Wednesday, 5 December 2018

The Cylinder Liner Processing Explained

The cylinder liner forms a cylindrical space in which the piston reciprocates. The main reasons for manufacturing the liner separately from the cylinder block (jacket) in which it is located are as follows:

  • The cylinder liner can be manufactured using a solid material to the cylinder block. While the cylinder block is built from a grey cast iron, the liner is manufactured from a cast iron alloyed with chromium, vanadium, and molybdenum. (Cast iron has graphite which is a lubricant. The alloying elements help improve the wear resistance and resist corrosion at high temperatures.)
  • The cylinder liner wears with the use and therefore it needs to replace.
  • At working temperature, the liner is way hotter than the jacket. The liner will expand more and is free to expand lengthwise and diametrically. If they are selected as a single piece, then unacceptable thermal stress would be set up, causing a fracture in the material.
  • Low risk of defects. The more complex the selection, the more difficult to produce a homogeneous casting with low residual stress.

The Liner tends to get hot during engine operation as the heat energy from the burning fuel is transferred to the cylinder wall. So when the temperature is maintained within acceptable limits, then the liner remains cool.

The Cylinder liners from old low powered engines had a uniform wall thickness and the cooling was achieved by circulating cool water through a space formed between jacket and liner. The cool water space was sealed from the scavenge space using 'O' rings and a tell-tale passage between the 'O' rings led to the outside of the cylinder block to show a leakage.

To increase the power of the engine for a given number of cylinders, either the efficiency of the engine must be more or the fuel must burn more per cycle. To consume more fuel, the volume of the combustion space must be increased, and the mass of air for combustion must be increased. Because of the resulting high pressure in the cylinder from the high combustion of fuel, the liner must be made thicker at the top to accommodate the high hoop stresses, and prevent cracking of the material.

If the thickness of the material is raised to a certain level, then it stands to reason that the working surface of the liner is going to increase in temperature because the cooling water is now further away.

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Engines power machinery, from portable railways to weightlifting cranes, which is why it is necessary to equip the engines with proper devices that can prevent its undue wear and tear. Of all other supplementary equipment, cylinder liners are the simplest and most necessary protectors that have now become an essential part of engines. 

Monday, 16 January 2017

Typical Failures of Internal Combustion Engine Pistons

Manufacturers of automotives have key objective that is to ensure the highest possible reliability and durability of the engine and its parts like piston pins. The piston is an element installed in the crankshaft assembly, which is responsible to convert thermal energy into mechanical. The piston head creates a rotary part of the combustion chamber. The piston grooves are designed in a way to hold piston rings that are used for sealing the cylinder working space.

The major use of piston is to conquest the piston head-space pressure force using the piston head. This force is transferred to the piston, piston pin, through the connecting rod and to the crankshaft. The piston construction has to-

  • Pass on the heat of the hot piston head to the cooled cylinder walls
  • Guide the piston in the cylinder sleeve
  • Take over the pressure on the cylinder bearing surface
  • Make minimum possible friction losses
  • Ensure low lubricating oil consumption by the engine
Manufacturers use distinct range of materials to cast pistons for automotive internal combustion engine-
  1. Cast iron
  2. Alluminium alloys
  3. Alloy steels
Apart from these materials, manufacturers also use aluminium-silicon and aluminium-copper alloys. Aluminium alloys are unique by good formability during casting and machine cutting. However, there is a drawback of these alloys- a large thermal expansion coefficient, low strength, and low hardness.
Automobile Spare Parts Manufacturing Industry’s Essentials And Trends
Cast iron pistons are less manufactured and used. You can see them in low-speed self-ignition engines. They possess good slide properties, retain great mechanical properties at elevated temperatures, and a small thermal expansion.

Due to high strength indices and low thermal expansion, manufacturers have started making pistons with alloy steels.

There are some common reasons behind the failure of the pistons –
  • Lower sparking plug heat factor
  • Too lean air-fuel mixture
  • Valve leakage
  • Insufficient valve clearance
  • Glowing piston head, valve, cylinder head, and sparking plug burning leftover
  • Petrol contamination
  • High engine temperature
Engine overheating occurs due to the malfunctioning of the cooling system, a faulty water pump, fouling, a broken V-belt, and incorrect system. In air cooled engines, overheating occurs because of deposits and fouling inside the cylinder.

Cracks occur due to the excessive loads. Incorrect course of combustion process, incorrect starting of the cold engine, using wrong piston pins.

For more details on defects and failures of engine piston pins, you can browse online articles. You can even ask experts here in comments and wait for their reply.

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Compression rings are among piston pins used as metal sealers that fit between cylinder walls and pistons in internal combustion engines. Each of the rings fits inside the groove around the piston’s outer diameter.

Wednesday, 25 May 2016

How Cylinder Liner Lubrication Perform Inside Marine Diesel Engine?

Manufacturers producing cylinder liners and sleeves are using two distinct types of lubrication for journal bearings and crosshead bearings employed in marine diesel engines. In this post, engineers will share detailed info about lubrication and will also tell about third interesting type of cylinder liner lubrication.

Piston moves to and fro inside a cylinder and engineers have employed many piston rings inside the grooves on the piston that perform several tasks, including pressure sealing inside the combustion chamber. The speed of rubbing (friction) between the cylinder liner and piston rings is high. Other than this, there are extreme temperature conditions, pressure, and corrosive gases within the combustion chamber to which any lubricating oil between the piston and the liner would be used to.

Marine diesel engine is equipped with several components that are in relative motion that can be different kinds- sliding, rotary, or oscillatory. Lubrication is a critical step to make the performance of the device smoother and prevent wearing of the components and damage.

As there are several rotary parts in every engine including marine diesel engines, it is necessary to take care of the device and its components. Though you cannot eliminate the friction completely, but you can lower the friction level by applying apt lubrication techniques. There are four types of motions occurred in a marine engine and thus lubrication should be done accordingly:
  1. There is rotary motion between specific components like crankshafts, camshaft, etc.
  2. Sliding motion between components like cylinders, piston rings, crosshead guide.
  3. Oscillatory motion between components like rocker arms
  4. Line type of friction between components like chain, meshing gear teeth, sprocket wheels, etc.
In general, lubricating oil used inside the cylinder liner should possess viscosity in the range of 115-150 cst at 50 degrees Celsius. You can add special additives to the oil as it may help in enhancing its viscosity. The supply of oil should be ideal as little amount of oil will cause the tear of surfaces and excess of oil will cause damage to various parts, like valve seats, valves, and the exhaust pipes.

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 Running an e-commerce business is not an easy deal as you need to invest a lot more on advertising and marketing of your products. It makes sense when you spend your money on the things that actually work.

Thursday, 4 June 2015

Automobile Parts Businesses In India Growing- What’s The Reason Behind It?

Indian automobile parts market is getting strong each day; annual survey report claims the fact is true. The push in the automotive spare parts business is expected to rise with vehicles demand and sale. As most of the dealers ramp up their inventories of vehicles, they should seek for extra parts to service those automotives. Still some of the small scale businesses look after the ways to enhance their product sales and business growth. In this post, experts will going to share some tricks to grow automotive spare parts business in India.

Sunday, 3 May 2015

How To Buy Spares And Components From Auto Parts Exporters Without Getting Screwed?

Most car owners who seek for servicing centers are often shocked when they find how much it is costly to replace a part. Auto parts exporters are supplying distinct range of spares and auto components; however, fewer parts may cost you more and make holes to your pocket. To avoid coming in contact with such suppliers who offer more expensive automotive parts than others, you need to plan and work according to the strategy.

You can start adopting these steps and discover least expensive or highly affordable exporter to source desired auto parts.

Tuesday, 14 April 2015

How To Replace Valve Seat Inserts In Cylinder Heads?

Valve seat inserts replacement is one of the initial tasks that is often required when rebuilding cast iron or aluminum heads with damaged, cracked, or badly worn seats. If the cylinder head is made from CI material with integral seats, it has to be machined to replace the seat, whereas if the cylinder head is made from aluminum, it has to machine to accept an oversize seat in case of loose, damaged, or deformed bore. In any manner, engineer has to determine the interference amount that is required for the new seat prior cutting the head. Moreover, he needs to decide the seat type for installation.

Thursday, 27 March 2014

Combustion Engines hold its longevity to Piston Pins

All about a piston pin

Regarded as a crucial component for every historic and modern car engine, piston pins provide an unbelievably tough life to combustion engines. It is a link amid the piston as well as the connecting rod. Owing to the fluctuating movement of a piston along with the interface of inertial forces and gas, these are subjected to extreme loads in an alternating direction. 

A piston pin is also known as a wrist pin or gudgeon pin and is basically used for securely fastening a piston with a connecting rod, while permitting ample play to connecting rods for free angular movements in compliance with the needs of the kinematics of an engine assembly. These pins are crucial for a smooth and trouble-free functioning of an engine and thereby ensuring its longer life. Piston pins are generally hollow cylinders developed with special alloy steel possessing hard and highly polished outer surface allowing it to put up with wear and tear owing to the movement of the piston shafts. 

A piston pin is made available in a plethora of types namely diesel engine piston pins, petrol engine piston pin, gas engine piston pin, alloy steel piston pin and automotive piston pin.

Functional Areas 

This mechanical device is a crucial auto part which is perfectly suitable to be utilized in;
·        Petrol, Diesel and Gas Engines
·        Gas and Air Compressors
·        Automobiles
·        LMV and HMV Tractors
·        Heavy Earth Movers
·        Pumps
·        Pneumatic cylinders 

Semi-floating Vs Full floating piston pins 

A piston pin is classified into two forms namely semi-floating and full floating. If the pin is locked to a piston boss or the connecting rod, it is referred as semi-floating. Whereas when the pins are free to spin on the connecting rod bushing and piston bosses, it is referred as full floating. Here the pins are prevented to move outside the pistons and negating the wall of the cylinder with the help of a retaining spring lock. These are particularly manufactured from steel and possess utmost smooth finish for reducing friction. 

Striking attributes of piston pins

To function unfailingly under the stresses and loads, a piston pin offers multiple benefits:
·        High fatigue threshold
·        Strength, rigidity and durability
·        Cost-effective production
·        Superior surface finishes for fine bearing characteristics surrounding the piston assembly
·        Light weight for keeping the inertia force to a minimum
·        Resistance to corrosion
·        Lasting performance
·        Super-finished
·        Easy installation
·        Low maintenance
·        High tensile strength
·        Rust proof 

It is highly imperative to take every engine problem seriously. This makes pistons pins a critical component which renders effective services for optimum performance of the engines.