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

  1. #1
    Član od
    02.10.2004
    Lokacija
    Valjevo, Srbija
    Garaža
    PEUGEOT 206 XS 1.6
    Poruke
    1.049

    Izracunajte izdrzljivost motora, obrtaji i vek trajanja...

    Uvreženo je mišljenje da motori koji se "radije" vrte kraće traju. Da se ipak radi o vise parametara vidi se iz jednog nepotpisanog usenet posta koji se referirao na Gordon Jenning's-ovu "Two stroke tuner's handbook". Naravno, u prvom planu je BMW.

    John Allen commented on the higher redline and longer stroke
    of the '91-'93 M5 engine:
    >It's interesting that the longer-stroke motor (S38B36) also
    >has the higher redline. Any thoughts?

    John,

    Yes, I can give you some "rules of thumb" about engine
    reliability versus rpm. I happened to research this some
    during the past week, so your question is timely.

    The Metric Mechanic (MM) Catalog got me started with its
    section on engine rpm versus life. Basically, high rpm
    operation wears out engines faster, but there's more to it
    than that. MM also mentions the critical top piston ring
    area.

    This sounded very familiar -- so familiar that I searched my
    attic for Gordon Jenning's "Two Stroke Tuner's Handbook".
    Now, M5s have four stroke engines, but the basics of pistons
    and rings are the same for either.


    Mean Piston Speed
    - -----------------
    The best known "rule of thumb" is mean piston speed (average
    speed the piston travels at a fixed rpm). It goes like
    this:

    Mean Piston Speed Result
    ------------------ ------
    Under 3,500 ft/min Good reliability
    3,500-4,000 ft/min Stressful, needs good design
    Over 4,000 ft/min Very short life


    Mean piston speed is easy to determine. It's based on the
    piston stroke and rpm.

    Cm = 0.167 x L x N

    Cm = mean piston speed in feet per min
    L = stroke in inches
    N = crankshaft speed in rpm

    Using the 1988 E28 M5 as an example:
    E28 M5, Bore and stroke 3.68 x 3.31 in (93.4 x 84 mm)
    At 6,900 rpm (factory redline)

    Cm = 0.167 x 3.31 x 6900 = 3,814 ft/min

    At 7,200 rpm (Dinan chip redline) = 3,980 ft/min
    At 6,500 rpm (max constant speed) = 3,593 ft/min

    Here are some other piston speeds I figured for comparison.

    Redline Stroke Piston Speed
    Engine (rpm) in,mm (ft/min)
    -------- ------- -------- ------------
    BMW 2002 6,400 3.15, 80 3,367
    BMW 318i 6,500 3.19, 81 3,463
    BMW 325i 6,500 2.95, 75 3,202
    BMW 3.0 6,400 3.15, 80 3,367
    BMW 535i 6,200 3.39, 86 3,510

    MM 4000 6,000 3.70, 94 3,707
    MM 3500 6,400 3.39, 86 3,623

    BMW E36 M3 6,800 3.38, 85.8 3,838
    BMW E28 M5 6,900 3.31, 84 3,814
    BMW E34 M5 7,200 3.39, 86 4,076

    CBR600 13,250 1.78, 45.2 3,939 (motorcycle)

    Notice that most production cars stay below 3,500 ft/min,
    while the E36 M3 has the same 3,800 ft/min piston speed as
    the E28 M5. With its longer stroke, the E34 M5 piston speed
    is even higher than the screaming Honda CBR600 motorcycle!
    The two Metric Mechanic (MM) engines also go above 3,500
    ft/min.

    >From the MM Catalog Engine Specification table, MM uses
    thinner (lighter) 1.5 mm (0.059 in) top rings than the standard
    BMW 1.75 mm (0.069 in) top rings. Lighter weight reduces
    vertical ring acceleration force at high rpm. MM talks
    about less "hammering" of the ring groove from the lighter
    ring, but it also reduces piston and ring overheating.

    Recommendations
    - ---------------
    Engines last a lot longer if they're never run at redline,
    but what's the point. Enjoy your M-car. Considering piston
    speed and acceleration calculations and ring thickness, M5
    engine design allows reasonable reliability under high
    engine revs, but the word "understressed" doesn't come to
    mind.

    My suggestion is be most careful about sustained high
    (redline) rpms. It's probably okay to shift at redline, but
    don't hold it there very long, because the pistons and rings
    may suffer.

    If you have a Dinan chip, maybe shift at the factory
    recommended redline (6,900 versus Dinan 7,200 rpm). Even
    shifting at 7,200 rpm won't cause any immediate
    consequences, but over time it causes extra wear.



    Postoji još i dodatak o principu rada karika, kako dolazi do njihovog pregrevanja, te zavisnosti debljine karike o brzini vrtnje klipa, ali to ce ici nekom drugom prilikom.
    Primer:
    Evo kako to izgleda za BMW 320i E36;
    Cm = 0.167 x L x N;
    Cm = 0,167 x 2,6 x 6700 = 2,910 ft/min ili ti good reliabillity
    Podatke za L (hod (stroke) u inchima) i N (max obrtaje vrtnje) za svoje ljubimce mozete potraziti na
    www.carfolio.com

  2. #2
    Član od
    30.09.2004
    Lokacija
    Čačak, Srbija
    Poruke
    3.034
    Ovi parametri kojima ti izražavaš izdržljivost mašine u potpunosti stoje.Odavno je već brzina kretanja klipa dovedena u funkciju sa izdržljivošću i trajnošću motora.Voleo bih kad bi mogao da postaviš ove parametre za nekoliko auta koji važe za izdržljive i one druge, neki bi se iznenadili rezultatima.Naime dešava se da mašina koja ima visoke brojeve obrtaja motora ima umerenu brzinu klipa odnosno spada u one pouzdanije i izdržljivije konstrukcije!Ostalo je na vozaču i održavanju!
    Uz laž uvek ide istina, istina je dovoljna sama!

  3. #3
    Član od
    02.10.2004
    Lokacija
    Valjevo, Srbija
    Garaža
    PEUGEOT 206 XS 1.6
    Poruke
    1.049

    Fiat Idea 1.3 16v Multijet

    Fiat Idea 1.3 16v Multijet

    Precnik i hod klipa: 69.60mm × 82.00mm (2.74 in × 3.23 in) L=3.23
    Max. snaga: 70 PS (69.0 bhp) (51.5 kW) pri 4000 rpm N=4000
    Cm=0.167x3.23x4000=2157.64 ft-min

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

    Cm=2157.64 ft/min Good reliability (Dobra pouzdanost)

  4. #4
    Član od
    02.10.2004
    Lokacija
    Valjevo, Srbija
    Garaža
    PEUGEOT 206 XS 1.6
    Poruke
    1.049

    Zastava Yugo 55A

    Zastava Yugo 55A

    Precnik i hod klipa: 80.00mm × 55.50mm (3.15 in × 2.19 in)
    Maksimalna snaga: 56.8 PS (56.0 bhp) (41.8 kW)@6000 rpm
    Cm=0.167x2.19x6000=2194.38 ft/min Good reliability
    [/b]

  5. #5
    Član od
    02.10.2004
    Lokacija
    Valjevo, Srbija
    Garaža
    PEUGEOT 206 XS 1.6
    Poruke
    1.049

    Peugeot 206 GTI 2.0-16V

    Peugeot 206 GTI 2.0-16V

    85.00mm × 88.00mm (3.35 in × 3.46 in)
    137.9 PS (136.0 bhp) (101.4 kW)@6000 rpm

    Cm=0.167x3.46x6000=3466.92 ft/min
    Dobro ali na samoj granici da bude 3500 ft/min Stressful, needs good design

    p.s. jeste da sam sebi uskacem u usta
    ali ipak Peugeot voznja vaseg zivota

  6. #6
    Član od
    02.10.2004
    Lokacija
    Valjevo, Srbija
    Garaža
    PEUGEOT 206 XS 1.6
    Poruke
    1.049

    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 !

  7. #7
    Član od
    15.10.2004
    Lokacija
    London
    Poruke
    2.399

    Re: Zastava Yugo 55A

    Citirati Originalno postavljeno od gordi014
    Zastava Yugo 55A

    Precnik i hod klipa: 80.00mm × 55.50mm (3.15 in × 2.19 in)
    Maksimalna snaga: 56.8 PS (56.0 bhp) (41.8 kW)@6000 rpm
    Cm=0.167x2.19x6000=2194.38 ft/min Good reliability
    [/b]
    U mnogo primera u praksi je dokazano da ovo nema veze sa zivotom.

    Taman sam razmisljao da uradim za moj auto, ali kad sam video ovo, odustao sam.

  8. #8
    Član od
    02.10.2004
    Lokacija
    Valjevo, Srbija
    Garaža
    PEUGEOT 206 XS 1.6
    Poruke
    1.049

    1999 Saab 9-3 2.0 Turbo

    1999 Saab 9-3 2.0 Turbo
    90.00mm × 78.00mm
    3.54 in × 3.07 in
    202.8 PS (200.0 bhp) (149.1 kW)
    @5500 rpm
    Cm=0.167x3.07x5500=2819.79 ft/min
    Good

  9. #9
    Član od
    02.10.2004
    Lokacija
    Valjevo, Srbija
    Garaža
    PEUGEOT 206 XS 1.6
    Poruke
    1.049
    Evo probajte i sami podatke imate na sajtu i odaberite zemlju i model automobila:
    http://www.carfolio.com/specifications/

  10. #10
    Član od
    29.09.2004
    Lokacija
    Gislaved//Sweden
    Garaža
    SAAB 9000 AERO R; SA
    Poruke
    8.726
    Unosi bloga
    1
    OK.. da sad malo uletim sa metrickim jedinicama.

    3500 ft/min = 17,77 m/sec

    4000 ft/min = 20,31 m/sec

    4500 ft/min = 22,86 m/sec


    Lakse za porediti.
    Att mäta är att veta...to measure is to know...meriti je znati..
    move your mind

  11. #11
    Član od
    29.09.2004
    Lokacija
    Gislaved//Sweden
    Garaža
    SAAB 9000 AERO R; SA
    Poruke
    8.726
    Unosi bloga
    1

    Re: 1999 Saab 9-3 2.0 Turbo

    Citirati Originalno postavljeno od gordi014
    1999 Saab 9-3 2.0 Turbo
    90.00mm × 78.00mm
    3.54 in × 3.07 in
    202.8 PS (200.0 bhp) (149.1 kW)
    @5500 rpm
    Cm=0.167x3.07x5500=2819.79 ft/min
    Good
    Ovde vidis da se na 6826 rpm dolazi do 3500ft/min.
    Motor ima max out power na 5500 a blokiran je na 6180 rpm.
    Marginal je ostao.

    Motor koji sam pravio je u sustini te geometrije sa klipovima iz generacije
    niskofrikcionih gde su karike niskofrikcionog tipa, tako da imam malo marginala.

    Fiat motori umaju upravo jedan nivo niskog stresa gde se upravo sredja brzina klipa drzi veoma nisko.

    Odatle i dokazana prica o F128 motorima koji sahranjuju karoserije.
    Att mäta är att veta...to measure is to know...meriti je znati..
    move your mind

  12. #12
    Član od
    29.09.2004
    Lokacija
    Gislaved//Sweden
    Garaža
    SAAB 9000 AERO R; SA
    Poruke
    8.726
    Unosi bloga
    1

    Re: Zastava Yugo 55A

    Citirati Originalno postavljeno od BRABUS
    Citirati Originalno postavljeno od gordi014
    Zastava Yugo 55A

    Precnik i hod klipa: 80.00mm × 55.50mm (3.15 in × 2.19 in)
    Maksimalna snaga: 56.8 PS (56.0 bhp) (41.8 kW)@6000 rpm
    Cm=0.167x2.19x6000=2194.38 ft/min Good reliability
    [/b]
    U mnogo primera u praksi je dokazano da ovo nema veze sa zivotom.

    Taman sam razmisljao da uradim za moj auto, ali kad sam video ovo, odustao sam.
    Eh.. nabavi klipove od Fiata , ne iz nase domace radinosti, i karike takodje, a tvrdo hromiranje cilindra je kod nas jos uvek OK, manda ne kao sto je kod Fiata.
    Att mäta är att veta...to measure is to know...meriti je znati..
    move your mind

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