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Showing 3 results for Najafi

H. Biglarian, S. M. Keshavarz, M. Sh. Mazidi, F. Najafi,
Volume 4, Issue 4 (12-2014)

Many studies have been done on hybrid vehicles in the past few years. The full hybrid vehicles need a large number of batteries creating up to 300 (V) to meet the required voltage of electric motor. The size and weight of the batteries cause some problems. This research investigates the mild hybrid vehicle. This vehicle includes a small electric motor and a high power internal combustion engine. In most cases the car’s driving force is created by an internal combustion part. A small electric motor, which can operate as engine starter, generator and traction motor, is located between the engine and an automatically shifted multi-gear transmission (gearbox). The clutch is used to disconnect the gearbox from the engine when needed such as during gear shifting and low vehicle speed. The power rating of the electric motor may be in the range of about 15% of the IC engine power rating. The electric motor can be smoothly controlled to operate at any speed and torque, thus, isolation between the electric motor and transmission is not necessary. The present study evaluates the properties of the mild hybrid vehicle, its structure and performance and proposes an energy control model for its optimum operation.
Mr Mani Ghanbari, Dr Gholamhassan Najafi, Dr Barat Ghobadian,
Volume 10, Issue 4 (12-2020)

In this paper, the exhaust emissions of a diesel engine operating with different nanoparticles additives in diesel-biodiesel blended fuels were investigated. Firstly multi wall carbon nano tubes (CNT) with concentrations of 40, 80 and 120 ppm and nano silver particles of 40, 80 and 120 ppm with nano-structure were produced and then added as additives to the diesel-biodiesel blended fuels. A four-stroke six cylinders diesel engine was fuelled with the new fuels and operated at different engine speeds. The experimental results showed that CO2 emission increased by 17% with an increase in nanoparticles concentrations at diesel-biodiesel blended fuel. Also, CO emission with nanoparticles added to biodiesel-diesel fuel was 25.17% lower than neat diesel fuel. The results showed a decrease up to 28.56% in UHC emission using the silver nano-diesel-biodiesel blended fuel. NOx emission increased with adding nanoparticles to the blended fuels compared to the neat diesel fuel. The experimental results demonstrated that silver & CNT nanoparticles can effectively be used as additive in diesel-biodiesel blended fuel in order to enhance complete combustion of the air-fuel mixture and reduce the exhaust emissions. Consequently the nano biodiesel can be considered as an alternative and environment friendly fuel for CI engine. 

Abolfazl Mokhtari, Amin Najafi, Masoud Masih Tehran,
Volume 12, Issue 1 (3-2022)

Today, a large part of a vehicle's performance depends on its suspension. These expectations are addressed in this paper, including ride comfort, road-holding, and lateral stability. Due to the high statistics of lateral overturning, preventing lateral overturning and providing lateral stability of the vehicle is one of the most important goals of this paper. In this paper, a new type of suspension based on the Series Active Variable-Geometry is used by designing a simple Sliding Mode Controller (SMC) to improve vehicle dynamics. On the contrary previous studies in this field, asymmetric distribution of control command has been used to increase the usefulness of suspension in standard road roughness and during longitudinal and transverse maneuvers. In this paper, by simulating crosswind and double lane change maneuvers, several ideas have been used to command the suspension links, and a 25% to 30% improvement in vehicle dynamic performance parameters has been achieved.

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