Cenk Sayin

Comparison of performance and combustion parameters in a heavy-duty diesel engine fueled with iso-butanol/diesel fuel blends

This study discusses the suitability of iso-butanol/diesel fuel blends as an alternative fuel and determines their effects on the performance and combustion characteristics of a heavy-duty diesel engine. For this purpose, various iso-butanol/diesel fuel blends containing 5%, 10% and 15% iso-butanol were prepared in volume basis and tested in a turbo-charged, six-cylinder direct injection diesel engine at the speed of 1400 rpm and three different loads (150, 300 and 450 Nm). The results indicate that when the test engine was fueled with the iso-butanol/diesel fuel blends, the brake thermal efficiency decreased, while the brake specific fuel consumption increased with proportion to using conventional diesel fuel. When iso-butanol/diesel fuel blends were used, the heat release rate, the peak cylinder gas pressure slightly increased compared to the neat diesel fuel use. Although the iso-butanol/diesel fuel blends have poor performance values at partial engine loads, their fuel properties affected the combustion and injection characteristics. They caused reductions in CO, NOx emissions and smoke opacity. However, unburned HC emission slightly increased.

Numerical Evaluation by Models of Load and Spark Timing Effects on the In-Cylinder Heat Transfer of a SI Engine

The aim of this study is to examine numerically the effects of spark timing and load parameters on the in-cylinder heat transfer of a SI engine by using experimental engine test data. For the investigation, a four-stroke, air-cooled, single-cylinder SI engine was tested at different spark timings and loads at a single engine speed of 2000 rpm. Woschni, Hohenberg, and Han models were employed to estimate the in-cylinder heat transfer coefficient in the case of different test conditions because of being favorable models on the SI engine operations. The evaluations show that the in-cylinder heat transfer characteristics of the air-cooled SI engine strongly depend on the load while they slightly depend on the spark timing.

Effects of thermal barrier coating on the performance and combustion characteristics of a diesel engine fueled with biodiesel produced from waste frying cottonseed oil and ultra-low sulfur diesel

ABSTRACT In this study, the top surfaces of piston and valves of a four-strokes and direct-injection diesel engine have been coated—with no change in the compression ratio—with a 100 μm of NiCrAl lining layer via plasma spray method and this layer has later been coated with main coating material with a mixture of 88% of ZrO2, 4% of MgO and 8% of Al2O3 (400 μm). Then, after the engine-coating process, ultra-low sulfur diesel (ULSD) as base fuels and its blend with used frying cottonseed oil derived biodiesel in proportion of 20%, volumetrically, have been tested in the coated engine and data of combustion and performance characteristics on full load and at different speeds have been noted. The results, which were compared with those obtained by uncoated-engine operation, showed that thermal efficiency increased, and engine noise reduced. Cylinder gas pressure values obtained from the diesel engine which has been coated with thermal barriers have been found to be somewhat higher than those of the uncoated-engine. Also, maximum pressure values measured in both engines and under the same experimental conditions through the use of test fuel have been obtained after TDC. Moreover, heat release rate and heat release have occurred earlier in the coated-engine. NOx emissions were increased while CO and HC emissions were remained almost the same with a little bit decrease.

Analysis of Combustion Characteristics of a LHR-STD Diesel Engine Fuelled with Biofuel and Diesel Fuel

It is important to efficiently use of alternative fuel in CI (compression ignition) engine, because of the lack of energy shortages will be in the present and coming years. Therefore this study, the top surfaces of the piston, exhaust and inlet valves of a four-stroke, direct injection, single cylinder CI engine was coated with a mixture of insulation materials by use of plasma spray method. After that, determine of combustion characteristics of standard (STD) CI engine and the low heat rejection (LHR) CI engine were tested under the same experimental conditions and the same experimental setup, fuelled with the WB20, WB100 and DF fuels. The results of both engines are compared with each other so that analyze how this modification is effect on the combustion parameters. Experimental results showed that LHR diesel engine generally is partly similar to STD diesel engine in terms of the knock density, mass burning rate, average gas temperature, velocity of heat transfer, coefficient of heat transfer and total heat transfer.