Experiment 3 Group 2 PDF

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UNIVERSITI TENAGA NASIONAL COLLEGE OF ENGINEERING DEPARTMENT OF MECHANICAL ENGINEERING

MEMB331 – MACHINE DESIGN & CAD LAB EXP. TITLE

: CAM AND TAPPET ANALYSIS (EXPERIMENT 3)

AUTHOR

: MUHAMMAD IFZAN BIN ABD RASHID

SECTION

: 01A

GROUP NUMBER : 2 INSTRUCTOR

: MR. ENG KIAN HIN

GROUP MEMBER : 1. MUHAMMAD IFZAN BIN ABD RASHID

(ME0103358)

2. MOHAMAD SHAFIQ BIN MOHAMAD SOBRIE

(ME0102690)

3. MORAD, WALEED KHALID DARWISH

(ME0101593)

Performed Date 10/03/2021

Due Date*

Submitted Date

17/03/2021

17/03/2021

*Late submission penalty: Late 1 day: 20%, Late 2 days: 40%, Late 3 days: 60%, More than 3 days: not accepted

ABSTRACT The Cam and Tappet Analysis experiment report was all about to record and determine tappet throw (lift and fall) for different cam profiles which included of convex cam and constant acceleration cam. The cam was used with a variety of followers to research various effects. The cam was used with dome and flat followers to obtain the necessary measurements. The experiment's findings were arranged into several tables.

Using the formulas given by the lab instructor, the velocity and acceleration of each cam were determined. For each cam, a graph of displacement vs. angle was drawn. Each cam's velocity and acceleration graph were also plotted. The experiment's details were clarified in greater detail in the discussion section. Our experiment showed that the tappet motion for the constant acceleration cam adopted the same profiles as the theoretical plotting, but the tappet motion for the tangent cam differed significantly from the theoretical plotting due to some error analysis.

From the experiment conducted, we found out that experimental value and theoretical value for Convex Cam and Constant Acceleration Cam exhibit the similar profiles.

DATA, OBSERVATION AND CALCULATION OF RESULTS

Type of Cam: Convex Crank Angle, θ 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360

Theoretical Tappet Position, (mm) 0 0.19 0.79 1.83 3.38 5.52 8.39 12.11 16.78 22.43 28.94 36.05 43.39 50.52 57 62.45 66.57 69.13 0 69.13 66.57 62.45 57 50.52 43.4 36.05 28.937 22.43 15 12.112 15 5.52 3.38 1.83 0.79 0.19 0

Experimental Tappet Position, (mm) 0 0.1 0.8 2 3.6 6 8.5 12.5 17.5 19.6 18.5 14.3 10.4 7.2 4.5 2.7 1.3 0.4 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0 0

Table 1 : Theoretical Position & Experimental Position of Tappet for different Crank Angle for Convex Cam

Sample of Calculations: Θ=60° sin 𝛼 = sin α =

35 sin(180 − 𝜃 ) 55

35 sin(180 − 60) 55 α = 33.44°

β=θ–α β = 60° - 33.44° = 26.58°

𝑂𝐸 = OE =

55 sin 𝛽 sin(180 − 𝜃)

55𝑠𝑖𝑛26.58/sin (180 − 60 ) OE = 28.39 mm

X = OE – 20mm = 28.39 -20 = 8.39mm

Type of Cam : Constant Acceleration Crank Angle, θ 0 10 20 30 40 50 60 70 80 90 100 110 120 130 140 150 160 170 180 190 200 210 220 230 240 250 260 270 280 290 300 310 320 330 340 350 360

Theoretical Tappet Position, (mm) 0 0.123 0.494 1.11 1.9753 3.086 4.44 6.05 7.9 10 12.098 13.95 15.556 16.913 18.024 18.88 19.5 19.876 20 19.876 19.5 18.88 18.024 16.913 15.556 13.95 12.098 10 7.9 6.05 4.44 3.086 1.9753 1.11 0.494 0.0123 0

Experimental Tappet Position, (mm) 0 0.1 0.5 1.15 2 3.2 4.6 6.2 8.3 10.4 12.4 14.2 15.7 17.05 18.2 19 19.7 20.15 20.3 20.3 19.99 19.4 18.6 17.6 16.45 14.9 13.15 11.2 9.1 7 5.35 3.85 2.5 1.6 0.8 0.25 0

Table 2 : Theoretical & Experimental Tappet Position for different Crank Angle for Constant

Acceleration Cam

Sample Calculation : 0° to 90°, Θ=60°

𝜃 2 ( ) 𝑥 = [ 15 ] 3.6 60 2 ( ) 𝑥 = [ 𝑖5 ] 3.6 X = 4.444mm

91° to 180°, θ=120° 180−𝜃 2 ) 19

20−(

𝑥=[

3.6

]

180 − 120 2 ) 15 𝑥 = [20 − ] 3.6 (

X= 15.556mm 181° to 270°, θ= 210° ( 𝑥 = 20 − [

𝑥 = 20 − [(

𝜃 − 180 15 )⁄ ] 3.6

210+80 2 15

) ∕ 3.6]

X = 18.889mm

271° to 360° Θ= 330°

( 𝑥=[ ( 𝜒=[

300 − 𝜃 2 15 ) ⁄ ] 3.6

360 − 330 )⁄ 15 3.6] 2

X= 1.111mm

Graph

Crank Angle vs Tappet Position 25

20

15

10

5

0 0

50

100

150

200

250

300

350

400

-5 Convex Cam Position

Constant Acceleration Cam

Graph 1: Tappet Position vs Crank Angle for Convex Cam & Constant Acceleration Cam

COMPARISON BETWEEN THEORETICAL & EXPERIMENTAL FOR CONVEX CAM VS CRANK ANGLE Theoretical Tappet Position, (mm)

Experimental Tappet Position, (mm)

80 70 60 50 40 30 20 10 0 0

50

100

150

200

250

300

350

400

Graph 2 : Tappet Position vs Crank Angle for Theoretical & Experimental for Convex Cam

Comparison between Theoretical & Experimental for Constant Acceleration Cam vs Crank Angle 25 20 15 10 5 0 0

50

100

150

Theoretical Tappet Position, (mm)

200

250

300

350

400

Experimental Tappet Position, (mm)

Graph 3: Tappet Position vs Crank Angle for Theoretical & Experimental For Constant Acceleration Cam

ANALYSIS AND DISCUSSIONS

By referring to the data collected, 3 graphs were plotted and each of the graph represented Crank Angle against Tappet Position, Comparison between Theoretical & Experimental for Convex Cam against Crank Angle and Comparison between Theoretical & Experimental for Constant Acceleration Cam against Crank Angle. Although each of the plotted graph was quite different with one another in terms of the technicality shape of the graph, but it does produce a significant to differ each functionality of the cam.

For the Tappet Position vs Crank Angle for Convex Cam & Constant Acceleration Cam graph, we can see the difference in shape of graph by referring on the Data Calculation & Observation section. The convex cam maximum experimental value is 19.6mm achievable at 90⁰ angle while maximum theoretical value is 69.13mm achievable at 170⁰ and 190⁰. The constant acceleration cam maximum experimental value is 20.3mm achievable at 180⁰ and 190⁰ angle while maximum theoretical value is 20mm achievable at 180⁰.

In the graph of comparison between theoretical & experimental for convex cam vs crank angle, there are lots of difference between the theoretical tappet position and experimental tappet position as the data being plotted throughout the graph, the experimental value denoted a linear motion when it reach around the 180⁰ angle which results in 0mm throughout the remaining 180⁰ angle position. The theoretical tappet position can be seen that it forming some sorts of dome but when it reaches out to the maximum point at 180⁰ the position close to 0mm. These sorts of differences caused by the calculation and experimental record different in conducting this experiment.

For the comparison between theoretical & experiment for constant acceleration cam vs crank angle graph, although each of the plotting was quite similar with one another in terms of

plotted data but it does exhibit a different value from each other. The difference can be seen clearly when the constant acceleration cam for theoretical and experimental differs out reaching at 250⁰ angle. But it reaches out to the same position back at 360⁰ angle at 0mm position.

Cam and tappet are widely use in an internal combustion engine, a tappet also called a valve lifter or a cam follower, generally this component functioning as to converts the rotation of the camshaft into the vertical motion which opens and closes the engine valves. As to reducing the wear from rotating the camshaft, the tappets are commonly circular and permissible to do rotations in a circular motion, this will help to avoid grooves developing at the same are as the tappets working.

Sample picture of overhead valves and their actuation mechanism. Camshaft is to far right and tappets are next to them.

Even though the recorded data between theoretical and experimental are not matches completely, they do bear close resemblance and difference value between them can be explained. As example the overhead valves picture above, the rotating parts and wear over the years may

cause the different in calculation, thus percentage error when comparing the actual recorded data and theoretical value.

CONCLUSION

We can conclude that the experiment's primary goals were accomplished. We discovered the tappet throw (lift and fall) of convex cam and acceleration cam. Nevertheless, to record and study the tappet motion (lift, velocity and acceleration) of convex cam and constant acceleration cam also been conducted successfully. As per requirement to plot the graph that shown the comparison between tappet motion of convex cam and constant acceleration cam have been convey effectively.

Despite the probability of relative errors between theoretical and measurement values, the overall effect of the profiles obtained is unchanged. This was confirmed by the error analysis, which revealed in this experiment data and observation section. Furthermore, we can deduce from the graphs that each type of cam and follower has its own displacement parameters, such as the constant acceleration cam having a higher displacement than the convex cam.

REFERENCES

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Rapid Design Through Virtual And Physical Prototyping, Cams. 2013. https://www.cs.cmu.edu/~rapidproto/mechanisms/chpt6.html

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Cam Mechanism (Mechanical Engineering). 2002 https://encyclopedia2.thefreedictionary.com/Cam+Mechanism

▪

Tappet. 2020. https://en.wikipedia.org/wiki/Tappet#:~:text=In%20an%20internal%20combustion%20engine% 2C%20a%20tappet%20(also%20called%20a,the%20intake%20or%20exhaust%20valve.

▪

Memb3021 machine design lab/memb331 machine design & cad laboratory unguided cam & tappet experiment. 2021. http://lms.uniten.edu.my/moodle/course/view.php?id=15846...