Super-knock Suppression Using Split Injection in a Turbo-Charged GDI Engine

CATEGORY: SUPER-KNOCK
Super-knock Suppression Using Split Injection in a Turbo-Charged GDI Engine

Type	Journal Article
URL	Free Full Text Source:  http://search.proquest.com/openview/52aed15045869877360b0e2a5f254e14/1?pq-origsite=gscholar&cbl=2040549
Publication	MATEC Web of Conferences 40, 02011 (2016)
Date	2016
Abstract	With the energy crisis and environment pollution spreading all over the world, the technology that gasoline direct injection combine with turbo charger, as an important measure to reduce fuel consumption and improve emission of engine, is developed rapidly. An abnormal combustion phenomenon has been found in highly boosted SI engine, especially in turbo-charged gasoline direct injection (TGDI) engine, which is termed as super knock (Volkswagen calls it Super Knock [1], AVL names it Mega-Knock[2] and Pre-Ignition in IFP[3]),. Super knock is characterized as a pre-ignition usually followed by heavy detonation and sharp metal knock voice. Super knock occurs randomly and in an uncontrolled style, often just single occurs but it occasionally takes place two or more times in sequence and then disappears spontaneously, it is difficult to identify the root cause for this phenomenon and to develop solutions to eliminate it. The occurrence of super knock usually accompany with high frequency pressure wave, the maximum peak fire pressure in cylinder may reach up to 350Bar which bring fatal damage to engine, Although it is neither possible nor practical to eliminate super knock; thus, a suitable way for mitigating super is to weaken the conditions favor super knock . In order to suppress super knock, many studies have been done globally, such as spark plug gap, heat value, negative electrode has little effect on super knock is proved by Takuya Inoue from NGK[4]. Volkswagen Company and Vienna University [1] decreases super knock frequency by optimizing the structure of combustion chamber, eventually enhance brake mean effective pressure(BMEP). Christoph Dahnz[5] from KIT University proves that hot spot, which is widely believed as the cause for super knock, locating in combustion chamber randomly not the particular place, on the other hand, points out super knock maybe result in the interaction between fuel and oil droplets from wall by fuel inject splash. Southwest Research Institute proposes that mechanism of super knock maybe resulted from HC which exist in the crevice of combustion chamber. Akram Zahdeh[6] reduces super knock frequency substantially using split injection on a TGDI engine. In this paper, split injection strategy will be carried on a TGDI engine to restrain super knock, especially the end of second injection time (EOI) and the ratio of second injection (ROI) will be studied carefully.