Impact of liquid fuel injection timings on gaseous hydrogen supplemented -preheated straight vegetable oil (SVO) operated compression ignition engine

Abstract

ABSTRACTDirect usage of straight vegetable oil (SVO) in transportation division is still a big challenge because of its unfavorable qualities, such as: high density, high viscosity, and lower calorific value. The present investigation address this issue with synchronous work of three components (i) preheating of the SVO with waste heat recovery framework, (ii) advancing the injection timing of liquid SVO in pre-heated mode from its manufacturer recommended timing, and (iii) supplementing with small dosage of gaseous hydrogen (GH2). Experimental investigation was done on a Single cylinder, 4 S, Water cooled, naturally aspirated, In-direct Injection (IDI) diesel engine of 7.35 kW at 1000 rpm. The engine was operated under dual fuel mode with preheated SVO of 90°C (PHSVO-90) and supplemented GH2, by advancing the liquid fuel SVO injection timing from 20°, manufacturer recommended injection timing for diesel, to 26° bTDC. The impact of advancing the fuel injection timing on performance, emissions and combustion qualities of the engine was analyzed in detail. Thermal efficiency of the engine increased to 30.56% with advancing the injection timing from 20° to 22° bTDC which is even higher than conventional diesel. Engine out emission patterns were marginally vacillated with advanced injection timings. At 22° bTDC, Smoke and CO reduced from 45.2 HSU and 0.13% by volume to 34.7 HSU and 0.1% by volume. HC emissions remain unaffected whereas NOx was increased from 396 ppm to 440 ppm by advancing the injection timing from 20° to 22° bTDC. Cylinder pressure with 22° bTDC was 52.9 bar, which is higher than 20° bTDC and conventional diesel operation. Injection timing of 22° bTDC performed better results of higher efficiency and lower emissions when contrasted with different progressions and also comparable to conventional diesel operation. It is risen up out of the examination that advancing the injection timing to a specific cut off could be a suitable choice to improve the SVO-fueled engine performance and emission qualities.