A novel twin injector strategy for direct cylinder barrel injection of LPG in a 2S-SI engine. (15th December 2015)

• Record Type: Journal Article
• Authors: Pradeep, V.; Ramesh, A.
• Is Part Of: Fuel. Volume 162(2015)
• Page Start: 128
• Page End: 137
• Publication Date: 2015-12-15
• Subjects: Two stroke engines -- LPG -- HC emissions -- Short-circuiting; LPG liquefied petroleum gas -- MI manifold injection -- 2S-SI two-stroke spark-ignition engine -- MBT minimum advance for best torque -- DI direct injection -- SOI start of injection -- LPG_TDI direct in-cylinder LPG injection through cylinder barrel with two injectors -- LPG_SDI direct in-cylinder LPG injection through cylinder barrel with single injector -- TP transfer port opening -- EOI end of injection -- EPO exhaust port opening -- BPO boost port opening -- TPO transfer port opening -- BPC boost port closing -- TPC transfer port closing -- EPC exhaust port closing -- HC hydrocarbon -- NO nitric oxide -- CO carbon monoxide -- °CA degree crank angle -- BTE brake thermal efficiency -- Φ equivalence ratio; Fuel -- Periodicals; Coal -- Periodicals; Coal; Fuel; Periodicals; 662.6
• DOI: 10.1016/j.fuel.2015.08.070
• Languages: English
• ISSNs: 0016-2361

Abstract

Highlights: Energy saving, low pressure, direct gaseous LPG injection in engine. Significant reduction in HC emissions at all operating conditions. More suitable for improved injector durability. Abstract: A novel strategy of using twin injectors mounted on the cylinder barrel of a two-stroke spark ignition (2S-SI) engine for direct injection of Liquefied petroleum gas (LPG) is developed and compared with manifold injection. Gaseous LPG at a low pressure of about 4–4.5 bar was used and the injectors were located opposite each other and above the transfer ports. Experiments were conducted at the best injection and spark timings at 3000 rpm. Results at 25% and 100% throttle positions over different overall equivalence ratios are presented. The twin direct injection system led to significant reductions in hydrocarbon (HC) emissions of about 80% at both the throttle positions as compared to the manifold injection method due to reduction in short-circuiting losses. The best brake thermal efficiency was also improved from 19.7% to 25.2% at full throttle. Oxides of Nitrogen (NO) emissions were lower and carbon monoxide (CO) levels were higher due to charge non homogeneity. Experiments were also done with a single injector mounted on the cylinder barrel. The twin direct injection system resulted in significantly lower HC emissions and allowed operation under wider range of equivalence ratios with later injection timings as compared to the single injector strategy indicating its superior mixture preparation characteristics.