Visualization of liquid fuel behavior in a spark ignition engine during starting and warm-up

1997 ◽  
Vol 11 (5) ◽  
pp. 582-593 ◽  
Author(s):  
Younggy Shin
2005 ◽  
Vol 128 (2) ◽  
pp. 397-402 ◽  
Author(s):  
Jim S. Cowart

During port-fuel–injected (PFI) spark-ignition (SI) engine startup and warm-up fuel accounting continues to be a challenge. Excess fuel must be injected for a near stoichiometric combustion charge. The “extra” fuel that does not contribute to the combustion process may stay in the intake port or as liquid films on the combustion chamber walls. Some of this combustion chamber wall liquid fuel is transported to the engine’s oil sump and some of this liquid fuel escapes combustion and evolves during the expansion and exhaust strokes. Experiments were performed to investigate and quantify this emerging in-cylinder fuel vapor post-combustion cycle by cycle during engine startup. It is believed that this fuel vapor is evaporating from cylinder surfaces and emerging from cylinder crevices. A fast in-cylinder diagnostic, the fast flame ionization detector, was used to measure this behavior. Substantial post-combustion fuel vapor was measured during engine startup. The amount of post-combustion fuel vapor that develops relative to the in-cylinder precombustion fuel charge is on the order of one for cold starting (0 °C) and decreases to ∼13 for hot starting engine cycles. Fuel accounting suggests that the intake port puddle forms quickly, over the first few engine cranking cycles. Analysis suggests that sufficient charge temperature and crevice oxygen exists to at least partially oxidize the majority of this post-combustion fuel vapor such that engine out hydrocarbons are not excessive.


1995 ◽  
Author(s):  
Kimitaka Saito ◽  
Kiyonori Sekiguchi ◽  
Nobuo Imatake ◽  
Keiso Takeda ◽  
Takehisa Yaegashi

2003 ◽  
Author(s):  
K. Majmudar ◽  
K. Aung

The use of alternative fuels such as methanol and ethanol in spark-ignition (SI) engines is beneficial to the environment as it reduces emissions of pollutants such as NOx from these engines with slight penalty on the performance. This paper investigated the use of liquid fuel blends such as ethanol/gasoline blend in an SI engine by numerical simulations. The numerical simulations were based on the models of finite heat release, cylinder heat transfer, pumping losses, and friction losses. Simulations were carried out to evaluate the effects of compression ratio, equivalence ratio, ignition timing, and engine speed on the performance of the SI engine. The results of the simulations were compared with experimental data from the literature to validate the simulations. Good agreements between the computed and experimental results were obtained. The results showed that the current model could satisfactorily predict the performance of an SI engine fueled by liquid fuel blends.


Author(s):  
Maria Carmela De Gennaro ◽  
Giovanni Fiengo ◽  
Luigi Glielmo ◽  
Stefania Santini

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