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Rollerized Crank Shafts

Breakthrough of Rollerized Crank Shafts

I. Introduction

II. Tribology in the internal combustion engine

Figure 1 Stribeck curve with static friction, mixed friction and viscous friction

Figure 2 Comparison of friction between a cylindrical roller bearing and a plain bearing

III. Rolling bearings in an internal combustion engine

Figure 3 The use of rolling bearings instead of plain bearings has proven successful in different applications [1]

IV. Development method

Figure 4 Self-contained development process for designing crankshaft bearings [1]

V. Validation

Figure 5 The comparison between the physical engine and the engine model reveals close conformity with the crank angle resolved speed [3]

Figure 6 The measurements and engine model calculations showed a high level of congruence both with and without the vibration damper [1]

Figure 7 Breakdown of friction percentages using a strip-down measurement [1]

Figure 8 Comparison of measured and calculated friction values [1]

VI. Friction-reducing potential

Figure 9 Friction percentages of the four crankshaft main bearings and virtual reciprocal effects [1]

Figure 10 Potential for reducing friction using rolling bearings [1]

Figure 11 Optimally designed rolling bearing for the first crankshaft main bearing in the 1.0-liter three-cylinder engine [1]

Figure 12 The reduced friction attributed to the first crankshaft bearing fitted as a rolling bearing averages out to 1.1 % less fuel consumption in the WLTC [1]

VII. NVH behavior

Figure 13 The subjective analyses revealed that there was no perceptible difference in NVH performance between the engine when fitted with rolling and with plain bearings [1]

VIII. P0 hybridization

Figure 14 The load exerted on the first crankshaft main bearing can be very high, particularly on a P0 hybrid, which means that a rolling bearing mount can measurably reduce fuel consumption [1]

Figure 15 The start sequence of a P0 hybrid application as compared with a plain bearing and a rolling bearing assembly [1]

IX. Conclusion and outlook

The digital version of the Schaeffler Symposium 2018 “Mobility for Tomorrow” conference transcript

I. Introduction

Figure 3 The use of rolling bearings instead of plain bearings has proven successful in different applications [1]

Figure 4 Self-contained development process for designing crankshaft bearings [1]