{ "metadata": { "name": "" }, "nbformat": 3, "nbformat_minor": 0, "worksheets": [ { "cells": [ { "cell_type": "heading", "level": 1, "metadata": {}, "source": [ "Chapter10:CI Engines-Fuel Injection System" ] }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.1 page no: 332" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "bsfc=0.3 #The brake specific fuel consumption in kg/kWh\n", "bp=250 #The brake power in kW\n", "N=1500 #Number of cycles per min in rpm\n", "CA=15 #Crank angle in degrees\n", "pi1=30 #The pressure of air in the cylinder at the beginning of the injection in bar\n", "pi2=60 #The pressure of air in the cylinder at the end of the injection in bar\n", "pf1=220 #The fuel injection pressure at the beginning in bar\n", "pf2=550 #The fuel injection pressure at the end in bar\n", "Cd=0.65 #The coefficient of discharge for the injector \n", "df=850 #The density of the fuel in kg/m**3\n", "p1=1.013 #The atmospheric pressure in bar\n", "n=4.0 #The number of orifices used in the nozzle\n", "x=6.0 #Number of cylinders\n", "\n", "#Calculations\n", "import math\n", "mf=bsfc*bp/60.0 \n", "F=(mf/(N/2.0))*(1/x) \n", "s=(CA/360.0)/(N/60.0) \n", "mf1=F/s \n", "p1=pf1-pi1 \n", "p2=pf2-pi2\n", "pa=(p1+p2)/2.0\n", "Af=(mf1/(Cd*(2*df*pa*10.0**5)**(1/2.0)))*10**6\n", "do=((Af/n)*(4/math.pi))**(1/2.0)\n", "\n", "#Output\n", "print\"The nozzle area required per injection = \" ,round(Af,3),\"mm**2\"\n", "print\"The diameter of the orifice = \",round(do,3), \"mm\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The nozzle area required per injection = 1.067 mm**2\n", "The diameter of the orifice = 0.583 mm\n" ] } ], "prompt_number": 1 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.2 page no: 333" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "bp=30 #The brake power of the engine in kW\n", "N=3000 #The engine speed in rpm \n", "bsfc=0.28 #The brake specific fuel consumption in kg/kWh \n", "Api=35 \n", "p2=160 #The pressure at which fuel is injected in bar\n", "CA=28 #The crank angle in degrees\n", "p1=35 #The pressure in the combustion chamber in bar\n", "Cv=0.92 #The coefficient of velocity \n", "\n", "#Calculations\n", "import math\n", "S=141.5/(131.5+Api) \n", "df=S*1000 \n", "D=(CA/360.0)/(N/60.0)\n", "F=(bsfc*bp)/((N/2.0)*60)\n", "mf=F/D\n", "Cf=Cv*((2*(p2-p1)*10**5)/df)**(1/2.0)\n", "Af=(mf/(df*Cf))*10**6\n", "d=(4*Af/math.pi)**(1/2.0) \n", "\n", "#Output\n", "print\"The velocity of injection of the fuel = \",round(Cf,1),\"m/s \"\n", "print\"The diameter of the fuel orifice = \",round(d,3),\" mm \"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The velocity of injection of the fuel = 157.8 m/s \n", "The diameter of the fuel orifice = 0.755 mm \n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.3 Page no 334" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "d=0.8*10**-3 #The diameter of an orifice in m\n", "A=1.65*10**-6 #The cross sectional area in m**2\n", "Cd=0.9 #The discharge coefficient of the orifice \n", "Cp=0.85 #The coefficient of the passage\n", "p1=170 #The injection pressure in bar\n", "p2=25 #The compression pressure of the discharge in bar\n", "df=850 #The density of the fuel in kg/m**3\n", "\n", "#Calculations\n", "Q=((145/(22.931*10.0**9))**(1/2.0))*10**6 \n", "p=170-(2.161*10**9*(Q/10.0**6)**2)\n", "Cf=Cd*((2*(p-p2)*10**5)/df)**(1/2.0)\n", "\n", "#Output\n", "print\"The discharge of fuel through the injector = \",round(Q,1),\"cm**2/s\" \n", "print\"The jet velocity through the orifice = \",round(Cf,1),\" m/s\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The discharge of fuel through the injector = 79.5 cm**2/s\n", "The jet velocity through the orifice = 158.2 m/s\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.4 page no: 336" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "s=20 #Spray penetration in cm\n", "t1=15.7 #The spray penetration of 20 cm in ms\n", "pi1=150 #The injection pressure in bar\n", "pi2=450.0 #The injection pressure to be used in bar\n", "p2=15 #The combustion chamber pressure in bar\n", "d1=0.34 #The diameter of the orifice in mm\n", "s1=20 #The penetration for an orifice in cm\n", "d2=0.17 #If the diameter of the orifice in cm\n", "t11=12 #The spray penetration in ms\n", "\n", "#Calculations\n", "t2=(t1*(pi1-p2)**(1/2.0))/(pi2-p2)**(1/2.0)\n", "s2=d2*(s1/d1)\n", "t21=t11*(d2/d1)\n", "\n", "#Output\n", "print\"(a) The time required for the spray to penetrate = \",round(t2,3),\"ms\"\n", "print\"(b) The spray penetration of the orifice = \",round(s2,3),\"cm\"\n", "print\"The time required for the spray to penetrate = \",round(t21,3),\"ms\"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a) The time required for the spray to penetrate = 8.746 ms\n", "(b) The spray penetration of the orifice = 10.0 cm\n", "The time required for the spray to penetrate = 6.0 ms\n" ] } ], "prompt_number": 7 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.5 page no: 336" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "v=6.5 #The volume of fuel in the barrel in cc\n", "d=0.3 #The dimeter of fuel pipe line in cm\n", "l=65 #The length of the fuel pipe line in cm \n", "vi=2.5 #The volume of fuel in the injection valve in cc\n", "K=78.5*10**-6 #The coefficient of compressibility of the oil per bar\n", "p1=1 #The atmospheric pressure in bar\n", "p2=180 #The pressure due to pump in bar\n", "v3=0.1 #The pump displacement necessary for the fuel in cc\n", "e=0.75 #The effective stroke of the plunger in cm\n", "\n", "#Calculations\n", "import math\n", "V1=v+((math.pi*d**2)/4.0)*l+vi\n", "V=K*V1*(p2-p1)\n", "T=(V)+v3\n", "L=T*(4/math.pi)*(1/(e**2))\n", "\n", "#Output\n", "print\"(a) The total displacement of the plunger = \",round(T,3),\"cc\" \n", "print\"(b) The effective stroke of the plunger = \",round(L,3),\"cm\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a) The total displacement of the plunger = 0.291 cc\n", "(b) The effective stroke of the plunger = 0.659 cm\n" ] } ], "prompt_number": 2 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.6 page no: 337" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "n=4.0 #Number of cylinders \n", "N=2500 #The engine speed in rpm \n", "P=90 #The power produced by the engine in kW\n", "bsfc=0.28 #The brake specific fuel consumption in kg/kWh\n", "v=3.5 #The volume of fuel in the barrel in cc\n", "vp=2.5 #Volume of fuel in the pipe line in cc\n", "vi=2.0 #The fuel inside the injector in cc\n", "p1=280.0 #The average injection pressure in bar\n", "p2=30.0 #The compression pressure of air during injection in bar\n", "df=850.0 #The density of the fuel in kg/m**3\n", "K=80*10**-6 #The coefficient of compressibility of fuel per bar\n", "pi=1.0 #The pressure with which fuel enter into the barrel in bar\n", "\n", "#Calculations\n", "import math\n", "F=(bsfc*P)/((N/2.0)*60)\n", "F1=F/n\n", "Vf=(F1/df)*10**6\n", "V1=v+vp+vi\n", "V=K*V1*(p1-math.pi)\n", "Vp=Vf+V\n", "W=((1/2.0)*(p1-math.pi)*10**5*V*10**-6)+((p1-p2)*10**5*Vf*10**-6)\n", "P1=(W*N)/(2*60*1000) #Power lost per cylinder in kW\n", "P2=P1*4 #Total power lost for pumping the fuel in kW\n", "\n", "#Output \n", "print\"The displacement volume of one plunger per cycle = \",round(Vp,3),\"cc\" \n", "print\"Total power lost for pumping the fuel = \",round(P2,3),\"kW\"" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "The displacement volume of one plunger per cycle = 0.276 cc\n", "Total power lost for pumping the fuel = 0.41 kW\n" ] } ], "prompt_number": 6 }, { "cell_type": "heading", "level": 2, "metadata": {}, "source": [ "Example 10.7 page no: 339" ] }, { "cell_type": "code", "collapsed": false, "input": [ "#given\n", "v1=0.3 #Velocity of the pump plunger in m/s\n", "l=0.575 #The length of the fuel pipe in m\n", "A=1/20.0 #The cross sectional area of pipe to the plunger cylinder\n", "a=1/40.0 #The area of nozzle hole to the pipe \n", "p1=27.6 #Initial pressure in the line in bar \n", "p2=27.6 #The compression pressure of the engine\n", "K=17830*10**5 #The bulk modulus of fuel in N/m**2\n", "df=860.0 #The density of the fuel in kg/m**3\n", "\n", "#Calculations\n", "Vs=(K/df)**(1/2.0)\n", "t=l/Vs\n", "Vp=(1/A)*v1\n", "p=((K/Vs)*Vp)/10.0**5\n", "pi=p+p1\n", "po=p1+p\n", "vc=Vp-(a*((2*(po-p2))/df)**(1/2.0))\n", "pr=26.8 #By trial , Pressure\n", "Vc=pr*(Vs/(K/10.0**5))\n", "po1=p1+p+pr\n", "vo=a*((2*(po1-p2)*10**5)/df)**(1/2.0)\n", "\n", "#Output\n", "print\"(a)The velocity of the pressure disturbance = \",round(Vs,0),\"m/s\"\n", "print\"(b) The time taken by the disturbance to travel through the pipe line = \",round(t,4),\" s\" \n", "print\"(c) The velocity at the pump end of the pipe line as the plunger moves = \",round(Vp,2),\" m/s\"\n", "print\"The pressure at the pump end of pipe line as the plunger moves = \",round(pi,2),\"bar\"\n", "print\"(d)The magnitude of the first reflected pressure = \",round(pr,2),\"bar\" \n", "print\"The magnitude of the first reflected velocity wave =\",round(Vc,2),\"m/s\" \n", "print\"(e)The pressure at the oriface end of the pipe line after the first reflection = \",round(po1,1),\"bar\"\n", "print\"The velocity at the oriface end of the pipe line after the first reflection = \",round(vo,2),\" m/s \"\n" ], "language": "python", "metadata": {}, "outputs": [ { "output_type": "stream", "stream": "stdout", "text": [ "(a)The velocity of the pressure disturbance = 1440.0 m/s\n", "(b) The time taken by the disturbance to travel through the pipe line = 0.0004 s\n", "(c) The velocity at the pump end of the pipe line as the plunger moves = 6.0 m/s\n", "The pressure at the pump end of pipe line as the plunger moves = 101.9 bar\n", "(d)The magnitude of the first reflected pressure = 26.8 bar\n", "The magnitude of the first reflected velocity wave = 2.16 m/s\n", "(e)The pressure at the oriface end of the pipe line after the first reflection = 128.7 bar\n", "The velocity at the oriface end of the pipe line after the first reflection = 3.83 m/s \n" ] } ], "prompt_number": 30 } ], "metadata": {} } ] }