1 files changed, 21 insertions, 0 deletions
diff --git a/2063/CH7/EX7.21/7_21.sce b/2063/CH7/EX7.21/7_21.sce
new file mode 100755
index 000000000..6b7a22118
--- /dev/null
+++ b/2063/CH7/EX7.21/7_21.sce
@@ -0,0 +1,21 @@
+clc
+clear
+//Input data
+N=1200;//Operating speed of a four cylinder engine in rpm
+BHP=25.3;//The brake horse power when all 4 cylinders are operating in kW
+T=10.5;//The average torque when one cylinder was cut out in mkgf
+CV=10000;//Calorific value of the fuel used in kcal/kg
+f=0.25;//The amount of petrol used in engine per BHP hour
+J=427;//
+
+//Calculations
+BHP1=(2*3.14*N*T)/4500;//BHP for 3 cylinders when 1 cylinder is cut out in kW
+IHP=BHP-BHP1;//IHP of one cylinder in kW
+IHPt=IHP*4;//Total IHP of the engine with 4 cylinders
+Wf=(f*BHP)/60;//Fuel used per minute in kg
+ni=((IHPt*4500)/(Wf*CV*J))*100;//Indicated thermal efficiency in percent
+nm=(BHP/IHPt)*100;//Mechanical efficiency in percent
+nb=(IHPt*nm)/100;//Brake thermal efficiency in percent
+
+//Output
+printf('The indicated thermal efficiency is %3.1f percent',ni)