Post Injection Process in Port Injection Systems P

Post Injection Process in Port Injection Systems P M V Subbarao Professor Mechanical Engineering Department Occurrence of an unwanted Process along with Vaporization….

Fuel Droplet Dynamics : Prediction of Arrival

Flow Simulation Compute the air velocity distribution. Use this data and distance between the injection nozzle and intake valve, the timing at which the fuel spray reaches the intake valve or manifold valve or any other surface before entering the cylinder is to be predicted.

Prediction of Droplet Paths • After the spray break up there is a drag force exerted on the droplets from the surrounding gases. • This drag tends to decrease the relative velocity between the drop and the gas flow. • From the Newton's Second Law, the equation is: Where dsmd is the droplet diameter, ug and usmd are the velocities of the gas flow and the liquid fuel droplet, respectively. And the drag coefficient CD is given as:

Spray Length in quiescent Gas Medium

Droplet Impingement Process

Variation of Volume Fluxes

Deposited Film Mass Fraction

Complex Multi-Physics leading to Random Results

YAMAHA MOTOR TECHNICAL REVIEW Shoichi Kato, Takanori Hayashida, Minoru Iida AFR 14. 5, Coolant Temp. 80℃ MEP 380 k. Pa,

Analysis Of Mixture And Wall Film Behavior The injection system configuration, injection timing and coolant temperature exert an influence on combustion stability and duration. Change of injection affects mixture formation in the intake port, wall film location and amount, size and amount of droplets, and finally mixture distribution in the combustion chamber.

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The System Reliability

Simplified Engineering fuel Evaporation model • In a simplified engineering model a representative diameter for the entire group is defined to compute evaporation rate. • Equivalent diameter of same number of uniformly sized droplets having same total surface area.

Details of Heat and Mass Transfer across Droplet

Droplet evaporation • The droplet evaporation rate is given by where d is the droplet diameter, DAB the gas diffusivity, Sh* the non-dimensional Sherwood number, and Bm the mass transfer number. The mass transfer number BM is equal to:

Port Fuel Injection System : Locations of Film Resevoirs

Partial-heating of the Intake Port

Surface temperature of the Port under different heating powers.

Effect of PH on In-cylinder HC Concentration

Increment of in-cylinder HC concentration