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 indicate that backfire can be controlled byoptimizing operating parameters such as spark timing and injectiontiming, using cooled EGR (exhaust gas recirculation), supercharging andwater injection in the intake manifold of the engine. This study would behelpful to develop a dedicated hydrogen fuelled spark ignition enginewith more safety (engine damage and fuel explosion).

IntroductionHydrogen is identified as a most promising alternative fuel which cancompletely eliminate carbon based emissions (CO, CO2, HC) from theengine. However, there are some challenges associated with utilization ofhydrogen in a spark ignition engine such as backfire, high NOx emissionand power drop. Backfire is a pre-ignition phenomenon (abnormalcombustion) that takes place in the intake manifold or/and combustionchamber of the engine during suction stroke of port or manifold injectiontype hydrogen fuelled spark ignition engine. Due to backfire, the flamepropagates toward upstream in the intake manifold and thus can damageintake system, stall engine operation and sometime lead to explosion inhydrogen fuel supply system. Various strategies such as optimization ofdesign parameters (compression ratio, valves timing), optimization ofoperating parameters (spark timing, injection timing), cooled EGR, chargeboosting (supercharging, turbocharging) with EGR and water injection inintake manifold can be used for controlling backfire. A schematicdiagram of experimental setup to study backfire is shown in Fig.1.

Materials and Methods

Fig. 1 Schematic diagram of experimental setup

References1. V Dhyani, KA Subramanian (2018) Experimental investigation on

effects of knocking on backfire and its control in a hydrogen fueledspark ignition engine. International Journal of Hydrogen Energy,Volume 43, Issue 14, pp. 7169-7178.

2. 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.

3. BL Salvi, KA Subramanian (2016) Experimental investigation oneffects of compression ratio and exhaust gas recirculation onbackfire, performance and emission characteristics in a hydrogenfuelled spark ignition engine. International Journal of HydrogenEnergy, Volume 41, Issue 13, pp. 5842-5855.

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 in a Hydrogen Fuelled Spark Ignition Engine

Vipin Dhyani and K. A. Subramanian*

Results

Industry Day Theme # 4: Sustainable Habitat

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

Fig. 2 backfire occurrence and its propagation in intake manifold of the engine

Fig. 4 Variation of (a) NOx emission (b) brake thermal efficiency with cooled EGR and water to hydrogen ratios

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