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Anand Raj R.,Vellore Institute of Technology | Shrivastava S.,Vehicle Research and Development Establishment | Trikande M.W.,Vehicle Research and Development Establishment
2015 International Conference on Industrial Instrumentation and Control, ICIC 2015 | Year: 2015

Developing vehicles with semi-active suspension by replacing passive system has been a great interest in the field of automotive industry. Maintaining stability and performance in spite of uncertainties in working environment is a prior concern for designing successful control system. Skyhook control policy is adapted for giving good ride performance. This paper introduces an optimum method for controlling vibration of semi-active suspension system in a quarter car system. Fuzzy logic controller developed on the basis of skyhook algorithm is compared with on-off and continuous skyhook control in time domain. The results show that Fuzzy logic gives better vibration control and along with PID velocity control gives better ride comfort than its counterparts. © 2015 IEEE. Source


Ambekar A.,Indian Institute of Technology Bombay | Bhangale R.,Indian Institute of Technology Bombay | Dukale A.,Indian Institute of Technology Bombay | Gandhi R.,Indian Institute of Technology Bombay | And 3 more authors.
49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference | Year: 2013

Experimental investigation of spray combustion of the monopropellant nitromethane (NM) assisted by a hot surface is presented. Spray combustion of NM was studied in a constant volume combustion chamber fitted with glow plugs within the chamber pressure range of 1 to 5 bar. The sprays were produced by injecting approximately 0.1 ml of the propellant through a commercial gasoline injector. Ignition was achieved by using two glow plugs placed in a horizontally opposed manner at a distance of 70 mm from the nozzle tip within the chamber. The pressure rise within the chamber was used to elucidate the ignition and combustion processes. The ignition delays were found to be in the order of milliseconds, with high heat release rates accompanying the combustion phenomena. The maximum differential pressures reached during combustion were found to increase with chamber pressure up to 3 bar, and decrease thereafter. The rate of pressure rise achieved after combustion were also found to be dependent on the initial chamber pressures. FTIR spectrometry of the combustion products yielded further insight into the reactions. Source


Ambekar A.,Indian Institute of Technology Bombay | Mallick L.,Indian Institute of Technology Bombay | Gandhi R.,Indian Institute of Technology Bombay | Chowdhury A.,Indian Institute of Technology Bombay | And 2 more authors.
49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference | Year: 2013

An experimental investigation was conducted to characterize the strand combustion of pure isopropyl nitrate (IPN) blended with a known de-sensitizer dibutyl sebacate (DBS). The blend was prepared with 75% IPN mixed with 25% DBS by weight so as to mimic the composition of Otto fuel II. Quartz tubes of 3, 5, 7.5, and 9 mm in diameters were utilized to create the strands of various diameters. The experiments were conducted in a quiescent atmosphere of air and the ambient pressure was varied from 5 to 40 bar in steps of 5 bar. Ignition of the strands was achieved by using a heated 60 μm Nichrome wire dipped in the liquid. The dependence of the linear burning rate of IPN-DBS blends on ambient pressure as well as the strand diameter was elucidated. The temperatures in the flame zone were measured with K-type thermocouples of 250 urn diameter. The ambient pressure variation was investigated for a strand diameter of 5 μm while, the tube diameter variation was studied at 5 and 40 bar pressure. The linear burning rate of IPN-DBS blends in 5 mm diameter tube was found to rise with pressure. The gas phase temperature above the tip of the tube was measured using 250 μm K-type thermocouple. The burning rate of IPN-DBS blends was found to be lower than that of pure IPN as well as Otto fuel II. Source


Ambekar A.,Indian Institute of Technology Bombay | Mallick L.,Indian Institute of Technology Bombay | Gandhi R.,Indian Institute of Technology Bombay | Chowdhury A.,Indian Institute of Technology Bombay | And 2 more authors.
49th AIAA/ASME/SAE/ASEE Joint Propulsion Conference | Year: 2013

An experimental investigation was conducted to characterize the combustion of a pure monopropellant isopropyl nitrate (IPN). Quartz tubes of 3, 5, 7.5, and 9 mm inner diameter were utilized to create the strands of varying dimensions. The experiments were conducted in a quiescent atmosphere of air and the ambient pressure was varied from atmospheric pressure to 40 bar in steps of 5 bar. Ignition of the IPN strands was achieved by using a heated 60 μm Nichrome wire dipped in the liquid. The dependence of the linear burning rate of pure IPN on ambient pressure as well as the strand diameter was elucidated. The temperatures in the flame zone and liquid phase were measured by K-type thermocouples of 250 and 75 μm diameters respectively. The ambient pressure variation was investigated for strand diameter of 5 mm, while the tube diameter variation was studied at 1, 10, 20 and 40 bar pressure. The linear burning rate of pure IPN strands of 5 mm diameter was found to exhibit staged behavior where a steep rise in burning rate with pressure was observed after an initial decreasing trend. The linear burning rate was found to reduce with increasing tube diameter. The effect of IPN monopropellant flame was prominently observed only for pressures higher than 10 bar. Source


Ambekar A.,Indian Institute of Technology Bombay | Chowdhury A.,Indian Institute of Technology Bombay | Challa S.,Vehicle Research and Development Establishment | Radhakrishna D.,Vehicle Research and Development Establishment
Fuel | Year: 2014

An experimental investigation was conducted to characterize the monopropellant droplet combustion of pure and blended isopropyl nitrate (IPN), suspended on quartz fibers in a quiescent atmosphere. The blends were prepared by mixing varying percentages by weight of IPN with less viscous n-heptane, as well as highly viscous desensitizer dibutyl sebacate (DBS). Ignition was achieved by using a heated 60 μm Nichrome wire. The dependence of the burning rate constant of pure IPN on initial droplet diameter was investigated in the droplet size range of 0.79-1.97 mm. The blended IPN studies were carried out with initial droplet diameters of 2 and 1.5 mm for IPN-n-heptane and IPN-DBS blends respectively, to characterize the effect of gravimetric composition. The experiments revealed a strong dependence of IPN burning rate on droplet size. The IPN-DBS blends were characterized by severe micro-explosions, further atomizing the droplet, governed by the preferential evaporation of IPN over DBS. However, micro-explosions were conspicuously absent in case of IPN-n-heptane blends due to simultaneous gasification of both components. © 2013 Elsevier Ltd. All rights reserved. Source

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