Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

[V-Tec]

Re: 1998 Honda S2000

1998 Honda S2000

87.00mm × 84.00mm
3.43 in × 3.31 in
243.3 PS (240.0 bhp) (179 kW)
@8300 rpm
Cm=0.167x3.31x8300=4587.99 ft/min
Very short life !

Ovo mi nije jasno jer se za ovaj motor prica da je veoma dobro izbalansiran i pouzdan.

P.S.

Dacia Logan 1.6 mpi
Prečnik x hod klipa (mm) 79,5x80,5
Najveća snaga kW (kS) 64(90) @ 5500 o/min
Najveći obrtni moment (Nm) 128 @ 3000 o/min

80,5(hod klipa) x 5500(max o/min) / 30000 = 14,758 Dobro!

X<17.77 dobro
17.77<X<20.31 napregnut motor, potrebna dobra konstrukcija
X>20.31 lose

Na 6200 o/min(blokada) je 16,636

[sw.brick]

za ovaj motor

posto si odabrao da ce se taj motor voziti po pravilu sa 8300 obrtaja, takvi su i rezultati.

ali, retko ko ce voziti taj auto i taj motor sa 8300 obrtaja, osim u vrlo kratkim intervalima tokom menjanja brzina.

po meni, logicnije je uzeti broj obrtaja motora za rezim voznje kakav je najcesci kod doticne osobe.
obicno je to 2500-4000 obrtaja najcesci opseg broja obrtaja svakodnevne voznje, tj voznje u kontinuitetu vise sati.

[X9]

za moj motor:



Mean Piston Speed

- V6 Engines - all-alloy DOHC 24V 60-degree V6 configuration
- Split Crankcase - as 911 flat-6 offers increased rigidity over traditional bearing-cap solutions for high-rpm capability (7800rpm 2.0V6) and low NVH (winning 1992 German engine award)
- Bearings - 4-bolt Mains, with a further pair of bolts at each bearing section. Key journals & bearings are oversized regarding width. Bearings are triple-layer heavy duty
- Crankshaft - Forged, nitrided, triple-lapped, mirror-finished
- Piston Squirters - Upper bearing journals contain piston oil-squirters to aid cooling
- Exhaust-Valves - Stainless steel & sodium cooled
- Pistons - Lightweight to reduce reciprocating mass, piston skirts are moly coated to reduce friction
- Head Gaskets - Stainless steel is used, with torque-to-yield bolts
- Stroke - Very short stroke creates low crank angles & low rod/bearing loads
Engine Dynamic Stress Levels
o Mean Piston Speed, MPS
- 2.5V6 MPS = 0.167 * 2.92 * 7000 = 3170 ft/min at 7000rpm
o Ring Loadings
Top-rings must balance high-rpm capability and wear, a thin ring allows high-rpm capability, too thin and wear becomes an issue. With reduced crank angles from a short stroke ring wear is reduced. A 1.5mm ring is beneficial over a 1.0mm ring for high-rpm.

Maximum-Piston-Acceleration (MPA):
2.5 top-ring - 1.49mm/0.06"
- MPA Permitted = 77,000ft/sec^2
- MPA Experienced = 51,354ft/sec^2 at 7000rpm
- The BMW M5 in comparison experiences MPA of 90,000ft/sec^2 on a 1.5mm ring
Lighter rings create reduced accelerative forces, reduced ring/piston interface overheating and reduced hammering of the piston-ring-groove. Too light and ring longevity is adversely affected
2.5 rod-centre-dist = 138mm; stroke = 74.2mm; A = 1.87
- MPS-2.5 = (7500^2*2.92/2189)*(1.2*1.87) = 70,157 ft/sec^2
Both the 2.5V6 & 2.0I4 engines are engineered for longevity. The 2.5 engine is likely to be the longer lived engine subject to identical maintenance to the 2.0 engine. Mazda V6 engines are assembled entirely by robots, not humans, at the Osaka engine plant in Japan alongside Rotary engines.

Ford bench testing, with very minor changes, showed the V6 to be capable of continuous running at 8900rpm - well beyond redline 7500rpm.

SAE paper "SAE920677" covers detailed design of the engine.
"After 300,950 miles the Mazda MX6-V6 passed an IM 240 Exhaust Emission Test in Aurora, Colorado, with results well within new car limits. At more than 310,000 miles, the test engine was disassembled for inspection and measurement. No wear was evident on valve stems and guides, main and rod bearings, crankshaft main and rod journals, or cylinder walls. The cylinder hone marks from original factory machining were all clearly evident. While piston skirts showed no wear, piston rings showed an average of only 0.0015" of face wear."
over and out

[Damjan156]

Evo šta meni kaže:Alfa Romeo 156 2.0TS 99-o godište

83x91mm
3.27x3.58 in
155.1 PS (153.0 bhp) 114.1kW @6400

cm=0.167 x L x N

cm=0.167 x 3.58 x 6400@

cm=3826 ft/min

a blokada na 7500@ onda izgleda ovako 4487 ft/min
LUDILO! A jos sledi chip tuning,he,he!

[siki]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

Da vidimo jeli moja računica tačna:84.00 mm × 90.00 mm
3.31 in × 3.54 in onda idemo: 0,167 x 3,54 x 5600=3.310 jel to dobro
ako ga žešće vrtim na 6000 o/min onda je rezultat 3.547 .molim komentar onoga koje pustio formulu.
Inače u pitanju je motor od 2.0 lit 4 cil 16 ventila turbo 2 litre
1995 cc
(121.742 cu in)207.8 PS (205.0 bhp) (152.9 kW)
@ 5600 rpm
Specific output 102.8 bhp/litre
1.68 bhp/cu in
Maximum torque
(DIN) 298.0 Nm (220 ft·lb) (30.4 kgm)
@ 2750 rpm
bmep 1877.1 kPa (272.2 psi)
Specific torque 149.37 Nm/litre

[kilson]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

nder 3,500 ft/min Good reliability
3,500-4,000 ft/min Stressful, needs good design
Over 4,000 ft/min Very short life

Sta ti nije jasno u celoj prici? Losi rezultati kazu da motore dugog hoda ne treba siliti sa "navrtanjem" po crvenom polju zbog velike brzine klipa. Sto se tebe tice, miran si i na 6000 rpm, ali ne znam sta ce ti 6000 rpm obzirom da vozis fabricki FI motor.

[siki]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

Hvala lepo Kilsone ,malo sam brinuo jer volim da opalim po gasu-normalno na autoputu-Znači izračun je tačan ako se ne varam po tvom odgovoru,a šta ti znači FI motor

i ako nije tajna ono ispod koji je bio auto na 7000 o/min.

[kilson]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

FI - forced induction Samo ti uredno odrzavaj tu makinu i nema problema.

[off] Ovo 7000 rpm je interna fora u vezi prenosnih odnosa na jednoj matoroj drtini...

[Raverick]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

Fiat Ritmo 105 TC
1.6 DOHC 8v-77kW
84x71.5mm
3.31x2.81in
105bhp@6100rpm

0.167x2.81x6100=2862,547 ft/min
Good reliability

[charjek]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

ajd sad ovako ko zna da izracuna
Skoda 120 LS 1980god hod klipa 72/72
43 kw
i sta vam jos treba,jer koliki obrtni je momenat nemam pojma
ajd vidim ja moju taljigu kakva je

[nikolicji]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

Honda prelude 1986 1.8 dualcarb 80x91

@4000 rpm (max torque 155 Nm) 12.133 m/s
@5500 rpm (max power 107.5 PS) 16.683 m/s
@6200 rpm (redline start) 18.807 m/s
@8000 rpm (max mark teoretski) 24.267 m/s

[senzacija]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

Renault Clio RN 1.4 Energy

75.80mm x 77mm (2.98in x 3.03in)
81.1 PS (80 bhp) (59.7 kW) pri 5750 rpm
Cm=0.167x3.03x5750=2910 ft/min

Good reliability

[cedo86]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

Ford Mondeo Mk3 2.0 TDCi

86 x 86mm ili 3.39 x 3.39in
96kW@ 3500o/min

Cm=0.167x3.39x3500 =1981ft/min ili 10.1m/sec

[YUgisa]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

S=hod klipa (eng. stroke)[mm]
B=max. br. obrtaja u minuti (rpm)[o/min]
X=brzina klipa[m/s]

X=S*B/30.000

Pa sad:
X<17.77 dobro
17.77<X<20.31 napregnut motor, potrebna dobra konstrukcija
X>20.31 lose

Yugo 1.1 i 1.3 Hod 55.5 mm

X=55.5x9500/30.000

X=17.575

[Desmo]

Re: Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

Mislim da grešite u računanju kod obrtaja, u formuli se za broj obrtaja uzima vrednost "factory redline" - maksimalni broja obrtaja.

Broj obrtaja na kojim motor isporučuje najviše snage je manji od maksimalnog broja obrtaja.