FINAL INDEPENDENT PROJECT
AIM- 4 PISTON ASSEMBLY MODEL AND MOTION ANALYSIS.
INTRODUCTION- In our 4 piston four stroke assembly we have a crankshaft and the piston assembly which consist of piston, connecting rod, gudgeon pin. We use alloy steel to make the parts for assembly. This 4-piston assembly is same as single piston but there is different is the four piston are present in this assembly. The working is similar to single cylinder engine as in this four-cylinder engine. When two pistons going down the other pistons going down at the same time. That is the different between 4 cylinder and single cylinder engine.
Let’s see some components of this assembly.
Piston
Connecting rod
Gudgeon pin
Crankshaft
THEORY
Calculation
As we know
1 stroke of piston = 180 degree
So, 4 stroke of piston = 720 degree
Means that engine completes 4 strokes of piston in two revolution of crankshaft.
We can calculate linear displacement by following formula
V = (Pi/4 *) sb^2n
So here,
V = engine displacement
S = stroke
B = bore diameter
N = no of cylinder in respected engine
So, by above formula we can calculate our linear displacement
For angular velocity
V= W/R
Here
V = angular velocity
W = omega = 2*3.14*N/60
R = radius
STEPS-:
Now let’s see how we make our model of 4 piston assembly.
There are following steps
1.Open soildworks and then as new part
2.Click on front plane and draw this sketch as seen in image.
3.Then revolve this sketch
4.Then we draw a sketch on front plane as seen in img.
5.Then we cut extrude through all then it look like this
6.Now draw this sketch on front plane.
7.Then extrude this sketch as select offset 12mm and direction select as upto surface
8.Then select outer surface of piston and then click on reverse direction.
9.Then mirror this feature to other side.
Then save this part as piston.
Gudgeon pin
1.Click new window and then new part.
2.Then click on front plane and make sketch is shown below.
3.And then extrude as blind mid plane upto 45mm and apply thin feature 2.50mm reverse direction.
4.Then chamfer the edge upto 0.5mm.
Then save this part as piston pin.
Connecting rod
1.Open new window as new part.
2.Then click on front plane and make this sketch as shown below.
3.Then extrude upper circle and below circle area upto 20mm and direction as mid plane.
4.Then extrude other left areas as mid plane plane and distance upto 12mm.
5.Now click on right plane and make this sketch as shown.
6.Then extrude cut this sketch as offset as 6mm and direction as through all.
7.Then mirror this feature to other side.
Then save this part as connecting rod.
Crankshaft
1.Open new window as a part.
2.Then click on right plane and make this sketch as shown below.
3.Then extrude inner sketch as 25mm as blind condition.
4.Then extrude outer circle as 25 mm blind.
5.Then make sketch on as highlighted part area.
6.Then made this sketch as seen below.
7.Then extrude to 15mm as blind condition.
8.And then make sketch on this face.
9.Make this sketch on that highlighted area.
10.Then extrude the sketch to 15mm.
11.Then we mirror that particular features that are necessary to mirror that are highlighted on img make sure the geometry option is check mark.
12.Then it looks like this.
13.Then we make again sketch on that particular highlighted area.
14.Make this sketch.
15.Then extrude this sketch upto 5mm as blind condition.
16.Then we make again sketch on highlighted part area.
17.Now we first we have to select sketch 2 and then convert entities it and then rotate by using rotate entities 180 deg.
18.Then extrude it upto 15 mm
19.Then we again made sketch on highlighted part area that is seen below.
20.Draw this sketch as seen below.
21.Then we extrude this sketch upto 30 mm as blind condition.
22.Final crankshaft look like this.
Then save this part as crankshaft.
ASSEMBLY
1.Open as new window as assembly.
2.Then insert all components
3.And apply various constrain to make assembly possible.
REPORT ON MOTION ANALYSIS
To analysis this 4-piston assembly we set some parameters before we proceed to motion analysis,
Material for all components = alloy steel
We take engine rpm as idle = 1700 rpm
We take for motion analysis fps = 7200
After motion analysis we get some plots here so let’s see
Linear displacement of piston 1 plot
Linear displacement of piston 2 plot
Linear displacement of piston 3 plot
Linear displacement of piston 4 plot
Angular velocity of crankshaft plot
EXPALNATION
By motion analysis
- Linear displacement of piston 1 shows that
When RPM = 1200 and time = 0.75
Maximum displacement is to be 260mm.
- Linear displacement of piston 2 shows that
When RPM = 1200 and time = 0.75
Maximum displacement is to be 203mm.
- Linear displacement of piston 3 shows that
When RPM = 1200 and time = 0.75
Maximum displacement is to be 154mm
- Linear displacement of piston 4 shows that
When RPM = 1200 and time = 0.75
Maximum displacement is to be 121mm
This variation in linear displacement happen in plot because due to time related with piston arrangement of vertical distance is not proper at that time when we start our motion analysis. By the way the maximum distance that each piston cover to be 260mm.
And the maximum angular velocity we obtained at crankshaft by out plot.
10200 at time 0.75.
TO SEE VIDEO OF MOTION ANALYSIS CLICK THAT LINK DOWN BELOW