J. Zareei, A. Rohani, Wan Mohd,
Volume 8, Issue 1 (3-2018)
Abstract
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.
Hamzeh Soltanali, Abbas Rohani, Mohammad Tabasizadeh, Mohammad Hossein Abbaspour- Fard, Aditya Parida,
Volume 8, Issue 3 (9-2018)
Abstract
Considering the present business competitive scenario, the automotive industry is under pressure to achieve higher productivity. A high level of performance and quality standard could be achieved through improving the Overall Equipment Effectiveness (OEE) of the equipment in an automotive industry. Thus, the aim of this study is to investigate the
performance measurement through OEE theory in an Iranian automotive industry.
Data and basic information collected from the Computerized Maintenance Management System (CMMS) of the production assembly lines. In this case study, two different assembly lines such Peugeot and Sports Utility Vehicle (SUV) were studied. The results indicated that the indices such availability rate, performance and
quality for Peugeot assembly line obtained an OEE value of 0.99, 0.70 and 0.38, respectively, and, these indices for SUV
assembly line obtained as 0.99, 0.39 and 0.53, respectively. Statistical analysis results of net operating time parameter for two assembly lines revealed that there is significant difference in the confidence level of 5% (P-value < 0.05). In addition,
the OEE index for Peugeot and SUV assembly lines gained 0.27 and 0.21 over a period of one year. Consequently, to improve the OEE in the automotive
assembly lines,
managing the time losses by systematic planning of manufacturing and the implementation of Total Productive Maintenance (TPM) are suggested.
Dr Javad Zareei, Abbas Rohani,
Volume 11, Issue 2 (6-2021)
Abstract
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.
