AbstractThe study is aimed to control backfire, which is an abnormal combustionphenomenon, in a hydrogen fuelled spark ignition engine. It is importantto eliminate backfire as it can damage an engine’s intake system andhydrogen fuel supply system (possibility of explosion), and stall engine’soperation. Our research work indicates that backfire and NOx emission ina hydrogen fuelled spark ignition engine can be simultaneously controlledusing cooled EGR (exhaust gas recirculation), and water injection in theintake manifold of the engine. This study would be helpful to develop adedicated hydrogen fuelled spark ignition engine with more safety(engine damage and fuel explosion).

IntroductionHydrogen - Most promising alternative fuel for spark ignition engines

- Zero carbon based emissions (CO, CO2, HC)- High energy efficiency

Challenges - Backfire Solutions - Delayed H2 injection, - High NOx emission Cooled EGR, - Power drop water injection

Fig. 1 Illustration of backfire phenomenon

Materials and Methods

Fig. 2 Schematic diagram of experimental setup

References1. Vipin Dhyani, K.A. Subramanian (2019), Control of backfire and NOx

emission reduction in a hydrogen fueled multi-cylinder spark ignitionengine using cooled EGR and water injection strategies, InternationalJournal of Hydrogen Energy, Vol. 44 , Issue 12, pp. 6287-6298.

2. Vipin Dhyani, KA Subramanian (2018), Experimental investigation oneffects of knocking on backfire and its control in a hydrogen fueledspark ignition engine. International Journal of Hydrogen Energy, Vol.43, Issue 14, pp. 7169-7178.

3. KA Subramanian, BL Salvi (2016), A Numerical Simulation of Analysisof Backfiring Phenomena in a Hydrogen-Fueled Spark IgnitionEngine. ASME. J. Eng. Gas Turbines Power. 138(10):102811-102811-10.

AcknowledgementThis study is being carried out on the facility which has been createdusing the fund sponsored by Ministry of New & Renewable Energy(MNRE) and Kirloskar Oil Engines Limited (KOEL).

Conclusions➢ Backfire can be controlled by delaying the hydrogen injection,

cooled EGR and water injection in the intake manifold of the engine➢ Water injection is the most effective method to control backfire

along with NOx emission reduction without compromising theperformance of the engine.

➢ Backfire-free engine operation with ultra low (near zero) NOxemission was achieved with water injection.

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Industrial Significance➢ This research work provides a methodology for development of a

dedicated hydrogen fuelled spark ignition engine with better safety.➢ The safe or backfire free operation of the hydrogen fuelled spark

ignition engine can be achieved by optimizing the design andoperating parameters of the engine. This work would be areference source to industry for eliminating backfire.

Technology Readiness LevelThe backfire control technology has been developed and ready forimplementation.

Control of Backfire and NOx emission in a Hydrogen Fuelled Spark Ignition Engine

Vipin Dhyani and K. A. Subramanian*

Results

Industry Day Theme # 1: Clean Energy for Sustainable Economy and Environment

Control of backfire using cooled EGR, water injection and delayed hydrogen injection

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Visualization of backfire occurrence and its propagation using CFD

Fig. 4 Elimination of backfire using (a) cooled EGR and water injection (b) delaying hydrogen injection timing (IT)

Fig. 3 Backfire occurrence and its propagation in intake manifold of the engine

Fig. 5 Variation of (a) NOx emission (b) brake thermal efficiency with cooled EGR and water to hydrogen ratios (WHR)

(a) (b)

(a) (b)

Average turbulent flame

velocity: 230 m/s 𝑑𝑝

𝑑𝜃< 0.3 bar

Deflagration (sub-sonic)