How is crosshead lubricated?

The crosshead on a slow speed 2 stroke is a difficult bearing to lubricate effectively. Instead the lubrication starts as boundary, and as the rubbing speed increases, a hydrodynamic film is built up. As the rubbing speed decreases the lubrication becomes boundary once again.

Which lubrication is used in 2 stroke engine?

In two-stroke engines, mist lubrication is used where crankcase lubrication is not suitable. In a two-stroke engine, as the charge is compressed in the crankcase, it is not possible to have the lubricating oil in the sump. Hence, mist lubrication is adopted in practice.

How do you lubricate a 2 stroke engine?

Two-stroke lubrication Two-stroke engines collect some oil beneath the crankshaft; however, 2-stroke engines use a total-loss lubrication system that combines oil and fuel to provide both energy and engine lubrication.

What type of lubrication is used in 2 stroke marine diesel?

Types of Lubrication Systems

• Hydrodynamic Lubrication: In this type of lubrication, the oil forms a continuous oil film of adequate thickness between the moving surfaces.
• Hydrostatic Lubrication: Where oil film cannot be formed due to the motion of moving parts, the oil pressure has to be supplied externally.

Why crosshead lubrication is difficult?

The crosshead on a slow speed 2 stroke is a difficult bearing to lubricate effectively. The load is continually downward and because the con rod swings about the pin, changing direction each stroke, true hydrodynamic lubrication cannot take place.

What is hydrostatic lubrication?

Hydrostatic lubrication is essentially a form of hydrodynamic lubrication in which the metal surfaces are separated by a complete film of oil, but instead of being self-generated, the separating pressure is supplied by an external oil pump. The oil is supplied under pressure at the bottom of bearing.

Do 2 stroke motors need oil?

Unlike a four-stroke engine, a unique feature of a two-stroke engine is that they do not have an internal oil reservoir. Instead, two-stroke engines require the owner to mix oil into the fuel at a predetermined ratio in order to ensure the engine receives adequate lubrication during operation.

What is one of the main features of the cylinder lubricating oil used in large 2 stroke marine diesel engines which normally operate on heavy fuel oil?

The cylinder lubricant has two functions; firstly to provide an oil film in the cylinder liner to reduce abrasive wear, and secondly to neutralise acidic combustion by-products generated from the sulphur contained in the fuel through the BN or alkaline base number in the lubricant.

How is the crankshaft lubricated on a 2 stroke engine?

Lubrication. Two-stroke engines use their crankcase to pressurize the air-fuel mixture before transfer to the cylinder. Unlike four-stroke engines, they cannot be lubricated by oil contained in the crankcase and sump: lubricating oil would be swept up and burnt with the fuel.

Does 2 stroke engine need oil?

What is lubrication in marine diesel engine?

The lubrication system of an engine provides a supply of lubricating oil to the various moving parts in the engine. Its main function is to enable the formation of a film of oil between the moving parts, which reduces friction and wear.

What are marine lubricants?

Marine lubrication includes the use of ancillary grades such as hydraulic oils, compressor oils, gear oils, grease, etc. In addition, the ship operator fre- quently requires advice on lubrication and related problems, together with a used oil analysis service.

Can you use 4 stroke lubrication on crosshead engine?

A slightly more ambitious idea is to apply the four-stroke trunk piston engine cylinder lubrication concept to the two-stroke crosshead engine, i.e. to “over-lubricate” the cylinder liner, apply an oil scraper ring, and then collect the surplus oil, clean it, and recycle it.

How is the crosshead of a marine engine lubricated?

Crosshead Lubrication. The type of motion of the crosshead of a marine diesel engine is oscillatory in nature wherein it oscillates to a few degrees on either side of the center of oscillation. Apart from that the speed of oscillation is not very significant which in turn means that it will not generate a pumping action for lubrication unlike…

Can a two stroke engine be used as a four stroke engine?

In a four-stroke engine and in a small number of niche two-strokes models, the construction of the engine allows the lubricant used in the crankcase to also lubricate the cylinder liner and piston interface. However, the vast majority of two-stroke engines used in the marine sphere are of the crosshead -stroke type.

What does cylinder lubrication do on a diesel engine?

Cylinder lubrication is an accessory applied to facilitate the operation of a two- stroke crosshead diesel engine. Failure in operation may cause considerable damage and can render an engine inoperative.