Manufacturing Processes Report(发动机制造工艺)

Manufacturing Processes

Contents:

Introduction 2 Engine block 2-4 Crank Shaft 5-9 Connecting rod 10-14 Conclusion 15 Appendices 16

Introduction:

There are thirteen parts in the engine as shown in above figure, I will discuss three parts of the engine. Engine block, Crankshaft and Connecting rod.In the following section, I will discuss the function, material used, mechanical properties of the part, the quality requirements and the process used of producing those parts.

Engine block:

1-1 Description:

The Engine Block is a single unit that contains all the pieces for the engine. The block serves as the structural framework of the engine and carries the mounting pad by which the engine is supported in the chassis . The block is made of cast iron and sometimes aluminum for higher performance vehicles. The engine block is manufactured

to withstand large amounts of stress and high temperatures.

1-2. Production requirements:

The Internal design of the engine block must be extremely precise, because all parts must fit and be able to function properly once the entire engine is assembled. The outside design of the engine only has to fit fewer requirements like attaching to the car properly. Engines are made in all different shapes and sizes to fit inside the frame of the car, therefore a company must be able to manufacture many different engine block designs yet keep up with product demand. There are 6000-8000 engine blocks made a day at a highly qualified company, this may be for many different models.

1-3. Process Requirements:

The Engine block goes through two manufacturing processes before it is ready for assembly. The first process is die casting manufactured

using cast iron. The strength of the piece depends on the type of iron used and if any other materials are added. The higher strength iron alloys can include Molybdenum, Chrome or Copper for increased strength.

For the engine block the hot-chamber process is used. This process uses a die cut into three parts then combined using a large amount of pressure and temperature. Two parts of the die will contain extrusions to produce holes and cavities. This eliminates much machine process and saves time. Then all the die parts are forced together with the material inside to produce the engine block cast. Once the part has been casted then cooled (using a chill plat) the second process may be preformed. This processes is machining and is very important the overall performance of the engine.

The first machining process is to bore out the cylinders for the pistons and then for the camshaft. Next the cylinders need to be sleeved; this provides the surface with a small gradient to trap an oil film. The next operation is to grind down and area for the bearing to set in, this does not have to be surface finished because bushings will be set down in first. The next operation is end milling. This will provide a smooth surface finish for the joining of the oil pan, the crankshaft cap and areas for mounting. The final operations include drilling, reaming and taping. These provide locations for the engine block to be mounted.