was tried to be predicted by using the artificial neural network method for 4-stroke, 4-cylinder, direct injection and supercharged HCCI engine experimental data obtained by using n-heptane fuel at 60 degrees C intake air temperature, 1000 rpm engine speed at different inlet air intake pressure. Intake air inlet pressure and lambda were used as input data in artificial neural network model. The COVIMEP value was used as the target. Three layers and five neurons were used to construct the network using the Levenberg-Marquardt algorithm. Correlation between targets and outputs for teaching, accuracy and testing were obtained as 0.97989, 0.9504 and 0.91644, respectively. Total correlation factor was found as 0.96983. As a result of the study, it was seen that the stored data and the estimated COVIMEP data were compatible.
  • [ X ]
    Öğe
    Investigation of usability of the fusel oil in a single cylinder spark ignition engine
    (Elsevier B.V., 2015) Calam, Alper; Solmaz, Hamit; Uyumaz, Ahmet; Polat, Seyfi; Yılmaz, Emre; Içingür, Yakup
    In order to decrease the dependency on petrol-originated energy resources, the utilization of different energy resources in internal combustion engines has been the center of interest of researchers. The main renewable alternative combustible species are ethanol, methanol, hydrogen, biodiesel, and biogas. On the other hand, appearing as a by-product during alcohol production via fermentation, the fusel oil is another alternative energy resource which can be used in internal combustion engines. Containing high alcohols, fusel oil is dark brown colored alcohol mixture, and has a strong odor. The calorific value of fusel oil close to other alternative combustible types ones and the limited number of researches on utilization of fusel oil, an alcohol derivative, in internal combustion engines constitute the base of this research. In this study, the effects of the mixture of unleaded gasoline and fusel oil on engine torque, brake specific fuel consumption and exhaust emissions in a single cylinder, spark ignition engine having port-type fuel infection system at various engine speeds and loads have been investigated. As a result of research carried out, as the amount of fusel oil in mixture increased, the improvements have been observed in engine torque at all of engine speeds and loads compared to pure unleaded gasoline. It has been determined that the brake specific fuel consumption and carbon monoxide (CO) and hydro-carbon (HC) emissions have increased while nitrogen-oxide (NOx) emissions have decreased. © 2014 Energy Institute. Published by Elsevier Ltd. All rights reserved.
  • [ X ]
    Öğe
    Mapping of an HCCI engine using negative valve overlap strategy
    (Taylor and Francis Inc., 2020) Polat, Seyfi; Solmaz, Hamit; Yılmaz, Emre; Calam, Alper; Uyumaz, Ahmet; Yücesu, Hüseyin Serdar
    In order to control combustion phasing and extend operation range of homogeneous charged compression ignition (HCCI) engines, several techniques such as controlling inlet air temperature and pressure, using alternative fuels, variable compression ratio, supercharging, etc. have been applied. Among them, variable valve mechanism received much attention to extend HCCI operating range and control autoignition. Mode switching between spark plug ignition (SI) to HCCI has been started to use widely because of limited operation range of the HCCI mode. To control of an engine switching combustion modes between SI and HCCI, embedded system needs parametrical control maps of the engine. In this study, operation range, air excess ratio, torque and thermal efficiency maps of an HCCI engine using negative valve overlap (NVO) strategy were obtained and additionally the effects of NVO on HCCI combustion in view of in-cylinder temperature, heat release rate, effective thermal efficiency, combustion phasing, and exhaust emissions were investigated. Also, variation of CO, HC, and NOx emissions were evaluated at different valve overlaps. Three different valve overlap including +8, ?8, and ?16 CA were used in the experiments. Test results showed that in-cylinder pressure and heat release decreased with NVO. The test engine could run without knocking by application of NVO. It was seen that operating range of HCCI extended with NVO. It was also found that effective thermal efficiency increased with ?16ºCA valve overlap compared to other valve timings.