1.0 RESULTSAND ANALYSIS
Fix the engine speed at 1500 rpm, then gradually increase the enginetorque output from 60 Nm to 140 Nm with a step of 20 Nm.
Fuel flow rate (gls)
Exhaust Temperature (⁰C)
Figure1: Graph of Fuel Flow Rate (g/s) against Torque (Nm)
Figure2: Graph of Power (kW) against Torque (Nm)
Figure3: Graph of BSFC (g/kW.hr) against Torque (Nm)
Figure4: Graph of Energy Efficiency against Torque
Fix the torque at 80 Nm, then increase engine speed from 1200 rpm to2000 rpm with a step of 200 rpm.
Fuel flow rate (gls)
Exhaust Temperature (⁰C)
Figure5: Graph of Fuel Flow Rate (g/s) against Speed (rpm)
Figure6: Graph of Power (kW) against Speed (rpm)
Figure7: Graph of BSFC (g/kW.hr) against Speed (rpm)
Figure8: Graph of Energy Efficiency against Speed (rpm)
TestProcedure 1: Duringthis test procedure, the engine was fixed at a speed of 1500 rpm, andengine torque was gradually increased from 60 Nm to 140 Nm with astep of 20 Nm. The following was observed about the data obtained
Torque (Nm) verses Fuel flow rate (g/s)
Torque is part of the basic specificationof an engine: it is defined as the tendency of a force to rotate anobject about an axis. Fuel flow rate is defined as the quantity offuel an engine uses or burns each hour to generate torque. The graphof fuel flow rate against torque (Figure 9)is a smooth curve showing fuel flow rate increasing steadily withincrease in engine torque. This means when an engine generates moretorque its fuel consumption is high.
Torque (Nm) verses Power (kW)
Engine power is defined as the speed orrate at which work is performed. In figure10 where we have the graphof power against torque we can see that power increases steadily withincrease in engine torque.
Torque (Nm) verses Brake Specific Fuel Consumption (BSFC)
BrakeSpecific Fuel Consumption (BSFC) is a measure of fuel efficiency of arunning engine that burns fuel to produce shaft or rotational power.The graph of BSFC against torque (figure 3) is a smooth curve. Fromthe graph BSFC decreases steadily with increase in torque until wherethe torque reaches 80 Nm, it then starts increasing steadily withincrease in torque. At a torque of 100 Nm, BSFC starts to decreaseagain steadily with an increase in torque.
Torque (Nm) verses Energy Efficiency
Energy efficiency refers to therelationship between the total energy contained in the fuel, and theamount of energy used by the engine to generate power. The graph ofenergy efficiency against torque is a smooth curve showing thatenergy efficiency increases with increase in torque until 125 Nmwhere it starts to drop steadily.
TestProcedure 2: During thistest procedure engine torque was fixed at 80 Nm, then engine speedincreased from 1200 rpm to 2000 rpm with a step of 200 rpm. Thefollowing was observed about the data obtained
Speed (RPM) verses Fuel Flow Rate g/s
The graph of fuel flow rate against speed(figure 4) is a smooth curve indicating fuel flow rate increasingsteadily with an increase in engine torque. This means for an engineto achieve high speed it burns more fuel to produce torque.
Speed (RPM) verses Power (kW)
The graph (figure 5) obtained by plottingpower against speed is a straight line that shows power increasingsteadily with engine speed increase. This means a fast engine hasmore power or produces more power.
Speed (RPM) verses BSFC
The graph of Brake Specific FuelConsumption (BSFC) against engine speed (figure 6) is a smooth curvewhich decreases steadily with an increase on speed until it reaches1600 rpm then it starts to rise steadily as the speed increases. Atabout 1850 rpm it starts decreasing steadily.
Speed (RPM) verses Energy Efficiency
The graph of energy efficiency againstspeed (figure 7) is a smooth curve indicating energy efficiencyincreasing steadily with an increase in speed until the engine speedreaches 1600 rpm. From 1600 rpm energy efficiency starts to decreasewith an increase in speed. From 1800 rpm energy efficiency starts torise again.
From the results and data analysiswe can conclude that an increase in engine torque affects fuel flowrate, power and energy efficiency positively. That is to mean enginetorque is directly proportional to engine power, fuel flow rate andenergy efficiency. While for Brake SpecificFuel Consumption (BSFC) the first 20 Nm engine torque increase it isinversely proportion then rises steadily. This drop might due to lowengine temperature at the start and low fuel flow rate into theengine.
We canalso conclude that engine speed is directly proportion to basicengine specifications like power, fuel flow rate, and energyefficiency. For Energy efficiency there is a maximum speed increaselimit that the energy efficiency increases, past this limit it startsto drop. However, when it comes to the effect of engine speed onBrake Specific Fuel Consumption (BSFC) the results are different thatis, BSFC decreases with increase in speed until a certain speed isattained then it starts to rise.
DanielMiessler,( 2015): The relationship Between Horsepower, Torque andAcceleration. Available from
EPI Inc.(2015): Power and Torque: Understanding the relationship betweenengine power and engine torque. Available from