Experimental and cfd analysis of the influence of fuel injection timing on the behavior of a gasohol-based gdi engine

ABSTRACT

This work examines the impact of FIT (Fuel Injection Timing) on engine’s performance of an automotive, Gasoline Direct Injection (GDI) engine using Gasohol (85% Gasoline + 15% Ethanol by mass) as fuel. The start of FIT was experimentally varied from −280 CAD (Crank Angle Degrees) to −330 CAD at 10 CAD intervals by using an open ECU. Experiments were performed at variable power outputs (such as 5, 8, 10, 13, 16, 18 and 21 kW) at a constant speed of 2500 rpm. CFD simulations were carried out for the above said conditions to understand engine’s behavior. Considering the conventional start of injection, advancing the FIT showed improvement the BTE (brake thermal efficiency) up to −320 CAD BTDC. The maximum BTE was observed as 31.8% at the engine power output of 21 kW (whereas it was 28.6% at −300°CAD). CFD results confirmed the improvement in the air-fuel mixing rate and swirl motion. With the use of advanced FITs, the emissions of carbon monoxide (CO) and hydrocarbons (HC) were decreased. The CFD emission results for CO and HC showed good agreement with the experimental findings. With the advanced FITs, NOx emissions showed an increase at all loads. The in cylinder pressure was observed to be higher with advanced FITs. Modeling results are very well supported with experimental pressures. It is concluded that advancing the fuel injection timing might improve the performance and lower HC and CO emissions of a Gasohol-based GDI engine. The optimized injection timing of −320 CAD could be recommended for the aforementioned engine’s greatest performance.

KEYWORDS:

• GDI engine
• fuel injection timing
• CFD modeling
• performance
• emissions

Acknowledgements

The authors thank the Department of Automobile Engineering, MIT Campus, Anna University, Chennai - 44’s CEAT (Centre for Excellence for Automobile Technology) for providing the full Engine Test Bed with all required equipment. Furthermore, the aforementioned Centre is much appreciated for providing the necessary workstation and sophisticated computer CFD software facility.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Notes on contributors

M. Senthil Kumar

M. Senthil Kumar is presently working as Professor in the Department of Automobile Engineering, Madras Institute of Technology, Anna University, Chennai, India. He holds Ph.D in Mechanical Engineering from the Indian Institute of Technology Madras, India. He has been teaching and guiding for Ph.D. students since 1996. His main research interests include Alternative fuels for CI engines, Dual fuel, RCCI and GDI engines with experimental and CFD.

M. Muniyappan

M. Muniyappan is presently working as a Teaching fellow and part time research scholar in the Department of Automobile Engineering, Madras Institute of Technology, Anna University. He did his master degree in Automobile Engineering from Anna University. He has been teaching and doing research since 2016. His main area of interests includes Alternative fuels for IC Engines, Computational fluid dynamics, GDI Engine Experiments.