What Is A Liner In Automobiles? - SKengineers
WHAT IS A CYLINDER LINER?
It is a cylinder that is fitted to the engine block to form
the cylinder, and is one critical function part that forms the engine interior.
In Japan they are usually called Cylinder Liners, but some
countries (companies) call them Cylinder Sleeves.
3
functions of Cylinder Liners -
Function
1 Form the sliding surface -
Reciprocating movement/Liner/Cooling water/Sliding surface
Tightly holds when the valve is seated, prevents compressed
gas or combustion gas leaking into the manifold from between the valve and
Valve Seat.
High burn resistance
Low self-friction
Low friction with the piston ring
Low lubricating oil consumption
Function
2 Heat conduction -
Combustion heat/Liner/Cooling water
Reduces vale and cylinder head friction at the same time.
Function 3
Keep airtightness -
Explosion/Stop the gas/Gas leaks
Prevent compressed gas and combustion gas leaking out. The
liner should not be prone to deformation due to the high pressure/high
temperature inside the cylinder.
The engine's cylinder wall is high temperature/high
pressure, and the piston ring/piston is sliding at high speed, and particularly
with truck/bus engines a long-life is demanded, so we use highly friction
resistant casting material Cylinder Liners only for cylinders. Also, in recent
years, to make engines light-weight, engine blocks are changing from casting to
aluminium alloys, however, aluminium alloys suffer deformation and friction
during direct sliding when used for the cylinder inner circumference, therefore,
the aluminium die cast block is mainly used where the Cylinder Liner is
cast-in.
What is a
Cylinder Liner?
Cylinder
Liner Types and Function :-
A cylinder liner is basically of a cylindrical shape. It is
fitted into the engine block in order to form a cylinder. In the composition of
the interior of an engine, the cylinder liner is a very important part. The
word cylinder liner is popular in Japan, however in other countries it is also
known as Cylinder sleeve. When the motor is operated, there is a considerable
amount of wear and tear of the piston. The cylinder liners thereby being the
interior metal component saves considerable amount of wear and tear of the
piston. When an engine works, the piston as well as the piston rings slide with
great speeds. Due to this there is high pressure and high temperature generated
in the cylindrical wall of the engine.
Hence, to maintain the longer service life of buses, trucks etc cast iron
cylinders are used.
The reason behind using the cast iron cylinders is that they
have brilliant wear- resisting properties and hence they prove to be very
efficient when used for cylinder parts. However, in the recent times Aluminium
alloys are gaining widespread popularity due to its light weight. Lighter
engines are now preferred over the heavy engines. But the aluminium alloy
cylinder suffers with the demerit of deformation during operation when the
direct sliding motion of the piston and the piston rings take place. Also it
has poor wear-resistance. For this reason, the cast iron cylinders are still
not out of fashion and are used especially for heavy automobiles.
Function
of Cylinder Liners -
A cylinder liner is the central working part of a
reciprocating engine or pump, the space in which a piston travels. Problem of
the cylinder wear is considerable and this has been solved by the use of
cylinder liners. The cylinder liners are in the form of barrels made of special
alloy iron containing silicon, manganese, nickel and chromium. They are
centrifugally casted. Now a day’s
cylinder liners are fitted on the engines of cars and commercial vehicles.
These liners are of oil hardening type and offer considerably longer life for
the engine.
1.
Formation of Sliding Surface -
The major function of a cylinder liner is forming a sliding
surface for the piston rings. It serves as the inner wall of a cylinder. It
also retains the lubricant within itself. Also it’s another most important
function is the excellent characteristic as sliding surface and these four
necessary points.
•It has high anti-galling properties
• There is less wear on the cylinder liner itself
• There is less wear on the partner piston ring
• There is less consumption of lubricant
2. Heat Transfer -
The cylinder liner transmits the heat to the coolant .It
receives the heat from the combustion through the piston and piston rings.
3.
Compression Gas Sealing -
The compressed gas as well as the combustion gas is
prevented from escaping by the compression gas sealing.
Types of
Cylinder Liners -
Cylinder Liner Types and Function: There are basically three
different types of cylinder liners namely, Dry, wet and finned. Each and every
type of cylinder liner uses slightly different method to work. However, the
basic principle remains the same that is to protect the piston from heat and
impurities. The cylinder liners are specially designed products. They are
expensive and requires precise manufacturing. Hence they are only available at
special motor parts.
1. Dry
Liners -
The dry liner is made in the shape of barrel having a flange
at the top which keeps it into position in the cylinder block. The entire outer
surface of the dry liners bears against the cylinder block casting and hence
has to be machined very accurately from outside also. Thus, it is not in direct
contact with the cooling water and hence is known as dry liners. Its thickness
ranges from 1.5 mm to 3 mm. It is used mostly for reconditioning worn
cylinders.
2. Wet
Liners (Water Cooled Liners) -
A wet liner makes up
a complete cylinder barrel. It is provided with the flange at the top
which fits into the groove in the cylinder block. At the bottom of the block or
the liner is provided with grooves, generally three in numbers, in which the
packing rings made of rubber are inserted. The liner is in direct contact with
the cooling water hence it is known as wet liner. The outer surface of the wet
liner does not require accurate machining. Headliners article than dry liners
as they range from 1.5 mm to 6 mm.
Advantages
of wet liners over dry liners -
A wet liner can be replaced easily and for this purpose
there is no need of any special tool or equipment.
A wet liner reduces the temperature of the piston by being
in direct contact with circulating water.
A wet liner has to be provided a leak proof joint between
the cylinder casting and the liner whereas there is no such requirement of dry
liner.
A wet liner is free to expand without any resistance since
it is held by a flange only at the top.
A wet liner required simple construction of cylinder block
without any accurate machining on the inside surface of cylinder block.
A wet liner can be finished accurately before fitting,
whereas a dry liner cannot be finished accurately before fitting because of the
shrinkage stresses produced.
3. Finned
Cylinder Liners (Air-Cooled Liners) -
Heat and impurity resistant metal is used for the
construction of finned cylinder liners. Primarily designed for the air-cooled
engines, the finned cylinder liners works pretty much the same as dry cylinder
liners. Fitted with tiny fins in order to allow the air which is flowing in to
draw with a great force to achieve cooling of the cylinder.
Car boot
liner -
A tailored car boot liner for the Range Rover Evoque, Designed
and manufactured by The Hatchbag Company
A car boot liner or cargo liner is a synthetic mat designed
to protect the automobile boot or trunk against damage from dirt or spills and
to pad cargo against abrasion or shock. Specifically, a boot liner shields the
vehicle carpet from damage. Boot liners are usually removable so they may be
cleaned or replaced.
Contents
1 Types
2 Materials
3 Patent
4 See also
5 References
Types -
The standard PVC boot liner is universal in nature and then
trimmed to fit by the end user. It is ideally developed for simple shaping and
is flat in nature and subsequently offers less protective qualities.
Alternatively there are boot liners made from rubber that
are tailor / "custom made" to fit the flat space of a vehicle's
specific cargo area. Typically, these mats have a channelled, repeated upper
design and raised edges. The top surface design is usually non-slip in nature
and helps to prevent spills and liquid leakages occurring in the internal cargo
space.
Both universal and "custom" boot liners can be
rolled up and removed or replaced if necessary.
TPE or a form of thermoplastic is a common material used in
boot liners.
There are also highly tailored boot liners available often
made from PVC or Cloth, These liners offer protection for the boot area (floor,
sides and back of seats) and are often available in several configurations and
colours as specified by the customer. These liners are usually specifically
designed for individual car models.
Those wanting to protect all of the interior of the boot
(floor, sides and back of seats including the roof lining and bumper bar) can
use a heavy duty polyester boot liner. These are designed to be fitted when
needed [3] and stored under the seat or in the spare tyre area when not. This
type of liner can withstand heavy domestic use and are water resistant (not
waterproof). They are not tailored to a specific vehicle and are available in
small and large sizes to suit most hatches, wagons, SUVs and 4WD vehicles.
Some boot liners are designed to overlap over the bumper edge
to prevent damage during loading. This has been developed also by car
manufacturers to offer all-around protection.
Materials
-
Boot liners are commonly made with several different types
of synthetic or natural rubber.
Natural rubber.
Styrene-butadiene.
Thermoplastic elastomer.
Low-density polyethylene.
Polyester.
Comments
Post a Comment