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Showing 4 results for Zareei

J. Zareei, A. Rohani, Wan Mohd,
Volume 8, Issue 1 (3-2018)

To improve the engine performance and reduce emissions, factors such as changing ignition and injection timing along with converting of port injection system to direct injection in SI(spark-ignited) engines and hydrogen enrichment to CNG fuel at WOT conditions have a great importance. In this work, which was investigated experimentally (for CNG engine) and theoretically (for combustion Eddy Break-Up model and turbulence model is used) in a single- cylinder four-stroke SI engine at various engine speeds (2000-6000 rpm in 1000 rpm intervals), injection timing (130-210 crank angle(CA) in 50 CA intervals), ignition timing (19-28 CA in 2 degree intervals), 20 bar injection pressure and five hydrogen volume fraction 0% to 50% in the blend of HCNG. The results showed that fuel conversion efficiency, torque and power output were increased, while duration of heat release rate was shortened and found to be advanced. NOx emission was increased with the increase of hydrogen addition in the blend and the lowest NOx was obtained at the lowest speed and retarded ignition timing, hence 19° before top dead center. 

Dr Javad Zareei, Prof Mohamad Hasn Aghakhani, Mr Saeed Ahmadipour,
Volume 9, Issue 3 (9-2019)

Changing the compression ratio and presence of turbocharger are two important issues, affecting on performance, and exhaust emissions in internal combustion engines. To study the functional properties and exhaust emissions in regards to compression ratio at different speeds, the numerical solution of the governing equations on the fluid flow inside the combustion chamber and the numerical solution of one-dimensional computational fluid dynamics with the GT-Power software carried out. The diesel engine was with a displacement of 6.4 Lit and Turbocharged six-cylinder. In this engine was chosen, the compression ratio between 15: 1 and 19: 1 with intervals of one unit and the range of engine speed was from 800 to 2400 rpm. The results showed that by the presence of a turbocharger and changing the compression ratio from 17: 1 to 19: 1, the braking power and torque increased by about 56.24% compared to the non-turbocharged engine. In addition, was reduced the brake specific fuel consumption due to higher power output. The amount of CO and HC emissions decreases based on the reduction of the compression ratio compared to the based case, and the NOX value increases due to the production of higher heat than turbocharged engines. The overall results showed that the turbocharged engine with a 19: 1 compression ratio has the best performance and pollution characteristics.
Javad Zareei, Saeed Ahmadi,
Volume 10, Issue 3 (9-2020)

In internal combustion engines, the turbocharger and alternative fuels are two important factors affecting engine performance and exhaust emission. In this investigation, a one-dimensional computational fluid dynamics with GT-Power software was used to simulate a six-cylinder turbocharged diesel engine and the naturally aspirated diesel engine to study the performance and exhaust emissions with alternative fuels. The base fuel (diesel), methanol, ethanol, the blend of diesel and ethanol, biodiesel and decane was used. The results showed that decane fuel in the turbocharged engine has more brake power and torque (about 3.86%) compared to the base fuel. Also, the results showed that the turbocharger reduces carbon monoxide and hydrocarbon emissions, and biodiesel fuel has the least amount of carbon monoxide and hydrocarbon among other fuels. At the same time, the lowest NOX emission was obtained by decane fuel. As a final result can be demonstrated that the decane fuel in the turbocharged engine and the biodiesel fuel in the naturally aspirated engine could be a good alternative ratio to diesel fuel in diesel engines.
Dr Javad Zareei, Abbas Rohani,
Volume 11, Issue 2 (6-2021)

Diesel engines are the most trusted sources in the transportation industry. They are also widely used in the urban transportation system. Most pollutants are related to these engines. Therefore, it is important to increase the performance and reduce exhaust emissions of these engines. Alternative fuels are key to meeting upcoming targets.
An experimental and numerical study was performed to investigate the effect of diesel fuel and hydrogen addition to diesel fuel from 0 to 30% on performance and exhaust emissions. Also in this research for changing diesel fuel, an indirect injection engine converted to direct injection engine. The simulation study was conducted by Star cd codes and experimental investigation was carried out on a diesel engine (Perkins 1103A-33TG1), three- cylinders, and four-stroke with maximum engine power 72.3hp at 1800 rpm. The results from this study showed that the increase of hydrogen to diesel fuel improves the thermal efficiency, resulting in lower specific fuel consumption. Also, the results showed that adding hydrogen until 30%, the cylinder pressure increase by about 9% and occurred the delay of peak pressure about 8 degrees of a crank angle compared to diesel fuel. The other obtained results in emission with 30%H2+Diesel showed the soot emission reduced 11.3%, HC and CO reduced nearly 36%, but NOx increased by about 8.3% due to high combustion temperature.

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