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Automobile Design-Frame Designs

The vehicle frame is the basic platform to which all suspension and steering linkage parts attach. A vehicle will neither steer nor handle well if the frame is too flexible. A rigid frame structure may pass unnecessary vibrations into the passenger compartment. The frame and suspension design will affect the ride quality, handling, and durability, as well as the levels of both noise and vibration.

Manufacturers use several different types of construction on their vehicles. Of these, separate body and frame construction was the most common through the 1970's. It is still used in large vans, pickups, and trucks. In this type of construction, the engine, drive line, running gear, and body mount to the frame through insulators. Insulators are synthetic rubber pads that keep road and engine noise and vibration from going into the passenger compartment.

A second type of construction is the unitized body. This, design is by far the most popular in modern vehicles. The unitized design has a lightweight structure with the required strength. Tn this type of construction, the frame is welded into the body as part of the body structure. Body panels add strength to the frame pieces. The running gear and drive line are mounted to the unitized body through large, soft synthetic rubber insulators. The insulators minimize the transfer of noise and vibration. If the insulators are too soft, they will allow too much running gear and drive line movement. This movement, called compliance, affects vehicle handling and control. If the insulators are too hard, they will not insulate noise and vibration as they should. The manufacturer carefully designs the insulators and puts them where they will be in a vehicle with low noise and vibration transmission that still has proper handling and feel. Insulator properties change with age, changing original characteristics as the vehicle becomes older.

A third type of construction combines the features of the first and second types. It uses a stub frame from the bulkhead forward and a unitized body from the bulkhead back. The unitized part is very rigid, while the stub frame provides a place for good insulation.

Manufacturers select the type of construction .that is most economical to build,' while providing the noise, vibration, and ride and handling characteristics they want in the vehicle. Large older vehicles, vans, and trucks generally use separate body and frame construction. The newer, smaller' vehicles generally use unitized construction.

The machine piston connecting rod set

The piston connecting rod set is composed of the piston, piston wreath, piston pin, connecting rod, connecting rod axle bush, etc.

effect: The effect of the piston is to bear the air pressure, and pass to connecting rod to drive the bent axle to revolve through connecting rod axle bush, the piston coping is still a part of the burning room. The work condition: Piston works under the condition of heat, high pressure, high speed, and bad lubrication .Piston directly contacts with the heat air. The temperature can amount to above 2500 Ks in a moment .The piston is heated severely, but the condition of spreading the hot is bad .So while the piston works, the temperature is very high and the coping is up to the 600-700 Ks: And the temperature distributes asymmetrically; The piston coping bears great air pressure, especially the pressure is greatest in the route of doing efficacy. The gasoline machine is up to the 3-5MPas, the diesel engine is up to the

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6-9MPas.This makes the piston produce pound, and bear the function of the side pressure. Therefore, the piston should have enough heat-proof, try to decrease the heating area,, strengthen the cooling of the piston, to make the highest temperature of the coping descend .The piston moves at very high speed(8-12 ms/ s) back and forth in the air cylinder, and speed changes constantly, This produces very great inertial dint, making the piston bear great additional load working under such bad condition, the piston will become deformed heating power. At the same time ,it slitters the chemical corrosive power of the burning gas .In order to descend the inertial dint of back and forth, we must ease the weight of the piston as possible .Piston works under the condition of the heat, high pressure, high speed(the average speed can amount to the 101115 m/ s), and its lubricant condition is bad and the frication between the piston and the air cylinder wall is very great. In order to descend the friction, the surface of the piston surface must be wear-resistant..

Request:

1) To have enough rigidity and strength, and the reliable dint;

2) Transmit heat well, bear the high pressure, bear the heat and bear to wear away;

3) the quantity is small, the weight is light, descend the inertial dint of back and forth as possible

The aluminum metal alloy material satisfies the top requests basically, therefore, the piston generally adopts the high strength aluminum metal alloy, but some low speed diesel engines adopt high class iron casting or heat-proof steel

structure: The piston can be divided into three parts, piston coping, the piston head and piston skirt departments.

1. The piston coping

The piston coping bears the air pressure, it is a part of the burnable room .Its shape, position, size are relevant to the concrete from of the burnable room. They are made to satisfy the combustible hybrid spirit formation and burnable requests. Its coping shape can be divided into four major types, a flat coping piston, a convex coping piston, a concave coping piston and model piston.

A convex coping piston is usually used on the two blunt distance I.C. engines, It is good to improve the process exchanging the gas .Modern four blunt the distance gasoline machine also adopts the convex coping piston in order to strengthen the effect of pushing the gas or extend the ratio of compressing .Convex of a piston coping presents a form of ball, its coping strength is high, having an effect of leading, being advantageous to improve the process of exchanging the gas, two route of travel gasoline machines often adopt the convex coping piston

A piston coping presents the hollow form, the shape and positions of the cave pit must be advantageous to the combustion of the combustible and hybrid gas, having a pair of eddies concave pit ball, concave pit, U concave pit, and so on.

2. Piston head

The piston refers to the first piston wreath to the part above the piston pin.It has several wreath slots, which are used to install the piston wreath and have an effect of sealing completely. It is also called the leak proof department .The diesel engine’s compress ratio is high, and generally have four wreath slots, The three upper wreaths are used to install, the lower part installs the oil wreath. The gasoline machine has three wreath slots generally,

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which are two jet of gas wreath slots and an oil wreath slots. At the bottom of oil wreath slot many paths toward eyelet are drilled to make the quilt oil wreath flow from the air cylinder wall to the oil bottom hull through these eyelets. The working condition of the wreath slot is the worst and should leave the coping generally a little farther.

Above the gas wreath, a narrow insulating slot is usually set to cut off the heat flow which is spread from the piston coping to the first gas wreath and make parts of calories from a piston wreath spread, thus easing the hot burden of the first gas wreath. On some engines small wreathe slots are often made between the coping head and the first gas wreathe, sometimes till a few more wreath. This kind of small wreath can adsorb the lubricant because it accumulates the carbon. It can keep piston and the air cylinder walls from biting to match when it work in the condition of losing oil, so it is called accumulating the carbon slot.

The calories that the piston coping absorbs also mainly passes the air cylinder wall through the piston wreath to leak proof department, again spread by the cool water.In a word, the function of the piston head is in addition to install the piston wreath, still seal completely function and transmit heat function, sealing completely the air cylinder together with the piston wreath, keeping combustible admixture spirit from leak crankcase, at the same time pass the(70-80)êlories to the air cylinder wall through the piston wreath.

3. Piston skirt department

The piston skirt department refers to the parts from the bottom of the oil wreathe slot. It includes the pin which is used to pack the piston. The piston skirt department exercises to rise to lead to the function to the piston in the back and forth in the air cylinder, and bear the side pressure. The length of the skirt department is decided by the size and the piston diameter of the side pressure. The so-called side pressure mean in the compression route of travel and make route of travel of efficacy .The level component of the gas pressure which take effect on the piston coping presses the piston to the air cylinder wall. Compress the route of travel and make the side pressure direction of the efficacy route of travel air exactly the opposite, because of the combustion pressure consumedly high in compress the pressure, so, make the side in the route of travel of efficacy pressure also consumedly high in compress the side in the route of travel pressure.Two on the sides that bear the side pressure of the piston skirt department be called to push the dint to face, they be placed in to sell the mutually perpendicular direction of the stalk line with piston up.

Drive Lines

The drive line includes all the parts from the and final drive carry the torque from the engine, the other. The engine torque during acceleration and the torque during braking place loads on the suspension parts.

During suspension repair, it may be essary to disassemble parts of the drive line. Noises produced when the suspension moves may originate from drive line parts. A basic understanding of different drive line assemblies is presented here to give you a working knowledge so that you can do suspension repair.

Drive lines with front-wheel drive often combine the transmission and the final drive into one assembly. This is also true of mid-and rear-engine vehicles. The assembly is called a transaxle, Short half-shafts with universal joints at each end connect between the transaxle and the wheels. These shafts carry power from the final drive to the wheels even when the suspension moves and steers.

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