Jehad Yamin

Effect of combustion duration on the performance and emission characteristics of a spark ignition engine using hydrogen as a fuel

Abstract The deteriorating quality of air due to exhaust emissions and the increasing number of motor vehicles in the world, is sending alarming waves throughout the world to try to do something to cut off or significantly reduce these emissions in order to save our planet. Scientists have found that hydrogen presents the best and unprecedented solution to this problem, for its superior combustion qualities and availability. This paper discusses analytically one aspect of combustion i.e. combustion duration and how it is affected by an engine’s operating parameters like compression ratio, equivalence ratio, spark plug location, spark timing and engine speed, and how it affects an engine’s performance parameters like brake specific fuel consumption, brake mean effective pressure, thermal efficiency, as well as emission characteristics.

PERFORMANCE SIMULATION OF A FOUR-STROKE ENGINE WITH VARIABLE STROKE-LENGTH AND COMPRESSION RATIO

The engine consists of a coupled four-bar, slider-crank and inverted slider-crank mechanisms. The variations in stroke length and compression ratio are obtained through varying the location of the pivot of the four-bar rocker arm. The engine power characteristics are based on the power cycle of the piston inside the cylinder. Several pivot locations are considered giving a range of stroke lengths and corresponding compression ratios. A simulation model is developed and verified with experimental results from the literature for both constant and variable-stroke engines. The simulation results clearly indicate the advantages and utility of variable-stroke engines in fuel-economy issues.

Comparative performance of spark ignition engine using blends of various methanol percentages with low octane number gasoline

This study investigates the effect of methanol addition to low octane number gasoline, in terms of calorific value, octane number, compression ratio at knocking and engine performance. Locally produced gasoline (octane number = 87) was blended with five different percentages of methanol, namely 5%, 10%, 15%, 20% and 25% on volume basis. The properties of the respective fuel blends were first determined. Then they were tested in an engine. It was found that the octane number of gasoline increases continuously and linearly with methanol percentages in gasoline. Hence, methanol is an effective compound for increasing the value of the octane number of gasoline. Also, it was found that the engine performance improves as the percentage of methanol increases in the blend within the range studied.

Second-law analysis of an LPG-powered 4-stroke SI engine under variable stroke length and compression ratio

A second-law analysis of an LPG-powered, 4-stroke, single-cylinder, water-cooled, variable stroke length spark-ignition engine was carried out to assess the engines energy efficiency. The engine was simulated at each stroke length/compression ratio combination. The second law of thermodynamics with the aid of the first law represents the results of entropy generation, reversible work output and exergy destruction of combustion processes of propane fuel. This work shows that, from the second-law analysis point of view, lowering the bore-to-stroke ratio increases the fuel availability and minimises the destruction of thermodynamic availability in LPG combustion. It also minimises the availability transfer due to heat and improves the availability transfer due to work.

Performance comparison of a CI engine using diesel and biodiesel fuels and a magnetic fuel conditioner

ABSTRACT An experimental testing on the relative change of a four-stroke, multi-cylinder, direct injection, water-cooled compression ignition engine using both petrodiesel and biodiesel under the influence of a magnetic field was conducted. The engine was tested using pure petrodiesel (as reference fuel), pure biodiesel and their blends. This was done with and without the magnetic effect under fixed full load and variable speed conditions. Results showed that biodiesel is less influenced with the presence of the magnetic flux than diesel. Further, it was shown that engine performance enhancement is better with biodiesel than diesel without the use of a magnetic field.

The performance of hydrogen-powered 4-stroke SI engine using locally designed fuel regulator

In this work, the performance of a spark ignition engine powered with hydrogen fuel was studied and compared with gasoline fuel. Hydrogen fuel was used, using a locally made stainless steel gaseous regulator which was designed and installed in engine. This regulator was located between the engine and the hydrogen fuel cylinder, and it is triggered by the suction pressure and hence it keeps the fuel supply lines open under negative pressure only, which exists under no leak conditions and when the engine is running. It was found that the engine runs smoothly with the regulator in place. Further, it was found that the brake power and the volumetric efficiency of the engine drop down when the engine is powered by hydrogen, while the specific fuel consumption is drastically improved (by almost one-third) when hydrogen is used as a fuel. Finally, the thermal efficiency remains almost the same in both cases of fuels.

Relative Change in SI Engine Power and Economy with Variable Valve Timing: Simulation and ANOVA Analysis

In this research, a comparison between the performance of Ricardo E6/T variable compression ratio engine was conducted at constant and variable valve timing. This was done at three different speeds. The inlet and exhaust valves timing was varied and the performance was tested using specialized software. Results showed strong dependency of engine power and economy on valve timing and lift for all speeds. Further, higher lifts and durations are favorable for good power and the opposite are favorable for good economy. Valve overlap is affecting the engine power and economy in opposite direction as other factors.

Exergy analysis of biodiesel fueled direct injection CI engines

ABSTRACT This paper discusses the results of the first and second law analysis of a 4-cylinder, 4-stroke, Water-cooled, naturally aspirated, Direct injection diesel engine using the conventional petro-diesel as well as biodiesel made from waste cooking oil. This was done using the dynamometer test setup. The engine speed was limited to 2250 rpm (maximum range is 3000 rpm) due to excessive engine vibration. The test was carried out at full engine throttle. At first, the oil was collected and chemically treated and converted to biodiesel. Then, after servicing the engine, it was tested using the conventional petro-diesel used in Jordan and the base performance was recorded. Then, biodiesel was used and tested under similar conditions and the performance parameters were recorded. Finally, the first and second law parameters were calculated and compared. It was found that Biodiesel has 10% lower heating value on weight basis compared with petro-diesel. Petro-diesel showed minimum specific fuel consumption of 295 g/kW-h with compared with 348 g/kW-h for biodiesel at 22 rps. Maximum torque was 44.8 N-m obtained at 20 rps for biodiesel and 43.25 N-m at 25 rps for petro-diesel. Shaft availability increased from −14% to 10% for low and high speeds, respectively, for biodiesel, while availability lost to coolant was 10–15% higher for petro-diesel fuel.

Relative performance of a direct ignition diesel engine using biodiesel as fuel under Magnetic Fuel Conditioner

This paper discusses the effect of using waste-cooking-oil-biodiesel with/without the use of Magnetic Fuel Conditioner (MFC) on the performance and emission characteristics of a 4-stroke, direct injection, water-cooled compression ignition engine at full load. Waste cooking oil obtained from the Faculty of Engineering and Technology cafeteria at the University of Jordan was converted to biodiesel through the process of transesterification. The product was first tested for its required properties and compared with those for petrodiesel. Then the engine was run with pure diesel and biodiesel to set the reference performance. After that, the MFC was installed and the same experiment was repeated on both fuels. The engine speed was varied between 1000 to 2500 rpm. Higher values were not possible due to excessive engine vibration and leakage in the exhaust. It was found that brake torque, brake power, brake mean effective pressure and the thermal efficiency of diesel fuel performed better than biodiesel, while with the effect of MFC, both fuels performed much better. Whereas, the brake specific fuel consumption for diesel fuel was lower than biodiesel, while with the effect of magnet, both fuels showed improvement in the reduction of MFC. Furthermore, it was concluded that there was a favorable effect of using MFC on engine exhaust emissions.

The Performance of a Modified Al-Doura Pool Gasoline

A simulation study was conducted on a four-stroke, water-cooled, spark ignition engine using fuels produced by Al-Doura Oil Refinery. The fuels used were the unmodified Al-Doura Pool (April Formulae) and the enhanced pool formulae (called S1 and S3). First, the fuel properties were experimentally measured. Then the engine performance and emission characteristics were studied. Results showed improvement in most of the fuel properties such as calorific value, sulfur content, ON, gum content, and energy density. On the engine side, the brake power, torque, thermal efficiency, brake specific fuel consumption, and sulfur dioxide levels improved, while heat loss and NOx emissions increased.