Automotive and Tractors Engineering Dept.

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Vehicle Design (2) Course Lecture 11

Automotive and Tractors Engineering Dept.

Fcualty of Engineering, Minia University

Automotive and Tractors Engineering Dept .

4^th Year Auto .

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4^th Year Auto .

Cranktrain

1. Definition of Cranktrain Function 2. Crankshaft Configurations

3. Connecting Rod Configurations 4. Flywheel Configurations

 Outline of the present subject

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4^th Year Auto .

1. Definition of Cranktrain Function

The Cranktrain is at the heart of the reciprocating piston engine, and its purpose is to translate the linear motion of the pistons into rotary motion for the purpose of extracting useful work. The cranktrain is typically composed of connecting rods, the crankshaft, and a flywheel or power takeoff device.

Crankshaft terminology

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4^th Year Auto .

Connecting rod terminology

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4^th Year Auto .

Crankshaft and Connecting Rod Configurations

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4^th Year Auto .

Detailed Design of Crankshaft Geometry

The geometry of a crankshaft is complicated, and the loading varies as a function of its rotational position. Because of the dissimilar cross-sections of the crankshaft, it will be sensitive to discontinuities in stiffness. It is at these stiffness discontinuities that stress will be concentrated. Generally, the crankshaft fillet will be the most highly stressed area and will require the most detailed design attention as the materials used to make crankshafts are typically sensitive to notch factors.

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4^th Year Auto .

Initial sizing values

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Forces transmitted to crankshaft at each cylinder versus crank angle

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4^th Year Auto .

Untuned viscous shear damper operation

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4^th Year Auto .

Tuned damper operation

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4^th Year Auto .

Crankshaft nose design and assembly details

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4^th Year Auto .

Automotive and Tractors Engineering Dept.

Vehicle Design (2) Course Lecture 11