Cranking-Startup Intake Port and In-Cylinder Mixture Preparation Behavior in a CFR Gasoline Engine

Author(s):  
L. J. Hamilton ◽  
J. S. Cowart
Author(s):  
Jim S. Cowart ◽  
Leonard J. Hamilton

A Cooperative Fuels Research (CFR) gasoline engine has been modified to run on computer controlled Port Fuel Injection (PFI) and electronic ignition. Additionally a fast acting sampling valve (controlled by the engine control computer) has been placed in the engine’s intake system between the fuel injector and cylinder head in order to measure the fuel components that are vaporizing in the intake port immediately after the fuel injection event, and separately during the intake valve open period. This is accomplished by fast sampling a small portion of the intake port gases during a specified portion of the engine cycle which are then analyzed with a gas chromatograph. Experimental mixture preparation results as a function of inlet port temperature and pressure are presented. As the inlet port operates at higher temperatures and lower manifold pressures more of the injected fuels’ heavier components evolve into the vapor form immediately after fuel injection. The post-fuel injection fuel-air equivalence ratio in the intake port is characterized. The role of the fuel injection event is to produce from 1/4 to slightly over 1/2 of the combustible fuel-air mixture needed by the engine, as a function of port temperature. Fuel vapor sampling during the intake valve open period suggests that very little fuel is vaporizing from the intake port puddle below the fuel injector. In-cylinder fuel vapor sampling shows that significant fuel vapor generation must occur in the lower intake port and intake valve region.


1997 ◽  
Author(s):  
B. E. Holthaus ◽  
R. M. Wagner ◽  
J. A. Drallmeier

1999 ◽  
Author(s):  
Jiro Senda ◽  
Masanori Ohnishi ◽  
Tomohiro Takahashi ◽  
Hajime Fujimoto ◽  
Atsushi Utsunomiya ◽  
...  

Author(s):  
E. Movahednejad ◽  
F. Ommi ◽  
M. Hosseinalipour ◽  
O. Samimi

For spark ignition engines, the fuel-air mixture preparation process is known to have a significant influence on engine performance and exhaust emissions. In this paper, an experimental study is made to characterize the spray characteristics of an injector with multi-disc nozzle used in the engine. The distributions of the droplet size and velocity and volume flux were characterized by a PDA system. Also a model of a 4 cylinder multi-point fuel injection engine was prepared using a fluid dynamics code. By this code one-dimensional, unsteady, multiphase flow in the intake port has been modeled to study the mixture formation process in the intake port. Also, one-dimensional air flow and wall fuel film flow and a two-dimensional fuel droplet flow have been modeled, including the effects of in-cylinder mixture back flows into the port. The accuracy of model was verified using experimental results of the engine testing showing good agreement between the model and the real engine. As a result, predictions are obtained that provide a detailed picture of the air-fuel mixture properties along the intake port. A comparison was made on engine performance and exhaust emission in different fuel injection timing for 2600 rpm and different loads. According to the present investigation, optimum injection timing for different engine operating conditions was found.


2014 ◽  
Vol 1079-1080 ◽  
pp. 926-929
Author(s):  
Dan Han ◽  
Qian Wang ◽  
Bing Huan Li ◽  
Guo Jun Zhang ◽  
Shuo Wang

Intake port is an important part of the gasoline engine, its structure will influence the gas flow characteristics which directly affects the performance of the engine [1]. In this paper, three-dimensional CFD calculation and structural optimization were used to research the performance of gasoline engine. Firstly, the method of laser scanning and UG software were used to reverse modeling engine exhaust port and get the three-dimensional model. Secondly, after setting boundary conditions and turbulence models, the air flowing through the intake ports were simulated by FLUENT software respectively. Finally, based on numerical methods, the pressure field, velocity field were shown. The results of the simulation of flow field characteristics analysis show that the simulation and experimental results are in good agreement.


2012 ◽  
Vol 614-615 ◽  
pp. 376-380
Author(s):  
Chang Yuan Li ◽  
Dong Tang ◽  
Nan Li

Three-dimension transient numerical simulation of flow field in the transfer ports , exhaust port, intake port, crankcase and cylinder system of two-stroke gasoline engine was studied by using CFD software Fire, and the situations of airflow movement and exhaust gas distribution were presented dynamically in the scavenging process. The results show that flow field structure of the upper cylinder is mainly comprised of a pair of toroidal vortex and tumble vortex, while flow field structure of the lower cylinder is mainly comprised of four radial swirls and "short-circuiting" fuel losses. Along with the progress of scavenging process, the area of fresh charge and mixture increase while the exhaust gas area decreases accordingly. When the piston reaches to the BDC (bottom dead center), the exhaust gas area almost disappears.


Author(s):  
K Lee ◽  
C Lee ◽  
Y Joo

For the development of a high efficiency gasoline engine, the optimization of the intake port shape for a five-valve engine has been studied. Intake multivalve cylinder heads were manufactured by using a three-dimensional computer-assisted design program, and steady state flow experiments and flow visualization experiments have been performed with these cylinder heads. The five-valve engines, which have larger valve opening areas, have larger intake flowrates and higher tumble ratios than the four-valve engines. The effects of intake port design parameters of a five-valve engine on the intake flowrate and tumble were studied, and the design guidelines for the five-valve engines were established.


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