A measuring method has been developed that can measure the liquid fuel (= wall-wet) quantity in an intake port and a cylinder under transient states. This method uses a specified single-cylinder research engine with a rapid valve train shutdown system for maintaining the wall-wet condition after it occurs and a transient state engine speed control that uses a low-inertia dynamo. This paper clarified the ratio of injected fuel at the 1st cycle from cold start (intake port wall-wet: 64%, cylinder wall-wet: 24%, burned fuel: 12%), and the increasing transition of these wet quantities cycle by cycle.As a result of the measurement described above, the following facts were discovered: (1) A wall-wet quantification method was developed that can measure intake port and in-cylinder wall-wet quantities with an accuracy of 2% under a transient state. This method uses a specified single-cylinder research engine with a rapid valve train shutdown system for maintaining the wet condition after it occurs and a transient state intake air mass flow control system. A low-inertia dynamo was used to control the single-cylinder research engine. (2) The fuel distribution of the 1st cycle injection was 64% intake port wall-wet, 12% burned fuel, 24% cylinder wall-wet, and less than 1% engine-out HC. (3) The wall-wet transitions during 6 cycles from engine start with CIV injection showed that intake port wall-wet increased and cylinder wall-wet became balanced from the 3rd cycle. After 6th cycle, 57% of the total injected fuel was intake port wall-wet and 16% of it was cylinder wall-wet. (4) In the case of OIV injection, intake port wall-wet was balanced and cylinder wall-wet increased during the 6 cycles. This means that inlet fuel flow to the cylinder with OIV injection was much larger than that with CIV injection. (5) Intake port wall-wet had a low impact on engine-out HC. It is believed that the increase in engine-out HC is influenced by the cylinder wall-wet quantity, cylinder wall-wet distribution, and mixture formation.
Quantitative analysis of intake port and cylinder wall-wet during cold start of port fuel injection engine
Quantitative Analyse der Ansaugkanal- und Zylinderwand-Feuchte beim Kaltstart eines PFI-Motors
Review of Automotive Engineering (JSAE) ; 30 , 4 ; 355-361
2009
7 Seiten, 16 Bilder, 2 Tabellen, 6 Quellen
Article (Journal)
English
Anwendung im Motorenbau , Ansaugkanal , Kaltstart , Kaltstartverhalten , äußere Gemischbildung , Zylinderwand , quantitative Analyse , Messverfahren , Forschungseinrichtung , transienter Zustand , Kraftstoff-Luft-Gemisch , Abgaszusammensetzung , indirekte Einspritzung , Otto-Motor , Abgasemission , Einflussgröße , Feuchte , aromatischer Kohlenwasserstoff
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