Sharif Digital Repository

Nowadays, according to environmental issues and fuel economy in internal combustion engines, the tendency to use of electrical and hybrid-electrical propulsions has become more than the past. On the other hand, still there are some problems like distance and charge time in electrical propulsions. Among them there are Hybrid-electric propulsions that have the benefits of two other propulsions. These propulsions are classified into three categories: series, parallel and series-parallel.Propulsion hybridization will change the cooling system. Internal combustion engine, electric motors, inverter and batteries operate at different temperature levels. So more than one cooling circuit with its own... 

For over a hundred years, vehicles have entered the human environment and influenced it. One of the most important effects that vehicles have on their surroundings and humans is their acoustic noise. The gearbox is one of the important components of the vehicle's transmission chain, in which the gears interact with each other and cause to create noise and vibration. These vibrations are transmitted through the bearings to the gearbox casing and then transferred to other parts of the vehicle via gearbox supports. Many researchers have studied the factors of NVH production in gearboxes and used methods such as gear profile modification and optimization of shaft and casing to reduce NVH. This... 

These days, the heat transfer phenomena is an important issue in internal combustion engines design because of direct effects on the performance, efficiency and emission of engine. One of the main parts is cylinder head which contacts with hot gases in combustion chamber and expose high heat flux. In this thesis, cylinder head of Tiba engine modeled by three dimensional and transient thermal analysis. In this modeling in order to consideration the effect of fluid flow, different domain of cylinder head (water jacket, intake/exhaust ports) has been simulated and appended to the model. Also combustion phenomena modeled separately, and then the heat transfer coefficient in the surface of...