The automotive liner in automobile engines essentially forms a surface against which the piston inside the cylinder moves. It is one of the most important functioning surfaces of a cylinder. This surface has to be strong enough to withstand wear and tear from the movement of the piston against it. Sometimes, the liner is made separate from the cylinder and other times it comes as an integral part of the cylinder at purchase.
The Purpose of Automotive Liners
Commonly, in an engine that works on gasoline, the liners are not replaceable. Which means that when they are worn out, the entire cylinder will need to be replaced. Eventually, the entire engine block will need replacement. This is avoidable in diesel engines where the automotive liners are manufactured separate from the cylinders and are removed to fit a new one.
- The automotive liner provides a sliding surface for the piston and also has to withstand the heat of the combustion at the top portion of the cylinder, wherein the combustion takes place.
- The automotive cylinder lining, along with the piston, must transfer the heat away from the cylinder without raising the temperature of the cylinder too much. In wet automotive liners, the cylinders are able to withstand a much higher level of heat and performance demand, since the liner surface is constantly in touch with the coolant.
- The cylinder and its lining together make sure that the gas inside it remains compressed and does not escape, maintaining a constant pressure and temperature.
Automotive Liners in Diesel Engines
Diesel engines generally have replaceable automotive liners and are made from a few different varieties of metals and alloys depending upon the purpose they are expected to serve.
- For lighter diesel automobile engines, a thin-walled dry liner is preferred as the small cylinder bore distance makes it easier to achieve this purpose.
- A nitriding automotive liner is used in diesel engines of automobiles because it has anti-galling properties that make it a smooth surface against which the piston can slide up and down while working.
- A phosphate coated automotive liner with its specifications for wet and dry liners also has anti-galling properties that make it useful in diesel automobile engines.
- To prevent cavitation in diesel engines, a chromium-plated wet liner is useful.
Wet and Dry Liners
Wet and dry liners are the two types of automotive liners that are manufactured for use in automobiles. The wet liners are typically known to have a greater advantage over dry liners for a few reasons:
- A wet liner is easier to replace as compared to a dry liner and does not really need any special tools for this purpose.
- Since it is in constant contact with the coolant, it’s more efficient at keeping the piston and the cylinder from overheating.
- Since a wet liner is held only by a flange at the top, it has more room to expand when the cylinder is working and heats up.
- A wet liner can be given finishing touches before it is installed, whereas a dry liner cannot be treated this way before its fit since there is the possibility of it being damaged by shrinkage stress.
The recent demands for efficiency and fuel saving by customers have pushed many auto liner exporters and manufacturers to produce better quality automotive liners that can prevent any damage from occurring to the cylinder walls inside the engine. This is a good reason to use them in automobile engines to ensure that the cost of maintenance and repair comes down when engine blocks do not need to be replaced.