Dr. Mahdi Shahbhakti

Assistant Professor, Mechanical Engineering-Engineering Mechanics

Mahdi Shahbhakti The US Department of Transportation’s National Highway Traffic Safety Administration (NHTSA) requires the vehicle corporate average fuel economy to be increased by 53% (from 15.1 to 23.2 km/l) for light duty vehicles from 2016 to 2025. In addition, the new US Environmental Protection Agency (EPA) emission standards (Tier III and LEV III) regulate that emissions of Nitrogen Oxides and Non- Methane Organic Gas (NOx+NMOG) reduces from current 99.2 mg/km to 18.6 mg/km in 2025 on fleet average for light duty vehicles. Thus, there is now a high demand for engine technologies with low fuel consumption and low NOx emissions. Dr. Shahbhakti's research is centered on developing advanced fuel-efficient combustion engines that promise a significant reduction in low NOx and particulate matters (PM) and greenhouse gas emissions. Low temperature combustion (LTC) engines are an emerging technology that combines characteristics of spark-ignited and diesel engines. Similar to spark-ignited engines the fuel-air charge is mostly premixed in LTC, and similar to diesel engines the mixture is ignited through compression ignition. These characteristics, combined with the use of lean mixtures allow LTC to achieve high efficiency and NOx emissions and PM.

A dual-fuel reactivity controlled compression ignition (RCCI) concept is beneficial to other modes of LTC engines such as Homogeneous Charge Compression Ignition (HCCI) or Premixed Charge Compression Ignition (PCCI) due to the existence of precise means for controlling the heat release rate and combustion phasing. In the RCCI strategy two fuels with different reactivity (auto-ignition characteristics) are blended inside the combustion chamber. Combustion phasing is controlled by the relative ratios of these two fuels and the combustion duration is controlled by spatial stratification between the two fuels. Our project is centered on developing an optimized RCCI engine combustion. Proper operation of RCCI engines requires an in-depth understanding of the interactions between fluid flows, turbulent mixing and chemical kinetics. Computational Fluid Dynamics (CFD) models need to be developed to provide the required understanding. The CFD models are used to investigate the performance and emission characteristics of RCCI engines. Furthermore the CFD models are used to consider the effects of different fuels with different reactivity for a given operating condition. Dr. Shahbhakti and his group's study primarily focuses on development and analysis of advanced combustion models of RCCI engines understanding of the key processes controlling RCCI engine combustion.

This research is done as part of Michigan Tech’s Advanced Power Systems Research Center (APSRC), and Dr. Shahbhakti and Dr. Jeffrey Naber are the principal investigators. The RCCI research study has been done in collaborative efforts with University of Wisconsin-Madison Engine Research Center (ERC), thus advanced methods of RCCI controls can be developed.

For more information, please visit Dr. Shahbhakti's website.

Recent publications

01 Grey-Box Modeling of HCCI Engines
M. Bidarvatan, V. Thakkar, M. Shahbakhti, B. Bahri, A. A. Aziz
Applied Thermal Engineering, vol. 70, p. 397 (2014)
02 Integrated HCCI Engine Control Based on a Performance Index
M. Bidarvatan, M. Shahbakhti
Journal of Engineering for Gas Turbines and Power, vol. 136, p. 101601 (2014)
03 Cycle-to-Cycle Modeling and Sliding Mode Control of Blended-Fuel HCCI Engine
M. Bidarvatan, M. Shahbakhti, S. A. Jazayeri, C. R. Koch
Control Engineering Practice, vol. 24, p. 79 (2014)
04 Thermodynamic Control-Oriented Modeling of Cycle-to-Cycle Exhaust Gas Temperature in an HCCI Engine
M. D. Firoozabadi, M. Shahbakhti, C. R. Koch, S. A. Jazayeri
Applied Energy, vol. 110, p. 236 (2013)
05 Understanding and Eetecting Misfire in an HCCI Engine Fuelled with Ethanol
B. Bahri, A. A. Aziz, M. Shahbakhti, M. F. M. Said
Applied Energy, vol. 108, p. 24 (2013)