A. Amini, M. Mirzaei, R. Khoshbakhti Saray,
Volume 3, Issue 4 (12-2013)
Abstract
In spark ignition (SI) engines, the accurate control of air fuel ratio (AFR) in the stoichiometric value is
required to reduce emission and fuel consumption. The wide operating range, the inherent nonlinearities
and the modeling uncertainties of the engine system are the main difficulties arising in the design of AFR
controller. In this paper, an optimization-based nonlinear control law is analytically developed for the
injected fuel mass flow using the prediction of air fuel ratio response from a mean value engine model. The
controller accuracy is more increased without chattering by appending the integral feedback technique to
the design method. The simulation studies are carried out by applying severe changes in the throttle body
angle to evaluate the performance of the proposed controller with and without integral feedback. The
results show that the proposed controller is more effective than the conventional sliding mode controller in
regulating the AFR without chattering.
Dr Ali Qasemian, Mr Sina Jenabihaghparast, Mr Pouria Azarikhah,
Volume 12, Issue 3 (9-2022)
Abstract
In the current study, the hydrogen-addition influence on the performance of an SI engine using a gasoline-ethanol blend is investigated numerically. The simulation and validation of the model are carried out in order to evaluate the engine performance using conventional gasoline (G100) and the blend of gasoline and ethanol (G75E25). Furthermore, the hydrogen is added to the gasoline–ethanol blend (G50E25H25) to improve the engine thermal efficiency and reduce the amount of brake specific fuel consumption (BSFC) which leads to the reduction in greenhouse gas (GHG) emissions. The brake specific carbon dioxide (BSCO2) is also studied in this paper. Results show that the addition of hydrogen increases the brake power and thermal efficiency, moderates the BSFC, and decreases the maximum temperature of combustion chamber which reduces the production of greenhouse gases as well as BSCO2. In comparison with pure gasoline, by using G50E25H25, the maximum temperature of in-cylinder gas decreased by 12.55%, 10.82%, and 13.43% at 2000, 4000, and 6000 rpm, respectively. It is also evaluated that the lowest amount of BSCO2 is related to G50E25H25 in most of the engine speeds. The bio-fuel of G75E25 and pure gasoline are placed in next positions, respectively.
