Ali Sürmen

Performance Characteristics of Sunflower Methyl Esters as Biodiesel

This study is devoted to determining performance characteristics of biodiesel as a diesel engine fuel. An engine performance test using sunflower methyl esters exhibited characteristics very similar to regular diesel. The test values obtained from a 2.5 lt. 4 cylinder Peugeot XD3p157 engine shows that torque values obtained by the two types of fuels are 5%–10% in favor of regular diesel. Obviously, power values will be the engine revolutions times this percentage with regular diesel. Specific fuel consumption, however, is better with biodiesel. This means that a better combustion characteristic is achieved with biodiesel, which compensates for its lower calorific value. Soot emissions are slightly less with biodiesel, as expected, due to the improvement in specific fuel consumption.

Experimental Investigation of the Natural Vortex Length in Tangential Inlet Cyclones

In this study, the natural vortex length has been investigated experimentally under the effects of inlet gas velocity, diameter, and insertion length of the vortex finder and surface friction in a special designed cyclone which has a double cylindrical body without cone. Experimental results show that, comparing to the other parameters, the height of the frictional surface and inlet gas velocity affect the natural vortex length considerably. The natural vortex length increases with the increase of inlet velocity and with the decrease of the height of the frictional surface. It was also observed that when the diameter of the vortex finder increases, the natural vortex length increases up to certain point and starts to decrease after that.

Theoretical and experimental investigation of effect of valve timing on volumetric efficiency in an IC engine

Volumetric efficiency is a typical parameter that is effected by almost all constructive, aerodynamic and thermal parameters through a simple or complicated relation. In this study, the effect of valve timing, which is a highly dynamic parameter, has been investigated. Beside the original one, thirteen new camshafts have been produced without changing the angles that valves are open. New camshafts are then produced by shifting the valve-open period. All camshafts are used to determine volumetric efficiency at various engine speeds.

Investigation of performance and emission characteristics of waste cooking oil as biodiesel in a diesel engine

Biodiesel is one of the most popular prospective alternative fuels and can be obtained from a variety of sources. Waste frying oil is one such source along with the various raw vegetable oils. However, some specific technical treatments are required to improve certain fuel properties such as viscosity and calorific value of the biodiesel being obtained from waste cooking oil methyl ester (WCOME). Various treatments are applied depending on the source and therefore the composition of the cooking oil. This research investigated the performance of WCOME as an alternative biofuel in a four-stroke direct injection diesel engine. An 8-mode test was undertaken with diesel fuel and five WCOME blends. The best compromise blend in terms of performance and emissions was identified. Results showed that energy utilization factors of the blends were similar within the range of the operational parameters (speed, load and WCOME content). Increasing biodiesel content produced slightly more smoke and NOx for a great majority of test points, while the CO and THC emissions were lower.

Development of a variable-profile cam to enhance the volumetric efficiency of IC engines

In this study, it is aimed to develop a new concept camshaft for continuously variable valve timing (CVVT). The concept is based on obtaining a curvilinear cam surface by integrating a number of conventional cam contours. Thirteen unworked camshafts, with arbitrary different contours, i.e., valve opening and closing times, were machined and tested on a four-stroke single-cylinder diesel engine to determine their volumetric efficiency at varied engine speeds. Then with suitable axial arrangement of these individual contours on a camshaft and integration of them, a single curvilinear cam surface was obtained. It is expected to get the same volumetric efficiency, with a ball contact follower when it follows a specific contour, as obtained when the specific cam of the same contour individually yielded. By giving an axial motion to the camshaft, allowing the follower to follow different contours, continuous variation of valve timing will be achieved.

Experimental investigation into performance characteristics of reversed flow cyclone separators

Cyclone separators have been extensively used both for particle sampling and particle removal from fluids, air or process gases in the field of air pollution control and in industry. In this experimental study, effects of inlet velocity, inlet shape and cyclone length on the cyclone collection efficiency and pressure losses were investigated. A new cyclone design without conical part and its performance were also presented. Experiments show that optimum inlet size and cyclone length can be found for better collection efficiency at a specified flow rate. Experimental results from the tests on the new cyclone are evaluated and compared with the results in conventional cyclone. Results show that the new cyclone gives better efficiency comparing to the conventional cyclone for the same cyclone diameter and inlet velocity.

Automation of a Gasoline Engine Test Bed

Abstract An instructional closed-loop computer-controlled gasoline engine test bed based on an IBM PC/AT computer has been designed and constructed for mechanical engineering curriculum. For the following engine variables, the testing, controlling and analysis of the gasoline engine by a computer program are possible: Cooling water and exhaust temperatures, inlet air and cooling water flowrates, engine speed and load, minimum and maximum throttle and braking positions.