WEEK 12 Dynamics of Machinerykisi.deu.edu.tr/hasan.ozturk/makina...
Transcript of WEEK 12 Dynamics of Machinerykisi.deu.edu.tr/hasan.ozturk/makina...
WEEK 12Dynamics of Machinery
• References Theory of Machines and Mechanisms, J.J.Uicker,
G.R.Pennock ve J.E. Shigley, 2003
Prof.Dr.Hasan ÖZTÜRK 1
Prof.Dr.Hasan ÖZTÜRK 2
DYNAMICS OF RECIPROCATING ENGINES (INERTIA FORCES)
Using the methods of the preceding section, we begin by locating equivalent masses at the crankpins and at the wrist pin. Thus
For constant angular velocity, α=0the total inertia force (Shaking Force) for all the moving parts. The components in the x and y directions are:
the inertia torque (Shaking Torque) exerted by the engine on the crank shaft is:
3
BALANCING A SINGLE-CYLINDER ENGINE:If it is designate the mass of the counterweight by mc
2ωCm r
2ωAm r
,= +A B CF F F
Prof.Dr.Hasan ÖZTÜRK
Prof.Dr.Hasan ÖZTÜRK 6
BALANCING A SINGLE-CYLINDER ENGINE:If it is designate the mass of the counterweight by mc
2ωCm r
2ωAm r
( )
( )
2 2
2
cos cos2
sin
= − + ω ω + ω ω
= − ω ω
xA C B B
yA C
rF m m m r t m r tl
F m m r t
2 2cos cos 2 , *****( ) = ω ω + ω ω
xB B
rF m r t m r t il
2 3= + =C A A Am m m m
Shaking Force
Primary (First harmonic) Secondary (Second harmonic)
Prof.Dr.Hasan ÖZTÜRK 21
Q1- Examine the balance of the first harmonic forces and moments of a 4 cylinder-2 stroke engine. Firing order is 1-2-3-4. Assume all the slider-crank mechanisms are identical.
Q3- In an in-line six cylinder engine working on four stroke cycle, the cylinder center line are spaced at equal intervals. The firing order is 1-5-6-4-3-2. Draw the secondary crank positions and examine the engine for balance of the secondary forces and couples.