Đang tải...

Chúc các cụ buổi tối ấm áp!

"Hãy lao động nhiều hơn tất cả mọi người, nhưng hãy nói về bản thân mình ít hơn tất cả mọi người."

Cơ bản Các đơn vị , thông số , ký hiệu trong tính toán động cơ đốt trong!

Thảo luận trong 'Động cơ' bắt đầu bởi otohui, 22/10/11.

Thành viên đang xem bài viết (Users: 0, Guests: 0)

  1. otohui
    Offline

    otohui Tài xế O-H

    Tham gia ngày:
    24/3/09
    Số km:
    2,366
    Được đổ xăng:
    119
    Xăng:
    -879 lít xăng

    Cylinder Swept Volume (Vc):
    where:
    Vc= cylinder swept volume [cm3 (cc) or L]
    Ac = cylinder area [cm2 or cm2/100]
    dc = cylinder diameter [cm or cm/10]
    L = stroke length (the distance between the TDC and BDC) [cm or cm/10]
    BDC = Bottom Dead Center
    TDC = Top Dead Center
    * Increase the diameter or the stroke length will increase the cylinder volume, the ratio between the cylinder diameter/cylinder stroke called “bore/stroke” ratio.

    - “bore/stroke” >1 is called over square engine, and is used in automotive engines

    - “bore/stroke” =1 is called square engine

    - “bore/stoke” <1 is called= under square engine, and is used in tractor engine

    Engine Swept Volume (Ve):
    where:
    Ve = engine swept volume [cm3 (cc) or L]
    n = number of cylinders
    Vc = cylinder swept volume [cm3 (cc) or L]
    Ac = cylinder area [cm2 or cm2/100]
    dc = cylinder diameter [cm or cm/10]

    * The units of cylinder swept volume is measured in (cm3, cubic centimeter (cc), or liter)

    - Ve for small engines, 4 cylinder engines is (750 cc:1300 cc)

    - Ve for big engine, 8 cylinder engines is (1600 cc:2500 cc)

    Compression Ratio (r):

    where:

    r = compression ratio

    Vs = cylinder swept volume (combustion chamber volume) [cc, L, or m3]

    Vc = cylinder volume [cc, L, or m3]

    * Increase the compression ratio increase engine power

    - r (gasoline engine) = 7:12, the upper limit is engine pre ignition

    - r (diesel engine) = 10:18, the upper limit is the stresses on engine parts

    Engine Volumetric Efficiency (hv):

    where:

    hV = volumetric efficiency

    Vair = volume of air taken into cylinder [cc, L, or m3]

    Vc = cylinder swept volume [cc, L, or m3]

    * Increase the engine volumetric efficiency increase engine power

    - Engine of normal aspiration has a volumetric efficiency of 80% to 90%

    - Engine volumetric efficiency can be increased by using:

    (turbo and supper charger can increase the volumetric efficiency by 50%)

    Engine Indicated Torque (Ti):

    where:

    Ti = engine indicated torque [Nm]

    imep = indicated mean effective pressure [N/m2]

    Ac = cylinder area [m2]

    L = stroke length [m]

    z = 1 (for 2 stroke engines), 2 (for 4 stroke engines)

    n = number of cylinders

    θ = crank shaft angle [1/s]

    Engine Indicated Power (Pi):

    where:

    imep = is the indicated mean effective pressure [N/m2]

    Ac = cylinder area [m2]

    L = stroke length [m]

    n = number of cylinders

    N = engine speed [rpm]

    z = 1 (for 2 stroke engines), 2 (for 4 stroke engines)

    Vc = cylinder swept volume [m3]

    Ve = engine swept volume [m3]

    Ti = engine indicated torque [Nm]

    ω = engine angular speed [1/s]

    Engine Mechanical Efficiency (hm):

    where:

    hm = mechanical efficiency

    Pb = engine brake power [kW]

    Pi = engine indicated power [kW]

    Pf = engine friction power [kW]

    Engine Specific Fuel Consumption (SFC):
    where:
    SFC = specific fuel consumption [(kg/h)/kW, kg/(3600 s x kW), kg/(3600 kJ)]

    FC = fuel consumption [kg/h]

    Pb = brake power [kW]

    Engine Thermal Efficiency (hth):

    where:

    hth = thermal efficiency

    Pb = brake power [kW]

    FC = fuel consumption [kg/h = (fuel consumption in L/h) x (ρ in kg/L)]

    CV = calorific value of kilogram fuel [kJ/kg]

    ρ = relative density of fuel [kg/L]
     

Chia sẻ trang này