This content is not included in
your SAE MOBILUS subscription, or you are not logged in.
Sensitivity Analysis of the Geometrical Dimensions of the Crankpin Bearing on the Tribological Property of an Engine
Abstract:
Under high-speed working conditions of an engine, the lubrication and
tribological performance (LTP) of the crankpin bearing (CB) are strongly
influenced by the oil film pressure (p) and asperity contact in
the mixed lubrication regime (MLR) of CB, while these parameters mainly depend
on the CB’s geometrical dimensions including the bearing radius
(r
b), bearing width (B), surface roughness
(σ), gap between crankpin and bearing (c),
and crankpin speed (ω). To analyze the sensitivity of the
dynamic parameters of the r
b, B, σ, c, and
ω on the CB’s LTP, a hybrid model of the piston-rod-crank
dynamic and CB lubrication is proposed to establish the dynamic equations of the
CB. An algorithm program written in MATLAB software is then applied to solve the
dynamic equations. The effect of the dynamic parameters of the
r
b, B, σ, c, and
ω on the CB’s LTP is simulated and evaluated via the
indexes of the p, asperity contact force, friction force, and
friction coefficient. The research results show that all the parameters of
r
b, B, σ, c, and
ω of the CB greatly affect the CB’s LTP. To improve the
CB’s LTP, the r
b, B, and σ should be slightly
reduced whereas the c needs to be increased, especially, the
values of 15 ≤ r
b ≤ 20 mm, 10 ≤ B ≤ 15 mm, 2 ≤ σ ≤
4 μm, and 15 ≤ c ≤ 20 μm should be used to optimize the CB’s
LTP. Additionally, the engine speed should be maintained at 2000 rpm to improve
the CB’s LTP. The reduction of the geometric dimensions and the increase of the
engine’s power is being the development trend of the engine manufacturers;
therefore, the research not only elucidates the influence of the CB parameters
on the CB’s LTP but also provides an optimal parameter range of the CB to
further improve the LTP, fuel economy, and friction power loss, and durability
of the engine.