V ENGINE DESIGN

7/26/2019 V ENGINE DESIGN

1/4

533 TECHNICAL UNIVERSITY OF CLUJ-NAPOCA

ACTA TECHNICA NAPOCENSIS

International Conference on Engineering Graphics and Design

12-13 June 2009

V ENGINE DESIGN

Florian Ion PETRESCU, Relly Victoria PETRESCU

Abstract:V engines in a characteristic aside, their reply kinematics-dynamic (operating in a dynamicviewpoint) is closely linked to constructive parameters of the engine, especially the constructive angle.For this reason, as generally constructive value angle was chosen randomly, after various technicalrequirements constructive or otherwise, inherited or calculated by various factors (more or lessessential), but never got to discuss crucial factor (which takes account of the intimate physiology of themechanism) angle that is constructive with his immediate influence on the overall dynamics of the

mechanism, the actual dynamics of the mechanism with the main engine in the V suffered, the noise andvibration are generally higher compared with the similar engines in line.This paper aims to make a major contribution to remedy this problem so that the engine in V can beoptimally designed and its dynamic behavior in the operation to become blameless, higher than that ofsimilar engines in line. Theoretical calculations are difficult and complex, but the alteration constructiverequired of them is simple, consisting of the imposition of a list of constructive values of the angle from

which you can select the most convenient for each engine builder in V.Key words: Efficiency, force, piston, crank, connecting-rod, motor, stroke, bore, dynamic-velocity,dynamic-acceleration, dynamic-efficiency, V engines, dynamics, kinematics.

1. INTRODUCTION

The V Motors kinematics and dynamics

synthesis can be made optimally by the value of

constructive angle ().For this reason, as generally constructive

value angle was chosen randomly, after various

technical requirements constructive or

otherwise, inherited or calculated by various

factors (more or less essential), but never got to

discuss crucial factor (which takes account of

the intimate physiology of the mechanism)

angle that is constructive with his immediate

influence on the overall dynamics of the

mechanism, the actual dynamics of the

mechanism with the main engine in the V

suffered, the noise and vibration are generally

higher compared with the similar engines in

line.

This paper aims to make a major contribution

to remedy this problem so that the engine in V

can be optimally designed and its dynamic

behavior in the operation to become blameless,higher than that of similar engines in line.

Theoretical calculations are difficult and

complex, but the alteration constructiverequired of them is simple, consisting of the

imposition of a list of constructive values of the

angle from which you can select the most

convenient for each engine builder in V.

2. V MOTORS SYNTHESIS

2.1 PresentationIn the picture number 1 (see the detail in the

picture number 2) one can see the kinematics

schema of the V Engine. The crank 1 has a

trigonometric rotation () and actions theconnecting-rod 2 which moves the piston 3 along

the slide bar B and actions the secondconnecting-rod 4, which moves the second piston

5 along the slide bar D. There is a constructiveanglebetween the two axes B and D.

The same constructive angle () is formed bythe two arms of the connecting-rod 2; first arm

has the length l, and the second (which

transmits the movement to the secondconnecting-rod 4) has the length a; this length


2/4

534a, add with the length b of the second

connecting-rod 4 must gives the length l of the

first connecting-rod.

+

-

O

B

D

A

C

Fm

FBm

FCmFBm

FB

FCm

FCn

FCn

FD

/2--

/2++-

2006 Florian PETRESCUThe Copyright-LawOf March, 01, 1989,U.S. Copyright OfficeLibraryof CongressWashington, DC 20559-6000202-707-3000

V Motors Kinematics and Dynamics Synthesis by the Constructi ve Angle Value ();

Forces Distribution, Angles, Elements and Couples (Joints) Positions; a+b=l

1

2

4

3

5

r

l

a

b

/2 /2

BD

||B

Fig. 1.V Motor Synthesis

The crank motor force Fm is perpendicular at

the crank length r, in A. A part of it (FBm) is

transmitted to the first arm of connecting-rod 2

(along l) towards the first piston 3. An other

part of the motor force, (FCm) is transmitted

towards the second piston 5, by (along) the

second arm of first connecting-rod 2 (a).

)sin(

)](2

cos[

+=

=+=

m

mB

Fx

FxFm (1)

)sin(

]2

cos[

=

=++=

m

mC

Fy

FyFm (2)

2.2 Forces and velocities

A percent (of motor force Fm) x is transmittedtowards the first piston (element 3) and the

percent y is transmitted towards the second

piston (element 5); the sum between x and y is

1 or 100%.

The dynamic velocities have the same

direction like forces:

)sin(

)](2

cos[

+=

=+=

m

mB

vx

vxvm (3)

)sin(

]2

cos[

=

=++=

m

mC

vy

vyvm (4)

From the element 2 (first arm) to the first

piston (element 3) one transmits the force FB

(5) and the dynamic velocity vBD(6).

(5)

cos)sin(

cos

+=

==

m

BB

Fx

FFm

cos)sin(

cos

+=

==

m

BB

vx

vvmD (6)

The kinematics (known) velocity (imposed bythe linkage) is given by the relation 7.

cos

1)sin( += mB vv (7)

To force the first piston velocity equalises the

dynamic value, one introduces a dynamic

coefficient DB(8):

(8)2cos=xDB

Where,

BBB vDv D = (9)

= rvm (10)

The second Motor outline can be solved

now. In C, FCmand vCmare projected in FCnand

vCn:

(11))cos()sin(

)cos(

+=

=+=

m

CC

Fy

FFmn

(12))cos()sin(

)cos(

+=

=+=

m

CC

vy

vvmn

The transmitted force along of the second

connecting-rod (FCn) is projected in D on theD axe in FD:


3/4

535

cos)cos(

)sin(

cos

+

=

==

m

CD

Fy

FFn

(13)

The dynamic velocity in D is:

cos)cos(

)sin(

cos

+

=

==

m

CD

vy

vvn

(14)

The velocity of D imposed by the joint is

(15):

)]sin(cos

)sin(cos[

coscos

+

+

==

a

l

l

vvs mDD&

(15)

2.3 The dynamics coefficientThe dynamic coefficient in D is (16):

+

+=

+

=

=

)sin(cos

)sin(cos

coscos)cos(

)sin()1(

2

a

ln

lxN

n

NDD

(16)

One put the condition to have a single

dynamic coefficient of the mechanism, D:

==

+

++

+=

+

=

===

2

2

2

2

cos

cos)cos()sin(

)sin(coscos

)sin(cos

cos)cos(

)sin(

xDD

l

a

ln

lN

nNxDDD

B

x

x

x

xBD

(17)

The value of x was determined from the

imposed condition to have a single dynamic

coefficient for the mechanism.

3. DYNAMIC ANALYSIS

The dynamic analysis made with the

presented systems indicates some good values

for the constructive angle (), which allow themotor in V works normally without vibrations,

noises and shocks (see the table 1):

Alfa angle values in grad Table 1

[GRAD]0 8

12 1723 25

155 156

164 167

173 179

4. CONCLUSION

With indicate in the table 1 one can make VEngine work without vibrations.

5. REFERENCES

[1] Pelecudi, Chr., s.a. Mecanisme, E.D.P.,

Bucuresti, 1985.

[2] Petrescu, F.I., Petrescu, R.V., Cteva

elemente privind mbuntirea designului

mecanismului motor, Proceedings of 8th

National Symposium on GTD, Vol. I, p.353-358, Brasov, 2003.

[3] Petrescu, F.I., Petrescu, R.V., An original

internal combustion engine, Proceedings of

9th International Symposium SYROM, Vol.

I, p. 135-140, Bucharest, 2005.

[4] Petrescu, F.I., Petrescu, R.V., Determining

the mechanical efficiency of Otto engines

mechanism, Proceedings of International

Symposium, SYROM 2005, Vol. I, p. 141-

146, Bucharest, 2005.


4/4

536

+

-

O

B

D

A

C

Fm

FBm

FCmFBm

FB

FCm

FCn

FCn

FD

/2--

/2++-

2006 Florian PETRESCUThe Copyright-LawOf March, 01, 1989,U.S. Copyright OfficeLibrary of CongressWashington, DC 20559-6000202-707-3000

V Motors Kinematics and Dynamics Synthesis by the Constructive Angle Value ();Forces Distribution, Angles, Elements and Couples (Joints) Positions; a+b=l

1

2

4

3

5

r

l

a

b

/2 /2

BD

||B

Fig. 2.V Motor kinematics schema

DESIGNUL MOTOARELOR N V

Rezumat:Motoarele n V au o caracteristicaparte, rspunsul lor cinematico-dinamic (funcionarea lor din punct devedere dinamic) fiind strns legat de parametrii constructivi ai motorului, n special de valoarea unghiului constructiv.

Din acest motiv, cum n general valoarea unghiului constructiv a fost aleas aleator, dup diferite cerine tehnico-constructive ori de alt natur, motenite sau calculate dup diferii factori (mai mult sau mai puin eseniali), darniciodatnu s-a luat n discuie factorul hotrtor (care ine cont de fiziologia intima mecanismului) adic unghiulconstructiv cu influena lui nemijlocitasupra dinamicii mecanismului per ansamblu, dinamica reala mecanismuluiprincipal mpreuncu cea a motorului n V a avut de suferit, nivelul zgomotelor i vibraiilor fiind n general mai ridicatcomparativ cu motoarele similare n linie. Prezenta lucrare i propune s aduc o contribuie major la remediereaacestei probleme, astfel nct motorul n V spoatfi proiectat optim, iar comportamentul su dinamic n funcionare s

devin ireproabil, superior celui al motoarelor similare n linie. Calculele teoretice sunt dificile i complexe, nsmodificarea constructivcerutde ele, este simpl, constnd n impunerea unei liste de valori ale unghiului constructiv,din care se poate selecta valoarea cea mai convenabilpentru fiecare constructor de motoare n V.

Florian Ion Petrescu, PhD. Eng. Assistant Professor at Polytechnic University of Bucharest, TMRDepartment (Theory of Mechanisms and Robots Department), [email protected],

0214029632.

Relly Victoria Petrescu, PhD. Eng., Lecturer at Polytechnic University of Bucharest, GDGIDepartment (Department of Descriptive Geometry and Engineering Graphics),

[email protected], 0214029136.

V ENGINE DESIGN

Documents

Transcript of V ENGINE DESIGN