Internal Flow System Analysis for Engine Fuel System
For the typical gasoline port fuel injection system shown below:
Assume two injectors (only A and C are running) are running simultaneously at a steady flow rate of 50lt/hour from each injector, and the pressure regulator is returning 100 lt/hour to the fuel tank.
a) Calculate the nozzle diameter to deliver the fuel flow velocity at 25 m/s.
b) Perform hand calculations to estimate the pressure drop in each element of the system. Present the results of calculations for the major and minor pressure losses in a table (listing all elements with its diameter, length, velocity, KL and etc.) and determine the total pressure loss for the system.
c) Calculate the fuel pump pressure for the system operation( Pout) .
d) Calculate the mechanical power to drive the fuel pump.
Make all the necessary assumptions and discuss the effect of your assumptions on the final results.
The following data given on the next page has been collected for the fuel injection system. The students will choose the dimensions of the pipe connecting the fuel tank to the fuel filter and the position of the pressure regulator on the return pipe.
Common rail pipe (4)
Length : 360 mm
Internal diameter : 12 mm
Injectors are located at equal distance: 90 mm
The hose connecting the filter to the common rail pipe
Length : 1200 mm
Internal diameter : 5 mm Fuel filter
Pressure drop : 0.35 psi at 200 litres/hour flow rate
Injector connecting pipe(all same at A, B , C, D)
Length : 70 mm
Diameter : 5 mm
Injector
Discharge coefficient :1
Return pipe (from pressure regulator to the tank)
Length : 1300 mm
Diameter : 4 mm