Fy = −Fn(˛) cos ˛ − Fı (˛) sin ˛ (17)
The initial force of the piston system is written as:
The studied engine is a typical diesel engine, with a peak power at 2500 rpm and peak torque at 2200 rpm。 The applied load to the
Fj = −
。
mpiston +
。 mrodlb 。。 Rw2(cos ˛
l
+ ˛ cos 2˛) (11)
big-end bearing is shown in Fig。 5。
Frc =
(l − lb)mrodrw2 l
2。7。Design of experiments
F (Fg + Fj ) (13)
= cos ˇ
Fı = F sin(˛ + ˇ) (14)
Fn = F cos(˛ + ˇ) − Frc (15)
The bearing load along x, y direction is written as:
Fx = −Fn(˛) sin ˛ + Fı (˛) cos ˛ (16)
Table 1
Engine specifications。
Parameters Unit
Young’s modulus, connecting rod GPa 210
Young’s modulus, crankshaft GPa 210
Poisson’s ratio – 0。3
Connecting rod structure density kg/m3 7800
Piston mass kg 1。943
Piston pin mass kg 1。272
Connecting rod mass kg 2。093
DOE is important as a formal way of maximizing information gained while minimizing required resources, especially for the orthogonal experiment。 It has more to offer than “one change at a time” experimental methods because it allows a judgment on the significance to the output of input variables acting alone。 It is useful to quantify the main effects of the input variables on global responses when optimizing a connecting rod big-end bearing。 In this paper, 10 input variables with 4 different levels (as shown in Table 2), some outputs are selected to evaluate the lubrication per- formances, such as friction power loss, oil leakage, MOFT and MOFP (as shown in Table 3)。
10 input parameters, with 4 levels for each of them, imply a set of 410 runs for the whole experiment with one change at a time。 Every experiment to do the simulation needs at least 1 h, so 410 h are needed to achieve our goal, to overcome this problem, we introduce
Table 3
Bearing response。
Global responses Abbreviation Unit
Connecting rod length mm 219
Center of mass mm 63
Stroke mm 130
Bore diameter mm 126
Crank-pin diameter mm 82
Friction loss FMEP kPa
Minimum oil film thickness MOFT 正交试验回归法和响应曲面法研究连杆英文文献和中文翻译(5):http://www.youerw.com/fanyi/lunwen_101667.html