Effects of intake flow on the spray structure of a multi-hole injector in a DISI engine

Abstract

This is the accepted version of the paper.This version of the publication may differ from the final published version. ABSTRACT−The spray characteristics of a 6-hole injector were examined in a single cylinder optical direct injection spark ignition engine. The effects of injection timing, in-cylinder charge motion, fuel injection pressure, and coolant temperature were investigated using the 2-dimensional Mie scattering technique. It was confirmed that the incylinder charge motion played a major role in the fuel spray distribution during the induction stroke while injection timing had to be carefully considered at high injection pressures during the compression stroke to prevent spray impingement on the piston. Permanent

Effect of a split-injection strategy on the performance of stratified lean combustion for a gasoline direct-injection engine

“…In the case of a single injection, a lean mixture was formed owing to the increased penetration depth and widely spread fuel, and it is possible that misfire will occur. With a split injection with a injection duration of about 250-300 ms, it is thought that the reduced momentum of spray and the shortened penetration depth would lead to the formation of an ignitable mixture in the proximity of the spark plug with similar results to those of previous research studies [19,20]. Under relatively rich mixture conditions (l = 1.0 and 1.2), the COV IMEP value did not significantly change with each injection strategy; however, with a split injection, stable combustion was possible at a low injection pressure (such as 10 MPa) under lean operation conditions (l = 1.4 or higher).…”

Effect of the mixture preparation on the nanoparticle characteristics of gasoline direct-injection vehicles

“…However, because of incomplete combustion and poor mixture formation in the combustion chamber, GDI engines produce significant amounts of particulates during the cold-start phase and during transient operation. [3][4][5][6] Therefore, several parametric studies to reduce the particulate emissions from GDI engines have been conducted in conjunction with optimizing the engine control strategy, 7 mixture preparation with a high injection pressure, [8][9][10] modification of the combustion chamber 11 and implementation of particulate filters. 12,13 Epidemiological and medical findings indicate that adverse health effects are caused by aerosol particles in an ultrafine size range (diameter of less than 100 nm), which are associated with traffic and internal combustion engines as their main source.…”

Effects of intake flow and coolant temperature on the spatial fuel distribution in a direct-injection gasoline engine by PLIF technique

“…The engine used in this study was a single cylinder research engine designed for optical measurement [11,12]. It had 4-valve pentroof cylinder head with the injector and the sparkplug closely spaced using the sprayguided injection strategy for stratified fuel formation.…”

“…The number of injection exits of multi-hole injectors and their layout can be made to offer the flexibility in adapting the spray pattern layout to a particular combustion chamber design. The investigation on multi-hole injectors for gasoline engines has confirmed the improved spray stability in terms of spray cone angle compared to the swirl injectors [7][8][9][10][11][12][13][14]. In addition to the spray characteristics studies, experimental investigation has also been carried out inside injectors, demonstrating the complicity of in-nozzle flow caused by cavitations that in turn influence the stability of sprays exiting the injectors [15][16][17].…”

“…The key to success and also the challenge in DISI engines is to prepare fuel/air mixture towards the spark plug over the full range of engine operating conditions, as the fuel/air mixing process is influenced by many time dependant variables. In this study, a follow up of the previous study [11] by the same authors, the planar laser induced fluorescence technique is used to study the in-cylinder fuel concentration distribution generated by a high pressure multi-hole injector with the effect of the in-cylinder air charge motion, the coolant temperature of the engine cylinder head and the fuel injection pressure under the two main injection strategies, i.e. the homogenous charge mode and the stratified charge mode.…”