Week 2 : Basic Calibration of Single cylinder SI-Engine

Q.Run the case at 1800 rpm and list down important parameters (20 Marks)

• air flow rate
• BMEP
• BSFC
• In-cylinder pressure

Ans:- The case setup is single cylinder SI Engine as shown Below. This case is load from Tutorial -Engine Performance-1Cyl SI Engine.

The intial Inlet condition of air is as shown below

Pressure = 1 bar

Temperature =300K

Engine Speed =1800 RPM

Case Setup is given below

Then Click on Run botton to simulate case setup as shown below.Time flag control is periodic and Maximum simulation time is 10 sec with option of automatic shut off when steady state reach.

After simulation of case setup GT-Post open to show results

Results

P-Thita graph

P-Thita graph show sudden rise of pressure inside combustion chamber while combustion of fuel. The Maximum Pressure Generated in combustion bar is 48bar.

Temperature Graph

Temperature graph represent sudden increase in temperature in combustion chamber. The Maximum rise in temperature is 2510 K while combustion of fuel in combustion chamber

Engine Performance Parameter

Engine Geometric Parameters and valve Timming are shown below.The case setup is run with these initial parameters at 1800RPM

Output Results

Brake Power =7.1Kw

Brake Torque = 37.7Nm

AIR Flow Rate = 24.6 Kg/h

BSFC = 239.2 g/Kw-h

In cylinder Pressure = 48bar

BMEP= IMEP-FMEP

= 10.61-1.13

= 9.48 Bar

Increase Power 10%

The rated power can be increased by changning Engine volume (Bore,Stroke),RPM,Intake Air temperature and fuel injection quantity.

Changning Engine volume

The change in either Bore,Stroke and both will change Engine volume. It will change compression ratio. As compression ratio is given below

CR = V(Stroke) + V (Clearance) / V(clearance)

Case-1 BY Changing Bore Values

Bore values are change to 86mm, 89mm and 92 mm and stroke remain constant at 86mm. With increase of Compression Ratio the Power of Engine is also increased

The Power is increased to 7.7 Kw as given below with increased of Bore to 89mm

Case-2 BY Changing Stroke Values

The stroke is changed to 86mm,90mm and 94 mm while bore remain same at 86mm. It will also change compression ratio and power will also increased.

The power will increased to 10% with change of stroke to 86mm as shown below

Case-3 BY Changing both Bore and Stroke Values

The compression ratio will also changed by changing both Bore and stroke value. It will also increased Power of Engine. In this case bore and Stroke value set to 88mm as given below

There is 10 percentage of power increased as value is 7.7 kw given below

RPM Change

Change in RPM will also increase Power of Engine.In below case Engine is Run at 1800,2000,2200,2400 rpm Respectively.

AT 2000 RPM Engine Power is increased to 7.6 Kw which is 10% of initial Engine Power.

Air Intake Temperature

Decrease in Air Intake Temperature will also increase Power. As Density of Air is increased by Decrease in Temperature so more air will be entered in cylinder. In below case Engine intake temperatue is at 300K and 295 K.

AT 295K air intake Temperature Power of Engine is increased

By Changing fuel injection rate

Change in Fuel injection rate will change Air-Fuel Ratio.It will also increased Engine Power. It will effect Engine Emmission norms as it will increase Smoke value.

So above mension methods will increase Engine Performance parameters.